Science.gov

Sample records for fiber laser based

  1. Mode-locked fiber lasers based on doped fiber arrays.

    PubMed

    Zhang, Xiao; Song, Yanrong

    2014-05-10

    We designed a new kind of mode-locked fiber laser based on fiber arrays, where the central core is doped. A theoretical model is given for an all-fiber self-starting mode-locked laser based on this kind of doped fiber array. Two different kinds of fiber lasers with negative dispersion and positive dispersion are simulated and discussed. The stable mode-locked pulses are generated from initial noise conditions by the realistic parameters. The process of self-starting mode-locking multipulse transition and the relationship between the energy of the central core and the propagation distance of the pulses are discussed. Finally, we analyze the difference between the averaged mode-locked laser and the discrete mode-locked laser.

  2. Tapered fiber based high power random laser.

    PubMed

    Zhang, Hanwei; Du, Xueyuan; Zhou, Pu; Wang, Xiaolin; Xu, Xiaojun

    2016-04-18

    We propose a novel high power random fiber laser (RFL) based on tapered fiber. It can overcome the power scaling limitation of RFL while maintaining good beam quality to a certain extent. An output power of 26.5 W has been achieved in a half-open cavity with one kilometer long tapered fiber whose core diameter gradually changes from 8 μm to 20 μm. The steady-state light propagation equations have been modified by taking into account the effective core area to demonstrate the tapered RFL through numerical calculations. The numerical model effectively describes the power characteristics of the tapered fiber based RFL, and both the calculating and experimental results show higher power exporting potential compared with the conventional single mode RFL. PMID:27137338

  3. Multi-wavelength narrow linewidth fiber laser based on distributed feedback fiber lasers

    NASA Astrophysics Data System (ADS)

    Lv, Jingsheng; Qi, Haifeng; Song, Zhiqiang; Guo, Jian; Ni, Jiasheng; Wang, Chang; Peng, Gangding

    2016-09-01

    A narrow linewidth laser configuration based on distributed feedback fiber lasers (DFB-FL) with eight wavelengths in the international telecommunication union (ITU) grid is presented and realized. In this laser configuration, eight phase-shifted gratings in series are bidirectionally pumped by two 980-nm laser diodes (LDs). The final laser output with over 10-mW power for each wavelength can be obtained, and the maximum power difference within eight wavelengths is 1.2 dB. The laser configuration with multiple wavelengths and uniform power outputs can be very useful in large scaled optical fiber hydrophone fields.

  4. Femtosecond Fiber Lasers Based on Dissipative Processes for Nonlinear Microscopy

    PubMed Central

    Wise, Frank W.

    2012-01-01

    Recent progress in the development of femtosecond-pulse fiber lasers with parameters appropriate for nonlinear microscopy is reviewed. Pulse-shaping in lasers with only normal-dispersion components is briefly described, and the performance of the resulting lasers is summarized. Fiber lasers based on the formation of dissipative solitons now offer performance competitive with that of solid-state lasers, but with the benefits of the fiber medium. Lasers based on self-similar pulse evolution in the gain section of a laser also offer a combination of short pulse duration and high pulse energy that will be attractive for applications in nonlinear bioimaging. PMID:23869163

  5. Femtosecond Fiber Lasers Based on Dissipative Processes for Nonlinear Microscopy.

    PubMed

    Wise, Frank W

    2012-01-01

    Recent progress in the development of femtosecond-pulse fiber lasers with parameters appropriate for nonlinear microscopy is reviewed. Pulse-shaping in lasers with only normal-dispersion components is briefly described, and the performance of the resulting lasers is summarized. Fiber lasers based on the formation of dissipative solitons now offer performance competitive with that of solid-state lasers, but with the benefits of the fiber medium. Lasers based on self-similar pulse evolution in the gain section of a laser also offer a combination of short pulse duration and high pulse energy that will be attractive for applications in nonlinear bioimaging.

  6. Development of Fiber-Based Laser Systems for LISA

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Camp, Jordan

    2010-01-01

    We present efforts on fiber-based laser systems for the LISA mission at the NASA Goddard Space Flight Center. A fiber-based system has the advantage of higher robustness against external disturbances and easier implementation of redundancies. For a master oscillator, we are developing a ring fiber laser and evaluating two commercial products, a DBR linear fiber laser and a planar-waveguide external cavity diode laser. They all have comparable performance to a traditional NPRO at LISA band. We are also performing reliability tests of a 2-W Yb fiber amplifier and radiation tests of fiber laser/amplifier components. We describe our progress to date and discuss the path to a working LISA laser system design.

  7. All-Fiber Configuration Laser Self-Mixing Doppler Velocimeter Based on Distributed Feedback Fiber Laser.

    PubMed

    Wu, Shuang; Wang, Dehui; Xiang, Rong; Zhou, Junfeng; Ma, Yangcheng; Gui, Huaqiao; Liu, Jianguo; Wang, Huanqin; Lu, Liang; Yu, Benli

    2016-01-01

    In this paper, a novel velocimeter based on laser self-mixing Doppler technology has been developed for speed measurement. The laser employed in our experiment is a distributed feedback (DFB) fiber laser, which is an all-fiber structure using only one Fiber Bragg Grating to realize optical feedback and wavelength selection. Self-mixing interference for optical velocity sensing is experimentally investigated in this novel system, and the experimental results show that the Doppler frequency is linearly proportional to the velocity of a moving target, which agrees with the theoretical analysis commendably. In our experimental system, the velocity measurement can be achieved in the range of 3.58 mm/s-2216 mm/s with a relative error under one percent, demonstrating that our novel all-fiber configuration velocimeter can implement wide-range velocity measurements with high accuracy. PMID:27472342

  8. All-Fiber Configuration Laser Self-Mixing Doppler Velocimeter Based on Distributed Feedback Fiber Laser

    PubMed Central

    Wu, Shuang; Wang, Dehui; Xiang, Rong; Zhou, Junfeng; Ma, Yangcheng; Gui, Huaqiao; Liu, Jianguo; Wang, Huanqin; Lu, Liang; Yu, Benli

    2016-01-01

    In this paper, a novel velocimeter based on laser self-mixing Doppler technology has been developed for speed measurement. The laser employed in our experiment is a distributed feedback (DFB) fiber laser, which is an all-fiber structure using only one Fiber Bragg Grating to realize optical feedback and wavelength selection. Self-mixing interference for optical velocity sensing is experimentally investigated in this novel system, and the experimental results show that the Doppler frequency is linearly proportional to the velocity of a moving target, which agrees with the theoretical analysis commendably. In our experimental system, the velocity measurement can be achieved in the range of 3.58 mm/s–2216 mm/s with a relative error under one percent, demonstrating that our novel all-fiber configuration velocimeter can implement wide-range velocity measurements with high accuracy. PMID:27472342

  9. All-Fiber Configuration Laser Self-Mixing Doppler Velocimeter Based on Distributed Feedback Fiber Laser.

    PubMed

    Wu, Shuang; Wang, Dehui; Xiang, Rong; Zhou, Junfeng; Ma, Yangcheng; Gui, Huaqiao; Liu, Jianguo; Wang, Huanqin; Lu, Liang; Yu, Benli

    2016-07-27

    In this paper, a novel velocimeter based on laser self-mixing Doppler technology has been developed for speed measurement. The laser employed in our experiment is a distributed feedback (DFB) fiber laser, which is an all-fiber structure using only one Fiber Bragg Grating to realize optical feedback and wavelength selection. Self-mixing interference for optical velocity sensing is experimentally investigated in this novel system, and the experimental results show that the Doppler frequency is linearly proportional to the velocity of a moving target, which agrees with the theoretical analysis commendably. In our experimental system, the velocity measurement can be achieved in the range of 3.58 mm/s-2216 mm/s with a relative error under one percent, demonstrating that our novel all-fiber configuration velocimeter can implement wide-range velocity measurements with high accuracy.

  10. Multi-wavelength fiber laser based on a fiber Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Estudillo-Ayala, J. M.; Jauregui-Vazquez, D.; Haus, J. W.; Perez-Maciel, M.; Sierra-Hernandez, J. M.; Avila-Garcia, M. S.; Rojas-Laguna, R.; Lopez-Dieguez, Y.; Hernandez-Garcia, J. C.

    2015-12-01

    In this work we report experimental studies of an erbium-doped fiber laser design that simultaneously emits up to three wavelengths. The laser cavity configuration has an all-fiber, Fabry-Perot interferometer, based on the insertion of air cavities in the fiber, near one end of a conventional single-mode fiber. The laser emissions have a side-mode suppression ratio over 25 dB, wavelength variations around 0.04 nm, and 2 dB power fluctuations. By using a simple, controlled fiber curvature technique cavity losses are varied over a section of convectional single-mode fiber and the laser output is switched between single-, dual-, and triple-wavelength emission. Moreover, by applying a refractive index change over the fiber filter the emission wavelengths are shifted. The fiber laser offers a compact, simple, and low-cost design for a multiple wavelength outputs that can be adopted in future applications.

  11. Process observation in fiber laser-based selective laser melting

    NASA Astrophysics Data System (ADS)

    Thombansen, Ulrich; Gatej, Alexander; Pereira, Milton

    2015-01-01

    The process observation in selective laser melting (SLM) focuses on observing the interaction point where the powder is processed. To provide process relevant information, signals have to be acquired that are resolved in both time and space. Especially in high-power SLM, where more than 1 kW of laser power is used, processing speeds of several meters per second are required for a high-quality processing results. Therefore, an implementation of a suitable process observation system has to acquire a large amount of spatially resolved data at low sampling speeds or it has to restrict the acquisition to a predefined area at a high sampling speed. In any case, it is vitally important to synchronously record the laser beam position and the acquired signal. This is a prerequisite that allows the recorded data become information. Today, most SLM systems employ f-theta lenses to focus the processing laser beam onto the powder bed. This report describes the drawbacks that result for process observation and suggests a variable retro-focus system which solves these issues. The beam quality of fiber lasers delivers the processing laser beam to the powder bed at relevant focus diameters, which is a key prerequisite for this solution to be viable. The optical train we present here couples the processing laser beam and the process observation coaxially, ensuring consistent alignment of interaction zone and observed area. With respect to signal processing, we have developed a solution that synchronously acquires signals from a pyrometer and the position of the laser beam by sampling the data with a field programmable gate array. The relevance of the acquired signals has been validated by the scanning of a sample filament. Experiments with grooved samples show a correlation between different powder thicknesses and the acquired signals at relevant processing parameters. This basic work takes a first step toward self-optimization of the manufacturing process in SLM. It enables the

  12. Fiber-optic Doppler velocimeter based on a dual-polarization fiber grating laser

    NASA Astrophysics Data System (ADS)

    Kuang, Zeyuang; Cheng, Linghao; Liang, Yizhi; Liang, Hao; Guan, Bai-Ou

    2015-07-01

    A fiber-optic Doppler velocimeter based on a dual-polarization fiber grating laser is demonstrated. The fiber grating laser produces two orthogonally polarized laser outputs with their frequency difference proportional to the intra-cavity birefringence. When the laser outputs are reflected from a moving targets, the laser frequencies will be shifted due to the Doppler effect. It shows that the frequency difference between the beat note of the laser outputs and the beat note of the reflected lasers is proportional to the velocity. The proposed fiber-optic Doppler velocimeter shows a high sensitivity of 0.64 MHz/m/s and is capable of measurement of wide range of velocity.

  13. Fiber Sensor Systems Based on Fiber Laser and Microwave Photonic Technologies

    PubMed Central

    Fu, Hongyan; Chen, Daru; Cai, Zhiping

    2012-01-01

    Fiber-optic sensors, especially fiber Bragg grating (FBG) sensors are very attractive due to their numerous advantages over traditional sensors, such as light weight, high sensitivity, cost-effectiveness, immunity to electromagnetic interference, ease of multiplexing and so on. Therefore, fiber-optic sensors have been intensively studied during the last several decades. Nowadays, with the development of novel fiber technology, more and more newly invented fiber technologies bring better and superior performance to fiber-optic sensing networks. In this paper, the applications of some advanced photonic technologies including fiber lasers and microwave photonic technologies for fiber sensing applications are reviewed. FBG interrogations based on several kinds of fiber lasers, especially the novel Fourier domain mode locking fiber laser, have been introduced; for the application of microwave photonic technology, examples of microwave photonic filtering utilized as a FBG sensing interrogator and microwave signal generation acting as a transversal loading sensor have been given. Both theoretical analysis and experimental demonstrations have been carried out. The comparison of these advanced photonic technologies for the applications of fiber sensing is carried out and important issues related to the applications have been addressed and the suitable and potential application examples have also been discussed in this paper. PMID:22778591

  14. Fiber-laser-based photoacoustic microscopy and melanoma cell detection

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Maslov, Konstantin; Zhang, Yu; Hu, Song; Yang, Lihmei; Xia, Younan; Liu, Jian; Wang, Lihong V.

    2011-01-01

    For broad applications in biomedical research involving functional dynamics and clinical studies, a photoacoustic microscopy system should be compact, stable, and fast. In this work, we use a fiber laser as the photoacoustic irradiation source to meet these goals. The laser system measures 45×56×13 cm3. The stability of the laser is attributed to the intrinsic optical fiber-based light amplification and output coupling. Its 50-kHz pulse repetition rate enables fast scanning or extensive signal averaging. At the laser wavelength of 1064 nm, the photoacoustic microscope still has enough sensitivity to image small blood vessels while providing high optical absorption contrast between melanin and hemoglobin. Label-free melanoma cells in flowing bovine blood are imaged in vitro, yielding measurements of both cell size and flow speed.

  15. Novel fiber-MOPA-based high power blue laser

    NASA Astrophysics Data System (ADS)

    Engin, Doruk; Fouron, Jean-Luc; Chen, Youming; Huffman, Andromeda; Fitzpatrick, Fran; Burnham, Ralph; Gupta, Shantanu

    2012-06-01

    5W peak power at 911 nm is demonstrated with a pulsed Neodymium (Nd) doped fiber master oscillator power amplifier (MOPA). This result is the first reported high gain (16dB) fiber amplifier operation at 911nm. Pulse repetition frequency (PRF) and duty-cycle dependence of the all fiber system is characterized. Negligible performance degreadation is observed down to 1% duty cycle and 10 kHz PRF, where 2.5μJ of pulse energy is achieved. Continuous wave (CW) MOPA experiments achieved 55mW average power and 9dB gain with 15% optical to optical (o-o) efficiency. Excellent agreement is established between dynammic fiber MOPA simulation tool and experimental results in predicting output amplified spontaneous emission (ase) and signal pulse shapes. Using the simulation tool robust Stimulated Brillion Scattering (SBS) free operation is predicted out of a two stage all fiber system that generates over 10W's of peak power with 500 MHz line-width. An all fiber 911 nm pulsed laser source with >10W of peak power is expected to increase reliability and reduce complexity of high energy 455 nm laser system based on optical parametric amplification for udnerwater applications. The views expressed are thos of the author and do not reflect the official policy or position of the Department of Defense or the U.S. Government.

  16. All-fiber amplifier similariton laser based on a fiber Bragg grating filter.

    PubMed

    Olivier, Michel; Gagnon, Mathieu; Duval, Simon; Bernier, Martin; Piché, Michel

    2015-12-01

    This article presents, for the first time to our knowledge, an all-fiber amplifier similariton laser based on a fiber Bragg grating filter. The laser emits 2.9 nJ pulses at a wavelength of 1554 nm with a repetition rate of 31 MHz. The dechirped pulses have a duration of 89 fs. The characteristic features of the pulse profile and spectrum along with the dynamics of the laser are highlighted in representative simulations. These simulations also address the effect of the filter shape and detuning with respect to the gain spectral peak. PMID:26625073

  17. All-optical fiber anemometer based on laser heated fiber Bragg gratings.

    PubMed

    Gao, Shaorui; Zhang, A Ping; Tam, Hwa-Yaw; Cho, L H; Lu, Chao

    2011-05-23

    A fiber-optic anemometer based on fiber Bragg gratings (FBGs) is presented. A short section of cobalt-doped fiber was utilized to make a fiber-based "hot wire" for wind speed measurement. Fiber Bragg gratings (FBGs) were fabricated in the cobalt-doped fiber using 193 nm laser pulses to serve as localized temperature sensors. A miniature all-optical fiber anemometer is constructed by using two FBGs to determine the dynamic thermal equilibrium between the laser heating and air flow cooling through monitoring the FBGs' central wavelengths. It was demonstrated that the sensitivity of the sensor can be adjusted through the power of pump laser or the coating on the FBG. Experimental results reveal that the proposed FBG-based anemometer exhibits very good performance for wind speed measurement. The resolution of the FBG-based anemometer is about 0.012 m/s for wind speed range between 2.0 m/s and 8.0 m/s.

  18. Switchable multi-wavelength fiber laser based on modal interference

    NASA Astrophysics Data System (ADS)

    Ma, Lin; Jiang, Sun; Qi, Yan-Hui; Kang, Ze-Xin; Jian, Shui-Sheng

    2015-08-01

    A comb fiber filter based on modal interference is proposed and demonstrated in this paper. Here two cascaded up-tapers are used to excite the cladding mode, and a core-offset jointing point is used to act as an interference component. Experimental results show that this kind of structure possesses a comb filter property in a range of the C-band. The measured extinction ratio is better than 12 dB with an insertion loss of about 11 dB. A switchable multi-wavelength erbium-doped fiber laser based on this novel comb filter is demonstrated. By adjusting the polarization controller, the output laser can be switched among single-, dual-, and three-wavelengths with a side mode suppression ratio of better than 45 dB.

  19. A wavelength-tunable fiber laser based on a twin-core fiber comb filter

    NASA Astrophysics Data System (ADS)

    Zou, Hui; Lou, Shuqin; Yin, Guolu

    2013-02-01

    A wavelength-tunable fiber laser based on a twin-core fiber (TCF) comb filter is proposed and demonstrated. The TCF comb filter is fabricated by splicing a 0.85 m long TCF between two standard single mode fibers (SMFs) and with exhibits a good linear strain characteristic with a sensitivity of 1.23 pm/μɛ. The wavelength of the laser can be linearly tuned from 1558.04 nm to 1553.62 nm by applying an axial strain to the TCF comb filter. The optical signal-to-noise ratio (OSNR) of the fiber laser reaches 45 dB. The 3 dB bandwidth is 0.02 nm. The fluctuation of the laser peak in the output power and the wavelength is less than 0.5 dB and within 0.05 nm, respectively. The fiber laser has the advantages of having a simple structure and stable operation under room temperature.

  20. All-fiberized SBS-based high repetition rate sub-nanosecond Yb fiber laser for supercontinuum generation

    NASA Astrophysics Data System (ADS)

    Hua, Dacheng; Su, Jianjia; Cui, Wei; Yan, Yaxi; Jiang, Peipei

    2014-12-01

    We report an all-fiberized SBS-based high repetition rate sub-nanosecond Yb fiber laser for supercontinuum generation. The high repetition rate ns laser pulses were produced from a fiber Bragg grating (FBG)-constructed fiber laser cavity consisting of a piece of double cladding Yb fiber as the gain medium and a short piece of Bi/Cr-doped fiber as a saturable absorber (SA). By optimizing the fiber length of the Bi/Cr-doped fiber and the reflectivity of the FBG, the Q-switching state of the fiber laser can be adjusted so that the energy storing condition within the fiber cavity can assure the start of stimulated Brillouin scattering (SBS) and as a result, compress the laser pulse duration. The fiber laser had an average laser power output of 1.2 W at 1064 nm with pulse repetition rate of about 80 kHz, almost four times the reported results. The pulse duration was about 1 ns with peak power of about 15 kW. After one stage of amplification, the laser power was raised to about 3 W and was used to pump a 20 m long photonic crystal fiber (PCF). Supercontiuum (SC) laser output was obtained with average power up to 1.24 W and spectrum spanning from 550 to 2200 nm.

  1. Detection of rail corrugation based on fiber laser accelerometers

    NASA Astrophysics Data System (ADS)

    Huang, Wenzhu; Zhang, Wentao; Du, Yanliang; Sun, Baochen; Ma, Huaixiang; Li, Fang

    2013-09-01

    Efficient inspection methods are necessary for detection of rail corrugation to improve the safety and ride quality of railway operations. This paper presents a novel fiber optic technology for detection of rail corrugation based on fiber laser accelerometers (FLAs), tailored to the measurement of surface damage on rail structures. The principle of detection of rail corrugation using double integration of axle-box acceleration is presented. Then we present the theoretical model and test results of FLAs which are installed on the bogie to detect the vertical axle-box acceleration of the train. Characteristics of high sensitivity and large dynamic range are achieved when using fiber optic interferometric demodulation. A flexible inertial algorithm based on double integration and the wavelet denoising method is proposed to accurately estimate the rail corrugation. A field test is carried out on the Datong-Qinhuangdao Railway in north China. The test results are compared with the results of a rail inspection car, which shows that the fiber laser sensing system has a good performance in monitoring rail corrugation.

  2. Wavelength-tunable, passively mode-locked fiber laser based on graphene and chirped fiber Bragg grating.

    PubMed

    He, Xiaoying; Liu, Zhi-bo; Wang, D N

    2012-06-15

    We demonstrate a wavelength-tunable, passively mode-locked erbium-doped fiber laser based on graphene and chirped fiber Bragg grating. The saturable absorber used to enable passive mode-locking in the fiber laser is a section of microfiber covered by graphene film, which allows light-graphene interaction via the evanescent field of the microfiber. The wavelength of the laser can be continuously tuned by adjusting the chirped fiber Bragg grating, while maintaining mode-locking stability. Such a system has high potential in tuning the mode-locked laser pulses across a wide wavelength range.

  3. A dual-wavelength erbium-doped fiber laser based on fiber grating pair

    NASA Astrophysics Data System (ADS)

    Sun, Hongwei; Wang, Tianshu; Jia, Qingsong; Zhang, Peng; Jiang, Huilin

    2014-12-01

    A dual-wavelength linear cavity erbium-doped fiber (EDF) laser based on a fiber grating pair is demonstrated experimentally. A circulator, a 980nm/1550nm wavelength division multiplexing (WDM) coupler, a 1×2 coupler, a polarization controller, a 6m long erbium-doped fiber and a fiber grating pair for wavelength interval of 0.3nm are included in the structure. A circulator connected at two ports as reflecting mirror structure. A 980nm pump source pump an erbium-doped fiber with a length of 6m consist of an erbium doped fiber amplifier. Through adjusting the state of the polarization controller, the transmission characteristic of cavity is changed. In both polarization and wavelength, the feedback from the fiber grating pair results in the laser operating on two longitudinal modes that are separated. The birefringence induced by the fiber grating pair is beneficial to diversify the polarization states of different wavelength in the erbium-doped fiber. So it is enhanced the polarization hole burning effect. This polarization hole burning effect greatly reduced the wavelength competition. Then, it was possible to achieve stable dual-wavelength. It turns out the structure generated the stable dual-wavelength with the 0.3nm wavelength interval and the output power is 0.13dBm in the end. The whole system have a simple and compact structure, it can work stably and laid a foundation for microwave/millimeter wave generator. It has a good application performance in the future for scientific research and daily life.

  4. Dual-wavelength erbium-doped fiber laser with tunable wavelength spacing using a twin core fiber-based filter

    NASA Astrophysics Data System (ADS)

    Yin, Guolu; Lou, Shuqin; Wang, Xin; Han, Bolin

    2014-05-01

    A dual-wavelength erbium-doped fiber laser with tunable wavelength spacing was proposed and experimentally demonstrated by using a twin core fiber (TCF)-based filter. Benefiting from the polarization dependence of the TCF-based filter, the laser operated in dual-wavelength oscillation with two orthogonal polarization states. By adjusting the polarization controller, the wavelength spacing was tuned from 0.1 nm to 1.2 nm without shifting the centre position of the two wavelengths. By stretching the TCF, the two wavelengths were simultaneously tuned with fixed wavelength spacing. Such a dual-wavelength fiber laser could find applications in optical fiber sensors and microwave photonics generation.

  5. PCF based high power narrow line width pulsed fiber laser

    NASA Astrophysics Data System (ADS)

    Chen, H.; Yan, P.; Xiao, Q.; Wang, Y.; Gong, M.

    2012-09-01

    Based on semiconductor diode seeded multi-stage cascaded fiber amplifiers, we have obtained 88-W average power of a 1063-nm laser with high repetition rate of up to 1.5 MHz and a constant 2-ns pulse duration. No stimulated Brillouin scattering pulse or optical damage occurred although the maximum pulse peak power has exceeded 112 kW. The output laser exhibits excellent beam quality (M2x = 1.24 and M2y = 1.18), associated with a spectral line width as narrow as 0.065 nm (FWHM). Additionally, we demonstrate high polarization extinction ratio of 18.4 dB and good pulse stabilities superior to 1.6 % (RMS).

  6. Innovative fiber-laser architecture-based compact wind lidar

    NASA Astrophysics Data System (ADS)

    Prasad, Narasimha S.; Tracy, Allen; Vetorino, Steve; Higgins, Richard; Sibell, Russ

    2016-03-01

    This paper describes an innovative, compact and eyesafe coherent lidar system developed for use in wind and wake vortex sensing applications. This advanced lidar system is field ruggedized with reduced size, weight, and power consumption (SWaP) configured based on an all-fiber and modular architecture. The all-fiber architecture is developed using a fiber seed laser that is coupled to uniquely configured fiber amplifier modules and associated photonic elements including an integrated 3D scanner. The scanner provides user programmable continuous 360 degree azimuth and 180 degree elevation scan angles. The system architecture eliminates free-space beam alignment issues and allows plug and play operation using graphical user interface software modules. Besides its all fiber architecture, the lidar system also provides pulsewidth agility to aid in improving range resolution. Operating at 1.54 microns and with a PRF of up to 20 KHz, the wind lidar is air cooled with overall dimensions of 30" x 46" x 60" and is designed as a Class 1 system. This lidar is capable of measuring wind velocities greater than 120 +/- 0.2 m/s over ranges greater than 10 km and with a range resolution of less than 15 m. This compact and modular system is anticipated to provide mobility, reliability, and ease of field deployment for wind and wake vortex measurements. The current lidar architecture is amenable for trace gas sensing and as such it is being evolved for airborne and space based platforms. In this paper, the key features of wind lidar instrumentation and its functionality are discussed followed by results of recent wind forecast measurements on a wind farm.

  7. Multimode fiber laser beam cleanup based on stochastic parallel gradient descent algorithm

    NASA Astrophysics Data System (ADS)

    Zhao, Hai-Chuan; Ma, Hao-Tong; Zhou, Pu; Wang, Xiao-Lin; Ma, Yan-Xing; Li, Xiao; Xu, Xiao-Jun; Zhao, Yi-Jun

    2011-01-01

    We present experimental research on multimode fiber laser beam cleanup based on a stochastic parallel gradient descent (SPGD) algorithm. The multimode laser is obtained by injecting a 1064 nm central wavelength single mode fiber laser into a multimode fiber and the system is setup by using phase only liquid crystal spatial light modulators (LC-SLM). The quality evaluation function is increased by a factor of 10.5 and 65% of the laser energy is encircled in the central lobe when the system evolves from open-loop into close-loop state. Experimental results indicate the feasibility of the multimode fiber laser beam cleanup by adaptive optics (AO).

  8. Optical Frequency Comb Generation based on Erbium Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Droste, Stefan; Ycas, Gabriel; Washburn, Brian R.; Coddington, Ian; Newbury, Nathan R.

    2016-06-01

    Optical frequency combs have revolutionized optical frequency metrology and are being actively investigated in a number of applications outside of pure optical frequency metrology. For reasons of cost, robustness, performance, and flexibility, the erbium fiber laser frequency comb has emerged as the most commonly used frequency comb system and many different designs of erbium fiber frequency combs have been demonstrated. We review the different approaches taken in the design of erbium fiber frequency combs, including the major building blocks of the underlying mode-locked laser, amplifier, supercontinuum generation and actuators for stabilization of the frequency comb.

  9. Laser based microstructuring of polymer optical fibers for sensors optimization

    NASA Astrophysics Data System (ADS)

    Athanasekos, Loukas; Vasileiadis, Miltiadis; El Sachat, Alexandros; Vainos, Nikolaos A.; Riziotis, Christos

    2015-03-01

    Microstructuring of Polymer Optical Fibers-POF through surface modification with UV excimer laser radiation has been performed and studied. The laser modified surface cavities on fibers act as material receptors of exact volume allowing highly controllable and repeatable structures. The effect of Laser writing conditions on different etching characteristics of cladding and core materials of the fibres are presented. Ablated structures on the fibres are examined for optimised sensors' response characteristics. As a case study humidity and ammonia sensors are demonstrated by employing sensitive block copolymer materials on suitably micromachined segments of fibres.

  10. Mode-locked fiber laser based on chalcogenide microwires.

    PubMed

    Al-Kadry, Alaa; El Amraoui, Mohammed; Messaddeq, Younès; Rochette, Martin

    2015-09-15

    We report the first mode-locked fiber laser using a chalcogenide microwire as the nonlinear medium. The laser is passively mode-locked with nonlinear polarization rotation and can be adjusted for the emission of solitons or noise-like pulses. The use of the microwire leads to a mode-locking threshold at the microwatt level and shortens the cavity length by 4 orders of magnitude with respect to other lasers of its kind. The controlled birefringence of the microwire, combined with a linear polarizer in the cavity, enables multiwavelength laser operation with tunable central wavelength, switchable wavelength separation, and a variable number of laser wavelengths. PMID:26371923

  11. Mode-locked fiber laser based on chalcogenide microwires.

    PubMed

    Al-Kadry, Alaa; El Amraoui, Mohammed; Messaddeq, Younès; Rochette, Martin

    2015-09-15

    We report the first mode-locked fiber laser using a chalcogenide microwire as the nonlinear medium. The laser is passively mode-locked with nonlinear polarization rotation and can be adjusted for the emission of solitons or noise-like pulses. The use of the microwire leads to a mode-locking threshold at the microwatt level and shortens the cavity length by 4 orders of magnitude with respect to other lasers of its kind. The controlled birefringence of the microwire, combined with a linear polarizer in the cavity, enables multiwavelength laser operation with tunable central wavelength, switchable wavelength separation, and a variable number of laser wavelengths.

  12. A fiber-laser-based stimulated Raman scattering spectral microscope

    NASA Astrophysics Data System (ADS)

    Nose, Keisuke; Ozeki, Yasuyuki; Kishi, Tatsuya; Sumimura, Kazuhiko; Kanematsu, Yasuo; Itoh, Kazuyoshi

    2013-02-01

    Stimulated Raman scattering (SRS) spectral microscopy is a powerful technique for label-free biological imaging because it allows us to distinguish chemical species with overlapping Raman bands. Here we present an SRS spectral microscope based only on fiber lasers (FL's), which offer the possibilities of downsizing and simplification of the system. A femtosecond figure-8 Er-FL at a repetition rate of 54.4 MHz is used to generate pump pulses. After amplified by an Er doped fiber amplifier, Er-FL pulses are spectrally compressed to 2-ps second harmonic pulses. For generating Stokes pulses, a femtosecond Yb-FL pulses at a repetition rate of 27.2 MHz is used. Then these lasers are synchronized by a phase locked loop, which consists of a two-photon absorption photodetector, a loop filter, a phase modulator in the Er- FL cavity, and a piezo electric transducer in the Yb-FL cavity. The intensity noise of pump pulses is reduced by the collinear balanced detection (CBD) technique based on delay-and-add fiber lines. Experimentally, we confirmed that the intensity noise level of probe pulses was close to the shot noise limit. The Stokes pulses are introduced to a wavelength tunable band pass filter (BPF), which consists of a galvanomirror scanner, a 4-f optical system, a reflection grating, and a collimator. This system is able to scan the wavenumber from 2850 cm-1 to 3100 cm-1 by tuning the BPF. We succeeded in the spectral imaging of a mixture of polystyrene beads and poly(methyl methacrylate) beads.

  13. Nondestructive thickness measurement system for multiple layers of paint based on femtosecond fiber laser technologies

    NASA Astrophysics Data System (ADS)

    Sudo, Masaaki; Takayanagi, Jun; Ohtake, Hideyuki

    2016-11-01

    Because optical fiber-based optical systems are generally robust against external interference, they can be used as reliable systems in industrial applications in various fields. This paper describes fiber lasers generating femtosecond pulses that use optical fibers as gain media and optical paths. Additionally, the nondestructive paint multilayer thickness measurement of automotive parts using terahertz waves generated and detected by femtosecond fiber laser systems was conducted.

  14. Nondestructive thickness measurement system for multiple layers of paint based on femtosecond fiber laser technologies

    NASA Astrophysics Data System (ADS)

    Sudo, Masaaki; Takayanagi, Jun; Ohtake, Hideyuki

    2016-09-01

    Because optical fiber-based optical systems are generally robust against external interference, they can be used as reliable systems in industrial applications in various fields. This paper describes fiber lasers generating femtosecond pulses that use optical fibers as gain media and optical paths. Additionally, the nondestructive paint multilayer thickness measurement of automotive parts using terahertz waves generated and detected by femtosecond fiber laser systems was conducted.

  15. 2μm single frequency fiber laser based on thulium-doped silica fiber

    NASA Astrophysics Data System (ADS)

    Fu, Shijie; Shi, Wei; Lin, Jichao; Fang, Qiang; Sheng, Quan; Zhang, Haiwei; Wen, Jinwei; Yao, Jianquan

    2016-03-01

    Single-frequency fiber laser operating at 1950 nm has been demonstrated in an all-fiber distributed Bragg reflection (DBR) laser cavity by using a 1.9-cm commercial available Thulium-doped silica fiber, for the first time. The laser was pumped by a 793-nm single-mode diode laser and had a threshold pump power of 75 mW. The maximum output power of the single longitudinal mode laser was 18 mW and the slope efficiency with respect to the launched pump power was 11%. Moreover, the linewidth and relative intensity noise (RIN) at different pump power has been measured and analyzed. The successful demonstration with the Thulium-doped silica fiber used here is considered to further promote the commercialization of single frequency fiber laser at 2 μm.

  16. Switchable multiwavelength erbium doped fiber laser based on a nonlinear optical loop mirror incorporating multiple fiber Bragg gratings.

    PubMed

    Tran, Thi Van Anh; Lee, Kwanil; Lee, Sang Bae; Han, Young-Geun

    2008-02-01

    We propose and experimentally demonstrate a switchable multiwavelength erbium doped fiber laser based on a highly nonlinear dispersion shifted fiber and multiple fiber Bragg gratings. A nonlinear optical loop mirror based on a highly nonlinear dispersion shifted fiber is implemented in the ring laser cavity to stabilize the multiwavelength output at room temperature. Multiple fiber Bragg gratings with the wavelength spacing of 0.8 nm are connected with an arrayed waveguide grating to establish a multichannel filter. The high quality of the multiwavelength output with a high extinction ratio of ~60 dB and high output flatness of ~0.5 dB is realized. The nonlinear polarization rotation based on the nonlinear optical loop mirror can provide the switching performance of the proposed multiwavelength fiber laser. The lasing wavelength can be switched individually by controlling the polarization controller and the cavity loss.

  17. A switchable dual-wavelength fiber laser based on asymmetric fiber Bragg grating Fabry-Perot cavity with a SESAM

    NASA Astrophysics Data System (ADS)

    Huang, Kaiqiang; Li, Qi; Chen, Haiyan

    2016-04-01

    A switchable dual-wavelength fiber laser with an asymmetric fiber Bragg grating (FBG)-Fabry-Perot (FP) cavity based a semiconductor saturable absorber mirror (SESAM) is proposed and experimentally demonstrated. The proof of concept device consists of a FGB laser with an asymmetric FBG-FP cavity, a SESAM as mode loss modulator, and a intracavity FBG as wavelength selector by changing its operation temperature. The results demonstrate the new concept of dual-wavelength fiber laser based SESAM with asymmetric FBG-FP cavity and the technical feasibility.

  18. Fiber Lasers and Amplifiers for Space-based Science and Exploration

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Stephen, Mark A.; Chen, Jeffrey R.; Coyle, Barry; Numata, Kenji; Camp, Jordan; Abshire, James B.; Allan, Graham R.; Li, Steven X.; Riris, Haris

    2012-01-01

    We present current and near-term uses of high-power fiber lasers and amplifiers for NASA science and spacecraft applications. Fiber lasers and amplifiers offer numerous advantages for the deployment of instruments on exploration and science remote sensing satellites. Ground-based and airborne systems provide an evolutionary path to space and a means for calibration and verification of space-borne systems. NASA fiber-laser-based instruments include laser sounders and lidars for measuring atmospheric carbon dioxide, oxygen, water vapor and methane and a pulsed or pseudo-noise (PN) code laser ranging system in the near infrared (NIR) wavelength band. The associated fiber transmitters include high-power erbium, ytterbium, and neodymium systems and a fiber laser pumped optical parametric oscillator. We discuss recent experimental progress on these systems and instrument prototypes for ongoing development efforts.

  19. Spectrum-, pulsewidth-, and wavelength-switchable all-fiber mode-locked Yb laser with fiber based birefringent filter.

    PubMed

    Fedotov, Y S; Kobtsev, S M; Arif, R N; Rozhin, A G; Mou, C; Turitsyn, S K

    2012-07-30

    We examined methods of controlling the pulse duration, spectral width and wavelength of the output from an all-fiber Yb laser mode-locked by carbon nanotubes. It is shown that a segment of polarization maintaining (PM) fiber inserted into a standard single mode fiber based laser cavity can function as a spectral selective filter. Adjustment of the length of the PM fiber from 1 to 2 m led to a corresponding variation in the pulse duration from 2 to 3.8 ps, the spectral bandwidth of the laser output changes from 0.15 to 1.26 nm. Laser output wavelength detuning within up to 5 nm was demonstrated with a fixed length of the PM fiber by adjustment of the polarization controller. PMID:23038330

  20. Multi-parameter sensor based on random fiber lasers

    NASA Astrophysics Data System (ADS)

    Xu, Yanping; Zhang, Mingjiang; Lu, Ping; Mihailov, Stephen; Bao, Xiaoyi

    2016-09-01

    We demonstrate a concept of utilizing random fiber lasers to achieve multi-parameter sensing. The proposed random fiber ring laser consists of an erbium-doped fiber as the gain medium and a random fiber grating as the feedback. The random feedback is effectively realized by a large number of reflections from around 50000 femtosecond laser induced refractive index modulation regions over a 10cm standard single mode fiber. Numerous polarization-dependent spectral filters are formed and superimposed to provide multiple lasing lines with high signal-to-noise ratio up to 40dB, which gives an access for a high-fidelity multi-parameter sensing scheme. The number of sensing parameters can be controlled by the number of the lasing lines via input polarizations and wavelength shifts of each peak can be explored for the simultaneous multi-parameter sensing with one sensing probe. In addition, the random grating induced coupling between core and cladding modes can be potentially used for liquid medical sample sensing in medical diagnostics, biology and remote sensing in hostile environments.

  1. Fiber-Based Lasers as an Option for GRACE Follow-On Light Source

    NASA Technical Reports Server (NTRS)

    Camp, Jordan

    2010-01-01

    Fiber based lasers offer a number of attractive characteristics for space application: state of the art laser technology, leverage of design and reliability from the substantial investments of the telecon industry, and convenient redundancy of higher risk components through fiber splicing. At NASA/Goddard we are currently investigating three GFO fiber-based laser options: a fiber oscillator built in our laboratory; an effort to space qualify a commercial design that uses a proprietary high-gain fiber cavity; and the space qualification of a promising new commercial external cavity laser, notable for its low-mass, compact design. In my talk I will outline these efforts, and suggest that the GFO Project may soon have the option of a US laser vendor for its light source.

  2. Ultrafast fiber lasers based on self-similar pulse evolution: a review of current progress.

    PubMed

    Chong, Andy; Wright, Logan G; Wise, Frank W

    2015-11-01

    Self-similar fiber oscillators are a relatively new class of mode-locked lasers. In these lasers, the self-similar evolution of a chirped parabolic pulse in normally-dispersive passive, active, or dispersion-decreasing fiber (DDF) is critical. In active (gain) fiber and DDF, the novel role of local nonlinear attraction makes the oscillators fundamentally different from any mode-locked lasers considered previously. In order to reconcile the spectral and temporal expansion of a pulse in the self-similar segment with the self-consistency required by a laser cavity's periodic boundary condition, several techniques have been applied. The result is a diverse range of fiber oscillators which demonstrate the exciting new design possibilities based on the self-similar model. Here, we review recent progress on self-similar oscillators both in passive and active fiber, and extensions of self-similar evolution for surpassing the limits of rare-earth gain media. We discuss some key remaining research questions and important future directions. Self-similar oscillators are capable of exceptional performance among ultrashort pulsed fiber lasers, and may be of key interest in the development of future ultrashort pulsed fiber lasers for medical imaging applications, as well as for low-noise fiber-based frequency combs. Their uniqueness among mode-locked lasers motivates study into their properties and behaviors and raises questions about how to understand mode-locked lasers more generally.

  3. Ultrafast fiber lasers based on self-similar pulse evolution: a review of current progress

    PubMed Central

    Chong, Andy; Wright, Logan G; Wise, Frank W

    2016-01-01

    Self-similar fiber oscillators are a relatively new class of mode-locked lasers. In these lasers, the self-similar evolution of a chirped parabolic pulse in normally-dispersive passive, active, or dispersion-decreasing fiber (DDF) is critical. In active (gain) fiber and DDF, the novel role of local nonlinear attraction makes the oscillators fundamentally different from any mode-locked lasers considered previously. In order to reconcile the spectral and temporal expansion of a pulse in the self-similar segment with the self-consistency required by a laser cavity's periodic boundary condition, several techniques have been applied. The result is a diverse range of fiber oscillators which demonstrate the exciting new design possibilities based on the self-similar model. Here, we review recent progress on self-similar oscillators both in passive and active fiber, and extensions of self-similar evolution for surpassing the limits of rare-earth gain media. We discuss some key remaining research questions and important future directions. Self-similar oscillators are capable of exceptional performance among ultrashort pulsed fiber lasers, and may be of key interest in the development of future ultrashort pulsed fiber lasers for medical imaging applications, as well as for low-noise fiber-based frequency combs. Their uniqueness among mode-locked lasers motivates study into their properties and behaviors and raises questions about how to understand mode-locked lasers more generally. PMID:26496377

  4. Tunable multi-wavelength fiber lasers based on an Opto-VLSI processor and optical amplifiers.

    PubMed

    Xiao, Feng; Alameh, Kamal; Lee, Yong Tak

    2009-12-01

    A multi-wavelength tunable fiber laser based on the use of an Opto-VLSI processor in conjunction with different optical amplifiers is proposed and experimentally demonstrated. The Opto-VLSI processor can simultaneously select any part of the gain spectrum from each optical amplifier into its associated fiber ring, leading to a multiport tunable fiber laser source. We experimentally demonstrate a 3-port tunable fiber laser source, where each output wavelength of each port can independently be tuned within the C-band with a wavelength step of about 0.05 nm. Experimental results demonstrate a laser linewidth as narrow as 0.05 nm and an optical side-mode-suppression-ratio (SMSR) of about 35 dB. The demonstrated three fiber lasers have excellent stability at room temperature and output power uniformity less than 0.5 dB over the whole C-band.

  5. Tunable and switchable dual-wavelength erbium-doped fiber laser based on in-line tapered fiber filters

    NASA Astrophysics Data System (ADS)

    Tong, Zheng-rong; Yang, He; Cao, Ye

    2016-07-01

    A tunable and switchable dual-wavelength erbium-doped fiber laser (EDFL) based on all-fiber single-mode tapered fiber structure has been demonstrated. By adjusting the variable optical attenuator (VOA), the laser can be switched between the single-wavelength mode and the dual-wavelength mode. When the temperature applied on the tapered fiber structure varies, the pass-band varies and the wavelength of the output laser shifts correspondingly. When the temperature changes from 30 °C to 180 °C, the central wavelength of the EDFL generated by branch A shifts from 1 550.7 nm to 1 560.3 nm, while that of branch B shifts from 1 530.8 nm to 1 540.4 nm, indicating the wavelength interval is tunable. These advantages enable this laser to be a potential candidate for high-capacity wavelength division multiplexing systems and mechanical sensors.

  6. Broadly tunable dual-wavelength erbium-doped ring fiber laser based on a high-birefringence fiber loop mirror

    NASA Astrophysics Data System (ADS)

    Sun, H. B.; Liu, X. M.; Gong, Y. K.; Li, X. H.; Wang, L. R.

    2010-02-01

    A broadly tunable dual-wavelength erbium-doped ring fiber laser based on a high-birefringence fiber loop mirror (HiBi-FLM) and a polarization controller is demonstrated experimentally. The measured transmission spectrum of HiBi-FLM covers a wide range from 1525 to 1575 nm. The wavelength of proposed laser can be flexibly tunable during this range of ˜50 nm by adjusting the polarization controller. In addition, the spacing of two wavelengths is adjustable by changing the length of HiBi fiber. The dual-wavelength lasers with the HiBi fiber length of 1 and 2 m are experimentally demonstrated and compared. The experimental results show that the proposed laser can stably operate on two wavelengths simultaneously at room temperature, and the output peak power variation is about 0.5 dB during 40 min.

  7. Mode-locked fiber/waveguide lasers based on a fiber taper embedded in carbon nanotubes/polymer composite

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Khanh, Kieu; Honkanen, Seppo; Kueppers, Franko

    2008-04-01

    We generated 2 nJ, ~690 fs pulses with 10 MHz repetition rate from a linear cavity mode-locked Er 3+-doped fiber laser with a fiber taper embedded in carbon nanotubes (CNTs)/polymer composite. Evanescent field out of the taper section can interact with CNTs to see saturation of absorption. With the fiber based saturable absorber this laser has simple and robust all-fiber configuration comparing to traditional linear cavity mode-locked lasers with semiconductor saturable absorbers. In addition, we have demonstrated a mode-locked ring laser, with a similar saturable absorber, by using an ion-exchanged Er 3+-Yb 3+-codoped planar waveguide as the gain medium.

  8. Single-frequency fiber laser at 1950 nm based on thulium-doped silica fiber.

    PubMed

    Fu, Shijie; Shi, Wei; Lin, Jichao; Fang, Qiang; Sheng, Quan; Zhang, Haiwei; Wen, Jinwei; Yao, Jianquan

    2015-11-15

    A single-frequency fiber laser operating at 1950 nm has been demonstrated in an all-fiber distributed Bragg reflection laser cavity by using a 1.9 cm commercially available thulium-doped silica fiber, for the first time, to the best of our knowledge. The laser was pumped by a 793 nm single-mode diode laser and had a threshold pump power of 75 mW. The maximum output power of the single longitudinal mode laser was 18 mW and the slope efficiency with respect to the launched pump power was 11%. Moreover, the linewidth and relative intensity noise at different pump power have been measured and analyzed. PMID:26565855

  9. Wavelength-switchable fiber laser based on few-mode fiber filter with core-offset structure

    NASA Astrophysics Data System (ADS)

    Qi, Yanhui; Kang, Zexin; Sun, Jiang; Ma, Lin; Jin, Wenxing; Lian, Yudong; Jian, Shuisheng

    2016-07-01

    We propose a wavelength-switchable erbium-doped fiber ring laser based on the few-mode fiber filter with core-offset structure. The filter is constructed by splicing a section of few-mode fiber with two segments of single mode fiber. Meanwhile, the excited modes are effectively selected by controlling the core-offset splicing carefully. The novel filter is based on the interference between fundamental mode and LP11 mode. The single-, dual-, triple- and quad-wavelength fiber laser is accomplished by adjusting the states of polarization controller at room temperature. The principle of operation is mainly based on the saturated spectral hole-burning effect and the balance between the gain and loss in the cavity.

  10. All-fiber passively mode-locked laser based on a chiral fiber grating.

    PubMed

    Du, Yueqing; Shu, Xuewen; Xu, Zuowei

    2016-01-15

    A novel passively mode-locked all-fiber laser using a chiral fiber grating as a polarization-selective element is demonstrated for the first time, to the best of our knowledge. The chiral fiber grating serves as a key component to form an artificial saturable absorber to realize mode locking through nonlinear polarization rotation in the cavity. The laser generates stable short pulses with energy of 0.34 nJ, a fundamental repetition rate of 3.27 MHz, and an FWHM bandwidth of 28 nm. We also show that harmonic mode-locked pulse trains of different orders can be obtained by increasing the pump power.

  11. Single-frequency Yb-doped fiber laser with distributed feedback based on a random FBG

    NASA Astrophysics Data System (ADS)

    Abdullina, S. R.; Vlasov, A. A.; Lobach, I. A.; Belai, O. V.; Shapiro, D. A.; Babin, S. A.

    2016-07-01

    Single-frequency operation of a 1.03 μm fiber laser with random distributed feedback (RDFB) is demonstrated. The laser cavity is based on a 4 cm long fiber Bragg grating (FBG) consisting of 10 homogeneous subgratings with random phase and amplitude of refractive index modulation inscribed in a polarization maintaining (PM) Yb-doped fiber. Such RDFB laser generates single longitudinal mode with output power up to 25 mW, which is 3.5 times higher than that for a DFB laser based on regular π-shifted FBG of the same length in the same fiber. The single-frequency linewidth is measured to be  <100 kHz in both cases. The observed difference of the DFB and RDFB lasers is confirmed by numerical simulation showing different longitudinal distribution of intra-cavity radiation in these cases, analogous to those in the experiment.

  12. Fiber distributed feedback laser

    NASA Technical Reports Server (NTRS)

    Elachi, C.; Evans, G. A.; Yeh, C. (Inventor)

    1976-01-01

    Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs.

  13. 25 W Raman-fiber-amplifier-based 589 nm laser for laser guide star.

    PubMed

    Feng, Yan; Taylor, Luke R; Calia, Domenico Bonaccini

    2009-10-12

    We report on a 25 W continuous wave narrow linewidth (< 2.3 MHz) 589 nm laser by efficient (> 95%) coherent beam combination of two narrow linewidth (< 1.5 MHz) Raman fiber amplifiers with a Mach-Zehnder interferometer scheme and frequency doubling in an external resonant cavity with an efficiency of 86%. The results demonstrate the narrow linewidth Raman fiber amplifier technology as a promising solution for developing laser for sodium laser guide star adaptive optics. PMID:20372636

  14. 25 W Raman-fiber-amplifier-based 589 nm laser for laser guide star.

    PubMed

    Feng, Yan; Taylor, Luke R; Calia, Domenico Bonaccini

    2009-10-12

    We report on a 25 W continuous wave narrow linewidth (< 2.3 MHz) 589 nm laser by efficient (> 95%) coherent beam combination of two narrow linewidth (< 1.5 MHz) Raman fiber amplifiers with a Mach-Zehnder interferometer scheme and frequency doubling in an external resonant cavity with an efficiency of 86%. The results demonstrate the narrow linewidth Raman fiber amplifier technology as a promising solution for developing laser for sodium laser guide star adaptive optics.

  15. Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings.

    PubMed

    Tian, Jiajun; Zhang, Qi; Han, Ming

    2013-03-11

    Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiber-optic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasi-distributed biochemical fiber-optic sensing.

  16. Tunable multiwavelength erbium-doped fiber laser based on nonlinear optical loop mirror and birefringence fiber filter

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Quan, Mingran; Tian, Jiajun; Yao, Yong

    2015-05-01

    A tunable multiwavelength erbium-doped fiber laser (MWEDFL) based on nonlinear optical loop mirror (NOLM) and tunable birefringence fiber filter (BFF) is proposed and demonstrated. By combination of intensity-dependent loss modulation induced by NOLM and pump power adjustment, the proposed laser can achieve independent control over the number of lasing lines, without affecting other important characteristics such as channel spacing and peak location. In addition, the laser allows wavelength tuning with both the peak location and the spectral range of lasing lines controllable. Specifically, the peak location of lasing lines can be controlled to scan the whole spectral range between adjacent channels of comb filter by adjusting the BFF. Moreover, the spectral range of lasing lines can be controlled by adjusting NOLM. This tunable MWEDFL may be useful for fiber-optic communication and fiber-optic sensing.

  17. High power L-band mode-locked fiber laser based on topological insulator saturable absorber.

    PubMed

    Meng, Yichang; Semaan, Georges; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Luo, Zhi-Chao; Sanchez, Francois

    2015-09-01

    We demonstrate a passive mode-locked Er:Yb doped double-clad fiber laser using a microfiber-based topological insulator (Bi(2)Se(3)) saturable absorber (TISA). By optimizing the cavity loss and output coupling ratio, the mode-locked fiber laser can operate in L-band with high average output power. With the highest pump power of 5 W, 91st harmonic mode locking of soliton bunches with average output power of 308 mW was obtained. This is the first report that the TISA based erbium-doped fiber laser operating above 1.6 μm and is also the highest output power yet reported in TISA based passive mode-locked fiber laser.

  18. Fiber laser strain sensor based in the measurement of a Sagnac interferometer optical power spectrum

    NASA Astrophysics Data System (ADS)

    Durán Sánchez, M.; Álvarez Tamayo, R. I.; Pottiez, O.; Kuzin, E. A.; Ibarra-Escamilla, B.; Barcelata Pinzón, A.

    2014-06-01

    In this paper a linear cavity Erbium doped fiber (EDF) laser based in a fiber Bragg grating (FBG) and a fiber optical loop mirror with a high birefringence fiber in the loop (Hi-Bi FOLM) is used as a strain sensor. The Fabry-Perot cavity is formed by the FBG and the Hi-Bi FOLM, used as a measurement system of strain variations produced on the FBG, used as a strain sensor device. Usually, fiber laser sensor experimental setups determine the measured variable magnitude by using of an optical spectrum analyzer (OSA). Hi-Bi FOLM transmission spectrum wavelength displacement by fiber loop temperature variations measurement can be an attractive application exploiting the characteristics of FOLM transmission spectrum behavior due to Hi-Bi fiber loop temperature variations to determine the FBG strain applied through the maximal optical power monitoring by simple use of a photodetector and a temperature meter.

  19. Fiber Bragg grating Fabry-Perot cavity sensor based on pulse laser demodulation technique

    NASA Astrophysics Data System (ADS)

    Gao, Fangfang; Chen, Jianfeng; Liu, Yunqi; Wang, Tingyun

    2011-12-01

    We demonstrate a fiber laser sensing technique based on fiber Bragg grating Fabry-Perot (FBG-FP) cavity interrogated by pulsed laser, where short pulses generated from active mode-locked erbium-doped fiber ring laser and current modulated DFB laser are adopted. The modulated laser pulses launched into the FBG-FP cavity produce a group of reflected pulses. The optical loss in the cavity can be determined from the power ratio of the first two pulses reflected from the cavity. This technique does not require high reflectivity FBGs and is immune to the power fluctuation of the light source. Two short pulse laser sources were compared experimentally with each other on pulse width, pulse stability, pulse chirp and sensing efficiency.

  20. Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems

    NASA Technical Reports Server (NTRS)

    Richards, Lance; Parker, Allen; Chan, Patrick

    2014-01-01

    The objective of this task is to investigate, develop, and demonstrate a low-cost swept lasing light source for NASA DFRC's fiber optics sensing system (FOSS) to perform structural health monitoring on current and future aerospace vehicles. This is the regular update of the Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems website.

  1. High-power soliton fiber laser based on pulse width control with chirped fiber Bragg gratings

    SciTech Connect

    Fermann, M.E.; Sugden, K.; Bennion, I.

    1995-01-15

    Chirped fiber Bragg gratings control the pulse width and energy in Kerr mode-locked erbium fiber soliton lasers. We create high-energy pulses by providing large amounts of excessive negative dispersion, which increases the pulse width while keeping the nonlinearity of the cavity constant. With a chirped fiber grating of 3.4-ps{sup 2} dispersion, 3-ps pulses with an energy content higher than 1 nJ are generated at a repetition rate of 27 MHz. By controlling the polarization state in the cavity, we obtain a tuning range from 1.550 to 1.562 {mu}m.

  2. All-fiber tunable laser based on an acousto-optic tunable filter and a tapered fiber.

    PubMed

    Huang, Ligang; Song, Xiaobo; Chang, Pengfa; Peng, Weihua; Zhang, Wending; Gao, Feng; Bo, Fang; Zhang, Guoquan; Xu, Jingjun

    2016-04-01

    An all-fiber tunable laser was fabricated based on an acousto-optic tunable filter and a tapered fiber. The structure was of a high signal-to-noise ratio, therefore, no extra gain flattening was needed in the laser. In the experiment, the wavelength of the laser could be tuned from 1532.1 nm to 1570.4 nm with a 3-dB bandwidth of about 0.2 nm. Given enough nonlinearity in the laser cavity, it could also generate a sliding-frequency pulse train. The laser gains advantages of fast tuning and agility in pulse generation, and its simple structure is low cost for practical applications. PMID:27137035

  3. Cable television monitoring system based on fiber laser and FBG sensor

    NASA Astrophysics Data System (ADS)

    Peng, Peng-Chun; Huang, Jun-Han; Wu, Shin-Shian; Yang, Wei-Yuan; Shen, Po-Tso

    2015-05-01

    We propose and experimentally demonstrate a cable television monitoring system based on a linear-cavity fiber laser and fiber Bragg grating (FBG) sensors. The linear-cavity fiber laser comprises a hybrid amplifier with an erbium-doped fiber amplifier and a semiconductor optical amplifier, a fiber loop mirror with a polarization controller and an optical coupler as a cavity mirror, and the FBG sensors acting as another cavity mirrors. Experimental results showed the feasibility of the monitoring system with sufficient of signal-to-noise ratio over 30 dB and stable output power, and the link of cable television signals on fiber link can monitored in real time. Excellent performances of carrier-to-noise ratio after long-distance transmission are obtained for cable television applications.

  4. Investigation of Fiber Optics Based Phased Locked Diode Lasers

    NASA Technical Reports Server (NTRS)

    Burke, Paul D.; Gregory, Don A.

    1997-01-01

    Optical power beaming requires a high intensity source and a system to address beam phase and location. A synthetic aperture array of phased locked sources can provide the necessary power levels as well as a means to correct for phase errors. A fiber optic phase modulator with a master oscillator and power amplifier (MOPA) using an injection-locking semiconductor optical amplifier has proven to be effective in correcting phase errors as large as 4pi in an interferometer system. Phase corrections with the piezoelectric fiber stretcher were made from 0 - 10 kHz, with most application oriented corrections requiring only 1 kHz. The amplifier did not lose locked power output while the phase was changed, however its performance was below expectation. Results of this investigation indicate fiber stretchers and amplifiers can be incorporated into a MOPA system to achieve successful earth based power beaming.

  5. Multichannel laser-fiber vibrometer

    NASA Astrophysics Data System (ADS)

    Dudzik, Grzegorz; Waz, Adam; Kaczmarek, Pawel; Antonczak, Arkadiusz; Sotor, Jaroslaw; Krzempek, Karol; Sobon, Grzegorz; Abramski, Krzysztof M.

    2013-01-01

    For the last few years we were elaborating the laser-fiber vibrometer working at 1550 nm. Our main stress was directed towards different aspects of research: analysis of scattered light, efficient photodetection, optimization of the fiber-free space interfaces and signal processing. As a consequence we proposed the idea of a multichannel fiber vibrometer based on well developed telecommunication technique - Wavelength Division Multiplexing (WDM). One of the most important parts of a fiber-laser vibrometer is demodulation electronic section. The distortion, nonlinearity, offset and added noise of measured signal come from electronic circuits and they have direct influence on finale measuring results. We present the results of finished project "Developing novel laser-fiber monitoring technologies to prevent environmental hazards from vibrating objects" where we have constructed a 4-channel WDM laser-fiber vibrometer.

  6. Multi-wavelength erbium-doped fiber laser based on random distributed feedback

    NASA Astrophysics Data System (ADS)

    Liu, Yuanyang; Dong, Xinyong; Jiang, Meng; Yu, Xia; Shum, Ping

    2016-09-01

    We experimentally demonstrated a multi-wavelength erbium-doped fiber laser based on random distributed feedback via a 20-km-long single-mode fiber together with a Sagnac loop mirror. The number of channels can be modulated from 2 to 8 at room temperature when the pump power is changed from 30 to 180 mW, indicating that wavelength competition caused by homogenous gain broadening of erbium-doped fiber is significantly suppressed. Other advantages of the laser include low cost, low-threshold pump power and simple fabrication.

  7. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  8. Electrically tunable fiber-integrated Yb-doped laser covering 74 nm based on a fiber Bragg grating array

    NASA Astrophysics Data System (ADS)

    Tiess, T.; Rothhardt, M.; Chojetzki, C.; Jäger, M.; Bartelt, H.

