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Sample records for brillouin fiber laser

  1. L-band double Brillouin frequency spaced tunable multiwavelength Brillouin fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Wang, Tianshu; Jia, Qingsong; Dong, Keyan

    2014-12-01

    A tunable multi-wavelength Brillouin fiber laser with double Brillouin frequency spacing based on a four-port circulator is experimentally demonstrated. The fiber laser configuration formed by four-port circulator isolates the odd-order Brillouin stokes signal to circulate within the cavity only. In addition, it also allows propagation of the incoming Brillouin pump and even-order Stokes signals from four-port circulator to output coupler .A L-band erbiumdoped fiber (EDF) with 1480nm pump is used to amplify Stokes signals and to get more output channels. At the Brillouin pump power of 8dBm and the 1480 nm pump power of 200mw, 5 output channels with double Brillouin frequency spacing and tuning range of 20 nm from 1568nm to 1588nm are achieved.

  2. Double Brillouin frequency spaced multiwavelength Brillouin-erbium fiber laser with 50 nm tuning range

    NASA Astrophysics Data System (ADS)

    Zhao, J. F.; Liao, T. Q.; Zhang, C.; Zhang, R. X.; Miao, C. Y.; Tong, Z. R.

    2012-09-01

    A 50 nm tuning range multiwavelength Brillouin-erbium fiber laser (MWBEFL) with double Brillouin frequency spacing is presented. Two separated gain blocks with symmetrical architecture, consisted by erbium-doped fiber amplifiers (EDFAs) and Brillouin gain media, are used to generate double Brillouin frequency spacing. The wider tuning range is realized by eliminating the self-lasing cavity modes existing in conventional MWBEFLs because of the absence of the physical mirrors at the ends of the linear cavity. The Brillouin pump (BP) is preamplified by the EDFA before entering the single-mode fiber (SMF), which leads to the reduction of threshold power and the generation enhancement of Brillouin Stokes (BS) signals. Four channels with 0.176 nm spacing are achieved at 2 mW BP power and 280 mW 980 nm pump power which can be tuned from 1525 to 1575 nm.

  3. Dynamics of ultra-long Brillouin fiber laser

    NASA Astrophysics Data System (ADS)

    Fotiadi, Andrei A.; Lobach, Ivan; Mégret, Patrice

    2013-02-01

    We report on experimental studies of random lasing realized in optical fibers with the use of Brillouin amplification and Rayleigh backscattering employed as a distributed feedback instead of a cavity mirror. In our experiment 25-km-long high quality standard telecom single-mode fiber was employed for Rayleigh reflection uniformly distributed over all fiber length. We have observed a clear competition between a classical Brillouin scattering and Brillouin lasing. Presence of extended fluctuation-free fragments in the recorded oscilloscope traces highlights Stokes power statistics typical for laser radiation rather than for Brillouin process. The results of the experiments are in a perfect agreement with the model of Brillouin - Rayleigh cooperative process in long fibers.

  4. Microwave photonic filter using multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency shift

    SciTech Connect

    Loh, K. K.; Yeo, K. S.; Shee, Y. G.

    2015-04-24

    A microwave photonic filter based on double-Brillouin-frequency spaced multiwavelength Brillouin-erbium fiber laser (BEFL) is experimentally demonstrated. The filter selectivity can be easily adjusted by tuning and apodizing the optical taps generated from the multiwavelength BEFL. Reconfiguration of different frequency responses are demonstrated.

  5. Compact two wavelength Brillouin fiber laser sensor with double Brillouin frequency spacing

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Zhang, Mingjiang; Zhang, Jianzhong; Han, Hong; Yi, Xiaogang; Zhang, Jianguo; Wang, Yuncai

    2016-12-01

    A compact two wavelength Brillouin fiber laser (BFL) sensor with double Brillouin frequency spacing is proposed and demonstrated. In the experiment, 20 m polarization maintaining fiber is used as the sensing element and Brillouin gain medium. This short cavity configuration not only guarantees single longitudinal mode operation of two Stokes wavelengths, but also can effectively reduce external perturbations, complexity and noise of BFL in the absence of an erbium-doped fiber amplifier in intra-cavity. In experiment, about 2 MHz/°C sensitivity of beat frequency between the pump and the 2nd-order Stokes wavelength keep in good agreement with the theoretical value. Meanwhile, 0.2 °C temperature stability and  ±0.1 dB power fluctuation are better than the traditional structure. The system is simple and stable, making it convenient for more applications.

  6. 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.

  7. Hybrid Brillouin/thulium multiwavelength fiber laser with switchable single- and double-Brillouin-frequency spacing.

    PubMed

    Hu, Kai; Kabakova, Irina V; Lefrancois, Simon; Hudson, Darren D; He, Sailing; Eggleton, Benjamin J

    2014-12-29

    We demonstrate a multiwavelength laser at 2 µm based on a hybrid gain scheme consisting of a Brillouin gain medium and a thulium-doped fiber. The laser has switchable frequency spacing, corresponding to the single and double Brillouin frequency shifts. In the 20 dB bandwidth, seven lasing channels with a frequency spacing of 0.1 nm (7.62 GHz) and eleven channels with a double-spacing of 0.2 nm (15.24 GHz) are obtained. A wavelength tunability of 1.3 nm is realized for both laser configurations by shifting the pump wavelength. Strong four wave mixing is observed in the double-spacing laser resulting in an improved performance: larger number of channels and better temporal stability.

  8. Thermal self-stability, multi-stability, and memory effects in Brillouin fiber lasers

    NASA Astrophysics Data System (ADS)

    Kotlicki, Omer; Scheuer, Jacob

    2017-02-01

    We demonstrate an inherently self-stable Brillouin fiber laser in telecom wavelengths, stemming from a natural thermal feedback mechanism. Such lasers demonstrate great stability which significantly overcomes the hampering drift often associated with fiber lasers.

  9. Observation of narrow linewidth spikes in the coherent Brillouin random fiber laser.

    PubMed

    Pang, Meng; Bao, Xiaoyi; Chen, Liang

    2013-06-01

    We observed narrow-linewidth lasing spikes in a coherent Brillouin random fiber laser, which uses a continuous-wave fiber laser as the pump source. In this random laser configuration, stimulated Brillouin scattering in a section of conventional single-mode fiber acts as the gain mechanism, while Rayleigh scattering in another section of the nonuniform fiber provides randomly distributed feedback. Above the lasing threshold, coherent random lasing spikes, with a linewidth of ~10 Hz, are measured at the top of the Brillouin gain spectrum. It results from high quality coherent resonance of the Brillouin Stokes light in this open laser cavity.

  10. Suppression of stimulated brillouin scattering in high power narrow linewidth fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, Liming; Yan, Chuping; Feng, Jinjun; Zhang, Kun; Zhu, Chen; Zhang, Dayong; Zhao, Hong; Zhou, Shouhuan

    2017-05-01

    In this paper, limitation factor of high power narrow linewidth fiber laser is analyzed. The influence of Stimulated Brillouin Scattering and its suppressing theory are discussed. Influences of frequency number and frequency spacing to Stimulated Brillouin Scattering are analyzed respectively by simulation. The results indicate that increasing frequency number and controlling frequency spacing can reduce the power spectrum density in fiber. Then the Stimulated Brillouin Scattering threshold is increased. Finally, the fiber laser output power is increased a lot.

  11. Brillouin-Erbium fiber laser with enhanced feedback coupling using common Erbium gain section.

    PubMed

    Samsuri, N M; Zamzuri, A K; Al-Mansoori, M H; Ahmad, A; Mahdi, M A

    2008-10-13

    We demonstrate an enhanced architecture of Brillouin-Erbium fiber laser utilizing the reverse-S-shaped fiber section as the coupling mechanism. The enhancement is made by locating a common section of Erbium-doped fiber next to the single-mode fiber to amplify the Brillouin pumps and the oscillating Stokes lines. The requirement of having two Erbium gain sections to enhance the multiple Brillouin Stokes lines generation is neglected by the proposed fiber laser structure. The mode competitions arise from the self-lasing cavity modes of the fiber laser are efficiently suppressed by the stronger pre-amplified Brillouin pump power before entering the single mode fiber section. The maximum output power of 20 mW is obtained from the proposed fiber laser with 10 laser lines that equally separated by 0.089 nm spacing.

  12. Brillouin-Raman comb fiber laser with cooperative Rayleigh scattering in a linear cavity.

    PubMed

    Zamzuri, A K; Md Ali, M I; Ahmad, A; Mohamad, R; Mahdi, M A

    2006-04-01

    We demonstrate a multiple-wavelength Brillouin comb laser with cooperative Rayleigh scattering that uses Raman amplification in dispersion-compensating fiber. The laser resonator is a linear cavity formed by reflector at each end of the dispersion-compensating fiber to improve the reflectivity of the Brillouin Stokes comb. Multiple Brillouin Stokes generation has been improved in terms of optical signal-to-noise ratio and power-level fluctuation between neighboring channels. Furthermore, the linewidth of the Brillouin Stokes is uniform within the laser output bandwidth.

  13. Analytical analysis of second-order Stokes wave in Brillouin ring fiber laser.

    PubMed

    Al-Asadi, H A; Abu Bakar, M H; Al-Mansoori, M H; Adikan, F R Mahamd; Mahdi, M A

    2011-12-05

    This paper details a theoretical modeling of Brillouin ring fiber laser which incorporates the interaction between multiple Brillouin Stokes signals. The ring cavity was pumped at several Brillouin pump (BP) powers and the output was measured through an optical coupler with various coupling ratios. The first-order Brillouin Stokes signal was saturated with the presence of the second-order Stokes signal in the cavity as a result of energy transfer between them. The outcome of the study found that the optimum point for the first-order Stokes wave performance is at laser power reduction of 10%. Resultantly, at the optimum output coupling ratio of 90%, the BFL was able to produce 19.2 mW output power at BP power and Brillouin threshold power of 60 and 21.3 mW respectively. The findings also exhibited the feasibility of the theoretical models application to ring-type Brillouin fiber laser of various design parameters.

  14. Multi-wavelength Brillouin fiber laser generation using dual-pass approach

    NASA Astrophysics Data System (ADS)

    Parvizi, R.; Ali, N. M.; Harun, S. W.; Emami, S. D.; Ahmad, H.

    2012-03-01

    A simple and compact multi-wavelength tunable Brillouin fiber laser (BFL) in conjunction with dual-pass approach is proposed and experimentally compared with the output of a conventional single ring cavity architecture. This BFL source is demonstrated using 10 km long non-zero dispersion shifted fiber (NZ-DSF) as a Brillouin gain medium. By single ring cavity configuration, odd-order Brillouin Stokes lines appear in the backward direction with the line spacing 0.16 nm (˜20 GHz) between each two consecutive waves. However, this single ring cavity in conjunction with dual-pass configuration is able to generate Brillouin Stokes lines with 0.08 nm spacing by providing bi-directional oscillations of Brillouin waves in both forward and backward directions. With a Brillouin pump power of 15.3 dBm, approximately up to 17 Brillouin Stokes lines are generated which is tunable over 40 nm tuning range.

  15. [94 km Brillouin distributed optical fiber sensors based on ultra-long fiber ring laser pumping].

    PubMed

    Yuan, Cheng-Xu; Wang, Zi-Nan; Jia, Xin-Hong; Li, Jin; Yan, Xiao-Dong; Cui, An-Bin

    2014-05-01

    A novel optical amplification configuration based on ultra-long fiber laser with a ring cavity was proposed and applied to Brillouin optical time-domain analysis (BOTDA) sensing system, in order to extend the measurement distance significantly. The parameters used in the experiment were optimized, considering the main limitations of the setup, such as depletion, self-phase modulation (SPM) and pump-signal relative intensity noise (RIN) transfer. Through analyzing Brillouin gain spectrum, we demonstrated distributed sensing over 94 km of standard single-mode fiber with 3 meter spatial resolution and strain/temperature accuracy of 28 /1. 4 degree C.

  16. Tunable multiwavelength SLM fiber laser based on Rayleigh and Brillouin scattering effects

    NASA Astrophysics Data System (ADS)

    Xiong, Huang; Zhang, Ruiwen; Chen, Guodong; Sun, Junqiang

    2017-05-01

    A widely tunable multiwavelength single-longitudinal-mode fiber laser based on Rayleigh and Brillouin scattering effects is proposed and experimentally demonstrated. The amplified Rayleigh backscattering of seed light serves as the original Brillouin pump while the Rayleigh and Brillouin scattering in the single mode fiber provide randomly distributed feedback. When the seed light wavelength varies in C-band with the power of -8 dBm, the fiber laser can generate more than nine lasing lines with narrow linewidth and their maximum power fluctuation is less than 2.4 dB. The lasing lines are stable, rigidly separated by 10.852 GHz.

  17. Stable and tunable self-seeded multiwavelength Brillouin-erbium fiber laser with higher OSNR

    NASA Astrophysics Data System (ADS)

    Zou, Hui; Yang, Ruilan; Shen, Xiao; Wei, Wei

    2016-07-01

    A stable and tunable self-seeded multiwavelength Brillouin-erbium fiber laser (BEFL) is designed and demonstrated based on a Single-Mode-Multimode-Single-Mode (SMS) fiber filter. The SMS filter is fabricated by splicing a 15 cm long multimode fiber between two single mode fibers. The self-excited Brillouin pump is internally achieved by cascaded stimulated Brillouin scattering (SBS) in the single mode fiber. By applying axial strain (from 0 to 466.7 μɛ) to the SMS filter with the same step of 66.7 μɛ , the multiwavelength of the output laser is tuned from 1553.58 to 1559.79 nm correspondingly, and the tunable range is 6.21 nm. The generation of up to 16 Brillouin Stokes wavelengths with 30 dB optical signal to noise ratio (OSNR) are obtained.

  18. Single Brillouin frequency shifted S-band multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier in ring cavity

    NASA Astrophysics Data System (ADS)

    Reshak, A. H.; Hambali, N. A. M. Ahmad; Shahimin, M. M.; Wahid, M. H. A.; Anwar, Nur Elina; Alahmed, Zeyad A.; Chyský, J.

    2016-10-01

    This paper is focusing on simulation and analyzing of S-band multi-wavelength Brillouin-Raman fiber laser performance utilizing fiber Bragg grating and Raman amplifier in ring cavity. Raman amplifier-average power model is employed for signal amplification. This laser system is operates in S-band wavelength region due to vast demanding on transmitting the information. Multi-wavelength fiber lasers based on hybrid Brillouin-Raman gain configuration supported by Raman scattering effect have attracted significant research interest due to its ability to produced multi-wavelength signals from a single light source. In multi-wavelength Brillouin-Raman fiber, single mode fiber is utilized as the nonlinear gain medium. From output results, 90% output coupling ratio has ability to provide the maximum average output power of 43 dBm at Brillouin pump power of 20 dBm and Raman pump power of 14 dBm. Furthermore, multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier is capable of generated 7 Brillouin Stokes signals at 1480 nm, 1510 nm and 1530 nm.

  19. Investigation on the effect of EDFA location in ring cavity Brillouin-Erbium fiber laser.

    PubMed

    Hambali, Nor Azura Malini A; Mahdi, Mohd Adzir; Al-Mansoori, Mohammed Hayder; Abas, Ahmad Fauzi; Saripan, M Iqbal

    2009-07-06

    We have investigated the characteristics of Brillouin-Erbium fiber laser (BEFL) with variation of Erbium-doped fiber amplifier (EDFA) locations in a ring cavity configuration. Three possible locations of the EDFA in the laser cavity have been studied. The experimental results show that the location of EDFA plays vital role in determining the output power and the tuning range. Besides the Erbium gain, Brillouin gain also contributes to the performance of the BEFL. By placing the EDFA next to the Brillouin gain medium (dispersion compensating fiber), the Brillouin pump signal is amplified thereby generating higher intensities of Brillouin Stokes line. This efficient process suppresses the free running self-lasing cavity modes from oscillating in cavity as a result of higher Stokes laser power and thus provide a wider tuning range. At the injected Brillouin pump power of 1.6 mW and the maximum 1480 nm pump power of 135 mW, the maximum Stokes laser power of 25.1 mW was measured and a tuning range of 50 nm without any self-lasing cavity modes was obtained.

  20. Enhanced multiwavelength generation in Brillouin fiber laser with pump noise suppression technique

    NASA Astrophysics Data System (ADS)

    Al-Alimi, A. W.; Cholan, N. A.; Yaacob, M. H.; Mahdi, M. A.

    2016-06-01

    A new multiwavelength Brillouin fiber laser (BFL) that provides a large number of Stokes lines with improved optical signal-to-noise ratio has been proposed and demonstrated. The BFL cavity is only formed by a nonlinear fiber loop mirror (NOLM) with 500 m long highly nonlinear fiber (HNLF). The BFL with improved performance is based on the suppression of the Brillouin pump noise floor utilizing a narrow tunable bandpass filter. The generation of Stokes lines covering up to a 33.67 nm wavelength range is achieved by setting the Brillouin pump signal within the HNLF’s zero dispersion wavelength and with power of 250 mW. This is owing to the combination of the stimulated Brillouin scattering and four-wave mixing effect in the NOLM structure.

  1. Tunable multiwavelength narrow linewidth Brillouin erbium fiber laser based on Rayleigh backscattering

    NASA Astrophysics Data System (ADS)

    Wang, Xiaorui; Yang, Yanfu; Liu, Meng; Yao, Yong

    2016-06-01

    A Rayleigh backscattering (RBS) assisted Brillouin erbium fiber laser scheme with multiwavelength narrow linewidth output is proposed and investigated experimentally. The stimulated Brillouin scattering and RBS take place at two conventional single-mode fibers (SMFs), respectively. RBS is used as a mechanism to compress the linewidth of each Stokes component, and it has been realized and maximized in conventional SMF by optimizing injection power of Stokes light through adjusting variable optical attenuator (VOA). By adjusting VOA attenuation, the laser can obtain three wavelengths output with 3 dB linewidth less than 2 KHz for each wavelength, or six wavelengths output with 3 dB linewidth less than 5 KHz.

  2. Broadband flat-amplitude multiwavelength Brillouin-Raman fiber laser with spectral reshaping by Rayleigh scattering.

    PubMed

    Wang, Zinan; Wu, Han; Fan, Mengqiu; Li, Yi; Gong, Yuan; Rao, Yunjiang

    2013-12-02

    In this letter, we propose a novel configuration for generating multiwavelength Brillouin-Raman fiber laser (MBRFL). The spectral reshaping effect introduced by Rayleigh scattering in a 50 km single mode fiber unifies the generated Brillouin comb in terms of both power level and linewidth. As a consequence, we are able to obtain a 40 nm flat-amplitude MBRFL with wide bandwidth from 1557 nm to 1597 nm covering >500 Stokes lines. This is, to the best of our knowledge, the widest flat-amplitude bandwidth of MBRFL with uniform Stokes combs using just a single Raman pump laser. The channel-spacing is 0.08 nm and the measured OSNR is higher than 12.5 dB. We also demonstrate that the output spectrum of the MBRFL is nearly unaffected over 14 dB range of Brillouin pumping power.

  3. High power, high signal-to-noise ratio single-frequency 1μm Brillouin all-fiber laser

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Hou, Yubin; Zhang, Qian; Jin, Dongchen; Sun, Ruoyu; Shi, Hongxing; Liu, Jiang; Wang, Pu

    2016-03-01

    We demonstrate a high-power, high signal-to-noise ratio single-frequency 1 μm Brillouin all-fiber laser with high slope efficiency. The Brillouin laser system consists of a high-power single-frequency fiber laser and a single-pass Brillouin ring cavity. The high-power single-frequency fiber laser is one-stage master-oscillator power amplifier with the maximum output power of 10.33 W, the signal-to-noise ratio of 50 dB and the slope efficiency of 46%. The Brillouin fiber laser is pumped by the amplified laser with a linewidth of 33 kHz and an output power of 2.61 W limited by the damage threshold of the optical isolator. By optimizing the length of the Brillouin ring cavity to 10 m, stable singlefrequency Brillouin fiber laser is obtained with 3 kHz linewidth owing to the linewidth narrowing effect. At the launched pump power of 2.15 W, the Brillouin fiber laser generates maximum output power of 1.4 W with a slope efficiency of 79% and the optical signal-to-noise ratio of 77 dB.

  4. Tunable multiwavelength L-band Brillouin-Erbium fiber laser utilizing passive EDF absorber section

    NASA Astrophysics Data System (ADS)

    Al-Mashhadani, T. F.; Al-Mansoori, M. H.; Jamaludin, M. Z.; Abdullah, F.; Abass, A. K.; Rawi, N. I. M.

    2013-12-01

    We demonstrate a simple tunable L-band multiwavelength Brillouin-Erbium fiber laser that utilizes a short passive erbium doped fiber (PEDF) as an absorber section. The impact of including the PEDF absorber section on the laser tunability is investigated. The proposed laser structure exhibits a wide tuning range of 24.4 nm (from 1583.5 nm to 1607.9 nm) at 1480 nm pump and Brillouin pump powers of 100 and 4 mW, respectively. This tuning range represents a 31% increase compared with a laser without a PEDF absorber section. The average number of stable output channels produced within this wavelength range is 16 channels with a spacing of 0.089 nm.

  5. Suppression of Stimulated Brillouin Scattering in Optical Fibers Using a Linearly Chirped Diode Laser

    DTIC Science & Technology

    2012-07-02

    modulation n,” Chin. Opt. Lett. 7, 29–31 (2009). 3 . D. Brown, M. Dennis, and W. Torruellas, “Improved phase modulation for SBS mitigation in kW -class fiber ...D. Björk, I. Majid, and K. Tankala, “ kW class, narrow-linewidth, counter pumped fiber amplifiers,” Solid State and Diode Laser Technical Review, 17...Suppression of stimulated Brillouin scattering in optical fibers using a linearly chirped diode laser J. O. White, 1,* A. Vasilyev, 2 J. P

  6. Development of laser light source with high stability for Brillouin optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Luo, Liang; Hu, Jiacheng; Liu, Zeguo; Wang, Chanyuan

    2016-10-01

    Temperature and strain measurement accuracy of Brillouin distributed optical fiber sensor are easily influenced by the performance of laser light source. A wavelength/power DFB semiconductor laser light source with high-stability used for Brillouin Fiber Sensing is designed. The laser light source works with constant-current drive circuit and temperature control circuit, which precisely controls drive current and operating temperature of the DFB semiconductor laser and makes the wavelength and optical power under control. The results show that: (1) the optical wavelength increases about 0.1nm and the power reduces about 0.05dBm when the temperature increased by 1°C . (2) The maximum drift of wavelength is 0.012nm and the maximum drift of optical power is 0.05dBm (0.0014mW) at 25 °C within one hour. The laser light source can completely meet the demand for Brillouin distributed optical fiber sensing.

  7. Random Brillouin fiber laser for tunable ultra-narrow linewidth microwave generation.

    PubMed

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

    2016-10-15

    Studies about random lasing phenomena taking place in disordered structures with amplification are gaining great interest, as they can support dual wavelength lasing without cavity length restriction and, hence, the tunable beat frequency in a microwave can be created in a random cavity and be amplified for applications in the information and communication technology. Here, we present a novel random Brillouin fiber laser scheme using the stimulated Brillouin scattering as gain and strong Rayleigh scattering feedback (10 km) in the single-mode fiber. The high degree of mutual coherence between the two Stokes beams from two different lasers leads to the generation of tunable ultra-narrow linewidth microwave signals (<10  Hz at 3 dB bandwidth) with a 70 dB contrast. This offers a simple and cost-effective design for microwave sources.

  8. Investigation of Brillouin Raman fiber laser operating at 1558 nm using THDF saturable absorber

    NASA Astrophysics Data System (ADS)

    Rizman, Z. I.; Zakaria, U. N.; Jusoh, Z.; Latiff, A. A.; Harun, S. W.

    2017-06-01

    We report a generation of Brillouin-Raman fiber laser (BRFL) which operating at 1558 nm wavelength. The proposed configuration utilizes a nonlinear gain medium of 7.7 km long dispersion compensating fiber (DCF) and using thulium holmium-doped fiber (THDF) as a fiber saturable absorber (SA). The self-started Q-switching operation starts at 569 mW pump power and keep stable until 721 mW pump level. The stable repetition rate of 22 kHz and pulse width of 1.791 µs are obtained with a signal to noise ratio (SNR) of 32 dB. This work shows the fiber SA can be used promisingly in a BRFL for pulse laser generation.

  9. Tunable microwave generation using dual-wavelength Brillouin O-band fiber laser

    NASA Astrophysics Data System (ADS)

    Aidit, S. N.; Ooi, S. I.; Hassan, N. A.; Ahmad, H.; Tiu, Z. C.

    2017-06-01

    A dual-wavelength fiber laser with a tunable output for generating microwave signals is proposed and demonstrated. The system utilizes stimulated Brillouin scattering inside a dispersion compensating fiber to generate the desired dual-wavelength output, which then beats to form the desired microwave frequency in the O-band region. A constant channel spacing of 0.072 nm is obtained for wavelengths ranging from 1260.0 nm to 1330.0 nm. The resulting microwave signal can also be tuned from 13.0 GHz to 12.3 GHz is achieved by controlling the Brillouin pump wavelength, and has a stable signal-to-noise ratio of 30.0 dB.

  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. Superluminal propagation in a highly nonlinear fiber embedded in a Brillouin laser ring cavity

    NASA Astrophysics Data System (ADS)

    Deng, Dinghuan; Gao, Weiqing; Liao, Meisong; Duan, Zhongchao; Cheng, Tonglei; Suzuki, Takenobu; Ohishi, Yasutake

    2014-03-01

    Superluminal propagation at negative group velocity was demonstrated in a highly nonlinear fiber embedded in a Brillouin laser ring cavity. A maximum advancement of 369 ns and strong Stokes lasing power of 482 mW were achieved when the cavity was pumped with a 1 MHz sinusoidal wave modulated signal at power level of 1 W. The frequency dependence of fast light in this fiber ring cavity was examined with modulation frequencies of 1 kHz to 15 MHz. a maximum fractional advancement of 0.54 was achieved at 10 kHz and a maximum negative group index of - 9480 was demonstrated at 1 kHz.

  12. Double spacing multi-wavelength L-band Brillouin erbium fiber laser with Raman pump

    NASA Astrophysics Data System (ADS)

    Ahmad, B. A.; Al-Alimi, A. W.; Abas, A. F.; Mokhtar, M.; Harun, S. W.; Mahdi, M. A.

    2012-11-01

    A new multi-wavelength Brillouin erbium fiber laser (BEFL), which operates in the L-band region with double frequency Brillouin spacing, is demonstrated. This design uses a Raman pump (RP) and a piece of 2 km highly nonlinear fiber as a gain medium. The double frequency spacing is achieved by employing a dual ring configuration, which is formed by utilizing a four-port circulator that removes the odd-order Stoke signals. Twenty Stokes and seventeen anti-Stokes lines, which have optical signal to noise ratio (OSNR) greater than 15 dB, are generated simultaneously with a spacing of 0.16 nm when Brillouin pump and RP powers were fixed at the optimum values of 8 dBm and 40 mW, respectively. The BEFL can be tuned in the range between 1591 nm to 1618 nm. The proposed configuration increases the number of lines generated and the OSNR, and thus allows a compact multi-wavelength laser source to be realized.

  13. An L-band multi-wavelength Brillouin-erbium fiber laser with switchable frequency spacing

    NASA Astrophysics Data System (ADS)

    Zhou, Xuefang; Hu, Kongwen; Wei, Yizhen; Bi, Meihua; Yang, Guowei

    2017-01-01

    In this paper, a novel L-band multi-wavelength Brillouin-erbium fiber laser consisting of two ring cavities is proposed and demonstrated. The frequency spacing can be switched, corresponding to the single and double Brillouin frequency shifts, by toggling the optical switch. Under a 980 nm pump power of 600 mw, and a Brillouin pump power of 4 mW and wavelength of 1599.4 nm, up to 16 Stokes signals with a frequency spacing of 0.089 nm and 5 Stokes signals with double spacing of 0.178 nm are generated. A wavelength tunability of 15 nm (1593 nm  -  1608 nm) is realized for both frequency spacings. The fluctuation of Stokes signals for both single and double Brillouin spacing regimes in the proposed setup is less than 1.5 dB throughout a 30 min time span.

  14. Linewidth-narrowed 2-μm single-frequency fiber laser based on stimulated Brillouin scattering effect

    NASA Astrophysics Data System (ADS)

    Fu, Shijie; Shi, Wei; Zhang, Haiwei; Sheng, Quan; Bai, Xiaolei; Yao, Jianquan

    2017-02-01

    A 2-μm linear-polarized single-frequency Brillouin-Thulium fiber laser (BTFL) has been experimentally investigated for linewidth narrowing. The threshold for the Brillouin pump is around 200 mW, and more than 205 mW single-frequency Stokes laser was achieved with the 793 nm pump power of 8.5 W. The linewidth of the fiber laser has been narrowed for 8 times, from 34 to 4.6 kHz. The measured RIN of the BTFL is <-150 dB/Hz for frequency above 2 MHz, which approaches the shot noise limit.