    2015-03-01

    Fiber lasers provide the foundation to combine an excellent beam quality in single mode operation with a robust and highly efficient design. Based on fiber-integrated configurations, they are employed in many different applications ranging from industry over research to medical technology. However, there is lots of potential to approach even new fields of applications e.g. in spectroscopy based on tunable systems with an adjustable emission wavelength. We present a novel tuning concept for pulsed fiber-integrated laser systems using an array of fiber Bragg gratings (FBGs) as discrete spectral filter. Based on stacking many standard FBGs, the bandwidth and filter properties are easy to scale by increasing the number of gratings allowing huge tuning ranges as well as tailored tuning characteristics. In this work, we demonstrate the potential of this electrically controlled tuning concept. Using an Ytterbium (Yb)-doped fiber laser, we investigate the general tuning characteristics. With variable pulse durations in the nanosecond regime, we demonstrate high signal contrast (~45 dB), excellent wavelength stability and narrow linewidth (<15 GHz). In order to highlight the great spectral freedom, a tuning range of 74 nm in the Yb band is realized which, to the best of our knowledge, is the largest bandwidth reported based on a monolithic filter design.

  9. Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Abshire, James B.

    2010-01-01

    A fiber-based laser transmitter has been designed for active remote-sensing spectroscopy. The transmitter uses a master-oscillator-power-amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled nonlinear crystal. The utility of this single-frequency, wavelength-tunable, power-scalable laser has been demonstrated in a spectroscopic measurement of the diatomic oxygen A-band.

  10. Thulium-doped all-fiber mode-locked laser based on NPR and 45°-tilted fiber grating.

    PubMed

    Li, Jianfeng; Yan, Zhijun; Sun, Zhongyuan; Luo, Hongyu; He, Yulian; Li, Zhuo; Liu, Yong; Zhang, Lin

    2014-12-15

    A nonlinear polarization rotation based all-fiber passively mode-locked Tm³⁺-doped fiber laser is demonstrated by using a 45° tilted fiber grating (TFG) as an in-line polarizer. The 45° TFG centered at 2000 nm with polarization dependent loss (PDL) of >12 dB at 1850 nm~2150 nm range was UV inscribed for the first time in SM28 fiber using a 244 nm Ar⁺ continuous wave laser and a phase mask with 25 mm long uniform pitch and titled period pattern of 33.7° with respect to the fiber axis. Stable soliton pulses centered at 1992.7 nm with 2.02 nm FWHM bandwidth were produced at a repetition rate of 1.902 MHz with pulse duration of 2.2 ps and pulse energy of 74.6 pJ. As increased pump power, the laser also can operate at noise-like regime with 18.1 nm FWHM bandwidth and pulse energy of up to 250.1 nJ. Using the same 45° TFG, both stable soliton and noise-like mode-locking centered at ~1970 nm and ~2050 nm, were also achieved by shortening and extending the length of Tm³⁺-doped fiber, respectively, exhibiting advantages of broadband and low insertion loss at 2 µm band. PMID:25607051

  11. Thulium-doped all-fiber mode-locked laser based on NPR and 45°-tilted fiber grating.

    PubMed

    Li, Jianfeng; Yan, Zhijun; Sun, Zhongyuan; Luo, Hongyu; He, Yulian; Li, Zhuo; Liu, Yong; Zhang, Lin

    2014-12-15

    A nonlinear polarization rotation based all-fiber passively mode-locked Tm³⁺-doped fiber laser is demonstrated by using a 45° tilted fiber grating (TFG) as an in-line polarizer. The 45° TFG centered at 2000 nm with polarization dependent loss (PDL) of >12 dB at 1850 nm~2150 nm range was UV inscribed for the first time in SM28 fiber using a 244 nm Ar⁺ continuous wave laser and a phase mask with 25 mm long uniform pitch and titled period pattern of 33.7° with respect to the fiber axis. Stable soliton pulses centered at 1992.7 nm with 2.02 nm FWHM bandwidth were produced at a repetition rate of 1.902 MHz with pulse duration of 2.2 ps and pulse energy of 74.6 pJ. As increased pump power, the laser also can operate at noise-like regime with 18.1 nm FWHM bandwidth and pulse energy of up to 250.1 nJ. Using the same 45° TFG, both stable soliton and noise-like mode-locking centered at ~1970 nm and ~2050 nm, were also achieved by shortening and extending the length of Tm³⁺-doped fiber, respectively, exhibiting advantages of broadband and low insertion loss at 2 µm band.

  12. Laminar-Turbulent Transition in Raman Fiber Lasers: A First Passage Statistics Based Analysis

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Amit K.; Nasiev, Diar; Sugavanam, Srikanth; Tarasov, Nikita; Churkin, Dmitry V.

    2016-06-01

    Loss of coherence with increasing excitation amplitudes and spatial size modulation is a fundamental problem in designing Raman fiber lasers. While it is known that ramping up laser pump power increases the amplitude of stochastic excitations, such higher energy inputs can also lead to a transition from a linearly stable coherent laminar regime to a non-desirable disordered turbulent state. This report presents a new statistical methodology, based on first passage statistics, that classifies lasing regimes in Raman fiber lasers, thereby leading to a fast and highly accurate identification of a strong instability leading to a laminar-turbulent phase transition through a self-consistently defined order parameter. The results have been consistent across a wide range of pump power values, heralding a breakthrough in the non-invasive analysis of fiber laser dynamics.

  13. Laminar-Turbulent Transition in Raman Fiber Lasers: A First Passage Statistics Based Analysis

    PubMed Central

    Chattopadhyay, Amit K.; Nasiev, Diar; Sugavanam, Srikanth; Tarasov, Nikita; Churkin, Dmitry V.

    2016-01-01

    Loss of coherence with increasing excitation amplitudes and spatial size modulation is a fundamental problem in designing Raman fiber lasers. While it is known that ramping up laser pump power increases the amplitude of stochastic excitations, such higher energy inputs can also lead to a transition from a linearly stable coherent laminar regime to a non-desirable disordered turbulent state. This report presents a new statistical methodology, based on first passage statistics, that classifies lasing regimes in Raman fiber lasers, thereby leading to a fast and highly accurate identification of a strong instability leading to a laminar-turbulent phase transition through a self-consistently defined order parameter. The results have been consistent across a wide range of pump power values, heralding a breakthrough in the non-invasive analysis of fiber laser dynamics. PMID:27349282

  14. A Fiber Optic PD Sensor Using a Balanced Sagnac Interferometer and an EDFA-Based DOP Tunable Fiber Ring Laser

    PubMed Central

    Wang, Lutang; Fang, Nian; Wu, Chunxu; Qin, Haijuan; Huang, Zhaoming

    2014-01-01

    A novel fiber-optic acoustic sensor using an erbium-doped fiber amplifier (EDFA)-based fiber ring laser and a balanced Sagnac interferometer for acoustic sensing of the partial discharge (PD) in power transformers is proposed and demonstrated. As a technical background, an experimental investigation on how the variations of the fiber birefringence affect the sensor performances was carried out, and the results are discussed. The operation principles are described, and the relevant formulas are derived. The analytical results show that an EDFA-based fiber ring laser operating in chaotic mode can provide a degree of polarization (DOP) tunable light beam for effectively suppressing polarization fading noises. The balanced Sagnac interferometer can eliminate command intensity noises and enhance the signal-to-noise ratio (SNR). Furthermore, it inherently operates at the quadrature point of the response curve without any active stabilizations. Several experiments are conducted for evaluating the performances of the sensor system, as well as for investigating the ability of the detection of high-frequency acoustic emission signals. The experimental results demonstrate that the DOP of the laser beam can be continuously tuned from 0.2% to 100%, and the power fluctuation in the whole DOP tuning range is less than 0.05 dBm. A high-frequency response up to 300 kHz is reached, and the high sensing sensitivity for detections of weak corona discharges, as well as partial discharges also is verified. PMID:24824371

  15. 2 μm and mid-IR fiber-laser-based sources for OCM

    NASA Astrophysics Data System (ADS)

    Kieleck, C.; Berrou, A.; Kneis, C.; Donelan, B.; Eichhorn, M.

    2014-10-01

    This paper describes new laser sources and non linear conversion setups for 2 μm and mid-IR generation based on fiber technologies developed at ISL. Especially for jamming heat-seeking missiles, these novel designs allow to propose future compact, efficient and integrable laser systems. The specialty of the ISL technology lies in the use of single 2 μm fiber laser oscillators, which deliver the full output peak power to pump optical parametric oscillators or nonlinear fibers. No multi-stage amplifiers at 2 μm or 1.55 μm are necessary to efficiently pump non linear converters to obtained useful energies in the mid-infrared spectral range. This technology leads to efficient, simple and promising setups to be implemented in flying platforms. The best results achieved in continuous-wave (CW), Q-switched (QS) and mode-locked (ML) regimes with fiber lasers based on Tm3+-doped and Tm3+,Ho3+-codoped fibers are presented. Up to 70 W of average power was achieved around 2 μm with a Tm3+-doped fiber in CW regime. In ML regimes, at a repetition rate of 66 MHz, 50 W of average power was reached. In QS regime, up to 32 W of average power was generated around 2 μm with a polarization maintaining Tm3+-doped fiber at a repetition rate of 40 kHz. With a Tm3+,Ho3+-codoped fiber, up to 25 W of average power was obtained around 2070 nm in Q-switched regime. For example at 50 kHz, the pulse duration was around 50 ns at the maximum output power. The M2 was estimated to be less than 1.2. The emission from QS fiber lasers was used to directly pump OP-GaAs and ZGP OPOs. For example, in band II, up to 6.5 W of averaged power was recently obtained from a ZGP OPO pumped by a Tm3+-doped fiber laser. At 40 kHz repetition rate, the pulse duration was around 65 ns at the maximum output power. For 3 W of averaged output power, the M2 of the signal beam was estimated to be less than 2.1 and less than 2.4 for the idler beam. Using a mode-locked Tm3+-doped fiber laser to pump a ZBLAN fiber at an

  16. Widely tunable mid-infrared fiber laser source based on soliton self-frequency shift in microstructured tellurite fiber.

    PubMed

    Koptev, M Yu; Anashkina, E A; Andrianov, A V; Dorofeev, V V; Kosolapov, A F; Muravyev, S V; Kim, A V

    2015-09-01

    A turnkey fiber laser source generating high-quality pulses with a spectral sech shape and Fourier transform-limited duration of order 100 fs widely tunable in the 1.6-2.65 μm range is presented. It is based on Raman soliton self-frequency shifting in the suspended-core microstructured TeO2-WO3-La2O3 glass fiber pumped by a hybrid Er/Tm fiber system. Detailed experimental and theoretical studies, which are in a very good agreement, of nonlinear pulse dynamics in the tellurite fiber with carefully measured and calculated parameters are reported. A quantitatively verified numerical model is used to show Raman soliton shift in the range well beyond 3 μm for increased pump energy.

  17. Graphene based widely-tunable and singly-polarized pulse generation with random fiber lasers

    PubMed Central

    Yao, B. C.; Rao, Y. J.; Wang, Z. N.; Wu, Y.; Zhou, J. H.; Wu, H.; Fan, M. Q.; Cao, X. L.; Zhang, W. L.; Chen, Y. F.; Li, Y. R.; Churkin, D.; Turitsyn, S.; Wong, C. W.

    2015-01-01

    Pulse generation often requires a stabilized cavity and its corresponding mode structure for initial phase-locking. Contrastingly, modeless cavity-free random lasers provide new possibilities for high quantum efficiency lasing that could potentially be widely tunable spectrally and temporally. Pulse generation in random lasers, however, has remained elusive since the discovery of modeless gain lasing. Here we report coherent pulse generation with modeless random lasers based on the unique polarization selectivity and broadband saturable absorption of monolayer graphene. Simultaneous temporal compression of cavity-free pulses are observed with such a polarization modulation, along with a broadly-tunable pulsewidth across two orders of magnitude down to 900 ps, a broadly-tunable repetition rate across three orders of magnitude up to 3 MHz, and a singly-polarized pulse train at 41 dB extinction ratio, about an order of magnitude larger than conventional pulsed fiber lasers. Moreover, our graphene-based pulse formation also demonstrates robust pulse-to-pulse stability and wide-wavelength operation due to the cavity-less feature. Such a graphene-based architecture not only provides a tunable pulsed random laser for fiber-optic sensing, speckle-free imaging, and laser-material processing, but also a new way for the non-random CW fiber lasers to generate widely tunable and singly-polarized pulses. PMID:26687730

  18. Graphene based widely-tunable and singly-polarized pulse generation with random fiber lasers

    NASA Astrophysics Data System (ADS)

    Yao, B. C.; Rao, Y. J.; Wang, Z. N.; Wu, Y.; Zhou, J. H.; Wu, H.; Fan, M. Q.; Cao, X. L.; Zhang, W. L.; Chen, Y. F.; Li, Y. R.; Churkin, D.; Turitsyn, S.; Wong, C. W.

    2015-12-01

    Pulse generation often requires a stabilized cavity and its corresponding mode structure for initial phase-locking. Contrastingly, modeless cavity-free random lasers provide new possibilities for high quantum efficiency lasing that could potentially be widely tunable spectrally and temporally. Pulse generation in random lasers, however, has remained elusive since the discovery of modeless gain lasing. Here we report coherent pulse generation with modeless random lasers based on the unique polarization selectivity and broadband saturable absorption of monolayer graphene. Simultaneous temporal compression of cavity-free pulses are observed with such a polarization modulation, along with a broadly-tunable pulsewidth across two orders of magnitude down to 900 ps, a broadly-tunable repetition rate across three orders of magnitude up to 3 MHz, and a singly-polarized pulse train at 41 dB extinction ratio, about an order of magnitude larger than conventional pulsed fiber lasers. Moreover, our graphene-based pulse formation also demonstrates robust pulse-to-pulse stability and wide-wavelength operation due to the cavity-less feature. Such a graphene-based architecture not only provides a tunable pulsed random laser for fiber-optic sensing, speckle-free imaging, and laser-material processing, but also a new way for the non-random CW fiber lasers to generate widely tunable and singly-polarized pulses.

  19. Three-dimensional graphene based passively mode-locked fiber laser.

    PubMed

    Yang, Y; Loeblein, M; Tsang, S H; Chow, K K; Teo, E H T

    2014-12-15

    We present an all-fiber passively mode-locked fiber laser incorporating three-dimensional (3D) graphene as a saturable absorber (SA) for the first time to the best of our knowledge. The 3D graphene is synthesized by template-directed chemical vapor deposition (CVD). The SA is then simply formed by sandwiching the freestanding 3D graphene between two conventional fiber connectors without any deposition process. It is demonstrated that such 3D graphene based SA is capable to produce high quality mode-locked pulses. A passively mode-locked fiber laser is constructed and stable output pulses with a fundamental repetition rate of ~9.9 MHz and a pulse width of ~1 ps are generated from the fiber laser. The average output power of the laser is ~10.5 mW while the output pulse is operating at single pulse region. The results imply that the freestanding 3D graphene can be applied as an effective saturable absorption material for passively mode-locked lasers. PMID:25607096

  20. Three-dimensional graphene based passively mode-locked fiber laser.

    PubMed

    Yang, Y; Loeblein, M; Tsang, S H; Chow, K K; Teo, E H T

    2014-12-15

    We present an all-fiber passively mode-locked fiber laser incorporating three-dimensional (3D) graphene as a saturable absorber (SA) for the first time to the best of our knowledge. The 3D graphene is synthesized by template-directed chemical vapor deposition (CVD). The SA is then simply formed by sandwiching the freestanding 3D graphene between two conventional fiber connectors without any deposition process. It is demonstrated that such 3D graphene based SA is capable to produce high quality mode-locked pulses. A passively mode-locked fiber laser is constructed and stable output pulses with a fundamental repetition rate of ~9.9 MHz and a pulse width of ~1 ps are generated from the fiber laser. The average output power of the laser is ~10.5 mW while the output pulse is operating at single pulse region. The results imply that the freestanding 3D graphene can be applied as an effective saturable absorption material for passively mode-locked lasers.

  1. 100-watt fiber-based green laser with near diffraction-limited beam quality

    NASA Astrophysics Data System (ADS)

    Hu, Dan; Eisenberg, Eric; Brar, Khush; Yilmaz, Tolga; Honea, Eric

    2010-02-01

    An air-cooled, light-weight, fiber-based, high power green laser has been prototyped. The system consists of an all-fibercoupled IR pump laser at 1064 nm and a frequency-conversion module in a compact and flexible configuration. The IR laser operates in QCW mode, with 10 MHz pulse repetition frequency and 3-5 ns pulse width, to generate sufficient peak power for frequency doubling in the converter module. The IR laser can produce more than 200 W in a linearlypolarized diffraction-limited output beam with high spectral brightness for frequency conversion. The converter module has an input telescope and an oven with a nonlinear crystal to efficiently convert the 1064-nm IR fiber laser output to 532-nm green output. The IR laser and conversion module are connected via a stainless-steel protected delivery fiber for optical beam delivery and an electrical cable harness for electrical power delivery and system control. The beam quality of the 532 nm output remains near diffraction-limited, with M2<1.4. Up to 101 W of 532 nm output was demonstrated and multi-hour runs were characterized at 75 W output. The weights of the IR laser package and doubler are 69 lbs and 14 lbs respectively. An overview of the system and full characterization results will be presented. Such compact, highbrightness green laser sources are expected to enable various scientific, defense and industrial applications.

  2. Wavelength-switchable fiber laser based on temperature-dependent transmittance of a LPFG

    NASA Astrophysics Data System (ADS)

    Anzueto-Sánchez, G.; Castrellon-Uribe, J.; Torres-Gómez, I.; Martínez-Rios, A.; Osuna-Galán, I.

    2011-09-01

    A wavelength-switchable erbium-doped fiber ring laser is demonstrated and reported. The erbium-doped fiber net gain of the fiber laser is modified by controlled heating of a Long Period Fiber Grating (LPFG) inserted into the laser cavity. The rejection band of the LPFG is altered in the resonant wavelength and loss according to the exposed temperature and consequently, the operating wavelength of the fiber laser can be switched from a single wavelength operation at 1563 nm to a simultaneous operation at 1527 and 1563 nm. The laser system can be used as a temperature fiber sensor as well.

  3. Endoluminal non-contact soft tissue ablation using fiber-based Er:YAG laser delivery

    NASA Astrophysics Data System (ADS)

    Kundrat, Dennis; Fuchs, Alexander; Schoob, Andreas; Kahrs, Lüder A.; Ortmaier, Tobias

    2016-03-01

    The introduction of Er:YAG lasers for soft and hard tissue ablation has proven promising results over the last decades due to strong absorption at 2.94 μm wavelength by water molecules. An extension to endoluminal applications demands laser delivery without mirror arms due to dimensional constraints. Therefore, fiber-based solutions are advanced to provide exible access while keeping space requirements to a minimum. Conventional fiber-based treatments aim at laser-tissue interactions in contact mode. However, this procedure is associated with disadvantages such as advancing decrease in power delivery due to particle coverage of the fiber tip, tissue carbonization, and obstructed observation of the ablation progress. The objective of this work is to overcome aforementioned limitations with a customized fiber-based module for non-contact robot-assisted endoluminal surgery and its associated experimental evaluation. Up to the authors knowledge, this approach has not been presented in the context of laser surgery at 2.94 μm wavelength. The preliminary system design is composed of a 3D Er:YAG laser processing unit enabling automatic laser to fiber coupling, a GeO2 solid core fiber, and a customized module combining collimation and focusing unit (focal length of 20 mm, outer diameter of 8 mm). The performance is evaluated with studies on tissue substitutes (agar-agar) as well as porcine samples that are analysed by optical coherence tomography measurements. Cuts (depths up to 3mm) with minimal carbonization have been achieved under adequate moistening and sample movement (1.5mms-1). Furthermore, an early cadaver study is presented. Future work aims at module miniaturization and integration into an endoluminal robot for scanning and focus adaptation.

  4. Highly-sensitive magnetic field sensor based on fiber ring laser.

    PubMed

    Deng, Ming; Liu, Danhui; Huang, Wei; Zhu, Tao

    2016-01-11

    A highly sensitive magnetic field sensor based on a fiber ring laser has been proposed and experimentally demonstrated. The magnetic field sensor was fabricated by introducing a rotary apparatus modulated by an external magnetic field into the fiber cavity to twist one section of the fiber. Due to the remarkable birefringence change induced into the laser cavity, the beat frequency generated between two polarizations of the laser is sensitive to the variation of applied magnetic field intensity. Experimental results show that the polarization mode beat frequency linearly shifts with the increment of the magnetic field intensity and the sensitivity reaches up to 7.09 KHz/Oe in the range of 0 - 437 Oe. Therefore, it will be a promising candidate for the weak magnetic field applications including military, hazard forecast and biomedical fields.

  5. Highly-sensitive magnetic field sensor based on fiber ring laser.

    PubMed

    Deng, Ming; Liu, Danhui; Huang, Wei; Zhu, Tao

    2016-01-11

    A highly sensitive magnetic field sensor based on a fiber ring laser has been proposed and experimentally demonstrated. The magnetic field sensor was fabricated by introducing a rotary apparatus modulated by an external magnetic field into the fiber cavity to twist one section of the fiber. Due to the remarkable birefringence change induced into the laser cavity, the beat frequency generated between two polarizations of the laser is sensitive to the variation of applied magnetic field intensity. Experimental results show that the polarization mode beat frequency linearly shifts with the increment of the magnetic field intensity and the sensitivity reaches up to 7.09 KHz/Oe in the range of 0 - 437 Oe. Therefore, it will be a promising candidate for the weak magnetic field applications including military, hazard forecast and biomedical fields. PMID:26832294

  6. Type IIa Bragg grating based ultra-short DBR fiber laser with high temperature resistance.

    PubMed

    Ran, Yang; Feng, Fu-Rong; Liang, Yi-Zhi; Jin, Long; Guan, Bai-Ou

    2015-12-15

    We report on the fabrication of a thermally resistant ultra-short distributed Bragg reflector (DBR) fiber laser based on the photo inscription of two wavelength-matched type IIa gratings in a thin-core Er-doped fiber. With continuous UV exposure, each Bragg reflector initially grows as a type I grating, followed by decay in strength, and then re-grows as a type IIa grating with enhanced thermal resistance. The DBR laser, with an entire length of 13 mm, can stably operate at 600°C with single longitude mode, which provides potential applications in high temperature environments. PMID:26670491

  7. Widely tunable erbium-doped fiber laser based on multimode interference effect.

    PubMed

    Castillo-Guzman, A; Antonio-Lopez, J E; Selvas-Aguilar, R; May-Arrioja, D A; Estudillo-Ayala, J; LiKamWa, P

    2010-01-18

    A widely tunable erbium-doped all-fiber laser has been demonstrated. The tunable mechanism is based on a novel tunable filter using multimode interference effects (MMI). The tunable MMI filter was applied to fabricate a tunable erbium-doped fiber laser via a standard ring cavity. A tuning range of 60 nm was obtained, ranging from 1549 nm to 1609 nm, with a signal to noise ratio of 40 dB. The tunable MMI filter mechanism is very simple and inexpensive, but also quite efficient as a wavelength tunable filter.

  8. Tunable dual-wavelength fiber laser with ultra-narrow linewidth based on Rayleigh backscattering.

    PubMed

    Zhu, Tao; Zhang, Baomei; Shi, Leilei; Huang, Shihong; Deng, Ming; Liu, Jianguo; Li, Xiong

    2016-01-25

    Dual-wavelength fiber lasers with ultra-narrow linewidth find wide applications in high-speed optical communications, fiber optic sensors, high resolution measurements and medical instruments and microwave or terahertz generation systems. Based on the linewidth compression mechanism due to Rayleigh backscattering, this paper adopts a simple ring structure cooperated with two fiber Bragg gratings centered at 1550 nm and 1530 nm respectively, achieving a dual-wavelength fiber laser with ultra-narrow linewidth, with a 3dB linewidth of ~700 Hz for each wavelength, and the SNR of 60dB. Tuning the center wavelength of one of the two FBGs while the other one keeps unchanged, the fiber laser keeps stable dual-wavelength lasing and the linewidth is still ~700 Hz. It can be seen that the compression for the linewidth based on the Rayleigh backscattering can be used in multi-wavelength laser systems, and because of the characteristic of the Rayleigh backscattering, the method has great potential in the application of wide wavelength range linewidth compression from the ultraviolet to the far infrared. PMID:26832513

  9. Ferrofluid-based optical fiber magnetic field sensor fabricated by femtosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Song, Yang; Yuan, Lei; Hua, Liwei; Zhang, Qi; Lei, Jincheng; Huang, Jie; Xiao, Hai

    2016-02-01

    Optofluid system has been more and more attractive in optical sensing applications such as chemical and biological analysis as it incorporates the unique features from both integrated optics and microfluidics. In recent years, various optofluid based structures have been investigated in/on an optical fiber platform which is referred to as "lab in/on a fiber". Among those integrated structures, femto-second laser micromaching technique plays an important role due to its high precision fabrication, flexible design, 3D capability, and compatible with other methods. Here we present a ferrofluid based optical fiber magnetic field sensor fabricated by femtosecond (fs) laser irradiation .With the help of fs laser micromaching technique, a micro-reservoir made by capillary tube assembled in a single mode optical fiber could be fabricated. The micro-reservoir functions as a fiber inline Fabry-Perot (FP) cavity which is filled by ferrofluid liquid. The refractive index of the ferrofluid varies as the surrounding magnetic field strength changes, which can be optically probed by the FP interferometer. A fringe visibility of up to 30 dB can be achieved with a detection limit of around 0.4 Gausses. Due to the fabrication, micro-reservoirs can be assembled with optical fiber and distinguished through a microwave-photonic interrogation system. A quasi-distributed magnetic field sensing application has been demonstrated with a high spatial resolution of around 10 cm.

  10. Realization of fiber-based laser Doppler vibrometer with serrodyne frequency shifting.

    PubMed

    Li, Yanlu; Meersman, Stijn; Baets, Roel

    2011-06-10

    We demonstrate a laser Doppler vibrometer (LDV) based on the serrodyne frequency shifting technique. A proof-of-principle system is implemented on the basis of fiber-optic components but opens the way toward an ultracompact integrated LDV system on a silicon chip. With a low laser power of 50  μW, the serrodyne LDV was able to measure submicrometer vibrations with frequencies in the audio range.

  11. Truly random bit generation based on a novel random Brillouin fiber laser.

    PubMed

    Xiang, Dao; Lu, Ping; Xu, Yanping; Gao, Song; Chen, Liang; Bao, Xiaoyi

    2015-11-15

    We propose a novel dual-emission random Brillouin fiber laser (RBFL) with bidirectional pumping operation. Numerical simulations and experimental verification of the chaotic temporal and statistical properties of the RBFL are conducted, revealing intrinsic unpredictable intensity fluctuations and two completely uncorrelated laser outputs. A random bit generator based on quantum noise sources in the random Fabry-Perot resonator of the RBFL is realized at a bit rate of 5 Mbps with verified randomness.

  12. Truly random bit generation based on a novel random Brillouin fiber laser.

    PubMed

    Xiang, Dao; Lu, Ping; Xu, Yanping; Gao, Song; Chen, Liang; Bao, Xiaoyi

    2015-11-15

    We propose a novel dual-emission random Brillouin fiber laser (RBFL) with bidirectional pumping operation. Numerical simulations and experimental verification of the chaotic temporal and statistical properties of the RBFL are conducted, revealing intrinsic unpredictable intensity fluctuations and two completely uncorrelated laser outputs. A random bit generator based on quantum noise sources in the random Fabry-Perot resonator of the RBFL is realized at a bit rate of 5 Mbps with verified randomness. PMID:26565888

  13. Widely tunable 11 GHz femtosecond fiber laser based on a nonmode-locked source.

    PubMed

    Prantil, Matthew A; Cormier, Eric; Dawson, Jay W; Gibson, David J; Messerly, Michael J; Barty, C P J

    2013-09-01

    An 11 GHz fiber laser built on a modulated cw platform is described and characterized. This compact, vibration-insensitive, fiber-based system can be operated at wavelengths compatible with high-energy fiber technology, is driven by an RF signal directly, and is tunable over a wide range of drive frequencies. The demonstration system when operated at 1040 nm is capable of 50 ns bursts of 575 micropulses produced at a macropulse rate of 83 kHz where the macropulse and micropulse energies are 1.8 and 3.2 nJ, respectively. Micropulse durations of 850 fs are demonstrated. Extensions to shorter duration are discussed.

  14. Widely tunable 11 GHz femtosecond fiber laser based on a nonmode-locked source.

    PubMed

    Prantil, Matthew A; Cormier, Eric; Dawson, Jay W; Gibson, David J; Messerly, Michael J; Barty, C P J

    2013-09-01

    An 11 GHz fiber laser built on a modulated cw platform is described and characterized. This compact, vibration-insensitive, fiber-based system can be operated at wavelengths compatible with high-energy fiber technology, is driven by an RF signal directly, and is tunable over a wide range of drive frequencies. The demonstration system when operated at 1040 nm is capable of 50 ns bursts of 575 micropulses produced at a macropulse rate of 83 kHz where the macropulse and micropulse energies are 1.8 and 3.2 nJ, respectively. Micropulse durations of 850 fs are demonstrated. Extensions to shorter duration are discussed. PMID:23988917

  15. Continuous glucose determination using fiber-based tunable mid-infrared laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Yu, Songlin; Li, Dachao; Chong, Hao; Sun, Changyue; Xu, Kexin

    2014-04-01

    Wavelength-tunable laser spectroscopy in combination with a small-sized fiber-optic attenuated total reflection (ATR) sensor (fiber-based evanescent field analysis, FEFA) is reported for the continuous measurement of the glucose level. We propose a method of controlling and stabilizing the wavelength and power of laser emission and present a newly developed mid-infrared wavelength-tunable laser with a broad emission spectrum band of 9.19-9.77 μm (1024-1088 cm-1). The novel small-sized flow-through fiber-optic ATR sensor with long optical sensing length was used for glucose level determination. The experimental results indicate that the noise-equivalent concentration of this laser measurement system is as low as 3.8 mg/dL, which is among the most precise glucose measurements using mid-infrared spectroscopy. The sensitivity, which is three times that of conventional Fourier transform infrared spectrometer, was acquired because of the higher laser power and higher spectral resolution. The best prediction of the glucose concentration in phosphate buffered saline solution was achieved using the five-variable partial least-squares model, yielding a root-mean-square error of prediction as small as 3.5 mg/dL. The high sensitivity, multiple tunable wavelengths and small fiber-based sensor with long optical sensing length make glucose determination possible in blood or interstitial fluid in vivo.

  16. NLSE-based model of a random distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Smirnov, Sergey V.; Churkin, Dmitry V.

    2014-05-01

    In this work we propose a NLSE-based model of power and spectral properties of the random distributed feedback (DFB) fiber laser. The model is based on coupled set of non-linear Schrödinger equations for pump and Stokes waves with the distributed feedback due to Rayleigh scattering. The model considers random backscattering via its average strength, i.e. we assume that the feedback is incoherent. In addition, this allows us to speed up simulations sufficiently (up to several orders of magnitude). We found that the model of the incoherent feedback predicts the smooth and narrow (comparing with the gain spectral profile) generation spectrum in the random DFB fiber laser. The model allows one to optimize the random laser generation spectrum width varying the dispersion and nonlinearity values: we found, that the high dispersion and low nonlinearity results in narrower spectrum that could be interpreted as four-wave mixing between different spectral components in the quasi-mode-less spectrum of the random laser under study could play an important role in the spectrum formation. Note that the physical mechanism of the random DFB fiber laser formation and broadening is not identified yet. We investigate temporal and statistical properties of the random DFB fiber laser dynamics. Interestingly, we found that the intensity statistics is not Gaussian. The intensity auto-correlation function also reveals that correlations do exist. The possibility to optimize the system parameters to enhance the observed intrinsic spectral correlations to further potentially achieved pulsed (mode-locked) operation of the mode-less random distributed feedback fiber laser is discussed.

  17. Experimental investigation of thermal effects and PCT on FBGs-based linearly polarized fiber laser performance.

    PubMed

    Huang, Long; Ma, Pengfei; Tao, Rumao; Shi, Chen; Wang, Xiaolin; Zhou, Pu

    2015-04-20

    We experimentally study the impacts of thermal effects and polarization crosstalk (PCT) on the performance of FBGs-based linearly polarized all-fiber laser. The mechanism that the thermal effects and PCT influence the performance of the laser is analyzed. Thermally-dependent reflection peaks of polarization maintaining (PM) fiber Bragg gratings are revealed to be the prime reason why temperature influences spectrum, output power, and polarization property of the laser. The PCT would also influence the performance of the laser seriously in the case of mismatched angle even with effectively overlapped spectrum. It is revealed experimentally that stable linearly polarized output can be obtained if a certain pair of aligned principal axes of PM FBGs is not only spectrally overlapped but also strictly angle matched. Further, we point out that accurate temperature control and careful angle match are essential for stable linearly polarized output and even possible power scaling further. PMID:25969091

  18. Fiber-Type Random Laser Based on a Cylindrical Waveguide with a Disordered Cladding Layer

    PubMed Central

    Zhang, Wei Li; Zheng, Meng Ya; Ma, Rui; Gong, Chao Yang; Yang, Zhao Ji; Peng, Gang Ding; Rao, Yun Jiang

    2016-01-01

    This letter reports a fiber-type random laser (RL) which is made from a capillary coated with a disordered layer at its internal surface and filled with a gain (laser dye) solution in the core region. This fiber-type optical structure, with the disordered layer providing randomly scattered light into the gain region and the cylindrical waveguide providing confinement of light, assists the formation of random lasing modes and enables a flexible and efficient way of making random lasers. We found that the RL is sensitive to laser dye concentration in the core region and there exists a fine exponential relationship between the lasing intensity and particle concentration in the gain solution. The proposed structure could be a fine platform of realizing random lasing and random lasing based sensing. PMID:27220636

  19. Liquid level sensor based on fiber ring laser with single-mode-offset coreless-single-mode fiber structure

    NASA Astrophysics Data System (ADS)

    Wang, Zixiao; Tan, Zhongwei; Xing, Rui; Liang, Linjun; Qi, Yanhui; Jian, Shuisheng

    2016-10-01

    A novel reflective liquid level sensor based on single-mode-offset coreless-single-mode (SOCS) fiber structure is proposed and experimentally demonstrated. Theory analyses and experimental results indicate that offset fusion can remarkably enhance the sensitivity of sensor. Ending-reflecting structure makes the sensor compact and easy to deploy. Meanwhile, we propose a laser sensing system, and the SOCS structure is used as sensing head and laser filter simultaneously. Experimental results show that laser spectra with high optical signal-to-noise ratio (-30 dB) and narrow 3-dB bandwidth (<0.15 nm) are achieved. Various liquids with different indices are used for liquid level sensing, besides, the refractive index sensitivity is also investigated. In measurement range, the sensing system presents steady laser output.

  20. Genetic algorithm based optimization of pulse profile for MOPA based high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawei; Tang, Ming; Shi, Jun; Fu, Songnian; Li, Lihua; Liu, Ying; Cheng, Xueping; Liu, Jian; Shum, Ping

    2015-03-01

    Although the Master Oscillator Power-Amplifier (MOPA) based fiber laser has received much attention for laser marking process due to its large tunabilty of pulse duration (from 10ns to 1ms), repetition rate (100Hz to 500kHz), high peak power and extraordinary heat dissipating capability, the output pulse deformation due to the saturation effect of fiber amplifier is detrimental for many applications. We proposed and demonstrated that, by utilizing Genetic algorithm (GA) based optimization technique, the input pulse profile from the master oscillator (current-driven laser diode) could be conveniently optimized to achieve targeted output pulse shape according to real parameters' constraints. In this work, an Yb-doped high power fiber amplifier is considered and a 200ns square shaped pulse profile is the optimization target. Since the input pulse with longer leading edge and shorter trailing edge can compensate the saturation effect, linear, quadratic and cubic polynomial functions are used to describe the input pulse with limited number of unknowns(<5). Coefficients of the polynomial functions are the optimization objects. With reasonable cost and hardware limitations, the cubic input pulse with 4 coefficients is found to be the best as the output amplified pulse can achieve excellent flatness within the square shape. Considering the bandwidth constraint of practical electronics, we examined high-frequency component cut-off effect of input pulses and found that the optimized cubic input pulses with 300MHz bandwidth is still quite acceptable to satisfy the requirement for the amplified output pulse and it is feasible to establish such a pulse generator in real applications.

  1. Passive compensation of the thermal drift of magnetostriction based Q-switched fiber lasers

    NASA Astrophysics Data System (ADS)

    Pérez-Millán, P.; Díez, A.; Cruz, J. L.; Andrés, M. V.

    2009-02-01

    The authors propose and demonstrate a method to compensate the thermal drift of magnetostriction based Q-switched fiber lasers, which is caused by the eddy currents induced in the Terfenol-D magnetostrictive actuators. The consequent wavelength detuning between the fiber gratings of the laser is passively compensated by the use of Monel 400 as thermal actuator of the non-modulated grating. A highly stable pulsed signal is achieved in the range of 1 Hz-5 kHz, with a wavelength detuning between gratings maintained below 10 pm. Furthermore, an optimization of the use of the pump power is proposed, utilizing part of it for simultaneously pumping a fiber optic based amplification stage.

  2. All-fiber mode-locked laser based on microfiber polarizer.

    PubMed

    Zhang, Zhishen; Gan, Jiulin; Yang, Tong; Wu, Yuqing; Li, Qingyu; Xu, Shanhui; Yang, Zhongmin

    2015-03-01

    A novel all-fiber mode-locked fiber laser based on microfiber polarizer is proposed and demonstrated. The microfiber polarizer is composed of two pieces of microfibers that are finely manipulated to be partly overlapped. Because of the asymmetric cross section, the microfiber polarizer shows a strong birefringence that ultimately induces a high polarization-selective feature. Compared with other polarizers, the microfiber polarizer owns the merits of simpler fabrication, lower cost, broader band, and more compact size. The polarization extinction ratio of the microfiber polarizer is 26 dB, and the stable pulse sequence with the duration of 2.9 ps is generated from this microfiber polarizer based all-fiber mode-locked laser.

  3. 2-μm fiber laser sources for sensing

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Geng, Jihong; Jiang, Shibin

    2014-06-01

    2-μm fiber lasers have become a research topic with an increased emphasis due to a variety of applications including eye-safe LIDAR, spectroscopy, remote sensing, and mid-infrared (mid-IR) frequency generation. We review our latest development on various 2-μm fiber laser sources, including single-frequency fiber lasers, Q-switched fiber lasers, mode-locked fiber lasers, and mid-IR supercontinuum fiber sources. All these fiber laser sources are based on thulium and holmium ions using our proprietary glass fiber technology. Potential applications of these fiber laser sources for sensing are also briefly discussed.

  4. Prospects for diode-pumped alkali-atom-based hollow-core photonic-crystal fiber lasers.

    PubMed

    Sintov, Yoav; Malka, Dror; Zalevsky, Zeev

    2014-08-15

    By employing large hollow-core Kagome fiber in a double-clad configuration, the performance of a potentially rubidium vapor-based fiber laser is explored. The absorbed power and laser efficiency versus pump power are calculated utilizing a simple laser model. Our results show that a Kagome-based high-power fiber laser is feasible provided that the value of the collisional fine-structure mixing rate will be elevated by increasing the ambient temperature or by increasing the helium pressure.

  5. Noninvasive respiration movement sensor based on distributed Bragg reflector fiber laser with beat frequency interrogation.

    PubMed

    Wo, Jianghai; Wang, He; Sun, Qizhen; Shum, Perry Ping; Liu, Deming

    2014-01-01

    A distributed Bragg reflector fiber laser-based respiration movement monitoring system has been proposed and experimentally demonstrated. To fabricate the sensing element for respiration monitoring, a fixture that consists of a plastic plate, a section of elastic textile is employed to experience and transfer the belly expansion induced pressure onto the cross-section of the laser cavity. By tracing the change of the beat signal that generates between two polarization lasing modes, the information of the respiration movement can be extracted in real time. Experimental studies have demonstrated that the system is able to detect both respiration waveform and rate simultaneously. Moreover, the recorded results show that the different gestures as well as the physiology conditions can be distinguished by monitoring the amplitude and period change of the waveform. It is anticipated that the proposed fiber laser-based sensor would be highly suitable for respiratory monitoring.

  6. Multiphoton microscopy system with a compact fiber-based femtosecond-pulse laser and handheld probe.

    PubMed

    Liu, Gangjun; Kieu, Khanh; Wise, Frank W; Chen, Zhongping

    2011-01-01

    We report on the development of a compact multiphoton microscopy (MPM) system that integrates a compact and robust fiber laser with a miniature probe. The all normal dispersion fiber femtosecond laser has a central wavelength of 1.06 μm, pulse width of 125 fs and average power of more than 1 W. A double cladding photonic crystal fiber was used to deliver the excitation beam and to collect the two-photon signal. The hand-held probe included galvanometer-based mirror scanners, relay lenses and a focusing lens. The packaged probe had a diameter of 16 mm. Second harmonic generation (SHG) images and two-photon excited fluorescence (TPEF) images of biological tissues were demonstrated using the system. PMID:20635426

  7. A cantilever based optical fiber acoustic sensor fabricated by femtosecond laser micromachining

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Yuan, Lei; Huang, Jie; Xiao, Hai

    2016-04-01

    In this paper, we present a pure silica micro-cantilever based optical fiber sensor for acoustic wave detection. The cantilever is directly fabricated by fs laser micromachining on an optical fiber tip functioning as an inline Fabry-Perot interferometer (FPI). The applied acoustic wave pressurizes the micro-cantilever beam and the corresponding dynamic signals can be probed by the FPI. The thickness, length, and width of the micro-cantilever beam can be flexibly designed and fabricated so that the sensitivity, frequency response, and the total measurement range can be varied to fit many practical applications. Experimental results will be presented and analyzed. Due to the assembly free fabrication of the fs-laser, multiple micro-cantilever beams could be potentially fabricated in/on a single optical fiber for quasi-distributed acoustic mapping with high spatial resolution.

  8. A microwave photonic filter based on multi-wavelength fiber laser and infinite impulse response

    NASA Astrophysics Data System (ADS)

    Xu, Dong; Cao, Ye; Zhao, Ai-hong; Tong, Zheng-rong

    2016-09-01

    A microwave photonic filter (MPF) based on multi-wavelength fiber laser and infinite impulse response (IIR) is proposed. The filter uses a multi-wavelength fiber laser as the light source, two sections of polarization maintaining fiber (PMF) and three polarization controllers (PCs) as the laser frequency selection device. By adjusting the PC to change the effective length of the PMF, the laser can obtain three wavelength spacings, which are 0.44 nm, 0.78 nm and 1.08 nm, respectively. And the corresponding free spectral ranges ( FSRs) are 8.46 GHz, 4.66 GHz and 3.44 GHz, respectively. Thus changing the wavelength spacing of the laser can make the FSR variable. An IIR filter is introduced based on a finite impulse response (FIR) filter. Then the 3-dB bandwidth of the MPF is reduced, and the main side-lobe suppression ratio ( MSSR) is increased. By adjusting the gain of the radio frequency (RF) signal amplifier, the frequency response of the filter can be enhanced.

  9. Polarization domain wall pulses in a microfiber-based topological insulator fiber laser.

    PubMed

    Liu, Jingmin; Li, Xingliang; Zhang, Shumin; Zhang, Han; Yan, Peiguang; Han, Mengmeng; Pang, Zhaoguang; Yang, Zhenjun

    2016-01-01

    Topological insulators (TIs), are novel two-dimension materials, which can act as effective saturable absorbers (SAs) in a fiber laser. Moreover, based on the evanescent wave interaction, deposition of the TI on microfiber would create an effective SA, which has combined advantages from the strong nonlinear optical response in TI material together with the sufficiently-long-range interaction length in fiber taper. By using this type of TI SA, various scalar solitons have been obtained in fiber lasers. However, a single mode fiber always exhibits birefringence, and hence can support two orthogonal degenerate modes. Here we investigate experimentally the vector characters of a TI SA fiber laser. Using the saturated absorption and the high nonlinearity of the TI SA, a rich variety of dynamic states, including polarization-locked dark pulses and their harmonic mode locked counterparts, polarization-locked noise-like pulses and their harmonic mode locked counterparts, incoherently coupled polarization domain wall pulses, including bright square pulses, bright-dark pulse pairs, dark pulses and bright square pulse-dark pulse pairs are all observed with different pump powers and polarization states. PMID:27381942

  10. Polarization domain wall pulses in a microfiber-based topological insulator fiber laser

    PubMed Central

    Liu, Jingmin; Li, Xingliang; Zhang, Shumin; Zhang, Han; Yan, Peiguang; Han, Mengmeng; Pang, Zhaoguang; Yang, Zhenjun

    2016-01-01

    Topological insulators (TIs), are novel two-dimension materials, which can act as effective saturable absorbers (SAs) in a fiber laser. Moreover, based on the evanescent wave interaction, deposition of the TI on microfiber would create an effective SA, which has combined advantages from the strong nonlinear optical response in TI material together with the sufficiently-long-range interaction length in fiber taper. By using this type of TI SA, various scalar solitons have been obtained in fiber lasers. However, a single mode fiber always exhibits birefringence, and hence can support two orthogonal degenerate modes. Here we investigate experimentally the vector characters of a TI SA fiber laser. Using the saturated absorption and the high nonlinearity of the TI SA, a rich variety of dynamic states, including polarization-locked dark pulses and their harmonic mode locked counterparts, polarization-locked noise-like pulses and their harmonic mode locked counterparts, incoherently coupled polarization domain wall pulses, including bright square pulses, bright-dark pulse pairs, dark pulses and bright square pulse-dark pulse pairs are all observed with different pump powers and polarization states. PMID:27381942

  11. Polarization domain wall pulses in a microfiber-based topological insulator fiber laser

    NASA Astrophysics Data System (ADS)

    Liu, Jingmin; Li, Xingliang; Zhang, Shumin; Zhang, Han; Yan, Peiguang; Han, Mengmeng; Pang, Zhaoguang; Yang, Zhenjun

    2016-07-01

    Topological insulators (TIs), are novel two-dimension materials, which can act as effective saturable absorbers (SAs) in a fiber laser. Moreover, based on the evanescent wave interaction, deposition of the TI on microfiber would create an effective SA, which has combined advantages from the strong nonlinear optical response in TI material together with the sufficiently-long-range interaction length in fiber taper. By using this type of TI SA, various scalar solitons have been obtained in fiber lasers. However, a single mode fiber always exhibits birefringence, and hence can support two orthogonal degenerate modes. Here we investigate experimentally the vector characters of a TI SA fiber laser. Using the saturated absorption and the high nonlinearity of the TI SA, a rich variety of dynamic states, including polarization-locked dark pulses and their harmonic mode locked counterparts, polarization-locked noise-like pulses and their harmonic mode locked counterparts, incoherently coupled polarization domain wall pulses, including bright square pulses, bright-dark pulse pairs, dark pulses and bright square pulse-dark pulse pairs are all observed with different pump powers and polarization states.

  12. Demodulation of a fiber Bragg grating sensor system based on a linear cavity multi-wavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Cong, Shan; Sun, Yunxu; Pan, Lifeng; Fang, Yating; Tian, Jiajun; Yang, Yanfu; Yong, Yao

    2011-12-01

    A fiber Bragg grating (FBG) sensor demodulation scheme based on a multi-wavelength erbium-doped fiber laser (EDFL) with linear cavity configuration is presented and demonstrated. The scheme is one linear fiber laser cavity with two FBG sensors as its filters. One is for strain sensing, and the other one is for temperature compensation. A power-symmetric nonlinear optical loop mirror (NOLM) is utilized in the laser in order to suppress the mode competition and hole-burning effect to lase two wavelengths output that correspond with two FBG sensors. The sensing quantity, which is demodulated by spectrometer, is represented by the output wavelength shift of the EDFL with temperature and strain applying on FBG sensors. In the experiment, strain measurement with a minimize resolution of 0.746μɛ, i.e. 0.9pm and adjustable linear sensitivity are achieved. Due to utilizing the linear cavity multi-wavelength EDFL with a NOLM as the light source, the scheme also exhibits important advantages including obviously high signal and noise ratio (SNR) of 40.467dB and low power consuming comparing with common FBG sensors with broadband light as the light source.

  13. Mode-locked ytterbium-doped fiber laser based on topological insulator: Bi₂Se₃.

    PubMed

    Dou, Zhiyuan; Song, Yanrong; Tian, Jinrong; Liu, Jinghui; Yu, Zhenhua; Fang, Xiaohui

    2014-10-01

    We demonstrated an all-normal-dispersion Yb-doped mode-locked fiber laser based on Bi₂Se₃ topological insulator (TI). Different from previous TI-mode-locked fiber lasers in which TIs were mixed with film-forming agent, we used a special way to paste a well-proportioned pure TI on a fiber end-facet. In this way, the effect of the film-forming agent could be removed, thus the heat deposition was relieved and damage threshold could be improved. The modulation depth of the Bi₂Se₃ film was measured to be 5.2%. When we used the Bi₂Se₃ film in the Yb-doped fiber laser, the mode locked pulses with pulse energy of 0.756 nJ, pulse width of 46 ps and the repetition rate of 44.6 MHz were obtained. The maximum average output power was 33.7 mW. When the pump power exceeded 270 mW, the laser can operate in multiple pulse state that six-pulse regime can be realized. This contribution indicates that Bi₂Se₃ has an attractive optoelectronic property at 1μm waveband.

  14. Q-switched fiber laser based on an acousto-optic modulator with injection seeding technique.

    PubMed

    Li, Wencai; Liu, Haowei; Zhang, Ji; Long, Hu; Feng, Sujuan; Mao, Qinghe

    2016-06-10

    The operation mechanism and the pulse property of an actively Q-switched erbium-doped fiber laser based on an acousto-optic modulator (AOM) switch with the injection seeding technique are investigated. Our results show that the Q-switched pulses can be locked to oscillate near a fixed frequency higher than that of the seed laser, though the frequency-shift effect of the AOM impedes stable cavity mode oscillations. The operation mechanism of such Q-switch fiber lasers can be explained by the mutual locking-in among the shifted frequency components originated from the injected coherence seed with the help of the gain dynamics of the Q-switch cavity. Moreover, narrow-linewidth Q-switched pulses with different repetition rates can be obtained with different cavity lengths for incredibly stable output pulses without any use of cavity-stabilized techniques. PMID:27409015

  15. Switchable and multi-wavelength linear fiber laser based on Fabry-Perot and Mach-Zehnder interferometers

    NASA Astrophysics Data System (ADS)

    Gutierrez-Gutierrez, J.; Rojas-Laguna, R.; Estudillo-Ayala, J. M.; Sierra-Hernández, J. M.; Jauregui-Vazquez, D.; Vargas-Treviño, M.; Tepech-Carrillo, L.; Grajales-Coutiño, R.

    2016-09-01

    In this manuscript, switchable and multi-wavelength erbium-doped fiber laser arrangement, based on Fabry-Perot (FPI) and Mach-Zehnder (MZI) interferometers is presented. Here, the FPI is composed by two air-microcavities set into the tip of conventional single mode fiber, this one is used as a partially reflecting mirror and lasing modes generator. And the MZI fabricated by splicing a segment of photonic crystal fiber (PCF) between a single-mode fiber section, was set into an optical fiber loop mirror that acts as full-reflecting and wavelength selective filter. Both interferometers, promotes a cavity oscillation into the fiber laser configuration, besides by curvature applied over the MZI, the fiber laser generates: single, double, triple and quadruple laser emissions with a signal to noise ratio (SNR) of 30 dB. These laser emissions can be switching between them from 1525 nm to 1534 nm by adjusting the curvature radius over the MZI. This laser fiber offers a wavelength and power stability at room temperature, compactness and low implementation cost. Moreover the linear laser proposed can be used in several fields such as spectroscopy, telecommunications and fiber optic sensing systems.

  16. Bragg grating-based fiber laser vibration sensing system with novel phase detection

    NASA Astrophysics Data System (ADS)

    Yang, Xiufeng; Chen, Zhihao; Teo, Ju Teng; Ng, Soon Huat

    2014-01-01

    We characterized the dynamic response of a Bragg grating-based fiber laser sensing system. The sensing system comprises of a narrow line width fiber laser based on π-phase-shifted fiber Bragg grating formed in an active fiber, an unbalanced fiber Michelson interferometer (FMI), which performs wavelength-to-phase mapping, and a phase detection algorithm, which acquires the phase change from the interferometric output signal. The novel phase detection algorithm is developed based on the combination of the two traditional phase generated carrier algorithms: differential-cross-multiplying and arctangent algorithms, and possesses the advantages of the two algorithms. The modulation depth fluctuation of the carrier does not affect the performance of the sensing system. A relatively high side mode suppression ratio of above 50 dB has been achieved within a wide range of carrier amplitude from 1.6 to 5.0 V which correspond to the modulation depth from 1.314 to 4.106 rad. The linearity is 99.082% for the relationship between the power spectral density (dBm/Hz) of the detected signal and the amplitude (mv) of the test signal. The unbalanced FMI is used to eliminate the polarization effect.

  17. Thulium-doped mode-locked all-fiber laser based on NALM and carbon nanotube saturable absorber.

    PubMed

    Chernysheva, M A; Krylov, A A; Kryukov, P G; Arutyunyan, N R; Pozharov, A S; Obraztsova, E D; Dianov, E M

    2012-12-10

    We present a thulium-doped fiber laser mode-locked by a carboxymetylcellulose high-optical quality film with dispersed single-walled carbon nanotubes. Laser system based on the nonlinear amplifying loop mirror generates the shortest pulses earlier obtained in SWCNT mode-locked thulium-doped fiber lasers with a duration of 450 fs and 18 mW maximum average power at 1870 nm.

  18. Upstream capacity upgrade in TDM-PON using RSOA based tunable fiber ring laser.

    PubMed

    Yi, Lilin; Li, Zhengxuan; Dong, Yi; Xiao, Shilin; Chen, Jian; Hu, Weisheng

    2012-04-23

    An upstream multi-wavelength shared (UMWS) time division multiplexing passive optical network (TDM-PON) is presented by using a reflective semiconductor amplifier (RSOA) and tunable optical filter (TOF) based directly modulated fiber ring laser as upstream laser source. The stable laser operation is easily achieved no matter what the bandwidth and shape of the TOF is and it can be directly modulated when the RSOA is driven at its saturation region. In this UMWS TDM-PON system, an individual wavelength can be assigned to the user who has a high bandwidth demand by tuning the central wavelength of the TOF in its upgraded optical network unit (ONU), while others maintain their traditional ONU structure and share the bandwidth via time slots, which greatly and dynamically upgrades the upstream capacity. We experimentally demonstrated the bidirectional transmission of downstream data at 10-Gb/s and upstream data at 1.25-Gb/s per wavelength over 25-km single mode fiber (SMF) with almost no power penalty at both ends. A stable performance is observed for the upstream wavelength tuned from 1530 nm to 1595 nm. Moreover, due to the high extinction ratio (ER) of the upstream signal, the burst-mode transmitting is successfully presented and a better time-division multiplexing performance can be obtained by turning off the unused lasers thanks to the rapid formation of the laser in the fiber ring.

  19. Fiber-Based, Spatially and Temporally Shaped Picosecond UV Laser for Advanced RF Gun Applications

    SciTech Connect

    Shverdin, M Y; Anderson, S G; Betts, S M; Gibson, D J; Hartemann, F V; Hernandez, J E; Johnson, M; Jovanovic, I; Messerly, M; Pruet, J; Tremaine, A M; McNabb, D P; Siders, C W; Barty, C J

    2007-06-08

    The fiber-based, spatially and temporally shaped, picosecond UV laser system described here has been specifically designed for advanced rf gun applications, with a special emphasis on the production of high-brightness electron beams for free-electron lasers and Compton scattering light sources. The laser pulse can be shaped to a flat-top in both space and time with a duration of 10 ps at full width of half-maximum (FWHM) and rise and fall times under 1 ps. The expected pulse energy is 50 {micro}J at 261.75 nm and the spot size diameter of the beam at the photocathode is 2 mm. A fiber oscillator and amplifier system generates a chirped pump pulse at 1047 nm; stretching is achieved in a chirped fiber Bragg grating. A single multi-layer dielectric grating based compressor recompresses the input pulse to 250 fs FWHM and a two stage harmonic converter frequency quadruples the beam. Temporal shaping is achieved with a Michelson-based ultrafast pulse stacking device with nearly 100% throughput. Spatial shaping is achieved by truncating the beam at the 20% energy level with an iris and relay-imaging the resulting beam profile onto the photocathode. The integration of the system, as well as preliminary laser measurements will be presented.

  20. Power scaling analysis of fiber lasers and amplifiers based on non-silica materials

    SciTech Connect

    Dawson, J W; Messerly, M J; Heebner, J E; Pax, P H; Sridharan, A K; Bullington, A L; Beach, R J; Siders, C W; Barty, C P; Dubinskii, M

    2010-03-30

    A developed formalism for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.

  1. Bonding surgical incisions using a temperature-controlled laser system based on a single infrared fiber.

    PubMed

    Gabay, Ilan; Barequet, Irina; Varssano, David; Rosner, Mordechai; Katzir, Abraham

    2013-11-01

    ABSTRACT. Although there has been great interest in laser heating for bonding of surgical incisions in tissues, it has not gained wide acceptance by surgeons. We argue that the main obstacle has been the lack of temperature control, which may lead to a weak bonding. We previously developed a laser bonding system based on two infrared transmitting AgBrCl fibers, one for laser heating and one for temperature control. In view of the inherent limitations of such systems observed in many animal experiments, we developed an improved system based on a single infrared fiber. Besides the decreased dimensions, this system offers many advantages over the two-fiber system. It is less sensitive to accuracy of height and tilt of the fiber distal tip above the tissue, ensuring more accurate heating that can potentially lead to stronger bonding with minimal thermal damage. The system is successfully tested in the soldering of 15 corneal incisions, ex vivo. Histopathology shows little thermal damage and good wound apposition. The average burst pressure is 100±30  mm Hg. These findings indicate the usefulness of the system for ophthalmic surgery as well as other surgical procedures, including endoscopic and robotic surgery.

  2. A multi-point laser Doppler vibrometer with fiber-based configuration

    SciTech Connect

    Yang, C.; Guo, M.; Liu, H.; Yan, K.; Xu, Y. J.; Fu, Y.; Miao, H.

    2013-12-15

    Laser Doppler vibrometer (LDV) is a non-contact optical interferometric system to measure vibrations of structures and machines with a high precision. Normal LDV can only offer a single-point measurement. Scanning LDV is usually impractical to do measurement on transient events. In this paper, a fiber-based self-synchronized multi-point LDV is proposed. The multiple laser beams with different frequency shifts are generated from one laser source. The beams are projected onto a vibrating object, reflected and interfered with a common reference beam. The signal including vibration information of multiple spatial points is captured by one single-pixel photodetector. The optical system is mainly integrated by fiber components for flexibility in measurement. Two experiments are conducted to measure a steady-state simple harmonic vibration of a cantilever beam and a transient vibration of a beam clamped at both ends. In the first measurement, a numerical interpolation is applied to reconstruct the mode shape with increased number of data points. The vibration mode obtained is compared with that from FEM simulation. In transient vibration measurement, the first five resonant frequencies are obtained. The results show the new-reported fiber-based multipoint LDV can offer a vibration measurement on various spatial points simultaneously. With the flexibility of fiber configuration, it becomes more practical for dynamic structural evaluation in industrial areas.

  3. A multi-point laser Doppler vibrometer with fiber-based configuration.

    PubMed

    Yang, C; Guo, M; Liu, H; Yan, K; Xu, Y J; Miao, H; Fu, Y

    2013-12-01

    Laser Doppler vibrometer (LDV) is a non-contact optical interferometric system to measure vibrations of structures and machines with a high precision. Normal LDV can only offer a single-point measurement. Scanning LDV is usually impractical to do measurement on transient events. In this paper, a fiber-based self-synchronized multi-point LDV is proposed. The multiple laser beams with different frequency shifts are generated from one laser source. The beams are projected onto a vibrating object, reflected and interfered with a common reference beam. The signal including vibration information of multiple spatial points is captured by one single-pixel photodetector. The optical system is mainly integrated by fiber components for flexibility in measurement. Two experiments are conducted to measure a steady-state simple harmonic vibration of a cantilever beam and a transient vibration of a beam clamped at both ends. In the first measurement, a numerical interpolation is applied to reconstruct the mode shape with increased number of data points. The vibration mode obtained is compared with that from FEM simulation. In transient vibration measurement, the first five resonant frequencies are obtained. The results show the new-reported fiber-based multipoint LDV can offer a vibration measurement on various spatial points simultaneously. With the flexibility of fiber configuration, it becomes more practical for dynamic structural evaluation in industrial areas.

  4. Power scaling analysis of fiber lasers and amplifiers based on non-silica materials

    NASA Astrophysics Data System (ADS)

    Dawson, Jay W.; Messerly, Michael J.; Heebner, John E.; Pax, Paul H.; Sridharan, Arun K.; Bullington, Amber L.; Beach, Raymond J.; Siders, Craig W.; Barty, C. P. J.; Dubinskii, Mark

    2010-04-01

    A developed formalism1 for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.

  5. Microfiber-based gold nanorods as saturable absorber for femtosecond pulse generation in a fiber laser

    SciTech Connect

    Wang, Xu-De; Luo, Zhi-Chao; Liu, Hao; Liu, Meng; Luo, Ai-Ping Xu, Wen-Cheng

    2014-10-20

    We reported on the femtosecond pulse generation from an erbium-doped fiber (EDF) laser by using microfiber-based gold nanorods (GNRs) as saturable absorber (SA). By virtue of the geometric characteristic of microfiber-based GNRs, the optical damage threshold of GNRs-SA could be greatly enhanced. The microfiber-based GNRs-SA shows a modulation depth of 4.9% and a nonsaturable loss of 21.1%. With the proposed GNRs-SA, the fiber laser emitted a mode-locked pulse train with duration of ∼887 fs. The obtained results demonstrated that the GNRs deposited microfiber could indeed serve as a high-performance SA towards the practical applications in the field of ultrafast photonics.

  6. Femtosecond Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Bock, Katherine J.

    This thesis focuses on research I have done on ytterbium-doped femtosecond fiber lasers. These lasers operate in the near infrared region, lasing at 1030 nm. This wavelength is particularly important in biomedical applications, which includes but is not limited to confocal microscopy and ablation for surgical incisions. Furthermore, fiber lasers are advantageous compared to solid state lasers in terms of their cost, form factor, and ease of use. Solid state lasers still dominate the market due to their comparatively high energy pulses. High energy pulse generation in fiber lasers is hindered by either optical wave breaking or by multipulsing. One of the main challenges for fiber lasers is to overcome these limitations to achieve high energy pulses. The motivation for the work done in this thesis is increasing the output pulse peak power and energy. The main idea of the work is that decreasing the nonlinearity that acts on the pulse inside the cavity will prevent optical wave breaking, and thus will generate higher energy pulses. By increasing the output energy, ytterbium-doped femtosecond fiber lasers can be competitive with solid state lasers which are used commonly in research. Although fiber lasers tend to lack the wavelength tuning ability of solid state lasers, many biomedical applications take advantage of the 1030 microm central wavelength of ytterbium-doped fiber lasers, so the major limiting factor of fiber lasers in this field is simply the output power. By increasing the output energy without resorting to external amplification, the cavity is optimized and cost can remain low and economical. During verification of the main idea, the cavity was examined for possible back-reflections and for components with narrow spectral bandwidths which may have contributed to the presence of multipulsing. Distinct cases of multipulsing, bound pulse and harmonic mode-locking, were observed and recorded as they may be of more interest in the future. The third

  7. Magnetic field sensor based on fiber Bragg grating with a spiral microgroove ablated by femtosecond laser.

    PubMed

    Dai, Yutang; Yang, Minghong; Xu, Gang; Yuan, Yinquan

    2013-07-15

    A novel magnetic field sensor based on Terfenol-D coated fiber Bragg grating with spiral microstructure was proposed and demonstrated. Through a specially-designed holder, the spiral microstructure was ablated into the fiber Bragg grating (FBG) cladding by femtosecond laser. Due to the spiral microstructure, the sensitivity of FBG coated with magnetostrictive film was enhanced greatly. When the spiral pitch is 50 μm and microgroove depth is 13.5 μm, the sensitivity of the magnetic field sensor is roughly 5 times higher than that of non-microstructured standard FBG. The response to magnetic field is reversible, and could be applicable for magnetic field detection.

  8. Vector rectangular-shape laser based on reduced graphene oxide interacting with a long fiber taper.

    PubMed

    Gao, Lei; Zhu, Tao; Huang, Wei; Zeng, Jing

    2014-10-01

    A vector dual-wavelength rectangular-shape laser (RSL) based on a long fiber taper deposited with reduced graphene oxide is proposed, where nonlinearity is enhanced due to a large evanescent-field-interacting length and strong field confinement of an 8 mm fiber taper with a waist diameter of 4 μm. Graphene flakes are deposited uniformly on the taper waist with light pressure effect, so this structure guarantees both excellent saturable absorption and high nonlinearity. The RSL with a repetition rate of 7.9 MHz shows fast polarization switching in two orthogonal polarization directions, and temporal and spectral characteristics are investigated. PMID:25322232

  9. Graphene-based passively Q-switched dual-wavelength erbium-doped fiber laser.

    PubMed

    Luo, Zhengqian; Zhou, Min; Weng, Jian; Huang, Guoming; Xu, Huiying; Ye, Chenchun; Cai, Zhiping

    2010-11-01

    We demonstrate a compact Q-switched dual-wavelength erbium-doped fiber (EDF) laser based on graphene as a saturable absorber (SA). By optically driven deposition of graphene on a fiber core, the SA is constructed and inserted into a diode-pumped EDF laser cavity. Also benefiting from the strong third-order optical nonlinearity of graphene to suppress the mode competition of EDF, a stable dual-wavelength Q-switching operation has been achieved using a two-reflection peak fiber Bragg grating as the external cavity mirror. The Q-switched EDF laser has a low pump threshold of 6.5 mW at 974 nm and a wide range of pulse-repetition rate from 3.3 to 65.9 kHz. The pulse duration and the pulse energy have been characterized. This is, to the best of our knowledge, the first demonstration of a graphene-based Q-switched laser.

  10. Photonic methods of millimeter-wave generation based on Brillouin fiber laser

    NASA Astrophysics Data System (ADS)

    Al-Dabbagh, R. K.; Al-Raweshidy, H. S.

    2016-05-01

    In optical communication link, generation and delivering millimeter-wave (mm-waves) in radio over fiber (RoF) systems has limitation due to fiber non-linearity effects. To solve this problem, photonic methods of mm-wave generation based on characterizations of Brillouin fiber laser are proposed in this work for the first time. Three novel photonic approaches for mm-wave generation methods based on Brillouin fiber laser and phase modulator are proposed and demonstrated by simulation. According to our theoretical analysis and simulation, mm-waves with frequency up to 80 GHz and good signal to noise ratio (SNR) up to 90 dB are generated by new and cost effective methods of generation that make them suitable for applications of the fifth generation (5G) networks. The proposed configurations increase the stability and the quality of the mm-wave generation system by using a single laser source as a pump wave and the fiber non-linearity effects are reduced. A key advantage of this research is that proposed a number of very simple generation methods and cost effective which only use standard components of optical telecommunications. Stimulated Brillouin Scattering (SBS) effect that exists in the optical fiber is studied with the characterization of phase modulator. An all optically stable mm-wave carriers are achieved successfully in the three different methods with different frequencies from 20 GHz up to 80 GHz. Simulation results show that all these carriers have low phase noise, good SNR ranging between 60 and 90 dB and tuning capability in comparison with previous methods reported. This makes them suitable for mm-wave transmission in RoF systems to transmit data in the next generation networks.

  11. Multi-modal label-free imaging based on a femtosecond fiber laser

    PubMed Central

    Xie, Ruxin; Su, Jue; Rentchler, Eric C.; Zhang, Ziyan; Johnson, Carey K.; Shi, Honglian; Hui, Rongqing

    2014-01-01

    We demonstrate multi-mode microscopy based on a single femtosecond fiber laser. Coherent anti-Stokes Raman scattering (CARS), stimulated Raman scattering (SRS) and photothermal images can be obtained simultaneously with this simplified setup. Distributions of lipid and hemoglobin in sliced mouse brain samples and blood cells are imaged. The dependency of signal amplitude on the pump power and pump modulation frequency is characterized, which allows to isolate the impact from different contributions. PMID:25071972

  12. High-power fiber laser based on a non filamented-core fully-aperiodic large pitch fiber

    NASA Astrophysics Data System (ADS)

    Benoit, A.; Dauliat, R.; Darwich, D.; Jamier, R.; Grimm, S.; Kobelke, Jens; Schuster, K.; Roy, P.

    2016-03-01

    In this communication, the authors report on the first high power emission obtained using a solid non-filamented core fully-aperiodic large pitch fiber manufactured by the REPUSIL method which is based on the sintering and vitrification of micrometric doped silica powders. Using a simple laser cavity, an average output power of 252 W was achieved for the first time in such a fiber with an available pump power of 400 W, corresponding to an optical-to-optical efficiency of 63 %. The M2 measurements have shown an excellent beam quality with values close to 1.4 at full power and lower than 1.3 for signal power lower than 215 W.

  13. Implementation of a widely tunable microwave signal generator based on dual-polarization fiber grating laser.

    PubMed

    Yuan, Qiang; Liang, Yizhi; Jin, Long; Cheng, Linghao; Guan, Bai-Ou

    2015-02-01

    In this paper, we demonstrate the implementation of a widely tunable microwave signal generator based on a dual-polarization fiber grating laser. The laser contains two strong, wavelength-matched Bragg gratings photoinscribed in an Er-doped fiber and emits two polarization modes when pumped with a 980 nm laser diode. By beating the two modes, a microwave signal with a signal-to-noise ratio over 60 dB can be obtained. For a free running laser the fluctuations in intensity and frequency of the microwave signal are ±1  dB and ±5  kHz, respectively, and the noise level is about -40  dBc/Hz at 1 kHz. The frequency can be continuously tuned from 1.8 to 15.1 GHz, by transversely loading the laser cavity and changing the intracavity birefringence by use of a piezoelectric transducer-based mechanical device. The measured response time rate of tuning is about 90 MHz/μs and the intensity fluctuation at different frequencies is less than ±1.5  dB. The frequency fluctuation under loading is controlled within 1 MHz by introducing an electrical feedback. PMID:25967802

  14. Fiber based infrared lasers and their applications in medicine, spectroscopy and metrology

    NASA Astrophysics Data System (ADS)

    Alexander, Vinay Varkey

    In my thesis, I have demonstrated the development of fiber based infrared lasers and devices for applications in medicine, spectroscopy and metrology. One of the key accomplishments presented in this thesis for medical applications is the demonstration of a focused infrared laser to perform renal denervation both in vivo and in vitro. Hypertension is a significant health hazard in the US and throughout the world, and the laser based renal denervation procedure may be a potential treatment for resistant hypertension. Compared to current treatment modalities, lasers may be able to perform treatments with lesser collateral tissue damage and quicker treatment times helping to reduce patient discomfort and pain. An additional medical application demonstrated in this thesis is the use of infrared fiber lasers to damage sebaceous glands in human skin as a potential treatment for acne. Another significant work presented in this thesis is a field trial performed at the Wright Patterson Air Force Base using a Short Wave Infrared (SWIR) Supercontinuum (SC) laser as an active illumination source for long distance reflectance measurements. In this case, an SC laser developed as part of this thesis is kept on a 12 story tower and propagated through the atmosphere to a target kept 1.6 km away and used to perform spectroscopy measurements. In the future this technology may permit 24/7 surveillance based on looking for the spectral signatures of materials. Beyond applications in defense, this technology may have far reaching commercial applications as well, including areas such as oil and natural resources exploration. Beyond these major contributions to the state-of-the-art, this thesis also describes other significant studies such as power scalability of SWIR SC sources and non-invasive measurement of surface roughness.

  15. Q-switched all-fiber laser based on magnetostriction modulation of a Bragg grating.

    PubMed

    Pérez-Millán, P; Díez, A; Andrés, M; Zalvidea, D; Duchowicz, R

    2005-06-27

    We report an actively Q-switched all-fiber laser based on magnetostriction modulation of a Bragg grating. The laser employs a pair of Bragg gratings as reflective mirrors, one of which is bonded to a magnetostrictive element. Lengthening of the magnetostrictive element when a magnetic field is applied shifts the Bragg wavelength of the grating, allowing control of the Q-factor of the cavity and, thus, performing active Q-switching. The magnetostrictive modulator is small, compact and requires less than 300 mW electrical drive power. Using erbium-doped fiber and a maximum pump power of 120 mW, Q-switch pulses of more than 1 W peak power were obtained, with a pulse repetition rate that can be continuously varied from 1 Hz to 125 kHz. PMID:19498492

  16. Harmonic mode locking of bound-state solitons fiber laser based on MoS(2) saturable absorber.

    PubMed

    Wang, Yadong; Mao, Dong; Gan, Xuetao; Han, Lei; Ma, Chaojie; Xi, Teli; Zhang, Yi; Shang, Wuyun; Hua, Shijia; Zhao, Jianlin

    2015-01-12

    We present a kind of harmonic mode locking of bound-state solitons in a fiber laser based on molybdenum disulfide (MoS(2)) saturable absorber (SA). The mode locker is fabricated by depositing MoS(2) nanosheets on a D-shaped fiber (DF). In the fiber laser, two solitons form the bound-state pulses with a temporal separation of 3.4 ps, and the bound-state pulses are equally distributed at a repetition rate of 125 MHz, corresponding to 14th harmonics of fundamental cavity repetition rate (8.968 MHz). Single- and multiple-pulses emissions are also observed by changing the pump power and optimizing the DF based MoS(2) SA. Our experiment demonstrates an interesting operation regime of mode-locked fiber laser, and shows that DF based MoS(2) SA can work as a promising high-power mode locker in ultrafast lasers. PMID:25835667

  17. Wideband ultrafast fiber laser sources for OCT and metrology

    NASA Astrophysics Data System (ADS)

    Nishizawa, Norihiko

    2016-09-01

    Fiber lasers, which use optical fibers as ideal waveguides, have been attracting a great deal of attention as stable, practical, and maintenance-free lasers. Using a combination of an ultrashort-pulse fiber laser and a nonlinear fiber, we can realize wideband highly functional ultrafast fiber laser sources. The generation of ultrashort pulses with wide wavelength tunability and supercontinua based on fiber lasers and nonlinear fibers has been demonstrated. These techniques are useful for laser applications, especially for imaging and metrology. In this topical review, the fundamentals of and recent progress in wideband ultrafast fiber laser sources and their applications are reviewed mainly based on the author’s work. First, a new pulse source based on a passively-mode-locked ultrashort-pulse fiber laser using carbon nanotubes is explained. Next, the development of wideband ultrafast fiber laser sources and their applications in ultrahigh-resolution optical coherence tomography, optical frequency combs, and nonlinear microscopy are reviewed.

  18. Tunable single frequency fiber laser based on FP-LD injection locking.

    PubMed

    Zhang, Aiqin; Feng, Xinhuan; Wan, Minggui; Li, Zhaohui; Guan, Bai-ou

    2013-05-20

    We propose and demonstrate a tunable single frequency fiber laser based on Fabry Pérot laser diode (FP-LD) injection locking. The single frequency operation principle is based on the fact that the output from a FP-LD injection locked by a multi-longitudinal-mode (MLM) light can have fewer longitudinal-modes number and narrower linewidth. By inserting a FP-LD in a fiber ring laser cavity, single frequency operation can be possibly achieved when stable laser oscillation established after many roundtrips through the FP-LD. Wavelength switchable single frequency lasing can be achieved by adjusting the tunable optical filter (TOF) in the cavity to coincide with different mode of the FP-LD. By adjustment of the drive current of the FP-LD, the lasing modes would shift and wavelength tunable operation can be obtained. In experiment, a wavelength tunable range of 32.4 nm has been obtained by adjustment of the drive current of the FP-LD and a tunable filter in the ring cavity. Each wavelength has a side-mode suppression ratio (SMSR) of at least 41 dB and a linewidth of about 13 kHz.

  19. Wide bandwidth dual-frequency ultrasound measurements based on fiber laser sensing technology.

    PubMed

    Lyu, Chengang; Liu, Ying; Wu, Chuang

    2016-07-01

    A dual-frequency ultrasound measurement system based on a distributed Bragg reflector (DBR) fiber laser sensor in a liquid medium was presented. To compare the dual-frequency measurement performance of a DBR fiber laser acoustic sensor with that of a piezoelectric (PZT) ultrasound sensor, two experiments were performed. First, we fixed the driving frequencies of two ultrasound signals at 3 and 5 MHz, and decreased the driving voltage from 15 to 3 V. The outputs of the DBR acoustic sensor show flat-balanced response to dual-frequencies, compared with the PZT acoustic sensor whose response to one of the dual-frequency signals (5 MHz in this paper) has been covered by noise at low acoustic pressure. Then we increased the acoustic pressure by fixing the driving voltage at 20 V, and changed the frequency spacing between the two ultrasound signals. By analyzing the frequency response, sensitivity, signal-to-noise ratio, and noise equivalent pressure of two acoustic sensors under different frequencies, we found that the response of the DBR sensor to wideband dual-frequency is stable, while the response of the PZT sensor deteriorates sharply with increasing frequency spacing. The results demonstrate that the DBR fiber laser sensor performs better for wide bandwidth dual-frequency ultrasound measurements.

  20. Multiwall carbon nanotube polyvinyl alcohol-based saturable absorber in passively Q-switched fiber laser.

    PubMed

    Ahmad, H; Ismail, M F; Hassan, S N M; Ahmad, F; Zulkifli, M Z; Harun, S W

    2014-10-20

    In this work, we demonstrated a compact Q-switched erbium-doped fiber laser capable of generating high-energy pulses using a newly developed multiwall carbon nanotube (CNT) polyvinyl alcohol (PVA) thin film based saturable absorber. Q-switched pulse operation is obtained by sandwiching the thin film between two fiber ferrules forming a saturable absorber. A saturable absorber with 1.25 wt. % of PVA concentration shows a consistency in generating pulsed laser with a good range of tunable repetition rate, shortest pulse width, and produces a high pulse energy and peak power. The pulse train generated has a maximum repetition rate of 29.9 kHz with a corresponding pulse width of 3.49 μs as a function of maximum pump power of 32.15 mW. The maximum average output power of the Q-switched fiber laser system is 1.49 mW, which translates to a pulse energy of 49.8 nJ. The proposed method of multiwall CNT/PVA thin film fabrication is low in cost and involves uncomplicated processes. PMID:25402790

  1. Wide bandwidth dual-frequency ultrasound measurements based on fiber laser sensing technology.

    PubMed

    Lyu, Chengang; Liu, Ying; Wu, Chuang

    2016-07-01

    A dual-frequency ultrasound measurement system based on a distributed Bragg reflector (DBR) fiber laser sensor in a liquid medium was presented. To compare the dual-frequency measurement performance of a DBR fiber laser acoustic sensor with that of a piezoelectric (PZT) ultrasound sensor, two experiments were performed. First, we fixed the driving frequencies of two ultrasound signals at 3 and 5 MHz, and decreased the driving voltage from 15 to 3 V. The outputs of the DBR acoustic sensor show flat-balanced response to dual-frequencies, compared with the PZT acoustic sensor whose response to one of the dual-frequency signals (5 MHz in this paper) has been covered by noise at low acoustic pressure. Then we increased the acoustic pressure by fixing the driving voltage at 20 V, and changed the frequency spacing between the two ultrasound signals. By analyzing the frequency response, sensitivity, signal-to-noise ratio, and noise equivalent pressure of two acoustic sensors under different frequencies, we found that the response of the DBR sensor to wideband dual-frequency is stable, while the response of the PZT sensor deteriorates sharply with increasing frequency spacing. The results demonstrate that the DBR fiber laser sensor performs better for wide bandwidth dual-frequency ultrasound measurements. PMID:27409190

  2. Large anomalous-dispersion mode-locked fiber laser based on a chirped fiber Bragg grating pair

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Yan, Yaxi; Hu, Chengzhi; Wu, Bo; Shen, Yonghang

    2016-10-01

    A carbon-nanotube mode-locked erbium fiber laser with large net anomalous dispersion is presented. A chirped fiber Bragg grating (CFBG) pair is incorporated to increase the net-cavity anomalous dispersion and soliton splitting threshold. Self-started mode-locked laser produces stable pulses with repetition rate of 9.26 MHz. Laser spectrum is centered at ~1560 nm with 3 dB bandwidth of 0.43 nm. The typical output pulse energy and duration is 0.21 nJ and 8.05 ps, respectively.

  3. Demonstration of multi-wavelength tunable fiber lasers based on a digital micromirror device processor.

    PubMed

    Ai, Qi; Chen, Xiao; Tian, Miao; Yan, Bin-bin; Zhang, Ying; Song, Fei-jun; Chen, Gen-xiang; Sang, Xin-zhu; Wang, Yi-quan; Xiao, Feng; Alameh, Kamal

    2015-02-01

    Based on a digital micromirror device (DMD) processor as the multi-wavelength narrow-band tunable filter, we demonstrate a multi-port tunable fiber laser through experiments. The key property of this laser is that any lasing wavelength channel from any arbitrary output port can be switched independently over the whole C-band, which is only driven by single DMD chip flexibly. All outputs display an excellent tuning capacity and high consistency in the whole C-band with a 0.02 nm linewidth, 0.055 nm wavelength tuning step, and side-mode suppression ratio greater than 60 dB. Due to the automatic power control and polarization design, the power uniformity of output lasers is less than 0.008 dB and the wavelength fluctuation is below 0.02 nm within 2 h at room temperature. PMID:25967765

  4. Demonstration of multi-wavelength tunable fiber lasers based on a digital micromirror device processor.

    PubMed

    Ai, Qi; Chen, Xiao; Tian, Miao; Yan, Bin-bin; Zhang, Ying; Song, Fei-jun; Chen, Gen-xiang; Sang, Xin-zhu; Wang, Yi-quan; Xiao, Feng; Alameh, Kamal

    2015-02-01

    Based on a digital micromirror device (DMD) processor as the multi-wavelength narrow-band tunable filter, we demonstrate a multi-port tunable fiber laser through experiments. The key property of this laser is that any lasing wavelength channel from any arbitrary output port can be switched independently over the whole C-band, which is only driven by single DMD chip flexibly. All outputs display an excellent tuning capacity and high consistency in the whole C-band with a 0.02 nm linewidth, 0.055 nm wavelength tuning step, and side-mode suppression ratio greater than 60 dB. Due to the automatic power control and polarization design, the power uniformity of output lasers is less than 0.008 dB and the wavelength fluctuation is below 0.02 nm within 2 h at room temperature.

  5. Low-noise Brillouin random fiber laser with a random grating-based resonator.

    PubMed

    Xu, Yanping; Gao, Song; Lu, Ping; Mihailov, Stephen; Chen, Liang; Bao, Xiaoyi

    2016-07-15

    A novel Brillouin random fiber laser (BRFL) with the random grating-based Fabry-Perot (FP) resonator is proposed and demonstrated. Significantly enhanced random feedback from the femtosecond laser-fabricated random grating overwhelms the Rayleigh backscattering, which leads to efficient Brillouin gain for the lasing modes and reduced lasing threshold. Compared to the intensity and frequency noises of the Rayleigh feedback resonator, those of the proposed random laser are effectively suppressed due to the reduced resonating modes and mode competition resulting from the random grating-formed filters. Using the heterodyne technique, the linewidth of the coherent random lasing spike is measured to be ∼45.8  Hz. PMID:27420494

  6. 1.2-kW single-mode fiber laser based on 100-W high-brightness pump diodes

    NASA Astrophysics Data System (ADS)

    Yu, Hongbo; Kliner, Dahv A. V.; Liao, Kai-Hsiu; Segall, Jeff; Muendel, Martin H.; Morehead, James J.; Shen, Jane; Kutsuris, Matt; Luu, Johnny; Franke, Justin; Nguyen, Kelvin; Woods, Dave; Vance, Fred; Vecht, David; Meng, David; Duesterberg, Richard; Xu, Lei; Skidmore, Jay; Peters, Matthew; Guerin, Nicolas; Guo, James; Cheng, Jane; Du, Jihua; Johnson, Brad; Yin, Dongliang; Hsieh, Allen; Cheng, Peter; Demir, Abdullah; Cai, Jason; Gurram, Rupa; Lee, Kong-Weng; Raju, Reddy; Zou, Daniel; Srinivasan, Raman; Saini, Mandeep; Zavala, Laura; Rossin, Victor; Zucker, Erik P.; Ishiguro, Hiroaki; Sako, Hiroshi

    2012-02-01

    We have demonstrated a monolithic (fully fused), 1.2-kW, Yb-doped fiber laser with near-single-mode beam quality. This laser employs a new generation of high-brightness, fiber-coupled pump sources based on spatially multiplexed single emitters, with each pump providing 100 W at 915 nm within 0.15 NA from a standard 105/125 μm fiber. The fiber laser is end pumped through the high-reflector FBG using a 19:1 fused-fiber pump combiner, eliminating the need for pump/signal combiners. The output wavelength is 1080 nm, with a linewidth of < 0.5 nm FWHM. A peak power of 1.5 kW was reached in modulated operation (1-ms pulse duration) with M2 < 1.2.

  7. Fiber laser cladding of nickel-based alloy on cast iron

    NASA Astrophysics Data System (ADS)

    Arias-González, F.; del Val, J.; Comesaña, R.; Penide, J.; Lusquiños, F.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pou, J.

    2016-06-01

    Gray cast iron is a ferrous alloy characterized by a carbon-rich phase in form of lamellar graphite in an iron matrix while ductile cast iron presents a carbon-rich phase in form of spheroidal graphite. Graphite presents a higher laser beam absorption than iron matrix and its morphology has also a strong influence on thermal conductivity of the material. The laser cladding process of cast iron is complicated by its heterogeneous microstructure which generates non-homogeneous thermal fields. In this research work, a comparison between different types of cast iron substrates (with different graphite morphology) has been carried out to analyze its impact on the process results. A fiber laser was used to generate a NiCrBSi coating over flat substrates of gray cast iron (EN-GJL-250) and nodular cast iron (EN-GJS-400-15). The relationship between processing parameters (laser irradiance and scanning speed) and geometry of a single laser track was examined. Moreover, microstructure and composition were studied by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD). The hardness and elastic modulus were analyzed by means of micro- and nanoindentation. A hardfacing coating was generated by fiber laser cladding. Suitable processing parameters to generate the Ni-based alloy coating were determined. For the same processing parameters, gray cast iron samples present higher dilution than cast iron samples. The elastic modulus is similar for the coating and the substrate, while the Ni-based coating obtained presents a significantly superior hardness than cast iron.

  8. Tm-based fiber-laser system with more than 200  MW peak power.

    PubMed

    Stutzki, Fabian; Gaida, Christian; Gebhardt, Martin; Jansen, Florian; Jauregui, Cesar; Limpert, Jens; Tünnermann, Andreas

    2015-01-01

    Tm-based fiber-laser systems are an attractive concept for the development of high-performance laser sources in the spectral region around 2 μm wavelength. Here we present a system delivering a pulse-peak power higher than 200 MW in combination with 24 W average power and 120 μJ pulse energy. Key components enabling this performance level are a Tm-doped large-pitch fiber with a mode-field diameter of 65 μm, highly efficient dielectric gratings, and a Tm-based fiber oscillator operating in the stretched-pulse regime. PMID:25531595

  9. A fiber DBR laser based vector hydrophone for ultrasonic medical applications

    NASA Astrophysics Data System (ADS)

    Wang, Han; Guo, Xi; Gao, Jingyi; Lyu, Chengang

    2015-04-01

    An ultrasonic hydrophone based on a dual polarization distributed Bragg reflector (DBR) fiber laser is described, and its application to detecting the vector medical ultrasound is demonstrated. The principle of the hydrophone is based on the detection of output beat frequency signal modulated by ultrasound. The amplitude, frequency and orientation of the ultrasound can be determined by the using the upper and lower sideband frequency. It has been found that the hydrophone has an orientation recognizable ability which the piezoelectric ultrasonic immersion transducer doesn't have. It suggests that the type of hydrophone can provide an alternative to piezoelectric hydrophone technology.

  10. Q-switched mode-locked erbium-doped fiber laser based on topological insulator Bi(2)Se(3) deposited fiber taper.

    PubMed

    Gao, Lei; Huang, Wei; Zhang, Jing Dong; Zhu, Tao; Zhang, Han; Zhao, Chu Jun; Zhang, Wei; Zhang, Hua

    2014-08-10

    We have demonstrated the passive Q-switching mode-locking operation in an erbium-doped fiber (EDF) laser by using topological insulator Bi(2)Se(3) deposited on fiber taper, whose damage threshold can be further increased by the large evanescent field interacting length. Due to the low saturation intensity, stable Q-switched mode-locked fiber lasers centered at 1562 nm can be generated at a pump power of 10 mW. The temporal and spectral characteristics for different pump strengths have also been investigated. To the best of our knowledge, it is the first time a Q-switched mode-locked EDF laser based on the fiber taper deposited by Bi(2)Se(3) was generated. PMID:25320919

  11. Q-switched mode-locked erbium-doped fiber laser based on topological insulator Bi(2)Se(3) deposited fiber taper.

    PubMed

    Gao, Lei; Huang, Wei; Zhang, Jing Dong; Zhu, Tao; Zhang, Han; Zhao, Chu Jun; Zhang, Wei; Zhang, Hua

    2014-08-10

    We have demonstrated the passive Q-switching mode-locking operation in an erbium-doped fiber (EDF) laser by using topological insulator Bi(2)Se(3) deposited on fiber taper, whose damage threshold can be further increased by the large evanescent field interacting length. Due to the low saturation intensity, stable Q-switched mode-locked fiber lasers centered at 1562 nm can be generated at a pump power of 10 mW. The temporal and spectral characteristics for different pump strengths have also been investigated. To the best of our knowledge, it is the first time a Q-switched mode-locked EDF laser based on the fiber taper deposited by Bi(2)Se(3) was generated.

  12. Interrogation of a wavelength tunable fiber Bragg grating sensor based ring laser for dynamic strain monitoring

    NASA Astrophysics Data System (ADS)

    Balogun, Oluwaseyi; Zhu, Yinian; Krishnaswamy, Sridhar

    2010-03-01

    Fiber Bragg gratings (FBGs) are wavelength selective optical reflectors with excellent strain sensitivity and small sensing footprint, which makes them suitable as diagnostic sensors for structural health monitoring applications. In this work, we explore the narrowband wavelength selectivity of FBGs for optical feedback in a tunable fiber ring laser. The fiber ring laser consists of an erbium doped fiber laser that is pumped with a Raman laser (980 nm) to produce population inversion and amplified spontaneous emission (ASE) in the C-band. The ASE light is used to illuminate a FBG sensor connected to the ring, and the reflected light from the sensor is fed back into the laser cavity to produce stimulated emission at the instantaneous center wavelength of the sensor. As the wavelength of the sensor shifts due mechanical or thermal strains, the wavelength of the optical output from the ring laser shifts accordingly. By combining the ring laser with a dynamic spectral demodulator for optical readout, the instantaneous wavelength of the ring laser is tracked with high temporal resolution. The fiber ring laser system offers several potential advantages in the diagnostic sensing of mechanical strains for SHM applications including, fully integrated laser and sensor system, high source power levels at the sensor wavelength, narrow spectral line-width, coherent spectral demodulation, and low system costs. In this work, we present experimental results that detail the feasibility of dynamic spectral tuning of the fiber ring laser at frequencies up to hundreds of kilohertz using a single FBG sensing element. Using multiple sensing elements, the fiber ring laser system would allow for active monitoring of dynamic strains in a multi-point sensor array configuration, which is particularly suitable for the localization of high frequency mechanical strains produced by impact loading and cracking events in structures.

  13. Multimode fiber laser for simultaneous measurement of strain and temperature based on beat frequency demodulation.

    PubMed

    Gao, Liang; Chen, Lin; Huang, Long; Chen, Xiangfei

    2012-09-24

    A multimode fiber laser sensor system for simultaneous measurement of strain and temperature is proposed and demonstrated. Because of the long cavity and birefringence, longitudinal mode beat frequency and polarization mode beat frequency are achieved in the beat frequency signals of the multimode fiber laser. The strain and temperature can be obtained by monitoring both of them for their different strain and temperature responses. The experimental measurement errors are within ± 16.2 με and ± 1.9 °C. The usage of only one fiber laser and one demodulation system makes the system simple, cost-effective and portable.

  14. Musical instrument pickup based on a laser locked to an optical fiber resonator.

    PubMed

    Avino, Saverio; Barnes, Jack A; Gagliardi, Gianluca; Gu, Xijia; Gutstein, David; Mester, James R; Nicholaou, Costa; Loock, Hans-Peter

    2011-12-01

    A low-noise transducer based on a fiber Fabry-Perot (FFP) cavity was used as a pickup for an acoustic guitar. A distributed feedback (DFB) laser was locked to a 25 MHz-wide resonance of the FFP cavity using the Pound-Drever-Hall method. The correction signal was used as the audio output and was preamplified and sampled at up to 96 kHz. The pickup system is largely immune against optical noise sources, exhibits a flat frequency response from the infrasound region to about 25 kHz, and has a distortion-free audio output range of about 50 dB. PMID:22273897

  15. Tunable fiber laser based photoacoustic spectrometer for breath ammonia analysis during hemodialysis

    NASA Astrophysics Data System (ADS)

    Wang, J. W.; Xie, H.; Liang, L. R.; Zhang, W.; Peng, W.; Yu, Q. X.

    2011-11-01

    A photoacoustic (PA) spectrometer based on a near-IR tunable fiber laser is developed and used for breath ammonia analysis. We successfully measured the breath ammonia level variation of six patients with end-stage renal disease while they were undergoing hemodialysis in the hospital. The measurement results showed that the initial concentration level of the breath ammonia were from 1600 to 2200 ppb before dialysis treatment, the levels decreased to 200-600 ppb in the end stage of dialysis, which close to the levels of healthy persons. Further improvement and applications of this PA spectrometer are discussed.

  16. Fiber-based, trace-gas, laser transmitter technology development for space

    NASA Astrophysics Data System (ADS)

    Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzales, Brayler; Han, Lawrence; Numata, Kenji; Storm, Mark; Abshire, James

    2015-09-01

    NASA's Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument over several years to demonstrate the efficacy of the instrumentation and measurement technique and to link the science models to the instrument performance. The ultimate goal is to make space-based satellite measurements with global coverage. In order to accomplish this, we must demonstrate the technology readiness and performance of the components as well as demonstrate the required power-scaling to make the link with the required signal-to-noise-ratio (SNR). To date, all the instrument components have been shown to have the required performance with the exception of the laser transmitter. In this program we are working on a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture where we will develop a ruggedized package and perform the relevant environmental tests to demonstrate TRL-6. In this paper we will review our transmitter architecture and progress on the performance and packaging of the laser transmitter.

  17. Fiber-Based, Trace-Gas, Laser Transmitter Technology Development for Space

    NASA Technical Reports Server (NTRS)

    Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzalez, Brayler; Han, Lawrence; Numata, Kenji; Storm, Mark; Abshire, James

    2015-01-01

    NASA’s Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument over several years to demonstrate the efficacy of the instrumentation and measurement technique and to link the science models to the instrument performance. The ultimate goal is to make space-based satellite measurements with global coverage. In order to accomplish this, we must demonstrate the technology readiness and performance of the components as well as demonstrate the required power-scaling to make the link with the required signal-to-noise-ratio (SNR). To date, all the instrument components have been shown to have the required performance with the exception of the laser transmitter.In this program we are working on a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture where we will develop a ruggedized package and perform the relevant environmental tests to demonstrate TRL-6. In this paper we will review our transmitter architecture and progress on the performance and packaging of the laser transmitter.

  18. External cavity diode laser based upon an FBG in an integrated optical fiber platform.

    PubMed

    Lynch, Stephen G; Holmes, Christopher; Berry, Sam A; Gates, James C; Jantzen, Alexander; Ferreiro, Teresa I; Smith, Peter G R

    2016-04-18

    An external cavity diode laser is demonstrated using a Bragg grating written into a novel integrated optical fiber platform as the external cavity. The cavity is fabricated using flame-hydrolysis deposition to bond a photosensitive fiber to a silica-on-silicon wafer, and a grating written using direct UV-writing. The laser operates on a single mode at the acetylene P13 line (1532.83 nm) with 9 mW output power. The noise properties of the laser are characterized demonstrating low linewidth operation (< 14 kHz) and superior relative intensity noise characteristics when compared to a commercial tunable external cavity diode laser. PMID:27137276

  19. Diffractive-optics-based beam combination of a phase-locked fiber laser array.

    PubMed

    Cheung, Eric C; Ho, James G; Goodno, Gregory D; Rice, Robert R; Rothenberg, Josh; Thielen, Peter; Weber, Mark; Wickham, Michael

    2008-02-15

    A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers.

  20. Discrete bisoliton fiber laser

    PubMed Central

    Liu, X. M.; Han, X. X.; Yao, X. K.

    2016-01-01

    Dissipative solitons, which result from the intricate balance between dispersion and nonlinearity as well as gain and loss, are of the fundamental scientific interest and numerous important applications. Here, we report a fiber laser that generates bisoliton – two consecutive dissipative solitons that preserve a fixed separation between them. Deviations from this separation result in its restoration. It is also found that these bisolitons have multiple discrete equilibrium distances with the quantized separations, as is confirmed by the theoretical analysis and the experimental observations. The main feature of our laser is the anomalous dispersion that is increased by an order of magnitude in comparison to previous studies. Then the spectral filtering effect plays a significant role in pulse-shaping. The proposed laser has the potential applications in optical communications and high-resolution optics for coding and transmission of information in higher-level modulation formats. PMID:27767075

  1. High-accuracy fiber optical microphone in a DBR fiber laser based on a nanothick silver diaphragm by self-mixing technique.

    PubMed

    Du, Zhengting; Lu, Liang; Zhang, Wenhua; Yang, Bo; Wu, Shuang; Zhao, Yunhe; Xu, Feng; Wang, Zhiping; Gui, Huaqiao; Liu, Jianguo; Yu, Benli

    2013-12-16

    A high-accuracy fiber optical microphone (FOM) is first applied by self-mixing technique in a DBR fiber laser based on a nanothick silver diaphragm. The nanothick silver diaphragm fabricated by the convenient and low cost electroless plating method is functioned as sensing diaphragm due to critically susceptible to the air vibration. Simultaneously, micro-vibration theory model of self-mixing interference fiber optical microphone is deduced based on quasi-analytical method. The dynamic property to frequencies and amplitudes are experimentally carried out to characterize the fabricated FOM and also the reproduced sound of news and music can clearly meet the ear of the people which shows the technique proposed in this paper guarantee steady, high signal-noise ratio operation and outstanding accuracy in the DBR fiber laser which is potential to medical and security applications such as real-time voice reproduction for throat and voiceprint verification. PMID:24514635

  2. High-accuracy fiber optical microphone in a DBR fiber laser based on a nanothick silver diaphragm by self-mixing technique.

    PubMed

    Du, Zhengting; Lu, Liang; Zhang, Wenhua; Yang, Bo; Wu, Shuang; Zhao, Yunhe; Xu, Feng; Wang, Zhiping; Gui, Huaqiao; Liu, Jianguo; Yu, Benli

    2013-12-16

    A high-accuracy fiber optical microphone (FOM) is first applied by self-mixing technique in a DBR fiber laser based on a nanothick silver diaphragm. The nanothick silver diaphragm fabricated by the convenient and low cost electroless plating method is functioned as sensing diaphragm due to critically susceptible to the air vibration. Simultaneously, micro-vibration theory model of self-mixing interference fiber optical microphone is deduced based on quasi-analytical method. The dynamic property to frequencies and amplitudes are experimentally carried out to characterize the fabricated FOM and also the reproduced sound of news and music can clearly meet the ear of the people which shows the technique proposed in this paper guarantee steady, high signal-noise ratio operation and outstanding accuracy in the DBR fiber laser which is potential to medical and security applications such as real-time voice reproduction for throat and voiceprint verification.

  3. A widely tunable fiber ring laser with closed loop control based on high-precision stepper motor

    NASA Astrophysics Data System (ADS)

    Wang, Li-li; Xin, Xiang-jun; Zhu, Lin-wei

    2016-05-01

    A tunable single-longitudinal mode erbium-doped fiber ring laser based on stepper motor and closed loop control is proposed and demonstrated. The system consists of an erbium-doped fiber (EDF), a tunable fiber Bragg grating (FBG) filter and a wavelength detector. The characteristics of output laser, such as output power, power stability and 3-dB linewidth, are investigated in the operation range of 1 531—1 569 nm. The repeated experimental results of the fiber laser show that the 3-dB linewidth is less than 17 ps, the side-mode suppression ratio ( SMSR) is up to 60 dB, the output power is up to 1.37 dBm, and the power variation is less than 0.61 dB.

  4. Ring cavity fiber laser based on Fabry-Pérot interferometer for high-sensitive micro-displacement sensing

    NASA Astrophysics Data System (ADS)

    Bai, Yan; Yan, Feng-ping; Liu, Shuo; Tan, Si-yu; Wen, Xiao-dong

    2015-11-01

    A ring cavity fiber laser based on Fabry-Pérot interferometer (FPI) is proposed and demonstrated experimentally for micro-displacement sensing. Simulation results show that the dips of the FPI transmission spectrum are sensitive to the cavity length of the FPI. With this characteristic, the relationship between wavelength shift and cavity length change can be established by means of the FPI with two aligned fiber end tips. The maximum sensitivity of 39.6 nm/μm is achieved experimentally, which is approximately 25 times higher than those in previous reports. The corresponding ring cavity fiber laser with the sensitivity for displacement measurement of about 6 nm/μm is implemented by applying the FPI as the filter. The proposed fiber laser has the advantages of simple structure, low cost and high sensitivity.

  5. Generating 2 micron continuous-wave ytterbium-doped fiber laser-based optical parametric effect

    NASA Astrophysics Data System (ADS)

    Paul, M. C.; Latiff, A. A.; Hisyam, M. B.; Rusdi, M. F. M.; Harun, S. W.

    2016-10-01

    We report an efficient method for generating a 2 micron laser based on an optical parametric oscillator (OPO). It uses a long piece of a newly developed double-clad ytterbium-doped fiber (YDF), which is obtained by doping multi-elements of ZrO2, CeO2 and CaO in a phospho-alumina-silica glass as a gain medium. The efficient 2 micron laser generation is successful due to the presence of partially crystalline Yb-doped ZrO2 nano-particles that serve as a nonlinear material in a linear cavity configuration and high watt-level pump power. Stable self-wavelength double lasing at 2122 nm with an efficiency of 7.15% is successfully recorded. At a maximum pump power of 4.1 W, the output power is about 201 mW.

  6. DFB fiber laser static strain sensor based on beat frequency interrogation with a reference fiber laser locked to a FBG resonator.

    PubMed

    Huang, Wenzhu; Feng, Shengwen; Zhang, Wentao; Li, Fang

    2016-05-30

    We report on a high-resolution static strain sensor developed with distributed feedback (DFB) fiber laser. A reference FBG resonator is used for temperature compensation. Locking another independent fiber laser to the resonator using the Pound-Drever-Hall technique results in a strain power spectral density better than Sε(f) = (4.6 × 10-21) ε2/Hz in the frequency range from 1 Hz to 1 kHz, corresponding to a minimum dynamic strain resolution of 67.8 pε/√Hz. This frequency stabilized fiber laser is proposed to interrogate the sensing DFB fiber laser by the beat frequency principle. As a reasonable DFB fiber laser setup is realized, a narrow beat frequency line-width of 3.23 kHz and a high beat frequency stability of 0.036 MHz in 15 minutes are obtained in the laboratory test, corresponding to a minimum static strain resolution of 270 pε. This is the first time that a sub-0.5 nε level for static strain measurement using DFB fiber laser is demonstrated.

  7. DFB fiber laser static strain sensor based on beat frequency interrogation with a reference fiber laser locked to a FBG resonator.

    PubMed

    Huang, Wenzhu; Feng, Shengwen; Zhang, Wentao; Li, Fang

    2016-05-30

    We report on a high-resolution static strain sensor developed with distributed feedback (DFB) fiber laser. A reference FBG resonator is used for temperature compensation. Locking another independent fiber laser to the resonator using the Pound-Drever-Hall technique results in a strain power spectral density better than Sε(f) = (4.6 × 10-21) ε2/Hz in the frequency range from 1 Hz to 1 kHz, corresponding to a minimum dynamic strain resolution of 67.8 pε/√Hz. This frequency stabilized fiber laser is proposed to interrogate the sensing DFB fiber laser by the beat frequency principle. As a reasonable DFB fiber laser setup is realized, a narrow beat frequency line-width of 3.23 kHz and a high beat frequency stability of 0.036 MHz in 15 minutes are obtained in the laboratory test, corresponding to a minimum static strain resolution of 270 pε. This is the first time that a sub-0.5 nε level for static strain measurement using DFB fiber laser is demonstrated. PMID:27410147

  8. Fiber-optic technologies in laser-based therapeutics: threads for a cure.

    PubMed

    Wang, Zheng; Chocat, Noémie

    2010-06-01

    In the past decade, novel fiber structures and material compositions have led to the introduction of new diagnostic and therapeutic tools. We review the structure, the material composition and the fabrication processes behind these novel fiber systems. Because of their structural flexibility, their compatibility with endoscopic appliances and their efficiency in laser delivery, these fiber systems have greatly extended the reach of a wide range of surgical lasers in minimally invasive procedures. Much research in novel fiber-optics delivery systems has been focused on the accommodation of higher optical powers and the extension to a broader wavelength range. Until recently, CO2 laser surgery, renowned for its precision and efficiency, was limited to open surgeries by the lack of delivery fibers. Hollow-core photonic bandgap fibers are assessed for their ability to transmit CO2 laser at surgical power level and for their applications in a range of clinical areas. Current fiber-delivery technologies for a number of laser surgery modalities and wavelengths are compared.

  9. Multiwavelength fiber laser for the fiber link monitoring system

    NASA Astrophysics Data System (ADS)

    Peng, Peng-Chun; Lee, Wei-Yun; Wu, Shin-Shian; Hu, Hsuan-Lun

    2013-10-01

    This work proposes a novel fiber link monitoring system that uses a multiwavelength fiber laser for wavelength-division-multiplexed (WDM) passive optical network (PON). The multiwavelength fiber laser is based on an erbium-doped fiber amplifier (EDFA) and a semiconductor optical amplifier (SOA). Experimental results show the feasibility using the system to monitor a fiber link with a high and stable signal-to-noise ratio (SNR) of over 26 dB. The link quality of downstream signals as well as the fiber link on WDM channels can be monitored in real time. Favorable carrier-to-noise ratio (CNR), composite second-order (CSO), and composite triple beat (CTB) performance metrics were obtained for cable television (CATV) signals that were transported through 25 km of standard single-mode fiber (SMF).

  10. Yb-doped silica-based laser fibers: correlation of photodarkening kinetics and related optical properties with the glass composition

    NASA Astrophysics Data System (ADS)

    Kirchhof, J.; Unger, S.; Jetschke, S.; Schwuchow, A.; Leich, M.; Reichel, V.

    2009-02-01

    In the last years, photodarkening in ytterbium doped silica based laser fibers turned out to be a critical factor for high power laser action. Several investigations have been carried out in order to characterize the time dependent increase of the fiber loss and to understand and model the complex optical phenomenon. Despite of progress in this field, there is still a lack of data concerning the detailed influence of fiber composition and preparation process parameters as well as concerning the role of atomic defects in the core glass. Here we report on investigations about the photodarkening in dependence on the glass composition of the fiber laser core. By MCVD, fibers with different codopants (additional to the active ytterbium doping) have been prepared in a well-defined manner, regarding process parameters and glass composition, and comprehensively characterized. In addition to the photodarkening measurements, further optical properties have been measured on the fibers and fiber performs, which are related to the photodarkening effect: intensity and spectral behaviour of the Yb3+ absorption and emission in the NIR, cooperative visible fluorescence, UV absorption and UV excited visible emission. The concentration of codopants which are commonly used for active and passive lightguide fibers (aluminium, germanium, phosphorus) was systematically varied and correlated with the optical properties.

  11. High-resolution fiber methane sensor based on diode laser and its data processing

    NASA Astrophysics Data System (ADS)

    Wei, Yubin; Zhang, Tingting; Li, Yanfang; Zhao, Yanjie; Wang, Chang; Liu, Tongyu

    2011-06-01

    Tunable diode laser absorption spectroscopy (TDLAS) based optical fiber methane sensing technology has a number of advantages compared with conventional electronic methane sensor device, such as high Precision, passive and intrinsically safe in explosive and hazardous environment as well as immune to electro-magnetic interference. In order to accurately measure the oxidation rate of coal mine ventilation air methane oxidizer system, and Meet requirements for accurate measurements to the oxidizer exhaust emissions, A Fiber optic methane monitor based on Distributed feedback tunable diode (DFB) laser of 1.65um central wavelength is demonstrated. We use a reflective chamber of only a 10cm effective optical path as sensing gas cell. By the data processing of fitting baseline method, we remove the effect of the baseline tilt of background Spectral. The system achieves 0 to 0.1% measure range and 5.8*10E-6 minimum detection sensitivity, and meets the requirements of high accuracy, real-time measure to the oxidizer exhaust emissions.

  12. Fiber laser based high-spectral resolution lidar for earth science measurements

    NASA Astrophysics Data System (ADS)

    Chen, Youming; Berkoff, Timothy; Kimpel, Frank; Storm, Mark; Hoff, Raymond; Gupta, Shantanu

    2013-03-01

    We present a special high spectral resolution lidar (HSRL) by using a novel tunable fiber based transmitter. The transmitter can produce 50μJ pulse energy at 1064nm and >25μJ pulse energy at 532nm with 10 kHz repetition rate, 5ns pulse width, respectively. A key advantage of the transmitter is the frequency-tunability. The laser can be tuned over the Iodine absorption lines from 1111 to 1104. The laser has a ~130MHz linewidth at 1064nm close to the transform limit linewidth ~ 88MHz for a pulse width of 5ns. Even though it was not frequency locked, the laser has very good frequency stability, which is on the order of ~200MHz over minutes. The beam quality M2 is less than 1.5. All the preliminary transmitter parameters meet the basic requirements of a HSRL. The transmitter was implemented in UMBC's lidar lab that includes a ceiling hatch to enable vertical propagation and viewing of transmitted laser beams into the atmosphere. The atmospheric measurement demonstrates good agreement of the signal to the model Rayleigh decay over the profile range with no significant deviations. Most importantly, these results show that the measurement successfully suppresses the Mie scattering from clouds while recovering the full molecular signal as expected.

  13. Fiber Laser Development for LISA

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Chen, Jeffrey R.

    2009-01-01

    We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable.

  14. Fiber laser development for LISA

    NASA Astrophysics Data System (ADS)

    Numata, Kenji; Chen, Jeffrey R.; Camp, Jordan

    2010-05-01

    We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064 nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100 kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable.

  15. Q-switched Tm3+-doped fiber laser with a micro-fiber based black phosphorus saturable absorber

    NASA Astrophysics Data System (ADS)

    Wang, Yazhou; Li, Jianfeng; Han, Lian; Lu, Rongguo; Hu, Yunxiao; Li, Zhuo; Liu, Yong

    2016-06-01

    We report a passively Q-switched Tm3+-doped fiber laser using a black phosphorus deposited micro-fiber (BPDMF) as a saturable absorption (SA) device for the first time. The BPDMF prepared by depositing black phosphorus (BP) on the micro-fiber waist with heat convention effect and optical tweezer effect has a measured modulation depth of 40.2% and a nonsaturable loss of 55.9%. By employing this device in an all-fiber ring cavity, a stable Q-switched pulse train at 1948 nm was achieved with a repetition rate from 12.5 to 28.1 kHz and a pulse width from 15.1 to 5.6 μs, respectively.

  16. Portable fiber-coupled diode-laser-based sensor for multiple trace gas detection

    NASA Technical Reports Server (NTRS)

    Lancaster, D. G.; Richter, D.; Tittel, F. K.

    1999-01-01

    Tunable narrowband mid-infrared radiation from 3.25 to 4.4 micrometers is generated by a compact fiber-coupled, difference-frequency-based spectroscopic source. A 20-mW external cavity diode laser (with a tuning range from 814 to 870 nm) and a 50-mW distributed-Bragg-reflector diode-laser-seeded ytterbium-doped fiber amplifier operating at 1083 nm are difference-frequency mixed in a multi-grating, temperature-controlled periodically poled LiNbO3 crystal. A conversion efficiency of 0.44 mW/(W2cm) (corresponding to a power of approximately equal to 3 microW at 3.3 micrometers) represents the highest conversion efficiency reported for a portable device. Performance characteristics of such a sensor and its application to spectroscopic detection of CO2, N2O, H2CO, HCl, NO2, and CH4 will be reported in this work.

  17. Portable fiber-coupled diode-laser-based sensor for multiple trace gas detection.

    PubMed

    Lancaster, D G; Richter, D; Tittel, F K

    1999-01-01

    Tunable narrowband mid-infrared radiation from 3.25 to 4.4 micrometers is generated by a compact fiber-coupled, difference-frequency-based spectroscopic source. A 20-mW external cavity diode laser (with a tuning range from 814 to 870 nm) and a 50-mW distributed-Bragg-reflector diode-laser-seeded ytterbium-doped fiber amplifier operating at 1083 nm are difference-frequency mixed in a multi-grating, temperature-controlled periodically poled LiNbO3 crystal. A conversion efficiency of 0.44 mW/(W2cm) (corresponding to a power of approximately equal to 3 microW at 3.3 micrometers) represents the highest conversion efficiency reported for a portable device. Performance characteristics of such a sensor and its application to spectroscopic detection of CO2, N2O, H2CO, HCl, NO2, and CH4 will be reported in this work. PMID:11542659

  18. Triwavelength synchronously mode-locked fiber laser based on few-layered black phosphorus

    NASA Astrophysics Data System (ADS)

    Zhao, Ruwei; Li, Jing; Zhang, Baitao; Li, Xiaowen; Su, Xiancui; Wang, Yiran; Lou, Fei; Zhang, Haikun; He, Jingliang

    2016-09-01

    A triwavelength synchronously mode-locked erbium-doped fiber laser with black phosphorus (BP) was demonstrated. The BP was proved to be not only an excellent saturable absorber (SA) but also a strong nonlinear material benefiting the stabilization of a multiwavelength fiber laser. The laser worked for a long time at three synchronous wavelengths of 1557.2, 1557.7, and 1558.2 nm. The autocorrelation trace of 9.41 ps pulses showed an interference beating of 0.06 THz, corresponding to a beating period of 16.37 ps. To the best of our knowledge, this is the first report on the usage of BP as an SA for building a multiwavelength synchronous mode-locked fiber laser.

  19. Tunable multiwavelength mode-locked Tm/Ho-doped fiber laser based on a nonlinear amplified loop mirror.

    PubMed

    Jin, Xiaoxi; Wang, Xiong; Wang, Xiaolin; Zhou, Pu

    2015-10-01

    We propose and demonstrate a tunable multiwavelength mode-locked Tm/Ho-doped fiber laser based on a nonlinear amplified loop mirror (NALM). Without using polarization-maintaining fiber, only passive fibers with low birefringence were inserted into the NALM to help overcome mode competition and realize mode-locking. The spacing between adjacent channels was measured to be ∼6  nm. By adjusting the polarization controllers (PCs) to an appropriate position, self-started mode-locking was achieved, which further overcame the mode competition in the fiber laser. A multiwavelength mode-locked fiber laser with at least three available channels were tunable in the widest range of 30 nm (from 1935 to 1965 nm) with a 3 dB channel bandwidth of ∼1.6  nm. This multiwavelength mode-locked fiber laser is quite stable with the maximum peak fluctuation within 0.47 dB in long-term observations.

  20. System simulation method for fiber-based homodyne multiple target interferometers using short coherence length laser sources

    NASA Astrophysics Data System (ADS)

    Fox, Maik; Beuth, Thorsten; Streck, Andreas; Stork, Wilhelm

    2015-09-01

    Homodyne laser interferometers for velocimetry are well-known optical systems used in many applications. While the detector power output signal of such a system, using a long coherence length laser and a single target, is easily modelled using the Doppler shift, scenarios with a short coherence length source, e.g. an unstabilized semiconductor laser, and multiple weak targets demand a more elaborated approach for simulation. Especially when using fiber components, the actual setup is an important factor for system performance as effects like return losses and multiple way propagation have to be taken into account. If the power received from the targets is in the same region as stray light created in the fiber setup, a complete system simulation becomes a necessity. In previous work, a phasor based signal simulation approach for interferometers based on short coherence length laser sources has been evaluated. To facilitate the use of the signal simulation, a fiber component ray tracer has since been developed that allows the creation of input files for the signal simulation environment. The software uses object oriented MATLAB code, simplifying the entry of different fiber setups and the extension of the ray tracer. Thus, a seamless way from a system description based on arbitrarily interconnected fiber components to a signal simulation for different target scenarios has been established. The ray tracer and signal simulation are being used for the evaluation of interferometer concepts incorporating delay lines to compensate for short coherence length.

  1. Fiber-Based Laser Transmitter at 1.57 Micrometers for Remote Sensing of Atmospheric Carbon Dioxide from Satellites

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Abshire, James B.; Stephen, Mark A.; Chen, Jeffrey R.; Wu, Stewart; Gonzalez, Brayler; Han, Lawrence; Numata, Kenji; Allan, Graham R.; Hasselbrack, William; Nicholson, Jeffrey W.; Yan, Man; Wisk, Patrick; DeSantolo, Anthony; DeSantolo, Anthony; Mangan, Brian; Puc, Gabe; Engin, Doruk; Mathason, Brian; Storm, Mark

    2015-01-01

    Over the past 20 years, NASA Goddard has successfully developed space-based lidar for remote sensing studies of the Earth and planets. The lidar in all missions to date have used diode pumped Nd:YAG laser transmitters. Recently we have been concentrating work on developing integrated path differential absorption (IPDA) lidar to measure greenhouse gases, with the goal of measurements from space. Due to the absorption spectrum of CO2 a fiber-based master oscillator power amplifier (MOPA) laser with a tunable seed source is an attractive laser choice. Fiber-based lasers offer a number of potential advantages for space, but since they are relatively new, challenges exist in developing them. In order to reduce risks for new missions using fiber-based lasers, we developed a 30- month plan to mature the technology of a candidate laser transmitter for space-based CO2 measurements to TRL-6. This work is also intended to reduce development time and costs and increase confidence in future mission success.

  2. Dark and bright pulses in a SOA-Based fiber ring laser

    NASA Astrophysics Data System (ADS)

    Mao, Yan; Tong, Xinglin; Wang, Zhiqiang; Zhan, Li; Hu, Pan; Guo, Qian

    2016-02-01

    We demonstrate the dark pulse emission in a semiconductor optical amplifier (SOA)-Based fiber ring laser with net abnormal dispersion. By means of the polarization-dependent property of SOA, the laser is mode-locked by using nonlinear polarization rotation (NPR) technique. Stable bright pulses and dark pulses are observed through changing the current of the SOA and altering the polarization states. The dependence of both the polarization states and the current of SOA on the formation of dark pulses in the cavity have been carefully investigated, revealing that the output average power of the measured dark pulse is far greater than that of the bright pulse under the same current. Moreover, the evolution process from bright pulse to dark pulse has been studied, showing the role of the extinction ratio of PCs in the transition process. The polarization dependent and bistability properties of SOA and the extinction ratio of PCs are dominant for the dark pulses generation, giving a further evidence of the generation of dark pulses in different laser cavity.

  3. Optical-fiber-based laser-induced breakdown spectroscopy for detection of early caries

    NASA Astrophysics Data System (ADS)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji

    2015-06-01

    A laser-induced breakdown spectroscopy (LIBS) system targeting for the in vivo analysis of tooth enamel is described. The system is planned to enable real-time analysis of teeth during laser dental treatment by utilizing a hollow optical fiber that transmits both Q-switched Nd:YAG laser light for LIBS and infrared Er:YAG laser light for tooth ablation. The sensitivity of caries detection was substantially improved by expanding the spectral region under analysis to ultraviolet (UV) light and by focusing on emission peaks of Zn in the UV region. Subsequently, early caries were distinguished from healthy teeth with accuracy rates above 80% in vitro.

  4. Multimodal fiber source for nonlinear microscopy based on a dissipative soliton laser.

    PubMed

    Lamb, Erin S; Wise, Frank W

    2015-09-01

    Recent developments in high energy femtosecond fiber lasers have enabled robust and lower-cost sources for multiphoton-fluorescence and harmonic-generation imaging. However, picosecond pulses are better suited for Raman scattering microscopy, so the ideal multimodal source for nonlinear microcopy needs to provide both durations. Here we present spectral compression of a high-power femtosecond fiber laser as a route to producing transform-limited picosecond pulses. These pulses pump a fiber optical parametric oscillator to yield a robust fiber source capable of providing the synchronized picosecond pulse trains needed for Raman scattering microscopy. Thus, this system can be used as a multimodal platform for nonlinear microscopy techniques. PMID:26417497

  5. Multimodal fiber source for nonlinear microscopy based on a dissipative soliton laser

    PubMed Central

    Lamb, Erin S.; Wise, Frank W.