  15. Experimental and numerical study of high order Stokes lines in Brillouin-erbium fiber laser

    SciTech Connect

    Yuan, Yijun; Yao, Yong Xiao, Jun Jun; Yang, Yanfu; Tian, Jiajun; Liu, Chao

    2014-01-28

    We experimentally study the dependences of high-order Stokes lines on the erbium-doped fiber (EDF) pump power P{sub EDF}, the Brillouin pump (BP) power P{sub BP}, and its working wavelength in a multiwavelength Brillouin erbium-doped fiber laser (MBEFL). By using the rate and propagation equations, and the coupled wave equations of stimulated Brillouin scattering, we establish a lumped model to describe the MBEFL. Numerical simulations show that the number of Stokes lines can be increased by decreasing the spacing between the BP wavelength and the EDF peak gain or P{sub BP} as long as it is larger than a critical value P{sub BP}{sup (cr)}=1.7 mW, or by increasing P{sub EDF} without reaching a saturation value P{sub EDF}{sup (cr)}=250 mW. However, when P{sub BP} and P{sub EDF} are varied beyond P{sub BP}{sup (cr)} and P{sub EDF}{sup (cr)}, respectively, the number of Stokes lines is reduced, accompanied by some self-lasing cavity modes. These results by numerical simulation are consistent with experimental observations from the MBEFL.

  16. Experimental and numerical study of high order Stokes lines in Brillouin-erbium fiber laser

    NASA Astrophysics Data System (ADS)

    Yuan, Yijun; Yao, Yong; Xiao, Jun Jun; Yang, Yanfu; Tian, Jiajun; Liu, Chao

    2014-01-01

    We experimentally study the dependences of high-order Stokes lines on the erbium-doped fiber (EDF) pump power PEDF, the Brillouin pump (BP) power PBP, and its working wavelength in a multiwavelength Brillouin erbium-doped fiber laser (MBEFL). By using the rate and propagation equations, and the coupled wave equations of stimulated Brillouin scattering, we establish a lumped model to describe the MBEFL. Numerical simulations show that the number of Stokes lines can be increased by decreasing the spacing between the BP wavelength and the EDF peak gain or PBP as long as it is larger than a critical value PBP(cr)=1.7 mW, or by increasing PEDF without reaching a saturation value PEDF(cr)=250 mW. However, when PBP and PEDF are varied beyond PBP(cr) and PEDF(cr), respectively, the number of Stokes lines is reduced, accompanied by some self-lasing cavity modes. These results by numerical simulation are consistent with experimental observations from the MBEFL.

  17. Brillouin scattering-induced rogue waves in self-pulsing fiber lasers

    PubMed Central

    Hanzard, Pierre-Henry; Talbi, Mohamed; Mallek, Djouher; Kellou, Abdelhamid; Leblond, Hervé; Sanchez, François; Godin, Thomas; Hideur, Ammar

    2017-01-01

    We report the experimental observation of extreme instabilities in a self-pulsing fiber laser under the influence of stimulated Brillouin scattering (SBS). Specifically, we observe temporally localized structures with high intensities that can be referred to as rogue events through their statistical behaviour with highly-skewed intensity distributions. The emergence of these SBS-induced rogue waves is attributed to the interplay between laser operation and resonant Stokes orders. As this behaviour is not accounted for by existing models, we also present numerical simulations showing that such instabilities can be observed in chaotic laser operation. This study opens up new possibilities towards harnessing extreme events in highly-dissipative systems through adapted laser cavity configurations. PMID:28374840

  18. Resonances of pumping and higher stokes components in fiber Brillouin lasers and a method of setting them

    NASA Astrophysics Data System (ADS)

    Spirin, V. V.

    2017-01-01

    An algorithm is presented for setting a fiber Brillouin laser that allows simultaneous provision of the resonance of pumping and higher Stokes components. The proposed radiation source combines a low noise level and low lasing threshold characteristic of double-resonance lasers with the advantages of multifrequency optical emitters.

  19. 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).

  20. Temporal characterization of a multi-wavelength Brillouin-erbium fiber laser

    NASA Astrophysics Data System (ADS)

    Lambin Iezzi, Victor; Büttner, Thomas F. S.; Tehranchi, Amirhossein; Loranger, Sébastien; Kabakova, Irina V.; Eggleton, Benjamin J.; Kashyap, Raman

    2016-05-01

    This paper provides the first detailed temporal characterization of a multi-wavelength-Brillouin-erbium fiber laser (MWBEFL) by measuring the optical intensity of the individual frequency channels with high temporal resolution. It is found that the power in each channel is highly unstable due to the excitation of several cavity modes for typical conditions of operation. Also provided is the real-time measurements of the MWBEFL output power for two configurations that were previously reported to emit phase-locked picosecond pulse trains, concluded from their autocorrelation measurements. Real-time measurements reveal a high degree of instability without the formation of a stable pulse train. Finally, we model the MWBEFL using coupled wave equations describing the evolution of the Brillouin pump, Stokes and acoustic waves in the presence of stimulated Brillouin scattering, and the optical Kerr effect. A good qualitative consistency between the simulation and experimental results is evident, in which the interference signal at the output shows strong instability as well as the chaotic behavior due to the dynamics of participating pump and Stokes waves.

  1. Optimization of output coupling ratio on the performance of a ring-cavity Brillouin-erbium fiber laser.

    PubMed

    Hambali, Nor Azura Malini A; Mahdi, Mohd Adzir; Al-Mansoori, Mohammed Hayder; Saripan, M Iqbal; Abas, Ahmad Fauzi

    2009-09-20

    The operation of a single-wavelength Brillouin-erbium fiber laser (BEFL) system with a Brillouin pump preamplified technique for different output coupling ratios in a ring cavity is experimentally demonstrated. The characteristics of Brillouin Stokes power and tunability were investigated in this research. The efficiency of the BEFL operation was obtained at an optimum output coupling ratio of 95%. By fixing the Brillouin pump wavelength at 1550 nm while its power was set at 1.6 mW and the 1480 pump power was set to its maximum value of 135 mW, the Brillioun Stokes power was found to be 28.7 mW. The Stokes signal can be tuned within a range of 60 nm from 1520 to 1580 nm without appearances of the self-lasing cavity modes in the laser system.

  2. Single-passband microwave photonic filter based on a self-seeded multiwavelength Brillouin-erbium fiber laser

    NASA Astrophysics Data System (ADS)

    Xu, Ronghui; Zhang, Xuping; Hu, Junhui; Xia, Lan

    2015-03-01

    In this paper, a single-passband microwave photonic filter based on a self-seeded multiwavelength Brillouin-erbium fiber laser is demonstrated experimentally. In the filter, the multiwavelength Brillouin comb generated from the laser is used as the filter taps. The Brillouin comb is with the feature of quasi-Gaussian continuous distribution, which can ensure the filter realizes single-passband characteristic. The baseband response is suppressed effectively with the help of phase modulation. The single-passband filter has an out-of-band rejection of 25 dB. By adjusting the Brillouin multiwavelengh, the 3-dB bandwidth and the center frequency of the filter can be changed.

  3. Flat amplitude multiwavelength Brillouin-Raman comb fiber laser in Rayleigh-scattering-enhanced linear cavity.

    PubMed

    Zamzuri, A K; Mahdi, M A; Ahmad, A; Md Ali, M I; Al-Mansoori, M H

    2007-03-19

    We investigate the amplitude flatness of Rayleigh-assisted Brillouin-Raman comb laser in a linear cavity in which feedbacks are formed by high-reflectivity mirror. The optimization of Brillouin pump power and wavelength is very crucial in order to obtain a uniform power level between Stokes lines. The Brillouin pump must have a relatively large power and its wavelength must be located closer to the Raman peak gain region. The flat-amplitude bandwidth is also determined by the choice of Raman pump wavelengths. A flat-amplitude bandwidth of 30.7 nm from 1527.32 to 1558.02 nm is measured when Raman pump wavelengths are set to 1435 and 1450 nm. 357 uniform Brillouin Stokes lines with 0.086 nm spacing are generated across the wavelength range. The average signal-to-noise ratio of 17 dB is obtained for all the Brillouin Stokes lines.

  4. Tunable multiwavelength Brillouin-Raman fiber laser in a linear cavity with spectrum reshaped by Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Wang, Zhen; Wang, Tianshu; Ma, Wanzhuo; Jia, Qingsong; Su, Qingchao; Zhang, Peng

    2017-07-01

    In this paper, we propose and experimentally study a simple linear cavity multiwavelength Brillouin-Raman fiber laser (MBRFL). The fiber feedback loop which consists of an optical circulator is placed at the end of the dispersion compensating fiber (DCF) to enhance the reflectivity of the Brillouin Stokes waves. As a result, 245 Brillouin Stokes lines with 0.072 nm channel-spacing are generated across the wavelength range of 18.6 nm from 1544.98 to 1563.58 nm when Brillouin pump (BP) is fixed to 1545 nm/-2.94 dBm and a single Raman pump (RP) laser power is set to 718 mW. The output spectrum is reshaped based on Rayleigh scattering by adding 45 km single mode fiber (SMF) in the cavity. The average optical signal to noise ratio (OSNR) about 18 dB has been measured in this structure. A tunable multiwavelength range of 20 nm from 1545 to 1565 nm is obtained. We also demonstrate the influence of BP wavelength and power on MBRFL.

  5. Tunable and switchable Brillouin multi-wavelength thulium fluoride fiber laser in S/S+ band region

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Ooi, S. I.; Samion, M. Z.; Jasim, A. A.; Tiu, Z. C.

    2017-08-01

    In this work, a multi-wavelength fiber laser with a channel spacing of 0.17 nm operating in the S-band region is proposed and demonstrated. The proposed laser exploits the stimulated Brillouin scattering (SBS) effect to generate the desired output using a 6.9 km long dispersion shifted fiber. A Thulium-Fluoride fiber (TFF) pumped at 1400 nm enables gain and operation in the S-band region. With a Brillouin pump (BP) wavelength of 1503.6 nm and power of 12 dBm, up to 3 well defined even Stokes lines are obtained at the maximum pump power of 250 mW. Furthermore, more even Stokes lines and anti-Stokes lines are also observed at the afore-mentioned setting, although they are less well defined as the first 3 even Stokes. The laser has an operating range of 1470-1515 nm, with tunability enabled by changing the BP wavelength. Furthermore, the spacing between the lasing wavelengths can be switched from 0.17 nm to 0.08 nm by adjusting the integrated air gap in the laser cavity, making the proposed laser highly suitable for applications such as communications and sensing. This is, the first time to the author's knowledge that such a system has been demonstrated.

  6. Bismuth-based erbium-doped fiber as a gain medium for L-band amplification and Brillouin fiber laser

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Shahi, S.; Harun, S. W.

    2010-03-01

    Bismuth-based erbium-doped fiber (Bi-EDF) is demonstrated as an alternative medium for optical amplification and nonlinear applications. The bismuth glass host provides the opportunity to be doped heavily with erbium ions to allow a compact optical amplifier design. The bismuth-based erbium-doped fiber amplifier (Bi-EDFA) is demonstrated to operate at wavelength region from 1570 to 1620 nm using only a 215 cm long of gain medium. The maximum gain of 15.8 dB is obtained at signal wavelength of 1610 nm with the corresponding noise figure of about 6.3 dB. A multi-wavelength laser comb is also demonstrated using a stimulated Brillouin scattering in the 215 cm long Bi-EDF assisted by the 1480 nm pumping. The laser generates more than 40 lines of optical comb with a line spacing of approximately 0.08 at 1612.5 nm region using 152 mW of 1480 nm pump power.

  7. Stimulated Brillouin Scattering Suppression in Fiber Amplifiers via Chirped Diode Lasers

    DTIC Science & Technology

    2011-09-01

    acousto- optic frequency shifters‡ ( 3 ). Coherent combination of 10 single-mode fiber lasers could then yield a robust, efficient, diffraction-limited 100... kW source. Long-distance fiber telecommunications are also adversely affected by SBS. In this case, the laser cannot be chirped without distorting...in fiber length. 3 1.5µ ChDL AOFS PLL ErFA Figure 1. Chirped diode laser seeding one or more Er fiber amplifiers, each preceded by an AOFS

  8. Multiple Channel Laser Beam Combination and Phasing Using Stimulated Brillouin Scattering in Optical Fibers

    DTIC Science & Technology

    2005-12-01

    light in stimulated Mandel’shtam–Brillouin scattering,” JETP Lett ., 15, 109-112, 1972. 41 . Hellwarth, R. W., “Phase conjugation by stimulated...interferometry with wavefront-reversing mirrors,” Sov . Phys . JETP , 52, 847-851, 1980. 79. Valley, M., G. Lombardi, and R. Aprahamian, “Beam...discharge,” Appl. Phys . Lett ., 86, 111104, 2005. 13. Lange, Mathew A., “Kinetics of the electric discharge pumped oxygen-iodine laser,” Sixth

  9. BOTDA sensing system employing a tunable low-cost Brillouin fiber ring laser pump-probe source

    NASA Astrophysics Data System (ADS)

    Iuliano, M.; Marini, D.; Bastianini, F.; Bolognini, G.

    2017-04-01

    In this paper we show a Brillouin optical time-domain analysis (BOTDA) sensing system experiment employing a tunable narrow-linewidth dual pump-probe source based on modified Brillouin ring laser technology. The developed cost-effective source generates a pump-locked and tunable probe light, with wavelength shift and a large tuning range ( 200 MHz), narrow linewidth (<2.5 MHz) and adequate power ( 0.5 mW). The developed source was hence employed in BOTDA system experiments providing distributed sensing over 10 km single mode optical fiber, and attaining strain and temperature resolutions of 10μɛ and 0.5 °C respectively, indicating the pump-probe source as an efficient and cost-effective solution for BOTDA avoiding high-frequency signal generators or complex locking techniques.

  10. Continues-wave Brillouin-Raman fiber ring laser using 7.7 km long dispersion compensating fiber at 1563 nm wavelength

    NASA Astrophysics Data System (ADS)

    Rizman, Z. I.; Zakaria, U. N.; Latiff, A. A.; Harun, S. W.; Jusoh, Z.

    2017-06-01

    We demonstrate the generation of continues-wave (CW) laser based on Brillouin-Raman fiber laser (BRFL) by incorporating a 7.7 km long dispersion compensating fiber (DCF) as a nonlinear gain medium. The 1455 nm Raman pump (RP) was launched into the DCF via a wavelength division multiplexing (WDM). At 645 mW pump power, stable CW laser presence at 1563.5 nm (1st stokes), 1563.4 (2nd stokes) nm and 1563.3 nm (3rd stokes). Those peak wavelengths have produced most identical output power. This finding proves our ring laser cavity has the capability to generate stable CW BRFL. Thus, it potentially to generate pulse laser operation in the future work.

  11. Novel Optical Fiber Materials With Engineered Brillouin Gain Coefficients SSL 1: Novel Fiber Lasers

    DTIC Science & Technology

    2015-12-29

    the core, its expansion is strongly restricted by the cladding (pure silica) of the fiber, which has a thermal expansion coefficient of 0.54 x 10-6 K... Coefficient (MHz/K) +0.037 TOC (K-1) 1.217 x 10-5 Strain Coefficient (GHz/ε) +16.4 εOC (unitless) 0.115 Δν (MHz) 82.0 ρ (kg/m3)*,** 2944 25 in...to the mode-field diameter (MFD) mismatch between the fibers. Due to its low mass, lithium cannot be detected using energy dispersive X - ray

  12. Temperature sensing using four-wavelength Fabry-Pérot Brillouin-erbium fiber laser by low frequency detection

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Zhang, Mingjiang; Wang, Peng; Zhang, Jianzhong; Wang, Yuncai

    2015-11-01

    A four-wavelength Fabry-Pérot Brillouin-erbium fiber laser (FP-BEFL) with sensing element of 10 m single mode fiber (SMF) and gain media of 6 m erbium-doped fiber (EDF) for temperature measurement is proposed and demonstrated. Stabilization of FP-BEFL is effectively improved by the modified FP structure with a Faraday rotation mirror (FRM). Then, temperature sensitivity of every wavelength is obtained by measuring the beat frequency shift between four-wavelength and reference light. 1.036 MHz/°C, 2.006 MHz/°C and 3.104 MHz/°C temperature elevation coefficient of the different wavelength respectively keep in good agreement with theoretical value. About  ±0.3 dB power fluctuation of different wavelength is achieved by optical spectrum analyzer (OSA) in 1 h. This new configuration has promising applications in temperature sensing with high stabilization, high sensitivity and cost effectiveness.

  13. Stimulated Brillouin scattering in single mode optical fiber

    NASA Astrophysics Data System (ADS)

    Davis, Michael Andrew

    1997-09-01

    This thesis describes a number of experiments that have been performed to study various effects of stimulated Brillouin scattering (SBS) in single mode optical fibers. We have investigated the scattering process by measuring the power limiting effects and increased noise characteristics under different conditions. Additionally, we show a correlation between the relative intensity noise of the Brillouin scattered signal and its spectral bandwidth, which reinforces the theory that spontaneous Brillouin scattering is 'seeded' by random thermal perturbations in the optical fiber. This initial work demonstrates the potentially detrimental effects SBS can have on optical fiber systems. We have therefore also investigated a technique that will suppress the generation of Brillouin scattering. A phase modulation concept is described and the performance of the scheme is demonstrated with Mach-Zehnder interferometric sensors. In addition to the negative effects of SBS, certain aspects of the scattering process, such as the inherent Brillouin gain, can be used in a beneficial manner. We experiment with using the Brillouin scattering gain to produce a ring resonator laser and the generation of multiple laser signals. Furthermore, we demonstrate the use of the SBS gain to sense external strain and temperature perturbations of the optical fiber.

  14. Multiple Channel Laser Beam Combination and Phasing Using Stimulated Brillouin Scattering in Optical Fibers

    DTIC Science & Technology

    2005-12-01

    Mandel’shtam–Brillouin scattering,” JETP Lett ., 15, 109-112, 1972. 41 . Hellwarth, R. W., “Phase conjugation by stimulated backscattering,” ch. 7, Optical...wavefront-reversing mirrors,” Sov . Phys . JETP , 52, 847-851, 1980. 79. Valley, M., G. Lombardi, and R. Aprahamian, “Beam combination by stimulated...Thomas, and R. Byer, Monolithic, “Unidirectional single-mode Nd:YAG ring laser”, Opt. Lett ., 10, 65-67, 1985 . 56. Imai, M. and E. H. Hara

  15. Multiple Channel Laser Beam Combination and Phasing Using Stimulated Brillouin Scattering in Optical Fibers

    DTIC Science & Technology

    2005-12-22

    Mandel’shtam–Brillouin scattering,” JETP Lett ., 15, 109-112, 1972. 41 . Hellwarth, R. W., “Phase conjugation by stimulated backscattering,” ch. 7, Optical...wavefront-reversing mirrors,” Sov . Phys . JETP , 52, 847-851, 1980. 79. Valley, M., G. Lombardi, and R. Aprahamian, “Beam combination by stimulated...Thomas, and R. Byer, Monolithic, “Unidirectional single-mode Nd:YAG ring laser”, Opt. Lett ., 10, 65-67, 1985 . 56. Imai, M. and E. H. Hara

  16. Dynamic characteristics of a multi-wavelength Brillouin-Raman fiber laser assisted by multiple four-wave mixing processes in a ring cavity

    NASA Astrophysics Data System (ADS)

    Shirazi, M. R.; Mohamed Taib, J.; De La Rue, R. M.; Harun, S. W.; Ahmad, H.

    2015-03-01

    Dynamic characteristics of a multi-wavelength Brillouin-Raman fiber laser (MBRFL) assisted by four-wave mixing have been investigated through the development of Stokes and anti-Stokes lines under different combinations of Brillouin and Raman pump power levels and different Raman pumping schemes in a ring cavity. For a Stokes line of order higher than three, the threshold power was less than the saturation power of its last-order Stokes line. By increasing the Brillouin pump power, the nth order anti-Stokes and the (n+4)th order Stokes power levels were unexpectedly increased almost the same before the Stokes line threshold power. It was also found out that the SBS threshold reduction (SBSTR) depended linearly on the gain factor for the 1st and 2nd Stokes lines, as the first set. This relation for the 3rd and 4th Stokes lines as the second set, however, was almost linear with the same slope before SBSTR -6 dB, then, it approached to the linear relation in the first set when the gain factor was increased to 50 dB. Therefore, the threshold power levels of Stokes lines for a given Raman gain can be readily estimated only by knowing the threshold power levels in which there is no Raman amplification.

  17. Multi-band multiwavelength fiber laser based on the combined effects of four wave mixing and self-seeding stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Yuan, Yijun; Yi, Miao; Yao, Yong

    2017-07-01

    A multi-band multiwavelength erbium-doped fiber laser (MBMEFL) based on the combined four wave mixing effect (FWM) and self-seeding stimulated Brillouin scattering (SSBS) effect has been studied experimentally. We use two ring cavities which consist of a large and a small cavity to build up this MBMEFL. The output multiple bands and multiple wavelengths are depended on the EDFA power and the length of the single mode fiber (SMF). With a proper length of SMF, we can achieve multi-band lasing by FWM effect and multiwavelength lasing in these bands by SSBS. By increasing the EDFA power, the multi-band multiwavelength lasing signals from the MBMEFL decrease.

  18. Generation of efficient 33 GHz optical combs using cascaded stimulated Brillouin scattering effects in optical fiber

    NASA Astrophysics Data System (ADS)

    Al-Mansoori, M. H.; Al-Sheriyani, A.; Al-Nassri, S.; Hasoon, F. N.

    2017-06-01

    In this paper, we demonstrate a multi-wavelength Brillouin-erbium fiber laser (BEFL) with ~33 GHz frequency spacing using cascaded stimulated Brillouin scattering effects in optical fiber. The proposed laser structure exhibits a stable output channel with a tuning range of 19 nm, from 1549 nm to 1568 nm. The number of stable output channels produced is six channels with a triple-Brillouin frequency spacing. The output channels exhibit high output power and high optical signal-to-noise ratios (OSNRs). The laser structure has the potential to be used as a multi-wavelength source for optical communication systems.

  19. Brillouin optical fiber sensor for cryogenic thermometry

    NASA Astrophysics Data System (ADS)

    Thevenaz, Luc; Fellay, Alexandre; Facchini, Massimo; Scandale, Walter; Nikles, Marc; Robert, Philippe A.

    2002-07-01

    Supraconductive installations are now commonly used in large facilities, such as power plants and particle accelerators. This requires a permanent temperature control at very low temperature, but cryogenic temperature measurements in the 1-77K range requires expensive calibrated temperature probes. We report here the possibility to use stimulated Brillouin scattering in optical fibers for temperature sensing down to 1K. Such a technique offers the additional advantage to make possible distributed measurement, so that very large structures and systems can be controlled using a single fiber and a single analyzing instrument. In addition only one by-pass for the fiber is required as input to the cryogenic vessel, that is definitely a key advantage for the design and the energy loss. Brillouin scattering in optical fibers has never been investigated so far at temperature below 77K (nitrogen boiling point). This absence of interest probably results from the constant decrease of scattering efficiency that was observed while cooling the fiber down to 77K. Our measurements show the unexpected feature that scattering efficiency is significantly raised below 50K and is even much better than observed at room temperature. The relevance and the feasibility of the technique is demonstrated in real scale on the supraconductive magnets for the future world largest particle accelerator, namely the large hadron collider (LHC) at CERN Laboratory in Geneva.

  20. Photonic crystal fiber mapping using Brillouin echoes distributed sensing.

    PubMed

    Stiller, B; Foaleng, S M; Beugnot, J-C; Lee, M W; Delqué, M; Bouwmans, G; Kudlinski, A; Thévenaz, L; Maillotte, H; Sylvestre, T

    2010-09-13

    In this paper we investigate the effect of microstructure irregularities and applied strain on backward Brillouin scattering by comparing two photonic crystal fibers drawn with different parameters in order to minimize diameter and microstructure fluctuations. We fully characterize their Brillouin properties including the gain spectrum and the critical power. Using Brillouin echoes distributed sensing with a high spatial resolution of 30 cm we are able to map the Brillouin frequency shift along the fiber and get an accurate estimation of the microstructure longitudinal fluctuations. Our results reveal a clear-cut difference of longitudinal homogeneity between the two fibers.

  1. Characterized Brillouin scattering in silica optical fiber tapers based on Brillouin optical correlation domain analysis.

    PubMed

    Zou, Weiwen; Jiang, Wenning; Chen, Jianping

    2013-03-11

    This paper demonstrates stimulated Brillouin scattering (SBS) characterization in silica optical fiber tapers drawn from commercial single mode optical fibers by hydrogen flame. They have different waist diameters downscaled from 5 μm to 42 μm. The fully-distributed SBS measurement along the fiber tapers is implemented by Brillouin optical correlation domain analysis technique with millimeter spatial resolution. It is found that the Brillouin frequency shift (BFS) in the waist of all fiber tapers is approximately the same (i.e., ~11.17 GHz at 1550 nm). However, the BFS is gradually reduced and the Brillouin gain decreases from the waist to the untapered zone in each fiber taper.

  2. Stimulated Brillouin scattering suppression of thulium-doped fiber amplifier with fiber superfluorescent seed source.

    PubMed

    Liu, Chen; Liu, Jiang; Zhang, Yijing; Hou, Yubin; Qi, Shuxian; Feng, Xian; Wang, Pu

    2017-05-01

    We investigate the stimulated Brillouin scattering (SBS) effect in high-power thulium-doped fiber amplifier seeded with a narrow-linewidth fiber superfluorescent source or a conventional narrow-linewidth fiber laser. No random backward SBS pulses are observed when using a narrow-linewidth fiber superfluorescent source as the seed. The corresponding average power and peak power reach 153 W and 3.4 kW, respectively, only limited by the available pump power. This gives the average power and peak power extraction from the thulium-doped fiber amplifier with 17 fold enhancement, in comparison with the situation using the conventional narrow-linewidth fiber laser with similar central wavelength and spectral linewidth as the seed. This work indicates that using low coherent fiber superfluorescent sources is a good solution for power scaling in narrow-linewidth fiber amplifier system in order to overcome the limitation of SBS effect.

  3. Toward investigation of Brillouin scattering in multimode polymer and silica optical fibers

    NASA Astrophysics Data System (ADS)

    Wosniok, Aleksander; Schreier, Andy

    2017-05-01

    In this paper, we present a study aimed at characterizing the optimal fiber optic components for Brillouin sensing in multimode fibers. For this purpose the use of single-mode and multimode circulators as well as couplers typically used in the Brillouin measurement setups was investigated. On the one hand the undesired coupling losses between conventional fiber optic measurement system components and a multimode sensor fiber can be overcome by replacing the singlemode components with their own multimode equivalents. On the other hand the use of multimode fiber optic circulators and multimode couplers affects the mode distribution of laser light which can impair the measurement signal backscattered in the multimode sensor fibers. In view of an increasing interest in high strain measurements using polymer optical fibers (POFs) as Brillouin-distributed sensors the investigation on Brillouin scattering effects in multimode fibers (MMFs) was performed on a low-loss perfluorinated graded-index polymer optical fiber (PFGI-POF). The obtained results were compared with those of a standard graded-index multimode (GI-MMF) silica glass optical fiber (GOF). This study confirms the relevance of the adaptation of the measurement system components to the use of the multimode sensor fibers. In addition, due to mode coupling effects occurring in the tested POF itself, the results show differences in the yield of the components adaptation in the sensory implementation of the two kinds of the tested optical fibers.

  4. Characterization of a high coherence, Brillouin microcavity laser on silicon.

    PubMed

    Li, Jiang; Lee, Hansuek; Chen, Tong; Vahala, Kerry J

    2012-08-27

    Recently, a high efficiency, narrow-linewidth, chip-based stimulated Brillouin laser (SBL) was demonstrated using an ultra-high-Q, silica-on-silicon resonator. In this work, this novel laser is more fully characterized. The Schawlow Townes linewidth formula for Brillouin laser operation is derived and compared to linewidth data, and the fitting is used to measure the mechanical thermal quanta contribution to the Brillouin laser linewidth. A study of laser mode pulling by the Brillouin optical gain spectrum is also presented, and high-order, cascaded operation of the SBL is demonstrated. Potential application of these devices to microwave sources and phase-coherent communication is discussed.

  5. Fiber optic distributed temperature and strain sensing system based on Brillouin light scattering.

    PubMed

    Chang, Tianying; Li, David Y; Koscica, Thomas E; Cui, Hong-Liang; Sui, Qingmei; Jia, Lei

    2008-11-20

    We present an original method to improve the spatial resolution of a Brillouin distributed temperature and strain sensing system (DTSS). This method is shown to substantially improve the spatial resolution, while simultaneously strengthening the Brillouin backscattered light, which is based on the combination of an internal modulation of the laser source and an external modulator to generate two separate light pulses with different central wavelengths and pulse widths. Moreover, a novel Brillouin signal detection method, which we called isogenous heterodyne detection, is introduced, which is equivalent to a heterodyne detection scheme but is only with Rayleigh and Brillouin backscattered light without the need of an extra reference light. These new technical approaches have been incorporated into a fiber optic DTSS with 13 km single-mode fiber, which clearly successfully demonstrated all the advantages over conventional DTSS approaches in theory and the feasibility in experiment.