    2015-01-01

    Recent developments in high energy femtosecond fiber lasers have enabled robust and lower-cost sources for multiphoton-fluorescence and harmonic-generation imaging. However, picosecond pulses are better suited for Raman scattering microscopy, so the ideal multimodal source for nonlinear microcopy needs to provide both durations. Here we present spectral compression of a high-power femtosecond fiber laser as a route to producing transform-limited picosecond pulses. These pulses pump a fiber optical parametric oscillator to yield a robust fiber source capable of providing the synchronized picosecond pulse trains needed for Raman scattering microscopy. Thus, this system can be used as a multimodal platform for nonlinear microscopy techniques. PMID:26417497

  6. A 160 W single-frequency laser based on an active tapered double-clad fiber amplifier

    NASA Astrophysics Data System (ADS)

    Trikshev, A. I.; Kurkov, A. S.; Tsvetkov, V. B.; Filatova, S. A.; Kertulla, J.; Filippov, V.; Chamorovskiy, Yu K.; Okhotnikov, O. G.

    2013-06-01

    We present a CW single-frequency laser at 1062 nm (linewidth <3 MHz) with 160 W of total output power based on a two stage fiber amplifier. A GTWave fiber is used for the first stage of the amplifier. A tapered double-clad fiber (T-DCF) is used for the second stage of the amplifier. The high output power is achieved due to the amplified spontaneous emission (ASE) filtering and increased stimulated Brillouin scattering (SBS) threshold inherent to the axially non-uniform geometry.

  7. Novel fiber lasers and applications

    NASA Astrophysics Data System (ADS)

    Zenteno, Luis A.; Walton, Donnell T.

    2003-07-01

    Glass fiber lasers were invented in the 60's by Elias Snitzer at Americal Optical, soon after the invention of the first solid-state glass laser. However, it was not until the 80's when these waveguide devices were deployed in industrial applications, driven largely by the technological success of the semiconductor laser diode, which provided practical and efficient pumps, and by the advent of low loss rare-earth-doped optical fiber.

  8. Visible fiber lasers excited by GaN laser diodes

    NASA Astrophysics Data System (ADS)

    Fujimoto, Yasushi; Nakanishi, Jun; Yamada, Tsuyoshi; Ishii, Osamu; Yamazaki, Masaaki

    2013-07-01

    This paper describes and discusses visible fiber lasers that are excited by GaN laser diodes. One of the attractive points of visible light is that the human eye is sensitive to it between 400 and 700 nm, and therefore we can see applications in display technology. Of course, many other applications exist. First, we briefly review previously developed visible lasers in the gas, liquid, and solid-state phases and describe the history of primary solid-state visible laser research by focusing on rare-earth doped fluoride media, including glasses and crystals, to clarify the differences and the merits of primary solid-state visible lasers. We also demonstrate over 1 W operation of a Pr:WPFG fiber laser due to high-power GaN laser diodes and low-loss optical fibers (0.1 dB/m) made by waterproof fluoride glasses. This new optical fiber glass is based on an AlF3 system fluoride glass, and its waterproof property is much better than the well known fluoride glass of ZBLAN. The configuration of primary visible fiber lasers promises highly efficient, cost-effective, and simple laser systems and will realize visible lasers with photon beam quality and quantity, such as high-power CW or tunable laser systems, compact ultraviolet lasers, and low-cost ultra-short pulse laser systems. We believe that primary visible fiber lasers, especially those excited by GaN laser diodes, will be effective tools for creating the next generation of research and light sources.

  9. High power incoherent beam combining of fiber lasers based on a 7 × 1 all-fiber signal combiner

    NASA Astrophysics Data System (ADS)

    Zhou, Xuanfeng; Chen, Zilun; Wang, Zefeng; Hou, Jing; Xu, Xiaojun

    2016-05-01

    We report an experiment of incoherent beam combining based on a 7×1 all-fiber signal combiner with output power up to 6.08 kW. Properties of transmission efficiency and beam quality are analyzed by beam propagation method. Based on the calculative results, a 7×1 all-fiber signal combiner is fabricated. The handle power capacity is tested with average transmission efficiency of 98.9% and beam quality of M2≈10.

  10. Fiber-Based Laser Speckle Imaging for the Detection of Pulsatile Flow

    PubMed Central

    Regan, Caitlin; Yang, Bruce Y.; Mayzel, Kent C.; Ramirez-San-Juan, Julio C.; Wilder-Smith, Petra; Choi, Bernard

    2015-01-01

    Background and Objective In endodontics, a major diagnostic challenge is the accurate assessment of pulp status. In this study, we designed and characterized a fiber-based laser speckle imaging system to study pulsatile blood flow in the tooth. Study Design/Materials and Methods To take transilluminated laser speckle images of the teeth, we built a custom fiber-based probe. To assess our ability to detect changes in pulsatile flow, we performed in vitro and preliminary in vivo tests on tissue-simulating phantoms and human teeth. We imaged flow of intralipid in a glass microchannel at simulated heart rates ranging from 40 beats/minute (bpm) to 120 bpm (0.67–2.00 Hz). We also collected in vivo data from the upper front incisors of healthy subjects. From the measured raw speckle data, we calculated temporal speckle contrast versus time. With frequency-domain analysis, we identified the frequency components of the contrast waveforms. Results With our approach, we observed in vitro the presence of pulsatile flow at different simulated heart rates. We characterized simulated heart rate with an accuracy of and >98%. In the in vivo proof-of-principle experiment, we measured heart rates of 69, 90, and 57 bpm, which agreed with measurements of subject heart rate taken with a wearable, commercial pulse oximeter. Conclusions We designed, built, and tested the performance of a dental imaging probe. Data from in vitro and in vivo tests strongly suggest that this probe can detect the presence of pulsatile flow. LSI may enable endodontists to noninvasively assess pulpal vitality via direct measurement of blood flow. PMID:26202900

  11. Yb fiber laser pumped mid-IR source based on difference frequency generation and its application to ammonia detection

    NASA Technical Reports Server (NTRS)

    Matsuoka, N.; Yamaguchi, S.; Nanri, K.; Fujioka, T.; Richter, D.; Tittel, F. K.

    2001-01-01

    A Yb fiber laser pumped cw narrow-linewidth tunable mid-IR source based on a difference frequency generation (DFG) in a periodically poled LiNbO3 (PPLN) crystal for trace gas detection was demonstrated. A high power Yb fiber laser and a distributed feedback (DFB) laser diode were used as DFG pump sources. This source generated mid-IR at 3 microns with a powers of 2.5 microW and a spectral linewidth of less than 30 MHz. A frequency tuning range of 300 GHz (10 cm-1) was obtained by varying the current and temperature of the DFB laser diode. A high-resolution NH3 absorption Doppler-broadened spectrum at 3295.4 cm-1 (3.0345 microns) was obtained at a cell pressure of 27 Pa from which a detection sensitivity of 24 ppm m was estimated.

  12. Yb fiber laser pumped mid-IR source based on difference frequency generation and its application to ammonia detection.

    PubMed

    Matsuoka, N; Yamaguchi, S; Nanri, K; Fujioka, T; Richter, D; Tittel, F K

    2001-02-01

    A Yb fiber laser pumped cw narrow-linewidth tunable mid-IR source based on a difference frequency generation (DFG) in a periodically poled LiNbO3 (PPLN) crystal for trace gas detection was demonstrated. A high power Yb fiber laser and a distributed feedback (DFB) laser diode were used as DFG pump sources. This source generated mid-IR at 3 microns with a powers of ~2.5 microW and a spectral linewidth of less than 30 MHz. A frequency tuning range of 300 GHz (10 cm-1) was obtained by varying the current and temperature of the DFB laser diode. A high-resolution NH3 absorption Doppler-broadened spectrum at 3295.4 cm-1 (3.0345 microns) was obtained at a cell pressure of 27 Pa from which a detection sensitivity of 24 ppm m was estimated. PMID:11676447

  13. Concept and design of an FBG emulator for a scanning laser-based fiber optic interrogator

    NASA Astrophysics Data System (ADS)

    Kuhenuri, Nader; Putzer, Philipp; Koch, Alexander W.; Obermaier, Johannes; Schweyer, Sebastian; Hurni, Andreas

    2014-06-01

    The Hybrid Sensor Bus is a space-borne temperature monitoring system for telecommunication satellites com­ bining electrical and fiber-optical Fiber Bragg Grating (FBG) sensors. Currently, there is no method available for testing the functionality and robustness of the system without setting up an actual sensor-network implying numerous FBG sensors in which each has to be heated/cooled individually. As a verification method of the mentioned system, FBG reflection based scanning laser interrogator, an FBG­ emulator is implemented to emulate the necessary FBG sensors. It is capable of immediate emulation of any given FBG spectrum, thus, any temperature. The concept provides advantages like emulating different kinds of FBGs with any peak shape, variable Bragg-wavelength λB, maximal-reflectivity τmax, spectral-width and degradation characteristics. Further, it facilitates an efficient evaluation of different interrogator peak-finding algorithms and the capability of emulating up to 10000 sample points per second is achieved. In the present paper, different concepts will be discussed and evaluated yielding to the implementation of a Variable Optical Attenuator (VOA) as the main actuator of the emulator. The actuator choice is further restricted since the emulator has to work with light in unknown polarization state. In order to implement a fast opto-ceramic VOA, issues like temperature dependencies, up to 200 V driving input and capacitive load have to be overcome. Furthermore, a self-calibration procedure mitigates problems like attenuation losses and long-term drift.

  14. Multiwavelength erbium fiber ring laser using Sagnac loop and Fabry-Perot laser diode

    NASA Astrophysics Data System (ADS)

    Yeh, C.-H.; Shih, F.-Y.; Chen, C.-T.; Lee, C.-N.; Chi, S.

    2008-03-01

    We propose and demonstrate experimentally a simply multiple-wavelength erbium compound ring fiber laser employing a Sagnac interferometer with erbium-doped fiber amplifier (EDFA) and Fabry-Perot laser diode (FP-LD). The proposed laser has the advantage of simply structure and easy fabrication, lower insertion loss and cost-effective. Based on the Sagnac fiber laser scheme, the proposed laser can lase eight wavelengths simultaneously. Moreover, the optical output stability of the ring laser has been also discussed.

  15. Laser induced twin-groove surface texturing based on optical fiber modulation

    NASA Astrophysics Data System (ADS)

    Liu, Dameng; Wang, Hui; Su, Kang; Tan, Qiaofeng; Bai, Benfeng; Shao, Tianmin

    2013-05-01

    A new and simple twin-groove texture method is carried out by using an optical fiber as a focus unit in a laser surface texturing process. A laser pulse produces a set of twin grooves, which has 1-2 μm width, much slimmer than the 3 μm width of the grooves etched at the fiber’s focus point. The length-width ratio of the ultra-long twin grooves is over 2000. Micro-textures of twin grooves and meshed textures were produced on Si and (Ti, Al, Si)N hard coating, whose characters were strongly affected by the light diffraction behind the fibers. Finite-element simulations show that the energy fields in the fiber etching system are following Fresnel diffraction rules, which modulate the input energy to be localized on the coating surface.

  16. Fiber-optic gas pressure sensing with a laser-heated silicon-based Fabry-Perot interferometer.

    PubMed

    Liu, Guigen; Han, Ming

    2015-06-01

    We report a novel fiber-optic sensor for measurement of static gas pressure based on the natural convection of a heated silicon pillar attached to a fiber tip functioning as a Fabry-Perot interferometer (FPI). A visible laser beam is guided by the fiber to efficiently heat the silicon pillar, while an infrared whitelight source, also guided by the fiber, is used to measure the temperature of the FPI, which is influenced both by the laser power and the pressure through natural convection. We theoretically and experimentally show that, by monitoring the fringe shift caused by the laser heating, air pressure sensing with little temperature cross-sensitivity can be achieved. The pressure sensitivity can be easily tuned by adjusting the heating laser power. In our experiment, the sensor performance within the temperature range from 20°C to 50°C and the pressure range from 0 to 1400 psi has been characterized, showing an average sensitivity of -0.52  pm/psi. Compared to the passive version of the sensor, the pressure sensitivity was ∼15 times larger, and the temperature cross-sensitivity was ∼100 times smaller. PMID:26030532

  17. Stable mode-locked fiber laser based on CVD fabricated graphene saturable absorber.

    PubMed

    Huang, Pi Ling; Lin, Shau-Ching; Yeh, Chao-Yung; Kuo, Hsin-Hui; Huang, Shr-Hau; Lin, Gong-Ru; Li, Lain-Jong; Su, Ching-Yuan; Cheng, Wood-Hi

    2012-01-30

    A stable mode-locked fiber laser (MLFL) employing multi-layer graphene as saturable absorber (SA) is presented. The multi-layer graphene were grown by chemical vapor deposition (CVD) on Ni close to A-A stacking. Linear absorbance spectrum of multi-layer graphene was observed without absorption peak from 400 to 2000 nm. Optical nonlinearities of different atomic-layers (7-, 11-, 14-, and 21- layers) graphene based SA are investigated and compared. The results found that the thicker 21-layer graphene based SA exhibited a smaller modulation depth (MD) value of 2.93% due to more available density of states in the band structure of multi-layer graphene and favored SA nonlinearity. A stable MLFL of 21-layer graphene based SA showed a pulsewidth of 432.47 fs, a bandwidth of 6.16 nm, and a time-bandwidth product (TBP) of 0.323 at fundamental soliton-like operation. This study demonstrates that the atomic-layer structure of graphene from CVD process may provide a reliable graphene based SA for stable soliton-like pulse formation of the MLFL.

  18. High-power ({gt}0.9 W cw) diffraction-limited semiconductor laser based on a fiber Bragg grating external cavity

    SciTech Connect

    Cornwell, D.M. , Jr.; Thomas, H.J.

    1997-02-01

    We have developed a high-power ({gt}0.9 W cw) diffraction-limited semiconductor laser based on a tapered semiconductor optical amplifier using a fiber Bragg grating in an external cavity configuration. Frequency-selective feedback from the fiber grating is injected into the amplifier via direct butt coupling through a single mode fiber, resulting in a spectrally stable and narrow ({lt}0.3 nm) high-power laser for solid-state laser pumping, laser remote sensing, and optical communications. {copyright} {ital 1997 American Institute of Physics.}

  19. Amplification of noise-like pulses generated from a graphene-based Tm-doped all-fiber laser.

    PubMed

    Sobon, Grzegorz; Sotor, Jaroslaw; Przewolka, Aleksandra; Pasternak, Iwona; Strupinski, Wlodek; Abramski, Krzysztof

    2016-09-01

    We report on the generation of noise-like pulse (NLP) trains in a Tm-doped fiber laser mode-locked by multilayer graphene saturable absorber. The spectral bandwidth obtained directly from the oscillator exceeds 60 nm, centered at 1950 nm, with 23.5 MHz repetition rate. The pulses were also amplified in a fully fiberized amplifier based on a double-cladding Tm-doped fiber. The system was capable of delivering 1.21 W of average power, which corresponds to 51.5 nJ energy stored in the noise-like bundle. We believe that the presented source might serve as a pump for supercontinuum generation in highly nonlinear fibers. PMID:27607642

  20. Experimental and numerical evaluation of freely spacing-tunable multiwavelength fiber laser based on two seeding light signals

    SciTech Connect

    Yuan, Yijun; Yao, Yong Guo, Bo; Yang, Yanfu; Tian, JiaJun; Yi, Miao

    2015-03-28

    A model of multiwavelength erbium-doped fiber laser (MEFL), which takes into account the impact of fiber attenuation on the four-wave-mixing (FWM), is proposed. Using this model, we numerically study the output characteristics of the MEFL based on FWM in a dispersion shift fiber with two seeding light signals (TSLS) and experimentally verify these characteristics. The numerical and experimental results show that the number of output channels can be increased with the increase of the erbium-doped fiber pump power. In addition, by decreasing the spacing of TSLS and increasing the power of TSLS, the number of output channels can be increased. However, when the power of TSLS exceeds a critical value, the number of output channels decreases. The results by numerical simulation are consistent with experimental observations from the MEFL.

  1. Microfiber-based few-layer black phosphorus saturable absorber for ultra-fast fiber laser.

    PubMed

    Luo, Zhi-Chao; Liu, Meng; Guo, Zhi-Nan; Jiang, Xiao-Fang; Luo, Ai-Ping; Zhao, Chu-Jun; Yu, Xue-Feng; Xu, Wen-Cheng; Zhang, Han

    2015-07-27

    Few-layer black phosphorus (BP), as the most alluring graphene analogue owing to its similar structure as graphene and thickness dependent direct band-gap, has now triggered a new wave of research on two-dimensional (2D) materials based photonics and optoelectronics. However, a major obstacle of practical applications for few-layer BPs comes from their instabilities of laser-induced optical damage. Herein, we demonstrate that, few-layer BPs, which was fabricated through the liquid exfoliation approach, can be developed as a new and practical saturable absorber (SA) by depositing few-layer BPs with microfiber. The saturable absorption property of few-layer BPs had been verified through an open-aperture z-scan measurement at the telecommunication band. The microfiber-based BP device had been found to show a saturable average power of ~4.5 mW and a modulation depth of 10.9%, which is further confirmed through a balanced twin detection measurement. By integrating this optical SA device into an erbium-doped fiber laser, it was found that it can deliver the mode-locked pulse with duration down to 940 fs with central wavelength tunable from 1532 nm to 1570 nm. The prevention of BP from oxidation through the "lateral interaction scheme" owing to this microfiber-based few-layer BP SA device might partially mitigate the optical damage problem of BP. Our results not only demonstrate that black phosphorus might be another promising SA material for ultrafast photonics, but also provide a practical solution to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as microfiber.

  2. Microfiber-based few-layer black phosphorus saturable absorber for ultra-fast fiber laser

    NASA Astrophysics Data System (ADS)

    Luo, Zhi-Chao; Liu, Meng; Guo, Zhi-Nan; Jiang, Xiao-Fang; Luo, Ai-Ping; Zhao, Chu-Jun; Yu, Xue-Feng; Xu, Wen-Cheng; Zhang, Han

    2015-07-01

    Few-layer black phosphorus (BP), as the most alluring graphene analogue owing to its similar structure as graphene and thickness dependent direct band-gap, has now triggered a new wave of research on two-dimensional (2D) materials based photonics and optoelectronics. However, a major obstacle of practical applications for few-layer BPs comes from their instabilities of laser-induced optical damage. Herein, we demonstrate that, few-layer BPs, fabricated through the liquid exfoliation approach, can be developed as a new and practical saturable absorber (SA) by depositing few-layer BPs with microfiber. The saturable absorption property of few-layer BPs had been verified through an open-aperture z-scan measurement at the telecommunication band and the microfiber-based BP device had been found to show a saturable average power of ~4.5 mW and a modulation depth of 10.9%, which is further confirmed through a balanced twin detection measurement. By further integrating this optical SA device into an erbium-doped fiber laser, it was found that it can deliver the mode-locked pulse with duration down to 940 fs with central wavelength tunable from 1532 nm to 1570 nm. The prevention of BP from oxidation through the 'lateral interaction scheme' owing to this microfiber-based few-layer BP SA device might partially mitigate the optical damage problem of BP. Our results not only demonstrate that black phosphorus might be another promising SA material for ultrafast photonics, but also provide a practical solution to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as microfiber.

  3. Thermally triggered fiber lasers based on secondary-type-In Bragg gratings.

    PubMed

    Feng, Fu-Rong; Ran, Yang; Liang, Yi-Zhi; Gao, Shuai; Feng, Yuan-Hua; Jin, Long; Guan, Bai-Ou

    2016-06-01

    The secondary-type-In grating formed in a small-core photosensitivity active fiber is discovered and investigated. Due to the different grating types, the transmission dip of a secondary grating structure chases and integrates with the type-In grating structure as the temperature increases, which strengthens the reflectivity of the grating. By use of these secondary-type-In gratings as Bragg reflectors, a thermally activated distributed Bragg reflector (DBR) fiber laser is proposed, which can be potentially used in high-temperature alarms and sensors. PMID:27244391

  4. Stimulated Raman hyperspectral imaging based on spectral filtering of broadband fiber laser pulses.

    PubMed

    Ozeki, Yasuyuki; Umemura, Wataru; Sumimura, Kazuhiko; Nishizawa, Norihiko; Fukui, Kiichi; Itoh, Kazuyoshi

    2012-02-01

    We demonstrate a technique of hyperspectral imaging in stimulated Raman scattering (SRS) microscopy using a tunable optical filter, whose transmission wavelength can be varied quickly by a galvanometer mirror. Experimentally, broadband Yb fiber laser pulses are synchronized with picosecond Ti:sapphire pulses, and then spectrally filtered out by the filter. After amplification by fiber amplifiers, we obtain narrowband pulses with a spectral width of <3.3 cm(-1) and a wavelength tunability of >225 cm(-1). By using these pulses, we accomplish SRS imaging of polymer beads with spectral information.

  5. Stimulated Raman hyperspectral imaging based on spectral filtering of broadband fiber laser pulses.

    PubMed

    Ozeki, Yasuyuki; Umemura, Wataru; Sumimura, Kazuhiko; Nishizawa, Norihiko; Fukui, Kiichi; Itoh, Kazuyoshi

    2012-02-01

    We demonstrate a technique of hyperspectral imaging in stimulated Raman scattering (SRS) microscopy using a tunable optical filter, whose transmission wavelength can be varied quickly by a galvanometer mirror. Experimentally, broadband Yb fiber laser pulses are synchronized with picosecond Ti:sapphire pulses, and then spectrally filtered out by the filter. After amplification by fiber amplifiers, we obtain narrowband pulses with a spectral width of <3.3 cm(-1) and a wavelength tunability of >225 cm(-1). By using these pulses, we accomplish SRS imaging of polymer beads with spectral information. PMID:22297376

  6. High power fiber MOPA based QCW laser delivering pulses with arbitrary duration on demand at high modulation bandwidth.

    PubMed

    Petkovšek, Rok; Novak, Vid; Agrež, Vid

    2015-12-28

    We report on a concept of a fiber MOPA based quasi-CW laser working at high modulation bandwidths up to 40 MHz capable of producing arbitrary pulse durations at arbitrary repetition rates. An output power of over 100 W was achieved and an on-off contrast of 25 dB. The laser features a dual-channel (dual-wavelength) seed source, a double stage YDF amplifier and a volume-Bragg-grating-based signal de-multiplexer. Minimization of transients was conducted through experiment and model analysis. PMID:26831982

  7. A multiwavelength Er-doped fiber laser using a nonlinear optical loop mirror and a twin-core fiber-based Mach-Zehnder interferometer

    NASA Astrophysics Data System (ADS)

    Yin, Guolu; Lou, Shuqin; Zou, Hui

    2013-04-01

    A multiwavelength Er-doped fiber (EDF) laser was proposed and experimentally demonstrated using a nonlinear optical loop mirror (NOLM) and a twin-core fiber-based Mach-Zehnder interferometer (TCF MZI). A total of 40 lasing wavelengths around the wavelength of 1560 nm with an average signal-to-noise ratio (SNR) of 28 dB and 30 lasing wavelengths around the wavelength of 1530 nm with an average SNR of 20 dB were achieved when the EDF length was 6 and 2 m, respectively. To the best of our knowledge, this is the first time that multiwavelength oscillations have been obtained in the wavelength range of 1530 nm by using a NOLM. The wavelength spacing is ˜0.19 nm which is determined by the TCF MZI. In addition, the effects of the pump power and the state of polarization on the performance of the multiwavelength EDF laser were investigated.

  8. Millimeter wave carrier generation based on a double-Brillouin-frequency spaced fiber laser.

    PubMed

    Shee, Y G; Al-Mansoori, M H; Yaakob, S; Man, A; Zamzuri, A K; Adikan, F R Mahamd; Mahdi, M A

    2012-06-01

    An all-optical generation of a millimeter wave carrier from a multiwavelength Brillouin-erbium fiber laser is presented. Four-channel output with spacing of about 21.5 GHz is generated from the fiber laser by controlling the gain in the cavity. A dual-wavelength signal with spacing correspondent to six orders of Brillouin frequency shift is obtained by suppressing the two channels at the middle. Heterodyning these signals at the high-speed photodetector produces a millimeter wave carrier at 64.17 GHz. Temperature dependence characteristic of Brillouin frequency shift realize the flexibility of generated millimeter wave frequency to be tuned at 6.6 MHz/ °C.

  9. A black phosphorus-based tunable Q-switched ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Salim, M. A. M.; Thambiratnam, K.; Norizan, S. F.; Harun, S. W.

    2016-09-01

    A compact, passively Q-switched fiber laser with a tunable output is demonstrated. The proposed system uses a short length ytterbium doped fiber to create a very stable and compact optical circuit that uses black phosphorus (BP) as a saturable absorber to generate the desired short pulses. A stable Q-switch pulse train is obtained, with an operational wavelength range from 1056.6–1083.3 nm. Concurrently, a maximum pulse energy and minimum pulse width as well as a repetition rate range of 7.1 nJ, 4 µs and 6.0–44.8 kHz respectively was obtained. The proposed system will be able to cater to a multitude of applications that require a compact yet robust and cost-effective pulse laser.

  10. Fiber laser-based scanning lidar for space rendezvous and docking.

    PubMed

    Luo, Yuan; He, Yan; Gao, Min; Zhou, Cuiyun; Zang, Huaguo; Lei, Linjun; Xie, Kedi; Yang, Yan; Shi, Wei; Hou, Xia; Chen, Weibiao

    2015-03-20

    Lidar systems have played an important role in space rendezvous and docking (RVD). A new type of scanning lidar is developed using a high-repetition-rate pulsed fiber laser and a position detector. It will be a candidate for autonomous space RVD between two spacecrafts. The lidar can search and track cooperative targets in a large region without artificial guidance. The lidar's operational range spans from 18 m to 20 km, and the relative angle between two aircrafts can be measured with high accuracy. A novel fiber laser with tunable pulse energy and repetition rate is developed to meet the wide dynamic detection range of the lidar. This paper presents the lidar system's composition, performance, and experimental results in detail.

  11. A black phosphorus-based tunable Q-switched ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Salim, M. A. M.; Thambiratnam, K.; Norizan, S. F.; Harun, S. W.

    2016-09-01

    A compact, passively Q-switched fiber laser with a tunable output is demonstrated. The proposed system uses a short length ytterbium doped fiber to create a very stable and compact optical circuit that uses black phosphorus (BP) as a saturable absorber to generate the desired short pulses. A stable Q-switch pulse train is obtained, with an operational wavelength range from 1056.6-1083.3 nm. Concurrently, a maximum pulse energy and minimum pulse width as well as a repetition rate range of 7.1 nJ, 4 µs and 6.0-44.8 kHz respectively was obtained. The proposed system will be able to cater to a multitude of applications that require a compact yet robust and cost-effective pulse laser.

  12. Fiber laser-based scanning lidar for space rendezvous and docking.

    PubMed

    Luo, Yuan; He, Yan; Gao, Min; Zhou, Cuiyun; Zang, Huaguo; Lei, Linjun; Xie, Kedi; Yang, Yan; Shi, Wei; Hou, Xia; Chen, Weibiao

    2015-03-20

    Lidar systems have played an important role in space rendezvous and docking (RVD). A new type of scanning lidar is developed using a high-repetition-rate pulsed fiber laser and a position detector. It will be a candidate for autonomous space RVD between two spacecrafts. The lidar can search and track cooperative targets in a large region without artificial guidance. The lidar's operational range spans from 18 m to 20 km, and the relative angle between two aircrafts can be measured with high accuracy. A novel fiber laser with tunable pulse energy and repetition rate is developed to meet the wide dynamic detection range of the lidar. This paper presents the lidar system's composition, performance, and experimental results in detail. PMID:25968536

  13. Surface-emitting fiber lasers

    NASA Astrophysics Data System (ADS)

    Shapira, Ofer; Kuriki, Ken; Orf, Nicholas D.; Abouraddy, Ayman F.; Benoit, Gilles; Viens, Jean F.; Rodriguez, Alejandro; Ibanescu, Mihai; Joannopoulos, John D.; Fink, Yoel; Brewster, Megan M.

    2006-05-01

    All fiber lasers to date emit radiation only along the fiber axis. Here a fiber that exhibits laser emission that is radially directed from its circumferential surface is demonstrated. A unique and controlled azimuthally anisotropic optical wave front results from the interplay between a cylindrical photonic bandgap fiber resonator, anisotropic organic dye gain, and a linearly polarized axial pump. Low threshold (86nJ) lasing at nine different wavelengths is demonstrated throughout the visible and near-infrared spectra. We also report the experimental realization of unprecedented layer thicknesses of 29.5 nm maintained throughout meter-long fibers. Such a device may have interesting medical applications ranging from photodynamic therapy to in vivo molecular imaging, as well as textile fabric displays.

  14. Thulium/holmium-doped fiber laser passively mode locked by black phosphorus nanoplatelets-based saturable absorber.

    PubMed

    Yu, Hao; Zheng, Xin; Yin, Ke; Cheng, Xiang'ai; Jiang, Tian

    2015-12-01

    By coupling black phosphorus (BP) nanoplatelets (NPs) with a fiber-taper evanescent light field, a saturable absorber (SA) based on the BP NPs has been successfully fabricated and used in a thulium/holmium-doped fiber laser as the mode locker. The SA had a modulation depth of ∼9.8% measured at 1.93 μm. A stable mode-locking operation at 1898 nm was achieved with a pulse width of 1.58 ps and a fundamental mode-lock repetition rate of 19.2 MHz. By increasing the pump intensity, phenomena of multi-pulsing operations, including harmonic mode-locked states and soliton bunches, were obtained in the experiment, showing that the BP NPs possess an ultrafast optical response time. This work suggests that the BP NPs-based SA is potentially useful for ultrashort, pulsed laser operations in the eye-safe region of 2 μm. PMID:26836690

  15. Femtosecond fiber laser additive manufacturing of tungsten

    NASA Astrophysics Data System (ADS)

    Bai, Shuang; Liu, Jian; Yang, Pei; Zhai, Meiyu; Huang, Huan; Yang, Lih-Mei

    2016-04-01

    Additive manufacturing (AM) is promising to produce complex shaped components, including metals and alloys, to meet requirements from different industries such as aerospace, defense and biomedicines. Current laser AM uses CW lasers and very few publications have been reported for using pulsed lasers (esp. ultrafast lasers). In this paper, additive manufacturing of Tungsten materials is investigated by using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. Fully dense Tungsten part with refined grain and increased hardness was obtained and compared with parts made with different pulse widths and CW laser. The results are evidenced that the fs laser based AM provides more dimensions to modify mechanical properties with controlled heating, rapid melting and cooling rates compared with a CW or long pulsed laser. This can greatly benefit to the make of complicated structures and materials that could not be achieved before.

  16. Widely tunable 11 GHz femtosecond fiber laser based on a nonmode-locked source [Widely tunable 11 GHz femtosecond fiber laser based on a non-modelocked source

    DOE PAGESBeta

    Prantil, Matthew A.; Cormier, Eric; Dawson, Jay W.; Gibson, David J.; Messerly, Michael J.; Barty, C. P. J.

    2013-08-19

    An 11 GHz fiber laser built on a modulated CW platform is described and characterized. This compact, vibrationinsensitive, fiber based system can be operated at wavelengths compatible with high energy fiber technology, is driven by an RF signal directly, and is tunable over a wide range of drive frequencies. The demonstration system when operated at 1040 nm is capable of 50 ns bursts of 575 micro-pulses produced at a macro-pulse rate of 83 kHz where the macro-pulse and micro-pulse energies are 1.8 μJ and 3.2 nJ respectively. Micro-pulse durations of 850 fs are demonstrated. Finally, we discuss extensions to shortermore » duration.« less

  17. Widely tunable 11 GHz femtosecond fiber laser based on a nonmode-locked source [Widely tunable 11 GHz femtosecond fiber laser based on a non-modelocked source

    SciTech Connect

    Prantil, Matthew A.; Cormier, Eric; Dawson, Jay W.; Gibson, David J.; Messerly, Michael J.; Barty, C. P. J.

    2013-08-19

    An 11 GHz fiber laser built on a modulated CW platform is described and characterized. This compact, vibrationinsensitive, fiber based system can be operated at wavelengths compatible with high energy fiber technology, is driven by an RF signal directly, and is tunable over a wide range of drive frequencies. The demonstration system when operated at 1040 nm is capable of 50 ns bursts of 575 micro-pulses produced at a macro-pulse rate of 83 kHz where the macro-pulse and micro-pulse energies are 1.8 μJ and 3.2 nJ respectively. Micro-pulse durations of 850 fs are demonstrated. Finally, we discuss extensions to shorter duration.

  18. Laser peening with fiber optic delivery

    DOEpatents

    Friedman, Herbert W.; Ault, Earl R.; Scheibner, Karl F.

    2004-11-16

    A system for processing a workpiece using a laser. The laser produces at least one laser pulse. A laser processing unit is used to process the workpiece using the at least one laser pulse. A fiber optic cable is used for transmitting the at least one laser pulse from the laser to the laser processing unit.

  19. High average power harmonic mode-locking of a Raman fiber laser based on nonlinear polarization evolution

    NASA Astrophysics Data System (ADS)

    Liu, J.; Zhao, C. J.; Gao, Y. X.; Fan, D. Y.

    2016-03-01

    We experimentally demonstrate the operation of a stable harmonically mode-locked Raman fiber laser based on the nonlinear polarization rotation technique. A maximum average output power of up to 235 mW is achieved at the repetition rate of 466.2 MHz, corresponding to the 1665th order harmonic mode-locking. The temporal width of the mode-locked pulse train is 450 ps. The experimental results should shed some light on the design of wavelength versatile ultrashort lasers with high repetition rate and average output power.

  20. Q-switched fiber laser based on transition metal dichalcogenides MoS(2), MoSe(2), WS(2), and WSe(2).

    PubMed

    Chen, Bohua; Zhang, Xiaoyan; Wu, Kan; Wang, Hao; Wang, Jun; Chen, Jianping

    2015-10-01

    In this paper, we report 4 different saturable absorbers based on 4 transition metal dichalcogenides (MoS(2), MoSe(2), WS(2), WSe(2)) and utilize them to Q-switch a ring-cavity fiber laser with identical cavity configuration. It is found that MoSe(2) exhibits highest modulation depth with similar preparation process among four saturable absorbers. Q-switching operation performance is compared from the aspects of RF spectrum, optical spectrum, repetition rate and pulse duration. WS(2) Q-switched fiber laser generates the most stable pulse trains compared to other 3 fiber lasers. These results demonstrate the feasibility of TMDs to Q-switch fiber laser effectively and provide a meaningful reference for further research in nonlinear fiber optics with these TMDs materials.

  1. 2-μm switchable dual-wavelength fiber laser with cascaded filter structure based on dual-channel Mach-Zehnder interferometer and spatial mode beating effect

    NASA Astrophysics Data System (ADS)

    Wang, Shun; Lu, Ping; Zhao, Shui; Liu, Deming; Yang, Wei; Zhang, Jiangshan

    2014-06-01

    We demonstrated a 2-μm switchable dual-wavelength fiber laser with cascaded filter structure based on dual-channel Mach-Zehnder interferometer and spatial mode beating effect. Few-mode fiber-embedded Sagnac ring configuration and a Mach-Zehnder interferometer are cascaded to form a multiwavelength filter for our previous 2-μm fiber laser. By adopting suitable fiber length and adjusting the polarization controller, we obtained a 2-μm dual-wavelength fiber laser with switchable wavelength interval. Experimental results revealed that the proposed laser shows higher quality and better stability compared with our previous work and it has potential applications in the fields of atmospheric propagation and microwave photonics.

  2. Compact Fiber Laser for 589nm Laser Guide Star Generation

    NASA Astrophysics Data System (ADS)

    Pennington, D.; Drobshoff, D.; Mitchell, S.; Brown, A.

    Laser guide stars are crucial to the broad use of astronomical adaptive optics, because they facilitate access to a large fraction of possible locations on the sky. Lasers tuned to the 589 nm atomic sodium resonance can create an artificial beacon at altitudes of 95-105 km, thus coming close to reproducing the light path of starlight. The deployment of multiconjugate adaptive optics on large aperture telescopes world-wide will require the use of three to nine sodium laser guide stars in order to achieve uniform correction over the aperture with a high Strehl value. Current estimates place the minimum required laser power at > 10 W per laser for a continuous wave source, though a pulsed format, nominally 6?s in length at ~ 16.7 kHz, is currently preferred as it would enable tracking the laser through the Na layer to mitigate spot elongation. The lasers also need to be compact, efficient, robust and turnkey. We are developing an all-fiber laser system for generating a 589 nm source for laser-guided adaptive optics. Fiber lasers are more compact and insensitive to alignment than their bulk laser counterparts, and the heat-dissipation characteristics of fibers, coupled with the high efficiencies demonstrated and excellent spatial mode characteristics, make them a preferred candidate for many high power applications. Our design is based on sum-frequency mixing an Er/Yb:doped fiber laser operating at 1583 nm with a 938 nm Nd:silica fiber laser in a periodically poled crystal to generate 589 nm. We have demonstrated 14 W at 1583 nm with an Er/Yb:doped fiber laser, based on a Koheras single frequency fiber oscillator amplified in an IPG Photonics fiber amplifier. The Nd:silica fiber laser is a somewhat more novel device, since the Nd3+ ions must operate on the resonance transition (i.e. 4F3/2-4I9/2), while suppressing ASE losses at the more conventional 1088 nm transition. Optimization of the ratio of the fiber core and cladding permits operation of the laser at room

  3. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Rob; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This slide presentation reviews the power frequencies for the doubled fiber laser. It includes information on the 780 nm laser, second harmonic generation in one crystal, cascading crystals, the tenability of laser systems, laser cooling, and directions for future work.

  4. Self-compression to 24 MW peak power in a fused silica solid-core fiber using a high-repetition rate thulium-based fiber laser system

    NASA Astrophysics Data System (ADS)

    Gebhardt, Martin; Gaida, Christian; Stutzki, Fabian; Hädrich, Steffen; Jauregui, Cesar; Limpert, Jens; Tünnermann, Andreas

    2016-03-01

    Complementing ultrafast thulium-doped fiber-laser systems with a subsequent nonlinear pulse compression stage can enable unique laser parameters at around 2 μm operation wavelength. Significant pulse shortening and peak power enhancement have been accomplished using a fused silica solid-core fiber. In this fiber a pulse peak power of 24 MW was achieved without catastrophic damage due to self-focusing. As compared to operation in the well-explored 1 μm wavelength region, increasing the emission wavelength to 2 μm has a twofold advantage for nonlinear compression in fused-silica solid-core fibers. This is because, on the one hand the self-focusing limit scales quadratically with the wavelength. On the other hand the dispersion properties of fused silica allow for self-compression of ultrashort pulses beyond 1.3 μm wavelength, which leads to strong spectral broadening from very compact setups without the need for external compression. Using this technique we have generated 1.1 μJpulses with 24 fs FWHM pulse duration (<4 optical cycles), 24 MW peak power and 24.6 W of average power. To the best of our knowledge, this is the highest average power obtained from any nonlinear compression experiment around 2 μm wavelength and the first demonstration of peak powers beyond 20 MW within a fused-silica solid-core fiber. This result emphasizes that thulium-doped fiber-based chirped-pulse amplification systems may outperform their ytterbiumdoped counterparts in terms of peak power due to the fourfold increase of the critical power of self-focusing.

  5. Experiment study of bio-tissue's temperature irradiated by laser based on optical fiber F-P sensor

    NASA Astrophysics Data System (ADS)

    Shan, Ning; Liu, Xia

    2014-08-01

    Laser has several advantages, such as strong anti-interference ability, quick speed, high power, agility and precision. It is widely applied in military and medicine fields. When laser acts on human body, biological tissue of human body will appear the phenomenon of ablation and carbonization and solidification. In order to effectively defend excess damage by laser, the thermal effect research of skin tissue should be carried out. Temperature is a key parameter in the processing between laser and bio-tissue. It is the mostly foundation using analyze size of thermal damage area and forecast thermal damage degree. In this paper, the low fineness optical fiber F-P sensing system for temperature measurement is designed and established. The real-time measurement system of temperature generated by laser irradiating bio-tissue is build based on the sensing system. The temperature distributing generated by laser in the bio-tissue is studied through experiment when the spot diameter of emission laser is difference with the same energy density and the energy density is difference with the same spot diameter of emission laser. The experimental results show that the sensing system can be used to the real-time temperature measurement of bio-tissue efficiency. It has small bulk. Its outer diameter is 250μm. And the hurt for bio-tissue is small. It has high respond speed. The respond time of temperature is less than 1s. These can be satisfied with practice demand. When the energy density of laser is same, the temperature rising in the same location is low along the spot diameter of emission laser increasing. When the spot diameter of emission laser is same, the temperature rising in the same location is increasing along with the energy density of laser increasing.

  6. Random Fabry-Perot resonator-based sub-kHz Brillouin fiber laser to improve spectral resolution in linewidth measurement.

    PubMed

    Xu, Yanping; Xiang, Dao; Ou, Zhonghua; Lu, Ping; Bao, Xiaoyi

    2015-05-01

    For the first time, we propose a novel Brillouin random fiber laser with a narrow linewidth of ∼860  Hz based on the bi-directionally pumped stimulated Brillouin scattering (SBS) in a 10-km-long optical fiber. A random fiber Fabry-Perot (FP) resonator is built up through the pump depletion effects of SBS at both ends of the fiber. A theoretical model is developed to reveal the physics behind the unique random FP resonator that enables narrow random lasing emission. The novel laser is successfully applied for linewidth characterization beyond 860 Hz of light source under test. PMID:25927748

  7. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    NASA Astrophysics Data System (ADS)

    Sotor, J.; Sobon, G.; Jagiello, J.; Lipinska, L.; Abramski, K. M.

    2015-04-01

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (Frep) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest Frep was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  8. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    SciTech Connect

    Sotor, J. Sobon, G.; Abramski, K. M.; Jagiello, J.; Lipinska, L.

    2015-04-07

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (F{sub rep}) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest F{sub rep} was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  9. Highly Efficient Tm-Doped Yttrium Aluminum Garnet Ceramic Laser Based on the Novel Fiber-Bulk Hybrid Configuration

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Shen, Deyuan; Huang, Haitao; Zhang, Xiaoqi; Tang, Dingyuan; Fan, Dianyuan

    2013-09-01

    A polycrystalline ceramic Tm3+-doped yttrium aluminum garnet (Tm:Y3Al5O12, Tm:YAG) laser based on the novel fiber-bulk hybrid configuration is demonstrated using a high-power and tunable Er,Yb co-doped fiber laser as the pump source. Lasing characteristics of a 4.0 at. % Tm:YAG ceramic are investigated at different pump wavelengths from 1617 to 1625 nm. With an output coupler of 10% transmission, a maximum output power of 3.9 W is obtained at 2013.2 nm under an 8.8 W incident pump power at the Tm:YAG absorption peak of 1620.4 nm, corresponding to a slope efficiency of 50.1% with respect to the incident pump power.

  10. Ytterbium fiber-based, 270 fs, 100 W chirped pulse amplification laser system with 1 MHz repetition rate

    NASA Astrophysics Data System (ADS)

    Zhao, Zhigang; Kobayashi, Yohei

    2016-01-01

    A 100 W Yb-doped, fiber-based, femtosecond, chirped pulse amplification laser system was developed with a repetition rate of 1 MHz, corresponding to a pulse energy of 100 µJ. Large-scale, fused-silica transmission gratings were used for both the pulse stretcher and compressor, with a compression throughput efficiency of ∼85%. A pulse duration of 270 fs was measured by second harmonic generation frequency-resolved optical gating (SHG-FROG). To the best of our knowledge, this is the shortest pulse duration ever achieved by a 100-W-level fiber chirped pulse amplification laser system at a repetition rate of few megahertz, without any special post-compression manipulation.

  11. Technology and applications of ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Lang, Marion; Hellerer, Thomas; Stuhler, Juergen

    2011-11-01

    We briefly review the key technology of modern fiber based femtosecond laser sources summarizing advantages and disadvantages of different mode-locking solutions. A description of possible extensions of a FemtoFiber-type modelocked Er-doped fiber laser oscillator (1560 nm) reveals the flexibility with respect to wavelength coverage (488 nm .. 2200 nm) and pulse duration (10 fs .. 10 ps). The resulting FemtoFiber family and its versions for instrument integration allow one to use these state-of-the-art light sources in many important applications, e.g. THz spectroscopy and microscopy. We show that, depending on the fiber laser model and the THz emitter, THz radiation can be produced with 4-10 THz bandwidth and detected with up to 60 dB signal-to-noise ratio (SNR). Electronically controlled optical scanning (ECOPS) - a unique method for fast, precise and comfortable sampling of the THz pulse or other pump-probe experiments - is described and recommended for efficient data acquisition. As examples for modern microscopy with ultrafast fiber lasers we present results of two-photon fluorescence, coherent microscopy techniques (SHG/THG/CARS) and fluorescence lifetime imaging (FLIM).

  12. Technology and applications of ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Lang, Marion; Hellerer, Thomas; Stuhler, Juergen

    2012-03-01

    We briefly review the key technology of modern fiber based femtosecond laser sources summarizing advantages and disadvantages of different mode-locking solutions. A description of possible extensions of a FemtoFiber-type modelocked Er-doped fiber laser oscillator (1560 nm) reveals the flexibility with respect to wavelength coverage (488 nm .. 2200 nm) and pulse duration (10 fs .. 10 ps). The resulting FemtoFiber family and its versions for instrument integration allow one to use these state-of-the-art light sources in many important applications, e.g. THz spectroscopy and microscopy. We show that, depending on the fiber laser model and the THz emitter, THz radiation can be produced with 4-10 THz bandwidth and detected with up to 60 dB signal-to-noise ratio (SNR). Electronically controlled optical scanning (ECOPS) - a unique method for fast, precise and comfortable sampling of the THz pulse or other pump-probe experiments - is described and recommended for efficient data acquisition. As examples for modern microscopy with ultrafast fiber lasers we present results of two-photon fluorescence, coherent microscopy techniques (SHG/THG/CARS) and fluorescence lifetime imaging (FLIM).

  13. 2 micron femtosecond fiber laser

    DOEpatents

    Liu, Jian; Wan, Peng; Yang, Lihmei

    2014-07-29

    Methods and systems for generating femtosecond fiber laser pulses are disclose, including generating a signal laser pulse from a seed laser oscillator; using a first amplifier stage comprising an input and an output, wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits an amplified and stretched signal laser pulse; using an amplifier chain comprising an input and an output, wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits a further amplified, stretched signal laser pulse. Other embodiments are described and claimed.

  14. Extra-broadband wavelength-tunable actively mode-locked short-cavity fiber ring laser using a bismuth-based highly nonlinear erbium-doped fiber

    NASA Astrophysics Data System (ADS)

    Fukuchi, Yutaka; Hirata, Kouji; Ikeoka, Hiroshi

    We demonstrate an ultra-wideband wavelength-tunable actively mode-locked short-cavity laser employing a 151-cm-long bismuth-based highly nonlinear erbium-doped fiber (Bi-HNL-EDF). A wavelength tuning range of 87 nm from 1533 nm to 1620 nm can be achieved because the Bi-HNL-EDF has an ultra-wide gain bandwidth. High nonlinearity of the Bi-HNL-EDF also collaborates with spectral filtering by an optical bandpass filter to suppress the supermode noise quite effectively. Total length of the fiber ring cavity is as short as 16 m. Thus, stable and clean 5.6-6.1 ps pulses with a repetition rate of 10 GHz are successfully obtained over the wavelength tuning range almost completely covering both the conventional wavelength band (1530-1565 nm) and the longer wavelength band (1565-1625 nm). The bismuth-based short-cavity fiber laser also shows good performance in the back-to-back bit-error-rate measurements, and maintains bit-error-free mode-locking operation throughout the entire wavelength tuning range.

  15. Femtosecond wavelength-tunable OPCPA system based on picosecond fiber laser seed and picosecond DPSS laser pump.

    PubMed

    Danilevičius, R; Zaukevičius, A; Budriūnas, R; Michailovas, A; Rusteika, N

    2016-07-25

    We present a compact and stable femtosecond wavelength-tunable optical parametric chirped pulse amplification (OPCPA) system. A novel OPCPA front-end was constructed using a multi-channel picosecond all-in-fiber source for seeding DPSS pump laser and white light supercontinuum generation. Broadband chirped pulses were parametrically amplified up to 1 mJ energy and compressed to less than 40 fs duration. Pulse wavelength tunability in the range from 680 nm to 930 nm was experimentally demonstrated. PMID:27464199

  16. Ultrafast fiber lasers for homeland security

    NASA Astrophysics Data System (ADS)

    Okhotnikov, O. G.

    2005-09-01

    Detecting weapons concealed underneath clothing, analyzing the contents of suspicious-looking envelopes, or even spotting the onset of cancer: these are just some of the exciting prospects that have been turning terahertz wave research into one of the most important topics in photonics. Most broadband pulsed THz sources are based on the excitation of different materials with ultrashort laser pulses. So far, generation of tunable narrow-band THz radiation has been demonstrated using ultrafast solid state lasers as a source of high-intensity optical pulses. The lack of a high-power, low-cost, portable room-temperature THz source is the most significant limitation of modern THz systems. Advances in fiber laser technology can be used to further the capabilities of the homeland security. Using semiconductor saturable absorber mirrors allows for reliable mode-locked operation with different values of cavity dispersion in a broad spectrum ranged from 900 to 1600 nm. Semiconductor saturable absorbers mirrors have been used successfully to initiate and to sustain mode-locking in a wide range of core-pumped fiber lasers. The main advantage of the semiconductor saturable absorber mirrors (SESAM) is the possibility to control important parameters such as absorption recovery time, saturation fluence and modulation depth through the device design, growth conditions and post-growth processing. The SESAM as a cavity mirror in the fiber laser results in compact size, environmentally stable and simple ultrashort pulse lasers that can cover wide wavelength range and generate optical pulses with durations from picoseconds to femtoseconds. Employing SESAM technology for mode-locking, the double-clad fiber laser promises superior pulse quality, high stability and pulse energy without need for power booster that eventually degrades the pulse quality due to nonlinear distortions in the amplifier fiber. We give an overview of recent achievements in ultrafast fiber lasers; discuss basic

  17. Hollow fiber based quantum cascade laser spectrometer for fast and sensitive drug identification

    NASA Astrophysics Data System (ADS)

    Herbst, J.; Scherer, B.; Ruf, A.; Erb, J.; Lambrecht, A.

    2012-01-01

    Sensitive and fast identification of drugs or drug precursors is important and necessary in scenarios like baggage or container check by customs or police. Fraunhofer IPM is developing a laser spectrometer using external cavity quantum cascade lasers (EC-QCL) to obtain mid-infrared (IR) absorption spectra in the wavelength range of the specific vibrational bands of amphetamines and their precursors. The commercial EC-QCL covers a tuning range of about 225 cm-1 within 1.4 s. The system could be used for different sample types like bulk samples or liquid solutions. A sampling unit evaporates the sample. Because of small sample amounts a 3 m long hollow fiber with an inner volume smaller than 1ml is used as gas cell and wave guide for the laser beam. This setup is suitable as a detector of a gas chromatograph instead of a standard detector (TCD or FID). The advantage is the selective identification of drugs by their IR spectra in addition to the retention time in the gas chromatographic column. In comparison to Fourier Transform IR systems the EC-QCL setup shows a good mechanical robustness and has the advantage of a point light source. Because of the good fiber incoupling performance of the EC-QCL it is possible to use hollow fibers. So, a good absorption signal is achieved because of the long optical path in the small cell volume without significant dilution. In first laboratory experiments a detection limit in the microgram range for pseudo ephedrine is achieved.

  18. Wedged Fibers Suppress Feedback of Laser Beam

    NASA Technical Reports Server (NTRS)

    Ladany, I.

    1986-01-01

    When injected laser is coupled into optical fiber, emission instabilities arise because of optical feedback losses from fiber into laser. Coupling efficiencies as high as 80 percent, however, obtained by shaping end of multimode fiber into obtuse-angled wedge. Because slanted sides eliminate back reflection, such wedged fiber achieves high coupling efficiency.

  19. Demodulation of fiber bragg grating sensors based on dynamic tuning of a multimode laser diode.

    PubMed

    Ferreira, L A; Diatzikis, E V; Santos, J L; Farahi, F

    1999-08-01

    Dither demodulation of fiber Bragg grating sensors illuminated with multimode light from laser diodes is theoretically and experimentally investigated. Quasi-static temperature and strain sensitivities of 0.09 degrees C/ radical Hz and 0.6 microepsilon/ radical Hz are obtained. We show that it is possible to measure small ac signals that lie outside the feedback loop bandwidth by using a synchronous detection referenced to twice the dither frequency. In this situation, dynamic strain sensitivity of 3.3 n(epsilon)/ radical Hz is achieved. PMID:18323963

  20. All fiber passively Q-switched laser

    DOEpatents

    Soh, Daniel B. S.; Bisson, Scott E

    2015-05-12

    Embodiments relate to an all fiber passively Q-switched laser. The laser includes a large core doped gain fiber having a first end. The large core doped gain fiber has a first core diameter. The laser includes a doped single mode fiber (saturable absorber) having a second core diameter that is smaller than the first core diameter. The laser includes a mode transformer positioned between a second end of the large core doped gain fiber and a first end of the single mode fiber. The mode transformer has a core diameter that transitions from the first core diameter to the second core diameter and filters out light modes not supported by the doped single mode fiber. The laser includes a laser cavity formed between a first reflector positioned adjacent the large core doped gain fiber and a second reflector positioned adjacent the doped single mode fiber.

  1. Ribbon Fiber Laser-Theory and Experiment

    SciTech Connect

    Beach, R J; Feit, M D; Brasure, L D; Payne, S A

    2002-05-10

    A scalable fiber laser approach is described based on phase-locking multiple gain cores in an antiguided structure. The waveguide is comprised of periodic sequences of gain- and no-gain-loaded segments having uniform index, within the cladding region. Initial experimental results are presented.

  2. Optical turbulence in fiber lasers.

    PubMed

    Wabnitz, Stefan

    2014-03-15

    We analyze the nonlinear stage of modulation instability in passively mode-locked fiber lasers leading to chaotic or noise-like emission. We present the phase-transition diagram among different regimes of chaotic emission in terms of the key cavity parameters: amplitude or phase turbulence, and spatio-temporal intermittency. PMID:24690788

  3. Multifunctional tunable multiwavelength erbium-doped fiber laser based on tunable comb filter and intensity-dependent loss modulation

    NASA Astrophysics Data System (ADS)

    Quan, Mingran; Li, Yuan; Tian, Jiajun; Yao, Yong

    2015-04-01

    A multiwavelength erbium-doped fiber laser based on tunable comb spectral filter and intensity-dependent loss modulation is proposed and experimentally demonstrated. The laser allows fine and multifunctional tunable operations of channel-spacing, peak-location, spectral-range, and wavelength-number. More specifically, channel-spacing switch from 0.4 nm to 0.2 nm and peak-location adjustment within half of free spectrum range are obtained via controlling the tunable comb filter. The wavelength-number and the spectral-range of the lasing lines can be accurately controlled by intensity-dependent loss modulation in the laser cavity, enabled by a power-symmetric nonlinear optical loop mirror. In addition, fine control over the wavelength-number at fixed spectral-range is realized by simply adjusting the pump power. More important, the tunable operation process for every type of specific parameter is individual, without influences for other output parameters. Such features of this fiber laser make it useful and convenient for the practical application.

  4. Tunable multi-wavelength erbium-doped fiber laser by cascading a standard Mach-Zehnder interferometer and a twin-core fiber-based filter

    NASA Astrophysics Data System (ADS)

    Yin, Guolu; Lou, Shuqin; Wang, Xin; Han, Bolin

    2013-12-01

    A tunable multi-wavelength erbium-doped fiber laser (MEDFL) based on a nonlinear optical loop mirror (NOLM) was proposed and experimentally demonstrated by cascading a standard Mach-Zehnder interferometer (MZI) and a twin-core fiber (TCF)-based filter. Due to the ‘blue shift’ of the transmission band of the TCF-based filter when the TCF was bent, a tunable lasing waveband was realized by moving the transmission band of the TCF-based filter to cover different channels provided by the standard MZI. Experimental results showed that the lasing waveband can be linearly tuned over a range of 24 nm from 1542 to 1566 nm with a channel spacing of 0.4 nm, a maximum lasing line amount of 19, and an optical signal to noise ratio (OSNR) of 39 dB. The stability of the laser spectra was verified with a wavelength drift of 0.04 nm and a power fluctuation of ±0.3 dB.

  5. The road to kilowatt fiber lasers

    NASA Astrophysics Data System (ADS)

    Carter, Adrian; Samson, Bryce N.; Tankala, Kanishka; Machewirth, David P.; Manyam, Upendra H.; Abramczyk, Jaroslaw; Farroni, Julia; Guertin, Douglas P.; Jacobson, Nils

    2004-06-01

    Although fiber amplifiers have been employed in communications systems for many years, until very recently the fiber laser was little more than a scientific curiosity. However the fiber laser format has a number of intrinsic advantages over lamp and diode pumped YAG lasers including size, reliability, wavelength selectivity, heat dissipation, wallplug efficiency and operational cost; and with kiloWatt output powers now possible fiber lasers are beginning to replace lamp and diode pumped YAG lasers in many industrial applications. In this paper we review the recent and ongoing advances in fiber design that have facilitated this revolution.

  6. Silicon photonics-based laser system for high performance fiber sensing

    NASA Astrophysics Data System (ADS)

    Ayotte, S.; Faucher, D.; Babin, A.; Costin, F.; Latrasse, C.; Poulin, M.; G.-Deschênes, É.; Pelletier, F.; Laliberté, M.

    2015-09-01

    We present a compact four-laser source based on low-noise, high-bandwidth Pound-Drever-Hall method and optical phase-locked loops for sensing narrow spectral features. Four semiconductor external cavity lasers in butterfly packages are mounted on a shared electronics control board and all other optical functions are integrated on a single silicon photonics chip. This high performance source is compact, automated, robust, operates over a wide temperature range and remains locked for days. A laser to resonance frequency noise of 0.25 Hz/rt-Hz is demonstrated.

  7. A custom-built two-photon microscope based on a mode-locked Yb3+ doped fiber laser

    NASA Astrophysics Data System (ADS)

    Kim, Dong Uk; Song, Hoseong; Song, Woosub, III; Kwon, Hyuk-Sang; Kim, Dug Yong

    2012-03-01

    Two-photon microscopy is a very attractive tool for the study of the three-dimensional (3D) and dynamic processes in cells and tissues. One of the feasible constructions of two-photon microscopy is the combination a confocal laser scanning microscope and a mode-locked Ti:sapphire laser. Even though this approach is the simplest and fastest implementation, this system is highly cost-intensive and considerably difficult in modification. Many researcher therefore decide to build a more cost-effective and flexible system with a self-developed software for operation and data acquisition. We present a custom-built two-photon microscope based on a mode-locked Yb3+ doped fiber laser and demonstrate two-photon fluorescence imaging of biological specimens. The mode-locked fiber laser at 1060 nm delivers 320 fs laser pulses at a frequency of 36 MHz up to average power of 80 mW. The excitation at 1060 nm can be more suitable in thick, turbid samples for 3D image construction as well as cell viability. The system can simply accomplish confocal and two-photon mode by an additional optical coupler that allows conventional laser source to transfer to the scanning head. The normal frame rate is 1 frames/s for 400 x 400 pixel images. The measured full width at half maximum resolutions were about 0.44 μm laterally and 1.34 μm axially. A multi-color stained convallaria, rat basophilic leukemia cells and a rat brain tissue were observed by two-photon fluorescence imaging in our system.

  8. Dual-wavelength single-longitudinal-mode erbium-doped fiber laser based on inverse-Gaussian apodized fiber Bragg grating and its application in microwave generation

    NASA Astrophysics Data System (ADS)

    Lin, Bo; Tjin, Swee Chuan; Zhang, Han; Tang, Dingyuan; Liang, Sheng; Hao, Jianzhong; Dong, Bo

    2011-03-01

    We propose a simple erbium-doped fiber ring laser. It consists of an inverse-Gaussian apodized fiber Bragg grating filter which has two ultra-narrow transmission bands, and an unpumped erbium-doped fiber as a saturable absorber. Stable dual-wavelength single-longitudinal-mode lasing with a wavelength separation of approximately 0.082 nm is achieved. A microwave signal at 10.502 GHz is demonstrated by beating the dual wavelengths at a photodetector.