  6. Refractive index fiber sensor based on Brillouin fast light

    NASA Astrophysics Data System (ADS)

    Chen, Jiali; Gan, Jiulin; Zhang, Zhishen; Yang, Tong; Deng, Huaqiu; Yang, Zhongmin

    2014-01-01

    A new type of refractive index fiber sensor was invented by combining the evanescent-field scattering sensing mechanism with the Brillouin fast light scheme. Superluminal light was realized using Brillouin lasing oscillation in a fiber ring cavity. The refractive index of the solution around the microfiber within the cavity is related to the group velocity of the fast light. This fast light refractive index sensor offers an alternative for high-accuracy sensing applications.

  7. Particle swarm optimization on threshold exponential gain of stimulated Brillouin scattering in single mode fibers.

    PubMed

    Al-Asadi, H A; Al-Mansoori, M H; Hitam, S; Saripan, M I; Mahdi, M A

    2011-01-31

    We implement a particle swarm optimization (PSO) algorithm to characterize stimulated Brillouin scattering phenomena in optical fibers. The explicit and strong dependence of the threshold exponential gain on the numerical aperture, the pump laser wavelength and the optical loss coefficient are presented. The proposed PSO model is also evaluated with the localized, nonfluctuating source model and the distributed (non-localized) fluctuating source model. Using our model, for fiber lengths from 1 km to 29 km, the calculated threshold exponential gain of stimulated Brillouin scattering is gradually decreased from 17.4 to 14.6 respectively. The theoretical results of Brillouin threshold power predicted by the proposed PSO model show a good agreement with the experimental results for different fiber lengths from 1 km to 12 km.

  8. Stimulated Brillouin Scattering (SBS) Suppression and Long Delivery Fibers at the Multikilowatt Level with Chirped Seed Lasers

    DTIC Science & Technology

    2017-03-16

    Mark Harfouche and Amnon Yariv Department of Electrical Engineering , California Institute of Technology, Pasadena, CA John Edgecumbe Nufern...external mirror of a vertical cavity surface - emitting diode laser 0.2 µm in 10 µs can yield a frequency chirp of 5 × 1017 Hz/s at a nearly constant...Burgner for providing the microelectromechanical system (MEMS)-vertical-cavity, surface - emitting lasers (VCSELs). This work was supported by the High

  9. Polarization dependence of Brillouin linewidth and peak frequency due to fiber inhomogeneity in single mode fiber and its impact on distributed fiber Brillouin sensing.

    PubMed

    Xie, Shangran; Pang, Meng; Bao, Xiaoyi; Chen, Liang

    2012-03-12

    The dependence of Brillouin linewidth and peak frequency on lightwave state of polarization (SOP) due to fiber inhomogeneity in single mode fiber (SMF) is investigated by using Brillouin optical time domain analysis (BOTDA) system. Theoretical analysis shows fiber inhomogeneity leads to fiber birefringence and sound velocity variation, both of which can cause the broadening and asymmetry of the Brillouin gain spectrum (BGS) and thus contribute to the variation of Brillouin linewidth and peak frequency with lightwave SOP. Due to fiber inhomogeneity both in lateral profile and longitudinal direction, the measured BGS is the superposition of several spectrum components with different peak frequencies within the interaction length. When pump or probe SOP changes, both the peak Brillouin gain and the overlapping area of the optical and acoustic mode profile that determine the peak efficiency of each spectrum component vary within the interaction length, which further changes the linewidth and peak frequency of the superimposed BGS. The SOP dependence of Brillouin linewidth and peak frequency was experimentally demonstrated and quantified by measuring the spectrum asymmetric factor and fitting obtained effective peak frequency respectively via BOTDA system on standard step-index SMF-28 fiber. Experimental results show that on this fiber the Brillouin spectrum asymmetric factor and effective peak frequency vary in the range of 2% and 0.06MHz respectively over distance with orthogonal probe input SOPs. Experimental results also show that in distributed fiber Brillouin sensing, polarization scrambler (PS) can be used to reduce the SOP dependence of Brillouin linewidth and peak frequency caused by fiber inhomogeneity in lateral profile, however it maintains the effects caused by fiber inhomogeneity in longitudinal direction. In the case of non-ideal polarization scrambling using practical PS, the fluctuation of effective Brillouin peak frequency caused by fiber inhomogeneity

  10. Recent Progress in Brillouin Scattering Based Fiber Sensors

    PubMed Central

    Bao, Xiaoyi; Chen, Liang

    2011-01-01

    Brillouin scattering in optical fiber describes the interaction of an electro-magnetic field (photon) with a characteristic density variation of the fiber. When the electric field amplitude of an optical beam (so-called pump wave), and another wave is introduced at the downshifted Brillouin frequency (namely Stokes wave), the beating between the pump and Stokes waves creates a modified density change via the electrostriction effect, resulting in so-called the stimulated Brillouin scattering. The density variation is associated with a mechanical acoustic wave; and it may be affected by local temperature, strain, and vibration which induce changes in the fiber effective refractive index and sound velocity. Through the measurement of the static or dynamic changes in Brillouin frequency along the fiber one can realize a distributed fiber sensor for local temperature, strain and vibration over tens or hundreds of kilometers. This paper reviews the progress on improving sensing performance parameters like spatial resolution, sensing length limitation and simultaneous temperature and strain measurement. These kinds of sensors can be used in civil structural monitoring of pipelines, bridges, dams, and railroads for disaster prevention. Analogous to the static Bragg grating, one can write a moving Brillouin grating in fibers, with the lifetime of the acoustic wave. The length of the Brillouin grating can be controlled by the writing pulses at any position in fibers. Such gratings can be used to measure changes in birefringence, which is an important parameter in fiber communications. Applications for this kind of sensor can be found in aerospace, material processing and fine structures. PMID:22163842

  11. Recent progress in Brillouin scattering based fiber sensors.

    PubMed

    Bao, Xiaoyi; Chen, Liang

    2011-01-01

    Brillouin scattering in optical fiber describes the interaction of an electro-magnetic field (photon) with a characteristic density variation of the fiber. When the electric field amplitude of an optical beam (so-called pump wave), and another wave is introduced at the downshifted Brillouin frequency (namely Stokes wave), the beating between the pump and Stokes waves creates a modified density change via the electrostriction effect, resulting in so-called the stimulated Brillouin scattering. The density variation is associated with a mechanical acoustic wave; and it may be affected by local temperature, strain, and vibration which induce changes in the fiber effective refractive index and sound velocity. Through the measurement of the static or dynamic changes in Brillouin frequency along the fiber one can realize a distributed fiber sensor for local temperature, strain and vibration over tens or hundreds of kilometers. This paper reviews the progress on improving sensing performance parameters like spatial resolution, sensing length limitation and simultaneous temperature and strain measurement. These kinds of sensors can be used in civil structural monitoring of pipelines, bridges, dams, and railroads for disaster prevention. Analogous to the static Bragg grating, one can write a moving Brillouin grating in fibers, with the lifetime of the acoustic wave. The length of the Brillouin grating can be controlled by the writing pulses at any position in fibers. Such gratings can be used to measure changes in birefringence, which is an important parameter in fiber communications. Applications for this kind of sensor can be found in aerospace, material processing and fine structures.

  12. Stimulated Brillouin Scattering Phase Conjugation in Fiber Optic Waveguides

    DTIC Science & Technology

    2008-07-01

    States Air Force, Department of Defense, or the United States Government AFIT/DS/ENP/08-S03 STIMULATED BRILLOUIN SCATTERING PHASE...The logistics burden of chemical lasers has prompted the DoD to develop solid- state lasers for high-power applications such as the 100 kW Joint High...Power Solid- State Laser program. For the success of laser weapons, the high power laser is needed in addition to advanced beam control and

  13. Pulse width dependence of Brillouin frequency in single mode optical fibers.

    PubMed

    Cho, Seok-Beom; Kim, Young-Gyu; Heo, Jin-Seok; Lee, Jung-Ju

    2005-11-14

    Stimulated Brillouin scattering in optical fibers can be used to measure strain or temperature in a distributed manner. Brillouin optical time domain analysis (BOTDA) is the most common sensor system based on the Brillouin scattering. This paper presents the experimental analysis of the characteristics of Brillouin gain spectrum (BGS) influenced by the width of launched pulse. Brillouin strain coefficient is also examined for the different pulse widths, which is important to apply a Brillouin scattering-based sensor to a structural health monitoring. Experimental results showed that not only the Brillouin linewidth and gain but also the Brillouin frequency were dependent on the pulse widths.

  14. Influence of laser phase noise on Brillouin optical time-domain analysis sensors

    NASA Astrophysics Data System (ADS)

    Minardo, A.; Zeni, L.

    2016-05-01

    This paper presents a numerical study of the phase noise from the laser in Brillouin Optical Time-Domain analysis (BOTDA) sensors. Due to laser phase noise, the phase shift cumulated by pump and probe beams during interaction in a generic fiber position is a stochastic variable, with zero mean and variance increasing with pulse duration. For negligibly small pulse leakage, the induced noise is independent of fiber length; otherwise, it increases with fiber length as long as the laser coherence length is longer than fiber.

  15. High-power pulsed thulium fiber oscillator modulated by stimulated Brillouin scattering

    SciTech Connect

    Tang, Yulong Xu, Jianqiu

    2014-01-06

    A pulsed ∼2-μm thulium-doped fiber laser passively modulated by distributed stimulated Brillouin scattering achieves 10.2 W average power and >100 kHz repetition rate with a very simple all-fiber configuration. The maximum pulse energy and peak power surpass 100 μJ and 6 kW, respectively. Another distinct property is that the pulse width is clamped around 17 ns at all power levels. All the average-power, pulse energy, and peak power show the highest values from passively modulated fiber lasers in all wavelength regions.

  16. Complete experimental characterization of stimulated Brillouin scattering in photonic crystal fiber.

    PubMed

    Beugnot, J C; Sylvestre, T; Alasia, D; Maillotte, H; Laude, V; Monteville, A; Provino, L; Traynor, N; Mafang, S Foaleng; Thévenaz, L

    2007-11-12

    We provide a complete experimental characterization of stimulated Brillouin scattering in a 160 m long solid-core photonic crystal fiber, including threshold and spectrum measurements as well as position-resolved mapping of the Brillouin frequency shift. In particular, a three-fold increase of the Brillouin threshold power is observed, in excellent agreement with the spectrally-broadened Brillouin gain spectrum. Distributed measurements additionally reveal that the rise of the Brillouin threshold results from the broadband nature of the gain spectrum all along the fiber and is strongly influenced by strain. Our experiments confirm that these unique fibers can be exploited for the passive control or the suppression of Brillouin scattering.

  17. Narrow linewidth Brillouin laser based on chalcogenide photonic chip.

    PubMed

    Kabakova, Irina V; Pant, Ravi; Choi, Duk-Yong; Debbarma, Sukhanta; Luther-Davies, Barry; Madden, Stephen J; Eggleton, Benjamin J

    2013-09-01

    We present, to the best of our knowledge, the first demonstration of a narrow linewidth, waveguide-based Brillouin laser that is enabled by large Brillouin gain of a chalcogenide chip. The waveguides are equipped with vertical tapers for low-loss coupling. Due to optical feedback for the Stokes wave, the lasing threshold is reduced to 360 mW, which is five times lower than the calculated single-pass Brillouin threshold for the same waveguide. The slope efficiency of the laser is found to be 30%, and the linewidth of 100 kHz is measured using a self-heterodyne method.

  18. Characteristics of the Brillouin spectra in Erbium-Ytterbium fibers.

    PubMed

    Canat, G; Durécu, A; Lesueur, G; Lombard, L; Bourdon, P; Jolivet, V; Jaouën, Y

    2008-03-03

    This paper reports the main characteristics of the Stokes spectra for typical pumped and unpumped Erbium-Ytterbium doped fibers. Doped fibers show shorter Brillouin shifts and their spectra are up to 1.6 times broader than undoped fibers. Those spectra are composed of several peaks originating from several longitudinal acoustic modes. The effective Brillouin gain of the secondary modes can be as large as 20% of the main peak gain. They can merge into a more complex structure for the largest cores. Simulations allow to relate these characteristics to the influence of codoping and index profile inhomogeneity. An additional broadening of the Stokes spectrum in pumped fibers is reported and attributed to thermal effects.

  19. Self-pulsation threshold of Raman amplified Brillouin fiber cavities.

    PubMed

    Ott, J R; Pedersen, M E V; Rottwitt, K

    2009-08-31

    An implicit equation for the oscillation threshold of stimulated Brillouin scattering from Raman amplified signals in fibers with external feedback is derived under the assumption of no depletion. This is compared to numerical investigations of Raman amplification schemes showing good agreement for high reflectivities. For low reflectivities and high attenuation or long fibers, the assumption of no depletion is shown not to be valid. In these cases the effects of the depletion on the self-pulsation is examined.

  20. Characterization of Brillouin dynamic grating based on chaotic laser

    NASA Astrophysics Data System (ADS)

    Zhang, Jianzhong; Li, Zhuping; Zhang, Mingjiang; Liu, Yi; Li, Yang

    2017-08-01

    The Brillouin dynamic grating (BDG) based on chaotic laser has particular advantages over the conventional BDG, for example, the creation of single and permanent BDG. To gain insight into the chaotic BDG, we theoretically investigate the reflection and gain spectra characteristics of the chaotic BDG generated in the polarization maintaining fiber. We find that the reflection spectral width of the chaotic BDG is inversely proportional to the effective grating length and the variation in the gain spectral width is negligible with respect to the effective grating length. The widths of the reflection and gain spectra are not affected by the power of the chaotic pump wave. Besides, we analyze that the occurrence of the weak BDG in the generation process of the chaotic BDG leads to the side-lobe of the reflected pulse.

  1. One-laser-based generation/detection of Brillouin dynamic grating and its application to distributed discrimination of strain and temperature.

    PubMed

    Zou, Weiwen; He, Zuyuan; Hotate, Kazuo

    2011-01-31

    This paper presents a novel scheme to generate and detect Brillouin dynamic grating in a polarization-maintaining optical fiber based on one laser source. Precise measurement of Brillouin dynamic grating spectrum is achieved benefiting from that the pump, probe and readout waves are coherently originated from the same laser source. Distributed discrimination of strain and temperature is also achieved with high accuracy.

  2. Efficient dynamic events discrimination technique for fiber distributed Brillouin sensors.

    PubMed

    Galindez, Carlos A; Madruga, Francisco J; Lopez-Higuera, Jose M

    2011-09-26

    A technique to detect real time variations of temperature or strain in Brillouin based distributed fiber sensors is proposed and is investigated in this paper. The technique is based on anomaly detection methods such as the RX-algorithm. Detection and isolation of dynamic events from the static ones are demonstrated by a proper processing of the Brillouin gain values obtained by using a standard BOTDA system. Results also suggest that better signal to noise ratio, dynamic range and spatial resolution can be obtained. For a pump pulse of 5 ns the spatial resolution is enhanced, (from 0.541 m obtained by direct gain measurement, to 0.418 m obtained with the technique here exposed) since the analysis is concentrated in the variation of the Brillouin gain and not only on the averaging of the signal along the time. © 2011 Optical Society of America

  3. Simplified correlation-domain Brillouin sensor using plastic optical fiber

    NASA Astrophysics Data System (ADS)

    Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2015-07-01

    To perform distributed strain and temperature measurement, we have recently developed simplified Brillouin optical correlation-domain reflectometry (S-BOCDR), in which the light Fresnel-reflected at the ends of the fiber under test (FUT) is used as a reference light. Here, we implement S-BOCDR using a plastic optical fiber (POF) as an FUT, which provides the following advantages over S-BOCDR using a standard silica single-mode fiber (SMF): (1) the beat signal of the Stokes light and the Fresnel-reflected light that is obtained at the interface between the POF and the SMF (the pigtail of an optical circulator) can be stabilized, and (2) the effect of the 0th correlation peak can be easily and effectively suppressed by exploiting a so-called Brillouin frequency shift-hopping phenomenon. We then experimentally demonstrate a distributed measurement and detect a 0.46-m-long heated POF section.

  4. Pulse shape effects on the measurement of temperature using a Brillouin-based optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Galindez, Carlos; Madruga, Francisco-Javier; Cobo, Adolfo; Conde, Olga; Lopez-Higuera, Jose-Miguel

    2007-04-01

    Distributed fiber sensing based on Brillouin gain scattering (BGS) principle is a useful way to develop devices capable to measure temperature or/and strain in optical fibers. New effects or technologies that could achieve a larger distance and/or a better spatial resolution are a topic of special interest in this fiber sensing area. The influence of the probe-pulse shape in the interaction between the pulsed light and the continuous wave laser in a pump-probe system is presented. The purpose of this study is to improve the spatial resolution of the measurement without losing stability in the BGS. Also it is showed how the backscattering Brillouin gain is affected by inducing variations on the final value of the BGS intensity; this effect is illustrated by using an experimental set up based on the Brillouin optical time-domain analysis (BOTDA). Theoretical analysis of the probe pulse in the Brillouin shift and intensity value using triangular, sinc and saw tooth shapes around the medium phonon life time (~10ns) are presented; as well as the experimental results and possible applications are explained.

  5. Cooperative stimulated Brillouin and Rayleigh backscattering process in optical fiber.

    PubMed

    Fotiadi, A A; Kiyan, R V

    1998-12-01

    We observed an unusually narrow spectrum of Stokes field and Gaussian statistics of Stokes power for the stimulated Brillouin scattering (SBS) process in 300-m single-mode optical fiber with high Rayleigh losses. The measured characteristics of the Stokes radiation indicate that SBS lasing took place in the fiber. The effect is explained as the result of dynamic distributed feedback that is due to double Rayleigh scattering (RS) of the Stokes field. The results of numerical simulation of the cooperative SBS-RS process in fiber are in good agreement with experimental results.

  6. Broadband Brillouin Scatter from CO2-Laser-Target Interactions

    NASA Astrophysics Data System (ADS)

    Mitchel, G. R.; Grek, B.; Johnston, T. W.; Pépin, H.; Church, P.; Lavigne, P.; Martin, F.; Décoste, R.

    1982-05-01

    Light scattered near the incident wavelength from CO2 laser-solid target interactions in oblique incidence shows the spectral signature of Brillouin scattering both in the backward and in the near specular directions. This instability is apparently seeded by broadband scatter from the critical density surface and then amplified in the underdense plasma. 60% of the incident light is scattered, and the Brillouin contribution to total scatter may be large if the source is also large.

  7. An ameliorative technique for distributed Brillouin-based fiber optics sensing

    NASA Astrophysics Data System (ADS)

    Yang, Xing-hong; Li, Yong-qian; Yang, Zhi; Yoshino, Toshihiko

    2008-12-01

    This paper reports an ameliorative technique for distributed fiber optics sensing based on Brillouin optical time-domain reflectometry (BOTDR) and Brillouin optical-fiber time-domain analysis (BOTDA). Because the electro-optic modulator in BOTDR system has a finite extinction ratio, the pulsed laser always contains a CW component, which is hereafter called leakage. The frequency of the leakage is pv which is the same as that of the pulse, and the frequency of the Stokes wave is sv. The frequency of the acoustic wave bv at each point along the fiber matches the beat frequency of the leakage and the Stokes wave. As a result, when given an appropriate extinction ratio, the leakage will have a biggish effect on the Stokes wave, which is the same as the function between the continuous wave and the Stokes in BOTDA system. The Stokes component in spontaneous Brillouin scattering (SPBS) is amplified by the leakage along the distance when it backs to the laser end, which is the well known stimulated Brillouin scattering (SBS) phenomena. So long as the distance from the point where the SPBS engender to the laser end is long, the intensity of the SBS signal is relatively large owing to the longer amplified interval. In BOTDR system, when setting the extinction ratio at 20dB, using the SBS signal we can achieve a SNR which is approximately 5 dB greater than that of traditional system and the dynamic range performance 3 dB greater. Utilizing this new technique in BOTDR system it also has an ascendency compared with BOTDA system in respect that it access to only one end of the fiber with probe pulse light.

  8. Forward cascaded stimulated Brillouin scattering (SBS) in an S-band distributed G652 fiber Raman amplifier

    NASA Astrophysics Data System (ADS)

    Zhang, Zaixuan; Li, Laixiao; Geng, Dan; Liu, Honglin; Jin, Yongxing; Kim, Insoo S.; Wang, Jianfeng; Wu, Xiaobiao; Fang, Dawei; Zhuang, Songlin

    2005-01-01

    The cascaded forward stimulated Brillouin scattering (SBS) in the S band distributed G652 fiber Raman amplifier forward pumped and backward pumped by the tunable power fiber laser and signal source is a tunable narrow spectral bandwidth(<100MHz)ECL have been studied. Forward SBS does not obey the common theory, that only weaken backward-SBS lines existed, according to conservation of energy and momentum and wave vector selected rule. Because the wave-guide character weaken the wave vector rule. The forward transmit sound wave-guide Brillouin scattering lines are generated and amplified in FRA. Forward SBS that is amplified phenomena of transmit sound wave Brillouin scattering in the FRA, during pump power is larger than the threshold value of SBS in a S band G652 FRA. The 2 orders Stokes forward Brillouin lines are present during forward pump power of FRA is 920mW, the pump power of BP line is 7.7dBm and the FRA gain is 15.05dB, the power of first order Brillouin lines is smaller than the second Brillouin scattering line. When pump power is further increased, cascaded SBS lines and comb profile are observed. The even order SBS lines is stronger than odd order SBS lines, The odd order SBS lines are named Brillouin- Rayleigh scattering lines.

  9. Probing axial orientation of collagen fibers with Brillouin microspectroscopy

    NASA Astrophysics Data System (ADS)

    Meng, Zhaokai; Yakovlev, Vladislav V.

    2015-03-01

    Collagen is an important structural component in many biological tissues including bone, teeth, skin, and vascular endothelial layer. Its fibrillar arrangement can produce tissues with distinct anisotropies and is responsible for its unique elastic properties. However, current methods of retrieving orientation of those fibers show low sensitivity to the out-of-plane orientations. In this report, we employed Brillouin microspectroscopy to probe the local sound velocity, which, in its turn, is found to have a strong correlation to the local fibrillar arrangements.

  10. Energetic radiation influence on temperature dependency of Brillouin frequency in optical fibers

    SciTech Connect

    Pheron, X.; Ouerdane, Y.; Delepine-Lesoille, S.; Boukenter, A.; Bertrand, J.

    2011-07-01

    We present a post mortem study of the influence of energetic radiation on optical fiber Brillouin sensors, both Brillouin spectrum and its temperature dependency in two different fibers, a photosensitive optical fiber and a SMF28. The target application is nuclear wastes repository monitoring where optical fiber Brillouin sensors might be exposed to energetic radiation. UV exposure induced optical losses, Brillouin frequency shifts up to 28 MHz and even a variation of the temperature dependency. The photosensitive optical fiber resulted more sensitive than SMF28{sup TM}. (authors)

  11. Stimulated Brillouin scattering in ultra-long distributed feedback Bragg gratings in standard optical fiber.

    PubMed

    Loranger, Sébastien; Lambin-Iezzi, Victor; Wahbeh, Mamoun; Kashyap, Raman

    2016-04-15

    Distributed feedback (DFB) fiber Bragg gratings (FBG) are widely used as narrow-band filters and single-mode cavities for lasers. Recently, a nonlinear generation has been shown in 10-20 cm DFB gratings in a highly nonlinear fiber. First, we show in this Letter a novel fabrication technique of ultra-long DFBs in a standard fiber (SMF-28). Second, we demonstrate nonlinear generation in such gratings. A particular inscription technique was used to fabricate all-in-phase ultra-long FBG and to implement reproducible phase shift to form a DFB mode. We demonstrate stimulated Brillouin scattering (SBS) emission from this DFB mode and characterize the resulting laser. It seems that such a SBS based DFB laser stabilizes a pump's jittering and reduces its linewidth.

  12. Self-referenced and single-ended method to measure Brillouin gain in monomode optical fibers.

    PubMed

    Lanticq, Vincent; Jiang, Shifeng; Gabet, Renaud; Jaouën, Yves; Taillade, Frédéric; Moreau, Gautier; Agrawal, Govind P

    2009-04-01

    We present a new self-referenced and single-ended method to measure the Brillouin-gain coefficient in monomode optical fibers accurately with high reliability. Our comparative measurements on several different fibers show that a fiber with a smaller optical effective mode area can nevertheless have a higher Brillouin threshold, thus confirming the significance of acousto-optic effective mode area.

  13. Sweep-free brillouin optical time domain analysis using two individual laser sources

    NASA Astrophysics Data System (ADS)

    Tsuji, Kenichiro; Noda, Hitoshi; Onodera, Noriaki

    2012-11-01

    We propose a sweep-free measurement technique for distributed Brillouin frequency shift in optical fibers applicable to distributed strain/temperature monitoring systems, using two sets of pump-probe lights generated by two individual laser sources. This technique utilizes the Brillouin gain ratio measured at both the upper and lower side slopes of two different Brillouin spectra induced by two pump lights with different wavelengths. The proposed method offers high-speed measurement due to the combination of the frequency-sweep-free operation and the polarization-insensitive measurement scheme without polarization scramblers. A measurement accuracy of 17.3 μ ɛ with a spatial resolution of 5m over 2.6 km sensing length and a capability of kHz sampling rate are experimentally demonstrated.

  14. Stimulated Brillouin scattering in single-frequency fiber amplifiers with delivery fibers.

    PubMed

    Liu, Anping

    2009-08-17

    For an all-fiber-based single-frequency amplifier, a passive delivery fiber carrying the amplified signal out of the pump combiner may induce unwanted stimulated Brillouin scattering (SBS) and affect amplifier performance. To evaluate the impact, a rate-equation based model has been adopted to study SBS characteristics in the fiber amplifier with a delivery fiber. The model allows independent inputs of many critical parameters, such as the delivery fiber length, temperature distribution, core size, Brillouin gain coefficient, as well as the gain fiber length. The SBS thresholds of the amplifiers under various conditions are computed. The results indicate that the delivery fiber lengths, core diameter, and Brillouin gain coefficient are the most influential parameters which make great impacts on amplifier performance. In addition, the gain fiber length also plays a role on SBS thresholds, but its impact is modest and normally less than a few percent. For an amplifier with a 25 microm gain fiber, to achieve more than 400 W output, the delivery fiber should have a Brillouin gain coefficient <1 x 10(-11) m/W with a length of less than 2 m and a core diameter of greater than 35 microm. (c) 2009 Optical Society of America

  15. Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy.

    PubMed

    Edginton, Ryan S; Mattana, Sara; Caponi, Silvia; Fioretto, Daniele; Green, Ellen; Winlove, C Peter; Palombo, Francesca

    2016-09-15

    Brillouin spectroscopy is an emerging technique in the biomedical field. It probes the mechanical properties of a sample through the interaction of visible light with thermally induced acoustic waves or phonons propagating at a speed of a few km/sec. Information on the elasticity and structure of the material is obtained in a nondestructive contactless manner, hence opening the way to in vivo applications and potential diagnosis of pathology. This work describes the application of Brillouin spectroscopy to the study of biomechanics in elastin and trypsin-digested type I collagen fibers of the extracellular matrix. Fibrous proteins of the extracellular matrix are the building blocks of biological tissues and investigating their mechanical and physical behavior is key to establishing structure-function relationships in normal tissues and the changes which occur in disease. The procedures of sample preparation followed by measurement of Brillouin spectra using a reflective substrate are presented together with details of the optical system and methods of spectral data analysis.

  16. Preparation of Extracellular Matrix Protein Fibers for Brillouin Spectroscopy

    PubMed Central

    Edginton, Ryan S.; Mattana, Sara; Caponi, Silvia; Fioretto, Daniele; Green, Ellen; Winlove, C. Peter; Palombo, Francesca

    2016-01-01

    Brillouin spectroscopy is an emerging technique in the biomedical field. It probes the mechanical properties of a sample through the interaction of visible light with thermally induced acoustic waves or phonons propagating at a speed of a few km/sec. Information on the elasticity and structure of the material is obtained in a nondestructive contactless manner, hence opening the way to in vivo applications and potential diagnosis of pathology. This work describes the application of Brillouin spectroscopy to the study of biomechanics in elastin and trypsin-digested type I collagen fibers of the extracellular matrix. Fibrous proteins of the extracellular matrix are the building blocks of biological tissues and investigating their mechanical and physical behavior is key to establishing structure-function relationships in normal tissues and the changes which occur in disease. The procedures of sample preparation followed by measurement of Brillouin spectra using a reflective substrate are presented together with details of the optical system and methods of spectral data analysis. PMID:27684584

  17. Detrimental Effect Elimination of Laser Frequency Instability in Brillouin Optical Time Domain Reflectometer by Using Self-Heterodyne Detection

    PubMed Central

    Li, Yongqian; Li, Xiaojuan; An, Qi; Zhang, Lixin

    2017-01-01

    A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra from fibers with different lengths measured by heterodyne detection, the maximum usable pulse width immune to laser frequency instability is obtained to be about 4 µs in a self-heterodyne detection Brillouin optical time domain reflectometer (BOTDR) system using a broad-band laser with low frequency stability. Applying the self-heterodyne detection of Rayleigh and Brillouin scattering in BOTDR system, we successfully demonstrate that the detrimental effect of laser frequency instability on Brillouin signals can be eliminated effectively. Employing the broad-band laser modulated by a 130-ns wide pulse driven electro-optic modulator, the observed maximum errors in temperatures measured by the local heterodyne and self-heterodyne detection BOTDR systems are 7.9 °C and 1.2 °C, respectively. PMID:28335508

  18. Detrimental Effect Elimination of Laser Frequency Instability in Brillouin Optical Time Domain Reflectometer by Using Self-Heterodyne Detection.