  9. 469nm Fiber Laser Source

    SciTech Connect

    Drobshoff, A; Dawson, J W; Pennington, D M; Payne, S A; Beach, R

    2005-01-20

    We have demonstrated 466mW of 469nm light from a frequency doubled continuous wave fiber laser. The system consisted of a 938nm single frequency laser diode master oscillator, which was amplified in two stages to 5 Watts using cladding pumped Nd{sup 3+} fiber amplifiers and then frequency doubled in a single pass through periodically poled KTP. The 3cm long PPKTP crystal was made by Raicol Crystals Ltd. with a period of 5.9 {micro}m and had a phase match temperature of 47 degrees Centigrade. The beam was focused to a 1/e{sup 2} diameter in the crystal of 29 {micro}m. Overall conversion efficiency was 11% and the results agreed well with standard models. Our 938nm fiber amplifier design minimizes amplified spontaneous emission at 1088nm by employing an optimized core to cladding size ratio. This design allows the 3-level transition to operate at high inversion, thus making it competitive with the 1088nm 4-level transition. We have also carefully chosen the fiber coil diameter to help suppress propagation of wavelengths longer than 938 nm. At 2 Watts, the 938nm laser had an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >10:1).

  10. Silver halide fiber-based evanescent-wave liquid droplet sensing with room temperature mid-infrared quantum cascade lasers.

    PubMed

    Chen, J; Liu, Z; Gmachl, C; Sivco, D

    2005-08-01

    Quantum cascade lasers and unclad silver halide fibers were used to assemble mid-infrared fiber-optics evanescent-wave sensors suitable to measure the chemical composition of liquid droplets. The laser wavelengths were chosen to be in the regions which offer the largest absorption contrast between constituents inside the mixture droplets. A pseudo-Beer-Lambert law fits well with the experimental data. Using a 300microm diameter fiber with a 25 mm immersion length, the signal to noise ratios correspond to 1 vol.% for alpha-tocophenol in squalane and 2 vol.% for acetone in aqueous solution for laser wavenumbers of 1208 cm-1 and 1363 cm-1, respectively.

  11. 2-μm switchable, tunable and power-controllable dual-wavelength fiber laser based on parallel cavities using 3 × 3 coupler

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Lu, Ping; Wang, Shun; Liu, Deming; Zhang, Jiangshan

    2015-08-01

    We demonstrate a switchable, tunable and power-controllable dual-wavelength fiber laser in 2-μm region based on parallel cavities using a 3 × 3 coupler. The laser topology is based on the parallel connection of fiber Bragg gratings (FBGs) using 3 × 3 coupler which act as two individual cavities, so that the dual wavelengths are tunable and switchable by adjusting the center wavelengths of FBGs and the cavity losses, respectively. With suitable cavity losses and input pumping power, we can obtain a 2-μm switchable single- or dual-wavelength fiber laser. The proposed configuration has very good application prospects in the fields of atmospheric transmission, gas sensing, lidar and new wavelength-division-multiplexed fiber communication systems.

  12. Modern fiber laser beam welding of the newly-designed precipitation-strengthened nickel-base superalloys

    NASA Astrophysics Data System (ADS)

    Naffakh Moosavy, Homam; Aboutalebi, Mohammad-Reza; Seyedein, Seyed Hossein; Goodarzi, Massoud; Khodabakhshi, Meisam; Mapelli, Carlo; Barella, Silvia

    2014-04-01

    In the present research, the modern fiber laser beam welding of newly-designed precipitation-strengthened nickel-base superalloys using various welding parameters in constant heat input has been investigated. Five nickel-base superalloys with various Ti and Nb contents were designed and produced by Vacuum Induction Melting furnace. The fiber laser beam welding operations were performed in constant heat input (100 J mm-2) and different welding powers (400 and 1000 W) and velocities (40 and 100 mm s-1) using 6-axis anthropomorphic robot. The macro- and micro-structural features, weld defects, chemical composition and mechanical property of 3.2 mm weldments were assessed utilizing optical and scanning electron microscopes equipped with EDS analysis and microhardness tester. The results showed that welding with higher powers can create higher penetration-to-width ratios. The porosity formation was increased when the welding powers and velocities were increased. None of the welds displayed hot solidification and liquation cracks in 400 and 1000 W welding powers, but liquation phenomenon was observed in all the heat-affected zones. With increasing the Nb content of the superalloys the liquation length was increased. The changing of the welding power and velocity did not alter the hardness property of the welds. The hardness of welds decreased when the Ti content declined in the composition of superalloys. Finally, the 400 and 1000 W fiber laser powers with velocity of 40 and 100 m ms-1 have been offered for hot crack-free welding of the thin sheet of newly-designed precipitation-strengthened nickel-base superalloys.

  13. Visible upconversion lasers in praseodymium-ytterbium-doped fibers

    NASA Astrophysics Data System (ADS)

    Zellmer, H.; Riedel, P.; Tünnermann, A.

    We report on a ZBLAN-fiber-based praseodymium-ytterbium-doped upconversion fiber laser operating in the blue-green with diffraction-limited beam quality. cw output powers of more than 150 mW at 491 nm are achieved for several hours without degradation. The spectroscopic data of the active material and laser parameters including the amplitude noise are discussed.

  14. Latest developments of ultrafast fiber laser and its material applications

    NASA Astrophysics Data System (ADS)

    Cho, G. C.; Liu, B.; Shah, L.; Liu, Z.; Che, Y.; Xu, J.

    2009-02-01

    We address recent fiber-based femtosecond laser technology. Specifically, fiber-chirped pulse amplifier is discussed for the enabling the concept of real-world applications. We review recent selected material applications demonstrating advantages of ultrafast dynamics of highly repetitive pulse train in nanoparticle generation in pulsed-laser deposition and reliable Si wafer singulation.

  15. High-resolution spectrally-resolved fiber optic sensor interrogation system based on a standard DWDM laser module.

    PubMed

    Njegovec, Matej; Donlagic, Denis

    2010-11-01

    This paper presents a spectrally-resolved integration system suitable for the reading of Bragg grating, all-fiber Fabry-Perot, and similar spectrally-resolved fiber-optic sensors. This system is based on a standard telecommunication dense wavelength division multiplexing transmission module that contains a distributed feedback laser diode and a wavelength locker. Besides the transmission module, only a few additional opto-electronic components were needed to build an experimental interrogation system that demonstrated over a 2 nm wide wavelength interrogation range, and a 1 pm wavelength resolution. When the system was combined with a typical Bragg grating sensor, a strain resolution of 1 με and temperature resolution of 0.1 °C were demonstrated experimentally. The proposed interrogation system relies entirely on Telecordia standard compliant photonic components and can thus be straightforwardly qualified for use within the range of demanding applications.

  16. Separation of coexisting dynamical regimes in multistate intermittency based on wavelet spectrum energies in an erbium-doped fiber laser.

    PubMed

    Hramov, Alexander E; Koronovskii, Alexey A; Moskalenko, Olga I; Zhuravlev, Maksim O; Jaimes-Reategui, Rider; Pisarchik, Alexander N

    2016-05-01

    We propose a method for the detection and localization of different types of coexisting oscillatory regimes that alternate with each other leading to multistate intermittency. Our approach is based on consideration of wavelet spectrum energies. The proposed technique is tested in an erbium-doped fiber laser with four coexisting periodic orbits, where external noise induces intermittent switches between the coexisting states. Statistical characteristics of multistate intermittency, such as the mean duration of the phases for every oscillation type, are examined with the help of the developed method. We demonstrate strong advantages of the proposed technique over previously used amplitude methods. PMID:27300891

  17. Separation of coexisting dynamical regimes in multistate intermittency based on wavelet spectrum energies in an erbium-doped fiber laser.

    PubMed

    Hramov, Alexander E; Koronovskii, Alexey A; Moskalenko, Olga I; Zhuravlev, Maksim O; Jaimes-Reategui, Rider; Pisarchik, Alexander N

    2016-05-01

    We propose a method for the detection and localization of different types of coexisting oscillatory regimes that alternate with each other leading to multistate intermittency. Our approach is based on consideration of wavelet spectrum energies. The proposed technique is tested in an erbium-doped fiber laser with four coexisting periodic orbits, where external noise induces intermittent switches between the coexisting states. Statistical characteristics of multistate intermittency, such as the mean duration of the phases for every oscillation type, are examined with the help of the developed method. We demonstrate strong advantages of the proposed technique over previously used amplitude methods.

  18. Controllable Dual-Wavelength Fiber Laser

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Zhou, Jun; He, Bing; Liu, Hou-Kang; Liu, Chi; Wei, Yun-Rong; Dong, Jing-Xing; Lou, Qi-Hong

    2012-07-01

    We demonstrate a controllable dual-wavelength fiber laser which contains a master laser and a slave laser. The master laser is a kind of ring cavity laser which can be injected into by the slave laser. The output laser wavelength is controlled by injected power of the slave laser; both single- and dual-wavelength operation can be achieved. Under free running, the master laser generates 1064 nm laser output. Here the slave laser is a 1072 nm fiber laser. The 1064 nm and 1072 nm laser coexist in output spectrum for relatively low injected power. Dual-wavelength and power-ratio-tunable operation can be achieved. If the injected power of the slave laser is high enough, the 1064 nm laser is extinguished automatically and there is only 1072 nm laser output.

  19. 948 kHz repetition rate, picosecond pulse duration, all-PM 1.03 μm mode-locked fiber laser based on nonlinear polarization evolution

    NASA Astrophysics Data System (ADS)

    Boivinet, S.; Lecourt, J.-B.; Hernandez, Y.; Fotiadi, A.; Mégret, P.

    2014-05-01

    We present in this study a PM all-fiber laser oscillator passively mode-locked (ML) at 1.03 μm. The laser is based on Nonlinear Polarization Evolution (NPE) in polarization maintaining (PM) fibers. In order to obtain the mode-locking regime, a nonlinear reflective mirror including a fibered polarizer, a long fiber span and a fibered Faraday mirror (FM) is inserted in a Fabry-Perot laser cavity. In this work we explain the principles of operation of this original laser design that permits to generate ultrashort pulses at low repetition (lower that 1MHz) rate with a cavity length of 100 m of fiber. In this experiment, the measured pulse duration is about 6 ps. To our knowledge this is the first all-PM mode-locked laser based on the NPE with a cavity of 100m length fiber and a delivered pulse duration of few picosecondes. Furthermore, the different mode-locked regimes of the laser, i.e. multi-pulse, noise-like mode-locked and single pulse, are presented together with the ways of controlling the apparition of these regimes. When the single pulse mode-locking regime is achieved, the laser delivers linearly polarized pulses in a very stable way. Finally, this study includes numerical results which are obtained with the resolution of the NonLinear Schrodinger Equations (NLSE) with the Split-Step Fourier (SSF) algorithm. This modeling has led to the understanding of the different modes of operation of the laser. In particular, the influence of the peak power on the reflection of the nonlinear mirror and its operation are studied.

  20. Beam combinable, kilowatt, all-fiber amplifier based on phase-modulated laser gain competition.

    PubMed

    Naderi, Nader A; Flores, Angel; Anderson, Brian M; Dajani, Iyad

    2016-09-01

    We report power scaling results of a highly efficient narrow-linewidth monolithic Yb-doped fiber amplifier seeded with two signals, operating at 1038 and 1064 nm. With the appropriate seed power ratio applied, this technique was shown to suppress stimulated Brillouin scattering in conjunction with phase modulation, while generating the output power in predominantly the longer wavelength signal. Notably, the integration of laser gain competition with pseudo-random bit sequence phase modulation, set at a clock rate of 2.5 GHz and utilizing an optimized pattern to match the shortened effective nonlinear length, yielded 1 kW of output power. The beam quality was measured to be near the diffraction limit with no sign of transverse mode instability. Furthermore, the coherent beam combination performance of the amplifier provided a 90% combining efficiency with no indication of spectral broadening when compared to the single-tone case. Overall, the power scaling results represent a significant reduction in spectral linewidth compared to that of commercially available narrow-linewidth Yb-doped fiber amplifiers. PMID:27607948

  1. A fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot cavity

    NASA Astrophysics Data System (ADS)

    Liu, Guigen; Sheng, Qiwen; Resende Lisboa Piassetta, Geraldo; Hou, Weilin; Han, Ming

    2016-05-01

    A hot-wire fiber-optic water flow sensor based on laser-heated silicon Fabry-Pérot interferometer (FPI) has been proposed and demonstrated in this paper. The operation of the sensor is based on the convective heat loss to water from a heated silicon FPI attached to the cleaved enface of a piece of single-mode fiber. The flow-induced change in the temperature is demodulated by the spectral shifts of the reflection fringes. An analytical model based on the FPI theory and heat transfer analysis has been developed for performance analysis. Numerical simulations based on finite element analysis have been conducted. The analytical and numerical results agree with each other in predicting the behavior of the sensor. Experiments have also been carried to demonstrate the sensing principle and verify the theoretical analysis. Investigations suggest that the sensitivity at low flow rates are much larger than that at high flow rates and the sensitivity can be easily improved by increasing the heating laser power. Experimental results show that an average sensitivity of 52.4 nm/(m/s) for the flow speed range of 1.5 mm/s to 12 mm/s was obtained with a heating power of ~12 mW, suggesting a resolution of ~1 μm/s assuming a wavelength resolution of 0.05 pm.

  2. All-fiber normal-dispersion single-polarization passively mode-locked laser based on a 45°-tilted fiber grating.

    PubMed

    Liu, Xianglian; Wang, Hushan; Yan, Zhijun; Wang, Yishan; Zhao, Wei; Zhang, Wei; Zhang, Lin; Yang, Zhi; Hu, Xiaohong; Li, Xiaohui; Shen, Deyuan; Li, Cheng; Chen, Guangde

    2012-08-13

    An all-fiber normal-dispersion Yb-doped fiber laser with 45°-tilted fiber grating (TFG) is, to the best of our knowledge, experimentally demonstrated for the first time. Stable linearly-chirped pulses with the duration of 4 ps and the bandwidth of 9 nm can be directly generated from the laser cavity. By employing the 45° TFG with the polarization-dependent loss of 33 dB, output pulses with high polarization extinction ratio of 26 dB are implemented in the experiment. Our result shows that the 45° TFG can work effectively as a polarizer, which could be exploited to single-polarization all-fiber lasers.

  3. A LASER INTERFERENCE-BASED SURFACE TREATMENT OF AL AND CARBON FIBER POLYMER COMPOSITES FOR ENHANCED BONDING

    SciTech Connect

    Sabau, Adrian S; Warren, Charles David; ERDMAN III, DONALD L; Daniel, Claus; Skszek, Timothy; Caruso-Dailey, Mary M.

    2016-01-01

    Due to its increased use in the automotive and aerospace industries, joining of Carbon Fiber-reinforced Polymer matrix Composites (CFPC) to metals demands enhanced surface preparation and control of surface morphology prior to joining. In this study, surfaces of both composite and aluminum were prepared for joining using a new laser based technique, in which the laser interference power profile was created by splitting the beam and guiding those beams to the sample surface by overlapping each other with defined angles to each other. Results were presented for the overlap shear testing of single-lap joints made with Al 5182 and CFPC specimens whose surfaces prepared by (a) surface abrasion and solvent cleaning; and (b) laser-interference structured surfaces by rastering with a 4 mm laser beam at approximately 3.5 W power. CFPC specimens of T700S carbon fiber, Prepreg T70 epoxy, 4 or 5 ply thick, 0/90o plaques were used. Adhesive DP810 was used to bond Al and CFPC. The bondline was 0.25mm and the bond length was consistent among all joints produced. First, the effect of the laser speed on the joint performance was evaluated by laser-interference structure Al and CFPC surfaces with a beam angle of 3o and laser beam speeds of 3, 5, and 10 mm/s. For this sensitivity study, 3 joint specimens were used per each joint type. Based on the results for minimum, maximum, and mean values for the shear lap strength and maximum load for all the 9 joint types, two joint types were selected for further evaluations. Six additional joint specimens were prepared for these two joint types in order to obtain better statistics and the shear test data was presented for the range, mean, and standard deviation. The results for the single-lap shear tests obtained for six joint specimens, indicate that the shear lap strength, maximum load, and displacement at maximum load for those joints made with laser-interference structured surfaces were increased by approximately 14.8%, 16%, and 100

  4. Novel fiber optic tip designs and devices for laser surgery

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas Clifton

    Fiber optic delivery of laser energy has been used for years in various types of surgical procedures in the human body. Optical energy provides several benefits over electrical or mechanical surgery, including the ability to selectively target specific tissue types while preserving others. Specialty fiber optic tips have also been introduced to further customize delivery of laser energy to the tissue. Recent evolution in lasers and miniaturization has opened up opportunities for many novel surgical techniques. Currently, ophthalmic surgeons use relatively invasive mechanical tools to dissect retinal deposits which occur in proliferative diabetic retinopathy. By using the tight focusing properties of microspheres combined with the short optical penetration depth of the Erbium:YAG laser and mid-IR fiber delivery, a precise laser scalpel can be constructed as an alternative, less invasive and more precise approach to this surgery. Chains of microspheres may allow for a self limiting ablation depth of approximately 10 microm based on the defocusing of paraxial rays. The microsphere laser scalpel may also be integrated with other surgical instruments to reduce the total number of handpieces for the surgeon. In current clinical laser lithotripsy procedures, poor input coupling of the Holmium:YAG laser energy frequently damages and requires discarding of the optical fiber. However, recent stone ablation studies with the Thulium fiber laser have provided comparable results to the Ho:YAG laser. The improved spatial beam profile of the Thulium fiber laser can also be efficiently coupled into a fiber approximately one third the diameter and reduces the risk of damaging the fiber input. For this reason, the trunk optical fiber minus the distal fiber tip can be preserved between procedures. The distal fiber tip, which degrades during stone ablation, could be made detachable and disposable. A novel, low-profile, twist-locking, detachable distal fiber tip interface was designed

  5. Switchable, dual-wavelength passively mode-locked ultrafast fiber laser based on a single-wall carbon nanotube modelocker and intracavity loss tuning.

    PubMed

    Zhao, Xin; Zheng, Zheng; Liu, Lei; Liu, Ya; Jiang, Yaxing; Yang, Xin; Zhu, Jinsong

    2011-01-17

    We demonstrate a dual-wavelength passively mode-locked soliton fiber laser based on the single-wall carbon nanotube saturable absorber. By using a simple scheme of adjusting the intracavity loss, the gain profile of the erbium-doped fiber laser is effectively controlled. Besides operating at a single wavelength, the laser is able to simultaneously generate sub-picosecond pulses at both ~1532 and 1557 nm wavelength. The mode-locking wavelength can also be quickly switched from one wavelength to the other by changing the intracavity loss with a tunable attenuator.

  6. Multi-kW high-brightness fiber coupled diode laser based on two dimensional stacked tailored diode bars

    NASA Astrophysics Data System (ADS)

    Bayer, Andreas; Unger, Andreas; Köhler, Bernd; Küster, Matthias; Dürsch, Sascha; Kissel, Heiko; Irwin, David A.; Bodem, Christian; Plappert, Nora; Kersten, Maik; Biesenbach, Jens

    2016-03-01

    The demand for high brightness fiber coupled diode laser devices in the multi kW power region is mainly driven by industrial applications for materials processing, like brazing, cladding and metal welding, which require a beam quality better than 30 mm x mrad and power levels above 3kW. Reliability, modularity, and cost effectiveness are key factors for success in the market. We have developed a scalable and modular diode laser architecture that fulfills these requirements through use of a simple beam shaping concept based on two dimensional stacking of tailored diode bars mounted on specially designed, tap water cooled heat sinks. The base element of the concept is a tailored diode laser bar with an epitaxial and lateral structure designed such that the desired beam quality in slow-axis direction can be realized without using sophisticated beam shaping optics. The optical design concept is based on fast-axis collimator (FAC) and slow-axis collimator (SAC) lenses followed by only one additional focusing optic for efficient coupling into a 400 μm fiber with a numerical aperture (NA) of 0.12. To fulfill the requirements of scalability and modularity, four tailored bars are populated on a reduced size, tap water cooled heat sink. The diodes on these building blocks are collimated simply via FAC and SAC. The building blocks can be stacked vertically resulting in a two-dimensional diode stack, which enables a compact design of the laser source with minimum beam path length. For a single wavelength, up to eight of these building blocks, implying a total of 32 tailored bars, can be stacked into a submodule, polarization multiplexed, and coupled into a 400 μm, 0.12NA fiber. Scalability into the multi kW region is realized by wavelength combining of replaceable submodules in the spectral range from 900 - 1100 nm. We present results of a laser source based on this architecture with an output power of more than 4 kW and a beam quality of 25 mm x mrad.

  7. Raman soliton generation in microstructured tellurite fiber pumped by hybrid Erbium/Thulium fiber laser system

    NASA Astrophysics Data System (ADS)

    Anashkina, E. A.; Koptev, M. Y.; Muravyev, S. V.; Dorofeev, V. V.; Andrianov, A. V.; Kim, A. V.

    2016-08-01

    We demonstrate a fibre laser source generating ultrashort pulses tunable in the range 2-2.5 μm. The source is based on a hybrid Er/Tm fiber laser system and microstructured suspended-core tellurite fiber where Raman soliton shifting occurs. Nonlinear soliton dynamics is studied and possibility of tuning beyond 3 μm is shown.

  8. Polarization dependence of laser interaction with carbon fibers and CFRP.

    PubMed

    Freitag, Christian; Weber, Rudolf; Graf, Thomas

    2014-01-27

    A key factor for laser materials processing is the absorptivity of the material at the laser wavelength, which determines the fraction of the laser energy that is coupled into the material. Based on the Fresnel equations, a theoretical model is used to determine the absorptivity for carbon fiber fabrics and carbon fiber reinforced plastics (CFRP). The surface of each carbon fiber is considered as multiple layers of concentric cylinders of graphite. With this the optical properties of carbon fibers and their composites can be estimated from the well-known optical properties of graphite.

  9. Numerical simulation of passively mode-locked fiber laser based on semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Yang, Jingwen; Jia, Dongfang; Zhang, Zhongyuan; Chen, Jiong; Liu, Tonghui; Wang, Zhaoying; Yang, Tianxin

    2013-03-01

    Passively mode-locked fiber laser (MLFL) has been widely used in many applications, such as optical communication system, industrial production, information processing, laser weapons and medical equipment. And many efforts have been done for obtaining lasers with small size, simple structure and shorter pulses. In recent years, nonlinear polarization rotation (NPR) in semiconductor optical amplifier (SOA) has been studied and applied as a mode-locking mechanism. This kind of passively MLFL has faster operating speed and makes it easier to realize all-optical integration. In this paper, we had a thorough analysis of NPR effect in SOA. And we explained the principle of mode-locking by SOA and set up a numerical model for this mode-locking process. Besides we conducted a Matlab simulation of the mode-locking mechanism. We also analyzed results under different working conditions and several features of this mode-locking process are presented. Our simulation shows that: Firstly, initial pulse with the peak power exceeding certain threshold may be amplified and compressed, and stable mode-locking may be established. After about 25 round-trips, stable mode-locked pulse can be obtained which has peak power of 850mW and pulse-width of 780fs.Secondly, when the initial pulse-width is greater, narrowing process of pulse is sharper and it needs more round-trips to be stable. Lastly, the bias currents of SOA affect obviously the shape of mode-locked pulse and the mode-locked pulse with high peak power and narrow width can be obtained through adjusting reasonably the bias currents of SOA.

  10. Fiber laser coupled optical spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan; Joshi, Sachin; Reynolds, Adam

    2008-03-04

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  11. Mode-locked, 1.94-μm, all-fiberized laser using WS₂ based evanescent field interaction.

    PubMed

    Jung, Minwan; Lee, Junsu; Park, June; Koo, Joonhoi; Jhon, Young Min; Lee, Ju Han

    2015-07-27

    We demonstrate the use of an all-fiberized, mode-locked 1.94 μm laser with a saturable absorption device based on a tungsten disulfide (WS2)-deposited side-polished fiber. The WS2 particles were prepared via liquid phase exfoliation (LPE) without centrifugation. A series of measurements including Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) revealed that the prepared particles had thick nanostructures of more than 5 layers. The prepared saturable absorption device used the evanescent field interaction mechanism between the oscillating beam and WS2 particles and its modulation depth was measured to be ~10.9% at a wavelength of 1925 nm. Incorporating the WS2-based saturable absorption device into a thulium-holmium co-doped fiber ring cavity, stable mode-locked pulses with a temporal width of ~1.3 ps at a repetition rate of 34.8 MHz were readily obtained at a wavelength of 1941 nm. The results of this experiment confirm that WS2 can be used as an effective broadband saturable absorption material that is suitable to passively generate pulses at 2 μm wavelengths. PMID:26367658

  12. Note: Broadly tunable all-fiber ytterbium laser with 0.05 nm spectral width based on multimode interference filter

    SciTech Connect

    Mukhopadhyay, Pranab K. Gupta, Pradeep K.; Singh, Amarjeet; Sharma, Sunil K.; Bindra, Kushvinder S.; Oak, Shrikant M.

    2014-05-15

    A multimode interference filter with narrow transmission bandwidth and large self-imaging wavelength interval is constructed and implemented in an ytterbium doped fiber laser in all-fiber format for broad wavelength tunability as well as narrow spectral width of the output beam. The peak transmission wavelength of the multimode interference filter was tuned with the help of a standard in-fiber polarization controller. With this simple mechanism more than 30 nm (1038 nm–1070 nm) tuning range is demonstrated. The spectral width of the output beam from the laser was measured to be 0.05 nm.

  13. Ultrafast, high repetition rate, ultraviolet, fiber-laser-based source: application towards Yb+ fast quantum-logic.

    PubMed

    Hussain, Mahmood Irtiza; Petrasiunas, Matthew Joseph; Bentley, Christopher D B; Taylor, Richard L; Carvalho, André R R; Hope, Joseph J; Streed, Erik W; Lobino, Mirko; Kielpinski, David

    2016-07-25

    Trapped ions are one of the most promising approaches for the realization of a universal quantum computer. Faster quantum logic gates could dramatically improve the performance of trapped-ion quantum computers, and require the development of suitable high repetition rate pulsed lasers. Here we report on a robust frequency upconverted fiber laser based source, able to deliver 2.5 ps ultraviolet (UV) pulses at a stabilized repetition rate of 300.00000 MHz with an average power of 190 mW. The laser wavelength is resonant with the strong transition in Ytterbium (Yb+) at 369.53 nm and its repetition rate can be scaled up using high harmonic mode locking. We show that our source can produce arbitrary pulse patterns using a programmable pulse pattern generator and fast modulating components. Finally, simulations demonstrate that our laser is capable of performing resonant, temperature-insensitive, two-qubit quantum logic gates on trapped Yb+ ions faster than the trap period and with fidelity above 99%. PMID:27464118

  14. Crystal fibers for high power lasers

    NASA Astrophysics Data System (ADS)

    Kim, W.; Florea, C.; Gibson, D.; Peele, J.; Askins, C.; Shaw, B.; Bowman, S.; O'Connor, S.; Bayya, S.; Aggarwal, I.; Sanghera, J. S.

    2013-02-01

    In this paper, we present our recent progress in developing single crystal fibers for high power single frequency fiber lasers. The optical, spectral and morphological properties as well as the loss and gain measured from these crystal fibers drawn by Laser Heated Pedestal Growth (LHPG) system are also discussed. Results on application of various cladding materials on the crystal core and the methods of fiber end-face polishing are also presented.

  15. Fiber lasers and their applications [Invited].

    PubMed

    Shi, Wei; Fang, Qiang; Zhu, Xiushan; Norwood, R A; Peyghambarian, N

    2014-10-01

    Fiber lasers have seen progressive developments in terms of spectral coverage and linewidth, output power, pulse energy, and ultrashort pulse width since the first demonstration of a glass fiber laser in 1964. Their applications have extended into a variety of fields accordingly. In this paper, the milestones of glass fiber laser development are briefly reviewed and recent advances of high-power continuous wave, Q-switched, mode-locked, and single-frequency fiber lasers in the 1, 1.5, 2, and 3 μm regions and their applications in such areas as industry, medicine, research, defense, and security are addressed in detail.

  16. Dynamic control of the operation regimes of a mode-locked fiber laser based on intracavity polarizing fibers: experimental and theoretical validation.

    PubMed

    Villanueva, Guillermo E; Pérez-Millán, Pere

    2012-06-01

    An intracavity polarizing fiber is proposed to control the emission regime of a passively mode-locked fiber laser. Stable operation in self-starting high and low dispersion soliton mode-locking and 100 GHz multiwavelength regimes is demonstrated through numerical simulations and experimental validation. Mode-locking stability is ensured by a saturable absorber in the ring cavity. The effective selection of operation regime is dynamically carried out by controlling the intracavity polarization state.

  17. Fiber Laser Front Ends for High Energy, Short Pulse Lasers

    SciTech Connect

    Dawson, J; Messerly, M; Phan, H; Siders, C; Beach, R; Barty, C

    2007-06-21

    We are developing a fiber laser system for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal for these systems as they are highly reliable and enable long term stable operation.

  18. Laser and Optical Fiber Metrology in Romania

    SciTech Connect

    Sporea, Dan; Sporea, Adelina

    2008-04-15

    The Romanian government established in the last five years a National Program for the improvement of country's infrastructure of metrology. The set goal was to develop and accredit testing and calibration laboratories, as well as certification bodies, according to the ISO 17025:2005 norm. Our Institute benefited from this policy, and developed a laboratory for laser and optical fibers metrology in order to provide testing and calibration services for the certification of laser-based industrial, medical and communication products. The paper will present the laboratory accredited facilities and some of the results obtained in the evaluation of irradiation effects of optical and optoelectronic parts, tests run under the EU's Fusion Program.

  19. Laser and Optical Fiber Metrology in Romania

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Sporea, Adelina

    2008-04-01

    The Romanian government established in the last five years a National Program for the improvement of country's infrastructure of metrology. The set goal was to develop and accredit testing and calibration laboratories, as well as certification bodies, according to the ISO 17025:2005 norm. Our Institute benefited from this policy, and developed a laboratory for laser and optical fibers metrology in order to provide testing and calibration services for the certification of laser-based industrial, medical and communication products. The paper will present the laboratory accredited facilities and some of the results obtained in the evaluation of irradiation effects of optical and optoelectronic parts, tests run under the EU's Fusion Program.

  20. Making custom fiber lasers for use in an atomic physics experiment

    NASA Astrophysics Data System (ADS)

    Khademian, Ali; Cameron, Garnet; Nault, Kyla; Shiner, David

    2016-05-01

    Fiber lasers can be a reasonable choice for a laser source in atomic physics. Our particular applications involve the optical pumping and in some applications cooling of various transitions in atomic helium. Doped fiber with emission at the required wavelengths is necessary. Readily available fiber and approximate wavelength emission ranges include Yb (990 - 1150 nm), Er/Yb (1530 - 1625 nm) and Th (1900 -2100 nm). High efficiency conversion of pump photons into stable single frequency laser emission at the required wavelength is the function of the fiber laser. A simple fiber laser cavity uses a short (~ few mm) fiber grating high reflector mirror, a doped fiber section for the laser cavity, and a long (~ few cm) fiber grating output coupler. To ensure reliable single frequency operation, the laser cavity length should be within 2-3 times the output grating length. However the cavity length must be long enough for round trip gains to compensate for the output mirror transmission loss. Efficiency can be maximized by avoiding fiber splices in the fiber laser cavity. This requires that the gratings be written into the doped fiber directly. In our previous designs, back coupling of the fiber laser into the pump laser contributes to instability and sometimes caused catastrophic pump failure. Current designs use a fiber based wavelength splitter (WDM) to study and circumvent this problem. Data will be presented on the fiber lasers at 1083 nm. Work on a Thulium 2057 nm fiber laser will also be discussed. This work is supported by NSF Grant # 1404498.

  1. Tunable and switchable dual-wavelength single polarization narrow linewidth SLM erbium-doped fiber laser based on a PM-CMFBG filter.

    PubMed

    Yin, Bin; Feng, Suchun; Liu, Zhibo; Bai, Yunlong; Jian, Shuisheng

    2014-09-22

    A tunable and switchable dual-wavelength single polarization narrow linewidth single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser based on polarization-maintaining chirped moiré fiber Bragg grating (PM-CMFBG) filter is proposed and demonstrated. For the first time as we know, the CMFBG inscribed on the PM fiber is applied for the wavelength-tunable and-switchable dual-wavelength laser. The PM-CMFBG filter with ultra-narrow transmission band (0.1 pm) and a uniform polarization-maintaining fiber Bragg grating (PM-FBG) are used to select the laser longitudinal mode. The stable single polarization SLM operation is guaranteed by the PM-CMFBG filter and polarization controller. A tuning range of about 0.25 nm with about 0.075 nm step is achieved by stretching the uniform PM-FBG. Meanwhile, the linewidth of the fiber laser for each wavelength is approximate 6.5 and 7.1 kHz with a 20 dB linewidth, which indicates the laser linewidth is approximate 325 Hz and 355 Hz FWHM.

  2. High Average Power, High Energy Short Pulse Fiber Laser System

    SciTech Connect

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  3. OEM fiber laser rangefinder for long-distance measurement

    NASA Astrophysics Data System (ADS)

    Corman, Alexandre; Chiquet, Frédéric; Avisse, Thomas; Le Flohic, Marc

    2015-05-01

    SensUp designs and manufactures electro-optical systems based on laser technology, in particular from fiber lasers. Indeed, that kind of source enables us to get a significant peak power with huge repetition rates at the same time, thus combining some characteristics of the two main technologies on the telemetry field today: laser diodes and solid-state lasers. The OEM (Original Equipment Manufacturer) fiber Laser RangeFinder (LRF) set out below, aims to fit the SWaP (Size Weight and Power) requirements of military markets, and might turn out to be a real alternative to other technologies usually used in range finding systems.

  4. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers.

    PubMed

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-01-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers. PMID:27126900

  5. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers.

    PubMed

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-04-29

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers.

  6. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-04-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers.

  7. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers

    PubMed Central

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-01-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers. PMID:27126900

  8. Toward an ultra-broadband emission source based on the bismuth and erbium co-doped optical fiber and a single 830nm laser diode pump.

    PubMed

    Zhang, Jianzhong; Sathi, Zinat M; Luo, Yanhua; Canning, John; Peng, Gang-Ding

    2013-03-25

    We demonstrate a broadband optical emission from Bi/Er co-doped fiber and a single 830nm laser diode pump. The ultra-broadband mechanism is studied and discussed in details based on a combination of experimental measurements, including luminescence, differential luminescence and ESA, on fiber samples of different Bi and Er concentrations. The Er co-doping in Bi doped fiber is found to be effective for broadband emission, by enhancing not only luminescence at C and L bands but also that at O and shorter wavelength bands. The luminescence intensity between 1100 and 1570nm is over -45dBm/5nm in single mode fiber using a few meters of Bi/Er co-doped fiber and offers a modest ~40dB dynamic range and a broad bandwidth of ~470nm for an OSA based spectral measurement.

  9. Application of fiber laser for a Higgs factory

    SciTech Connect

    Chou, W.

    2014-06-04

    This paper proposes a medium size(~6km) circular Higgs factory based on a photon collider. The recent breakthrough in fiber laser technology by means of a coherent amplifier network makes such a collider feasible and probably also affordable.

  10. Long-distance fiber Bragg grating sensor system with a high optical signal-to-noise ratio based on a tunable fiber ring laser configuration.

    PubMed

    Rao, Yun-Jiang; Ran, Zeng-Ling; Chen, Rong-Rui

    2006-09-15

    A novel tunable fiber ring laser configuration with a combination of bidirectional Raman amplification and dual erbium-doped fiber (EDF) amplification is proposed for realizing high optical signal-to-noise ratio (SNR), long-distance, quasi-distributed fiber Bragg grating (FBG) sensing systems with large capacities and low cost. The hybrid Raman-EDF amplification configuration arranged in the ring laser can enhance the optical SNR of FBG sensor signals significantly owing to the good combination of the high gain of the erbium-doped fiber amplifier (EDFA) and the low noise of the Raman amplification. Such a sensing system can support a large number of FBG sensors because of the use of a tunable fiber Fabry-Perot filter located within the ring laser and spatial division multiplexing for expansion of sensor channels. Experimental results show that an excellent optical SNR of approximately 60 dB has been achieved for a 50 km transmission distance with a low Raman pump power of approximately 170 mW at a wavelength of 1455 nm and a low EDFA pump power of approximately 40 mW at a wavelength of 980 nm, which is the highest optical SNR achieved so far for a 50 km long FBG sensor system, to our knowledge. PMID:16936857

  11. 1.61 μm high-order passive harmonic mode locking in a fiber laser based on graphene saturable absorber.

    PubMed

    Meng, Yichang; Niang, Alioune; Guesmi, Khmaies; Salhi, Mohamed; Sanchez, Francois

    2014-12-01

    We demonstrate a passive mode-locked Er:Yb doped double-clad ring fiber laser based on graphene saturable absorber. By adjusting the polarization controller and minimizing the cavity loss, the laser can operate at hundreds of harmonics of the fundamental repetition frequency of the resonator with the central wavelength of 1.61 μm. Up to 683rd harmonic (which corresponds to 5.882 GHz) of the fundamental repetition frequency was achieved. PMID:25606922

  12. Silver halide fiber-based evanescent-wave liquid droplet sensing with room temperature mid-infrared quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Chen, J. Z.; Liu, Z.; Gmachl, C. F.; Sivco, D. L.

    2005-08-01

    Quantum cascade lasers and unclad silver halide fibers were used to assemble mid-infrared fiber-optics evanescent-wave sensors suitable to measure the chemical composition of liquid droplets. The laser wavelengths were chosen to be in the regions which offer the largest absorption contrast between constituents inside the mixture droplets. A pseudo-Beer-Lambert law fits well with the experimental data. Using a 300μm diameter fiber with a 25 mm immersion length, the signal to noise ratios correspond to 1 vol.% for α-tocophenol in squalane and 2 vol.% for acetone in aqueous solution for laser wavenumbers of 1208 cm-1 and 1363 cm-1, respectively.

  13. Nanosecond laser damage of optical multimode fibers

    NASA Astrophysics Data System (ADS)

    Mann, Guido; Krüger, Jörg

    2016-07-01

    For pulse laser materials processing often optical step index and gradient index multimode fibers with core diameters ranging from 100 to 600 μm are used. The design of a high power fiber transmission system must take into account limitations resulting from both surface and volume damage effects. Especially, breakdown at the fiber end faces and selffocusing in the fiber volume critically influence the fiber performance. At least operation charts are desirable to select the appropriate fiber type for given laser parameters. In industry-relevant studies the influence of fiber core diameter and end face preparation on laser-induced (surface) damage thresholds (LIDT) was investigated for frequently used all-silica fiber types (manufacturer LEONI). Experiments on preform material (initial fiber material) and compact specimens (models of the cladding and coating material) accompanied the tests performed in accordance with the relevant LIDT standards ISO 21254-1 and ISO 21254-2 for 1-on-1 and S-on-1 irradiation conditions, respectively. The relation beam diameter vs. LIDT was investigated for fused silica fibers. Additionally, laser-induced (bulk) damage thresholds of fused silica preform material F300 (manufacturer Heraeus) in dependence on external mechanical stress simulating fiber bending were measured. All experiments were performed with 10-ns laser pulses at 1064 and 532 nm wavelength with a Gaussian beam profile.

  14. Fiber optic applications for laser polarized targets

    SciTech Connect

    Cummings, W.J.; Kowalczyk, R.S.

    1997-10-01

    For the past two years, the laser polarized target group at Argonne has been used multi-mode fiber optic patch cords for a variety of applications. In this paper, the authors describe the design for transporting high power laser beams with optical fibers currently in use at IUCF.

  15. Fiber optic probes for laser light scattering: Ground based evaluation for micgrogravity flight experimentation. Integrated coherent imaging fiber optic systems for laser light scattering and other applications

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans Singh

    1994-01-01

    The research work presented in this report has established a new class of backscatter fiber optics probes for remote dynamic light scattering capability over a range of scattering angles from 94 degrees to 175 degrees. The fiber optic probes provide remote access to scattering systems, and can be utilized in either a noninvasive or invasive configuration. The fiber optics create an interference free data channel to inaccessible and harsh environments. Results from several studies of concentrated suspension, microemulsions, and protein systems are presented. The second part of the report describes the development of a new technology of wavefront processing within the optical fiber, that is, integrated fiber optics. Results have been very encouraging and the technology promises to have significant impact on the development of fiber optic sensors in a variety of fields ranging from environmental monitoring to optical recording, from biomedical sensing to photolithography.

  16. Microring embedded hollow polymer fiber laser

    SciTech Connect

    Linslal, C. L. Sebastian, S.; Mathew, S.; Radhakrishnan, P.; Nampoori, V. P. N.; Girijavallabhan, C. P.; Kailasnath, M.

    2015-03-30

    Strongly modulated laser emission has been observed from rhodamine B doped microring resonator embedded in a hollow polymer optical fiber by transverse optical pumping. The microring resonator is fabricated on the inner wall of a hollow polymer fiber. Highly sharp lasing lines, strong mode selection, and a collimated laser beam are observed from the fiber. Nearly single mode lasing with a side mode suppression ratio of up to 11.8 dB is obtained from the strongly modulated lasing spectrum. The microring embedded hollow polymer fiber laser has shown efficient lasing characteristics even at a propagation length of 1.5 m.

  17. Recent network sensing based on a combination of single mode fiber optics and semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Watanabe, Kazuhiro

    2007-05-01

    This paper describes the overview of the past decade's progress of network sensing supported by the use of single mode fiber optics in which glass fiber material itself exhibits sensing function, comparing with conventional FBG/BOTDR techniques, and newly developed hetero-core techniques. The hetero-core fiber optic sensor has been highlighted in terms of the fabrication process, the sensing mechanism and characteristics, and a road map toward commercialization to the variety of industrial applications.

  18. Characterization of fiber-laser-based sub-Doppler NICE-OHMS for quantitative trace gas detection.

    PubMed

    Foltynowicz, Aleksandra; Ma, Weiguang; Axner, Ove

    2008-09-15

    The potential of fiber-laser-based sub-Doppler noise-immune cavity-enhanced optical heterodyne molecular spectrometry for trace gas detection is scrutinized. The non-linear dependence of the on-resonance sub-Doppler dispersion signal on the intracavity pressure and power is investigated and the optimum conditions with respect to these are determined. The linearity of the signal strength with concentration is demonstrated and the dynamic range of the technique is discussed. Measurements were performed on C(2)H(2) at 1531 nm up to degrees of saturation of 100. The minimum detectable sub-Doppler optical phase shift was 5 x 10(-11) cm(-1) Hz(-1/2), corresponding to a partial pressure of C(2)H(2) of 1 x 10(-12) atm for an intracavity pressure of 20 mTorr, and a concentration of 10 ppb at 400 mTorr.

  19. Q-switched erbium-doped fiber ring laser with piezoelectric transducer-based PS-CFBG

    NASA Astrophysics Data System (ADS)

    Wu, Liangying; Pei, Li; Wang, Jianshuai; Li, Jing; Ning, Tigang; Liu, Shuo

    2016-09-01

    In this letter, a Q-switched erbium-doped fiber ring laser (EDFRL) with piezoelectric transducer (PZT)-based phase shift chirped fiber Bragg grating (PS-CFBG) has been proposed and demonstrated first. As known, the phase shift can be induced and wiped periodically by applying a modulation signal on the PZT. This makes it possible for the PZT-based PS-CFBG to be used in Q-switched EDFRL. To verify the performance of this Q-switched EDFRL system, some theoretical analyses and experiments have been performed. It is found that, when the PZT is modulated by a signal with frequencies of 1 and 2 kHz, pulse widths of the Q-switched pulse train are 19.8 μs and 15.6 μs, respectively. Besides, the corresponding pulse energies are 1.16 μJ (1 kHz) and 1.91 μJ (2 kHz) with a pump power of 90 mW.

  20. Diode pumped alkali vapor fiber laser

    DOEpatents

    Payne, Stephen A.; Beach, Raymond J.; Dawson, Jay W.; Krupke, William F.

    2007-10-23

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  1. Diode pumped alkali vapor fiber laser

    DOEpatents

    Payne, Stephen A.; Beach, Raymond J.; Dawson, Jay W.; Krupke, William F.

    2006-07-26

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  2. Hybrid distributed Raman amplification combining random fiber laser based 2nd-order and low-noise LD based 1st-order pumping.

    PubMed

    Jia, Xin-Hong; Rao, Yun-Jiang; Yuan, Cheng-Xu; Li, Jin; Yan, Xiao-Dong; Wang, Zi-Nan; Zhang, Wei-Li; Wu, Han; Zhu, Ye-Yu; Peng, Fei

    2013-10-21

    A configuration of hybrid distributed Raman amplification (H-DRA), that is formed by incorporating a random fiber laser (RFL) based 2nd-order pump and a low-noise laser-diode (LD) based 1st-order pump, is proposed in this paper. In comparison to conventional bi-directional 1st-order DRA, the effective noise figure (ENF) is found to be lower by amount of 0 to 4 dB due to the RFL-based 2nd-order pump, depending on the on-off gain, while the low-noise 1st-order Raman pump is used for compensating the worsened signal-to-noise ratio (SNR) in the vicinity towards the far end of the fiber and avoiding the potential nonlinear impact induced by excess injection of pump power and suppressing the pump-signal relative intensity noise (RIN) transfer. As a result, the gain distribution can be optimized along ultra-long fiber link, due to combination of the 2nd-order RFL and low-noise 1st-order pumping, making the transmission distance be extended significantly. We utilized such a configuration to achieve ultra-long-distance distributed sensing based on Brillouin optical time-domain analysis (BOTDA). A repeater-less sensing distance record of up to 154.4 km with 5 m spatial resolution and ~ ± 1.4 °C temperature uncertainty is successfully demonstrated.

  3. Tunable and switchable dual-wavelength mode-locked Tm3+-doped fiber laser based on a fiber taper.

    PubMed

    Wang, Yazhou; Li, Jianfeng; Zhai, Bo; Hu, Yunxiao; Mo, Kundong; Lu, Rongguo; Liu, Yong

    2016-07-11

    We demonstrate a self-starting dual-wavelength mode-locked fiber laser at a 2 μm spectral region by using a fiber taper in a Tm3+-doped ring fiber cavity. The fiber taper fabricated with a flame brushing technique was used as a periodic filter with a modulation depth of ~3.61 dB and a modulation period of ~7.3 nm, respectively. Diverse dual-wavelength regimes including continuous wave (CW)/multi-soliton, soliton/multi-soliton, and soliton/soliton regimes were obtained by adjusting pump power. Wavelength tuning for the dual-wavelength was also precisely controllable through stretching the fiber taper carefully. The tuning range was ~7 nm which was limited by the modulation period of the taper. By inserting a 10.0 m dispersion compensation fiber (DCF) into the fiber cavity, a stable dual-wavelength dissipative-soliton operation was obtained at 2 μm spectral region for the first time. PMID:27410806

  4. Tunable and switchable dual-wavelength mode-locked Tm3+-doped fiber laser based on a fiber taper.

    PubMed

    Wang, Yazhou; Li, Jianfeng; Zhai, Bo; Hu, Yunxiao; Mo, Kundong; Lu, Rongguo; Liu, Yong

    2016-07-11

    We demonstrate a self-starting dual-wavelength mode-locked fiber laser at a 2 μm spectral region by using a fiber taper in a Tm3+-doped ring fiber cavity. The fiber taper fabricated with a flame brushing technique was used as a periodic filter with a modulation depth of ~3.61 dB and a modulation period of ~7.3 nm, respectively. Diverse dual-wavelength regimes including continuous wave (CW)/multi-soliton, soliton/multi-soliton, and soliton/soliton regimes were obtained by adjusting pump power. Wavelength tuning for the dual-wavelength was also precisely controllable through stretching the fiber taper carefully. The tuning range was ~7 nm which was limited by the modulation period of the taper. By inserting a 10.0 m dispersion compensation fiber (DCF) into the fiber cavity, a stable dual-wavelength dissipative-soliton operation was obtained at 2 μm spectral region for the first time.

  5. Active fiber-based retroreflector providing phase-retracing anti-parallel laser beams for precision spectroscopy.

    PubMed

    Beyer, A; Maisenbacher, L; Matveev, A; Pohl, R; Khabarova, K; Chang, Y; Grinin, A; Lamour, T; Shi, T; Yost, D C; Udem, Th; Hänsch, T W; Kolachevsky, N

    2016-07-25

    We present an active fiber-based retroreflector providing high quality phase-retracing anti-parallel Gaussian laser beams for precision spectroscopy of Doppler sensitive transitions. Our design is well-suited for a number of applications where implementing optical cavities is technically challenging and corner cubes fail to match the demanded requirements, most importantly retracing wavefronts and preservation of the laser polarization. To illustrate the performance of the system, we use it for spectroscopy of the 2S-4P transition in atomic hydrogen and demonstrate an average suppression of the first order Doppler shift to 4 parts in 106 of the full collinear shift. This high degree of cancellation combined with our cryogenic source of hydrogen atoms in the metastable 2S state is sufficient to enable determinations of the Rydberg constant and the proton charge radius with competitive uncertainties. Advantages over the usual Doppler cancellation based on corner cube type retroreflectors are discussed as well as an alternative method using a high finesse cavity. PMID:27464193

  6. Simultaneous measurements of vibration, temperature, and humidity using a SOA-based fiber Bragg grating laser

    NASA Astrophysics Data System (ADS)

    Wang, Lutang; Fang, Nian; Ding, Fuxin; Huang, Zhaoming

    2010-12-01

    A novel SOA-based, dual-wavelength, FBG laser sensor system for simultaneously measuring vibration, temperature and humidity is demonstrated. The sensor interrogations are completed with a wavelength matching method by adjusting temperatures of two TECs to control wavelengths of two reference FBGs matching with those of two sensor FBGs. Two corresponding TEC control signals are used as detection outputs for temperature and humidity measurements. Some experimental results on simultaneous measurements of vibration, temperature of the sensor system with a FBG vibration/temperature senor and a 10-layer polyimide coating FBG humidity sensor are presented. The fundamental system performances in respects of the frequency response of system in vibration measurements and the tracing of the Bragg wavelength of sensor FBG through a TEC temperature control method were also demonstrated. The experimental results verified that the proposed FBG laser sensor system has a desired detection performance. This sensor system can be used in many industrial measurement fields, particularly in the electrical power industry for condition monitoring of power generators as well as high-voltage power transformers.

  7. Narrow line-width single-longitudinal-mode fiber laser using silicon-on-insulator based micro-ring-resonator

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Hsu, Yung; Hsu, Chin-Wei; Yang, Ling-Gang; Chow, Chi-Wai; Yeh, Chien-Hung; Lai, Yin-Chieh; Tsang, Hon-Ki

    2016-02-01

    In this work, we propose and demonstrate a stable single-longitudinal-mode (SLM) fiber laser with narrow line-width by using an integrated silicon-on-insulator micro-ring resonator (SOI MRR) and two subsidiary fiber rings for the first time, to the best of our knowledge. The laser is tunable over the wavelength range from 1546 to 1570 nm, with only step tuning of 2 nm steps. A maximum 49 dB side mode suppression ratio (SMSR) can be achieved. The compact SOI MRR provides a large free-spectral-range (FSR), while the subsidiary rings provide Vernier effect producing a single lasing mode. The FSR of the SOI MRR can be very large and controllable (since it is easy to fabricate small SOI MRR when compared with making small fiber-rings) using the complementary-metal-oxide-semiconductor (CMOS) compactable SOI fabrication processes. In our proposed laser, the measured single sideband (SSB) spectrum shows that the densely spaced longitudinal modes can be significantly suppressed to achieve SLM. The laser linewidth is only 3.5 kHz measured by using the self-heterodyne method. 30 min stability evaluation in terms of lasing wavelength and optical power is performed; showing the optical wavelength and power are both very stable, with fluctuations of only 0.02 nm and 0.8 dB, respectively.

  8. High-brightness fiber-coupled diode laser module

    NASA Astrophysics Data System (ADS)

    Dorsch, Friedhelm; Hennig, Petra; Nickel, Michael

    1998-05-01

    Based on a pair of step-mirrors for beam rearranging we coupled the emission of three high-power diode laser arrays into an optical fiber of 800 micrometer diameter. We compressed the fast axis collimated beams of three diode lasers in respect to their fast axes by means of a step prism and symmetrized the beam parameter product by reordering the radiation which is focused into a fiber then. By simple optimization a coupling efficiency of 70% can be obtained.

  9. Simplified method for numerical modeling of fiber lasers.

    PubMed

    Shtyrina, O V; Yarutkina, I A; Fedoruk, M P

    2014-12-29

    A simplified numerical approach to modeling of dissipative dispersion-managed fiber lasers is examined. We present a new numerical iteration algorithm for finding the periodic solutions of the system of nonlinear ordinary differential equations describing the intra-cavity dynamics of the dissipative soliton characteristics in dispersion-managed fiber lasers. We demonstrate that results obtained using simplified model are in good agreement with full numerical modeling based on the corresponding partial differential equations.

  10. Self-tuning fiber lasers

    NASA Astrophysics Data System (ADS)

    Brunton, Steven L.; Kutz, J. N.; Fu, Xing

    2016-03-01

    Advanced methods in data science are driving the characterization and control of nonlinear dynamical systems in optics. In this work, we investigate the use of machine learning, sparsity methods and adaptive control to develop a self-tuning fiber laser, which automatically learns and adapts to maintain high-energy ultrashort pulses. In particular, a two-stage procedure is introduced consisting of a machine learning algorithm to recognize different dynamical regimes with distinct behavior, followed by an adaptive control algorithm to reject disturbances and track optimal solutions despite stochastically varying system parameters. The machine learning algorithm, called sparse representation for classification, comes from machine vision and is typically used for image recognition. The adaptive control algorithm is extremum-seeking control, which has been applied to a wide range of systems in engineering; extremum-seeking is beneficial because of rigorous stability guarantees and ease of implementation.

  11. High power, high efficiency diode pumped Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Glick, Yaakov; Fromzel, Viktor; Zhang, Jun; Dahan, Asaf; Ter-Gabrielyan, Nikolay; Pattnaik, Radha K.; Dubinskii, Mark

    2016-06-01

    We demonstrate a high power high efficiency Raman fiber laser pumped directly by a laser diode module at 976 nm. 80 Watts of CW power were obtained at a wavelength of 1020 nm with an optical-to-optical efficiency of 53%. When working quasi-CW, at a duty cycle of 30%, 85 W of peak power was produced with an efficiency of 60%. A commercial graded-index (GRIN) core fiber acts as the Raman fiber in a power oscillator configuration, which includes spectral selection to prevent generation of the 2nd Stokes. In addition, significant brightness enhancement of the pump beam is attained due to the Raman gain distribution profile in the GRIN fiber. To the best of our knowledge, this is the highest power Raman fiber laser directly pumped by laser diodes, which also exhibits a record efficiency for such a laser. In addition, it is the highest power Raman fiber laser (regardless of pumping source) demonstrated based on a GRIN fiber.

  12. Laser transmission welding of long glass fiber reinforced thermoplastics

    NASA Astrophysics Data System (ADS)

    van der Straeten, Kira; Engelmann, Christoph; Olowinsky, Alexander; Gillner, Arnold

    2015-03-01

    Joining fiber reinforced polymers is an important topic for lightweight construction. Since classical laser transmission welding techniques for polymers have been studied and established in industry for many years joint-strengths within the range of the base material can be achieved. Until now these processes are only used for unfilled and short glass fiber-reinforced thermoplastics using laser absorbing and laser transparent matrices. This knowledge is now transferred to joining long glass fiber reinforced PA6 with high fiber contents without any adhesive additives. As the polymer matrix and glass fibers increase the scattering of the laser beam inside the material, their optical properties, changing with material thickness and fiber content, influence the welding process and require high power lasers. In this article the influence of these material properties (fiber content, material thickness) and the welding parameters like joining speed, laser power and clamping pressure are researched and discussed in detail. The process is also investigated regarding its limitations. Additionally the gap bridging ability of the process is shown in relation to material properties and joining speed.

  13. A high efficiency architecture for cascaded Raman fiber lasers.

    PubMed

    Supradeepa, V R; Nichsolson, Jeffrey W; Headley, Clifford E; Yan, Man F; Palsdottir, Bera; Jakobsen, Dan

    2013-03-25

    We demonstrate a new high efficiency architecture for cascaded Raman fiber lasers based on a single pass cascaded amplifier configuration. Conversion is seeded at all intermediate Stokes wavelengths using a multi-wavelength seed source. A lower power Raman laser based on the conventional cascaded Raman resonator architecture provides a convenient seed source providing all the necessary wavelengths simultaneously. In this work we demonstrate a 1480nm laser pumped by an 1117nm Yb-doped fiber laser with maximum output power of 204W and conversion efficiency of 65% (quantum-limited efficiency is ~75%). We believe both the output power and conversion efficiency (relative to quantum-limited efficiency) are the highest reported for cascaded Raman fiber lasers.

  14. Switchable and spacing-tunable dual-wavelength thulium-doped silica fiber laser based on a nonlinear amplifier loop mirror.

    PubMed

    Liu, Shuo; Yan, Fengping; Feng, Ting; Wu, Beilei; Dong, Ze; Chang, Gee-Kung

    2014-08-20

    A kind of switchable and spacing-tunable dual-wavelength thulium-doped silica fiber laser based on a nonlinear amplifier loop mirror is presented and experimentally demonstrated. By adjusting the polarization controllers (PCs), stable dual-wavelength operation is obtained at the 2 μm band. The optical signal-to-noise ratio (OSNR) is better than 56 dB. The wavelength tuning is performed by applying static strain into the fiber Bragg grating. A tuning range from 0 to 5.14 nm is achieved for the dual-wavelength spacing. By adjusting the PCs properly, the fiber laser can also operate in single-wavelength state with the OSNR for each wavelength more than 50 dB.

  15. Novel technique for mode selection in a multimode fiber laser.

    PubMed

    Daniel, J M O; Chan, J S P; Kim, J W; Sahu, J K; Ibsen, M; Clarkson, W A

    2011-06-20

    A simple technique for transverse mode selection in a large-mode-area (multimode) fiber laser is described. The technique exploits the different spectral responses of feedback elements based on a fiber Bragg grating and a volume Bragg grating to achieve wavelength-dependent mode filtering. This approach has been applied to a cladding-pumped thulium-doped fiber laser with a multimode core to achieve a single-spatial-mode output beam with a beam propagation factor (M2) of 1.05 at 1923 nm. Without mode selection the free-running fiber laser has a multimode output beam with an M2 parameter of 3.3. Selective excitation of higher order modes is also possible via the technique and preliminary results for laser oscillation on the LP11 mode are also discussed along with the prospects for scaling to higher power levels.

  16. Terahertz radiation using log-spiral-based low-temperature-grown InGaAs photoconductive antenna pumped by mode-locked Yb-doped fiber laser.

    PubMed

    Kong, Moon Sik; Kim, Ji Su; Han, Sang Pil; Kim, Namje; Moon, Kiwon; Park, Kyung Hyun; Jeon, Min Yong

    2016-04-01

    We demonstrate a terahertz (THz) radiation using log-spiral-based low-temperature-grown (LTG) InGaAs photoconductive antenna (PCA) modules and a passively mode-locked 1030 nm Yb-doped fiber laser. The passively mode-locked Yb-doped fiber laser is easily implemented with nonlinear polarization rotation in the normal dispersion using a 10-nm spectral filter. The laser generates over 250 mW of the average output power with positively chirped 1.58 ps pulses, which are dechirped to 127 fs pulses using a pulse compressor outside the laser cavity. In order to obtain THz radiation, a home-made emitter and receiver constructed from log-spiral-based LTG InGaAs PCA modules were used to generate and detect THz signals, respectively. We successfully achieved absorption lines over 1.5 THz for water vapor in free space. Therefore, we confirm that a mode-locked Yb-doped fiber laser has the potential to be used as an optical source to generate THZ waves.

  17. Mobile fiber-optic laser Doppler anemometer.

    PubMed

    Stieglmeier, M; Tropea, C

    1992-07-20

    A laser Doppler anemometer (LDA) has been developed that combines the compactness and low power consumption of laser diodes and avalanche photodiodes with the flexibility and possibility of miniaturization by using fiber-optic probes. The system has been named DFLDA for laser diode fiber LDA and is especially suited for mobile applications, for example, in trains, airplanes, or automobiles. Optimization considerations of fiber-optic probes are put forward and several probe examples are described in detail. Measurement results from three typical applications are given to illustrate the use of the DFLDA. Finally, a number of future configurations of the DFLDA concept are discussed.