    PubMed

    Li, Yongqian; Li, Xiaojuan; An, Qi; Zhang, Lixin

    2017-03-20

    A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra from fibers with different lengths measured by heterodyne detection, the maximum usable pulse width immune to laser frequency instability is obtained to be about 4 µs in a self-heterodyne detection Brillouin optical time domain reflectometer (BOTDR) system using a broad-band laser with low frequency stability. Applying the self-heterodyne detection of Rayleigh and Brillouin scattering in BOTDR system, we successfully demonstrate that the detrimental effect of laser frequency instability on Brillouin signals can be eliminated effectively. Employing the broad-band laser modulated by a 130-ns wide pulse driven electro-optic modulator, the observed maximum errors in temperatures measured by the local heterodyne and self-heterodyne detection BOTDR systems are 7.9 °C and 1.2 °C, respectively.

  19. Spatial-division multiplexed hybrid Raman and Brillouin distributed sensor employing multicore fiber

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiyong; Dang, Yunli; Tang, Ming; Duan, Li; Wang, Meng; Fu, Songnian; Tong, Weijun; Liu, Deming

    2017-04-01

    Employing the multiple spatially independent channels offered by multicore fiber (MCF), spatial-division multiplexed (SDM) hybrid Raman and Brillouin distributed sensor has been demonstrated. The interrogation of Raman and Brillouin scattering are performed in distinct cores of the MCF, allowing for flexible management of the input powers between each of them, which is actually incompatible in hybrid Raman/Brillouin distributed system using single mode fibers (SMFs) due to the limitation of nonlinear effects. The proposed SDM system employs shared devices to generate pump pulse, but separate interrogation fiber channels. The combination of Raman and Brillouin sensing provides the capability of discriminative measurement between temperature and strain.

  20. Hybrid Raman/Brillouin-optical-time-domain-analysis-distributed optical fiber sensors based on cyclic pulse coding.

    PubMed

    Taki, M; Signorini, A; Oton, C J; Nannipieri, T; Di Pasquale, F

    2013-10-15

    We experimentally demonstrate the use of cyclic pulse coding for distributed strain and temperature measurements in hybrid Raman/Brillouin optical time-domain analysis (BOTDA) optical fiber sensors. The highly integrated proposed solution effectively addresses the strain/temperature cross-sensitivity issue affecting standard BOTDA sensors, allowing for simultaneous meter-scale strain and temperature measurements over 10 km of standard single mode fiber using a single narrowband laser source only.

  1. Slow light of subnanosecond pulses via stimulated Brillouin scattering in nonuniform fibers

    SciTech Connect

    Kalosha, V. P.; Chen, Liang; Bao, Xiaoyi

    2007-02-15

    We have proposed a way to obtain large optically controlled delay for subnanosecond pulses and simultaneously avoid the pulse distortions via stimulated Brillouin scattering (SBS) in optical fibers at cw pumping by the use of longitudinally nonuniform fibers with the Brillouin frequency linearly varying with distance. If the range of Brillouin frequency variation along the fiber covers the whole pulse spectrum, the delay of subnanosecond pulses is linearly proportional to the gain, could be larger than the pulse duration, and the pulse broadening is minimum. We have shown this by solving three-wave SBS equations for realistic fiber lengths, both single subnanosecond pulses and sequences of subnanosecond pulses.

  2. Nanosecond pulse pumped, narrow linewidth all-fiber Raman amplifier with stimulated Brillouin scattering suppression

    NASA Astrophysics Data System (ADS)

    Su, Rongtao; Zhou, Pu; Wang, Xiaolin; Lü, Haibin; Xu, Xiaojun

    2014-01-01

    We report on a narrow linewidth nanosecond all-fiber Raman amplifier core pumped by a pulsed laser at approximately 1030 nm. The Raman amplifier was based on a standard single-mode fiber with a length of ∼1 km, and stimulated Brillouin scattering (SBS) was suppressed by employing pulses with a short pulse width. 1083 nm pulses with an average power of 32.6 mW, a repetition rate of 2 MHz, and pulse widths of ∼7.2 ns were achieved. A maximum slope efficiency of 46.1% and a gain of 31 dB were obtained. The output Raman power can be scaled further by using fiber with shorter lengths and pump pulses with a higher power.

  3. Dependence of the brillouin frequency shift on strain and temperature in a photonic crystal fiber.

    PubMed

    Zou, Lufan; Bao, Xiaoyi; Afshar V, Shahraam; Chen, Liang

    2004-07-01

    The dependence of the Brillouin frequency shift on strain in a photonic crystal fiber (PCF) was measured at a wavelength of 1320 nm for the first time to the authors' knowledge. Together with measurements of the dependence of the Brillouin frequency shift on temperature in the PCF, we demonstrate the feasibility of the highly precise simultaneous measurement of temperature and strain by use of the PCF in a distributed Brillouin sensing system with a spatial resolution of 15 cm.

  4. Reduced Brillouin backscatter in CO2 laser-target interaction

    NASA Astrophysics Data System (ADS)

    Ng, A.; Offenberger, A. A.; Karttunen, S. J.

    1981-02-01

    A substantially reduced Brillouin reflection has been found for CO2 laser-irradiated high-density gas targets. In contrast to the high reflectivity (60%) previously observed for underdense hydrogen plasma, total backscatter (stimulated plus specular) is found to peak at 30% for incident intensity 5 times 10 to the twelfth W per square centimeter and decrease thereafter to 18% at 10 to the thirteenth W per square centimeter. The ponderomotive effects are postulated to account for these observations.

  5. Experimental observation of surface acoustic wave Brillouin scattering in a small-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Tchahame, Joël. Cabrel; Sylvestre, Thibaut; Phan Huy, Kien; Kudlinski, Alexandre; Laude, Vincent; Beugnot, Jean-Charles

    2016-04-01

    Light propagation in small-core photonic crystal fibers enables tight optical confinement over long propagation lengths to enhance light-matter interactions. Not only can photonic crystal fibers compress light spatially, they also provide a tunable means to control light-hypersound interactions. By exploring Brillouin light scattering in a small-core and high air-filling fraction microstructured fiber, we report the observation of Brillouin scattering from surface acoustic waves at lower frequencies than standard Brillouin scattering from bulk acoustic waves. This effect could find potential applications for optical sensing technologies that exploit surface acoustic waves.

  6. Demonstration of distributed shape sensing based on Brillouin scattering in multi-core fibers

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiyong; Soto, Marcelo A.; Tang, Ming; Thévenaz, Luc

    2017-04-01

    In this paper we demonstrate distributed shape sensing based on stimulated Brillouin scattering in a multi-core fiber (MCF). Brillouin optical time-domain analysis with differential pulse-width pairs is implemented to measure the local tangential strain-induced variation of the Brillouin frequency shift along different cores of the fiber. Employing the differential strain measured in multiple off-center cores in the MCF, distributed profiles of both bending angle and fiber curvature are parametrically retrieved. The paper presents the first demonstration of distributed bending sensing, providing the cornerstone to further develop the system into a fully distributed 3D shape sensor.

  7. Analysis of SNR penalty in Brillouin optical time-domain analysis sensors induced by laser source phase noise

    NASA Astrophysics Data System (ADS)

    Minardo, A.; Bernini, R.; Zeni, L.

    2016-02-01

    In this paper, we analyze numerically the effect of phase noise from the laser in Brillouin optical time-domain analysis (BOTDA) sensors. Due to laser phase noise, the phase shift between pump and probe beams is a stochastic variable with zero mean and variance changing with the position along the fiber. The numerical results, carried out for various fiber lengths and pump pulse durations, show that laser phase noise induces a reduction of the average Brillouin gain, as well as an increase of the overall system noise. Preliminary experimental results, carried out by use of a conventional BOTDA system and two DFB diode lasers having different linewidth (63 and 900 kHz), support the numerical analysis.

  8. Impact Wave Monitoring in Soil Using a Dynamic Fiber Sensor Based on Stimulated Brillouin Scattering

    PubMed Central

    Cui, Qingsong; Pamukcu, Sibel; Pervizpour, Mesut

    2015-01-01

    The impact wave response of soil due to a ball drop is monitored on a 30.5 cm by 30.5 cm square soil box using a fiber sensor with dynamic strain sensing capability. The experiments are conducted in real time using a simple one-laser one-modulator configuration with stimulated Brillouin scattering. The embedded BOTDA sensor grid successfully monitored the distribution and evolution of the inner strains of a sand bed during a mass impact on its surface. The measurement of the distributed dynamic strains was possible in several milliseconds and with 1 cm actual location resolution. This paper presents a time-domain signal analysis utilized for determining the dynamic strains in embedded fiber sensor. The results demonstrate the method to be a promising one for detection of subsurface vibration and movement in geotechnical Structure Health Monitoring (SHM). PMID:25856327

  9. Impact wave monitoring in soil using a dynamic fiber sensor based on stimulated brillouin scattering.

    PubMed

    Cui, Qingsong; Pamukcu, Sibel; Pervizpour, Mesut

    2015-04-08

    The impact wave response of soil due to a ball drop is monitored on a 30.5 cm by 30.5 cm square soil box using a fiber sensor with dynamic strain sensing capability. The experiments are conducted in real time using a simple one-laser one-modulator configuration with stimulated Brillouin scattering. The embedded BOTDA sensor grid successfully monitored the distribution and evolution of the inner strains of a sand bed during a mass impact on its surface. The measurement of the distributed dynamic strains was possible in several milliseconds and with 1 cm actual location resolution. This paper presents a time-domain signal analysis utilized for determining the dynamic strains in embedded fiber sensor. The results demonstrate the method to be a promising one for detection of subsurface vibration and movement in geotechnical Structure Health Monitoring (SHM).

  10. Distributed Brillouin optical fiber sensing for dynamic strain with frequency agility based on dual-modulation

    NASA Astrophysics Data System (ADS)

    Ba, Dexin; Zhou, Dengwang; Wang, Benzhang; Yin, Mingjing; Dong, Yongkang; Lu, Zhiwei; Fan, Zhigang

    2017-04-01

    A dynamic distributed Brillouin optical fiber sensing based on dual-modulation is proposed, in which the scanning of the Brillouin gain spectrum (BGS) is implemented by the combination of a single-frequency modulation and a frequency-agility modulation. The frequency of the single-frequency modulation is a little less than the Brillouin frequency shift of the fiber ( 10.8 GHz for silica fiber), while the tuning range of the frequency-agility modulation is required to cover only several-hundred MHz for the scanning of BGS, which can significantly reduce the bandwidth requirement for the arbitrary waveform generator and ultimately reduce the cost of dynamic Brillouin sensors. With a 30-m fiber, a 11.8-Hz strain is measured. The spatial resolution and the sampling rate are 1 m and 200 Hz, respectively.

  11. 40nm tunable multi-wavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Jia, Qingsong; Wang, Tianshu; Zhang, Peng; Dong, Keyan; Jiang, Huilin

    2014-12-01

    A Brillouin-Erbium multi-wavelength tunable fiber laser at C-band is demostrated. A 10 km long singlemode fiber(SMF), a 6 m long Erbium-doped fiber, two couplers, a wavelength division multiplexer, a isolator, an optical circulator, a 980nm pump laser and a narrow linewidth tunable laser are included in the structure. A segment of 10 km-long single-mode fiber (SMF) between the two ports of a 1×2 coupler is used as Brillouin gain. Ebiumdoped fiber amplifier (EDFA) consists of a segment of 6m er-doped fiber pumped by 980nm laser dioder . A narrow linewidth tunable laser from 1527 to 1607 nm as Brillouin bump, At the Brillouin pump power of 8mW and the 980 nm pump power of 400 mw, 16 output channels with 0.08 nm spacing and tuning range of 40 nm from 1527 nm to 1567 nm are achieved. We realize the tunable output of wavelength by adjusting the 980 nm pump power and the Brillouin pump wavelength. Stability of the multiwavelength fiber laser is also observed.

  12. System optimization of a long-range Brillouin-loss-based distributed fiber sensor.

    PubMed

    Dong, Yongkang; Chen, Liang; Bao, Xiaoyi

    2010-09-20

    We report a high-performance 25 km Brillouin-loss-based distributed fiber sensor through optimizing system parameters. First, the Brillouin spectrum distortion and measurement error induced by the excess amplification on probe pulse are investigated, and the results indicate that a low continuous-wave pump power is essential to decrease the measurement error. Then an optimal pulse pair is determined through the differential Brillouin gain evolution along the entire sensing fiber in a differential pulse-width pair Brillouin optical time domain analysis. Using dispersion-shifted fiber to allow a high-power probe pulse, we realize a 25 km sensing range with a spatial resolution of 30 cm and a strain accuracy of ±20 με, which we believe is the best performance in such a length, to the best of our knowledge.

  13. Experimental investigation on Brillouin scattering property in highly nonlinear photonic crystal fiber with hybrid core.

    PubMed

    Zou, Weiwen; He, Zuyuan; Hotate, Kazuo

    2012-05-07

    Brillouin scattering property in a highly nonlinear photonic crystal fiber (HNL-PCF) with hybrid-core structure is experimentally investigated. The HNL-PCF comprises a highly Ge-doped core surrounded by a triangularly-arranged F-doped buffer. It is experimentally shown that there exist five Brillouin resonance peaks with ~300 MHz frequency spacing in the Brillouin gain spectrum, which can be classified into two groups physcially attributed to two spatially separated layers of Ge-doped and F-doped regions. These peaks have similar linear dispersion characteristics and their effective acoustic velocities increase monotonically by the order of the peaks. The acousto-optic overlapping efficiency in the fiber is measured to be ~50%, which indicates that the stimulated Brillouin scattering threshold in the HNL-PCF is twofold enhanced. The temperature and strain dependences of the first resonance peak are also investigated, showing the similar behaviors as those in all-silica optical fibers.

  14. Stimulated Brillouin scattering in highly birefringent multimode tapered chalcogenide photonic crystal fiber for distributed optical sensors (Retraction Notice)

    NASA Astrophysics Data System (ADS)

    Baili, Amira; Cherif, Rim; Zghal, Mourad

    2016-09-01

    This paper, originally published on September 15, 2016, was retracted from the SPIE Digital Library on October 5, 2016, due to a high degree of similarity between specific portions of the text of the paper to the following publications: J. Tchahame, J. Beugnot, A. Kudlinski, and T. Sylvestre, "Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber," Opt. Lett. 40, 4281-4284 (2015). doi: 10.1364/OL.40.004281 W. W. Ke, X. J. Wang and X. Tang, "Stimulated Brillouin Scattering Model in Multi-Mode Fiber Lasers," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 20, no. 5, pp. 305-314, Sept.-Oct. 2014. doi: 10.1109/JSTQE.2014.2303256.

  15. Remote Water Temperature Measurements Based on Brillouin Scattering with a Frequency Doubled Pulsed Yb:doped Fiber Amplifier

    PubMed Central

    Schorstein, Kai; Popescu, Alexandru; Göbel, Marco; Walther, Thomas

    2008-01-01

    Temperature profiles of the ocean are of interest for weather forecasts, climate studies and oceanography in general. Currently, mostly in situ techniques such as fixed buoys or bathythermographs deliver oceanic temperature profiles. A LIDAR method based on Brillouin scattering is an attractive alternative for remote sensing of such water temperature profiles. It makes it possible to deliver cost-effective on-line data covering an extended region of the ocean. The temperature measurement is based on spontaneous Brillouin scattering in water. In this contribution, we present the first water temperature measurements using a Yb:doped pulsed fiber amplifier. The fiber amplifier is a custom designed device which can be operated in a vibrational environment while emitting narrow bandwidth laser pulses. The device shows promising performance and demonstrates the feasibility of this approach. Furthermore, the current status of the receiver is briefly discussed; it is based on an excited state Faraday anomalous dispersion optical filter. PMID:27873842

  16. Stimulated brillouin backscatter of a short-pulse laser

    SciTech Connect

    Hinkel, D.E.; Williams, E.A.; Berger, R.L.

    1994-11-03

    Stimulated Brillouin backscattering (SBBS) from a short-pulse laser, where the pulse length is short compared to the plasma length, is found to be qualitatively different than in the long pulse regime, where the pulse length is long compared to the plasma length. We find that after an initial transient of order the laser pulse length transit time, the instability reaches a steady state in the variables x{prime} = x {minus} V{sub g}t, t{prime} = t, where V{sub g} is the pulse group velocity. In contrast, SBBS in a long pulse can be absolutely unstable and grows indefinitely, or until nonlinearities intervene. We find that the motion of the laser pulse induces Doppler related effects that substantially modify the backscattered spectrum at higher intensities, where the instability is strongly coupled (i.e. , has a growth rate large compared to the ion acoustic frequency).

  17. Secure optical communication using stimulated Brillouin scattering in optical fiber

    NASA Astrophysics Data System (ADS)

    Yi, Lilin; Zhang, Tao; Li, Zhengxuan; Zhou, Junhe; Dong, Yi; Hu, Weisheng

    2013-03-01

    We propose to encrypt/decrypt high-speed optical signal using stimulated Brillouin scattering (SBS) effect in optical fiber for the first time. The broadened SBS gain or loss distorts the amplitude and phase of the optical signal so as to realize all-optical encryption. The corresponding SBS loss or gain with the same bandwidth and amplitude recovers the distorted signal to implement optical decryption. The encryption/decryption keys could be the SBS gain amplitude, bandwidth, central wavelength and the spectral shape, which are configurable and can be flexibly controlled by the users. The operation principle of the SBS based encryption and decryption is explained in detail. Complete encryption and error-free decryption for a 10.86-Gb/s on-off-keying signal has been experimentally demonstrated using broadband SBS amplification and absorption. The immunity of the proposed encryption method to the eavesdropper's attack is also analyzed. The SBS based secure optical communication is compatible with the current optical communication systems.

  18. Few-mode fiber based distributed curvature sensor through quasi-single-mode Brillouin frequency shift.

    PubMed

    Wu, Hao; Wang, Ruoxu; Liu, Deming; Fu, Songnian; Zhao, Can; Wei, Huifeng; Tong, Weijun; Shum, Perry Ping; Tang, Ming

    2016-04-01

    We proposed and demonstrated a few-mode fiber (FMF) based optical-fiber sensor for distributed curvature measurement through quasi-single-mode Brillouin frequency shift (BFS). By central-alignment splicing FMF and single-mode fiber (SMF) with a fusion taper, a SMF-components-compatible distributed curvature sensor based on FMF is realized using the conventional Brillouin optical time-domain analysis system. The distributed BFS change induced by bending in FMF has been theoretically and experimentally investigated. The precise BFS response to the curvature along the fiber link has been calibrated. A proof-of-concept experiment is implemented to validate its effectiveness in distributed curvature measurement.

  19. Stimulated Brillouin scattering in single-mode As(2)S(3) and As(2)Se(3) chalcogenide fibers.

    PubMed

    Florea, Catalin; Bashkansky, Mark; Dutton, Zachary; Sanghera, Jasbinder; Pureza, Paul; Aggarwal, Ishwar

    2006-12-11

    Stimulated Brillouin scattering was investigated for the first time in As(2)S(3) single-mode fibers, and also in As(2)Se(3). The propagation loss and numerical aperture of the fibers at 1.56 mum, along with the threshold intensity for the stimulated Brillouin scattering process were measured. From the threshold values we estimate the Brillouin gain coefficient and demonstrate record figure of merit for slow-light based applications in chalcogenide fibers.

  20. Research on distributed strain separation technology of fiber Brillouin sensing system combining an electric power optical fiber cable

    NASA Astrophysics Data System (ADS)

    Lei, Yuqing; Chen, Xi; Li, Jihui; Tong, Jie

    2013-12-01

    Brillouin-based optical fiber sensing system has been taken more and more attentions in power transmission line in recent years. However, there exists a temperature cross sensitivity problem in sensing system. Hence, researching on strain separation technology of fiber brillouin sensing system is an urgent requirement in its practical area. In this paper, a real-time online distributed strain separation calculation technology of fiber Brillouin sensing combining an electric power optical fiber cable is proposed. The technology is mainly composed of the Brillouin temperature-strain distributed measurement system and the Raman temperature distributed measurement system. In this technology, the electric power optical fiber cable is a special optical phase conductor (OPPC); the Brillouin sensing system uses the Brillouin optical time domain analysis (BOTDA) method. The optical unit of the OPPC includes single-mode and multimode fibers which can be used as sensing channel for Brillouin sensing system and Raman sensing system respectively. In the system networking aspect, the data processor of fiber Brillouin sensing system works as the host processor and the data processor of fiber Raman sensing system works as the auxiliary processor. And the auxiliary processor transfers the data to the host processor via the Ethernet interface. In the experiment, the BOTDA monitoring system and the Raman monitoring system work on the same optical unit of the OPPC simultaneously; In the data processing aspect, the auxiliary processor of Raman transfers the temperature data to the host processor of Brillouin via the Ethernet interface, and then the host processor of Brillouin uses the temperature data combining itself strain-temperature data to achieve the high sampling rate and high-precision strain separation via data decoupling calculation. The data decoupling calculation is achieved through the interpolation, filtering, feature point alignment, and the singular point prediction

  1. Residual strain sensor using Al-packaged optical fiber and Brillouin optical correlation domain analysis.

    PubMed

    Choi, Bo-Hun; Kwon, Il-Bum

    2015-03-09

    We propose a distributed residual strain sensor that uses an Al-packaged optical fiber for the first time. The residual strain which causes Brillouin frequency shifts in the optical fiber was measured using Brillouin optical correlation domain analysis with 2 cm spatial resolution. We quantified the Brillouin frequency shifts in the Al-packaged optical fiber by the tensile stress and compared them for a varying number of Al layers in the optical fiber. The Brillouin frequency shift of an optical fiber with one Al layer had a slope of 0.038 MHz/με with respect to tensile stress, which corresponds to 78% of that for an optical fiber without Al layers. After removal of the stress, 87% of the strain remained as residual strain. When different tensile stresses were randomly applied, the strain caused by the highest stress was the only one detected as residual strain. The residual strain was repeatedly measured for a time span of nine months for the purpose of reliability testing, and there was no change in the strain except for a 4% reduction, which is within the error tolerance of the experiment. A composite material plate equipped with our proposed Al-packaged optical fiber sensor was hammered for impact experiment and the residual strain in the plate was successfully detected. We suggest that the Al-packaged optical fiber can be adapted as a distributed strain sensor for smart structures, including aerospace structures.

  2. Aircraft laser sensing of sound velocity in water - Brillouin scattering

    NASA Technical Reports Server (NTRS)

    Hickman, G. D.; Harding, John M.; Carnes, Michael; Pressman, AL; Kattawar, George W.; Fry, Edward S.

    1991-01-01

    A real-time data source for sound speed in the upper 100 m has been proposed for exploratory development. This data source is planned to be generated via a ship- or aircraft-mounted optical pulsed laser using the spontaneous Brillouin scattering technique. The system should be capable (from a single 10 ns 500 mJ pulse) of yielding range resolved sound speed profiles in water to depths of 75-100 m to an accuracy of 1 m/s. The 100 m profiles will provide the capability of rapidly monitoring the upper-ocean vertical structure. They will also provide an extensive, subsurface-data source for existing real-time, operational ocean nowcast/forecast systems.

  3. Stimulated Brillouin Scattering in Multispecies Laser-Produced Plasmas

    SciTech Connect

    Young, P.E.; Foord, M.E.; Maximov, A.V.; Rozmus, W.

    1996-08-01

    Growth and saturation of the stimulated Brillouin scattering (SBS) instability has been studied in C, CH, and CH{sub 2} laser-produced plasmas which have nearly identical density profiles. The backscattered reflectivity is highest for the CH{sub 2} plasma ({approximately}15{percent}) and up to {approximately}5 times lower for the pure carbon plasma. This result is explained by the stationary inhomogeneous theory of SBS and confirmed by numerical simulations provided one allows for the nonuniform expansion of hydrogen and carbon ions that leads to an axial asymmetry of the SBS gain and results in the observation of a blueshifted scattered light spectrum from CH targets. {copyright} {ital 1996 The American Physical Society.}

  4. High spatial resolution distributed sensing in optical fibers by Brillouin gain-profile tracing.

    PubMed

    Sperber, Tom; Eyal, Avishay; Tur, Moshe; Thévenaz, Luc

    2010-04-12

    A novel BOTDA technique for distributed sensing of the Brillouin frequency in optical fibers with cm-order spatial resolution is proposed. The technique is based upon a simple modulation scheme, requiring only a single long pump pulse for acoustic excitation, and no subsequent interrogating pulse. Instead, the desired spatial mapping of the Brillouin response is extracted by taking the derivative of the probe signal. As a result, the spatial resolution is limited by the fall-time of the pump modulation, and the phenomena of secondary "echo" signals, typically appearing in BOTDA sensing methods based upon pre-excitation, is mitigated. Experimental demonstration of the detection of a Brillouin frequency variation significantly smaller than the natural Brillouin linewidth, with a 2cm spatial resolution, is presented.

  5. Techno-economic study of the value of high stimulated Brillouin scattering threshold single-mode fiber utilization in fiber-to-the-home access networks

    NASA Astrophysics Data System (ADS)

    Vaughn, Mark D.; Boh Ruffin, A.; Kobyakov, Andrey; Woodfin, Andrew; Mazzali, Claudio; Whitman, Robert; Boskovic, Aleksandra; Wagner, Richard E.; Kozischek, David; Meis, David

    2006-01-01

    Cost modeling reveals that deployment of fibers with a high stimulated Brillouin scattering threshold in fiber-to-the-home access networks can reduce material and labor expenditures by more than 20%. Theory and measurements of the high stimulated Brillouin scattering fiber are presented to demonstrate its employability.

  6. Perspectives on stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Garmire, Elsa

    2017-01-01

    This collection of papers describes research that goes into detail on some of the more important issues in the physics of stimulated Brillouin scattering. This perspective describes the earliest years of the physics of stimulated Brillouin scattering, along with key developments that have led to this technically and physically rich field of today’s nonlinear optics. Stimulated Brillouin has a profound effect in optical fiber communications, initially discovered by its limit on the transmitted power. By controlling SBS in fibers and making use of its phase conjugation properties in both fibers and bulk media, a wide range of applications have been enabled. Today ring Brillouin lasers in fibers, whispering gallery modes and in photonic integrated circuits provide optical delay lines and switches, pulse shapers and components for increasingly complex and important optical systems.

  7. Microresonator Brillouin laser stabilization using a microfabricated rubidium cell.

    PubMed

    Loh, William; Hummon, Matthew T; Leopardi, Holly F; Fortier, Tara M; Quinlan, Frank; Kitching, John; Papp, Scott B; Diddams, Scott A

    2016-06-27

    We frequency stabilize the output of a miniature stimulated Brillouin scattering (SBS) laser to rubidium atoms in a microfabricated cell to realize a laser system with frequency stability at the 10-11 level over seven decades in averaging time. In addition, our system has the advantages of robustness, low cost and the potential for integration that would lead to still further miniaturization. The SBS laser operating at 1560 nm exhibits a spectral linewidth of 820 Hz, but its frequency drifts over a few MHz on the 1 hour timescale. By locking the second harmonic of the SBS laser to the Rb reference, we reduce this drift by a factor of 103 to the level of a few kHz over the course of an hour. For our combined SBS and Rb laser system, we measure a frequency noise of 4 × 104 Hz2/Hz at 10 Hz offset frequency which rapidly rolls off to a level of 0.2 Hz2/Hz at 100 kHz offset. The corresponding Allan deviation is ≤2 × 10-11 for averaging times spanning 10-4 to 103 s. By optically dividing the signal of the laser down to microwave frequencies, we generate an RF signal at 2 GHz with phase noise at the level of -76 dBc/Hz and -140 dBc/Hz at offset frequencies of 10 Hz and 10 kHz, respectively.

  8. Interaction physics for the stimulated Brillouin scattering of a laser in laser driven fusion

    SciTech Connect

    Yadav, Pinki; Gupta, D.N.; Avinash, K.

    2014-07-01

    Energy exchange between pump wave and ion-acoustic wave during the stimulated Brillouin Scattering process in relativistic laser-plasma interactions is studied, including the effect of damping coefficient of electron-ion collision by obeying the energy and momentum conservations. The variations of plasma density and damping coefficient of electron-ion collision change the amplitudes of the interacting wave. The relativistic mass effect modifies the dispersion relations of the interacting waves and consequently, the energy exchange during the stimulated Brillouin Scattering is affected. The collisional damping of electron-ion collision in the plasma is shown to have an important effect on the evolution of the interacting waves. (author)

  9. Effect of collisions on amplification of laser beams by Brillouin scattering in plasmas

    SciTech Connect

    Humphrey, K. A.; Speirs, D. C.; Trines, R. M. G. M.; Norreys, P.; Fiuza, F.; Cairns, R. A.; Silva, L. O.

    2013-10-15

    We report on particle in cell simulations of energy transfer between a laser pump beam and a counter-propagating seed beam using the Brillouin scattering process in uniform plasma including collisions. The results presented show that the ion acoustic waves excited through naturally occurring Brillouin scattering of the pump field are preferentially damped without affecting the driven Brillouin scattering process resulting from the beating of the pump and seed fields together. We find that collisions, including the effects of Landau damping, allow for a more efficient transfer of energy between the laser beams, and a significant reduction in the amount of seed pre-pulse produced.

  10. Distributed Brillouin fiber optic strain monitoring applications in advanced composite materials

    NASA Astrophysics Data System (ADS)

    Bastianini, Filippo; Cargnelutti, Mario; Di Tommaso, Angelo; Toffanin, Massimo

    2003-08-01

    Composite materials based on glass, carbon and aramid fibers have many advantages such as fast application, lightweight and corrosion resistance, and are widely diffused for manufacturing of tanks, pipings and for restoration, upgrade and seismic retrofit of structures and historical heritage. As several questions regarding long term durability of composite strengthenings remains still unsolved, monitoring of strain and temperature is strongly recommended, respectively to assess proper load transfer and no glass phase transition of the polymeric matrix. In this research work strain and temperature distributed sensing trough Brillouin scattering in single-mode optical fibers was used in different tests in order to understand the influence of different fiber coatings and embedding techniques. Pressure tests were performed on a GFRP piping with inhomogeneous strengthening layout and Brillouin strain data were compared with conventional strain gages. A smart CFRP material has been also developed and evaluated in a seismic retrofit application on an historical building dated 1500 that was seriously damaged in the earthquake of 1997. The developed embedding technique has been demonstrated successful to obtain fiber-optic smart composites with low optical losses, and the data comparison between Brillouin and resistive strain gauges confirms Brillouin technique is very effective for composite monitoring.

  11. Fully-distributed fiber-optic high temperature sensing based on stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Hu, Di; Wang, Dorothy Y.; Wang, Anbo

    2013-06-01

    We proposed a Brillouin optical fiber time domain analysis (BOTDA)-based fully-distributed temperature system as high as 1000°C and spatial resolution to 5 meters. This technique is prominent for high spatial resolution fully distributed high temperature and stress sensing over long distance.

  12. Characterization of distributed modal birefringence in a few-mode fiber based on Brillouin dynamic grating.

    PubMed

    Li, An; Hu, Qian; Chen, Xi; Kim, Byoung Yoon; Shieh, William

    2014-06-01

    We propose and demonstrate generation of Brillouin dynamic grating (BDG) in a few-mode fiber (FMF) with a Gaussian pulse pump and a counterpropagating continuous wave pump in LP01 mode. Brillouin optical time-domain analysis (BOTDA) is achieved by launching a third Gaussian pulse probe in LP11 mode. With coherent detection and time-domain analysis on the backreflected probe signal, the modal birefringence of the FMF is characterized via the distributed BDG with high spatial resolution and high accuracy.

  13. Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

    PubMed

    Massey, Steven M; Spring, Justin B; Russell, Timothy H

    2008-07-21

    Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

  14. A theoretical study of transient stimulated Brillouin scattering in optical fibers seeded with phase-modulated light.

    PubMed

    Zeringue, Clint; Dajani, Iyad; Naderi, Shadi; Moore, Gerald T; Robin, Craig

    2012-09-10

    Beam combining of phase-modulated kilowatt fiber amplifiers has generated considerable interest recently. We describe in the time domain how stimulated Brillouin scattering (SBS) is generated in an optical fiber under phase-modulated laser conditions, and we analyze different phase modulation techniques. The temporal and spatial evolutions of the acoustic phonon, laser, and Stokes fields are determined by solving the coupled three-wave interaction system. Numerical accuracy is verified through agreement with the analytical solution for the un-modulated case and through the standard photon conservation relation for counter-propagating optical fields. As a test for a modulated laser, a sinusoidal phase modulation is examined for a broad range of modulation amplitudes and frequencies. We show that, at high modulation frequencies, our simulations agree with the analytical results obtained from decomposing the optical power into its frequency components. At low modulation frequencies, there is a significant departure due to the appreciable cross talk among the laser and Stokes sidebands. We also examine SBS suppression for a white noise source and show significant departures for short fibers from analytically derived formulas. Finally, SBS suppression through the application of pseudo-random bit sequence modulation is examined for various patterns. It is shown that for a fiber length of 9 m the patterns at or near n=7 provide the best mitigation of SBS with suppression factors approaching 17 dB at a modulation frequency of 5 GHz.

  15. Acousto-opto-mechanical theory for polarization maintaining optical fibers in Brillouin based sensing

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoling; Ansari, Farhad; Meng, Dewei; Bao, Tengfei

    2015-01-01

    Change in phase or wavelength for interferometric and fiber Bragg Gratings (FBG) based sensors can be described by strain-optic effects. In Brillouin sensors, strain sensitivity need to be expressed in terms of acousto-opto-mechanical properties of fibers. It is then possible to formulate theoretical relationships that lead to the evaluation of strain sensitivities and establishment of gauge factors for Brillouin based sensors. This article reports on the derivation of generalized relationships describing the strain sensitivity in terms of acousto-optic effects in optical fibers. In particular, the formulations correspond to polarization maintaining fibers at various polarization angles with respect to the slow axis of the fiber. The scope of research encompassed theoretical and experimental studies involving both single mode as well as polarization maintaining optical fibers subjected to strain under isothermal conditions. A high resolution BOTDA was employed in the experiments in order to verify the validity of theoretical relationships between strain and Brillouin frequency shifts for different polarization angles.

  16. A distributed fiber optic sensor system for dike monitoring using Brillouin optical frequency domain analysis

    NASA Astrophysics Data System (ADS)

    Nöther, Nils; Wosniok, Aleksander; Krebber, Katerina; Thiele, Elke

    2008-03-01

    We report on the development of a complete system for spatially resolved detection of critical soil displacement in river embankments. The system uses Brillouin frequency domain analysis (BOFDA) for distributed measurement of strain in silica optical fibers. Our development consists of the measurement unit, an adequate coating for the optical fibers and a technique to integrate the coated optical fibers into geotextiles as they are commonly used in dike construction. We present several laboratory and field tests that prove the capability of the system to detect areas of soil displacement as small as 2 meters. These are the first tests of truly distributed strain measurements on optical fibers embedded into geosynthetics.

  17. Observation of stimulated Brillouin scattering in polymer optical fiber with pump-probe technique.

    PubMed

    Mizuno, Yosuke; Kishi, Masato; Hotate, Kazuo; Ishigure, Takaaki; Nakamura, Kentaro

    2011-06-15

    Stimulated Brillouin scattering (SBS) in a perfluorinated graded-index polymer optical fiber (POF) with 120 μm core diameter was experimentally observed for the first time, to the best of our knowledge, at 1.55 μm wavelength with the pump-probe technique. Compared to spontaneous Brillouin scattering previously reported, the Brillouin gain spectrum (BGS) was detected with an extremely high signal-to-noise ratio, even with a short POF (1 m) and scrambled polarization state. We also investigated the BGS dependences on probe power and temperature, which indicate that SBS in a POF measured with this technique can be utilized to develop high-accuracy temperature sensing systems.

  18. Continuous wave stimulated Brillouin scattering phase conjugation and beam cleanup in optical fiber

    NASA Astrophysics Data System (ADS)

    Massey, Steven M.; Spring, Justin B.; Russell, Timothy H.

    2009-02-01

    A review of research into stimulated Brillouin scattering (SBS) phase conjugation and beam cleanup conducted at the Air Force Institute of Technology is presented. CW phase conjugation was demonstrated using SBS in short lengths of multi-mode, step-index fiber. A fidelity of 0.8 was achieved using a 0.06-NA fiber of 40 m length and a 0.13-NA fiber at 15 m length. In modeling and experiment, the fidelity declined as fiber length or numerical aperture increased. A relationship was established empirically between step-index fiber parameters and the phase conjugation fidelity. In addition, increased fidelity was related to an increase in the effective Brillouin gain coefficient in step-index fibers. Beam cleanup was observed in both graded-index and step-index fibers. The Stokes beam generated in long, multimode, graded-index fibers was analyzed using spatial and phase methods and found to be a low-order mode of the fiber instead of a phase conjugate of the pump. SBS in long, graded-index fibers was used to combine multiple beams and to improve the beam quality of a single aberrated beam.

  19. Brillouin characterisation of optical microfibers

    NASA Astrophysics Data System (ADS)

    Farhan, Kazi Tasneem

    The sleek shape of microfiber helps it to confine the light tightly and generate high nonlinear effect, which is 1000 times higher than the standard fiber. This project focuses on fabricating microfiber samples with different taper lengths and different waist diameter from three different kinds of fiber, single mode fiber (SMF), Gedoped and Ga-doped. All the samples were characterised in terms of Brillouin scattering and Brillouin gain and Brillouin lasing, and compared to each other and to the SMF fiber. Stimulated Brillouin scattering (SBS) has been demonstrated for short microfibers of length less than 10cm. The nonlinear effects of long tapers have not been reported yet. The theoretical perspective related to microfibers indicate the possibility of generation of stronger signals and newer frequencies. Among the many nonlinear effects Brillouin scattering is the easiest to observe and has not been studied using long microfibers until now. In this project microfibers of different lengths and waist diameter are fabricated. The microfibers were made from three different kinds of fiber: SMF, Germanium doped (Ge-doped) and Gallium doped (Ga-doped). The shapes of the fabricated samples are profiled to match the shape with the numerically simulated shape. The power performances are studied so that samples with minimum losses are used for Brillouin characterisation. The first experiment uses the microfiber samples for testing and recording the changes in Stokes generation for the different dimensions of each sample in a Brillouin scattering setup. These microfibers are tested in s second experiment of Brillouin laser setup to explore their possibilities of lasing. In the third experiment the microfibers are used in a pump probe technique setup to spatially measure the Brillouin gain along the length of each sample.

  20. Raman fiber lasers

    NASA Astrophysics Data System (ADS)

    Supradeepa, V. R.; Feng, Yan; Nicholson, Jeffrey W.

    2017-02-01

    High-power fiber lasers have seen tremendous development in the last decade, with output powers exceeding multiple kilowatts from a single fiber. Ytterbium has been at the forefront as the primary rare-earth-doped gain medium owing to its inherent material advantages. However, for this reason, the lasers are largely confined to the narrow emission wavelength region of ytterbium. Power scaling at other wavelength regions has lagged significantly, and a large number of applications rely upon the diversity of emission wavelengths. Currently, Raman fiber lasers are the only known wavelength agile, scalable, high-power fiber laser technology that can span the wavelength spectrum. In this review, we address the technology of Raman fiber lasers, specifically focused on the most recent developments. We will also discuss several applications of Raman fiber lasers in laser pumping, frequency conversion, optical communications and biology.

  1. Stimulated Brillouin scattering effects and suppression techniques in high power fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Zmuda, Michael Wayne

    This dissertation develops a model for numerical analysis of stimulated Brillouin scattering (SBS) effects and the development of suppression techniques for the realization of increased output power levels for high power ytterbium-doped dual clad fiber amplifiers. The overall objective of this effort is to develop and validate a predictive model to assist in the determination of the most effective techniques for increasing SBS thresholds within ytterbium-doped fiber amplifiers in order to realize increased power output. The goal is to demonstrate an increase in SBS threshold that would increase the output power potential in ytterbium-doped fiber amplifiers by at least an order of magnitude. The approach determines the effect of changing the acoustic properties of fiber cores on the Brillouin frequencies and the effects of various signal modulation schemes on active ytterbium-doped fiber amplifiers. In addition, temperature effects and temperature differentials within the fibers are predicted and measured, both with passive and active fibers. Brillouin center frequency responses of various germanium dopant concentrations within the cores, as well as the effects of fiber segment combinations are measured in the lab. The effects of various phase modulation schemes of the signal are predicted and measured for passive fibers. Results from these measurements are used to validate and adjust the model accordingly. Finally, the manufacturability of relevant characteristics required to achieve such SBS suppression is evaluated, identifying constraints and limitations for utilization of low cost fabrication techniques. The final model, validated and adjusted with empirical results, supports the suppression of SBS in standard ytterbium-doped fiber amplifiers by over a decade.

  2. Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

    PubMed

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  3. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    PubMed Central

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring. PMID:22346672

  4. 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.

  5. A photonic approach for microwave/millimeter-wave frequency measurement using stimulated brillouin scattering in single mode fiber

    NASA Astrophysics Data System (ADS)

    Xu, K.; Sun, X. Q.; Fu, S. N.; Wu, J.; Hong, X. B.; Shum, Perry; Lin, J. T.

    2010-04-01

    A photonic approach for microwave/millimeter-wave (MMW) frequency measurement is proposed and demonstrated based on stimulated Brillouin scattering (SBS) of a 20-km standard single mode fiber (SSMF). After the MMW signal is modulated to a laser source with two sidebands using optical carrier suppression (OCS) modulation, its frequency can be easily measured by monitoring the SBS-induced amplification with a power meter. Due to the 1-pm resolution of a tunable pump laser source, a frequency measurement range of 1-40 GHz is demonstrated in our experiment with a frequency resolution of 125 MHz. We believe the frequency measurement range can be further extended to satisfy photonic radar front-end processing application.

  6. 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.

  7. Brillouin distributed sensor over a 200km fiber-loop using a dual-pump configuration and colour coding

    NASA Astrophysics Data System (ADS)

    Le Floch, S.; Sauser, F.; Llera, M.; Rochat, E.

    2014-05-01

    In this paper, we propose a new Brillouin Optical Time Domain Analysis (BOTDA) set-up that combines simultaneous Brillouin gain/loss measurements with colour coding. This technique gives the advantage that the pump power can greatly be increased, compared to other coding schemes, thus increasing the sensing range. A measurement over a 200 km fiber-loop is performed, with a 3 meter spatial resolution and an accuracy of +/- 3 MHz (2σ) at the end of the sensing fiber. To the best of our knowledge, this is the best result obtained with a Brillouin sensor without Raman amplification.

  8. Stimulated Brillouin scattering of laser in semiconductor plasma embedded with nano-sized grains

    NASA Astrophysics Data System (ADS)

    Sharma, Giriraj; Dad, R. C.; Ghosh, S.

    2015-07-01

    A high power laser propagating through semiconductor plasma undergoes Stimulated Brillouin scattering (SBS) from the electrostrictively generated acoustic perturbations. We have considered that nano-sized grains (NSGs) ions are embedded in semiconductor plasma by means of ion implantation. The NSGs are bombarded by the surrounding plasma particles and collect electrons. By considering a negative charge on the NSGs, we present an analytically study on the effects of NSGs on threshold field for the onset of SBS and Brillouin gain of generated Brillouin scattered mode. It is found that as the charge on the NSGs builds up, the Brillouin gain is significantly raised and the threshold pump field for the onset of SBS process is lowered.

  9. Stimulated Brillouin scattering of laser in semiconductor plasma embedded with nano-sized grains

    SciTech Connect

    Sharma, Giriraj; Dad, R. C.; Ghosh, S.

    2015-07-31

    A high power laser propagating through semiconductor plasma undergoes Stimulated Brillouin scattering (SBS) from the electrostrictively generated acoustic perturbations. We have considered that nano-sized grains (NSGs) ions are embedded in semiconductor plasma by means of ion implantation. The NSGs are bombarded by the surrounding plasma particles and collect electrons. By considering a negative charge on the NSGs, we present an analytically study on the effects of NSGs on threshold field for the onset of SBS and Brillouin gain of generated Brillouin scattered mode. It is found that as the charge on the NSGs builds up, the Brillouin gain is significantly raised and the threshold pump field for the onset of SBS process is lowered.

  10. Dimensionality reduction and dynamical filtering: Stimulated Brillouin scattering in optical fibers.

    PubMed

    Setra, Rafael G; Arroyo-Almanza, Diana A; Ni, Zetian; Murphy, Thomas E; Roy, Rajarshi

    2015-08-01

    Stimulated Brillouin scattering (SBS) is a noise-driven nonlinear interaction between acoustical and optical waves. In optical fibers, SBS can be observed at relatively low optical powers and can severely limit signal transmission. Although SBS is initiated by high dimensional noise, it also exhibits many of the hallmarks of a complex nonlinear dynamical system. We report here a comprehensive experimental and numerical study of the fluctuations in the reflected Stokes wave produced by SBS in optical fibers. Using time series analysis, we demonstrate a reduction of dimensionality and dynamical filtering of the Stokes wave. We begin with a careful comparison of the measured average transmitted and reflected intensities from below the SBS threshold to saturation of the transmitted power. Initially the power spectra and correlation functions of the time series of the reflected wave fluctuations at the SBS threshold and above are measured and simulated. Much greater dynamical insight is provided when we study the scaling behavior of the intensity fluctuations using Hurst exponents and detrended fluctuation analysis for time scales extending over six orders of magnitude. At the highest input powers, we notice the emergence of three distinct dynamical scaling regimes: persistent, Brownian, and antipersistent. Next, we explore the Hilbert phase fluctuations of the intensity time series and amplitude-phase coupling. Finally, time-delay embedding techniques reveal a gradual reduction in dimensionality of the spatiotemporal dynamics as the laser input is increased toward saturation of the transmitted power. Through all of these techniques, we find a transition from noisier to smoother dynamics with increasing input power. We find excellent agreement between our experimental measurements and simulations.

  11. Investigation of laser induced parametric interactions in optical waveguides and fibers

    NASA Technical Reports Server (NTRS)

    Yu, C.

    1978-01-01

    Experimental and theoretical aspects of the laser pump depletion characteristics in an optical fiber due to stimulated Raman scattering, and stimulated Brillouin scattering were studied. A review is presented of research in fiber transmission accompanied by stimulated scattering. Results of experimental work with tunable dye lasers and argon lasers are presented. The spectral profiles of the laser pump and its transmitted light through the fiber are given.

  12. Distributed Temperature and Strain Discrimination with Stimulated Brillouin Scattering and Rayleigh Backscatter in an Optical Fiber

    PubMed Central

    Zhou, Da-Peng; Li, Wenhai; Chen, Liang; Bao, Xiaoyi

    2013-01-01

    A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF) with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA) with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR). These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved. PMID:23385406

  13. Distributed temperature and strain discrimination with stimulated brillouin scattering and rayleigh backscatter in an optical fiber.

    PubMed

    Zhou, Da-Peng; Li, Wenhai; Chen, Liang; Bao, Xiaoyi

    2013-01-31

    A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF) with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA) with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR). These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved.

  14. Brillouin optical spectrum analyzer monitoring of subcarrier-multiplexed fiber-optic signals.

    PubMed

    Stern, Yonatan; Zhong, Kun; Schneider, Thomas; Ben-Ezra, Yossef; Zhang, Ru; Tur, Moshe; Zadok, Avi

    2013-09-01

    Optical spectral analysis of closely spaced, subcarrier multiplexed fiber-optic transmission is performed, based on stimulated Brillouin scattering (SBS). The Brillouin gain window of a single, continuous-wave pump is scanned across the spectral extent of the signal under test. The polarization pulling effect associated with SBS is employed to improve the rejection ratio of the analysis by an order of magnitude. Ten tones, spaced by only 10 MHz and each carrying random-sequence on-off keying data, are clearly resolved. The measurement identifies the absence of a single subcarrier, directly in the optical domain. The results are applicable to the monitoring of optical orthogonal frequency domain multiplexing and radio over fiber transmission.

  15. Differential Brillouin fiber sensor based on phase difference on double-sideband pump wave

    NASA Astrophysics Data System (ADS)

    Lin, Wenqiao; Hong, Xiaobin; Yang, Zhisheng; Wu, Jian; Lin, Jintong

    2015-06-01

    A configuration based on phase difference on a double-sideband pump wave is proposed to detect the differential variation of temperature or strain in single-mode optical fibers. In our configuration, a probe wave only experiences a differential Brillouin gain contributed by the perturbation of temperature or strain in the sensing fiber. As a result, the power limitation of the probe wave can be alleviated and the photodetector in our configuration does not easily become saturated in the case of a longer sensing range. The spatial resolution is determined by the duration of the phase difference on the two sidebands and the signal-to-noise of our system is nearly twice as high as that of a differential pulse-width pair Brillouin optical time domain analysis sensor since a π-phase shift on the pump wave is employed. The properties and performances of our method are also theoretically derived and experimentally validated.

  16. Power-penalty-free all-optical decryption using stimulated Brillouin scattering in optical fiber

    NASA Astrophysics Data System (ADS)

    Yi, L. L.; Zhang, T.; Li, Z. X.; Zhang, Y.; Dong, Y.; Hu, W. S.

    2013-04-01

    We propose to all-optically encrypt and decrypt high-speed optical signals using the stimulated Brillouin scattering (SBS) effect in optical fiber for the first time. The spectral-shaped SBS gain or loss distorts the broadband optical signal so as to realize optical encryption. A corresponding SBS loss or gain with the same spectral shape and amplitude recovers the distorted signal to implement optical decryption. We experimentally demonstrate the SBS encryption/decryption process on 10.86 Gb s-1 non-return-to-zero-on-off-keying (NRZ-OOK) data using phase-modulated Brillouin pumps to generate a spectral-shaped SBS gain/loss encryption key, and no power penalty is observed for the best decryption case. The proposed all-optical encryption/decryption method is completely compatible with existing fiber-optic communication systems.

  17. Pulse temporal compression by two-stage stimulated Brillouin scattering and laser-induced breakdown

    NASA Astrophysics Data System (ADS)

    Liu, Zhaohong; Wang, Yulei; Wang, Hongli; Bai, Zhenxu; Li, Sensen; Zhang, Hengkang; Wang, Yirui; He, Weiming; Lin, Dianyang; Lu, Zhiwei

    2017-06-01

    A laser pulse temporal compression technique combining stimulated Brillouin scattering (SBS) and laser-induced breakdown (LIB) is proposed in which the leading edge of the laser pulse is compressed using SBS, and the low intensity trailing edge of the laser pulse is truncated by LIB. The feasibility of the proposed scheme is demonstrated by experiments in which a pulse duration of 8 ns is compressed to 170 ps. Higher compression ratios and higher efficiency are expected under optimal experimental conditions.

  18. Long-range distributed Brillouin fiber sensors by use of an unbalanced double sideband probe.

    PubMed

    Bernini, Romeo; Minardo, Aldo; Zeni, Luigi

    2011-11-21

    We propose and demonstrate a long-range Brillouin Optical Time-Domain Analysis (BOTDA) distributed sensing system making use of an unbalanced double sideband probe formed by a Stokes and an anti-Stokes line. In particular, we show that for each measuring condition an optimal Stokes /anti-Stokes input power ratio exists, allowing a larger suppression of nonlocal effects induced by pump depletion. Experiments on a 50 km single-mode sensing fiber with 5 meters spatial resolution are reported.

  19. Broadly tunable multiwavelength fiber laser with bismuth-oxide EDF using large effective area fiber

    NASA Astrophysics Data System (ADS)

    Ramzia Salem, A. M.; Al-Mansoori, M. H.; Hizam, H.; Mohd Noor, S. B.; Mahdi, M. A.

    2011-02-01

    A multiwavelength laser comb using 2.49 m Bismuth-oxide erbium-doped fiber (Bi-EDF) with different lengths of large effective area fiber (LEAF) in a ring cavity configuration is realized. The Bi-EDF is used as the linear gain medium and LEAF is used as the non-linear gain medium for stimulated Brillouin scattering. Out of the four different lengths, the longest length of 25 km LEAF exhibits the widest tuning range of 44 nm (1576 to 1620 nm) in the L-band at 264 mW pump power and 5 mW Brillouin pump power. In addition, a total of 15 output channels are achieved with total average output power of -8 dBm from this laser structure. All Brillouin Stokes signals exhibit high peak power of above -20 dBm per signal and their optical signal-to-noise ratio of greater than 15 dB.

  20. Characterization of phase-shifted Brillouin dynamic gratings in a polarization maintaining fiber

    NASA Astrophysics Data System (ADS)

    Zhou, Dengwang; Dong, Yongkang; Xu, Pengbai; Teng, Lei; Zhang, Hongying; Lu, Zhiwei

    2016-11-01

    We numerically calculate and experimentally investigate the characterization of phase-shifted Brillouin dynamic gratings (PS-BDGs) in a polarization maintaining fiber (PMF). A phase-shifted point is induced into the middle of a conventional BDG through phase-modulating one of the two pump pulse, generating a PS-BDG thanks to the stimulated Brillouin scattering (SBS). When the frequency difference between a high frequency pump1 pulse with 1ns and π-1ns and a low frequency pump2 pulse with 100ps is equal to the Brillouin frequency shift of the PMF, a transient PS-BDG with a 3dBbandwidth of 354MHz of the notch spectrum is simulated based on the coupled-wave equations of BDG. By increasing the repetition rate up to 250MHz, an enhanced PS-BDG with a deep notch depth is obtained since the residual acoustic wave of the former SBS process is enhanced by the optical waves of the latter SBS process. Then a proof-of-concept experiment is built to verify the transient PS-BDG and the results show that the notch feature is consistent with the simulation results and the notch frequency of the PS-BDG can be changed by tuning the phase shift Δϕ . The proposed PS-BDGs have important potential applications in optical fiber sensing, microwave photonics, all-optical signal processing and RoF (radio-over-fiber) networks.

  1. High-sensitivity temperature sensing using higher-order Stokes stimulated Brillouin scattering in optical fiber.

    PubMed

    Iezzi, Victor Lambin; Loranger, Sébastien; Marois, Mikaël; Kashyap, Raman

    2014-02-15

    In an effort to reduce the cost of sensing systems and make them more compact and flexible, Brillouin scattering has been demonstrated as a useful tool, especially for distributed temperature and strain sensing (DTSS), with a resolution of a few centimeters over several tens of kilometers of fiber. However, sensing is limited by the Brillouin frequency shift's sensitivity to these parameters, which are of the order of ~1.3  MHz/°C and of ~0.05  MHz/με for standard fiber. In this Letter, we demonstrate a new and simple technique for enhancing the sensitivity of sensing by using higher-orders Stokes shifts with stimulated Brillouin scattering (SBS). By this method, we multiply the sensitivity of the sensor by the number of the Stokes order used, enhanced by six-fold, therefore reaching a sensitivity of ~7  MHz/°C, and potentially ~0.30  MHz/με. To do this, we place the test fiber within a cavity to produce a frequency comb. Based on a reference multiorder SBS source for heterodyning, this system should provide a new distributed sensing technology with significantly better resolution at a potentially lower cost than currently available DTSS systems.

  2. Brillouin scattering in multi-core optical fibers for sensing applications

    PubMed Central

    Mizuno, Yosuke; Hayashi, Neisei; Tanaka, Hiroki; Wada, Yuji; Nakamura, Kentaro

    2015-01-01

    We measure the Brillouin gain spectra in two cores (the central core and one of the outer cores) of a ~3-m-long, silica-based, 7-core multi-core fiber (MCF) with incident light of 1.55 μm wavelength, and investigate the Brillouin frequency shift (BFS) and its dependence on strain and temperature. The BFSs of both the cores are ~10.92 GHz, and the strain- and temperature-dependence coefficients of the BFS in the central core are 484.8 MHz/% and 1.08 MHz/°C, respectively, whereas those in the outer core are 516.9 MHz/% and 1.03 MHz/°C. All of these values are not largely different from those in a silica single-mode fiber, which is expected because the cores are basically composed of the same material (silica). We then analyze the difference in structural deformation between the two cores when strain is applied to the fiber, and show that it does not explain the difference in the BFS dependence of strain in this case. The future prospect on distributed strain and temperature sensing based on Brillouin scattering in MCFs is finally presented. PMID:26065718

  3. Dependence of Brillouin frequency shift on water absorption ratio in polymer optical fibers

    NASA Astrophysics Data System (ADS)

    Minakawa, Kazunari; Koike, Kotaro; Hayashi, Neisei; Koike, Yasuhiro; Mizuno, Yosuke; Nakamura, Kentaro

    2016-06-01

    We studied the dependence of the Brillouin frequency shift (BFS) on the water-absorption ratio in poly(methyl methacrylate)-based polymer optical fibers (POFs) to clarify the effect of the humidity on POF-based Brillouin sensors. The BFS, deduced indirectly using an ultrasonic pulse-echo technique, decreased monotonically as the water absorption ratio increased, mainly because of the decrease in the Young's modulus. For the same water absorption ratio, the BFS change was larger at a higher temperature. The maximal BFS changes (absolute values) at 40, 60, and 80 °C were 158, 285, and 510 MHz, respectively (corresponding to the temperature changes of ˜9 °C, ˜16 °C, and ˜30 °C). Thus, some countermeasure against the humidity is indispensable in implementing strain/temperature sensors based on Brillouin scattering in POFs, especially at a higher temperature. On the other hand, Brillouin-based distributed humidity sensors might be developed by exploiting the BFS dependence on water absorption in POFs.

  4. Long integral temperature Brillouin sensor for off- shore wind energy power supply lines

    NASA Astrophysics Data System (ADS)

    Quintela, M. A.; Ullán, A.; Quintela, A.; Galindez, C.; Perez-Herrera, R. A.; López-Amo, M.; Lopez-Higuera, J. M.

    2011-05-01

    A hybrid Erbium-Brillouin fiber laser sensor to measure the temperature along 22 km fiber is proposed and experimentally demonstrated. A multi-line laser oscillation is induced by the Brillouin gain of different concatenated transducer fiber sections placed in the ring cavity. Integral temperature measurements of each fiber section are obtained through each laser line. This sensor can be used to monitor the temperature of off-shore wind energy power cables.