  18. Femtosecond laser fabricated multimode fiber sensors interrogated by optical-carrier-based microwave interferometry technique for distributed strain sensing

    NASA Astrophysics Data System (ADS)

    Hua, Liwei; Song, Yang; Huang, Jie; Cheng, Baokai; Zhu, Wenge; Xiao, Hai

    2016-03-01

    A multimode fiber (MMF) based cascaded intrinsic Fabry-Perot interferometers (IFPIs) system is presented and the distributed strain sensing has been experimentally demonstrated by using such system. The proposed 13 cascaded IFPIs have been formed by 14 cascaded reflectors that have been fabricated on a grade index MMF. Each reflector has been made by drawing a line on the center of the cross-section of the MMF through a femtosecond laser. The distance between any two adjacent reflectors is around 100 cm. The optical carrier based microwave interferometry (OCMI) technique has been used to interrogate the MMF based cascaded FPIs system by reading the optical interference information in the microwave domain. The location along with the shift of the interference fringe pattern for each FPI can be resolved though signal processing based on the microwave domain information. The multimode interference showed very little influence to the microwave domain signals. By using such system the strain of 10-4 for each FPI sensor and the spatial resolution of less than 5 cm for the system can be easily achieved.

  19. 2.78 μm passively Q-switched Er3+-doped ZBLAN fiber laser based on PLD-Fe2+:ZnSe film

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Feng, Guoying; Zhang, Hong; Yang, Xianheng; Dai, Shenyu; Zhou, Shouhuan

    2016-07-01

    Based on the pulsed laser deposition (PLD) method, we first fabricated a mid-infrared Fe2+:ZnSe film saturable absorber (SA). By employing the PLD Fe2+:ZnSe film SA, we have demonstrated a passively Q-switched double-clad Er3+-doped ZBLAN fiber laser operating at a wavelength of 2.78 μm. Stable Q-switched pulses with pulse energy of 7.98 μJ and pulse duration of 0.742 μs, corresponding to a peak power of 10.76 W, were obtained at a repetition rate of 102.94 kHz. The maximum average output power is 822 mW. Our results demostrate that the PLD-Fe2+:ZnSe film SA is promising for high power pulse generation in compact mid-infrared fiber lasers.

  20. Fiber-optic-based laser vapor screen flow visualization system for aerodynamic research in larger scale subsonic and transonic wind tunnels

    NASA Technical Reports Server (NTRS)

    Erickson, Gary E.; Inenaga, Andrew S.

    1994-01-01

    Laser vapor screen (LVS) flow visualization systems that are fiber-optic based were developed and installed for aerodynamic research in the Langley 8-Foot Transonic Pressure Tunnel and the Langley 7- by 10-Foot High Speed Tunnel. Fiber optics are used to deliver the laser beam through the plenum shell that surrounds the test section of each facility and to the light-sheet-generating optics positioned in the ceiling window of the test section. Water is injected into the wind tunnel diffuser section to increase the relative humidity and promote condensation of the water vapor in the flow field about the model. The condensed water vapor is then illuminated with an intense sheet of laser light to reveal features of the flow field. The plenum shells are optically sealed; therefore, video-based systems are used to observe and document the flow field. Operational experience shows that the fiber-optic-based systems provide safe, reliable, and high-quality off-surface flow visualization in smaller and larger scale subsonic and transonic wind tunnels. The design, the installation, and the application of the Langley Research Center (LaRC) LVS flow visualization systems in larger scale wind tunnels are highlighted. The efficiency of the fiber optic LVS systems and their insensitivity to wind tunnel vibration, the tunnel operating temperature and pressure variations, and the airborne contaminants are discussed.

  1. High power passive mode-locked L-band fiber laser based on microfiber topological insulator saturable absorber

    NASA Astrophysics Data System (ADS)

    Semaan, Georges; Meng, Yichang; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Luo, Zhi-Chao; Sanchez, Francois

    2016-04-01

    In this communication, we demonstrate a passive mode-locked Er:Yb co-doped double-clad fiber laser using a tapered microfiber topological insulator (Bi2Se3) saturable absorber (TISA). The topological insulator is drop-casted onto the tapered fiber and optically deposited by optical tweezer effect. We use a ring laser setup including the fabricated TISA. By carefully optimizing the cavity losses and output coupling ratio, the mode-locked laser can operate in L-band with a high average output power. At a maximum pump power of 5 W, we obtain the 91st harmonic mode-locking of soliton bunches with a 3dB spectral bandwidth of 1.06nm, a repetition rate of 640.9 MHz and an average output power of 308mW. As far as we know, this is the highest output power yet reported of a mode-locked fiber laser operating with a TISA.

  2. Vibration sensor based on highly birefringent Bragg gratings written in standard optical fiber by a femtosecond laser

    NASA Astrophysics Data System (ADS)

    Chah, Karima; Bueno, Antonio; Kinet, Damien; Caucheteur, Christophe; Chluda, Cédric; Mégret, Patrice; Wuilpart, Marc

    2014-05-01

    We present a vibration sensor based on highly birefringent fiber Bragg gratings written in standard single mode optical fiber and realized with UV femtosecond pulses. This vibration sensor takes advantage of the stress-induced phase shift between the two orthogonally polarized fiber eigenmodes which induces intensity distribution changes in the two fiber Bragg grating reflection modes. The gratings are inscribed with the femtosecond line by line technique and have a birefringence value of 6 10-4. We demonstrate that theses gratings are temperature birefringence insensitive and ideal for vibration measurements.

  3. Thulium fiber laser lithotripsy using small spherical distal fiber tips

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

    2016-02-01

    This study tests a 100-μm-core fiber with 300-μm-diameter ball tip during Thulium fiber laser (TFL) lithotripsy. The TFL was operated at 1908 nm wavelength with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times measured, and ablation rates calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to observe ball tip degradation and determine number of procedures completed before need to replace fiber. Saline irrigation rates and ureteroscope deflection were measured with and without TFL fiber present. There was no statistical difference (P > 0.05) between stone ablation rates for single-use ball tip fiber (1.3 +/- 0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3 +/- 0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3 +/- 0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged > 4 stone procedures before decline in stone ablation rates due to mechanical damage at front surface of ball tip. The small fiber diameter did not impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and the ureter without risk of scope damage or tissue perforation, and without compromising stone ablation efficiency during TFL ablation of kidney stones.

  4. Thermal stress modification in regenerated fiber Bragg grating via manipulation of glass transition temperature based on CO₂-laser annealing.

    PubMed

    Lai, Man-Hong; Lim, Kok-Sing; Gunawardena, Dinusha S; Yang, Hang-Zhou; Chong, Wu-Yi; Ahmad, Harith

    2015-03-01

    In this work, we have demonstrated thermal stress relaxation in regenerated fiber Bragg gratings (RFBGs) by using direct CO₂-laser annealing technique. After the isothermal annealing and slow cooling process, the Bragg wavelength of the RFBG has been red-shifted. This modification is reversible by re-annealing and rapid cooling. It is repeatable with different cooling process in the subsequent annealing treatments. This phenomenon can be attributed to the thermal stress modification in the fiber core by means of manipulation of glass transition temperature with different cooling rates. This finding in this investigation is important for accurate temperature measurement of RFBG in dynamic environment. PMID:25723423

  5. Thulium-doped fiber laser utilizing a photonic crystal fiber-based optical low-pass filter with application in 1.7 μm and 1.8 μm band.

    PubMed

    Emami, Siamak Dawazdah; Khodaei, Amin; Gandan, Shumithira; Penny, Richard; Lim, Kok Sing; Abdul-Rashid, Hairul Azhar; Ahmad, Harith

    2015-07-27

    This paper describes a low pass filter based on photonics crystal fiber (PCF) partial ASE suppression, and its application within a 1.7 µm to 1.8 µm band thulium-doped fiber amplifier (TDFA) and a thulium-doped fiber laser (TDFL). The enlargement of air holes around the doped core region of the PCF resulted in a low-pass filter device that was able to attenuate wavelengths above the conventional long cut-off wavelength. These ensuing long cut-off wavelengths were 1.85 μm and 1.75 μm, and enabled a transmission mechanism that possessed a number of desirable characteristics. The proposed optical low-pass filter was applied within a TDFA and TDFL system. Peak spectrum was observed at around 1.9 μm for conventional TDF lasers, while the proposed TDF laser with PCF setup had fiber laser peak wavelengths measured at downshifted values of 1.74 μm and 1.81 μm. PMID:26367625

  6. All-fiber nonlinearity- and dispersion-managed dissipative soliton nanotube mode-locked laser

    SciTech Connect

    Zhang, Z.; Popa, D. Wittwer, V. J.; Milana, S.; Hasan, T.; Jiang, Z.; Ferrari, A. C.; Ilday, F. Ö.

    2015-12-14

    We report dissipative soliton generation from an Yb-doped all-fiber nonlinearity- and dispersion-managed nanotube mode-locked laser. A simple all-fiber ring cavity exploits a photonic crystal fiber for both nonlinearity enhancement and dispersion compensation. The laser generates stable dissipative solitons with large linear chirp in the net normal dispersion regime. Pulses that are 8.7 ps long are externally compressed to 118 fs, outperforming current nanotube-based Yb-doped fiber laser designs.

  7. Silver halide fiber-based evanescent-wave liquid droplet sensing with thermoelectrically cooled room temperature mid-infrared quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Chen, Jian Z.; Liu, Zhijun; Gmachl, Claire F.; Sivco, Deborah L.

    2005-11-01

    Quantum cascade lasers coupled directly to unclad silver halide fibers were used to assemble mid-infrared fiber-optics evanescent-wave sensors suitable to measure the chemical composition of simple liquid droplets. Quantum cascade lasers can be designed to emit across a wide range of mid-infrared wavelengths by tailoring the quantum-well structure, and the wavelength can be fine tuned by a thermoelectric cooler. Here, laser wavelengths were chosen which offer the largest absorption contrast between two constituents of a droplet. The laser was coupled to an unclad silver halide fiber, which penetrates through the droplet resting on a hydrophobic surface. For the same liquid composition and droplet size, the transmitted intensity is weaker for a droplet on a 1H,1H,2H,2H-perfluoro-octyltrichlorosilane coated glass slide than for one on a hexadecanethiol (HDT) coated Au-covered glass slide because of the high reflectivity of the HDT/Au surface at mid-infrared wavelengths. The absorption coefficients of water, glycerol, α-tocophenol acetate, and squalane were measured by varying the immersion length of the fiber; i.e. the droplet size. A pseudo-Beer-Lambert law fits well with the experimental data. We tested both aqueous liquid mixtures (acetone/water and ethanol/water) and oil-base solutions (n-dodecane/squalane and α-tocophenol acetate/squalane); α-tocophenol acetate and squalane are common ingredients of cosmetics, either as active ingredients or for chemical stabilization. Using a 300μm diameter silver halide fiber with a 25mm immersion length, the detection limits are 1 vol.% for α-tocophenol in squalane and 2 vol.% for acetone in water for laser wavenumbers of 1208 cm -1 and 1363 cm -1, respectively. This work was previously been reported in J. Z. Chen et al. Optics Express 13, 5953 (2005).

  8. Fiber laser front end for high energy petawatt laser systems

    SciTech Connect

    Dawson, J W; Messerly, M J; Phan, H; Mitchell, S; Drobshoff, A; Beach, R J; Siders, C; Lucianetti, A; Crane, J K; Barty, C J

    2006-06-15

    We are developing a fiber laser front end suitable for high energy petawatt laser systems on large glass lasers such as NIF. The front end includes generation of the pulses in a fiber mode-locked oscillator, amplification and pulse cleaning, stretching of the pulses to >3ns, dispersion trimming, timing, fiber transport of the pulses to the main laser bay and amplification of the pulses to an injection energy of 150 {micro}J. We will discuss current status of our work including data from packaged components. Design detail such as how the system addresses pulse contrast, dispersion trimming and pulse width adjustment and impact of B-integral on the pulse amplification will be discussed. A schematic of the fiber laser system we are constructing is shown in figure 1 below. A 40MHz packaged mode-locked fiber oscillator produces {approx}1nJ pulses which are phase locked to a 10MHz reference clock. These pulses are down selected to 100kHz and then amplified while still compressed. The amplified compressed pulses are sent through a non-linear polarization rotation based pulse cleaner to remove background amplified spontaneous emission (ASE). The pulses are then stretched by a chirped fiber Bragg grating (CFBG) and then sent through a splitter. The splitter splits the signal into two beams. (From this point we follow only one beam as the other follows an identical path.) The pulses are sent through a pulse tweaker that trims dispersion imbalances between the final large optics compressor and the CFBG. The pulse tweaker also permits the dispersion of the system to be adjusted for the purpose of controlling the final pulse width. Fine scale timing between the two beam lines can also be adjusted in the tweaker. A large mode area photonic crystal single polarization fiber is used to transport the pulses from the master oscillator room to the main laser bay. The pulses are then amplified a two stage fiber amplifier to 150mJ. These pulses are then launched into the main amplifier

  9. High-brightness, fiber-coupled pump modules in fiber laser applications

    NASA Astrophysics Data System (ADS)

    Hemenway, Marty; Urbanek, Wolfram; Hoener, Kylan; Kennedy, Keith W.; Bao, Ling; Dawson, David; Cragerud, Emily S.; Balsley, David; Burkholder, Gary; Reynolds, Mitch; Price, Kirk; Haden, Jim; Kanskar, Manoj; Kliner, Dahv A.

    2014-03-01

    High-power, high-brightness, fiber-coupled pump modules enable high-performance industrial fiber lasers with simple system architectures, multi-kW output powers, excellent beam quality, unsurpassed reliability, and low initial and operating costs. We report commercially available (element™), single-emitter-based, 9xx nm pump sources with powers up to 130 W in a 105 μm fiber and 250 W in a 200 μm fiber. This combination of high power and high brightness translates into improved fiber laser performance, e.g., simultaneously achieving high nonlinear thresholds and excellent beam quality at kW power levels. Wavelength-stabilized, 976 nm versions of these pumps are available for applications requiring minimization of the gain-fiber length (e.g., generation of high-peak-power pulses). Recent prototypes have achieved output powers up to 300 W in a 200 μm fiber. Extensive environmental and life testing at both the chip and module level under accelerated and real-world operating conditions have demonstrated extremely high reliability, with innovative designs having eliminated package-induced-failure mechanisms. Finally, we report integrated Pump Modules that provide < 1.6 kW of fiber-coupled power conveniently formatted for fiber-laser pumping or direct-diode applications; these 19" rack-mountable, 2U units combine the outputs of up to 14 elements™ using fused-fiber combiners, and they include high-efficiency diode drivers and safety sensors.

  10. Amplifier/compressor fiber Raman lasers.

    PubMed

    Islam, M N; Mollenauer, L F; Stolen, R H; Simpson, J R; Shang, H T

    1987-10-01

    We show that the chirp from cross-phase modulation (XPM) dominates the operation of fiber Raman lasers (FRL's). Thus a FRL in the anomalous group-velocity regime is best described as a XPM-chirped Raman amplifier followed by a linear fiber compressor. While the output of such a laser is generally a narrow pulse with a broad pedestal, we show both experimentally and by computer simulation that negligible background is achievable.

  11. Optical fiber-based photocathode

    NASA Astrophysics Data System (ADS)

    Cǎsǎndruc, Albert; Bücker, Robert; Kassier, Günther; Miller, R. J. Dwayne

    2016-08-01

    We present the design of a back-illuminated photocathode for electron diffraction experiments based on an optical fiber, and experimental characterization of emitted electron bunches. Excitation light is guided through the fiber into the experimental vacuum chamber, eliminating typical alignment difficulties between the emitter metal and the optical trigger and position instabilities, as well as providing reliable control of the laser spot size and profile. The in-vacuum fiber end is polished and coated with a 30 nm gold (Au) layer on top of 3 nm of chromium (Cr), which emits electrons by means of single-photon photoemission when femtosecond pulses in the near ultraviolet (257 nm) are fed into the fiber on the air side. The emission area can be adjusted to any value between a few nanometers (using tapered fibers) and the size of a multi-mode fiber core (100 μm or larger). In this proof-of-principle experiment, two different types of fibers were tested, with emission spot diameters of 50 μm and 100 μm, respectively. The normalized thermal electron beam emittance (TE) was measured by means of the aperture scan technique, and a TE of 4.0 π nm was measured for the smaller spot diameter. Straightforward enhancements to the concept allowed to demonstrate operation in an electric field environment of up to 7 MV/m.

  12. Yb-fiber-laser-based, 1.8 W average power, picosecond ultraviolet source at 266 nm.

    PubMed

    Chaitanya Kumar, S; Canals Casals, J; Sanchez Bautista, E; Devi, K; Ebrahim-Zadeh, M

    2015-05-15

    We report a compact, stable, high-power, picosecond ultraviolet (UV) source at 266 nm based on simple single-pass two-step fourth-harmonic generation (FHG) of a mode-locked Yb-fiber laser at 79.5 MHz in LiB3O5 (LBO) and β-BaB2O4. Using a 30-mm-long LBO crystal for single-pass second-harmonic generation, we achieve up to 9.1 W of average green power at 532 nm for 16.8 W of Yb-fiber power at a conversion efficiency of 54% in 16.2 ps pulses with a TEM00 spatial profile and passive power stability better than 0.5% rms over 16 h. The generated green radiation is then used for single-pass FHG into the UV, providing as much as 1.8 W of average power at 266 nm under the optimum focusing condition in the presence of spatial walk-off, at an overall FHG conversion efficiency of ∼11%. The generated UV output exhibits passive power stability better than 4.6% rms over 1.5 h and beam pointing stability better than 84 μrad over 1 h. The UV output beam has a circularity of >80% in high beam quality with the TEM00 mode profile. To the best of our knowledge, this is the first report of picosecond UV generation at 266 nm at megahertz repetition rates. PMID:26393749

  13. Fiber-laser-based, green-pumped, picosecond optical parametric oscillator using fan-out grating PPKTP.

    PubMed

    Chaitanya Kumar, S; Parsa, S; Ebrahim-Zadeh, M

    2016-01-01

    We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM00 mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied.

  14. Fiber-laser-based, green-pumped, picosecond optical parametric oscillator using fan-out grating PPKTP.

    PubMed

    Chaitanya Kumar, S; Parsa, S; Ebrahim-Zadeh, M

    2016-01-01

    We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM00 mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied. PMID:26696156

  15. Characterization of holmium fibers with various concentrations for fiber laser applications around 2.1 μm

    NASA Astrophysics Data System (ADS)

    Aubrecht, Jan; Peterka, Pavel; Honzatko, Pavel; Baravets, Yauhen; Jelinek, Michal; Kubecek, Vaclav; Pawliszewska, Maria; Sotor, Jaroslaw; Sobon, Grzegorz; Abramski, Krzysztof M.; Kasik, Ivan

    2016-04-01

    In this work, we present experimental results of characterization of the developed holmium-doped silica-based optical fibers with holmium ions concentrations in the range from 1000 to 10000 ppm. The fibers were fabricated by the modified chemical vapor deposition and solution doping method. They were characterized in terms of their spectral attenuation, refractive index profile, and especially performance in fiber laser. Simultaneously, two different fiber laser setups were tested. In the first one, holmium-doped fiber in Fabry-Perot configuration was pumping by in house developed thulium-doped fiber laser in ring arrangement. In the second one, bulk-optic pump-coupling configuration, consisted of a commercially available thulium fiber laser emitting at 1940 nm and system of lenses and mirrors was used. We have focused on comparison of laser output powers, slope efficiencies, and laser thresholds for individual holmiumdoped fiber in these different laser arrangements. Finally, the application of the developed fiber in subpicosecond fiber laser with graphene-based saturable absorber for mode-locking operation was investigated.

  16. Blade tip clearance measurement of the turbine engines based on a multi-mode fiber coupled laser ranging system.

    PubMed

    Guo, Haotian; Duan, Fajie; Wu, Guoxiu; Zhang, Jilong

    2014-11-01

    The blade tip clearance is a parameter of great importance to guarantee the efficiency and safety of the turbine engines. In this article, a laser ranging system designed for blade tip clearance measurement is presented. Multi-mode fiber is utilized for optical transmission to guarantee that enough optical power is received by the sensor probe. The model of the tiny sensor probe is presented. The error brought by the optical path difference of different modes of the fiber is estimated and the length of the fiber is limited to reduce this error. The measurement range in which the optical power received by the probe remains essentially unchanged is analyzed. Calibration experiments and dynamic experiments are conducted. The results of the calibration experiments indicate that the resolution of the system is about 0.02 mm and the range of the system is about 9 mm.

  17. Blade tip clearance measurement of the turbine engines based on a multi-mode fiber coupled laser ranging system

    SciTech Connect

    Guo, Haotian; Duan, Fajie; Wu, Guoxiu; Zhang, Jilong

    2014-11-15

    The blade tip clearance is a parameter of great importance to guarantee the efficiency and safety of the turbine engines. In this article, a laser ranging system designed for blade tip clearance measurement is presented. Multi-mode fiber is utilized for optical transmission to guarantee that enough optical power is received by the sensor probe. The model of the tiny sensor probe is presented. The error brought by the optical path difference of different modes of the fiber is estimated and the length of the fiber is limited to reduce this error. The measurement range in which the optical power received by the probe remains essentially unchanged is analyzed. Calibration experiments and dynamic experiments are conducted. The results of the calibration experiments indicate that the resolution of the system is about 0.02 mm and the range of the system is about 9 mm.

  18. Multiwavelength L-band fiber laser with bismuth-oxide EDF and photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ramzia Salem, A. M.; Al-Mansoori, M. H.; Hizam, H.; Mohd Noor, S. B.; Abu Bakar, M. H.; Mahdi, M. A.

    2011-05-01

    A multiwavelength laser comb using a bismuth-based erbium-doped fiber and 50 m photonic crystal fiber is demonstrated in a ring cavity configuration. The fiber laser is solely pumped by a single 1455 nm Raman pump laser to exploit its higher power delivery compared to that of a single-mode laser diode pump. At 264 mW Raman pump power and 1 mW Brillouin pump power, 38 output channels in the L-band have been realized with an optical signal-to-noise ratio above 15 dB and a Stokes line spacing of 0.08 nm. The laser exhibits a tuning range of 12 nm and produces stable Stokes lines across the tuning range between Brillouin pump wavelengths of 1603 nm and 1615 nm.

  19. High-power multichannel PPMgLN-based optical parametric oscillator pumped by a master oscillation power amplification-structured Q-switched fiber laser.

    PubMed

    Chen, Tao; Wei, Kaihua; Jiang, Peipei; Wu, Bo; Shen, Yonghang

    2012-10-01

    We experimentally demonstrated a compact fiber laser-pumped multichannel PPMgLN-based optical parametric oscillator (OPO) generating total OPO output power of 15.8, 15.2, 14.2, 12.9, and 8.8 W with idler output power of 4.7, 4.3, 4.1, 3.3, and 2.1 W at the wavelength of 3.43, 3.63, 3.72, 3.83, and 3.99 μm, respectively. The OPO was pumped by a fully fiberized polarization maintaining (PM) ytterbium-doped pulsed fiber master oscillation power amplifier (MOPA) operating at 1064 nm at a repetition rate of 65 kHz with effective pump power of 28.7 W. The MOPA system was constructed with an acousto-optic Q-switched fiber laser seed and only one stage PM fiber amplifier without any free space components, which makes the pump system compact and stable in the long-term. Comparisons on efficiencies and signal wavelength shifts between different channels showed that the idler absorption was the main factor preventing high average-power OPO operation with long idler wavelength. PMID:23033106

  20. Actively mode-locked Raman fiber laser.

    PubMed

    Yang, Xuezong; Zhang, Lei; Jiang, Huawei; Fan, Tingwei; Feng, Yan

    2015-07-27

    Active mode-locking of Raman fiber laser is experimentally investigated for the first time. An all fiber connected and polarization maintaining loop cavity of ~500 m long is pumped by a linearly polarized 1120 nm Yb fiber laser and modulated by an acousto-optic modulator. Stable 2 ns width pulse train at 1178 nm is obtained with modulator opening time of > 50 ns. At higher power, pulses become longer, and second order Raman Stokes could take place, which however can be suppressed by adjusting the open time and modulation frequency. Transient pulse evolution measurement confirms the absence of relaxation oscillation in Raman fiber laser. Tuning of repetition rate from 392 kHz to 31.37 MHz is obtained with harmonic mode locking. PMID:26367642

  1. Compact 35μm fiber coupled diode laser module based on dense wavelength division multiplexing of NBA mini-bars

    NASA Astrophysics Data System (ADS)

    Witte, U.; Traub, M.; Di Meo, A.; Hamann, M.; Rubel, D.; Hengesbach, S.; Hoffmann, D.

    2016-03-01

    We present a compact, modular and cross talk free approach for dense wavelength division multiplexing of high power diode lasers based on ultra-steep dielectric filters. The mini bars consist of 5 narrow stripe broad area emitters with a beam parameter product in the range of 2 mm mrad and a wavelength spacing of 2.5 nm between 2 adjacent emitters. Experimental results for fiber coupling (35 μm core diameter, NA < 0.2) of internally and externally stabilized diode lasers are presented. Optical losses are analyzed and alternative optical designs to overcome the current limitations of the setup are discussed.

  2. Tunable double-clad ytterbium-doped fiber laser based on a double-pass Mach-Zehnder interferometer

    NASA Astrophysics Data System (ADS)

    Meng, Yichang; Zhang, Shumin; Wang, Xinzhan; Du, Juan; Li, Hongfei; Hao, Yanping; Li, Xingliang

    2012-03-01

    We have demonstrated an adjustable double-clad Yb 3+-doped fiber laser using a double-pass Mach-Zehnder interferometer. The laser is adjustable over a range of 40 nm from 1064 nm to 1104 nm. By adjusting the state of the polarization controller, which is placed in the double-pass Mach-Zehnder interferometer, we obtained central lasing wavelengths that can be accurately tuned with controllable spacing between different tunable wavelengths. The laser has a side mode suppression ratio of 42 dB, the 3 dB spectral width is less than 0.2 nm, and the slope efficiencies at 1068 nm, 1082 nm and 1098 nm are 23%, 32% and 26%, respectively. In addition, we have experimentally observed tunable multi-wavelengths lasing output.

  3. A fiber Bragg grating sensor interrogation system based on a linearly wavelength-swept thermo-optic laser chip.

    PubMed

    Lee, Hyung-Seok; Lee, Hwi Don; Kim, Hyo Jin; Cho, Jae Du; Jeong, Myung Yung; Kim, Chang-Seok

    2014-08-29

    A linearized wavelength-swept thermo-optic laser chip was applied to demonstrate a fiber Bragg grating (FBG) sensor interrogation system. A broad tuning range of 11.8 nm was periodically obtained from the laser chip for a sweep rate of 16 Hz. To measure the linear time response of the reflection signal from the FBG sensor, a programmed driving signal was directly applied to the wavelength-swept laser chip. The linear wavelength response of the applied strain was clearly extracted with an R-squared value of 0.99994. To test the feasibility of the system for dynamic measurements, the dynamic strain was successfully interrogated with a repetition rate of 0.2 Hz by using this FBG sensor interrogation system.

  4. A Fiber Bragg Grating Sensor Interrogation System Based on a Linearly Wavelength-Swept Thermo-Optic Laser Chip

    PubMed Central

    Lee, Hyung-Seok; Lee, Hwi Don; Kim, Hyo Jin; Cho, Jae Du; Jeong, Myung Yung; Kim, Chang-Seok

    2014-01-01

    A linearized wavelength-swept thermo-optic laser chip was applied to demonstrate a fiber Bragg grating (FBG) sensor interrogation system. A broad tuning range of 11.8 nm was periodically obtained from the laser chip for a sweep rate of 16 Hz. To measure the linear time response of the reflection signal from the FBG sensor, a programmed driving signal was directly applied to the wavelength-swept laser chip. The linear wavelength response of the applied strain was clearly extracted with an R-squared value of 0.99994. To test the feasibility of the system for dynamic measurements, the dynamic strain was successfully interrogated with a repetition rate of 0.2 Hz by using this FBG sensor interrogation system. PMID:25177803

  5. Mode Selection for a Single-Frequency Fiber Laser

    NASA Technical Reports Server (NTRS)

    Liu, Jian

    2010-01-01

    A superstructured fiber-grating-based mode selection filter for a single-frequency fiber laser eliminates all free-space components, and makes the laser truly all-fiber. A ring cavity provides for stable operations in both frequency and power. There is no alignment or realignment required. After the fibers and components are spliced together and packaged, there is no need for specially trained technicians for operation or maintenance. It can be integrated with other modules, such as telescope systems, without extra optical alignment due to the flexibility of the optical fiber. The filter features a narrow line width of 1 kHz and side mode suppression ratio of 65 dB. It provides a high-quality laser for lidar in terms of coherence length and signal-to-noise ratio, which is 20 dB higher than solid-state or microchip lasers. This concept is useful in material processing, medical equipment, biomedical instrumentation, and optical communications. The pulse-shaping fiber laser can be directly used in space, airborne, and satellite applications including lidar, remote sensing, illuminators, and phase-array antenna systems.

  6. Black anneal marking with pulsed fiber lasers

    NASA Astrophysics Data System (ADS)

    Murphy, T.; Harrison, P.; Norman, S.

    2015-07-01

    High contrast marking of metals is used in a wide range of industries. Fiber laser marking of these metals provides non-contact marking with no consumables, offering many advantages over traditional methods of metal marking. The laser creates a permanent mark on the material surface combining heat and oxygen with no noticeable ablation. The focussed beam of the fiber laser in combination with precision control of the heat input is able to treat small areas of the material surface evenly and consistently, which is critical for producing black anneal marks. The marks are highly legible which is ideal for marking serial numbers or small data matrices where traceability is required. This paper reports the experimental study for producing black anneal marks on various grades of stainless steel using fiber lasers. The influence of metal surface finish, beam quality, spot size diameter and pulse duration are investigated for producing both smooth and decorative anneal marks.

  7. Fiber Delivery of mid-IR lasers

    SciTech Connect

    Kriesel, J.M.; Gat, N.; Bernacki, Bruce E.; Myers, Tanya L.; Bledt, Carlos M.; Harrington, James P.

    2011-08-24

    Fiber optics for the visible to near infrared (NIR) wavelength regimes (i.e. = 0.42 {mu}m) have proven to be extremely useful for a myriad of applications such as telecommunications, illumination, and sensors because they enable convenient, compact, and remote delivery of laser beams. Similarly, there is a need for fiber optics operating at longer wavelengths. For example, systems operating in the mid-IR regime (i.e., = 314 {mu}m) are being developed to detect trace molecular species with far-reaching applications, such as detecting explosives on surfaces, pollutants in the environment, and biomarkers in the breath of a patient. Furthermore, with the increasing availability of quantum cascade lasers (QCLs) which are semiconductor lasers that operate in the mid-IR regime additional uses are rapidly being developed. Here, we describe the development of hollow-core fibers for delivery of high-quality mid-IR laser beams across a broad spectral range.

  8. Laser speckle imaging of atherosclerotic plaques through optical fiber bundles.

    PubMed

    Nadkarni, Seemantini K; Bouma, Brett E; Yelin, Dvir; Gulati, Amneet; Tearney, Guillermo J

    2008-01-01

    Laser speckle imaging (LSI), a new technique that measures an index of plaque viscoelasticity, has been investigated recently to characterize atherosclerotic plaques. These prior studies demonstrated the diagnostic potential of LSI for detecting high-risk plaques and were conducted ex vivo. To conduct intracoronary LSI in vivo, the laser speckle pattern must be transmitted from the coronary wall to the image detector in the presence of cardiac motion. Small-diameter, flexible optical fiber bundles, similar to those used in coronary angioscopy, may be incorporated into an intravascular catheter for this purpose. A key challenge is that laser speckle is influenced by inter-fiber leakage of light, which may be exacerbated during bundle motion. In this study, we tested the capability of optical fiber bundles to transmit laser speckle patterns obtained from atherosclerotic plaques and evaluated the influence of motion on the diagnostic accuracy of fiber bundle-based LSI. Time-varying helium-neon laser speckle images of aortic plaques were obtained while cyclically moving the flexible length of the bundle to mimic coronary motion. Our results show that leached fiber bundles may reliably transmit laser speckle images in the presence of cardiac motion, providing a viable option to conduct intracoronary LSI. PMID:19021396

  9. Beam shaping design for compact and high-brightness fiber-coupled laser-diode system.

    PubMed

    Yu, Junhong; Guo, Linui; Wu, Hualing; Wang, Zhao; Tan, Hao; Gao, Songxin; Wu, Deyong; Zhang, Kai

    2015-06-20

    Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. A compact and high-brightness fiber-coupled system has been designed based on a significant beam shaping method. The laser-diode stack consists of eight mini-bars and is effectively coupled into a standard 100 μm core diameter and NA=0.22 fiber. The simulative result indicates that the module will have an output power over 440 W. Using this technique, compactness and high-brightness production of a fiber-coupled laser-diode module is possible.

  10. Part-per-trillion level SF6 detection using a quartz enhanced photoacoustic spectroscopy-based sensor with single-mode fiber-coupled quantum cascade laser excitation.

    PubMed

    Spagnolo, Vincenzo; Patimisco, Pietro; Borri, Simone; Scamarcio, Gaetano; Bernacki, Bruce E; Kriesel, Jason

    2012-11-01

    A sensitive spectroscopic sensor based on a hollow-core fiber-coupled quantum cascade laser (QCL) emitting at 10.54 μm and quartz enhanced photoacoustic spectroscopy (QEPAS) technique is reported. The design and realization of mid-IR fiber and coupler optics has ensured single-mode QCL beam delivery to the QEPAS sensor. The collimation optics was designed to produce a laser beam of significantly reduced beam size and waist so as to prevent illumination of the quartz tuning fork and microresonator tubes. SF(6) was selected as the target gas. A minimum detection sensitivity of 50 parts per trillion in 1 s was achieved with a QCL power of 18 mW, corresponding to a normalized noise-equivalent absorption of 2.7×10(-10) W·cm(-1)/Hz(1/2).

  11. Part-Per-Trillion Level SF6 Detection Using a Quartz Enhanced Photoacoustic Spectroscopy-Based Sensor with Single-Mode Fiber-Coupled Quantum Cascade Laser Excitation

    SciTech Connect

    Spagnolo, V.; Patimisco, P.; Borri, Simone; Scamarcio, G.; Bernacki, Bruce E.; Kriesel, J.M.

    2012-10-23

    A sensitive spectroscopic sensor based on a hollow-core fiber-coupled quantum cascade laser (QCL) emitting at 10.54 µm and quartz enhanced photoacoustic spectroscopy (QEPAS) technique is reported. The design and realization of mid-infrared fiber and coupler optics has ensured single-mode QCL beam delivery to the QEPAS sensor . The collimation optics was designed to produce a laser beam of significantly reduced beam size and waist so as to prevent illumination of the quartz tuning fork and micro-resonator tubes. SF6 was selected as the target gas. A minimum detection sensitivity of 50 parts per trillion in 1 s was achieved with a QCL power of 18 mW, corresponding to a normalized noise-equivalent absorption of 2.7x10-10 W•cm-1/Hz1/2.

  12. Echelle spectrograph calibration with a frequency comb based on a harmonically mode-locked fiber laser: a proposal

    SciTech Connect

    McFerran, J. J.

    2009-05-10

    Details for constructing an astronomical frequency comb suitable as a wavelength reference for echelle spectrographs associated with optical telescopes are outlined. The source laser for the frequency comb is a harmonically mode-locked fiber laser with a central wavelength of 1.56 {mu}m. The means of producing a repetition rate greater than 7 GHz and a peak optical power of {approx}8 kW are discussed. Conversion of the oscillator light into the visible can occur through a two-step process of (i) nonlinear conversion in periodically poled lithium niobate and (ii) spectral broadening in photonic crystal fiber. While not necessarily octave spanning in spectral range to permit the use of an f -to- 2f interferometer for offset frequency control, the frequency comb can be granted accuracy by linking the mode spacing and a comb tooth to separate frequency references. The design avoids the use of a Fabry-Perot cavity to increase the mode spacing of the frequency comb; however, the level of supermode suppression and sideband asymmetry in the fiber oscillator and in the subsequent frequency conversion stages are aspects that need to be experimentally tested.

  13. Highly sensitive liquid-level sensor based on dual-wavelength double-ring fiber laser assisted by beat frequency interrogation.

    PubMed

    Dai, Yi; Sun, Qizhen; Tan, Sisi; Wo, Jianghai; Zhang, Jiejun; Liu, Deming

    2012-12-01

    A highly sensitive liquid-level sensor based on dual-wavelength single-longitudinal-mode fiber laser is proposed and demonstrated. The laser is formed by exploiting two parallel arranged phase-shift fiber Bragg gratings (ps-FBGs), acting as ultra-narrow bandwidth filters, into a double-ring resonators. By beating the dual-wavelength lasing output, a stable microwave signal with frequency stability better than 5 MHz is obtained. The generated beat frequency varies with the change of dual-wavelength spacing. Based on this characteristic, with one ps-FBG serving as the sensing element and the other one acting as the reference element, a highly sensitive liquid level sensor is realized by monitoring the beat frequency shift of the laser. The sensor head is directly bonded to a float which can transfer buoyancy into axial strain on the fiber without introducing other elastic elements. The experimental results show that an ultra-high liquid-level sensitivity of 2.12 × 10(7) MHz/m within the measurement range of 1.5 mm is achieved. The sensor presents multiple merits including ultra-high sensitivity, thermal insensitive, good reliability and stability.

  14. Resonant cavity based time-domain multiplexing techniques for coherently combined fiber laser systems

    NASA Astrophysics Data System (ADS)

    Zhou, T.; Ruppe, J.; Stanfield, P.; Nees, J.; Wilcox, R.; Galvanauskas, A.

    2015-10-01

    This paper describes novel time-domain multiplexing techniques that use various resonant cavity configurations for increasing pulse energy extraction per each parallel amplification channel of a coherently combined array. Two different techniques are presented: a so-called N2 coherent array combining technique, applicable to a periodic pulse train, and a coherent pulse stacking amplification (CPSA) technique, applicable to a pulse burst. The first technique is a coherent combining technique, which achieves simultaneous beam combining and time-domain pulse multiplexing/down-counting using traveling-wave Fabry-Perot type resonators. The second technique is purely a time-domain pulse multiplexing technique, used with either a single amplifier or an amplifier array, which uses traveling-wave Gires-Tourmois type resonators. The importance of these techniques is that they can enable stacking of very large number of pulses, thus increasing effective amplified-pulse duration potentially by 102 to 103 times, and reducing fiber array size by the corresponding factor. This could lead to very compact coherently combined arrays even for generating very high pulse energies in the range of 1 to 100 J.

  15. A self-consistent model for a SOA-based fiber ring laser including the mode-locked pulse properties

    NASA Astrophysics Data System (ADS)

    Zarikas, Vasilios; Vlachos, Kyriakos

    2006-07-01

    In this paper, we present a self-consistent model of an optically mode-locked semiconductor fiber ring laser. The fiber laser uses a semiconductor optical amplifier (SOA) as the gain medium, while mode-locking is achieved by its gain modulation, via an external optical pulsed signal. We solved the model analytically developing a novel technique, where we have assumed double saturation of the SOA by both the mode-locked and the externally introduced pulsed signal. The study revealed the locus of the laser parameters to achieve mode-locking. In particular, it was found that SOA gain and energy of the externally introduced signal are two critical parameters that must simultaneously set properly for exact mode-locking. Another outcome of our analysis is that the study of the chirp parameter should be carried out keeping the nonlinear terms of the SOA gain. We have also investigated a slightly detuning regime of operation that revealed a fast change of the mode-locking process.

  16. Carbon Dioxide Laser Fiber Optics In Endoscopy

    NASA Astrophysics Data System (ADS)

    Fuller, Terry A.

    1982-12-01

    Carbon dioxide laser surgery has been limited to a great extent to surgical application on the integument and accessible cavities such as the cervix, vagina, oral cavities, etc. This limitation has been due to the rigid delivery systems available to all carbon dioxide lasers. Articulating arms (series of hollow tubes connected by articulating mirrors) have provided an effective means of delivery of laser energy to the patient as long as the lesion was within the direct line of sight. Even direct line-of-sight applications were restricted to physical dimension of the articulating arm or associated hand probes, manipulators and hollow tubes. The many attempts at providing straight endoscopic systems to the laser only stressed the need for a fiber optic capable of carrying the carbon dioxide laser wavelength. Rectangular and circular hollow metal waveguides, hollow dielectric waveguides have proven ineffective to the stringent requirements of a flexible surgical delivery system. One large diameter (1 cm) fiber optic delivery system, incorporates a toxic thalliumAbased fiber optic material. The device is an effective alternative to an articulating arm for external or conventional laser surgery, but is too large and stiff to use as a flexible endoscopic tool. The author describes the first highly flexible inexpensive series of fiber optic systems suitable for either conventional or endoscopic carbon dioxide laser surgery. One system (IRFLEX 3) has been manufactured by Medlase, Inc. for surgical uses capable of delivering 2000w, 100 mJ pulsed energy and 15w continuous wave. The system diameter is 0.035 inches in diameter. Surgically suitable fibers as small as 120 um have been manufactured. Other fibers (IRFLEX 142,447) have a variety of transmission characteristics, bend radii, etc.

  17. Ho:YLF Laser Pumped by TM:Fiber Laser

    NASA Astrophysics Data System (ADS)

    Mizutani, Kohei; Ishii, Shoken; Itabe, Toshikazu; Asai, Kazuhiro; Sato, Atsushi

    2016-06-01

    A 2-micron Ho:YLF laser end-pumped by 1.94-micron Tm:fiber laser is described. A ring resonator of 3m length is adopted for the oscillator. The laser is a master oscillator and an amplifier system. It is operated at high repetition rate of 200-5000 Hz in room temperature. The laser outputs were about 9W in CW and more than 6W in Q-switched operation. This laser was developed to be used for wind and CO2 measurements.

  18. Thin gas cell with GRIN fiber lens for intra-cavity fiber laser gas sensors

    NASA Astrophysics Data System (ADS)

    Li, Mo; Dai, Jing-min; Peng, Gang-ding

    2009-07-01

    Fiber laser gas sensors based on the intra-cavity absorption spectroscopy require the use of gas cells. We propose a simple and reliable gas cell using graded-index fiber lens (GFL) based all-fiber collimator. Conventional gas cells usually utilize direct fiber-to-fiber coupling without collimators or graded-index (GRIN) lens as collimators. Direct fiberto- fiber gas cell has simple configuration, but it suffers from high coupling loss and stray light interference. Gas cells applying fiber pigtailed GRIN lens are advantageous to achieve low coupling loss. However, fiber pigtailed GRIN lens requires accurate and complicated alignment and glue packaging which could compromise long term reliability and thermal stability. The proposed technique fabricates all-fiber collimators by simply splicing a short section of gradedindex fiber to single mode fiber which is both compact and durable. With that collimator, the gas cell can be fabricated very thin and are suitable for extreme environments with high temperature and vibration. In this paper, we have carried out experiment and analysis to evaluate the proposed technique. The coupling efficiency is studied versus different GFL gradient parameter profiles using ray matrix transformation of the complex beam parameter. Experiments are also done to prove the practical feasibility of the collimator. The analysis indicates that gas cell using GFLs can overcome the disadvantages of traditional design; it may replace the conventional gas cells in practical applications.

  19. Microstructured optical fiber for in-phase mode selection in multicore fiber lasers.

    PubMed

    Chuncan, Wang; Fan, Zhang; Chu, Liu; Shuisheng, Jian

    2008-04-14

    The mode-selection method based on a single-mode microstructured optical fiber (MOF) in the multicore fiber (MCF) lasers is presented. With an appropriate choice of the designed parameters of the MOF, the power coupling coefficient between the fundamental mode (FM) of the MOF and the in-phase mode can be much higher than those between the FM and the other supermodes. As a result, the in-phase mode has the highest power reflection on the right-hand side of the MCF laser cavity, and dominates the output laser power. Compared to the MCF lasers based on the free-space Talbot cavity method, the MCF lasers with the MOF as a mode-selection component have higher effectiveness of the in-phase mode selection.

  20. The crucial fiber components and gain fiber for high power ytterbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Liao, Lei; Liu, Peng; Xing, Ying-Bin; Wang, Yi-Bo; Dai, Neng-Li; Li, Jin-Yan; He, Bing; Zhou, Jun

    2015-08-01

    We have demonstrated a kW continuous-wave ytterbium-doped all-fiber laser oscillator with 7×1 fused fiber bundle combiner, fiber Bragg grating (FBG) and double-clad gain fiber fabricated by corresponding technologies. The results of experiment that the oscillator had operated at 1079.48nm with 80.94% slope efficiency without the influence of temperature and non-linear effects indicate that fiber components and gain fiber were suitable to high power environment. No evidence of the signal power roll-over showed that this oscillator possess the capacity to highest output with available pump power.

  1. Design, development, and operation of a fiber-based Cherenkov beam loss monitor at the SPring-8 Angstrom Compact Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Maréchal, X.-M.; Asano, Y.; Itoga, T.

    2012-05-01

    A fiber-based Cherenkov beam loss monitor (CBLM) consisting of large core (400 μm), long (≥150 m) multimode fibers, has been developed as an online long-range detection tool with high sensitivity and good position resolution for the 8 GeV SPring-8 Angstrom Compact Free Electron Laser: primarily designed for radiation safety in order to limit the dose outside the shielding of the machine, this monitor also serves as an early warning tool to avoid radiation damages done by lost electrons to the undulator magnets. This paper presents the approach chosen to insure that the required sensitivity (≤1 pC) could be obtained over more than 100 m. A beam-based approach was used to characterize (attenuation and signal strength) different fibers (diameter, index profile, and numerical aperture) and to select the most appropriate one. The response of the detector has also been studied numerically for different geometries (vacuum pipe and in-vacuum type undulators), beam energies, and beam loss scenarios, to determine the optimum number of fibers and their position in order to achieve the required detection limit. The results of the first few months of operation show that the SPring-8 CBLM can detect beam losses of less than 0.5 pC over the full 150 m length of the fiber.

  2. Performance comparison of an all-fiber-based laser Doppler vibrometer for remote acoustical signal detection using short and long coherence length lasers.

    PubMed

    Li, Rui; Madampoulos, Nicholas; Zhu, Zhigang; Xie, Liangping

    2012-07-20

    All-fiber laser Doppler vibrometer systems have great potential in the application of remote acoustic detection. However, due to the requirement for a long operating distance, a long coherence length laser is required, which can drive the system cost high. In this paper, a system using a short coherence length laser is proposed and demonstrated. Experimental analysis indicates that the multi-longitudinal modes of the laser cause detection noise and that the unequal length between two paths (local oscillator path and transmission path) increases the intensity and the frequency components of the noise. In order to reduce the noise, the optical length of the two paths needs to be balanced, within the coherence length of the source. We demonstrate that adopting a tunable optical delay to compensate the unequal length significantly reduces the noise. In a comparison of the detection results by using a short coherence laser and a long coherence laser, our developed system gives a good performance on the acoustic signal detection from three meters away.

  3. Ceramic bracket debonding with ytterbium fiber laser.

    PubMed

    Sarp, Ayşe Sena Kabaş; Gülsoy, Murat

    2011-09-01

    Since the early 1990 s, lasers have been used experimentally for debonding ceramic brackets. Lasers reduce the required debonding force and risk of enamel damage. However, the thermal effect during the laser radiation on dental tissues can cause undesirable results. The aim of this study is to develop a laser debonding technique for ceramic brackets that is better than mechanical debonding and also to minimize the side-effects of laser applications. A new fiber laser (1,070-nm ytterbium fiber laser) was tested, debonding procedure was quantified with a universal testing machine, and intrapulpal temperature was monitored for limiting the injury or pain. Experiments were performed in two sections according to the type of lasing mode: continuous wave (CW) and modulated mode. In continuous wave (CW) mode, a laser was applied on samples with different constant power levels continuously. In the second set of experiments, brackets were irradiated in modulated mode, in which the laser energy was delivered with on-and-off cycles. Laser power and duty cycles were adjusted by controlling the current, which was set to 4.99 A of current for 18 W of emission. Debonding force, debonding time, and work done by a universal testing machine were all significantly decreased for both modalities of laser irradiation compared to the control group. When laser parameters were set to proper doses, a 50% of reduction in required load for debonding and a three-fold decrease in debonding time were observed. Intrapulpal temperature changes were below the accepted threshold value (5.5°C) until the level of 3.5 W of laser power in continuous wave mode. During debonding, the work done by the universal testing machine is decreased up to five times by irradiation. Parameters were compared for both modes of operations and it was concluded that modulated mode laser application (Group 300/900) provided faster and easier debonding with less temperature change.

  4. All-fiber 7 × 1 signal combiner for high power fiber lasers.

    PubMed

    Zhou, Hang; Chen, Zilun; Zhou, Xuanfeng; Hou, Jing; Chen, Jinbao

    2015-04-10

    We present an all-fiber 7×1 signal combiner for high power fiber lasers. Through theoretical analysis, the fabrication method is confirmed and the taper length of the fiber bundle is chosen to be 1 cm to ensure a high transmission efficiency of the combiner. Based on the theoretical results, an all-fiber 7×1 signal combiner with high transmission efficiency is fabricated. A capillary with low refractive index is fused around the bundle of signal fibers to make an additional cladding layer. Then the fiber bundle is tapered to match the core of the output fiber and then spliced with the output fiber. The combiner is tested with a 500 W fiber laser and a temperature increase of 13°C/kW without any active cooling is observed in the combiner. The power transmission efficiency is measured to be close to 99% for each input port and the beam quality M2 is around 10. PMID:25967291

  5. Mid-infrared supercontinuum generation based on cascaded Raman scattering in a few-mode As2S3 fiber pumped by a thulium-doped fiber laser.

    PubMed

    Yao, Jinmei; Zhang, Bin; Yin, Ke; Yang, Linyong; Hou, Jing; Lu, Qisheng

    2016-06-27

    By pumping a 1.7-m-long As2S3 fiber at 2050 nm directly, a fiber-based mid-infrared supercontinuum (SC) source with an output power of 366 mW is demonstrated. This is the first experimental demonstration to obtain such a mid-infrared SC in a piece of chalcogenide fiber pumped at 2 μm directly. The cut-off wavelength of the As2S3 fiber is 3.5 μm, indicating that it could support several modes at around 2 μm. It is found that nonlinear spectral broadening mechanisms in the few-mode chalcogenide fiber could be affected through adjusting the butt-coupling position. That is because different positions will excite different modes that correspondingly possess different nonlinearity and dispersion characteristics. When stimulated Raman scattering (SRS) corresponding to the excitation of the fundamental mode becomes dominant in this few-mode fiber, an efficient cascaded SRS-based SC is obtained with five Stokes peaks ranging from 2 μm to 3.4 μm. Results from numerical simulation are in accord with the experimental results, showing that it is feasible to obtain an SRS based mid-infrared SC in a step-index As2S3 fiber by using a 2 μm high peak power picosecond laser to pump directly. PMID:27410625

  6. A phase-stabilized carbon nanotube fiber laser frequency comb.

    PubMed

    Lim, Jinkang; Knabe, Kevin; Tillman, Karl A; Neely, William; Wang, Yishan; Amezcua-Correa, Rodrigo; Couny, François; Light, Philip S; Benabid, Fetah; Knight, Jonathan C; Corwin, Kristan L; Nicholson, Jeffrey W; Washburn, Brian R

    2009-08-01

    A frequency comb generated by a 167 MHz repetition frequency erbium-doped fiber ring laser using a carbon nanotube saturable absorber is phase-stabilized for the first time. Measurements of the in-loop phase noise show an integrated phase error on the carrier envelope offset frequency of 0.35 radians. The carbon nanotube fiber laser comb is compared with a CW laser near 1533 nm stabilized to the nu(1) + nu(3) overtone transition in an acetylene-filled kagome photonic crystal fiber reference, while the CW laser is simultaneously compared to another frequency comb based on a Cr:Forsterite laser. These measurements demonstrate that the stability of a GPS-disciplined Rb clock is transferred to the comb, resulting in an upper limit on the locked comb's frequency instability of 1.2 x 10(-11) in 1 s, and a relative instability of <3 x 10(-12) in 1 s. The carbon nanotube laser frequency comb offers much promise as a robust and inexpensive all-fiber frequency comb with potential for scaling to higher repetition frequencies.

  7. High-power frequency comb in the range of 2-2.15  μm based on a holmium fiber amplifier seeded by wavelength-shifted Raman solitons from an erbium-fiber laser.

    PubMed

    Coluccelli, Nicola; Cassinerio, Marco; Gambetta, Alessio; Laporta, Paolo; Galzerano, Gianluca

    2014-03-15

    We demonstrate a room-temperature high-power frequency comb source covering the spectral region from 2 to 2.15 μm. The source is based on a femtosecond erbium-fiber laser operating at 1.55 μm with a repetition rate of 250 MHz, wavelength-shifted up to 2.06 μm by the solitonic Raman effect, seeding a large-mode-area holmium (Ho) fiber amplifier pumped by a thulium (Tm) fiber laser emitting at 1.94 μm. The frequency comb has an integrated power of 2 W, with overall power fluctuations as low as 0.3%. The beatnote between the comb and a high-spectral-purity, single-frequency Tm-Ho laser has a linewidth of 32 kHz over 1 ms observation time, with a signal-to-noise ratio in excess of 30 dB.

  8. Precision laser processing for micro electronics and fiber optic manufacturing

    NASA Astrophysics Data System (ADS)

    Webb, Andrew; Osborne, Mike; Foster-Turner, Gideon; Dinkel, Duane W.

    2008-02-01

    The application of laser based materials processing for precision micro scale manufacturing in the electronics and fiber optic industry is becoming increasingly widespread and accepted. This presentation will review latest laser technologies available and discuss the issues to be considered in choosing the most appropriate laser and processing parameters. High repetition rate, short duration pulsed lasers have improved rapidly in recent years in terms of both performance and reliability enabling flexible, cost effective processing of many material types including metal, silicon, plastic, ceramic and glass. Demonstrating the relevance of laser micromachining, application examples where laser processing is in use for production will be presented, including miniaturization of surface mount capacitors by applying a laser technique for demetalization of tracks in the capacitor manufacturing process and high quality laser machining of fiber optics including stripping, cleaving and lensing, resulting in optical quality finishes without the need for traditional polishing. Applications include telecoms, biomedical and sensing. OpTek Systems was formed in 2000 and provide fully integrated systems and sub contract services for laser processes. They are headquartered in the UK and are establishing a presence in North America through a laser processing facility in South Carolina and sales office in the North East.

  9. Sub-100 fs mode-locked erbium-doped fiber laser using a 45°-tilted fiber grating.

    PubMed

    Zhang, Zuxing; Mou, Chengbo; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin; Turitsyn, Sergei

    2013-11-18

    We demonstrate generation of sub-100 fs pulses at 1.5 µm in a mode-locked erbium-doped fiber laser using a 45°-tilted fiber grating element. The laser features a genuine all-fiber configuration. Based on the unique polarization properties of the 45°-tilted fiber grating, we managed to produce sub-100 fs laser pulses through proper dispersion management. To the best of our knowledge, this is the shortest pulse generated from mode-locked lasers with fiber gratings. The output pulse has an average power of 8 mW, with a repetition rate of 47.8 MHz and pulse energy of 1.68 nJ. The performance of laser also matches well the theoretical simulations.

  10. Fiber optic coherent laser radar 3d vision system

    SciTech Connect

    Sebastian, R.L.; Clark, R.B.; Simonson, D.L.

    1994-12-31

    Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  11. Hybrid fiber-rod laser

    DOEpatents

    Beach, Raymond J.; Dawson, Jay W.; Messerly, Michael J.; Barty, Christopher P. J.

    2012-12-18

    Single, or near single transverse mode waveguide definition is produced using a single homogeneous medium to transport both the pump excitation light and generated laser light. By properly configuring the pump deposition and resulting thermal power generation in the waveguide device, a thermal focusing power is established that supports perturbation-stable guided wave propagation of an appropriately configured single or near single transverse mode laser beam and/or laser pulse.

  12. Supercontinuum fiber lasers: new developments and applications

    NASA Astrophysics Data System (ADS)

    Devine, Adam; Hooper, Lucy; Clowes, John

    2016-05-01

    In this talk we give an overview of recent advances in the development of high power supercontinuum fiber lasers with powers exceeding 50W and spectral brightness of tens of mW/nm. We also discuss the fundamental limitations of power scaling and spectral broadening and review the existing and emerging applications of this unique light source which combines the broadband properties of a light bulb with the spatial properties of a laser.

  13. Experimental verification of fiber-coupling efficiency for satellite-to-ground atmospheric laser downlinks.

    PubMed

    Takenaka, Hideki; Toyoshima, Morio; Takayama, Yoshihisa

    2012-07-01

    Optical communication is a high-capacity method that can handle considerable satellite data. When common-fiber optical devices such as optical fiber amplifiers based on single mode fibers are used in free-space laser communication systems, the laser beam has to be coupled to a single-mode fiber. Under atmospheric turbulence it would be difficult to make the required fiber coupling efficiency in satellite-to-ground laser propagation paths. A fast-steering mirror that can operate at high frequencies under atmospheric turbulence is fabricated, and its tracking performance is verified in real satellite-to-ground laser communication experiments. The measured fiber coupling loss of 10-19 dB in satellite-to-ground laser communication links under atmospheric turbulence shows good agreement with the predicted fiber coupling efficiency of 17 dB.

  14. Coiled Fiber Pulsed Laser Simulator

    2009-01-29

    This suite of codes simulates the transient output pulse from an optically-pumped coiled fiber amplifier. The input pulse is assumed to have a Gaussian time dependence and a spatial dependence that may be Gaussian or an eigenmode of the straight of bent fiber computed using bend10 or bend20. Only one field component is used (semivectorial approximation). The fully-spatially-dependent fiber gain profile is specified is subroutines "inversion" and "interp_inversion" and is presently read from a datamore » file, although other means of specifying fiber gain could be reallized through modification of these subroutines. The input pulse is propagated through the fiber, including the following physical effects: spatial and temporal gain saturation, self-focusing, bend losses, and confinement from a user-defined fiber index profile. The user can follow the propagation progress with 3D graphics that show an intensity profile via user-modifiable cutting planes through the time space axes. A restart capability is also included. Approximate solutions in the frequency domain may be obtained much faster using the auxilliary codes bendbpm10 (full vector), bendbpm20 (semivectoral), and bendbpm21 (semivectoral with gain sheet spproximation for gain and self-focusing). These codes all include bend loss and spatial (but not temporal) gain saturation.« less

  15. Fiber based optofluidic biosensors

    NASA Astrophysics Data System (ADS)

    Lismont, M.; Vandewalle, N.; Joris, B.; Dreesen, L.

    2014-09-01

    Medicinal diagnosis requires the development of innovative devices allowing the detection of small amounts of biological species. Among the large variety of available biosensors, the ones based on fluorescence phenomenon are really promising. Here, we show a prototype of the basic unit of a multi-sensing biosensor combining optics and microfluidics benefits. This unit makes use of two crossed optical fibers: the first fiber is used to carry small probe molecules droplets and excite fluorescence, while the second one is devoted to target molecules droplets transport and fluorescence detection. Within this scheme, the interaction takes place in each fiber node. The main benefits of this detection setup are the absence of fibers functionalization, the use of microliter volumes of target and probe species, their separation before interaction, and a better detection limit compared to cuvettes setups.

  16. Spectral-domain OCT imaging using a spectrally flexible wavelength-swept fiber laser based on dispersion tuning

    NASA Astrophysics Data System (ADS)

    Takubo, Y.; Yamashita, S.

    2014-05-01

    The broadband source with the arbitrary spectrum based on dispersion tuning technique was demonstrated. While a dispersion-tuned wavelength-swept laser is capable of fast and widely wavelength sweep, it can also be used as a broadband spectrally-flexible source by controlling the sweep waveform. It is the first demonstration of spectrallytunable source to the best of our knowledge. We used the dispersion-tuned laser as a broadband source for SD-OCT system by synchronizing sweep rate of a laser and exposure time of a CCD camera in SD-OCT system. We successfully obtained the images of an adhesive tape and a human finger.

  17. Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

    PubMed

    Dawson, Jay W; Messerly, Michael J; Beach, Raymond J; Shverdin, Miroslav Y; Stappaerts, Eddy A; Sridharan, Arun K; Pax, Paul H; Heebner, John E; Siders, Craig W; Barty, C P J

    2008-08-18

    We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier. This power limit is determined by thermal and non-linear limits that combine to prevent further power scaling, irrespective of increases in mode size. However, limits to the scaling of the MFD may restrict fiber lasers to lower output powers.