  5. Equidistance difference optimum method to enhance measuring space of Brillouin optical fiber sensor

    NASA Astrophysics Data System (ADS)

    He, Jianping; Zhou, Zhi; Ou, Jinping

    2013-09-01

    Brillouin optic time-domain analysis/reflectometry (BOTDA/R) is a fully distributed optical sensing technique that can provide strain or temperature information along the whole length of a single-mode fiber and has attracted worldwide attentions in recent years. However, both spatial and distance resolution of BOTDA/R are too low to satisfy the measurement of local damage, and enhancing the performance of spatial or distance resolution is considered to be a problem. A novel equidistance difference optimum method is proposed to compensate for the weak spatial and distance resolution of BOTDA/R. The principle of the proposed method is introduced, and two demonstration tests are carried out to validate the local damage detection ability. The experimental results show that the Brillouin optical fiber sensor measuring space can cover any part of the sensor without changing the default values of the Brillouin system, which can greatly enrich the information of measured elements and detect the local damages well.

  6. Small-scale self-focusing of 200 ps laser pulses in Brillouin amplification

    NASA Astrophysics Data System (ADS)

    Yuan, Hang; Wang, Yu-Lei; Lü, Zhi-Wei; Zheng, Zhen-Xing

    2015-09-01

    Brillouin amplification is a new method to obtain high power hundred-picosecond laser pulses for shock ignition. The laser pulse’s intensity can be amplified to 10 GW/cm2 through this method. In order to determine the near-field quality, the relationship between the Brillouin amplification gain and the B integral in the stimulated Brillouin scattering (SBS) energy transfer process was studied, and numerical simulations and calculations were carried out to explain the process. For achieving an output intensity of 10 GW/cm2 under the condition that the effect of small-scale self-focusing is insignificant in the Brillouin amplification, the influence of the configuration parameters on the Brillouin amplification and the B integral was investigated. The results showed that the 10 GW/cm2 high power output can be obtained by optimizing the intensities of the pump and Stokes light and choosing an appropriate SBS medium. Project supported by the National Natural Science Foundation of China (Grant Nos. 61378007 and 61138005) and the Fundamental Research Funds for the Central Universities, China (Grant No. HIT. IBRSEM. A. 201409).

  7. High speed data encryption and decryption using stimulated Brillouin scattering effect in optical fiber

    NASA Astrophysics Data System (ADS)

    Yi, Lilin; Zhang, Tao; Hu, Weisheng

    2011-11-01

    A novel all-optical encryption/decryption method based on stimulated Brillouin scattering (SBS) effect in optical fiber is proposed for the first time. The operation principle is explained in detail and the encryption and decryption performance is experimentally evaluated. The encryption keys could be the SBS gain amplitude, bandwidth, central wavelength and spectral shape, which are configurable and flexibly controlled by the users. We experimentally demonstrate the SBS encryption/decryption process of a 10.86-Gb/s non-return-to-zero (NRZ) data by using both phase-modulated and current-dithered Brillouin pumps for proof-of-concept. Unlike the traditional optical encryption methods of chaotic communications and optical code-division-multiplexing access (OCDMA), the SBS based encryption/decryption technique can directly upgrade the current optical communication system to a secure communication system without changing the terminal transceivers, which is completely compatible with the current optical communication systems.

  8. Brillouin gain spectrum dependence on large strain in perfluorinated graded-index polymer optical fiber.

    PubMed

    Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2012-09-10

    We investigate the dependence of Brillouin gain spectra on large strain of > 20% in a perfluorinated graded-index polymer optical fiber, and prove, for the first time, that the dependence of Brillouin frequency shift (BFS) is highly non-monotonic. We predict that temperature sensors even with zero strain sensitivity can be implemented by use of this non-monotonic nature. Meanwhile, the Stokes power decreases rapidly when the applied strain is > ~10%. This behavior seems to originate from the propagation loss dependence on large strain. By exploiting the Stokes power dependence, we can probably solve the problem of how to identify the applied strain, when the identification is difficult only by BFS because of its non-monotonic nature.

  9. Optical low coherence reflectometry for measuring a stationary Brillouin grating induced under uniform pumping in a short optical fiber

    NASA Astrophysics Data System (ADS)

    Takada, Kazumasa; Yasuno, Takahiro

    2017-01-01

    We demonstrate that valuable information on the distributed Brillouin spectra of an optical waveguide can be derived from a stationary Brillouin grating measurement under uniform pumping with optical low coherence reflectometry. We up-convert the frequencies of the probe and pump light waves by the Brillouin frequency and detect the Stokes light in the same way that we detect the Fresnel and Rayleigh backreflections in the fiber. The pump light wave that propagates toward the optical balanced mixer is blocked by using a polarization diversity technique and the distributed Brillouin gratings excited in an 82-cm long non-birefringent single mode fiber are measured at a spatial resolution of the order of 1 mm.

  10. Strain event detection using a double-pulse technique of a Brillouin scattering-based distributed optical fiber sensor.

    PubMed

    Cho, Seok-Beom; Lee, Jung-Ju; Kwon, Il-Bum

    2004-09-06

    Stimulated Brillouin scattering in optical fibers can be used to measure strain or temperature in a distributed manner. Brillouin optical time domain analysis (BOTDA) is the most common sensor system based on the Brillouin scattering. To improve the spatial resolution of these measurements, shorter pulses must be used, resulting in reduced signal powers causing a decrease of the dynamic range. In this paper, a doublepulse technique was proposed to enhance the spatial resolution of BOTDA. Experimental results showed that the ability to resolve two adjacent events could be enhanced, about twice, by using a double-pulsed pump light without decreases in the dynamic range.

  11. Depolarized guided acoustic wave Brillouin scattering in hollow-core photonic crystal fibers.

    PubMed

    Zhong, Wenjia Elser née; Stiller, Birgit; Elser, Dominique; Heim, Bettina; Marquardt, Christoph; Leuchs, Gerd

    2015-10-19

    By performing quantum-noise-limited optical heterodyne detection, we observe polarization noise in light after propagation through a hollow-core photonic crystal fiber (PCF). We compare the noise spectrum to the one of a standard fiber and find an increase of noise even though the light is mainly transmitted in air in a hollow-core PCF. Combined with our simulation of the acoustic vibrational modes in the hollow-core PCF, we are offering an explanation for the polarization noise with a variation of guided acoustic wave Brillouin scattering (GAWBS). Here, instead of modulating the strain in the fiber core as in a solid core fiber, the acoustic vibrations in hollow-core PCF influence the effective refractive index by modulating the geometry of the photonic crystal structure. This induces polarization noise in the light guided by the photonic crystal structure.

  12. KrF laser amplifier with phase-conjugate Brillouin retroreflectors.

    PubMed

    Gower, M C

    1982-09-01

    We have demonstrated the use of phase-conjugate stimulated Brillouin scattering mirrors to produce high-quality, short-pulse KrF laser beams from angular multiplexed and regenerative amplifiers. The mirror was also shown to isolate systems optically from amplifier spontaneous emission. Automatic alignment of targets using this mirror as a retroreflector was also demonstrated.

  13. Stimulated Brillouin laser and frequency comb generation in high-Q microbubble resonators.

    PubMed

    Lu, Qijing; Liu, Sheng; Wu, Xiang; Liu, Liying; Xu, Lei

    2016-04-15

    We report on the stimulated Brillouin laser (SBL) and over-dense frequency comb generation in high-Q microbubble resonators (MBRs). Both first-order and cascaded SBL are achieved due to the rich high-order axial modes in the MBRs, although the free spectral range (FSR) of azimuthal mode of the MBR is severely mismatched with the Brillouin shift. The SBL is also generated by varying the internal pressure of MBR at fixed initially non-resonant pump light wavelength. In addition, over-dense frequency combs are realized with comb spacings that are one and two FSRs of aixal mode.

  14. Temperature coefficient of sideband frequency produced by polarized guided acoustic-wave Brillouin scattering in highly nonlinear fibers

    NASA Astrophysics Data System (ADS)

    Hayashi, Neisei; Suzuki, Kohei; Set, Sze Yun; Yamashita, Shinji

    2017-09-01

    We measured the temperature dependence of the polarized guided acoustic-wave Brillouin scattering (GAWBS) spectrum using a highly nonlinear fiber. The temperature coefficient is 168 kHz/K, which is 1.7 times larger than that of small-core photonic crystal fibers. This result indicates that highly temperature-sensitive GAWBS-based sensing is feasible.

  15. Time-domain Brillouin scattering for the determination of laser-induced temperature gradients in liquids

    NASA Astrophysics Data System (ADS)

    Chaban, Ievgeniia; Shin, Hyun D.; Klieber, Christoph; Busselez, Rémi; Gusev, Vitalyi E.; Nelson, Keith A.; Pezeril, Thomas

    2017-07-01

    We present an optical technique based on ultrafast photoacoustics to determine the local temperature distribution profile in liquid samples in contact with a laser heated optical transducer. This ultrafast pump-probe experiment uses time-domain Brillouin scattering (TDBS) to locally determine the light scattering frequency shift. As the temperature influences the Brillouin scattering frequency, the TDBS signal probes the local laser-induced temperature distribution in the liquid. We demonstrate the relevance and the sensitivity of this technique for the measurement of the absolute laser-induced temperature gradient of a glass forming liquid prototype, glycerol, at different laser pump powers—i.e., different steady state background temperatures. Complementarily, our experiments illustrate how this TDBS technique can be applied to measure thermal diffusion in complex multilayer systems in contact with a surrounding liquid.

  16. Diode Pumped Fiber Laser

    DTIC Science & Technology

    1983-07-01

    d AFWU.-TR-83-niO 00 H CO CO iH <^ DIODE PUMPED FIBER LASER Edward L. Glnzton Laboratory Stanford University Stanford, California 94305...RECIPIf NT’S CATALOG NUMBER 4. TITLE Cand Sub(i(/e; DIODE PUMPED FIBER LASER 5 TYPE OF REPORT & PERIOD COVERED Interim Report...external optical cavity made of two miniature flat mirrors, and end- pumped either at 514.5 nm (argon-ion laser ) or near 818 nm ( laser diode ). Coherent

  17. Modeling the effects of laser-beam smoothing on filamentation and stimulated Brillouin backscattering

    SciTech Connect

    Berger, R.L.; Kaiser, T.B.; Lasinski, B.F.

    1996-06-01

    Using the three-dimensional code (F3D), the authors compute the filamentation and backscattering of laser light. The results show that filamentation can be controlled and stimulated Brillouin backscattering (SBBS) can be reduced by using random phase plates (RPP) and small f-numbers or smoothing by spectral dispersion (SSD) with large bandwidth. An interesting result is that, for uniform plasmas, the SBBS amplification takes place over several laser axial coherence lengths (coherence length = speckle length).

  18. Characterization of temperature-dependent birefringence in polarization maintaining fibers based on Brillouin dynamic gratings

    NASA Astrophysics Data System (ADS)

    Kim, Yong Hyun; Song, Kwang Yong

    2015-07-01

    Temperature dependence of birefringence in various types of polarization-maintaining fibers (PMF's) is rigorously investigated by the spectral analysis of Brillouin dynamic grating (BDG). PANDA, Bowtie, and PM photonic crystal fibers are tested in the temperature range of -30 to 150 ºC, where nonlinear temperature dependence is quantified for each fiber to an accuracy of ±7.6 × 10-8. It is observed that the amount of deviation from the linearity varies according to the structural parameters of the PMF's and the existence of acrylate jacket. Experimental confirmation of the validity of the BDG-based birefringence measurement is also presented in comparison to the periodic lateral force method.

  19. Study of optical fibers strain-temperature sensitivities using hybrid Brillouin-Rayleigh system

    NASA Astrophysics Data System (ADS)

    Kishida, Kinzo; Yamauchi, Yoshiaki; Guzik, Artur

    2014-03-01

    In this paper, the most recent progress as well as challenges of distributed optical fiber sensing (DOFS) in industrial applications is discussed. Compared to the vast market of sensors used to measure strain or temperature, the success of distributed optical fiber sensing (DOFS) at the industrial level is very limited, at best. One of the reasons for this lack of the wider acceptance is the mismatch between the commercially available systems and actual industrial requirements, especially for the spatial resolution and precision. These requirements are organized and clarified in the paper. It also describes the hybrid Brillouin-Rayleigh system, which exhibits capabilities surpassing those of strain gauges. The principles of the system are illustrated considering the fiber calibration methodology. Formulas required for determining strain, temperature, and hydro-pressure are derived and discussed. Finally, the examples of applications are presented.

  20. High spatial resolution, dynamic, and distributed fiber optic strain sensing based on phasorial Brillouin dynamic gratings reflectometry

    NASA Astrophysics Data System (ADS)

    Bergman, A.; Langer, T.; Tur, M.

    2016-05-01

    We present a novel fiber-optic sensing technique based on the distributed measurement of Brillouin-induced phase-shift in the reflection from Brillouin dynamic gratings in polarization-maintaining fibers. Subject to signal to noise considerations, the strain sensitivity of the phase-shift in the reflection of a pulsed probe, orthogonally polarized to the gratings-generating pumps, is independent of the pulse width, suggesting the potential to achieve higher spatial resolutions than those offered by slope-assisted, phasorial Brillouin sensing techniques in standard single-mode fibers. We report the measurement of 500Hz strain vibrations (at a sampling rate of 1MHz) with a spatial resolution of 20cm.

  1. Brillouin scattering signal in polymer optical fiber enhanced by exploiting pulsed pump with multimode-fiber-assisted coupling technique.

    PubMed

    Mizuno, Yosuke; Hayashi, Neisei; Nakamura, Kentaro

    2013-05-01

    A cost-effective technique for coupling a polymer optical fiber (POF) with 50 μm core diameter to a silica single-mode fiber (SMF) with 8 μm core diameter is proposed, which can, by exploiting a multimode fiber with 50 μm core diameter, avoid the damage or burning at the butt-coupled POF/SMF interface. Using this coupling technique, we also show that the Brillouin signal in a POF can be enhanced by combined use of pulsed pump and an erbium-doped fiber amplifier. When the pulsed pump with average optical power of 18 dBm (63 mW), duty ratio of 15%, and pulse period of 2 μs is launched into a 200 m-long POF, 4 dB enhancement of the Stokes power is obtained compared to that with 18 dBm continuous wave pump. The relatively small enhancement is probably caused by the high Brillouin threshold of POFs. The Stokes power dependence on duty ratio is nonmonotonic, which might originate from a longer phonon lifetime in POFs than that in silica SMFs.

  2. First field demonstration of end-reflection assisted Brillouin analysis for in-service loss monitoring of branched fibers in PONs

    NASA Astrophysics Data System (ADS)

    Kito, Chihiro; Takahashi, Hiroshi; Toge, Kunihiro; Manabe, Tetsuya

    2015-09-01

    The in-service loss monitoring of branched fibers in passive optical networks (PONs) is demonstrated in the field for the first time. End-reflection assisted Brillouin analysis employing a frequency shift averaging technique compensated for the variation in the Brillouin gain profile of installed optical cables. Complete loss monitoring for individual branched fibers in deployed PONs was successfully achieved.

  3. Nd:YAP laser pulse compression by three-stage transient stimulated Brillouin and Raman scattering

    NASA Astrophysics Data System (ADS)

    Kubeček, V.; Hamal, K.; Procházka, I.; Buzelis, R.; Girdauskas, V.; Dementiev, A.

    1991-08-01

    There is a continuous effort to generate stable, powerful picosecond laser pulses for application in spectroscopy, nonlinear optics and parametric light generation, as well. One of the possible methods is the compression of longer nanosecond laser pulses by stimulated Brillouin and stimulated Raman scattering. The advantages of such a technique, in comparison to the used mode locked picosecond lasers, are as follows: the absence of the active and/or passive mode lockers used to generate a train of picosecond pulses, and the absence of a fast electrooptical shutter used to select a single pulse from a train of pulses. The application of stimulated Brillouin and stimulated Raman scattering permits to generate picosecond pulses in the wavelength regions not covered by mode locked lasers. Of special interest is the wavelength region of 0·8 μm, which may be amplified by the attractive Titanium Sapphire lasers. In this paper we are summarizing our results in theoretical modelling and in real generation of picosecond pulses by means of cascaded stimulated Brillouin and Raman scattering. The models of scattering processes have been investigated. The stable generation of 5, 7, 3 picosecond pulses have been optimized for the wavelengths of 0·8, 0·64 and 0·54 μm, respectively. In all these cases, the pulses exhibited the far field pattern close to Gaussian, with the pulse energy ranging from 0·2 to 1 mJ.

  4. Tunable random fiber laser

    SciTech Connect

    Babin, S. A.; Podivilov, E. V.; El-Taher, A. E.; Harper, P.; Turitsyn, S. K.

    2011-08-15

    An optical fiber is treated as a natural one-dimensional random system where lasing is possible due to a combination of Rayleigh scattering by refractive index inhomogeneities and distributed amplification through the Raman effect. We present such a random fiber laser that is tunable over a broad wavelength range with uniquely flat output power and high efficiency, which outperforms traditional lasers of the same category. Outstanding characteristics defined by deep underlying physics and the simplicity of the scheme make the demonstrated laser a very attractive light source both for fundamental science and practical applications.

  5. Robust, Brillouin Active Embedded Fiber-Is-The-Sensor System in Smart Composite Structures

    NASA Technical Reports Server (NTRS)

    Yu, Chung

    1996-01-01

    Extensive review of our proposed sensing scheme, based mainly on the forward Guided Acoustic Wave Brillouin Scattering (GAWBS) with backward stimulated Brillouin scattering (sBs) as an auxiliary scheme for system fault tolerance has been completed during this project period. This preliminary study is conducted for a number of reasons. The most significant reasons lie in the essential capability of the system to measure temperature and pressure. These two measurands have been proposed to be sensed by sBs in our proposal. Temperature and pressure/strain are important measurands in structural monitoring, so that the effectiveness of sensing by sBs needs to be further examined. It has been pointed out initially that sBs shift will be dependent on temperature and pressure/strain simultaneously. The shift versus temperature or strain is linear. Now, the question is how can these two measurands be separated when sBs is used to sense an environment, in which both temperature and strain are changing simultaneously. Typical sBs shift plotted versus strain and varying temperature is shown in Fig. 1. As is clear, a fiber initially stressed will relax with rising temperature. This is verified by a displacement to the right with rising temperature of the sBs shift vs strain curves in the figure. A way to circumvent this ambiguity is by employing two fibers, one pre-stressed and the other is a free fiber. The latter will measure temperature and subtracting data in the latter fiber from those of the former will give us net strain readings. This is a laborious approach, since it involves the use of two identical fibers, and this is hard to accomplish, especially when many sensors are needed. Additional multiplexing of the data stream for data subtraction becomes a necessity.

  6. Potential of Brillouin scattering in polymer optical fiber for strain-insensitive high-accuracy temperature sensing.

    PubMed

    Mizuno, Yosuke; Nakamura, Kentaro

    2010-12-01

    We investigated the dependences of Brillouin frequency shift (BFS) on strain and temperature in a perfluorinated graded-index polymer optical fiber (PFGI-POF) at 1.55 μm wavelength. They showed negative dependences with coefficients of -121.8 MHz/% and -4.09 MHz/K, respectively, which are -0.2 and -3.5 times as large as those in silica fibers. These unique BFS dependences indicate that the Brillouin scattering in PFGI-POFs has a big potential for strain-insensitive high-accuracy temperature sensing.

  7. Stimulated Brillouin scattering mirror system, high power laser and laser peening method and system using same

    DOEpatents

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2007-04-24

    A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

  8. Single-crystal Brillouin spectroscopy with CO{sub 2} laser heating and variable q

    SciTech Connect

    Zhang, Jin S.; Bass, Jay D.; Zhu, Gaohua

    2015-06-15

    We describe a Brillouin spectroscopy system integrated with CO{sub 2} laser-heating and Raman spectroscopic capabilities. Temperature is determined by measurements of the grey-body thermal radiation emitted by the hot sample, with the system response calibrated relative to a standard tungsten ribbon lamp. High-pressure laser-heating Brillouin scattering measurements of acoustic velocities on liquid water and ice compressed in a diamond-anvil cell were performed at temperatures up to 2500 ± 150 K at high pressure. Single-crystal laser-heating Brillouin measurements were made on the (111) plane of San Carlos olivine at ∼13 GPa, 1300 ± 200 K. The pressure as measured by ruby fluorescence is shown to be within ±0.5 GPa of the pressure on the olivine sample during laser heating when KCl and KBr are used as pressure-transmitting media. In addition, the system is designed for continuously variable scattering angles from forward scattering (near 0° scattering angle) up to near back scattering (∼141°). This novel setup allows us to probe a wide range of wave vectors q for investigation of phonon dispersion on, for example, crystals with large unit cells (on the scale of hundreds of nm)

  9. Single-crystal Brillouin spectroscopy with CO2 laser heating and variable q

    NASA Astrophysics Data System (ADS)

    Zhang, Jin S.; Bass, Jay D.; Zhu, Gaohua

    2015-06-01

    We describe a Brillouin spectroscopy system integrated with CO2 laser-heating and Raman spectroscopic capabilities. Temperature is determined by measurements of the grey-body thermal radiation emitted by the hot sample, with the system response calibrated relative to a standard tungsten ribbon lamp. High-pressure laser-heating Brillouin scattering measurements of acoustic velocities on liquid water and ice compressed in a diamond-anvil cell were performed at temperatures up to 2500 ± 150 K at high pressure. Single-crystal laser-heating Brillouin measurements were made on the (111) plane of San Carlos olivine at ˜13 GPa, 1300 ± 200 K. The pressure as measured by ruby fluorescence is shown to be within ±0.5 GPa of the pressure on the olivine sample during laser heating when KCl and KBr are used as pressure-transmitting media. In addition, the system is designed for continuously variable scattering angles from forward scattering (near 0° scattering angle) up to near back scattering (˜141°). This novel setup allows us to probe a wide range of wave vectors q for investigation of phonon dispersion on, for example, crystals with large unit cells (on the scale of hundreds of nm).

  10. Effect of laser beam filamentation on coexisting stimulated Raman and Brillouin scattering

    SciTech Connect

    Sharma, R. P.; Vyas, Ashish; Kishor Singh, Ram

    2013-10-15

    This paper presents the study of stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) when both of these processes are coexisting and pump laser beam initial power is more than filamentation threshold. On account of the ponderomotive nonlinearity, the pump laser beam gets filamented, and both the scattering processes (SRS and SBS) get affected. Simultaneous presence of SRS and SBS (five wave interaction case) also affect the pump filamentation process due to pump depletion. Both the scattering processes (SRS and SBS) are enhanced due to filamentation of laser beam. Results are also compared with the three wave interaction case (either SRS or SBS) with and without filamentation.

  11. Experimental Evidence of the Collective Brillouin Scattering of Multiple Laser Beams Sharing Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Neuville, C.; Tassin, V.; Pesme, D.; Monteil, M.-C.; Masson-Laborde, P.-E.; Baccou, C.; Fremerye, P.; Philippe, F.; Seytor, P.; Teychenné, D.; Seka, W.; Katz, J.; Bahr, R.; Depierreux, S.

    2016-06-01

    The indirect-drive scheme to inertial confinement fusion uses a large number of laser beams arranged in a symmetric angular distribution. Collective laser plasma instabilities can therefore develop that couple all the incident laser waves located in a cone to the daughter wave growing along the cone symmetry axis [D. F. DuBois et al., Phys. Fluids B 4, 241 (1992)]. With complementary diagnostics of Thomson scattering and of the scattered light, we demonstrate the occurrence of collective stimulated Brillouin sidescattering driving collective acoustic waves in indirect-drive experiments.

  12. Reduced Brillouin scattering from multiline CO2 laser interaction with a plasma

    NASA Astrophysics Data System (ADS)

    Giles, R.; Fedosejevs, R.; Offenberger, A. A.

    1982-08-01

    Experimental verification of reduced stimulated Brillouin scattering (SBS) is reported for multiline CO2 laser radiation interacting with high-density plasma. For long-pulse (40-nsec) irradiation SBS was observed to decrease from 15% to a negligible level when the spectrum of the incident laser pulse was changed from 1 to 2 or more well-separated frequencies. Results for both long- and short-pulse multiline laser conditions are in general accord with the expected behavior for varying Δωγ0, where Δω is the frequency separation and γ0 is the homogeneous growth rate.

  13. Mandel'shtam-Brillouin scattering of laser light as a remote sensing tool.

    NASA Technical Reports Server (NTRS)

    Daniels, A.

    1972-01-01

    The mathematical relations regarding the intensity of scattered light are derived. The nature of density inhomogeneities in air is discussed together with scattering due to moving isothermal pressure fluctuations, the spectral distribution of scattering from static isobaric density fluctuations, and applications of Mandel'shtam-Brillouin (M-B) scattering to atmospheric sensing. It is concluded that M-B scattering of laser light from the atmosphere has an outstanding potential for remote atmospheric sensing.

  14. Diode Pumped Fiber Laser.

    DTIC Science & Technology

    1984-12-01

    molybdium oxide ( GMO ). The best diameter variations obtained so far are on the order of 1%. It is expected that these fibers should exhibit lower...that the absorbed pump power at threshold is given by "P:" hvp 6, 1Pth = (9) O-rf 21 J(0) where SJ 1(0) =J 1(0, 0, ) =ffj soI (x, y, z) ro(x, y, z) dv...epoxy, the argon laser bean ) was first aligned through a fiber at a low power level and then slowly increased. For preliminary tests the laser cavity

  15. Discontinuous Brillouin strain monitoring of small concrete bridges: comparison between near-to-surface and smart FRP fiber installation techniques

    NASA Astrophysics Data System (ADS)

    Bastianini, Filippo; Rizzo, Andrea; Galati, Nestore; Deza, Ursula; Nanni, Antonio

    2005-05-01

    Brillouin fiber optic sensing is a promising technology for Structural Health Monitoring (SHM) whose diffusion is however at present reduced by the unavailability of proper sensor products and established installation techniques specifically aimed at the building industry. Due to its intrinsic distributed sensing capability, Brillouin systems can individually measure the deformation of any single segment of considerable lengths of single-mode fiber. In addition, Brillouin retains all the other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and electro-magnetic interference rejection. These advantages, especially considering that the required sensors are really low cost, make the system particularly attractive for periodical ("discontinuous") strain monitoring of unattended infrastructures that might be exposed to ageing and vandalism damages. Despite the high equipment cost, the technique can become economically convenient when the same initial investment can be amortized over a number of applications that can be monitored periodically using the same device. This work presents a comparison between two different Brillouin sensor installation techniques: Near-to-Surface Fiber (NSF) embedding and smart-FRP sensor bonding. Both systems have been experimented in the field on small Reinforced Concrete (RC) bridges subject to a diagnostic load test. The obtained results clearly highlight the advantages of the smart-FRP system, in terms of performance enhancements, installation cost, and time reduction.

  16. Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times

    SciTech Connect

    Korotkevich, Alexander O.; Lushnikov, Pavel M.; Rose, Harvey A.

    2015-01-15

    We developed a linear theory of backward stimulated Brillouin scatter (BSBS) of a spatially and temporally random laser beam relevant for laser fusion. Our analysis reveals a new collective regime of BSBS (CBSBS). Its intensity threshold is controlled by diffraction, once cT{sub c} exceeds a laser speckle length, with T{sub c} the laser coherence time. The BSBS spatial gain rate is approximately the sum of that due to CBSBS, and a part which is independent of diffraction and varies linearly with T{sub c}. The CBSBS spatial gain rate may be reduced significantly by the temporal bandwidth of KrF-based laser systems compared to the bandwidth currently available to temporally smoothed glass-based laser systems.

  17. Single laser pulse compression via strongly coupled stimulated Brillouin scattering in plasma

    SciTech Connect

    Peng, H.; Wu, Z. H.; Zhang, Z. M.; Zuo, Y. L.; Zhou, K. N.; Su, J. Q.

    2016-07-15

    Laser amplification in plasma, including stimulated Raman scattering amplification and strongly coupled stimulated Brillouin scattering (sc-SBS) amplification, is very promising to generate ultrahigh-power and ultrashort laser pulses. But both are quite complex in experiments: at least three different laser pulses must be prepared; temporal delay and spatial overlap of these three pulses are difficult. We propose a single pulse compression scheme based on sc-SBS in plasma. Only one moderately long laser is applied, the front part of which ionizes the gas to produced plasma, and gets reflected by a plasma mirror at the end of the gas channel. The reflected front quickly depletes the remaining part of the laser by sc-SBS in the self-similar regime. The output laser is much stronger and shorter. This scheme is at first considered theoretically, then validated by using 1D PIC simulations.

  18. [INVITED] State of the art of Brillouin fiber-optic distributed sensing

    NASA Astrophysics Data System (ADS)

    Motil, Avi; Bergman, Arik; Tur, Moshe

    2016-04-01

    Fiber-optic distributed sensing, employing the Brillouin effect, is already a commercially available measurement technique for the accurate estimation of the static strain/temperature fields along tens of kilometers with a spatial resolution of the order of a meter. Furthermore, relentless research efforts are paving the way to even much wider usability of the technique through recently achieved enhanced performance in each of its critical dimensions: measurement range has been extended to hundreds of kilometers; spatial resolution is of the order of a centimeter or less, signal to noise ratio has been significantly improved; fast dynamic events can be captured at kHz's sampling rates; and a much better understanding of the underlying physics has been obtained, along with the formulation of figures of merit, and the preparation and early adoption of appropriate standards and guidelines. This paper describes the basics, as well as the state of the art, of the leading Brillouin interrogation methods, with emphasis on the significant progress made in the last 3 years. It also includes a short introduction to coding, which has proven instrumental in many of the recently obtained performance records.

  19. Distributed and dynamic monitoring of 4km/sec waves using a Brillouin fiber optic strain sensor

    NASA Astrophysics Data System (ADS)

    Peled, Yair; Yaron, Lior; Motil, Avi; Tur, Moshe

    2013-05-01

    We report a Brillouin-based fully distributed and dynamic monitoring of a strain wave, propagating at a speed of ~4km/sec in a 6m long fiber. Using an audio speaker, a mechanical impulse was introduced to one end of a 6m long optical fiber, initiating a strain wave propagating towards the other fixed end of the fiber. Employing a simplified version of the Slope-Assisted Brillouin Optical Time Domain Analysis (SA-BOTDA) technique, the whole length of the fiber was interrogated every 1μs (before averaging). A dynamic spatially and temporally continuous map of the strain was obtained, from which the wave velocity could be deduced. With a trade-off among sampling rate, range and signal to noise ratio, kHz sampling rates and hundreds of meters of range can be covered with spatial resolutions down to a few centimeters.

  20. Thulium Fiber Laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard Leious, Jr.

    The Thulium Fiber Laser (TFL) has been studied as a potential alternative to the conventional Holmium:YAG laser (Ho:YAG) for the treatment of kidney stones. The TFL is more ideally suited for laser lithotripsy because of the higher absorption coefficient of the emitted wavelength in water, the superior Gaussian profile of the laser beam, and the ability to operate at arbitrary temporal pulse profiles. The higher absorption of the TFL by water helps translate into higher ablation of urinary stones using less energy. The Gaussian spatial beam profile allows the TFL to couple into fibers much smaller than those currently being used for Ho:YAG lithotripsy. Lastly, the ability of arbitrary pulse operation by the TFL allows energy to be delivered to the stone efficiently so as to avoid negative effects (such as burning or bouncing of the stone) while maximizing ablation. Along with these improvements, the unique properties of the TFL have led to more novel techniques that have currently not been used in the clinic, such as the ability to control the movement of stones based on the manner in which the laser energy is delivered. Lastly, the TFL has led to the development of novel fibers, such as the tapered fiber and removable tip fiber, to be used for lithotripsy which can lead to safer and less expensive treatment of urinary stones. Overall, the TFL has been demonstrated as a viable alternative to the conventional Ho:YAG laser and has the potential to advance methods and tools for treatment of kidney stones.

  1. Distributed temperature sensing based on birefringence effect on transient Brillouin grating in a polarization-maintaining photonic crystal fiber.

    PubMed

    Dong, Yongkang; Bao, Xiaoyi; Chen, Liang

    2009-09-01

    We demonstrate a time-domain distributed temperature sensing based on birefringence effect on transient Brillouin grating (TBG) in a polarization-maintaining photonic crystal fiber (PM-PCF), which uses two short pump pulses (2 ns) to excite a TBG and a long probe pulse (6 ns) to map the transient Brillouin grating spectrum (TBGS) associated with the birefringence. The 2 ns pump pulses defines a spatial resolution of 20 cm and a temperature measurement range of a few hundred degrees Celsius, and the long probe pulse provides a narrow TBGS with a temperature resolution of 0.07 degrees C.

  2. Simultaneous measurement of strain and temperature using a polarization-maintaining photonic crystal fiber with stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Zhang, Hongying; Yuan, Zhijun; Liu, Ziye; Gao, Wei; Dong, Yongkang

    2017-01-01

    We demonstrate the simultaneous and distributed sensing of temperature and strain by combining the Brillouin dynamic grating (BDG) and Brillouin gain spectrum (BGS) using a polarization-maintaining photonic crystal fiber (PM-PCF). The characterization of the birefringence frequency shift of the PM-PCF shows that it remains almost unchanged within the temperature range of 5-80 °C, which allows a temperature-insensitive strain measurement using only the BDG. Combining the BDG and BGS, we demonstrate the simultaneous measurement of temperature and strain with a spatial resolution of 20 cm over a 5-m-long PM-PCF.

  3. Bandwidth-efficient phase modulation techniques for stimulated Brillouin scattering suppression in fiber optic parametric amplifiers.

    PubMed

    Coles, J B; Kuo, B P-P; Alic, N; Moro, S; Bres, C-S; Chavez Boggio, J M; Andrekson, P A; Karlsson, M; Radic, S

    2010-08-16

    Two novel bandwidth efficient pump-dithering Stimulated Brillouin Scattering (SBS) suppression techniques are introduced. The techniques employ a frequency-hopped chirp and an RF noise source to impart phase modulation on the pumps of a two pump Fiber Optical Parametric Amplifier (FOPA). The effectiveness of the introduced techniques is confirmed by measurements of the SBS threshold increase and the associated improvements relative to the current state of the art. Additionally, the effect on the idler signal integrity is presented as measured following amplification from a two pump FOPA employing both techniques. The measured 0.8 dB penalty with pumps dithered by an RF noise source, after accruing 160 ps/nm of dispersion with 38 dB conversion gain in a two-pump FOPA is the lowest reported to date.

  4. Monolithic blue upconversion fiber laser

    NASA Astrophysics Data System (ADS)

    Gaebler, Volker; Eichler, Hans J.

    2002-06-01

    We report a monolithic low threshold 482nm Tm:ZBLAN upconversion fiber laser. The laser cavity consists of a directly coated single-mode fluoride fiber. The vapor deposit coatings significantly reduce the coupling losses and are suitable to be pumped by laser diodes. The laser operation and threshold characteristics have been investigated. The output stability and beam quality was tested.

  5. Brillouin gain spectrum dependences on temperature and strain in erbium-doped optical fibers with different erbium concentrations

    NASA Astrophysics Data System (ADS)

    Ding, Mingjie; Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2013-05-01

    Brillouin Stokes power in erbium-doped optical fibers (EDFs) can be potentially controlled by pumping, but no report has been provided on its detailed characterization. In this study, as the first step toward this goal, the Brillouin gain spectra in EDFs with three different erbium concentrations (0.72, 1.20, and 2.28 wtppt) are measured at 1.55 μm without pumping, and the Brillouin frequency shifts (BFSs) and their dependences on strain, temperature, and erbium concentration are fully investigated. In the EDF with 0.72-wtppt concentration, the BFS was 11.42 GHz, and its temperature and strain coefficients were 0.87 MHz/K and 479 MHz/%, respectively.

  6. Characterization of stimulated Brillouin scattering in a circular-core two-mode fiber using optical time-domain analysis.

    PubMed

    Li, An; Hu, Qian; Shieh, William

    2013-12-30

    We show characterization of stimulated Brillouin scattering (SBS) in a circular-core two-mode fiber (c-TMF) using Brillouin optical time-domain analysis (BOTDA) with a pulsed pump and a counterpropagating continuous wave probe. By using two free-space mode combiners (FSMCs), we can launch any combination of spatial modes into both ends of the c-TMF. Combined with coherent detection, measurement of distributed Brillouin gain spectra (BGS) is achieved for all possible counter-propagating spatial mode pairs with high spectral resolution and stability. Both intra- and inter-modal SBS are investigated for the c-TMF. The inter-modal SBS between two degenerate LP11 modes (LP11a/LP11b) is demonstrated for the first time. From the Brillouin frequency shift (BFS) measured in each intra-modal SBS, the distributed modal birefringence between non-degenerate modes (LP01/LP11) and degenerate LP11 modes is obtained. The proposed setup can potentially be used as a c-TMF based distributed Brillouin sensor.

  7. 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.

  8. A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

    NASA Astrophysics Data System (ADS)

    Loh, William; Becker, Joe; Cole, Daniel C.; Coillet, Aurelien; Baynes, Fred N.; Papp, Scott B.; Diddams, Scott A.

    2016-04-01

    We demonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6 mm diameter microrod resonator used in our experiments has a large optical mode area of ˜100 μm2, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz2 Hz-1. We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power and mode frequency. We demonstrate the ability to reduce this noise through a feedback loop that stabilizes the intracavity power.

  9. Fiber Optic Solutions for Short Pulse Lasers

    SciTech Connect

    Beach, R; Dawson, J; Liao, Z; Jovanovic, I; Wattellier, B; Payne, S; Barty, C P

    2003-01-29

    For applications requiring high beam quality radiation from efficient, compact and rugged sources, diffraction limited fiber lasers are ideal, and to date have been demonstrated at average CW power levels exceeding 100 W with near diffraction limited: output. For conventional single-core step-index single-mode fibers, this power level represents the sealing limit because of nonlinear and laser damage considerations. Higher average powers would exceed nonlinear process thresholds such as the Raman and stimulated Brillouin scattering limit, or else damage the fiber due to the high intensity level in the fiber's core. The obvious way to increase the average power capability of fibers is to increase the area of their core. Simply expanding the core dimensions of the fiber allows a straightforward power sealing due to enhanced nonlinear and power handling characteristics that scale directly with the core area. Femtosecond, chirped-pulse, fiber lasers with pulse energies greater than 1mJ have been demonstrated in the literature [2] using this technique. This output energy was still limited by the onset of stimulated Raman scattering. We have pursued an alternative and complimentary approach which is to reduce the intensity of light propagating in the core by distributing it more evenly across the core area via careful design of the refractive index profile [3]. We have also sought to address the primary issue that results from scaling the core. The enhanced power handling capability comes at the expense of beam quality, as increasing the core diameter in standard step index fibers permits multiple transverse modes to lase simultaneously. Although this problem of multimode operation can be mitigated to some extent by appropriately designing the fiber's waveguide structure, limitations such as bend radius loss, sensitivity to thermally induced perturbations of the waveguide structure, and refractive index control, all become more stringent as the core diameter grows

  10. High Power Fiber Lasers

    DTIC Science & Technology

    2012-08-02

    was measured using a Fabry Perot interferometer. Resonance wavelength output varied from 1975 to 1989 nm with an average value of 1983 nm while...wavefront sensor ,” Directed Energy Professional Society (DEPS) Solid State Diode Laser Technology Review (SSDLTR) 2011. 45. R.A. Sims, P. Kadwani, C.C.C...for all fiber diameters, pressure driven coating system using pressures from 0.8 to 1.0 bar with coating head die sizes; 375 m (entrance die) with

  11. Diode Pumped Fiber Laser.

    DTIC Science & Technology

    1987-08-01

    mounting fixture beeame soft and gradually come out of the fixture. S)me chemical reaction was takin- place between the epoxy and the dye solvent , which...loose. The solvent apparenlly did no)t affect the bonding agent used to attach the fibers inside the capillarie,. \\lthmigh individual capillarv tubes...pure solvent . was added to the cavity laser oscillation ceased, and was onlv re, ,t()red after readjuisting the orientation of the output coupler, as

  12. Optical fiber laser

    SciTech Connect

    Hakimi, F.; Po, H.; Snitzer, E.

    1987-07-14

    An optical fiber laser is described comprising: a gain cavity including a single mode optical fiber of given length having a core with a given index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprises a host glass having incorporated a laser gain material with a fluorescence spectrum having at least one broadband region in which there is at least one peak emission line; filter means optically coupled to one end of the gain cavity and reflective to radiation emitted from the gain material over a predetermined wavelength interval about the peak emission line to provide feedback in the gain cavity; an etalon filter section butt coupled to the remaining end of the gain cavity optical fiber, the etalon filter section comprising a pair of filters spaced apart in parallel by a predetermined length of material transparent to any radiation emitted from the gain cavity. The predetermined length of the transparent material is such that the etalon filter section is no longer than the distance over which the wave train energy from the fiber core remains substantially planar so that the etalon filter section is inside the divergent region to enhance feedback in the gain cavity; and means for pumping energy into the gain cavity to raise the interval energy level such that only a small part of the ion population, corresponding to a predetermined bandwidth about the peak emission line, is raised above laser threshold. The laser emits radiation only over narrow lines over a narrow wavelength interval centered about the peak emission line.

  13. Thermal strain along optical fiber in lightweight composite FOG : Brillouin-based distributed measurement and finite element analysis

    NASA Astrophysics Data System (ADS)

    Minakuchi, Shu; Sanada, Teruhisa; Takeda, Nobuo; Mitani, Shinji; Mizutani, Tadahito; Sasaki, Yoshinobu; Shinozaki, Keisuke

    2014-05-01

    Thermal strain significantly affects stability of fiber optic gyroscope (FOG) performance. This study investigates thermal strain development in a lightweight carbon fiber reinforced plastic (CFRP) FOG under thermal vacuum condition simulating space environment. First, we measure thermal strain distribution along an optical fiber in a CFRP FOG using a Brillouin-based high-spatial resolution system. The key strain profile is clarified and the strain development is simulated using finite element analysis. Finally, several constituent materials for FOG are quantitatively compared from the aspect of the maximum thermal strain and the density, confirming the clear advantage of CFRP.

  14. Real-time fast and distributed measurement of a Brillouin-inhomogeneous fiber using tailored-frequency probe in slope-assisted BOTDA

    NASA Astrophysics Data System (ADS)

    Danon, Orr; Motil, Avi; Sovran, Ido; Hadar, Raanan; Tur, Moshe

    2014-05-01

    Using a tailored-frequency probe, this paper presents a distributed slope-assisted BOTDA (SA-BOTDA) measurement of an optical fiber, bonded to a bent cantilever, where the fiber's static Brillouin Frequency Shift continuously varies along its length by an amount of the order of or larger than the Brillouin bandwidth. While standard SA-BOTDA methods, employing a fixed probe frequency, may suffer from distortions in measuring vibrations around this Brillouininhomogeneous static state, a tailored probe preserves the full dynamic range offered by the slope of Brillouin gain spectrum. The computerized measurement system is capable of real-time continuous monitoring of the strain, including averaging.

  15. 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

  16. Discrete bisoliton fiber laser

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    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.

  17. Phenomenological model of stochastic, spatiotemporal, intensity dynamics of stimulated Brillouin scattering in a two-mode optical fiber.

    PubMed

    Armstrong, Cameron R; David, John A; Thompson, John R

    2015-07-13

    We present a simple numerical model that is used in conjunction with a systematic algorithm for parameter optimization to understand the three-dimensional stochastic intensity dynamics of stimulated Brillouin scattering in a two-mode optical fiber. The primary factors driving the complex dynamics appear to be thermal density fluctuations, transverse pump fluctuations, and asymmetric transverse mode fractions over the beam cross-section.

  18. Fiber laser based hydrophone systems

    NASA Astrophysics Data System (ADS)

    Azmi, Asrul Izam; Leung, Ian; Chen, Xiaobao; Zhou, Shaoling; Zhu, Qing; Gao, Kan; Childs, Paul; Peng, Gangding

    2011-09-01

    We report our recent work on distributed feedback fiber laser based hydrophones. Some issues related to sensitivity, such as fiber laser phase condition, demodulation, and packaging, are also discussed. With the development of appropriate digital signal processing (DSP) techniques and packaging designs, an interferometric-type distributed feedback (DFB) fiber laser hydrophone system with acoustic sensitivity of 58.0 dB·re·μPa·Hz-0.5 at 1 kHz or a minimum detectable acoustic pressure below 800 μPa during field test is attained. We have also investigated an intensity-type DFB fiber laser hydrophone system and its performance.

  19. Design and analysis of single-mode tellurite photonic crystal fibers for stimulated Brillouin scattering based slow-light generation.

    PubMed

    Jain, Varsha; Sharma, Shubham; Saini, Than Singh; Kumar, Ajeet; Sinha, Ravindra Kumar

    2016-09-01

    We theoretically examine two designs of single-mode (i) Er-doped tellurite and (ii) undoped tellurite photonic crystal fiber (PCF) for generation of slow light with tunable features based on stimulated Brillouin scattering. We obtained (i) Brillouin gain up to 91 dB and time delay of ∼145  ns at maximum allowable pump power of ∼775  mW in a 2 m Er-doped tellurite PCF and (ii) Brillouin gain up to ∼88  dB and time delay of ∼154  ns at maximum allowable pump power ∼21  mW in a 100 m undoped tellurite photonic crystal fiber. Simulated results clearly indicate that the doped tellurite PCF with Er enhances the maximum allowable pump power and comparable time delay can be obtained even with reduced photonic crystal fiber length. We believe that the carried out examination and simulation have potential impact on design and development of slow-light-based photonic devices applicable in telecommunication systems, enhancement of optical forces, and quantum computing.

  20. Performance analysis of slope-assisted dynamic BOTDA based on Brillouin gain or phase-shift in optical fibers

    NASA Astrophysics Data System (ADS)

    Tu, Xiaobo; Luo, Hong; Sun, Qiao; Hu, Xiaoyang; Meng, Zhou

    2015-10-01

    This paper analyzes the performance of the slope-assisted dynamic BOTDA based on Brillouin gain or phase-shift in an experiment. Dynamic strains with frequency of 60 Hz are successfully measured with an effective sensing rate of 1 kHz over a 46 m sensing fiber in both schemes. The dynamic ranges of these two schemes are measured to be about 47 MHz (940 μ \\varepsilon ), through dynamic strain measurements while linearly sweeping the work point. The optimum work point for Brillouin gain is theoretically and experimentally proved to be {ν }B+/- \\sqrt{3}{{Δ }}{ν }B/6, not {ν }B+/- {{Δ }}{ν }B/2 as commonly known, where {ν }B corresponds to the Brillouin frequency shift and {{Δ }}{ν }B is the Brillouin linewidth. The distortion factors are also measured to stay in a quite low level in the dynamic range. These results will provide guidelines for practical dynamic strain measurements and to further improve the performance of the slope-assisted BOTDA systems.

  1. Differential Brillouin gain for improving the temperature accuracy and spatial resolution in a long-distance distributed fiber sensor.

    PubMed

    Dong, Yongkang; Bao, Xiaoyi; Li, Wenhai

    2009-08-01

    We demonstrate a 12 km differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA) using 40 ns and 50 ns pulses with DC-coupled detection. A spatial resolution of 1 m and a narrowband Brillouin gain spectrum of 33 MHz are obtained simultaneously compared with 88 MHz with the use of 10 ns pulses in a conventional BOTDA. The experimental results show that the differential Brillouin gain of a 40/50 ns pulse pair is 7 times stronger than the direct Brillouin gain of BOTDA with the use of a 10 ns pulse, and the temperature uncertainty is 0.25 degrees C compared with 1.8 degrees C for a 10 ns pulse. As the pulse-width difference decreases from 10 ns to 1 ns, corresponding to a spatial resolution from 1 m to 10 cm, the prediction of temperature uncertainty will only increase from 0.25 degrees C to 0.8 degrees C for DPP-BOTDA over a 12 km long single-mode fiber.

  2. Amplification of a seed pumped by a chirped laser in the strong coupling Brillouin regime

    SciTech Connect

    Schluck, F.; Lehmann, G.; Spatschek, K. H.

    2015-09-15

    Seed amplification via Brillouin backscattering of a long pump laser-pulse is considered. The interaction takes place in the so called strong coupling regime. Pump chirping is applied to mitigate spontaneous Raman backscattering of the pump before interacting with the seed. The strong coupling regime facilitates stronger exponential growth and narrower seeds compared to the so called weak coupling regime, although in the latter the scaling with pump amplitude is stronger. Strong coupling is achieved when the pump laser amplitude exceeds a certain threshold. It is shown how the chirp influences both the linear as well as the nonlinear amplification process. First, linear amplification as well as the seed profiles are determined in dependence of the chirping rate. In contrast to the weak coupling situation, the evolution is not symmetric with respect to the sign of the chirping rate. In the nonlinear stage of the amplification, we find an intrinsic chirp of the seed pulse even for an un-chirped pump. We show that chirping the pump may have a strong influence on the shape of the seed in the nonlinear amplification phase. Also, the influence of pump chirp on the efficiency of Brillouin seed amplification is discussed.

  3. 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.

  4. 1200°C high-temperature distributed optical fiber sensing using Brillouin optical time domain analysis.

    PubMed

    Xu, Pengbai; Dong, Yongkang; Zhou, Dengwang; Fu, Cheng; Zhang, Juwang; Zhang, Hongying; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi

    2016-07-20

    In this paper, up to 1100°C and 1200°C high-temperature distributed Brillouin sensing based on a GeO2-doped single-mode fiber (SMF) and a pure silica photonic crystal fiber (PCF) are demonstrated, respectively. The Brillouin frequency shift's (BFS) dependence on temperatures of the SMF and PCF agrees with a nonlinear function instead of a linear function, which is mainly due to the change of the acoustic velocity in a silica fiber. BFS hopping is observed in both kinds of fibers between 800°C-900°C in the first annealing process, and after that, the BFS exhibits stability and repeatability with a measurement accuracy as high as ±2.4°C for the SMF and ±3.6°C for the PCF. The BFS hopping is a highly temperature-dependent behavior, which means that a high temperature (>800°C) would accelerate this process to reach a stable state. After BFS hopping, both the SMF and PCF show good repeatability for temperatures higher than 1000°C without annealing. The process of coating burning of a silica fiber not only introduces a loss induced by micro-bending, but also imposes a compressive stress on the bare fiber, which contributes to an additional BFS variation at the temperature period of the coating burning (∼300°C-500°C).

  5. Identification of defects and strain error estimation for bending steel beams using time domain Brillouin distributed optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Bernini, R.; Fraldi, M.; Minardo, A.; Minutolo, V.; Carannante, F.; Nunziante, L.; Zeni, L.

    2006-04-01

    In recent years the use of distributed optical fiber sensors for measurements of strain in beams, by means of the Brillouin scattering effect, has been proposed. Several works pointed out the practical difficulty of this kind of measurement, connected both to theoretical and to experimental problems, e.g. mechanical characterization of optical fibers, decaying of strains in the protective coatings, spatial resolution of the Brillouin scattering, brittleness of the glass core, elastic-plastic response of the polymeric jackets, end effects and the different responses of the fiber for dilatation and contraction. Dealing with each of the above problems still requires a great research effort. However, recent literature shows that distributed optical fiber measurement techniques are extremely useful for finding qualitative responses in terms of strains. Indeed, in spite of the above-mentioned uncertainties, the great advantage of the proposed distributed measurement of strains remains evident for the safety assessment of large structures, such as bridges, tunnels, dams and pipelines, over their whole lifetimes. In view of this, in the present paper the detection of defects or damage in bending beams—by using distributed optical fiber sensors in a method based on time domain stimulated Brillouin scattering—is proposed. In particular, laboratory tests were carried out to measure the strain profile along a steel beam. Two tests were performed: the first one involves an integral steel beam, while the second experiment is performed on a damaged beam. Comparison between these two tests allows the detection of the position and the establishing of bounds on the size of the defect. At the end, the quality and accuracy of the measurements are discussed and a sensitivity analysis of the strain readings taking into account the bonding conditions at the interface between the structure and the fiber is also carried out by means a parametric numerical simulation.

  6. Distributed fiber optic sensors for monitoring reinforced concrete piles using Brillouin scattering

    NASA Astrophysics Data System (ADS)

    de Battista, N.; Kechavarzi, C.; Soga, K.

    2016-05-01

    In this paper we report on advances made in the installation and use of distributed fiber optic sensors to monitor reinforced concrete piles subjected to static load tests. Eight concrete test piles, at three construction sites in London, have recently been instrumented with embedded DFOS. The Brillouin optical time domain reflectometry (BOTDR) technique was used to measure the changes in internal strain and temperature of the piles, during concrete curing and during load testing. These data were used to assess the quality of the pile and derive the load capacity parameters to be used in the foundation design of tall buildings which are to be erected on these sites. The measurements obtained from the DFOS system agreed well with the measurements taken simultaneously using conventional point sensors embedded in the piles. Whereas the conventional sensors only provided measurements at a small number of locations within the piles, the DFOS system made it possible to record the complete strain / temperature profiles along the length of the piles.

  7. Stimulated Brillouin scattering at the second harmonic of a laser in two-ion-species plasma

    NASA Astrophysics Data System (ADS)

    Yadav, Sushila; Kaur, Sukhdeep; Tripathi, V. K.

    2008-12-01

    A high power laser (ω0, k0), propagating through a two-ion-species plasma, produces oscillatory electron velocity at the second harmonic due to V×B force. This velocity parametrically couples an ion acoustic wave (ω, k) and a scattered electromagnetic wave (ω1, k1), where ω1=ω-2ω0, k1=k-2k0 causing second harmonic Brillouin scattering. The growth rate, far above the threshold, scales linearly with laser intensity. It has maximum growth rate slightly tilted to side scattering and vanishes for back scattering. The presence of light ion species introduces linear damping on the ion mode, diminishing the growth rate of the parametric instability.

  8. A 1-Joule laser for a 16-fiber injection system

    SciTech Connect

    Honig, J

    2004-04-06

    A 1-J laser was designed to launch light down 16, multi-mode fibers (400-{micro}m-core dia.). A diffractive-optic splitter was designed in collaboration with Digital Optics Corporation (DOC), and was delivered by DOC. Using this splitter, the energy injected into each fiber varied <1%. The spatial profile out of each fiber was such that there were no ''hot spots,'' a flyer could successfully be launched and a PETN pellet could be initiated. Preliminary designs of the system were driven by system efficiency where a pristine TEM{sub 00} laser beam would be required. The laser is a master oscillator, power amplifier (MOPA) consisting of a 4-mm-dia. Nd:YLF rod in the stable, q-switched oscillator and a 9.5-mm-dia. Nd:YLF rod in the double-passed amplifier. Using a TEM{sub 00} oscillator beam resulted in excellent transmission efficiencies through the fibers at lower energies but proved to be quite unreliable at higher energies, causing premature fiber damage, flyer plate rupture, stimulated Raman scattering (SRS), and stimulated Brillouin scattering (SBS). Upon further investigation, it was found that both temporal and spatial beam formatting of the laser were required to successfully initiate the PETN. Results from the single-mode experiments, including fiber damage, SRS and SBS losses, will be presented. In addition, results showing the improvement that can be obtained by proper laser beam formatting will also be presented.

  9. Studies on High-Resolution Brillouin and Frequency Modulation Laser Absorption Spectroscopies

    NASA Astrophysics Data System (ADS)

    Pattnaik, Radha Krishna

    1992-01-01

    The discovery of quasicrystals in 1984 has invoked considerable interest in the physics of quasiperiodic layered structures. Interfaces between elastically different media modify the acoustic phonons and give rise to new modes. Observation of these modes and their dependence on structural parameters provide a direct insight into the elastic and photoelastic properties of the layered structures. Brillouin scattering is an excellent non-destructive means to detect these excitations. A simple theoretical model for the acoustic phonons in a quasiperiodic, one dimensional, Fibonacci chain is presented. The results show that the density of states is selfsimilar and the higher frequency modes are suppressed as the length of the chain is increased. Electronic energy band structure of the same chain modeled as a Kronig-Penny system is also studied and is seen to have a selfsimilar structure, and as the number of barriers is increased the lower energy states are found to exhibit localization character. Brillouin scattering from such a superlattice constructed out of layers of AlSb and GaSb is discussed and the intensity of the inelastic components is calculated. Experimental results for the first time detecting these components in a backscattering geometry enploying a triple pass Fabry Perot interferometer are presented. In the second part of this work, frequency modulation (FM) spectroscopy is extended to the important regime of multimode dye lasers. Theoretical calculations show that the edge of the laser power profile plays a decisive role and under certain circumstances can result in an FM signal that is not limited by the FWHM of the laser line. The theoretical results are demonstrated to be in excellent agreement with experimentally measured FM spectra obtained by probing the atomic sodium D_2 transition line. The measured FWHM of the signal is narrower than the laser bandwidth and is in excellent agreement with the theoretical predictions.

  10. 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.

  11. Dual-kind Q-switching of erbium fiber laser

    SciTech Connect

    Barmenkov, Yuri O. Kir'yanov, Alexander V.; Cruz, Jose L.; Andres, Miguel V.

    2014-03-03

    Two different regimes of Q-switching in the same implementation of an actively Q-switched erbium-doped fiber laser are demonstrated. Depending on the active fiber length and repetition rate of an intracavity Q-cell (acousto-optic modulator), the laser operates either in the regime of common, rather long and low-power, pulses composed of several sub-pulses or in the one of very short and powerful stimulated Brillouin scattering-induced pulses. The basic physical reason of the laser system to oscillate in one of these two regimes is the existence or absence of CW narrow-line “bad-cavity” lasing in the intervals when the Q-cell is blocked.

  12. Spatial structure and coherence properties of Brillouin scatter from CO2 laser-target interaction

    NASA Astrophysics Data System (ADS)

    Mitchel, G. R.; Grek, B.; Johnston, T. W.; Pépin, H.; Church, P.; Martin, F.

    1982-05-01

    The spatial structure and coherence properties of 10.6-μm light scattered from CO2 laser-target interactions in oblique incidence show many unexpected features. It is found that the Brillouin backscatter is neither a phase conjugate nor a ray retrace of the incident beam. Rather, it shows a preference for scattering directions other than those exactly antiparallel to the incident beam, apparently related to the angular distribution of the scattering source and also of the plasma corona that serves as the Brillouin amplifying medium. As well, the backscatter phasefront is strongly perturbed with respect to the incident phasefront. This is an indication of turbulence in the corona and/or memory of the structure in the source that is then amplified. Small-scale structures seen in the reimaged backscatter are due to phase perturbation and cannot be simply interpreted as geometric images of a (filamented) source. The phasefront of light that is scattered obliquely from the plasma is much more coherent.