  18. Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

    PubMed

    Dawson, Jay W; Messerly, Michael J; Beach, Raymond J; Shverdin, Miroslav Y; Stappaerts, Eddy A; Sridharan, Arun K; Pax, Paul H; Heebner, John E; Siders, Craig W; Barty, C P J

    2008-08-18

    We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier. This power limit is determined by thermal and non-linear limits that combine to prevent further power scaling, irrespective of increases in mode size. However, limits to the scaling of the MFD may restrict fiber lasers to lower output powers. PMID:18711562

  19. Torsion sensing characteristics of long period fiber gratings fabricated by femtosecond laser in optical fiber

    NASA Astrophysics Data System (ADS)

    Duan, Ji'an; Xie, Zheng; Wang, Cong; Zhou, Jianying; Li, Haitao; Luo, Zhi; Chu, Dongkai; Sun, Xiaoyan

    2016-09-01

    With the alignment of the fiber core systems containing dual-CCDs and high-precision electric displacement platform, twisted long period fiber gratings (T-LPFGs) were fabricated in two different twisted SMF-28 fibers by femtosecond laser. The torsion characteristics of the T-LPFGs were experimentally and theoretical investigated and demonstrated in this study. The achieved torsion sensitivity is 117.4 pm/(rad/m) in the torsion range -105-0 rad/m with a linearity of 0.9995. Experimental results show that compared with the ordinary long period fiber gratings, the resonance wavelength of the gratings presents an opposite symmetrical shift depending on the twisting direction after the applied torsion is removed. In addition, high sensitivity could be obtained, which is very suitable for the applications in the torsion sensor. These results are important for the design of new torsion sensors based on T-LPFGs fabricated by femtosecond laser.

  20. Constant Refractive Index Multi-Core Fiber Laser

    SciTech Connect

    Beach, R J; Feit, M D; Brasure, L D; Payne, S A; Mead, R W; Hayden, J S; Krashkevich, D; Alunni, D A

    2002-03-18

    A scalable fiber laser approach is described based on phase-locking multiple gain cores in an antiguided structure. The waveguide is comprised of periodic sequences of gain- and no-gain-loaded segments having uniform index, within the cladding region. Initial experimental results are presented.

  1. Analysis on error of laser frequency locking for fiber optical receiver in direct detection wind lidar based on Fabry-Perot interferometer and improvements

    NASA Astrophysics Data System (ADS)

    Zhang, Feifei; Dou, Xiankang; Sun, Dongsong; Shu, Zhifeng; Xia, Haiyun; Gao, Yuanyuan; Hu, Dongdong; Shangguan, Mingjia

    2014-12-01

    Direct detection Doppler wind lidar (DWL) has been demonstrated for its capability of atmospheric wind detection ranging from the troposphere to stratosphere with high temporal and spatial resolution. We design and describe a fiber-based optical receiver for direct detection DWL. Then the locking error of the relative laser frequency is analyzed and the dependent variables turn out to be the relative error of the calibrated constant and the slope of the transmission function. For high accuracy measurement of the calibrated constant for a fiber-based system, an integrating sphere is employed for its uniform scattering. What is more, the feature of temporally widening the pulse laser allows more samples be acquired for the analog-to-digital card of the same sampling rate. The result shows a relative error of 0.7% for a calibrated constant. For the latter, a new improved locking filter for a Fabry-Perot Interferometer was considered and designed with a larger slope. With these two strategies, the locking error for the relative laser frequency is calculated to be about 3 MHz, which is equivalent to a radial velocity of about 0.53 m/s and demonstrates the effective improvements of frequency locking for a robust DWL.

  2. Diffusing fiber tips for high-power medical laser applications

    NASA Astrophysics Data System (ADS)

    Schmitz, Christoph H.; Spaniol, Stefan B.; Abraham, Volkhard; Ashraf, Naim; Neuberger, Wolfgang; Ertmer, Wolfgang

    1995-01-01

    For most applications in laser medicine suitable delivery systems are required. We developed fiber optic based diffusing tips especially for photodynamic therapy (PDT) and laser induced thermotherapy (LITT). To realize an adequate emitting cylindrical diffuser the fiber core was abraded by a precision cutter. Hence, the use of scattering media such as TiO2-doped polymers is avoided. Because the diffuser size is mainly determined by the manipulated fiber and a surrounding glass capillary, one can realize small diameters ((phi) approximately equals 3 mm). The laser light is distributed mainly by surface scattering and total reflection at the fiber air boundary. Because the use of absorbing media is avoided, it is possible to apply high laser power as necessary in LITT and pulsed PDT. We produced diffusing tips with lengths of several centimeters and typical diameters of 3 mm. By controlling the fiber-shaping process, a homogeneous intensity profile or even special designs can be achieved. The control is done by either on-line camera surveillance or calculated predictions. A delivery system especially for the photodynamical treatment of female cervix dysplasia has been designed.

  3. Ultrafast pulses from a mid-infrared fiber laser.

    PubMed

    Hu, Tomonori; Jackson, Stuart D; Hudson, Darren D

    2015-09-15

    Ultrafast laser pulses at mid-infrared wavelengths (2-20 μm) interact strongly with molecules due to the resonance with their vibration modes. This enables their application in frequency comb-based sensing and laser tissue surgery. Fiber lasers are ideal to achieve these pulses, as they are compact, stable, and efficient. We extend the performance of these lasers with the production of 6.4 kW at a wavelength of 2.8 μm with complete electric field retrieval using frequency-resolved optical gating techniques. Contrary to the problems associated with achieving a high average power, fluoride fibers have now shown the capability of operating in the ultrafast, high-peak-power regime. PMID:26371902

  4. Highly polarized all-fiber thulium laser with femtosecond-laser-written fiber Bragg gratings.

    PubMed

    Willis, Christina C C; McKee, Erik; Böswetter, Pascal; Sincore, Alex; Thomas, Jens; Voigtländer, Christian; Krämer, Ria G; Bradford, Joshua D; Shah, Lawrence; Nolte, Stefan; Tünnermann, Andreas; Richardson, Martin

    2013-05-01

    We demonstrate and characterize a highly linearly polarized (18.8 dB) narrow spectral emission (<80 pm) from an all-fiber Tm laser utilizing femtosecond-laser-written fiber Bragg gratings. Thermally-dependent anisotropic birefringence is observed in the FBG transmission, the effects of which enable both the generation and elimination of highly linearly polarized output. To our knowledge, this is the first detailed study of such thermal anisotropic birefringence in femtosecond-written FBGs.

  5. A passively mode locked thulium doped fiber laser using bismuth telluride deposited multimode interference

    NASA Astrophysics Data System (ADS)

    Jung, M.; Lee, J.; Song, W.; Lee, J. H.; Shin, W.

    2016-03-01

    We experimentally demonstrate a passively mode-locked thulium doped fiber laser using a bismuth telluride deposited multimode interference (MMI) fiber at a wavelength of 1958 nm. Our MMI based saturable absorber was fabricated by fusion splicing with single mode fiber and null core fiber. The center wavelength and insertion loss of MMI fiber were measured to be ~ 1958 nm and 3.4 dB. We observed a passively mode locked thulium doped fiber laser operating at a wavelength of 1958 nm. The temporal pulse width of output pulses is 4.2 ps with repetition rate of 22.7 MHz.

  6. High power fiber delivery for laser ignition applications.

    PubMed

    Yalin, Azer P

    2013-11-01

    The present contribution provides a concise review of high power fiber delivery research for laser ignition applications. The fiber delivery requirements are discussed in terms of exit energy, intensity, and beam quality. Past research using hollow core fibers, solid step-index fibers, and photonic crystal and bandgap fibers is summarized. Recent demonstrations of spark delivery using large clad step-index fibers and Kagome photonic bandgap fibers are highlighted.

  7. Actively Q-switched Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. G.; Podivilov, E. V.; Babin, S. A.

    2015-03-01

    A new scheme providing actively Q-switched operation of a Raman fiber laser (RFL) has been proposed and tested. The RFL consists of a 1 km single-mode fiber with a switchable loop mirror at one end and an angled cleaved output end. An 1080 nm pulse with microsecond duration is generated at the output by means of acousto-optic switching of the mirror at ~30 kHz in the presence of 6 W backward pumping at 1030 nm. In the proposed scheme, the generated pulse energy is defined by the pump energy distributed along the passive fiber, which amounts to 30 μJ in our case. The available pump energy may be increased by means of fiber lengthening. Pulse shortening is also expected.

  8. Tunable microwave generation based on a dual-wavelength single-longitudinal-mode fiber laser using a phase-shifted grating on a triangular cantilever.

    PubMed

    Jiang, Meng; Lin, Bo; Shum, Perry Ping; Tjin, Swee Chuan; Dong, Xinyong; Sun, Qizhen

    2011-05-01

    Frequency tunable microwave signal generation, based on a dual-wavelength single-longitudinal-mode (SLM) erbium-doped fiber (EDF) laser, incorporating a phase-shifted fiber Bragg grating (PS-FBG) with two π-phase shifts, is demonstrated. In the proposed configuration, the PS-FBG with two ultranarrow transmission bands is embedded in a triangular cantilever to serve as a wavelength spacing tunable filter with a fixed center wavelength by applying various strains on the cantilever. A section of unpumped EDF is employed as a saturable absorber to ensure SLM operation in each of the two lasing lines. By beating the two wavelengths at a photodiode, a tunable microwave signal ranging from 8.835 to 24.360 GHz is successfully achieved.

  9. Employing dual-saturable-absorber-based filter for stable and tunable erbium-doped fiber ring laser in single-frequency

    NASA Astrophysics Data System (ADS)

    Yeh, C.-H.; Chow, C.-W.; Chen, K.-H.; Chen, J.-H.

    2011-05-01

    In this demonstration, a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser using dual-saturable-absorber-based (DSAB) filter inside loop cavity is proposed and experimentally investigated. The proposed DSAB filter not only can filter the side-mode in single-frequency output, but also can obtain the flattened output power spectrum within 1 dB variation in the effectively range of 1529 to 1563 nm. In addition, the output stabilities of wavelength and power are also measured experimentally and discussed.

  10. Frequency switched narrow linewidth microwave signal photonic generation based on a double-Brillouin-frequency spaced fiber laser.

    PubMed

    Zhang, Peng; Wang, Tianshu; Jia, Qingsong; Sun, Hongwei; Dong, Keyan; Liu, Xin; Kong, Mei; Jiang, Huilin

    2014-04-10

    A simple photonic approach to generate microwave frequency switched microwave signal is proposed and experimentally demonstrated. In this scheme, a Brillouin fiber laser with double-Brillouin-frequency spacing is used. The Brillouin ring configuration suppresses incoming Brillouin pump and even-order Stokes signals in the cavity. In addition, it also allows propagation of the odd-order Brillouin Stokes signals from configuration to output coupler. A dual-wavelength optical signal is heterodyned at the high-speed photodetector to produce a microwave signal. Frequency switched microwave signals, at 10.75 and 21.39 GHz, respectively, can be obtained through adjusting the polarization controller (PC) and loss of the variable optical attenuator (VOA).

  11. Supercontinuum generation based on all-normal-dispersion Yb-doped fiber laser mode-locked by nonlinear polarization rotation: Influence of seed's output port

    NASA Astrophysics Data System (ADS)

    Xiao, Xiaosheng; Hua, Yi

    2016-10-01

    All-normal-dispersion (ANDi) mode-locked Yb-doped fiber laser is a promising seed source for supercontinuum (SC) generation, due to its compact structure and broadband output. The influences of output ports of the ANDi laser mode-locked by nonlinear polarization rotation (NPR), on the generated SC are investigated. Two output ports of ANDi laser are considered, one of which is the conventional nonlinear polarization rotation (NPR) port and the other is extracted from a coupler after the NPR port. It is found that, the SC originated from the coupler port is much broader than that from the NPR port, which is validated by lots of experiments with different output parameters. Furthermore, the conclusion is verified and generalized to general ANDi lasers by numerical simulations, because the output pulse from coupler port could be cleaner than that from NPR port. Besides, there are no significant differences in the phase coherence and temporal stability between the SCs generated from both ports. Hence for the SC generation based on ANDi laser, it is preferred to use the pulse of coupler port (i.e. pulse after NPR port) serving as the seed source.

  12. Simultaneous 1310/1550 dual-band swept laser source and fiber-based dual-band common-path swept source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Mao, Youxin; Chang, Shoude; Murdock, Erroll; Flueraru, Costel

    2011-08-01

    A simultaneous two wavelength band swept laser source and a fiber-based dual-band common-path swept source optical coherence tomography is reported. Simultaneous 1310/1550 dual-wavelength tuning is performed by using two fiber-ring cavities with corresponding optical semiconductor amplifier as their gain mediums and two narrowband optical filters with a single dual-window polygonal scanner. Measured average output powers of 60 mW and 27 mW have been achieved for 1310 and 1550 nm bands, respectively, while the two wavelengths were swept simultaneously from 1227 nm to 1387 nm for 1310 nm band and from 1519 nm to 1581 nm for 1550 nm band at an A-scan rate of 65 kHz. A broadband 1310/1550 wavelength-division multiplexing is used for coupling two wavelengths into a common-path single-mode GRIN-lensed fiber probe to form a dual-band common-path swept-source optical coherence tomography. Simultaneous OCT imaging at 1310 and 1550 nm is achieved by using a depth ratio correction method. This technique allows potentially for in vivo endoscopic high-speed functional OCT imaging with high quality spectroscopic contrast with low computational costs. On the other hand, the common path configuration is able to reject common mode noise and potentially implement high stability quantitative phase measurements.

  13. Application of a high power Yb fiber-based laser compatible with commercial optical parametric oscillator for coherent anti-Stokes Raman scattering microscopy.

    PubMed

    Hage, Charles-Henri; Boisset, Simon; Ibrahim, Ali; Morin, Franck; Hoenninger, Clemens; Grunske, Tobias; Souissi, Sami; Heliot, Laurent; Leray, Aymeric

    2014-06-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is a powerful tool for chemical analysis at a subcellular level, frequently used for imaging lipid dynamics in living cells. We report a high-power picosecond fiber-based laser and its application for optical parametric oscillator (OPO) pumping and CARS microscopy. This fiber-based laser has been carefully characterized. It produces 5 ps pulses with 0.8 nm spectral width at a 1,030 nm wavelength with more than 10 W of average power at 80 MHz repetition rate; these spectral and temporal properties can be slightly modified. We then study the influence of these modifications on the spectral and temporal properties of the OPO. We find that the OPO system generates a weakly spectrally chirped signal beam constituted of 3 ps pulses with 0.4 nm spectral width tunable from 790 to 930 nm optimal for CARS imaging. The frequency doubling unconverted part is composed of 7-8 ps pulses with 0.75 nm spectral width compatible with CARS imaging. We also study the influence of the fiber laser properties on the CARS signal generated by distilled water. In agreement with theory, we find that shorter temporal pulses allow higher peak powers and thus higher CARS signal, if the spectral widths are less than 10 cm(-1) . We demonstrate that this source is suitable for performing CARS imaging of living cells during several hours without photodamages. We finally demonstrate CARS imaging on more complex aquatic organisms called copepods (micro-crustaceans), on which we distinguish morphological details and lipid reserves.

  14. Fast, long-scan-range pump-probe measurement based on asynchronous sampling using a dual-wavelength mode-locked fiber laser.

    PubMed

    Zhao, Xin; Zheng, Zheng; Liu, Lei; Wang, Qi; Chen, Haiwei; Liu, Jiansheng

    2012-11-01

    A simple, fast and long-scan-range pump-probe scheme is experimentally demonstrated using a dual-wavelength passively mode-locked fiber laser. The pulse trains from the dual-wavelength laser have a small difference in their repetition frequencies inherently determined by the intracavity dispersion. This enables the realization of the asynchronous sampling scheme with a tens-of-nanosecond-long delay range and a picosecond scan step at a millisecond scan speed. Instead of two synchronized ultrafast lasers in the traditional asynchronous sampling scheme, just one fiber laser is needed in our scheme, which could significantly simplify the system setup.

  15. All-fiber passively mode-locked Ho-laser pumped by ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Filatova, S. A.; Kamynin, V. A.; Zhluktova, I. V.; Trikshev, A. I.; Tsvetkov, V. B.

    2016-11-01

    We report an all-fiber mode-lock holmium-doped ring laser passively mode-locked by nonlinear polarization rotation without dispersion compensation. The laser produced picosecond pulses at 2.057 µm. The average output power was 4.5 mW.

  16. Use of hollow core fibers, fiber lasers, and photonic crystal fibers for spark delivery and laser ignition in gases

    SciTech Connect

    Joshi, Sachin; Yalin, Azer P.; Galvanauskas, Almantas

    2007-07-01

    The fiber-optic delivery of sparks in gases is challenging as the output beam must be refocused to high intensity ({approx}200 GW/cm2 for nanosecond pulses). Analysis suggests the use of coated hollow core fibers, fiber lasers, and photonic crystal fibers (PCFs). We study the effects of launch conditions and bending for 2 m long coated hollow fibers and find an optimum launch f of {approx}55 allowing spark formation with {approx}98% reliability for bends up to a radius of curvature of 1.5 m in atmospheric pressure air. Spark formation using the output of a pulsed fiber laser is described, and delivery of 0.55 mJ pulses through PCFs is shown.

  17. Multi-gigahertz repetition rate passively modelocked fiber lasers using carbon nanotubes.

    PubMed

    Martinez, Amos; Yamashita, Shinji

    2011-03-28

    There is an increasing demand for all-fiber passively mode-locked lasers with pulse repetition rates in the order of gigahertz for their potential applications in fields such as telecommunications and metrology. However, conventional mode-locked fiber lasers typically operate at fundamental repetition rates of only a few megahertz. In this paper, we report all-fiber laser operation with fundamental repetition rates of 4.24 GHz, 9.63 GHz and 19.45 GHz. This is, to date and to the best of our knowledge, the highest fundamental repetition rate reported for an all-fiber laser. The laser operation is based on the passive modelocking of a miniature all-fiber Fabry-Pérot laser (FFPL) by a carbon nanotube (CNT) saturable absorber. The key components for such device are a very high-gain Er:Yb phosphosilicate fiber and a fiber compatible saturable absorber with very small foot print and very low losses. The laser output of the three lasers was close to transform-limited with a pulsewidth of approximately 1 ps and low noise. As a demonstration of potential future applications for this laser, we also demonstrated supercontinuum generation with a longitudinal mode-spacing of 0.08 nm by launching the laser operating at 9.63 GHz into 30 m of a highly nonlinear dispersion shifted fiber.

  18. Fiber Coupled Laser Diodes with Even Illumination Pattern

    NASA Technical Reports Server (NTRS)

    Howard, Richard T. (Inventor)

    2007-01-01

    An optical fiber for evenly illuminating a target. The optical fiber is coupled to a laser emitting diode and receives laser light. The la ser light travels through the fiber optic and exits at an exit end. T he exit end has a diffractive optical pattern formed thereon via etch ing, molding or cutting, to reduce the Gaussian profile present in co nventional fiber optic cables The reduction of the Gaussian provides an even illumination from the fiber optic cable.

  19. Fiber lasers and amplifiers for science and exploration at NASA Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Abshire, James; Allan, Graham R.; Stephen Mark

    2005-01-01

    We discuss present and near-term uses for high-power fiber lasers and amplifiers for NASA- specific applications including planetary topography and atmospheric spectroscopy. Fiber lasers and amplifiers offer numerous advantages for both near-term and future deployment of instruments on exploration and science remote sensing orbiting satellites. Ground-based and airborne systems provide an evolutionary path to space and a means for calibration and verification of space-borne systems. We present experimental progress on both the fiber transmitters and instrument prototypes for ongoing development efforts. These near-infrared instruments are laser sounders and lidars for measuring atmospheric carbon dioxide, oxygen, water vapor and methane and a pseudo-noise (PN) code laser ranging system. The associated fiber transmitters include high-power erbium, ytterbium, neodymium and Raman fiber amplifiers. In addition, we will discuss near-term fiber laser and amplifier requirements and programs for NASA free space optical communications, planetary topography and atmospheric spectroscopy.

  20. Pulse bundles and passive harmonic mode-locked pulses in Tm-doped fiber laser based on nonlinear polarization rotation.

    PubMed

    Wang, Xiong; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-03-10

    We demonstrate the nanosecond-level pulses in Tm-doped fiber laser generated by passively harmonic mode-locking. Nonlinear polarization rotation performed by two polarization controllers (PCs) is employed to induce the self-starting harmonic mode-locking. The fundamental repetition rate of the laser is 448.8 kHz, decided by the length of the cavity. Bundles of pulses with up to 17 uniform subpulses are generated due to the split of pulse when the pump power increases and the PCs are adjusted. Continuous harmonic mode-locked pulse trains are obtained with 1st to 6th and even more than 15th order when the positions of the PCs are properly fixed and the pump power is scaled up. The widths of all the uniform individual pulses are mostly 3-5 ns, and pulse with width of 304 ns at fundamental repetition rate can also be generated by adjusting the PCs. Hysteresis phenomenon of the passively harmonic mode-locked pulses' repetition frequency versus pump power is observed. The rather wide 3dB spectral bandwidth of the pulse train (25 nm) indicates that they may resemble noise-like pulses. PMID:24663948

  1. Femtosecond mode-locked erbium-doped fiber laser based on MoS2-PVA saturable absorber

    NASA Astrophysics Data System (ADS)

    Ahmed, M. H. M.; Latiff, A. A.; Arof, H.; Ahmad, H.; Harun, S. W.

    2016-08-01

    We fabricate a free-standing few-layer molybdenum disulfide (MoS2)-polymer composite by liquid phase exfoliation of chemically pristine MoS2 crystals and use this to demonstrate a soliton mode-locked Erbium-doped fiber laser (EDFL). A stable self-started mode-locked soliton pulse is generated by fine-tuning the rotation of the polarization controller at a low threshold pump power of 25 mW. Its solitonic behavior is verified by the presence of Kelly sidebands in the output spectrum. The central wavelength, pulse width, and repetition rate of the laser are 1573.7 nm, 630 fs, and 27.1 MHz, respectively. The maximum pulse energy is 0.141 nJ with peak power of 210 W at pump power of 170 mW. This result contributes to the growing body of work studying the nonlinear optical properties of transition metal dichalcogenides that present new opportunities for ultrafast photonic applications.

  2. Demonstration of optical parametric gain generation in the 1 μm regime based on a photonic crystal fiber pumped by a picosecond mode-locked ytterbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Yang, Si-Gang; Wang, Xiao-Jian; Gou, Dou-Dou; Chen, Hong-Wei; Chen, Ming-Hua; Xie, Shi-Zhong

    2014-01-01

    We report the experimental demonstration of the optical parametric gain generation in the 1 μm regime based on a photonic crystal fiber (PCF) with a zero group velocity dispersion (GVD) wavelength of 1062 nm pumped by a homemade tunable picosecond mode-locked ytterbium-doped fiber laser. A broad parametric gain band is obtained by pumping the PCF in the anomalous GVD regime with a relatively low power. Two separated narrow parametric gain bands are observed by pumping the PCF in the normal GVD regime. The peak of the parametric gain profile can be tuned from 927 to 1038 nm and from 1099 to 1228 nm. This widely tunable parametric gain band can be used for a broad band optical parametric amplifier, large span wavelength conversion or a tunable optical parametric oscillator.

  3. All fiber laser using a ring cavity

    NASA Astrophysics Data System (ADS)

    Flores, Alberto Varguez; Pérez, Georgina Beltrán; Aguirre, Severino Muñoz; Mixcóatl, Juan Castillo

    2008-04-01

    Mode-locked laser have a number of potential applications, depending on the wavelength and pulse width. They could be used as sources in communications systems for time division multiplexing (TDM) or wavelength-division-multiplexing (WDM) as spectroscopic tools in the laboratory for time-resolved studies of fast nonlinear phenomena in semiconductors, or as seeds for solid-state amplifers such as Nd:Glass, color center alexandrite, or Ti:Sapphire. Short pulses also have potential use in electro-optic sampling systems, as a source for pulsed sensors, or as tunable seed pulses for lasers in medical applications. Applications such as optical coherent tomography could take advantage of the broad bandwidth of a mode-locked fiber laser rather that the temporal ultra-short pulse width. This work shows the characterization of active mode-locking all-fiber laser by using an acousto-optic frequency shifter to the ring cavity, an erbium doped fiber (EDF) and polarization controllers (PC). The results shows a highly stable mode-locked, low noise of pulse generation with repetition rate of 10 MHz and width of 1.6 ns

  4. QUANTITATIVE DETECTION OF ENVIRONMENTALLY IMPORTANT DYES USING DIODE LASER/FIBER-OPTIC RAMAN

    EPA Science Inventory

    A compact diode laser/fiber-optic Raman spectrometer is used for quantitative detection of environmentally important dyes. This system is based on diode laser excitation at 782 mm, fiber optic probe technology, an imaging spectrometer, and state-of-the-art scientific CCD camera. ...

  5. Mode-locked erbium-doped fiber laser based on evanescent field interaction with Sb{sub 2}Te{sub 3} topological insulator

    SciTech Connect

    Sotor, J. Sobon, G.; Abramski, K. M.; Grodecki, K.

    2014-06-23

    In this Letter, we demonstrate a mode-locked Er-doped fiber laser incorporating antimony telluride (Sb{sub 2}Te{sub 3}) topological insulator (TI) as a saturable absorber (SA). The laser was capable of generating 270 fs-short soliton pulses at 1560 nm wavelength, which are the shortest solitons generated with a TI-based saturable absorber so far. In order to form a saturable absorber, a bulk piece of Sb{sub 2}Te{sub 3} was deposited on a side-polished single-mode fiber with the presence of a low refractive index polymer. Such saturable absorber exhibits modulation depth at the level of 6% with less than 3 dB of non-saturable losses. Our study shows that TI-based saturable absorbers with evanescent field interaction might compete with SAs based on carbon nanomaterials, like graphene or nanotubes. Additionally, thanks to the interaction with the evanescent field, the material is not exposed to high optical power, which allows to avoid optical or thermal damage.

  6. Polarization-modulated random fiber laser

    NASA Astrophysics Data System (ADS)

    Wu, Han; Wang, Zinan; He, Qiheng; Fan, Mengqiu; Li, Yunqi; Sun, Wei; Zhang, Li; Li, Yi; Rao, Yunjiang

    2016-05-01

    In this letter, we propose and experimentally demonstrate a polarization-modulated random fiber laser (RFL) for the first time. It is found that the output power of the half-opened RFL with polarized pumping is sensitive to the state of polarization (SOP) of the Stokes light in a fiber loop acting as a mirror. By inserting a polarization switch (PSW) in the loop mirror, the state of the random lasing can be switched between on/off states, thus such a polarization-modulated RFL can generate pulsed output with high extinction ratio.

  7. Multi-watt 589nm fiber laser source

    SciTech Connect

    DAWSON, J W; DROBSHOFF, A D; BEACH, R J; MESSERLY, M J; PAYNE, S A; BROWN, A; PENNINGTON, D M; BAMFORD, D J; SHARPE, S J; COOK, D J

    2006-01-19

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichiometric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd{sup 3+} fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the competing 1088nm 4-level laser transition. At 15W, the 938nm laser has an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss the fiber laser design and operation as well as our results in power scaling at 589nm.

  8. An LSPR fiber optic sensor based on in-line micro-holes fabricated by a second harmonic 400nm femtosecond laser

    NASA Astrophysics Data System (ADS)

    Shiraishi, Masahiko; Goya, Kenji; Seki, Atsushi; Watanabe, Kazuhiro

    2016-02-01

    In this study, we have proposed a novel type of localized surface plasmon resonance (LSPR) fiber optic sensor based on in-line/pico-liter micro-holes which can be experimentally fabricated into the fiber waveguide by using a second harmonic 400 nm femtosecond laser. A repetitive pulse train of 1 kHz with a pulse width of 350 fs was irradiated onto a MMGI fiber optic to make three holes that penetrate through the fiber core and work as spectroscopic-microfluidic flow cells. In order to induce the interaction between transmitted light and gold nanoparticles (GNPs) adhered on the inner surface of the flow cells, micro-holes were designed to be the width of approximately 50 μm, along a direction perpendicular to an optical axis of an optical fiber. GNPs with approximately 100 nm of particle diameter adhered onto the inner surface according to 3-aminopropyltriethoxy silane treatment. The transmitted light through the micro-holes was obtained by optical instruments consisted of a white light source and an optical spectrum analyzer. In order to obtain the reference spectrum, the optical spectrum was acquired before dipping the sensor into the GNPs solution. After 30 min of immersing the sensor portion into the GNPs solution, the optical spectrum was also obtained. The reference spectrum which was considered as the baseline, was set to zero and then, the absorbance spectrum was calculated. The absorbance peak at a wavelength of 537 nm occurred in an air condition in the sensing area, which seemed like the resonance peak based on the LSPR.

  9. 600-Hz linewidth short-linear-cavity fiber laser.

    PubMed

    Mo, Shupei; Huang, Xiang; Xu, Shanhui; Li, Can; Yang, Changsheng; Feng, Zhouming; Zhang, Weinan; Chen, Dongdan; Yang, Zhongmin

    2014-10-15

    We proposed a short-linear-cavity (SLC) fiber laser based on a virtual-folded-ring (VFR) resonator and a fiber Bragg grating Fabry-Perot filter. Spatial hole burning effect was reduced by retarding the polarization state of the counter-propagating light waves utilizing the VFR structure. The photon lifetime of the resonator was extended due to the multi-reflection inside the FBG FP, which increased the intra-cavity power and relatively suppressed the contribution of phase diffusion from spontaneous emission. The relaxation oscillation frequency is around 160 kHz due to the slow light effect. The linewidth of the SLC fiber laser was measured to be less than 600 Hz.

  10. DFB fiber laser hydrophone with band-pass response.

    PubMed

    Zhang, Faxiang; Zhang, Wentao; Li, Fang; Liu, Yuliang

    2011-11-15

    A distributed-feedback fiber laser hydrophone with band-pass response is presented. The design of the hydrophone aims to equalize static pressure and eliminate signal aliasing of high-frequency acoustic components. Theoretical analysis is presented based on electro-acoustic theory. The experimental results agree well with the theory. The measured underwater responses show that the hydrophone has a pressure sensitivity of -170 dB re:pm/μPa over a bandwidth between 100 Hz and 500 Hz. A sensitivity reduction exceeding -35 dB is observed at 2500 Hz. The tested static pressure sensitivity of the hydrophone is -226 dB. The proposed fiber laser hydrophone of this kind is expected to have important application in deep water fiber-optic sonar systems with anti-aliasing, and the understanding gained through this work can be extended to a guide of hydrophone design for required filtering bandwidth.

  11. MOPA pulsed fiber laser for silicon scribing

    NASA Astrophysics Data System (ADS)

    Yang, Limei; Huang, Wei; Deng, Mengmeng; Li, Feng

    2016-06-01

    A 1064 nm master oscillator power amplifier (MOPA) pulsed fiber laser is developed with flexible control over the pulse width, repetition frequency and peak power, and it is used to investigate the dependence of mono-crystalline silicon scribe depth on the laser pulse width, scanning speed and repeat times. Experimental results indicate that long pulses with low peak powers lead to deep ablation depths. We also demonstrate that the ablation depth grows fast with the scanning repeat times at first and progressively tends to be saturated when the repeat times reach a certain level. A thermal model considering the laser pulse overlapping effect that predicts the silicon temperature variation and scribe depth is employed to verify the experimental conclusions with reasonably close agreement. These conclusions are of great benefits to the optimization of the laser material processing with high efficiency.

  12. High power 1018 nm monolithic Yb3+-doped fiber laser and amplifier High power 1018 nm monolithic Yb3+-doped fiber laser and amplifier

    NASA Astrophysics Data System (ADS)

    Xiao, H.; Zhou, P.; Wang, X. L.; Guo, S. F.; Xu, X. J.

    2012-10-01

    In this letter high power monolithic 1018 nm fiber laser and amplifier are presented. The output characteristics of 1018 nm laser with amplified spontaneous emission (ASE) feedback, fiber Bragg gratings (FBG) reflectivity, gain fiber length and other parameters are experimentally investigated. The difference between 1018 and 1064 nm amplification are also compared in experiment. Based on these experimental results, we find viable approaches to improve the laser and amplifier's performances. 85 W 1018 nm fiber laser with a slope efficiency of 71% and 110 W 1018 nm fiber amplifier with the slope efficiency of 77% are achieved, both of which we believe are the highest output at this wavelength that ever reported in open detail.

  13. Blackening of metals using femtosecond fiber laser.

    PubMed

    Huang, Huan; Yang, Lih-Mei; Bai, Shuang; Liu, Jian

    2015-01-10

    This study presents an unprecedented high throughput processing for super-blackening and superhydrophobic/hydrophilic surface on both planar and nonplanar metals surfaces. By using a high pulse repetition rate femtosecond (fs) fiber laser, a light trapping microstructure and nanostructure is generated to absorb light from UV, visible to long-wave infrared spectral region. Different types of surface structures are produced with varying laser scanning conditions (scanning speed and pitch). The modified surface morphologies are characterized using scanning electron microscope and the blackening effect is investigated through spectral measurements. Spectral measurements show that the reflectance of the processed materials decreases sharply in a wide wavelength range and the decrease occurs at different rates for different scanning pitches and speeds. Above 98% absorption over the entire visible wavelength region and above 95% absorption over the near-infrared, middle-wave infrared and long-wave infrared regions range has been demonstrated for the surface structures, and the absorption for specific wavelengths can go above 99%. Furthermore, the processing efficiency of this fs fiber laser blackening technique is 1 order of magnitude higher than that of solid-state fs laser and 4 times higher than that of picosecond (ps) laser. Further increasing of the throughput is expected by using higher repetition and higher scanning speed. This technology offers the great potential in applications such as constructing sensitive detectors and sensors, solar energy absorber, and biomedicine. PMID:25967633

  14. Broad-Area Laser Diode With Fiber-Optic Injection

    NASA Technical Reports Server (NTRS)

    Hazel, Geoffrey; Mead, Patricia; Davis, Christopher; Cornwell, Donald

    1992-01-01

    Fiber-optic injection-locked broad-area laser diode features single-mode output via fiber-optic injection and serves as compact, rugged, high-power near-infrared source. Useful in free-space and fiber-optic communication links, as communication-receiver preamplifier, and pump source for solid-state lasers.

  15. Drilling with fiber-transmitted, visible lasers

    SciTech Connect

    Kautz, D.D.; Berzins, L.V.; Dragon, E.P.; Werve, M.E.; Warner, B.E.

    1994-02-17

    High power and radiance copper-vapor laser technology developed at Lawrence Livermore National Laboratory shows great promise for many materials processing tasks. The authors recently transmitted the visible light produced by these lasers through fiber optics to perform hole drilling experiments. They found the tolerances on the hole circulatory and cylindricity to be excellent when compared to that produced by conventional optics. This technique lends itself to many applications that are difficult to perform when using conventional optics, including robotic manipulation and hole drilling in non-symmetric parts.

  16. Laser cutting of carbon fiber reinforced thermo-plastics (CFRTP) by single-mode fiber laser irradiation

    NASA Astrophysics Data System (ADS)

    Niino, Hiroyuki; Kawaguchi, Yoshizo; Sato, Tadatake; Narazaki, Aiko; Kurosaki, Ryozo; Muramatsu, Mayu; Harada, Yoshihisa; Anzai, Kenji; Aoyama, Mitsuaki; Matsushita, Masafumi; Furukawa, Koichi; Nishino, Michiteru; Fujisaki, Akira; Miyato, Taizo; Kayahara, Takashi

    2014-03-01

    We report on the laser cutting of carbon fiber reinforced thermo-plastics (CFRTP) with a cw IR fiber laser (single-mode fiber laser, average power: 350 W). CFRTP is a high strength composite material with a lightweight, and is increasingly being used various applications. A well-defined cutting of CFRTP which were free of debris and thermal-damages around the grooves, were performed by the laser irradiation with a fast beam galvanometer scanning on a multiple-scanpass method.

  17. Theory of a random fiber laser

    SciTech Connect

    Kolokolov, I. V. Lebedev, V. V.; Podivilov, E. V.; Vergeles, S. S.

    2014-12-15

    We develop the theory explaining the role of nonlinearity in generation of radiation in a fiber laser that is pumped by external light. The pumping energy is converted into the generating signal due to the Raman scattering supplying an effective gain for the signal. The signal is generated with frequencies near the one corresponding to the maximum value of the gain. Generation conditions and spectral properties of the generated signal are examined. We focus mainly on the case of a random laser where reflection of the signal occurs on impurities of the fiber. From the theoretical standpoint, kinetics of a wave system close to an integrable one are investigated. We demonstrate that in this case, the perturbation expansion in the kinetic equation has to use the closeness to the integrable case.

  18. 980 nm narrow linewidth Yb-doped phosphate fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Pingxue; Yao, Yifei; Hu, Haowei; Chi, Junjie; Yang, Chun; Zhao, Ziqiang; Zhang, Guangju

    2014-12-01

    A narrow-linewidth ytterbium (Yb)-doped phosphate fiber laser based on fiber Bragg grating (FBG) operating around 980 nm is reported. Two different kinds of cavity are applied to obtain the 980 nm narrow-linewidth output. One kind of the cavity consists of a 0.35 nm broadband lindwidth high-reflection FBG and the Yb-doped phosphate fiber end with 0° angle, which generates a maximum output power of 25 mW. The other kind of resonator is composed of a single mode Yb-doped phosphate fiber and a pair of FBGs. Over 10.7 mW stable continuous wave are obtained with two longitudinal modes at 980 nm. We have given a detailed analysis and discussion for the results.

  19. Multiplexing of six micro-displacement suspended-core Sagnac interferometer sensors with a Raman-Erbium fiber laser.

    PubMed

    Bravo, Mikel; Fernández-Vallejo, Montserrat; Echapare, Mikel; López-Amo, Manuel; Kobelke, J; Schuster, K

    2013-02-11

    This work experimentally demonstrates a long-range optical fiber sensing network for the multiplexing of fiber sensors based on photonic crystal fibers. Specifically, six photonic crystal fiber sensors which are based on a Sagnac interferometer that includes a suspended-core fiber have been used. These sensors offer a high sensitivity for micro-displacement measurements. The fiber sensor network presents a ladder structure and its operation mode is based on a fiber ring laser which combines Raman and Erbium doped fiber amplification. Thus, we show the first demonstration of photonic crystal fiber sensors for remote measurement applications up to 75 km. PMID:23481755

  20. High Power Fiber Lasers and Applications to Manufacturing

    NASA Astrophysics Data System (ADS)

    Richardson, Martin; McComb, Timothy; Sudesh, Vikas

    2008-09-01

    We summarize recent developments in high power fiber laser technologies and discuss future trends, particularly in their current and future use in manufacturing technologies. We will also describe our current research programs in fiber laser development, ultra-fast and new lasers, and will mention the expectations in these areas for the new Townes Laser Institute. It will focus on new core laser technologies and their applications in medical technologies, advanced manufacturing technologies and defense applications. We will describe a program on large mode area fiber development that includes results with the new gain-guiding approach, as well as high power infra-red fiber lasers. We will review the opportunities for high power fiber lasers in various manufacturing technologies and illustrate this with applications we are pursuing in the areas of femtosecond laser applications, advanced lithographies, and mid-IR technologies.

  1. Components for monolithic fiber chirped pulse amplification laser systems

    NASA Astrophysics Data System (ADS)

    Swan, Michael Craig

    The first portion of this work develops techniques for generating femtosecond-pulses from conventional fabry-perot laser diodes using nonlinear-spectral-broadening techniques in Yb-doped positive dispersion fiber ampliers. The approach employed an injection-locked fabry-perot laser diode followed by two stages of nonlinear-spectral-broadening to generate sub-200fs pulses. This thesis demonstrated that a 60ps gain-switched fabry-perot laser-diode can be injection-locked to generate a single-longitudinal-mode pulse and compressed by nonlinear spectral broadening to 4ps. Two problems have been identified that must be resolved before moving forward with this approach. First, gain-switched pulses from a standard diode-laser have a number of characteristics not well suited for producing clean self-phase-modulation-broadened pulses, such as an asymmetric temporal shape, which has a long pulse tail. Second, though parabolic pulse formation occurs for any arbitrary temporal input pulse profile, deviation from the optimum parabolic input results in extensively spectrally modulated self-phase-modulation-broadened pulses. In conclusion, the approach of generating self-phase-modulation-broadened pulses from pulsed laser diodes has to be modified from the initial approach explored in this thesis. The first Yb-doped chirally-coupled-core ber based systems are demonstrated and characterized in the second portion of this work. Robust single-mode performance independent of excitation or any other external mode management techniques have been demonstrated in Yb-doped chirally-coupled-core fibers. Gain and power efficiency characteristics are not compromised in any way in this novel fiber structure up to the 87W maximum power achieved. Both the small signal gain at 1064nm of 30.3dB, and the wavelength dependence of the small signal gain were comparable to currently deployed large-mode-area-fiber technology. The efficiencies of the laser and amplifier were measured to be 75% and 54

  2. Blue Pr{sup 3+}-doped ZBLAN fiber upconversion laser

    SciTech Connect

    Baney, D.M.; Rankin, G.; Chang, K.

    1996-09-01

    We demonstrate blue laser emission from a direct semiconductor laser-diode-pumped Pr{sup 3+}-doped upconversion fiber laser. This laser produced more than 1 mW of power at a wavelength of 492 nm from pump lasers operating at 830 and 1020 nm. {copyright} {ital 1996 Optical Society of America.}

  3. Characterization of laser-driven shock waves in solids using a fiber optic pressure probe

    DOE PAGESBeta

    Cranch, Geoffrey A.; Lunsford, Robert; Grun, Jacob; Weaver, James; Compton, Steve; May, Mark; Kostinski, Natalie

    2013-11-08

    Measurement of laser-driven shock wave pressure in solid blocks of polymethyl methacrylate is demonstrated using fiber optic pressure probes. Three probes based on a fiber Fabry–Perot, fiber Bragg grating, and interferometric fiber tip sensor are tested and compared. Shock waves are generated using a high-power laser focused onto a thin foil target placed in close proximity to the test blocks. The fiber Fabry–Perot sensor appears capable of resolving the shock front with a rise time of 91 ns. As a result, the peak pressure is estimated, using a separate shadowgraphy measurement, to be 3.4 GPa.

  4. Silver nanoparticle-film based saturable absorber for passively Q-switched erbium-doped fiber laser (EDFL) in ring cavity configuration

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Ruslan, N. E.; Ismail, M. A.; Ali, Z. A.; Reduan, S. A.; Lee, C. S. J.; Harun, S. W.

    2016-09-01

    We report a passive Q-switched erbium-doped fiber laser based on silver (Ag) nanoparticle thin-film saturable absorber (SA). The thin film was sandwiched between two fiber ferrules, which offer flexibility and easy integration into the ring cavity. Self-started and stable Q-switching is achieved at a central wavelength of 1558.7 nm within the C-band region. The repetition rate and pulse duration shows a typical Q-switched laser profile as we increase the pump power; the repetition rate increases from 19.471–74.074 kHz while pulse duration decreases from 8.88–3.2 µs. A signal-to-noise ratio value of 35 dB was obtained at 100 mW pump power. By using a balanced twin-detector method, the modulation depth and saturation intensity of the Ag nanoparticle thin film were measured to be 31.6% and 0.54 MW cm‑2 respectively. This result offers another alternative to the existing SA materials.

  5. Silver nanoparticle-film based saturable absorber for passively Q-switched erbium-doped fiber laser (EDFL) in ring cavity configuration

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Ruslan, N. E.; Ismail, M. A.; Ali, Z. A.; Reduan, S. A.; Lee, C. S. J.; Harun, S. W.

    2016-09-01

    We report a passive Q-switched erbium-doped fiber laser based on silver (Ag) nanoparticle thin-film saturable absorber (SA). The thin film was sandwiched between two fiber ferrules, which offer flexibility and easy integration into the ring cavity. Self-started and stable Q-switching is achieved at a central wavelength of 1558.7 nm within the C-band region. The repetition rate and pulse duration shows a typical Q-switched laser profile as we increase the pump power; the repetition rate increases from 19.471-74.074 kHz while pulse duration decreases from 8.88-3.2 µs. A signal-to-noise ratio value of 35 dB was obtained at 100 mW pump power. By using a balanced twin-detector method, the modulation depth and saturation intensity of the Ag nanoparticle thin film were measured to be 31.6% and 0.54 MW cm-2 respectively. This result offers another alternative to the existing SA materials.

  6. Bi2Te3 based passively Q-switched fiber laser with cylindrical vector beam emission.

    PubMed

    Yan, Ke; Lin, Jian; Zhou, Yong; Gu, Chun; Xu, Lixin; Wang, Anting; Yao, Peijun; Zhan, Qiwen

    2016-04-10

    We report a passively Q-switched fiber laser with cylindrical vector beam output modes using a few-mode fiber Bragg grating as a polarization-selective output coupler and Bi2Te3 as the saturable absorber. Both radially and azimuthally polarized beams can be readily generated, and the output polarization can be switchable by tuning the polarization controllers inside the laser cavity. The repetition rate of the Q-switched laser can be tuned from 31.54 to 49.40 kHz when the pump power increases from 103.5 to 139.5 mW. The fiber laser operates at a single wavelength of 1557.5 nm with a 3 dB linewidth of <0.04  nm. PMID:27139870

  7. Highly reliable and efficient 1.5μm-fiber-MOPA-based, high-power laser transmitter for space communication

    NASA Astrophysics Data System (ADS)

    Engin, Doruk; Litvinovitch, Slava; Kimpel, Frank; Puffenberger, Kent; Dang, Xung; Fouron, Jean-Luc; Martin, Nigel; Storm, Mark; Gupta, Shantanu; Utano, Rich

    2014-06-01

    Fibertek has developed a space qualifiable, highly efficient, high power (<5W), fiber based 1.5um laser optical module (LOM). The transmitter achieves 6W average and <1kW peak power out of a 2m long single mode delivery fiber with 8nsec pulses and <6Ghz linewidth. Stimulated Brillouin Scattering (SBS) is managed by precise linewidth control and by use of LMA gain fiber in the power stage while maintaining the required diffraction limited, and highly polarized (PER<20dB) output. Size and weight of the built LOM are 8"x10"x2.375" and 3 kg, respectively. With improvements in the modulation scheme and component specification, achieved LOM electrical to optical efficiency is over 17.0%. Highly efficient operation is sustained for a wide range of pulse-position modulation (16 to 128-ary PPM) formats with pulse widths varying from 8nsec to 0.5nsec and operation temperature 10-50C. Pressure stress analysis, random vibration analysis and thermal analysis of the designed LOM predicts compliance with NASA GEVS levels for vibration and thermal cycling in a vacuum environment. System will undergo both thermal vacuum and vibration testing to validate the design.

  8. Proximal fiber tip damage during Holmium:YAG and thulium fiber laser ablation of kidney stones

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2016-02-01

    The Thulium fiber laser (TFL) is being studied as an alternative to Holmium:YAG laser for lithotripsy. TFL beam originates within an 18-μm-core thulium doped silica fiber, and its near single mode, Gaussian beam profile enables transmission of higher laser power through smaller fibers than possible during Holmium laser lithotripsy. This study examines whether TFL beam profile also reduces proximal fiber tip damage compared to Holmium laser multimodal beam. TFL beam at wavelength of 1908 nm was coupled into 105-μm-core silica fibers, with 35-mJ energy, 500-μs pulse duration, and pulse rates of 50-500 Hz. For each pulse rate, 500,000 pulses were delivered. Magnified images of proximal fiber surfaces were taken before and after each trial. For comparison, 20 single-use, 270-μm-core fibers were collected after clinical Holmium laser lithotripsy procedures using standard settings (600 mJ, 350 μs, 6 Hz). Total laser energy, number of laser pulses, and laser irradiation time were recorded, and fibers were rated for damage. For TFL studies, output power was stable, and no proximal fiber damage was observed after delivery of 500,000 pulses at settings up to 35 mJ, 500 Hz, and 17.5 W average power. In contrast, confocal microscopy images of fiber tips after Holmium lithotripsy showed proximal fiber tip degradation in all 20 fibers. The proximal fiber tip of a 105-μm-core fiber transmitted 17.5 W of TFL power without degradation, compared to degradation of 270-μm-core fibers after transmission of 3.6 W of Holmium laser power. The smaller and more uniform TFL beam profile may improve fiber lifetime, and potentially reduce costs for the surgical disposables as well.

  9. A random Q-switched fiber laser.

    PubMed

    Tang, Yulong; Xu, Jianqiu

    2015-01-01

    Extensive studies have been performed on random lasers in which multiple-scattering feedback is used to generate coherent emission. Q-switching and mode-locking are well-known routes for achieving high peak power output in conventional lasers. However, in random lasers, the ubiquitous random cavities that are formed by multiple scattering inhibit energy storage, making Q-switching impossible. In this paper, widespread Rayleigh scattering arising from the intrinsic micro-scale refractive-index irregularities of fiber cores is used to form random cavities along the fiber. The Q-factor of the cavity is rapidly increased by stimulated Brillouin scattering just after the spontaneous emission is enhanced by random cavity resonances, resulting in random Q-switched pulses with high brightness and high peak power. This report is the first observation of high-brightness random Q-switched laser emission and is expected to stimulate new areas of scientific research and applications, including encryption, remote three-dimensional random imaging and the simulation of stellar lasing. PMID:25797520

  10. Thulium fiber laser damage to the ureter

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2015-07-01

    Our laboratory is studying experimental thulium fiber laser (TFL) as a potential alternative lithotripter to the clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium laser-induced damage to ureter tissue have been previously reported. Similarly, this study characterizes TFL induced ureter and stone basket damage. A TFL beam with pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rates of 150-500 Hz was delivered through a 100-μm-core, low-OH, silica optical fiber to the porcine ureter wall, in vitro. Ureter perforation times were measured and gross, histological, and optical coherence tomography images of the ablation zone were acquired. TFL operation at 150, 300, and 500 Hz produced mean ureter perforation times of 7.9, 3.8, and 1.8 s, respectively. Collateral damage averaged 510, 370, and 310 μm. TFL mean perforation time exceeded 1 s at each setting, which is a greater safety margin than previously reported during Holmium laser ureter perforation studies.

  11. Pulse dynamics in a mode-locked fiber laser and its quantum limited comb frequency uncertainty.

    PubMed

    Bao, Chengying; Funk, Andrew C; Yang, Changxi; Cundiff, Steven T

    2014-06-01

    We present an experimental study of pulse dynamics in a mode-locked Er:fiber laser. By injecting a continuous wave laser with sinusoidal intensity modulation into the fiber laser, we are able to modulate the gain. Measuring the response of the pulse energy, central frequency, central pulse time, and phase to the gain modulation allows determination of the parameters that describe their coupling. Based on the experimentally derived parameters, we evaluate the free running comb linewidth and frequency uncertainty with feedback included, assuming quantum noise is the limiting factor. Optimization of fiber lasers is also discussed.

  12. Suppression of thermal frequency noise in erbium-doped fiber random lasers.

    PubMed

    Saxena, Bhavaye; Bao, Xiaoyi; Chen, Liang

    2014-02-15

    Frequency and intensity noise are characterized for erbium-doped fiber (EDF) random lasers based on Rayleigh distributed feedback mechanism. We propose a theoretical model for the frequency noise of such random lasers using the property of random phase modulations from multiple scattering points in ultralong fibers. We find that the Rayleigh feedback suppresses the noise at higher frequencies by introducing a Lorentzian envelope over the thermal frequency noise of a long fiber cavity. The theoretical model and measured frequency noise agree quantitatively with two fitting parameters. The random laser exhibits a noise level of 6  Hz²/Hz at 2 kHz, which is lower than what is found in conventional narrow-linewidth EDF fiber lasers and nonplanar ring laser oscillators (NPROs) by a factor of 166 and 2, respectively. The frequency noise has a minimum value for an optimum length of the Rayleigh scattering fiber.

  13. Nonlinear Silicon Waveguides for Integrated Fiber Laser Systems

    NASA Astrophysics Data System (ADS)

    Wong, Chi Yan

    Silicon-on-insulator (SOI) based photonic devices have attracted great interest from photonics community because of its compatibility with state-of-the-art CMOS fabrication processes and its potential of making energy efficient and low cost photonic integrated circuits (PICs) for high bandwidth optical interconnects and integrated optical sensors. Wavelength division multiplexing (WDM) is already widely used in optical communications and is also of interest for optical sensors, providing advantages of low cost, and high speed compared with single wavelength approach. However, the cost and the bulkiness of WDM systems increase proportionally with the number of wavelengths if conventional external laser source is used. Therefore, low cost and compact laser source with stable and high line quality is of great interest for integrated sensors. In this thesis, we investigate the incorporation of silicon photonic devices as intracavity elements in fiber lasers for various applications. Therefore, the high flexibly and rich functionalities of fiber lasers can be directly used in the PIC. Also, high-speed feedback control of the cavity becomes possible. The possibility of applying nonlinear SOI waveguides to fiber lasers is investigated. We propose and demonstrate a multiwavelength erbium-doped fiber laser stabilized by four-wave mixing (FWM) in a nonlinear SOI waveguide. Such multiwavelength lasers are potentially suitable for WDM sensing. The wavelength selectivity was achieved by an intracavity Fabry-Perot comb filter. Making use of the nonlinearity of the SOI waveguide, a multiwavelength laser with six output wavelengths at 0.8 nm spacing was achieved. We study a passive mode-locked erbium-doped fiber ring laser based on a nonlinear SOI microring resonator (MRR). By using the MRR as the comb filter and the nonlinear medium, a stable mode-locked pulse train at 100 GHz was produced by filter-driven four-wave mixing. Such lasers can act as high repetition rate optical

  14. Fiber Laser Component Testing for Space Qualification Protocol Development

    NASA Astrophysics Data System (ADS)

    Falvey, S.; Buelow, M.; Nelson, B.; Starcher, Y.; Thienel, L.; Rhodes, C.; Tull, Jackson; Drape, T.; Westfall, C.

    A test protocol for the space qualifying of Ytterbium-doped diode-pumped fiber laser (DPFL) components was developed under the Bright Light effort, sponsored by AFRL/VSE. A literature search was performed and summarized in an AMOS 2005 conference paper that formed the building blocks for the development of the test protocol. The test protocol was developed from the experience of the Bright Light team, the information in the literature search, and the results of a study of the Telcordia standards. Based on this protocol developed, test procedures and acceptance criteria for a series of vibration, thermal/vacuum, and radiation exposure tests were developed for selected fiber laser components. Northrop Grumman led the effort in vibration and thermal testing of these components at the Aerospace Engineering Facility on Kirtland Air Force Base, NM. The results of the tests conducted have been evaluated. This paper discusses the vibration and thermal testing that was executed to validate the test protocol. The lessons learned will aid in future assessments and definition of space qualification protocols. Components representative of major items within a Ytterbium-doped diode-pumped fiber laser were selected for testing; including fibers, isolators, combiners, fiber Bragg gratings, and laser diodes. Selection of the components was based on guidelines to test multiple models of typical fiber laser components. A goal of the effort was to test two models (i.e. different manufacturers) of each type of article selected, representing different technologies for the same type of device. The test articles did not include subsystems or systems. These components and parts may not be available commercial-off-the-shelf (COTS), and, in fact, many are custom articles, or newly developed by the manufacturer. The primary goal for this effort is a completed taxonomy that lists all relevant laser components, modules, subsystems, and interfaces, and cites the documentation for space

  15. Experimental study of the SLM behavior and remote sensing applications of a multi-wavelength fiber laser topology based on DWDMs

    NASA Astrophysics Data System (ADS)

    Leandro, Daniel; Perez-Herrera, Rosa Ana; Iturri, Ion; Lopez-Amo, Manuel

    2015-03-01

    In this work, two different multi-wavelength fiber ring laser configurations have been proposed and experimentally demonstrated. The aim of this paper is to show the versatility of the MUX/DMUX device for designing fiber lasers. That was carried out by enhancing the performance of two intrinsically different fiber lasers: an EDF in single longitudinal-mode (SLM) operation and an ultra-long cavity multi-wavelength Raman laser for remote sensing applications. The main objective of the first experimental setup is to generate SLM emission lines with linewidths as narrow as possible. That was carried out by using the interaction between the reflected signals from the FBGs and the transmitted signal from the corresponding PS-FBG in each transmission band. The second topology consists of a multi-wavelength fiber laser for remote sensing applications by using Raman amplification where sensors located 100 km away from the receiver have been measured. As a remarkable improvement from other remote sensing systems, the sensors can be located at any place of the fiber length and can be monitored simultaneously.

  16. Industrial fiber beam delivery system for ultrafast lasers: applications and recent advances

    NASA Astrophysics Data System (ADS)

    Eilzer, Sebastian; Funck, Max C.; Wedel, Björn

    2016-03-01

    Fiber based laser beam delivery is the method of choice for high power laser applications whenever great flexibility is required. For cw-lasers fiber beam delivery has long been established but has recently also become available for ultrafast lasers. Using micro-structured hollow core fibers that guide the laser beam mostly inside a hollow core, nonlinear effects and catastrophic damage that arise in conventional glass fibers can be avoided. Today, ultrafast pulses with several 100 μJ and hundreds of MW can be transmitted in quasi single mode fashion. In addition, the technology opens new possibilities for beam delivery systems as the pulse propagation inside the fiber can be altered on purpose. For example to shorten the pulse duration of picosecond lasers down into the femtosecond regime. We present a modular fiber beam delivery system for micromachining applications with industrial pico- and femtosecond lasers that is flexibly integrated into existing applications. Micro-structured hollow core fibers inside the sealed laser light cable efficiently guide high-power laser pulses over distances of several meters with excellent beam quality, while power, pulse duration and polarization are maintained. Robust and stable beam transport during dynamic operation as in robot or gantry systems will be discussed together with optional pulse compression.

  17. Microfiber-based few-layer MoS2 saturable absorber for 2.5 GHz passively harmonic mode-locked fiber laser.

    PubMed

    Liu, Meng; Zheng, Xu-Wu; Qi, You-Li; Liu, Hao; Luo, Ai-Ping; Luo, Zhi-Chao; Xu, Wen-Cheng; Zhao, Chu-Jun; Zhang, Han

    2014-09-22

    We reported on the generation of high-order harmonic mode-locking in a fiber laser using a microfiber-based molybdenum disulfide (MoS(2)) saturable absorber (SA). Taking advantage of both the saturable absorption and large third-order nonlinear susceptibilities of the few-layer MoS(2), up to 2.5 GHz repetition rate HML pulse could be obtained at a pump power of 181 mW, corresponding to 369th harmonic of fundamental repetition frequency. The results provide the first demonstration of the simultaneous applications of both highly nonlinear and saturable absorption effects of the MoS(2), indicating that the microfiber-based MoS(2) photonic device could serve as high-performance SA and highly nonlinear optical component for application fields such as ultrafast nonlinear optics.

  18. Prototype fiber Bragg Grattings (FBG) sensor based on intensity modulation of the laser diode low frequency vibrations measurement

    NASA Astrophysics Data System (ADS)

    Setiono, Andi; Ula, Rini Khamimatul; Hanto, Dwi; Widiyatmoko, Bambang; Purnamaningsih, Retno Wigajatri

    2016-02-01

    In general, Fiber Bragg Grating (FBG) sensor works based on observation of spectral response characteristic to detect the desired parameter. In this research, we studied intensity response characteristic of FBG to detect the dynamic strain. Experiment result show that the reflected intensity had linier relationships with dynamic strain. Based on these characteristics, we developed the FBG sensor to detect low frequency vibration. This sensor is designed by attaching the FBG on the bronze cantilever with dimensions of 85×3×0.5 mm. Measurement results showed that the sensor was able to detect vibrations in the frequency range of 7-10 Hz at temperature range of 25-45 ˚C. The measured frequency range is still within the frequency range of digging activity, therefore this vibration sensor can be applied for oil pipelines vandalisation detection system.

  19. Multichannel fiber-based diffuse reflectance spectroscopy for the rat brain exposed to a laser-induced shock wave: comparison between ipsi- and contralateral hemispheres

    NASA Astrophysics Data System (ADS)

    Miyaki, Mai; Kawauchi, Satoko; Okuda, Wataru; Nawashiro, Hiroshi; Takemura, Toshiya; Sato, Shunichi; Nishidate, Izumi

    2015-03-01

    Due to considerable increase in the terrorism using explosive devices, blast-induced traumatic brain injury (bTBI) receives much attention worldwide. However, little is known about the pathology and mechanism of bTBI. In our previous study, we found that cortical spreading depolarization (CSD) occurred in the hemisphere exposed to a laser- induced shock wave (LISW), which was followed by long-lasting hypoxemia-oligemia. However, there is no information on the events occurred in the contralateral hemisphere. In this study, we performed multichannel fiber-based diffuse reflectance spectroscopy for the rat brain exposed to an LISW and compared the results for the ipsilateral and contralateral hemispheres. A pair of optical fibers was put on the both exposed right and left parietal bone; white light was delivered to the brain through source fibers and diffuse reflectance signals were collected with detection fibers for both hemispheres. An LISW was applied to the left (ipsilateral) hemisphere. By analyzing reflectance signals, we evaluated occurrence of CSD, blood volume and oxygen saturation for both hemispheres. In the ipsilateral hemispheres, we observed the occurrence of CSD and long-lasting hypoxemia-oligemia in all rats examined (n=8), as observed in our previous study. In the contralateral hemisphere, on the other hand, no occurrence of CSD was observed, but we observed oligemia in 7 of 8 rats and hypoxemia in 1 of 8 rats, suggesting a mechanism to cause hypoxemia or oligemia or both that is (are) not directly associated with CSD in the contralateral hemisphere.

  20. Constant peak-power single-frequency linearly-polarized all-fiber laser for coherent detection based on closed-loop feedback technology

    NASA Astrophysics Data System (ADS)

    Ding, Yaqian; Zhang, Xiang; Li, Dong; Wang, Dapeng; Zhang, Renzhong; Song, Chengying; Che, Haozhao; Wang, Rui; Guo, Baoling; Chen, Guanghui

    2015-10-01

    In this paper, a practical single-frequency high-repetition linearly-polarized eye-safe all-fiber laser with constant peak power is demonstrated. It is based on master-oscillator power amplifier (MOPA) system. A distributed feedback laser diode simulating at 1550nm with narrow linewidth of 2.3 kHz is employed as the seed source. It is modulated to a pulse laser with high repetition of 20 kHz and peak power of 10mW by an acousto-optic modulator (AOM). The pulse width is tunable between 100ns to 400ns. Two-stage cascade amplifier is established, which consists of a pre-amplifier and a power-amplifier. Amplified spontaneous emission (ASE) and stimulated billion scattering are well suppressed by special management. The output peak power of 30W is obtained, which has nearly diffraction-limited beam quality. It operates in linewidth of 1.2MHz, polarization-extinction ratio (PER) of 25dB and signal-to-noise ratio (SNR) of more than 40dB. Gain of the whole amplifier achieves nearly 35dB. Furthermore, an embedded control system (ECS) based on the WinCE operating system (OS) and the chip of S3C2440 is proposed. This control system based on closed-loop feedback technology makes the peak power keeping constant even the pulse width tunable, which is convenient for the end user of the radar. This robust portable laser is remarkable and fulfills the desire of coherent detection excellently.

  1. High Energy, Narrow Linewidth 1572nm Eryb-Fiber Based MOPA for a Multi-Aperture CO2 Trace-Gas Laser Space Transmitter

    NASA Technical Reports Server (NTRS)

    Engin, Doruk; Mathason, Brian; Stephen, Mark; Yu, Anthony; Cao, He; Fouron, Jean-Luc; Storm, Mark

    2016-01-01

    Accurate global measurements of tropospheric CO2 mixing ratios are needed to study CO2 emissions and CO2 exchange with the land and oceans. NASA Goddard Space Flight Center (GSFC) is developing a pulsed lidar approach for an integrated path differential absorption (IPDA) lidar to allow global measurements of atmospheric CO2 column densities from space. Our group has developed, and successfully flown, an airborne pulsed lidar instrument that uses two tunable pulsed laser transmitters allowing simultaneous measurement of a single CO2 absorption line in the 1570 nm band, absorption of an O2 line pair in the oxygen A-band (765 nm), range, and atmospheric backscatter profiles in the same path. Both lasers are pulsed at 10 kHz, and the two absorption line regions are sampled at typically a 300 Hz rate. A space-based version of this lidar must have a much larger lidar power-area product due to the x40 longer range and faster along track velocity compared to airborne instrument. Initial link budget analysis indicated that for a 400 km orbit, a 1.5 m diameter telescope and a 10 second integration time, a 2 mJ laser energy is required to attain the precision needed for each measurement. To meet this energy requirement, we have pursued parallel power scaling efforts to enable space-based lidar measurement of CO2 concentrations. These included a multiple aperture approach consists of multi-element large mode area fiber amplifiers and a single-aperture approach consists of a multi-pass Er:Yb:Phosphate glass based planar waveguide amplifier (PWA). In this paper we will present our laser amplifier design approaches and preliminary results.

  2. Property and Shape Modulation of Carbon Fibers Using Lasers.

    PubMed

    Blaker, Jonny J; Anthony, David B; Tang, Guang; Shamsuddin, Siti-Ros; Kalinka, Gerhard; Weinrich, Malte; Abdolvand, Amin; Shaffer, Milo S P; Bismarck, Alexander

    2016-06-29

    An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes. PMID:27227575

  3. Property and Shape Modulation of Carbon Fibers Using Lasers.

    PubMed

    Blaker, Jonny J; Anthony, David B; Tang, Guang; Shamsuddin, Siti-Ros; Kalinka, Gerhard; Weinrich, Malte; Abdolvand, Amin; Shaffer, Milo S P; Bismarck, Alexander

    2016-06-29

    An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes.

  4. Towards ten-watt-level 3-5 µm Raman lasers using tellurite fiber.

    PubMed

    Zhu, Gongwen; Geng, Lixiang; Zhu, Xiushan; Li, Li; Chen, Qian; Norwood, R A; Manzur, T; Peyghambarian, N

    2015-03-23

    Raman lasers based on mid-infrared fibers operating at 3-5 µm atmospheric transparency window are attractive sources for several applications. Compared to fluoride and chalcogenide fibers, tellurite fibers are more advantageous for high power Raman fiber laser sources at 3-5 µm because of their broader Raman gain bandwidth, much larger Raman shift and better physical and chemical properties. Here we report on our simulations for the development of 10-watt-level 3-5 µm Raman lasers using tellurite fibers as the nonlinear gain medium and readily available continuous-wave (cw) and Q-switched erbium-doped fluoride fiber lasers at 2.8 µm as the pump sources. Our results show that a watt-level or even ten-watt-level fiber laser source in the 3-5 µm atmospheric transparency window can be achieved by utilizing the 1st- and 2nd-order Raman scattering in the tellurite fiber. The presented numerical study provides valuable guidance for future 3-5 um Raman fiber laser development. PMID:25837094

  5. Single-frequency gain-switched Ho-doped fiber laser.

    PubMed

    Geng, Jihong; Wang, Qing; Luo, Tao; Case, Bryson; Jiang, Shibin; Amzajerdian, Farzin; Yu, Jirong

    2012-09-15

    We demonstrate a single-frequency gain-switched Ho-doped fiber laser based on heavily doped silicate glass fiber fabricated in-house. A Q-switched Tm-doped fiber laser at 1.95 μm was used to gain-switch the Ho-doped fiber laser via in-band pumping. Output power of the single-frequency gain-switched pulses has been amplified in a cladding-pumped Tm-Ho-codoped fiber amplifier with 1.2 m active fiber pumped at 803 nm. Two different nonlinear effects, i.e., modulation instability and stimulated Brillouin scattering, could be seen in the 10 μm-core fiber amplifier when the peak power exceeds 3 kW. The single-frequency gain-switched fiber laser was operated at 2.05 μm, a popular laser wavelength for Doppler lidar application. This is the first demonstration of this kind of fiber laser.

  6. A review of Thulium fiber laser ablation of kidney stones

    NASA Astrophysics Data System (ADS)

    Fried, Nathaniel M.; Blackmon, Richard L.; Irby, Pierce B.

    2011-02-01

    The clinical solid-state Holmium:YAG laser lithotripter (λ=2120 nm) is capable of operating at high pulse energies, but its efficient operation is limited to low pulse rates during lithotripsy. The diode-pumped experimental Thulium Fiber Laser (λ=1908 nm) is limited to low pulse energies, but can operate at high pulse rates. This review compares stone ablation threshold, ablation rate, and retropulsion effects for Ho:YAG and TFL. Laser lithotripsy complications also include optical fiber bending failure resulting in endoscope damage and low irrigation rates leading to poor visibility. Both problems are related to fiber diameter and limited by Ho:YAG laser multimode spatial beam profile. This study exploits TFL spatial beam profile for higher power transmission through smaller fibers. A short taper is also studied for expanding TFL beam at the distal tip of a small-core fiber. Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, irrigation rates, and deflection through a flexible ureteroscope were measured for tapered fiber and compared with conventional fibers. The stone ablation threshold for TFL was four times lower than for Ho:YAG. Stone retropulsion with Ho:YAG increased linearly with pulse energy. Retropulsion with TFL was minimal at pulse rates < 150 Hz, then rapidly increased at higher pulse rates. TFL beam profile provides higher laser power through smaller fibers than Ho:YAG laser, potentially reducing fiber failure and endoscope damage and allowing greater irrigation rates for improved visibility and safety. Use of a short tapered distal fiber tip also allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional fibers, without compromising fiber bending, stone ablation efficiency, or irrigation rates.

  7. Dynamic fiber Bragg grating strain sensor using a wavelength-locked tunable fiber ring laser

    NASA Astrophysics Data System (ADS)

    Zhu, Yinian; Krishnaswamy, Sridhar

    2012-04-01

    The interrogation systems based on fiber-optic sensors are very attractive for the practical applications in structural health monitoring owing to a number of advantages of optical fiber elements over their electronic counterparts. Among the fiber-optic sensors, the fiber Bragg gratings (FBGs) have their own unique features to be widely used for detection of acoustic emission. We have developed a dynamic strain sensing system by using a tunable single longitudinal mode Erbium-doped fiber ring laser to be locked to the middle-reflection wavelength of the FBG as the demodulation technique. A proportional-integral-derivative device continuously controls the laser wavelength that is kept at the FBG middle-reflection wavelength, thus stabilizing the operating point against quasi-static perturbation, while the high frequency dynamic strain shifts the FBG reflection profile. The reflected power varies in proportion to the applied strain which can be derived directly from AC photocurrent of the reflected signal. We have designed and assembled a fourchannel demodulator system for simultaneous high frequency dynamic strain sensing.

  8. Switchable and tunable erbium-doped fiber lasers using a hollow-core Bragg fiber

    NASA Astrophysics Data System (ADS)

    Zhao, Tanglin; Lian, Zhenggang; Wang, Xin; Shen, Yan; Lou, Shuqin

    2016-11-01

    A switchable and tunable erbium-doped fiber laser (EDFL) is proposed and experimentally demonstrated in this paper. A novel comb filter, which consists of a section of hollow-core Bragg fiber cascaded with Sagnac loop based on a polarization-maintaining fiber (PMF), is developed to suppress the mode competition in the EDFL. By carefully adjusting the polarization controllers, switchable and tunable single- or dual-wavelength lasing outputs with side-mode suppression ratios as high as 50 dB can be achieved. Single-wavelength lasing outputs with a 3 dB linewidth of 0.02 nm can be tuned within the wavelength range from 1562.4 nm to 1565.8 nm. Two kinds of dual-wavelength lasing outputs with different wavelength intervals of 1 nm and 2.1 nm can be obtained and the corresponding tunable wavelength range is 0.5 nm. Moreover, the wavelength shift and peak power fluctuation of both the single- and dual-wavelength lasing outputs are less than 0.1 nm and 2 dB over half an hour at room temperature, which indicates that the proposed fiber laser has good stability. To the best of our knowledge, it is the first time that a hollow-core Bragg fiber has been used as a comb filter in the EDFL.

  9. DFG-based mid-IR generation using a compact dual-wavelength all-fiber amplifier for laser spectroscopy applications.

    PubMed

    Krzempek, Karol; Sobon, Grzegorz; Abramski, Krzysztof M

    2013-08-26

    We demonstrate a compact mid-infrared (mid-IR) radiation source based on difference frequency generation (DFG) in periodically poled lithium niobate (PPLN) crystal. The system incorporates a dual-wavelength master oscillator power amplifier (MOPA) source capable of simultaneous amplification of 1064 nm and 1548 nm signals in a common active fiber co-doped with erbium and ytterbium ions. Two low-power seed lasers were amplified by a factor of 14.4 dB and 23.7 dB for 1064 nm and 1548 nm, respectively and used in a nonlinear DFG setup to generate 1.14 mW of radiation centered at 3.4 μm. The system allowed for open-path detection of methane (CH(4)) in ambient air with estimated minimum detectable concentration at a level of 26 ppbv. PMID:24105549

  10. Development of a flow injection analysis (FIA) system for the measurement of heavy metals using a fiber optic chemical sensor based on laser-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Zhang, Jingdong; Prestel, Harald; Gahr, Achim; Niessner, Reinhard

    2000-05-01

    The development of a fiber optic sensor system is described, for the on-line detection of heavy metal ions in water. This is based on laser-induced fluorescence spectroscopy of suitable metal-ligand complexes. The sensor system is designed to measure heavy metal ions in the field. Flow injection analysis (FIA) is coupled with the sensor system, to overcome problems of a slow diffusion rate of heavy metals through the membrane of an in situ sensor head. Preliminary experiments show the new FIA system has good reproducibility, a high sample analysis rate and it can measure heavy metal ions (Cu(II), Ni(II), Cd(II) and Zn(II)) at the ppb level, when using the appropriate ligands.

  11. All-fiber supercontinuum source based on a mode-locked ytterbium laser with dispersion compensation by linearly chirped Bragg grating.

    PubMed

    Kivistö, S; Herda, R; Okhotnikov, O G

    2008-01-01

    We demonstrate an all-fiber picosecond soliton laser with dispersion management performed by a chirped Bragg grating that generates ~1.6 ps pulses representing the shortest pulsewidth reported to date using this technology. The large anomalous dispersion provided by the grating allows building of a long-length cavity laser with an extremely low fundamental repetition rate of 2.6 MHz. This source allows us to use an original approach for producing energetic pulses that after boosting in a medium power core-pumped amplifier produce an octave-spanning supercontinuum radiation in a nonlinear photonic crystal fiber.

  12. Passively mode-locked fiber laser by using monolayer chemical vapor deposition of graphene on D-shaped fiber.

    PubMed

    Chen, Tao; Liao, Changrui; Wang, D N; Wang, Yiping

    2014-05-01

    We demonstrate a monolayer graphene saturable absorber (SA) based on D-shaped fiber for operation of the mode-locked fiber laser. The monolayer graphene is grown by chemical vapor deposition (CVD) on Cu substrate and transferred onto the polymer, and then covered with D-shaped fiber, which allows light-graphene interaction via the evanescent field of the fiber. Due to the side-coupled interaction, the length of graphene is long enough to avoid optical power-induced thermal damage. Using such a graphene-based SA, stable mode-locked solitons with 4.5 nm spectral bandwidth and 713 fs pulsewidth at the 1563 nm wavelength have been obtained under 280 mW pump power. The influence of total cavity dispersion on the optical spectrum and pulse is also investigated by adding different lengths of single-mode fiber in the laser cavity.

  13. Femtosecond fiber laser welding of dissimilar metals.

    PubMed

    Huang, Huan; Yang, Lih-Mei; Bai, Shuang; Liu, Jian

    2014-10-01

    In this paper, welding of dissimilar metals was demonstrated for the first time, to the best of our knowledge, by using a high-energy high-repetition-rate femtosecond fiber laser. Metallurgical and mechanical properties were investigated and analyzed under various processing parameters (pulse energy, repetition rate, and welding speed). Results showed that the formation of intermetallic brittle phases and welding defects could be effectively reduced. Strong welding quality with more than 210 MPa tensile strength for stainless steel-aluminum and 175 MPa tensile strength for stainless steel-magnesium has been demonstrated. A minimal heat affected zone and uniform and homogenous phase transformation in the welding region have been demonstrated. This laser-welding technique can be extended for various applications in semiconductor, automobile, aerospace, and biomedical industries.

  14. Tm:germanate Fiber Laser for Planetary Water Vapor Atmospheric Profiling

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; De Young, Russell

    2009-01-01

    The atmospheric profiling of water vapor is necessary for finding life on Mars and weather on Earth. The design and performance of a water vapor lidar based on a Tm:germanate fiber laser is presented.

  15. A Master-Oscillator-Power-Amplifier 2-micron Laser Using Fiber Phase-conjugate Mirror

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Bai, Yingxin; Shkunov, V.; Rockwell, D.; Betin, A.; Wang, J.; Petros, M.; Petzar, Paul; Trieu, Bo

    2007-01-01

    For the first time, a 2-micron master-oscillator-power-amplifier laser using a fiber based phase conjugation mirror has been demonstrated. The beam quality improvement and 56% of the PCM reflectivity have been achieved.

  16. Growing Crystaline Sapphire Fibers By Laser Heated Pedestal Techiques

    DOEpatents

    Phomsakha, Vongvilay; Chang, Robert S. F.; Djeu, Nicholas I.

    1997-03-04

    An improved system and process for growing crystal fibers comprising a means for creating a laser beam having a substantially constant intensity profile through its cross sectional area, means for directing the laser beam at a portion of solid feed material located within a fiber growth chamber to form molten feed material, means to support a seed fiber above the molten feed material, means to translate the seed fiber towards and away from the molten feed material so that the seed fiber can make contact with the molten feed material, fuse to the molten feed material and then be withdrawn away from the molten feed material whereby the molten feed material is drawn off in the form of a crystal fiber. The means for creating a laser beam having a substantially constant intensity profile through its cross sectional area includes transforming a previously generated laser beam having a conventional gaussian intensity profile through its cross sectional area into a laser beam having a substantially constant intensity profile through its cross sectional area by passing the previously generated laser beam through a graded reflectivity mirror. The means for directing the laser beam at a portion of solid feed material is configured to direct the laser beam at a target zone which contains the molten feed material and a portion of crystal fiber drawn off the molten feed material by the seed fiber. The means to support the seed fiber above the molten feed material is positioned at a predetermined height above the molten feed material. This predetermined height provides the seed fiber with sufficient length and sufficient resiliency so that surface tension in the molten feed material can move the seed fiber to the center of the molten feed material irrespective of where the seed fiber makes contact with the molten feed material. The internal atmosphere of the fiber growth chamber is composed substantially of Helium gas.

  17. CW single transverse mode all-fiber Tm3+-doped silica fiber laser

    NASA Astrophysics Data System (ADS)

    Song, E. Z.; Li, W. H.; You, L.

    2012-04-01

    The CW 25.6 W output power with a slope efficiency of 30.6% respected to the pump power from a CW single transverse mode all-fiber Tm3+-doped Silica Fiber Laser is reported. The all-fiber laser is made up by progressively splicing the pigtail fiber, matched FBG fiber and Tm fiber. The reflective FBG and Tm3+-doped fiber end Fresnel reflection build up the laser resonance cavity. Due to the multi-mode FBG as the reflective mirror, the output laser spectrum is multi-peaks at high output power, but the spectrum width is less than 2 nm at 1.94 μm. We estimate the beam quality to be M 2 = 2.39, clearly indicating nearly diffraction-limited beam propagation.

  18. Wireless fiber laser sensor combining photonic generation beat frequency demodulation technology

    NASA Astrophysics Data System (ADS)

    Liu, Shengchun; Gu, Rong; Yu, Xiujuan; Yin, Zuowei; Chen, Xiangfei

    2011-12-01

    A simple wireless-fiber laser sensor is proposed base on directly photonic generation of microwave beat signal. In this scheme, a multi-longitudinal modes fiber laser is formed by two fiber Bragg gratings and a section of erbium-doped fiber. Two same 2G-GSM mobile antennas are used as wireless transmitter and receiver. By this method, the real-time monitoring of fiber laser sensors can be achieved through over ultra-long distance. This technique offers a simple, all-electrical and cheap way for fiber sensor information accessing wireless net. The experiment result shows the root mean square deviations of the sensor are about 4.7 μɛ and 6.7 μɛ at 2.38 GHz before and after wireless transmission, respectively.

  19. Design of highly doped Yb3+ fiber ring laser

    NASA Astrophysics Data System (ADS)

    Huang, Xiu-jiang; Liu, Yong-zhi; Sui, Zhan; Li, Ming-zhong; Lin, Hong-huan; Wang, Jian-jun; Zhao, De-shuang; Wang, Feng-rui; Chen, Ji-xin

    2005-01-01

    Ytterbium-doped silica fibers exhibit very broad absorption and emission bands, from 800nm to 1064nm for absorption and 970nm to 1200nm for emission. Therefore wide band lasers can be obtained using a wide variety of pump lasers. In this paper, the characteristics of high-doped Yb3+ fiber are analyzed and verified by experiment and a highly-doped Yb3+ fiber ring laser with short cavity has been presented. Comparing with normal Yb3+doped fiber, the relationship between the important characteristics of the Yb3+doped fiber laser such as threshold power, output power and laser parameters such as pump power, fiber length, output couple ratio is analyzed. Numerical results are coincident with the experiment phenomenon very well. A 1053 nm pulse has been achieved in our fiber laser. The output power is 6mW as pump power is 110mW and the slope efficiency is 17%. The Yb3+ fiber laser we produced can be used as a stable source in obtaining ultrafast pulse, fiber sense and optical communications.

  20. Active Q-switching of a fiber laser using a modulated fiber Fabry-Perot filter and a fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Martínez Manuel, Rodolfo; Kaboko, J. J. M.; Shlyagin, M. G.

    2016-02-01

    We propose and demonstrate a simple and robust actively Q-switched erbium-doped fiber ring cavity laser. The Q-switching is based on dynamic spectral overlapping of two filters, namely a fiber Bragg grating-based filter and a fiber Fabry-Perot tunable filter. Using 3.5 m of erbium-doped fiber and a pump power of only 60 mW, Q-switched pulses with a peak power of 9.7 W and a pulse duration of 500 ns were obtained. A pulse repetition rate can be continuously varied from a single shot to a few KHz.

  1. Profiling atmospheric water vapor using a fiber laser lidar system.

    PubMed

    De Young, Russell J; Barnes, Norman P

    2010-02-01

    A compact, lightweight, and efficient fiber laser lidar system has been developed to measure water vapor profiles in the lower atmosphere of Earth or Mars. The line narrowed laser consist of a Tm:germanate fiber pumped by two 792 nm diode arrays. The fiber laser transmits approximately 0.5 mJ Q- switched pulses at 5 Hz and can be tuned to water vapor lines near 1.94 microm with linewidth of approximately 20 pm. A lightweight lidar receiver telescope was constructed of carbon epoxy fiber with a 30 cm Fresnel lens and an advanced HgCdTe APD detector. This system has made preliminary atmospheric measurements.

  2. High energy, narrow linewidth 1572nm ErYb-fiber based MOPA for a multi-aperture CO2 trace-gas laser space transmitter

    NASA Astrophysics Data System (ADS)

    Engin, Doruk; Mathason, Brian; Stephen, Mark; Yu, Anthony; Cao, He; Fouron, Jean-Luc; Storm, Mark

    2016-03-01

    A cladding-pumped, LMA ErYb fiber-based, amplifier is presented for use in a LIDAR transmitter for remote sensing of atmospheric CO2 from space. The amplifier is optimized for high peak power, high efficiency, and narrow linewidth operation at 1572.3nm. Using highly reliable COTS components, the amplifier achieves 0.5kW peak power (440uJ pulse energy), 3.3W average power with transform limited (TL) linewidth and M2<1.3. The power amplifier supports a 30% increase in pulse energy when linewidth is increased to 100MHz. A preliminary conductively cooled laser optical module (LOM) concept has size 9x10x1.25 in (113 in3) and estimated weight of 7.2lb (3.2 kg). Energy scaling with pulse width up to 645uJ, 1.5usec is demonstrated. A novel doubleclad ErYb LMA fiber (30/250um) with high pump absorption (6 dB/m at 915nm) was designed, fabricated, and characterized for power scaling. The upgraded power amplifier achieves 0.8kW peak power (720uJ pulse energy) 5.4W average power with TL linewidth and M2<1.5.

  3. Delivering dispersion-managed soliton and Q-switched pulse in fiber laser based on graphene and nonlinear optical loop mirror

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Wang, F.; Yu, Q.; Zhang, X.; Lu, Y. X.; Gu, J.

    2016-11-01

    We propose and experimentally demonstrate a bidirectional erbium-doped fiber laser delivering dispersion-managed soliton (DMS) and Q-switched pulse based on a graphene-polyvinyl alcohol (PVA) and nonlinear optical loop mirror (NOLM) saturable absorbers (SAs). In proposed structure, the DMS is achieved in clockwise (CW) direction and Q-switched pulse is obtained in counter-clockwise (CCW) direction. By properly adjusting the intracavity attenuators (ATT) and polarizer controllers (PCs), DMS in the CW direction and Q-switched pulse in the CCW direction can be obtained, respectively or simultaneously. The DMS with full width at half maximum (FWHM) of ~480 fs, signal to noise ratio (SNR) of ~60 dB and repetition frequency about 3.907 MHz is obtained. The Q-switched pulse is established at a pump power of 180 mW with a repetition rate of ~43.5 kHz and FWHM of ~8.18 μs. When the pump power is increased to 700 mW, Q-switched pulse with a repetition rate of ~107.1 kHz and FWHM of ~2.15 μs is generated. When the two type pulses are formed simultaneously, the maximum repetition rate of Q-switched pulse is 55.8 kHz and minimum FWHM is 2.81 μs, the DMS can be formed by properly adjusting PC and ATT in this case. To the best of our knowledge, it is the first time that Q-switched pulse and DMS have been acquired respectively or simultaneously in a fiber laser.

  4. 150 W highly-efficient Raman fiber laser.

    PubMed

    Feng, Yan; Taylor, Luke R; Calia, Domenico Bonaccini

    2009-12-21

    We report a more than 150 W spectrally-clean continuous wave Raman fiber laser at 1120 nm with an optical efficiency of 85%. A approximately 30 m standard single mode silica fiber is used as Raman gain fiber to avoid second Stokes emission. A spectrally asymmetric resonator (in the sense of mirror reflection bandwidth) with usual fiber Bragg gratings is designed to minimize the laser power lost into the unwanted direction, even when the effective reflectivity of the rear fiber Bragg grating becomes as low as 81.5%. PMID:20052078

  5. 150 W highly-efficient Raman fiber laser.

    PubMed

    Feng, Yan; Taylor, Luke R; Calia, Domenico Bonaccini

    2009-12-21

    We report a more than 150 W spectrally-clean continuous wave Raman fiber laser at 1120 nm with an optical efficiency of 85%. A approximately 30 m standard single mode silica fiber is used as Raman gain fiber to avoid second Stokes emission. A spectrally asymmetric resonator (in the sense of mirror reflection bandwidth) with usual fiber Bragg gratings is designed to minimize the laser power lost into the unwanted direction, even when the effective reflectivity of the rear fiber Bragg grating becomes as low as 81.5%.

  6. High-power ns-pulse fiber laser sources for remote sensors

    NASA Astrophysics Data System (ADS)

    Di Teodoro, Fabio; Belden, Paul; Ionov, Pavel; Werner, Nicolette

    2014-12-01

    The development of fiber-based laser sources for space-borne remote sensors must meet many concurrent requirements including high pulse energy/peak power, excellent beam quality, narrow spectral linewidth, simple thermal management, small volume and mass, low power consumption, rugged packaging, and long-term reliability. To address these requirements, many aspects of pulse fiber laser technology must be advanced beyond the state of the art of traditional optical sources used in telecommunications and materials processing. In this article, we discuss component and solutions that enable pulsed fiber laser sources to support remote sensing from space. We also describe several examples of such sources and characterize their performance.

  7. Flexible high-repetition-rate ultrafast fiber laser

    PubMed Central

    Mao, Dong; Liu, Xueming; Sun, Zhipei; Lu, Hua; Han, Dongdong; Wang, Guoxi; Wang, Fengqiu

    2013-01-01

    High-repetition-rate pulses have widespread applications in the fields of fiber communications, frequency comb, and optical sensing. Here, we have demonstrated high-repetition-rate ultrashort pulses in an all-fiber laser by exploiting an intracavity Mach-Zehnder interferometer (MZI) as a comb filter. The repetition rate of the laser can be tuned flexibly from about 7 to 1100 GHz by controlling the optical path difference between the two arms of the MZI. The pulse duration can be reduced continuously from about 10.1 to 0.55 ps with the spectral width tunable from about 0.35 to 5.7 nm by manipulating the intracavity polarization controller. Numerical simulations well confirm the experimental observations and show that filter-driven four-wave mixing effect, induced by the MZI, is the main mechanism that governs the formation of the high-repetition-rate pulses. This all-fiber-based laser is a simple and low-cost source for various applications where high-repetition-rate pulses are necessary. PMID:24226153

  8. High performance distributed feedback fiber laser sensor array system

    NASA Astrophysics Data System (ADS)

    He, Jun; Li, Fang; Xu, Tuanwei; Wang, Yan; Liu, Yuliang

    2009-11-01

    Distributed feedback (DFB) fiber lasers have their unique properties useful for sensing applications. This paper presents a high performance distributed feedback (DFB) fiber laser sensor array system. Four key techniques have been adopted to set up the system, including DFB fiber laser design and fabrication, interferometric wavelength shift demodulation, digital phase generated carrier (PGC) technique and dense wavelength division multiplexing (DWDM). Experimental results confirm that a high dynamic strain resolution of 305 fɛ/√Hz (@ 1 kHz) has been achieved by the proposed sensor array system. And the multiplexing of eight channel DFB fiber laser sensor array has been demonstrated. The proposed DFB fiber laser sensor array system is suitable for ultra-weak signal detection, and has potential applications in the field of petroleum seismic explorations, earthquake prediction, and security.

  9. Tutorial on fiber-based sources for biophotonic applications

    NASA Astrophysics Data System (ADS)

    Taylor, James R.

    2016-06-01

    Fiber-based lasers and master oscillator power fiber amplifier configurations are described. These allow spectral versatility coupled with pulse width and pulse repetition rate selection in compact and efficient packages. This is enhanced through the use of nonlinear optical conversion in fibers and fiber-coupled nonlinear crystals, which can be integrated to provide all-fiber pump sources for diverse application. The advantages and disadvantages of sources based upon supercontinuum generation, stimulated Raman conversion, four-wave mixing, parametric generation and difference frequency generation, allowing spectral coverage from the UV to the mid-infrared, are considered.

  10. Nanosecond square pulse generation in fiber lasers with normal dispersion

    NASA Astrophysics Data System (ADS)

    Zhao, L. M.; Tang, D. Y.; Cheng, T. H.; Lu, C.

    2007-04-01

    We report on the generation of nanosecond square pulses in a passively mode-locked fiber ring laser made of purely normal dispersive fibers. Different to the noise-like pulse operation of the laser, the generated square pulses are stable and have no internal structures. We show that the formation of the square pulse is due to the combined action of the pulse peak clamping effect caused by the cavity and the almost linear pulse propagation in the normal dispersive fibers.

  11. 280  GHz dark soliton fiber laser.

    PubMed

    Song, Y F; Guo, J; Zhao, L M; Shen, D Y; Tang, D Y

    2014-06-15

    We report on an ultrahigh repetition rate dark soliton fiber laser. We show both numerically and experimentally that by taking advantage of the cavity self-induced modulation instability and the dark soliton formation in a net normal dispersion cavity fiber laser, stable ultrahigh repetition rate dark soliton trains can be formed in a dispersion-managed cavity fiber laser. Stable dark soliton trains with a repetition rate as high as ∼280  GHz have been generated in our experiment. Numerical simulations have shown that the effective gain bandwidth limitation plays an important role on the stabilization of the formed dark solitons in the laser.

  12. Dark pulse generation in fiber lasers incorporating carbon nanotubes.

    PubMed

    Liu, H H; Chow, K K

    2014-12-01

    We demonstrate the generation of dark pulses from carbon nanotube (CNT) incorporated erbium-doped fiber ring lasers with net anomalous dispersion. A side-polished fiber coated with CNT layer by optically-driven deposition method is embedded into the laser in order to enhance the birefringence and nonlinearity of the laser cavity. The dual-wavelength domain-wall dark pulses are obtained from the developed CNT-incorporated fiber laser at a relatively low pump threshold of 50.6 mW. Dark pulses repeated at the fifth-order harmonic of the fundamental cavity frequency are observed by adjusting the intra-cavity polarization state.

  13. A multi-wavelength erbium-doped fiber ring laser using an intrinsic Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Jauregui-Vazquez, D.; Rojas-Laguna, R.; Estudillo-Ayala, J. M.; Hernandez-Garcia, J. C.; Lopez-Dieguez, Y.; Sierra-Hernandez, J. M.

    2016-10-01

    In this experimental paper, a multi-wavelength erbium-doped ring fiber laser based on an all fiber intrinsic Fabry-Perot interferometer is presented and demonstrated. The interferometer was fabricated by an arc and splicing technique using hollow core photonic crystal fiber (HCPCF) and conventional single mode fiber (SMF28). The fiber laser can be operated in single, dual and triple lasing mode by applying a transversal load over the all fiber interferometer. The laser spectrums present minimal mode spacing of 1 nm, high wavelength stability and power fluctuations around 0.5 dB. The average signal to noise ratio (SNR) of the laser emissions spectrum is around 35 dB. This fiber laser offers low cost, compactness and high wavelength stability.

  14. Highly ytterbium-doped bismuth-oxide-based fiber.

    PubMed

    Ohara, Seiki; Kuroiwa, Yutaka

    2009-08-01

    Thermally stable highly ytterbium-doped bismuth-oxide-based glasses have been investigated. The absorbance increased linearly with Yb(2)O(3) concentration, reaching 7800 dB/m with 3 mol-% of Yb(2)O(3). An ytterbium-doped bismuth-oxide-based fiber has also been fabricated with a fiber loss of 0.24 dB/m. A fiber laser is also demonstrated, and it shows a slope efficiency of 36%.

  15. Characteristics research on self-amplified distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Song, Zhiqiang; Qi, Haifeng; Guo, Jian; Wang, Chang; Peng, Gangding

    2014-09-01

    A distributed feedback (DFB) fiber laser with a ratio of the backward to forward output power of 1:100 was composed by a 45-mm-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL-980-Hp erbium-doped fiber to absorb the surplus pump power after the active phase-shifted fiber grating and get population inversion. By using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with the narrow line-width and low noise, a narrow-band light filter consisting of a fiber Bragg grating (FBG) with the same Bragg wavelength as the laser and an optical circulator was used to filter the amplified spontaneous emission (ASE) noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, and a DFB fiber laser with the 32.5-mW output power, 11.5-kHz line width, and -87-dB/Hz relative intensity noise (RIN) at 300 mW of 980 nm pump power was brought out.

  16. Miniature fiber-optic multiphoton microscopy system using frequency-doubled femtosecond Er-doped fiber laser.

    PubMed

    Huang, Lin; Mills, Arthur K; Zhao, Yuan; Jones, David J; Tang, Shuo

    2016-05-01

    We report on a miniature fiber-optic multiphoton microscopy (MPM) system based on a frequency-doubled femtosecond Er-doped fiber laser. The femtosecond pulses from the laser source are delivered to the miniature fiber-optic probe at 1.58 µm wavelength, where a standard single mode fiber is used for delivery without the need of free-space dispersion compensation components. The beam is frequency-doubled inside the probe by a periodically poled MgO:LiNbO3 crystal. Frequency-doubled pulses at 786 nm with a maximum power of 80 mW and a pulsewidth of 150 fs are obtained and applied to excite intrinsic signals from tissues. A MEMS scanner, a miniature objective, and a multimode collection fiber are further used to make the probe compact. The miniature fiber-optic MPM system is highly portable and robust. Ex vivo multiphoton imaging of mammalian skins demonstrates the capability of the system in imaging biological tissues. The results show that the miniature fiber-optic MPM system using frequency-doubled femtosecond fiber laser can potentially bring the MPM imaging for clinical applications.

  17. Miniature fiber-optic multiphoton microscopy system using frequency-doubled femtosecond Er-doped fiber laser.

    PubMed

    Huang, Lin; Mills, Arthur K; Zhao, Yuan; Jones, David J; Tang, Shuo

    2016-05-01

    We report on a miniature fiber-optic multiphoton microscopy (MPM) system based on a frequency-doubled femtosecond Er-doped fiber laser. The femtosecond pulses from the laser source are delivered to the miniature fiber-optic probe at 1.58 µm wavelength, where a standard single mode fiber is used for delivery without the need of free-space dispersion compensation components. The beam is frequency-doubled inside the probe by a periodically poled MgO:LiNbO3 crystal. Frequency-doubled pulses at 786 nm with a maximum power of 80 mW and a pulsewidth of 150 fs are obtained and applied to excite intrinsic signals from tissues. A MEMS scanner, a miniature objective, and a multimode collection fiber are further used to make the probe compact. The miniature fiber-optic MPM system is highly portable and robust. Ex vivo multiphoton imaging of mammalian skins demonstrates the capability of the system in imaging biological tissues. The results show that the miniature fiber-optic MPM system using frequency-doubled femtosecond fiber laser can potentially bring the MPM imaging for clinical applications. PMID:27231633

  18. Miniature fiber-optic multiphoton microscopy system using frequency-doubled femtosecond Er-doped fiber laser

    PubMed Central

    Huang, Lin; Mills, Arthur K.; Zhao, Yuan; Jones, David J.; Tang, Shuo

    2016-01-01

    We report on a miniature fiber-optic multiphoton microscopy (MPM) system based on a frequency-doubled femtosecond Er-doped fiber laser. The femtosecond pulses from the laser source are delivered to the miniature fiber-optic probe at 1.58 µm wavelength, where a standard single mode fiber is used for delivery without the need of free-space dispersion compensation components. The beam is frequency-doubled inside the probe by a periodically poled MgO:LiNbO3 crystal. Frequency-doubled pulses at 786 nm with a maximum power of 80 mW and a pulsewidth of 150 fs are obtained and applied to excite intrinsic signals from tissues. A MEMS scanner, a miniature objective, and a multimode collection fiber are further used to make the probe compact. The miniature fiber-optic MPM system is highly portable and robust. Ex vivo multiphoton imaging of mammalian skins demonstrates the capability of the system in imaging biological tissues. The results show that the miniature fiber-optic MPM system using frequency-doubled femtosecond fiber laser can potentially bring the MPM imaging for clinical applications. PMID:27231633

  19. Hollow steel tips for reducing distal fiber burn-back during thulium fiber laser lithotripsy.

    PubMed

    Hutchens, Thomas C; Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

    2013-07-01

    The use of thulium fiber laser (TFL) as a potential alternative laser lithotripter to the clinical holmium:YAG laser is being studied. The TFL's Gaussian spatial beam profile provides efficient coupling of higher laser power into smaller core fibers without proximal fiber tip degradation. Smaller fiber diameters are more desirable, because they free up space in the single working channel of the ureteroscope for increased saline irrigation rates and allow maximum ureteroscope deflection. However, distal fiber tip degradation and "burn-back" increase as fiber diameter decreases due to both excessive temperatures and mechanical stress experienced during stone ablation. To eliminate fiber tip burn-back, the distal tip of a 150-μm core silica fiber was glued inside 1-cm-long steel tubing with fiber tip recessed 100, 250, 500, 1000, or 2000 μm inside the steel tubing to create the hollow-tip fiber. TFL pulse energy of 34 mJ with 500-μs pulse duration and 150-Hz pulse rate was delivered through the hollow-tip fibers in contact with human calcium oxalate monohydrate urinary stones during ex vivo studies. Significant fiber tip burn-back and degradation was observed for bare 150-μm core-diameter fibers. However, hollow steel tip fibers experienced minimal fiber burn-back without compromising stone ablation rates. A simple, robust, compact, and inexpensive hollow fiber tip design was characterized for minimizing distal fiber burn-back during the TFL lithotripsy. Although an increase in stone retropulsion was observed, potential integration of the hollow fiber tip into a stone basket may provide rapid stone vaporization, while minimizing retropulsion.

  20. Adaptive fiber optics collimator based on flexible hinges.

    PubMed

    Zhi, Dong; Ma, Yanxing; Ma, Pengfei; Si, Lei; Wang, Xiaolin; Zhou, Pu

    2014-08-20

    In this manuscript, we present a new design for an adaptive fiber optics collimator (AFOC) based on flexible hinges by using piezoelectric stacks actuators for X-Y displacement. Different from traditional AFOC, the new structure is based on flexible hinges to drive the fiber end cap instead of naked fiber. We fabricated a real AFOC based on flexible hinges, and the end cap's deviation and resonance frequency of the device were measured. Experimental results show that this new AFOC can provide fast control of tip-tilt deviation of the laser beam emitting from the end cap. As a result, the fiber end cap can support much higher power than naked fiber, which makes the new structure ideal for tip-tilt controlling in a high-power fiber laser system.

  1. Endovenous laser ablation with TM-fiber laser

    NASA Astrophysics Data System (ADS)

    Somunyudan, Meral Filiz; Topaloglu, Nermin; Ergenoglu, Mehmet Umit; Gulsoy, Murat

    2011-03-01

    Endovenous Laser Ablation (EVLA) has become a popular minimally invasive alternative to stripping in the treatment of saphenous vein reflux. Several wavelengths have been proposed; of which 810, 940 and 980- nm are the most commonly used. However, the most appropriate wavelength is still the subject of debate. Thermal shrinkage of collagenous tissue during EVLA plays a significant role in the early and late results of the treatment. The aim of this study is to compare the efficacy of 980 and 1940-nm laser wavelengths in the treatment of varicose veins. In this study, 980 and 1940-nm lasers at different power settings (8/10W for 980-nm, 2/3W for 1940-nm) were used to irradiate stripped human veins. The most prominent contraction and narrowing in outer and inner diameter were observed with the 1940-nm at 2W, following 980-nm at 8W, 1940-nm at 3W and finally 980-nm at 10W. The minimum carbonization was observed with the 1940-nm at 2W. As a conclusion, 1940-nm Tm-fiber laser which has a significant effect in the management of varicose veins due to more selective energy absorption in water and consequently in the vein is a promising method in the management of varicose veins.

  2. OSNR enhancement utilizing large effective area fiber in a multiwavelength Brillouin-Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Sonee Shargh, R.; Al-Mansoori, M. H.; Anas, S. B. A.; Sahbudin, R. K. Z.; Mahdi, M. A.

    2011-02-01

    We propose a simple Brillouin-Raman multi-channel fiber laser with supportive Rayleigh scattering in a linear cavity without employing any feedback mirrors at the end of cavity. Brillouin and the consequences of Rayleigh scattering work as virtual mirrors. We employ a section of large effective area fiber in addition to a section of dispersion compensating fiber to enhance the optical signal-to-noise ratio of multi-channel Brillouin-Raman comb fiber laser. We able to produce a flat comb fiber laser with 37 nm bandwidth from 1539 to 1576 nm built-in 460 Stokes lines with 0.08 nm spacing. Furthermore, this Brillouin-Raman comb fiber laser has acceptable optical signal-to-noise ratio value of 16.8 dB for the entire bandwidth with excellent flatness and low discrepancies in power levels of about 2.3 dB between odd and even channels.

  3. Influence of the UV-induced fiber loss on the distributed feedback fiber lasers

    NASA Astrophysics Data System (ADS)

    Fan, Wei; Chen, Bai; Qiao, Qiquan; Chen, Jialing; Lin, Zunqi

    2003-06-01

    It was found that the output power of the distributed feedback fiber lasers would be improved after annealing or left unused for several days after the laser had been fabricated, and the output of the fundamental mode would not increase but be clamped while the ±1 order modes would be predominant with the enhancement of the coupling coefficient during the fabrication. The paper discussed the influence of UV-induced fiber loss on the fiber phase-shifted DFB lasers. Due to the gain saturation and fiber internal loss, which included the temperament loss and permanent loss, there was an optimum coupling coefficient for the DFB fiber lasers that the higher internal fiber loss corresponded to the lower optimum values of coupling coefficient.

  4. 30  W fluoride glass all-fiber laser at 2.94  μm.

    PubMed

    Fortin, Vincent; Bernier, Martin; Bah, Souleymane T; Vallée, Réal

    2015-06-15

    We report the demonstration of a 2938 nm erbium-doped fluoride glass fiber laser delivering a record output power of 30.5 W in continuous wave operation. The passively cooled all-fiber laser cavity based on intracore fiber Bragg gratings has an overall laser efficiency of 16% as a function of the launched pump power at 980 nm and a single-mode output beam quality of M2<1.2. This power scaling demonstration of a fiber laser operating near the vibrational resonance of water is likely to have a significant impact on several biomedical applications. PMID:26076286

  5. Statistical characteristics of surface integrity by fiber laser cutting of Nitinol vascular stents

    NASA Astrophysics Data System (ADS)

    Fu, C. H.; Liu, J. F.; Guo, Andrew

    2015-10-01

    Nitinol alloys have been widely used in manufacturing of vascular stents due to the outstanding properties such as superelasticity, shape memory, and superior biocompatibility. Laser cutting is the dominant process for manufacturing Nitinol stents. Conventional laser cutting usually produces unsatisfactory surface integrity which has a significant detrimental impact on stent performance. Emerging as a competitive process, fiber laser with high beam quality is expected to produce much less thermal damage such as striation, dross, heat affected zone (HAZ), and recast layer. To understand the process capability of fiber laser cutting of Nitinol alloy, a design-of-experiment based laser cutting experiment was performed. The kerf geometry, roughness, topography, microstructure, and hardness were studied to better understand the nature of the HAZ and recast layer in fiber laser cutting. Moreover, effect size analysis was conducted to investigate the relationship between surface integrity and process parameters.

  6. Chromatic polarization effects of swept waveforms in FDML lasers and fiber spools.

    PubMed

    Wieser, Wolfgang; Palte, Gesa; Eigenwillig, Christoph M; Biedermann, Benjamin R; Pfeiffer, Tom; Huber, Robert

    2012-04-23

    We present detailed investigations of chromatic polarization effects, caused by fiber spools used in FDML lasers and buffering spools for rapidly wavelength swept lasers. We introduce a novel wavelength swept FDML laser source, specially tailored for polarization sensitive optical coherence tomography (OCT) which switches between two different linear polarization states separated by 45°, i.e. 90° on the Poincaré sphere. The polarization maintaining laser cavity itself generates a stable linear polarization state and uses an external buffering technique in order to provide alternating polarization states for successive wavelength sweeps. The design of the setup is based on a comprehensive analysis of the polarization output from FDML lasers, using a novel 150 MHz polarization analyzer. We investigate the fiber polarization properties related to swept source OCT for different fiber delay topologies and analyze the polarization state of different FDML laser sources.

  7. High-power thulium fiber laser Q switched with single-layer graphene.

    PubMed

    Tang, Yulong; Yu, Xuechao; Li, Xiaohui; Yan, Zhiyu; Wang, Qi Jie

    2014-02-01

    We report high-power 2 μm Tm3+ fiber lasers passively Q switched by double-piece single-layer graphene transferred onto a glass plate. Through manipulating intracavity laser beam size and increasing pump ratios, an average power of 5.2 W is directly achieved from the laser oscillator with an optical-to-optical slope efficiency of 26%. The laser pulse energy can be as high as ∼18  μJ, comparable to that from actively Q-switched fiber lasers. The narrowest pulse width is 320 ns, and the pulse repetition rate can be tuned from tens of kilohertz to 280 kHz by changing the pump power. To the best of our knowledge, this is the highest average power and pulse energy, as well as the narrowest pulse width, from graphene-based Q-switched 2 μm fiber lasers.

  8. Microscopic analysis of laser-induced proximal fiber tip damage during holmium:YAG and thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2016-04-01

    The thulium fiber laser (TFL) is being studied as an alternative to the standard holmium:YAG laser for lithotripsy. The TFL beam originates within an 18-μm-core thulium-doped silica fiber, and its near single mode, Gaussian beam profile enables transmission of higher laser power through smaller (e.g., 50- to 150-μm core) fibers than possible during holmium laser lithotripsy. This study examines whether the more uniform TFL beam profile also reduces proximal fiber tip damage compared with the holmium laser multimodal beam. Light and confocal microscopy images were taken of the proximal surface of each fiber to inspect for possible laser-induced damage. A TFL beam at a wavelength of 1908 nm was coupled into 105-μm-core silica fibers, with 35-mJ energy, and 500-μs pulse duration, and 100,000 pulses were delivered at each pulse rate setting of 50, 100, 200, 300, and 400 Hz. For comparison, single use, 270-μm-core fibers were collected after clinical holmium laser lithotripsy procedures performed with standard settings (600 mJ, 350 μs, 6 Hz). Total laser energy, number of laser pulses, and laser irradiation time were recorded, and fibers were rated for damage. For TFL studies, output pulse energy and average power were stable, and no proximal fiber damage was observed at settings up to 35 mJ, 400 Hz, and 14 W average power (n=5). In contrast, confocal microscopy images of fiber tips after holmium lithotripsy showed proximal fiber tip degradation, indicated by small ablation craters on the scale of several micrometers in all fibers (n=20). In summary, the proximal fiber tip of a 105-μm-core fiber transmitted up to 14 W of TFL power without degradation, compared to degradation of 270-μm-core fibers after transmission of 3.6 W of holmium laser power. The smaller and more uniform TFL beam profile may improve fiber lifetime, and potentially translate into lower costs for the surgical disposables as well.

  9. Design and refinement of rare earth doped multicore fiber lasers

    NASA Astrophysics Data System (ADS)

    Prudenzano, F.; Mescia, L.; Di Tommaso, A.; Surico, M.; De Sario, M.

    2013-09-01

    A novel multicore ytterbium doped fiber laser is designed, with the target of maximizing both the effective mode area and the beam quality, by means of a complete home-made computer code. It can be employed to construct high power and Quasi-Gaussian beam lasers. The novel laser configuration exploits a single mode multicore fiber and does not need Talbot cavity or other in-phase mode selection mechanisms. This is an innovative solution, because to the best of our knowledge, for the first time, we have designed a truly single-mode multicore fiber laser. For comparison we have optimized two other laser configurations which are well known in literature, both employing a multimode multicore fiber and a Talbot cavity as a feedback for the in-phase supermode selection. All three multicore fibers, constituted by the same glass, are doped with the same ytterbium ion concentration and pumped with the same input power. Multimodal fiber lasers exhibit lower beam quality, i.e. a higher beam quality factor M2, with respect to the single mode one, even if suitable Talbot cavities are designed, but they are very competitive when a more compact laser cavity is required for the same output power. The novel single mode nineteen core laser exhibits a simulated effective mode area Aeff = 703 μm2 and a beam quality factor M2 = 1.05, showing better characteristics than the other two lasers.

  10. High Strength, Large Core Pure Silica Fibers For Laser Surgery

    NASA Astrophysics Data System (ADS)

    Skutnik, B. J.; Hodge, M. H.; Clarkin, J. P.

    1988-06-01

    Recently many researchers, doctors and instrument companies have begun developing fiber optic laser power delivery systems to accomplish less traumatic surgery or localized irradiation treatment(1). With high power levels, particularly in short bursts, large core fibers are needed to keep the power densities from approaching the damage threshold of silica. Among the many advantages of using optical fibers in laser surgery are the following: microsurgery can be employed, trauma is reduced, access to interior through catheter introduction into vascular, gastrointestinal or respiratory tracts, accurate application of laser power through a flexible lightweight medium to provide localized irradiation as well as surgical removal, and the devices are sterilizable and of moderate cost permitting one-time use (disposable) probes. To achieve these wonderful gains in surgical procedures, the optical fibers must satisfy many optical and mechanical requirements. In use the optical fibers are often required to bend around curves or obstructions to reach the desired application area. Large tensile stresses can occur on the outer radius of the bent fiber, especially with large core fibers, thus high strength fibers are needed. Furthermore, since body fluids are primarily water, stress corrosion and fatigue(2-6) will occur. Therefore, the fibers should have excellent fatigue resistance as well as high strength. This paper further describes these requirements and presents details about an optical fiber which meets these requirements and provides additional very useful properties. These fibers with pure silica cores are called Hard Clad Silica, HCS*, fibers because of their hard bonded cladding over silica structure.

  11. Intramural Comparison of NIST Laser and Optical Fiber Power Calibrations

    PubMed Central

    Lehman, John H.; Vayshenker, Igor; Livigni, David J.; Hadler, Joshua

    2004-01-01

    The responsivity of two optical detectors was determined by the method of direct substitution in four different NIST measurement facilities. The measurements were intended to demonstrate the determination of absolute responsivity as provided by NIST calibration services at laser and optical-communication wavelengths; nominally 633 nm, 850 nm, 1060 nm, 1310 nm, and 1550 nm. The optical detectors have been designated as checks standards for the purpose of routine intramural comparison of our calibration services and to meet requirements of the NIST quality system, based on ISO 17025. The check standards are two optical-trap detectors, one based on silicon and the other on indium gallium arsenide photodiodes. The four measurement services are based on: (1) the laser optimized cryogenic radiometer (LOCR) and free field collimated laser light; (2) the C-series isoperibol calorimeter and free-field collimated laser light; (3) the electrically calibrated pyroelectric radiometer and fiber-coupled laser light; (4) the pyroelectric wedge trap detector, which measures light from a lamp source and monochromator. The results indicate that the responsivity of the check standards, as determined independently using the four services, agree to within the published expanded uncertainty ranging from approximately 0.02 % to 1.24 %. PMID:27366611

  12. Period-control and chaos-anti-control of a semiconductor laser using the twisted fiber

    NASA Astrophysics Data System (ADS)

    Yan, Sen-Lin

    2016-09-01

    A novel semiconductor laser system is presented based on a twisted fiber. To study the period-control and chaos-anti-control of the laser system, we design a type of optic path as a control setup using the combination of the twisted fiber and the polarization controller while we present a physical dynamics model of the delayed dual-feedback laser containing the twisted fiber effect. We give an analysis of the effect of the twisted fiber on the laser. We use the effects of the delayed phase and the rotation angle of the twisted fiber and the characteristics of the system to achieve control of the laser. The laser is deduced to a stable state, a double-periodic state, a period-6 state, a period-8 state, a period-9 state, a multi-period state, beat phenomenon, and so on. The periodic laser can be anti-controlled to chaos. Some chaos-anti-control area is found. The laser system is very useful for the study of chaos-control of the laser setup and the applications of some physics effects.

  13. Characteristics research of self-amplified distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Song, Zhiqiang; Qi, Haifeng; Guo, Jian; Wang, Chang; Peng, Gangding

    2013-09-01

    A distributed feedback (DFB) fiber laser with a ratio of backward to forward output power of 1:100 was composed by a 45mm length asymmetrical phase-shifted fiber grating fabricated on 50mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL980-Hp erbium-doped fiber to absorb surplus pump power after the active phase-shifted fiber grating and get population inversion. Using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with narrow line-width and low noise, a narrow-band light filter consisted of a FBG with the same Bragg wavelength as the laser and an optical circulator was used to filter the ASE noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, a DFB fiber laser of 32.5mW output power, 11.5 kHz line width, and -87dB/Hz relative intensity noise (RIN) at 300mW of 980 nm pump power was brought out.

  14. Hole drilling with fiber-optically delivered visible lasers

    SciTech Connect

    Kautz, D.D.; Berzins, L.V.; Dragon, E.P.

    1994-12-31

    The use of lasers for high-speed drilling of holes in materials is well documented. To allow easier use of lasers in manufacturing processes, fiber-optically delivered beams are preferable to the use of conventional optics. Lawrence Livermore National Laboratory (LLNL) has adapted fiber-optic technology to its visible light, copper vapor lasers for use in hole drilling studies. Visible lasers afford better coupling of light to the workpiece and when fiber-optically delivered, allow high quality holes to be drilled in difficult accessibility areas and with easier setup. A fiber-optic delivery system was attached to the presently hard-optic copper vapor laser system. This system consisted of a 0.6 mm (0.024 in.) fiber that was then telescoped and refocused by a hard optics package at the workstation end of the fiber. The optics package produced a 0.2 mm (0.008 in.) focused spot size at the workpiece. This system was then run down to a 3-axis CNC machining table to allow part movement for these studies. The fiber-optically delivered light was found to work extremely well for drilling small diameter holes. In summary, it was found that fiber-optically delivered, visible laser beams have several advantages in drilling over those same beams delivered through conventional hard optics. These include much easier setup, reduced system maintenance, and typically higher hole quality.

  15. Fiber Optic Laser Delivery For Endarterectomy Of Experimental Atheromas

    NASA Astrophysics Data System (ADS)

    Eugene, John; Pollock, Marc E.; McColgan, Stephen J.; Hammer-Wilson, Marie; Berns, Michael W.

    1986-08-01

    Fiber optic delivery of argon ion laser energy and Nd-YAG laser energy were compared by the performance of open laser endarterectomy in the rabbit arteriosclerosis model. In Group I, 6 open laser endarterectomies were performed with an argon ion laser (488 nm and 514.5 nm) with the laser beam directed through a 400 pm quartz fiber optic. In Group II, 6 open laser endarterectomies were performed with a Nd-YAG laser (1.06 pm) with the laser beam directed through a 600 pm quartz fiber optic. Gross and light microscopic examination revealed smooth endarterectomy surfaces with tapered end points in Group I. In Group II, the endarterectomy surfaces were uneven and perforation occurred at 5/6 end points. Although energy could be precisely delivered with each laser by fiber optics, satisfactory results could only be achieved with the argon ion laser because argon ion energy was well absorbed by atheromas. Successful intravascular laser use requires a strong interaction between wavelength and atheroma as well as a precise delivery system.

  16. Fiber optic coherent laser radar 3D vision system

    SciTech Connect

    Clark, R.B.; Gallman, P.G.; Slotwinski, A.R.; Wagner, K.; Weaver, S.; Xu, Jieping

    1996-12-31

    This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution.

  17. 80-W green KTP laser used in photoselective laser vaporization of the prostrate by frequency doubling of Yb 3+ -doped large-mode area fiber laser

    NASA Astrophysics Data System (ADS)

    Xia, Hongxing; Li, Zhengjia

    2007-05-01

    Photoselective laser vaporization of the prostate (PVP) is the most promising method for the treatment of benign prostatic hyperplasia (BPH), but KTP lasers used in PVP with lamp-pumped are low efficient .To increase the efficiency , we develop a 80-W, 400kHz, linearly polarized green laser based on a frequency-doubled fiber laser. A polarization-maintaining large-mode area (LMA) fiber amplifier generate polarized 1064nm fundamental wave by amplifying the seed signal from a composite Cr 4+:YAG-Nd 3+:YAG crystal fiber laser. The fundamental wave is injected into a KTP crystal with confined temperature management to achieve second harmonic generation (SHG). The overall electrical efficiency to the green portion of the spectrum is 10%.80-W maintenance-free long-lifetime KTP laser obtained can well satisfy the need of PVP.

  18. kW-level narrow linewidth fiber amplifier seeded by a fiber Bragg grating based oscillator.

    PubMed

    Hao, Jinping; Zhao, Hong; Zhang, Dayong; Zhang, Liming; Zhang, Kun

    2015-05-20

    This paper demonstrates an all-fiber narrow linewidth amplifier with a seed based on narrow linewidth fiber Bragg gratings (FBGs). The fiber amplifier achieves a narrow bandwidth output of 823 W, with an opto-optic efficiency of 84.5%. The pair of FBGs in the seed configuration helps to assure a narrow linewidth of the laser as 0.08 nm. In the laser profile, we introduce a cladding stripper with a sectional structure, which realizes high pump power leakage with high efficiency. The paper also discusses the impact of seed linewidth and fiber length on the SBS threshold in a narrow bandwidth laser. Based on this analysis, we discovered ways to inhibit SBS onset and scale power output. PMID:26192524

  19. High Power 938nm Cladding Pumped Fiber Laser

    SciTech Connect

    Dawson, J; Beach, R; Brobshoff, A; Liao, Z; Payne, S; Pennington, D; Taylor, L; Hackenberg, W; Bonaccini, D

    2002-12-26

    We have developed a Nd:doped cladding pumped fiber amplifier, which operates at 938nm with greater than 2W of output power. The core co-dopants were specifically chosen to enhance emission at 938nm. The fiber was liquid nitrogen cooled in order to achieve four-level laser operation on a laser transition that is normally three level at room temperature, thus permitting efficient cladding pumping of the amplifier. Wavelength selective attenuation was induced by bending the fiber around a mandrel, which permitted near complete suppression of amplified spontaneous emission at 1088nm. We are presently seeking to scale the output of this laser to 10W. We will discuss the fiber and laser design issues involved in scaling the laser to the 10W power level and present our most recent results.

  20. Theoretical and experimental research on the ˜980-nm Yb-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Wang, Yanshan; Ke, Weiwei; Ma, Yi; Sun, Yinhong; Feng, Yujun

    2016-07-01

    The output properties of the ˜980-nm Yb-doped fiber laser versus pump power and core-cladding ratio of gain fiber, also the amplified spontaneous emission (ASE) at different wavelengths of seed laser, are investigated theoretically. An all-fiber amplifier based on different wavelengths of seed laser at 974.4, 977, and 981.7 nm brings the studies on parasitic oscillation and ASE in the ˜980-nm Yb-doped fiber amplifier. Through the theoretical and experimental research, we found that the controlling of three-level ASE around ˜980-nm is pivotal for obtaining a high-power 980-nm Yb-doped fiber amplifier.