  13. Fiber lasers for material processing

    NASA Astrophysics Data System (ADS)

    Shiner, Bill

    2005-03-01

    Low power fiber lasers began entering the commercial markets in the early 1990s. Since their introduction, fiber lasers have rapidly progressed in power levels level with greatly improved beam quality to the point where they now exceed any other commercial material processing laser. These lasers, with single mode operation to 1 kilowatt and multi-mode operation to beyond 20 kilowatts, have high wall plug efficiency, an extremely compact footprint, are maintenance free and have a predicted diode life beyond 100,000 hours of continuous operation. Fiber lasers are making inroads into the scientific, medical, government, and in particular, material processing markets. These lasers have greatly expanded the application umbrella due to their unparallel performance combined with the ability to operate at different wavelengths, address remote applications and be propagated great distances in fiber. In the material processing markets, fiber lasers are rapidly gaining share in the automotive, microelectronic, medical device and marking markets, to name a few. The single mode lasers are redefining process parameters that have been accepted for decades. The high brightness multimode-kilowatt class lasers are achieving speeds and depths greater than comparable powered conventional lasers while providing the only commercial material processing lasers operating beyond 6 kilowatts at the 1 micron region.

  14. Suppression of stimulated Brillouin instability of a beat-wave of two lasers in multiple-ion-species plasmas

    SciTech Connect

    Yadav, Pinki; Gupta, D. N. Avinash, K.

    2016-01-15

    Stimulated Brillouin instability of a beat-wave of two lasers in plasmas with multiple-ion-species (negative-ions) was studied. The inclusion of negative-ions affects the growth of ion-acoustic wave in Brillouin scattering. Thus, the growth rate of instability is suppressed significantly by the density of negative-ions. To obey the phase-matching condition, the growth rate of the instability attains a maxima for an appropriate scattering angle (angle between the pump and scattered sideband waves). This study would be technologically important to have diagnostics in low-temperature plasmas.

  15. Optimization of interaction conditions for efficient short laser pulse amplification by stimulated Brillouin scattering in the strongly coupled regime

    SciTech Connect

    Chiaramello, M.; Riconda, C.; Amiranoff, F.; Fuchs, J.; Grech, M.; Marquès, J.-R.; Vinci, T.; Lancia, L.; Weber, S.

    2016-07-15

    Plasma amplification of low energy, a short (∼100–500 fs) laser pulse by an energetic long (∼10 ps) pulse via strong coupling Stimulated Brillouin Backscattering is investigated with an extensive analysis of one-dimensional particle-in-cell simulations. Parameters relevant to nowadays experimental conditions are investigated. The obtained seed pulse spectra are analyzed as a function of the interaction conditions such as plasma profile, pulses delay, and seed or pulse duration. The factors affecting the amount of energy transferred are determined, and the competition between Brillouin-based amplification and parasitic Raman backscattering is analyzed, leading to the optimization of the interaction conditions.

  16. Multiwatts narrow linewidth fiber Raman amplifiers.

    PubMed

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

    2008-07-21

    Up to 4.8 W, approximately 10 MHz, 1178 nm laser is obtained by Raman amplification of a distributed feedback diode laser in standard single mode fibers pumped by an 1120 nm Yb fiber laser. More than 10% efficiency and 27 dB amplification is achieved, limited by onset of stimulated Brillouin scattering. The ratio of Raman to Brillouin gain coefficient of a fiber is identified as a figure of merit for building a narrow linewidth fiber Raman amplifier.

  17. Advanced Optical Fibers for High power Fiber lasers

    DTIC Science & Technology

    2015-08-24

    0704-0188 3. DATES COVERED (From - To) - UU UU UU UU 24-08-2015 Approved for public release; distribution is unlimited. Advanced Optical Fibers for...0946 ABSTRACT Advanced Optical Fibers for High power Fiber lasers Report Title A review of recent fiber developement for high power fiber lasers...Chapter 7 Advanced Optical Fibers for High Power Fiber Lasers Liang Dong Additional information is available at the end of the chapter http://dx.doi.org

  18. Steady state γ-ray radiation effects on Brillouin fiber sensors

    NASA Astrophysics Data System (ADS)

    Cangialosi, C.; Girard, S.; Boukenter, A.; Marin, E.; Cannas, M.; Delepine-Lesoille, S.; Marcandella, C.; Paillet, P.; Ouerdane, Y.

    2015-09-01

    Brillouin optical time-domain analysis (BOTDA) sensors offer remarkable advantages for the surveillance of the planned French deep geological radioactive wastes repository, called Cigéo1,2. In this work we study the performances of Brillouin distributed sensors in harsh environment. We evaluate the radiation tolerance of different sensor classes and their responses evolution during γ-ray exposition with 1kGy/h dose rate (to reach ~0.2MGy) and after 1, 3, 6 and 10 MGy accumulated doses. Measurements on strained Ge-doped SMF are reported to highlight the variation on Brillouin scattering proprieties, both intrinsic frequency position of Brillouin shift and its dependence on temperature and strain.

  19. Angular characteristics of the stimulated-Brillouin-scattering spectrum from a laser plasma with strong acoustic-wave damping

    SciTech Connect

    Saikia, P.

    1981-07-01

    The spectrum of stimulated Brillouin scattering from an inhomogeneous moving laser plasma is analyzed. The damping of acoustic waves and scattered electromagnetic waves is taken into account. Spectra are derived for various scattering angles and for various radii of the laser beam. For all observation angles the center of the spectral line is at an unshifted frequency. As the observation angle increases, the width of the red wing in the spectrum increases. The intensity of the scattered light is very anisotropic.

  20. Study of Brillouin scattering in a phosphosilicate optical fibre and its influence on a Raman laser operation

    SciTech Connect

    Babin, S A; Ismagulov, A E; Kablukov, S I; Podivilov, E V; Churkin, D V

    2007-05-31

    Stimulated Brillouin scattering (SBS) of single-frequency radiation in an AllWave(TM) telecommunication fibre and a phosphosilicate fibre is studied. The frequency shift and stimulated Raman gain are measured. The emission spectrum of a phosphosilicate Raman fibre laser is studied in the near-threshold regime. It is shown that SBS does not broaden the output emission spectrum of the Raman laser. (optical fibres)

  1. Controlling the stimulated Brillouin scattering of self-focusing nanosecond laser pulses in silica glasses

    SciTech Connect

    Mauger, Sarah; Berge, Luc; Skupin, Stefan

    2011-06-15

    We numerically investigate the interplay between Kerr self-focusing (SF) and transient stimulated Brillouin scattering (SBS) for nanosecond pulses in bulk silica. The influences of the input power, phase, or amplitude modulations in the pump pulse together with the incident beam shape on the filamentation dynamics are discussed. We show that appropriate amplitude modulations dividing nanosecond laser pumps into picosecond-long pulse trains inhibit SBS at any power. In contrast, phase-modulated pulses with comparable spectral width undergo multiple filamentation and earlier beam collapse due to modulational instabilities. We demonstrate, however, the existence of a critical pump bandwidth above which SBS can be efficiently suppressed by phase modulations even at high powers. This observation also holds for squared beam shapes with much broader spatial spectra, which decay more easily into multiple filaments over short distances. Intensity profiles of the reflected Stokes waves for such broad pumps are finally discussed.

  2. Method for pulse control in a laser including a stimulated brillouin scattering mirror system

    DOEpatents

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2007-10-23

    A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

  3. Stimulated Brillouin scattering of the beat wave of two lasers in a plasma

    SciTech Connect

    Panwar, Anuraj; Sharma, A. K.

    2009-09-15

    Stimulated Brillouin scattering of two collinear lasers in a plasma is investigated. Lasers exert a longitudinal ponderomotive force on electrons, imparting them oscillatory axial velocity at the beat frequency. This velocity acts as a driver for parametric excitation of an ion acoustic wave (omega,k-vector) and a noncollinear sideband electromagnetic wave (omega{sup '},k-vector{sup '}). The driver velocity v-vector{sub 0-} couples to the sideband wave to exert a ponderomotive force at (omega,k-vector) on the electrons, driving the ion acoustic wave. The density perturbation of ion acoustic wave beats with v-vector{sub 0-} to produce a nonlinear current at (omega{sup '},k-vector{sup '}), driving the sideband. In the case of finite spot size Gaussian laser beams, the beat wave has a Gaussian profile and excites an ion acoustic wave (omega,k-vector) and a backscattered TM mode (omega{sup '},k-vector{sub z}{sup '}). The growth rate scales as the product of amplitudes of the lasers and maximizes at optimum values of scattering angles. The parametric instability of difference frequency driver is stronger than the sum frequency driver.

  4. High-temperature measurement with Brillouin optical time domain analysis of an annealed fused-silica single-mode fiber.

    PubMed

    Bao, Yi; Chen, Genda

    2016-07-15

    The effect of annealing is experimentally studied for a fused silica, fully distributed fiber optic sensor based on the pulse pre-pump Brillouin optical time domain analysis (PPP-BOTDA). Within a heating rate of 4.3°C/min and 30.6°C/min, and a sustained peak temperature for 120 and 240 min, annealing extended the sensor's upper operation temperature from 800°C to 1000°C and reduced the sensor's measurement variability over a temperature range of 22°C to 1000°C with a maximum Brillouin frequency variation of 1%. The annealed sensor had a linearly decreasing Brillouin frequency sensitivity from 1.349×10-3  GHz/°C at 22°C to 0.419×10-3  GHz/°C at 1000°C. The time required to achieve a stable annealing effect decayed exponentially with annealing temperature.

  5. Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

    PubMed

    Chin, Sanghoon; Thévenaz, Luc; Sancho, Juan; Sales, Salvador; Capmany, José; Berger, Perrine; Bourderionnet, Jérôme; Dolfi, Daniel

    2010-10-11

    We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

  6. Order statistics of high-intensity speckles in stimulated Brillouin scattering and plasma-induced laser beam smoothing

    NASA Astrophysics Data System (ADS)

    Hüller, S.; Porzio, A.; Robiche, J.

    2013-02-01

    We have studied plasma-induced smoothing due to stimulated Brillouin scattering (SBS) under the aspect of the extremal statistics of smoothed laser beams. As pointed out in the work by Rose and DuBois (1994 Phys. Rev. Lett. 72 2883), scattered light can be subject to uncontrolled (or even ‘explosive’) behaviour, associated with a critical gain value for SBS. In this work we show how this critical behaviour can be predicted on the basis of the order statistics of laser speckle fields, and we analyse the transition to uncontrolled behaviour of the laser beam due to the dominance of high intensity speckles.

  7. Anti-Stokes scattering and Stokes scattering of stimulated Brillouin scattering cascade in high-intensity laser-plasma interaction

    NASA Astrophysics Data System (ADS)

    Feng, Q. S.; Liu, Z. J.; Zheng, C. Y.; Xiao, C. Z.; Wang, Q.; Zhang, H. C.; Cao, L. H.; He, X. T.

    2017-07-01

    Anti-Stokes scattering and Stokes scattering in stimulated Brillouin scattering (SBS) cascades have been researched using the Vlasov-Maxwell simulation. In high-intensity laser-plasma interactions, stimulated anti-Stokes Brillouin scattering (SABS) will occur after second stage SBS rescattering. The mechanism of SABS has been put forward to explain this phenomenon. In the early phase of SBS evolution, only first stage SBS appears and total SBS reflectivity comes from first stage SBS. However, when high-stage SBS and SABS occur, SBS reflectivity will display burst behavior and the total reflectivity comes from the SBS cascade and SABS superimposition. The SABS will compete with the SBS rescattering to determine the total SBS reflectivity. Thus, SBS rescattering including SABS is an important saturation mechanism of SBS and should be taken into account in high-intensity laser-plasma interaction.

  8. Dissipative solitons in fiber lasers

    NASA Astrophysics Data System (ADS)

    Turitsyn, S. K.; Rosanov, N. N.; Yarutkina, I. A.; Bednyakova, A. E.; Fedorov, S. V.; Shtyrina, O. V.; Fedoruk, M. P.

    2016-07-01

    Dissipative solitons (also known as auto-solitons) are stable, nonlinear, time- or space-localized solitary waves that occur due to the balance between energy excitation and dissipation. We review the theory of dissipative solitons applied to fiber laser systems. The discussion context includes the classical Ginzburg-Landau and Maxwell-Bloch equations and their modifications that allow describing laser-cavity-produced waves. Practical examples of laser systems generating dissipative solitons are discussed.

  9. Brillouin/Raman compensation of the Kerr-effect-induced bias in a nonlinear ring laser gyroscope.

    PubMed

    Luo, Zhang; Yuan, Xiaodong; Zhu, Zhihong; Liu, Ken; Ye, Weimin; Zeng, Chun; Ji, Jiarong

    2013-04-01

    In this Letter, the beat frequency at rest of a ring laser gyroscope with nonlinear effects is discussed in detail. Even without an additional intensity-stabilizing system, the random nullshift bias induced by the Kerr effect is compensated by the phase shift associated with the stimulated Brillouin/Raman scattering. And the nonlinear stimulated scattering also serves as the gain mechanism of the gyroscope. And thus the influence of the fluctuation of the injected pump intensity on the beat frequency is eliminated.

  10. Experimental Analysis of Steel Beams Subjected to Fire Enhanced by Brillouin Scattering-Based Fiber Optic Sensor Data

    PubMed Central

    Bao, Yi; Chen, Yizheng; Hoehler, Matthew S.; Smith, Christopher M.; Bundy, Matthew; Chen, Genda

    2016-01-01

    This paper presents high temperature measurements using a Brillouin scattering-based fiber optic sensor and the application of the measured temperatures and building code recommended material parameters into enhanced thermomechanical analysis of simply supported steel beams subjected to combined thermal and mechanical loading. The distributed temperature sensor captures detailed, nonuniform temperature distributions that are compared locally with thermocouple measurements with less than 4.7% average difference at 95% confidence level. The simulated strains and deflections are validated using measurements from a second distributed fiber optic (strain) sensor and two linear potentiometers, respectively. The results demonstrate that the temperature-dependent material properties specified in the four investigated building codes lead to strain predictions with less than 13% average error at 95% confidence level and that the Europe building code provided the best predictions. However, the implicit consideration of creep in Europe is insufficient when the beam temperature exceeds 800°C. PMID:28239230

  11. Experimental Analysis of Steel Beams Subjected to Fire Enhanced by Brillouin Scattering-Based Fiber Optic Sensor Data.

    PubMed

    Bao, Yi; Chen, Yizheng; Hoehler, Matthew S; Smith, Christopher M; Bundy, Matthew; Chen, Genda

    2017-01-01

    This paper presents high temperature measurements using a Brillouin scattering-based fiber optic sensor and the application of the measured temperatures and building code recommended material parameters into enhanced thermomechanical analysis of simply supported steel beams subjected to combined thermal and mechanical loading. The distributed temperature sensor captures detailed, nonuniform temperature distributions that are compared locally with thermocouple measurements with less than 4.7% average difference at 95% confidence level. The simulated strains and deflections are validated using measurements from a second distributed fiber optic (strain) sensor and two linear potentiometers, respectively. The results demonstrate that the temperature-dependent material properties specified in the four investigated building codes lead to strain predictions with less than 13% average error at 95% confidence level and that the Europe building code provided the best predictions. However, the implicit consideration of creep in Europe is insufficient when the beam temperature exceeds 800°C.

  12. 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.

  13. Temperature-compensated distributed hydrostatic pressure sensor with a thin-diameter polarization-maintaining photonic crystal fiber based on Brillouin dynamic gratings.

    PubMed

    Teng, Lei; Zhang, Hongying; Dong, Yongkang; Zhou, Dengwang; Jiang, Taofei; Gao, Wei; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi

    2016-09-15

    A temperature-compensated distributed hydrostatic pressure sensor based on Brillouin dynamic gratings (BDGs) is proposed and demonstrated experimentally for the first time, to the best of our knowledge. The principle is to measure the hydrostatic pressure induced birefringence changes through exciting and probing the BDGs in a thin-diameter pure silica polarization-maintaining photonic crystal fiber. The temperature cross-talk to the hydrostatic pressure sensing can be compensated through measuring the temperature-induced Brillouin frequency shift (BFS) changes using Brillouin optical time-domain analysis. A distributed measurement of hydrostatic pressure is demonstrated experimentally using a 4-m sensing fiber, which has a high sensitivity, with a maximum measurement error less than 0.03 MPa at a 20-cm spatial resolution.

  14. Characterization of evolution of mode coupling in a graded-index polymer optical fiber by using Brillouin optical time-domain analysis.

    PubMed

    Dong, Yongkang; Xu, Pengbai; Zhang, Hongying; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi

    2014-11-03

    A narrow bandwidth (2GHz) π-phase-shift flattop fiber Bragg grating (FBG) is proposed to achieve Brillouin optical time-domain analysis (BOTDA) for perfluorinated graded-index polymer optical fibers (GI-POFs) for the first time to best of our knowledge. Using the technique of BOTDA, we explore the evolution of mode coupling in perfluorinated GI-POFs by analyzing the Brillouin frequency shift (BFS) variation along the whole fiber, and compare them with that of silica graded index multimode fibers (GI-MMFs). The characteristics of mode coupling of GI-POFs and GI-MMFs were also investigated in terms of the speckle patterns at the output face of the two fibers. The results show that compared with silica GI-MMFs, GI-POFs exhibit more efficient mode coupling and the excellent ablility of mode scrambling regardless of alignment conditions.

  15. 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.

  16. 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.

  17. 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.

  18. Dynamical transition between weak and strong coupling in Brillouin laser pulse amplification

    SciTech Connect

    Schluck, F.; Lehmann, G.; Müller, C.; Spatschek, K. H.

    2016-08-15

    Short laser pulse amplification via stimulated Brillouin backscattering in plasma is considered. Previous work distinguishes between the weakly and strongly coupled regime and treats them separately. It is shown here that such a separation is not generally applicable because strong and weak coupling interaction regimes are entwined with each other. An initially weakly coupled amplification scenario may dynamically transform into strong coupling. This happens when the local seed amplitude grows and thus triggers the strongly driven plasma response. On the other hand, when in a strong coupling scenario, the pump pulse gets depleted, and its amplitude might drop below the strong coupling threshold. This may cause significant changes in the final seed pulse shape. Furthermore, experimentally used pump pulses are typically Gaussian-shaped. The intensity threshold for strong coupling may only be exceeded around the maximum and not in the wings of the pulse. Also here, a description valid in both strong and weak coupling regimes is required. We propose such a unified treatment which allows us, in particular, to study the dynamic transition between weak and strong coupling. Consequences for the pulse forms of the amplified seed are discussed.

  19. Ultrafast fiber lasers: practical applications

    NASA Astrophysics Data System (ADS)

    Pastirk, Igor; Sell, Alexander; Herda, Robert; Brodschelm, Andreas; Zach, Armin

    2015-05-01

    Over past three decades ultrafast lasers have come a long way from the bulky, demanding and very sensitive scientific research projects to widely available commercial products. For the majority of this period the titanium-sapphire-based ultrafast systems were the workhorse for scientific and emerging industrial and biomedical applications. However the complexity and intrinsic bulkiness of solid state lasers have prevented even larger penetration into wider array of practical applications. With emergence of femtosecond fiber lasers, based primarily on Er-doped and Yb-doped fibers that provide compact, inexpensive and dependable fs and ps pulses, new practical applications have become a reality. The overview of current state of the art ultrafast fiber sources, their basic principles and most prominent applications will be presented, including micromachining and biomedical implementations (ophthalmology) on one end of the pulse energy spectrum and 3D lithography and THz applications on the other.

  20. Fiber Laser Array

    DTIC Science & Technology

    2004-01-01

    telecommunications market and do not emphasize high powers. Because high power applications are of significant interest to the Air Force, we were interested in fiber...available from NTIC . 9. T.B. Simpson, A. Gavrielides and P. Peterson, “Extraction Characteristics of a Dual Fiber Compound Cavity,” Optics Express 10

  1. Optical transmission through a polarization preserving single mode optical fiber at two Ar(+) laser wavelengths

    NASA Technical Reports Server (NTRS)

    Tedjojuwono, Ken K.; Hunter, William W., Jr.

    1989-01-01

    The transmission characteristics of two Ar(+) laser wavelengths through a twenty meter Panda type Polarization Preserving Single Mode Optical Fiber (PPSMOF) were measured. The measurements were done with both single and multi-longitudinal mode radiation. In the single longitudinal mode case, a degrading Stimulated Brillouin Scattering (SBS) is observed as a backward scattering loss. By choosing an optimum coupling system and manipulating the input polarization, the threshold of the SBS onset can be raised and the transmission efficiency can be increased.

  2. Fiber optic and laser sensors VII

    SciTech Connect

    Udd, E.; De Paula, R.P.

    1989-01-01

    This book contains articles on fiber optic and laser sensors. Included are these topics: Fiber optic sensor development at universities, Fiber optic sensing techniques, Magnetics, and Acoustics and pressure sensors.

  3. 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).

  4. Actively Q-switched fiber lasers: Switching dynamics and nonlinear processes

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Xu, Chang-Qing

    The Q-switching characteristics of actively Q-switched fiber lasers, especially the inconsistency of experimental observations with traditional Q-switching theory, are reviewed first in this paper. Based on a few typical high-power Q-switched rare-earth-doped fiber lasers, the switching dynamics in the linear and ring fiber cavities is then systematically illustrated under different fiber, pumping and switching conditions by using the traveling wave method, which leads to a new understanding of Q-switched fiber lasers. In particular, the switching-induced perturbation and its influence on the Q-switched outputs are emphasized, and some experimental demonstrations are shown for the purpose of comparison. Nonlinearity is an important concern in these lasers due to the high-power optical pulses confined in small fiber cores. In the second part of this paper, some nonlinear effects, such as self-phase modulation (SPM), four-wave mixing (FWM), stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), in Q-switched fiber lasers are discussed. In particular, their temporal and spectral influences on the Q-switched outputs are analyzed experimentally and theoretically. These theoretical analyses and experimental demonstrations provide a complete picture of the switching dynamics and optical nonlinear processes in Q-switched fiber lasers, and are hence important for laser optimization and control.

  5. 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.

  6. 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.

  7. High quality tunable Brillouin optoelectronic oscillator

    NASA Astrophysics Data System (ADS)

    Mousa, Mohamed; Ahmed, Mahmoud H.; Hassan, Kamel M. M.; Abouelatta, Mohamed; Afifi, Abdelrahman E.

    2016-09-01

    An optical scheme to improve the quality of an RF signal is proposed. The 6 dB linewidth is reduced to sub hertz and the low frequency noise below 1 KHz is reduced about 10 dB. The scheme utilizes a Brillouin-semiconductor optical amplifier (SOA) ring laser fitted with an RF intensity modulator and an APD detector. The experimental results show cavity modes with FSR of 30.57 KHz due to Brillouin fiber length of 6.6 km and 6 dB bandwidth of 780 mHz typical of Brillouin lasers. The gain of the SOA balances out most of the losses in the ring mainly that due to the RF modulator. The modulated optical signal beats at the APD. The optical loop acts as a cavity filter to the RF signal. A jitter in the cavity resonances due to temperature variations is completely eliminated from the output beat signal. There is a 10 dB increase in the phase noise at the FSR frequency and its harmonics. The setup is tested with signals generated by different sources and to frequencies up to 10 GHz, the limit of the APD. Sources with RF linewidth less than the optical FSR produces one output mode with sub-hertz line width. For larger line width signals more than one RF frequency is produced, separated by the FSR, each showing the Brillouin linewidth.

  8. Numerical modeling of the phase-conjugate laser with an intra-cavity stimulated Brillouin scattering mirror: Q-switching mode

    NASA Astrophysics Data System (ADS)

    Yashkir, Yuri

    2006-04-01

    We present a new computer numerical model of the phase-conjugate laser, utilizing an intra-cavity Stimulated Brillouin Scattering (SBS) element. The modelled laser system includes the active laser crystal which is placed between the output coupler mirror and a stimulated Brillouin scattering cell. The numerical model includes a set of rate equations for the active crystal inverse population, and for the photon density inside the laser cavity. The SBS backscattering model is based on a reduced set of coupled equations for electromagnetic fields for two waves (a pump wave and an SBS wave) propagating in opposite directions. The numerical integration of the set of equations simulates in detail the temporal dynamics of the laser. A wide range of realistic system parameters was numerically investigated. Different laser regimes (from a quasi -CW mode to a Q-switched mode) were numerically tested. The method of numerical modelling of such laser system can be efficiently used for an optimal laser design.

  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. Experimental investigation of stimulated Raman and Brillouin scattering instabilities driven by two successive collinear picosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Rousseaux, C.; Baton, S. D.; Bénisti, D.; Gremillet, L.; Loupias, B.; Philippe, F.; Tassin, V.; Amiranoff, F.; Kline, J. L.; Montgomery, D. S.; Afeyan, B. B.

    2016-04-01

    Backward stimulated Raman and Brillouin scattering (SRS and SBS) are experimentally investigated by using two successive 1-μm, 1.5-ps FWHM laser pulses. The collinear pulses, separated by 3 or 6 ps and of moderate laser intensities (˜2 ×1016W c m-2 ), are fired into a preionized He plasma of density ˜2.5 -6 ×1019c m-3 . The electron plasma waves and ion acoustic waves, respectively driven by SRS and SBS, are analyzed through space- and time-resolved Thomson scattering. Depending on the laser and plasma parameters, we observe the effect of the first pulse on the time-resolved SRS and SBS signals of the second pulse. The measurements are found to qualitatively agree with the results of a large-scale particle-in-cell simulation.

  11. Developing Pulsed Fiber Lasers

    DTIC Science & Technology

    2007-06-15

    moving pupil imaging system. Y. Kawagoe et al. furthered the research in the early 80’s by using a rotating aperture at the Fourier ...dependent terms in Eq. 16 by their respective Fourier Series Eq. 16 can be written in the following form, ( ) ( ) ( ) ( )( ) ( ) ( ) ( )( )( ) 1 2 0...Asakura, “Speckle reduction by a rotating aperture at the Fourier transform plane,” Opt. Lasers in Eng., 3 197-218, (1982) [8] T. Iwai, N. Takai

  12. 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.

  13. Cladded single crystal fibers for high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Kim, W.; Shaw, B.; Bayya, S.; Askins, C.; Peele, J.; Rhonehouse, D.; Meyers, J.; Thapa, R.; Gibson, D.; Sanghera, J.

    2016-09-01

    We report on the recent progress in the development of cladded single crystal fibers for high power single frequency lasers. Various rare earth doped single crystal YAG fibers with diameters down to 17 μm with length > 1 m have been successfully drawn using a state-of-the-art Laser Heated Pedestal Growth system. Single and double cladding on rare earth doped YAG fibers have been developed using glasses where optical and physical properties were precisely matched to doped YAG core single crystal fiber. The double clad Yb:YAG fiber structures have dimensions analogous to large mode area (LMA) silica fiber. We also report successful fabrications of all crystalline core/clad fibers where thermal and optical properties are superior over glass cladded YAG fibers. Various fabrication methods, optical characterization and gain measurements on these cladded YAG fibers are reported.

  14. Experimental and Theoretical Investigations on Stimulated Brillouin Scattering (SBS) in Multimode Fibers, at 1550 nm Wavelength

    DTIC Science & Technology

    2003-09-01

    determines a beam radius w,, which is equal to the second moment beam radius in the case of a Gaussian beam ( ISO 11146 :1999). The beam propagation...moments, M has to be corrected using the following formula (from ISO 11146 :1999): MA4 0.81 -1+1 (13) The siiilar correction should be done to obtain the...multimode fibers 3 . THEORETICAL MODEL I11o) -1 114 Fiber - " t "I. 5(L) 4/01 L Fig. 2 Schematic used to model the SBS interaction in the fiber The

  15. Demonstration of an ultraviolet stimulated Brillouin scattering pulse compressed hundred picosecond laser in LiB3O5 crystals

    NASA Astrophysics Data System (ADS)

    Bai, Zhenxu; Wang, Yulei; Lu, Zhiwei; Jiang, Li; Yuan, Hang; Liu, Zhaohong

    2017-08-01

    A hundred picosecond ultraviolet (UV) laser is demonstrated with a pulse duration of less than 200 ps and peak power of 0.6 GW. With a hundred picosecond stimulated Brillouin scattering compressed pulse as the fundamental light, the UV output at 355 nm is obtained by extra-cavity sum-frequency-mixing in two LiB3O5 crystals. Maximum UV energy was 100 mJ when the incident energy was 280 mJ, yielding an optical-to-optical efficiency of 35.7%. This result is of interest for the generation of high energy sub-nanosecond UV lasers which finds applications in shock ignition and industrial processing.

  16. 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.

  17. 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.

  18. 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.

  19. Continuously tunable wideband semiconductor fiber-ring laser

    NASA Astrophysics Data System (ADS)

    Mao, Xuefeng; Zhao, Shiwei; Yuan, Suzhen; Wang, Xiaofa; Zheng, Peichao

    2017-08-01

    We demonstrate a wideband tunable semiconductor fiber-ring laser that can be continuously tuned from 1498 nm to 1623 nm. The proposed laser uses a semiconductor optical amplifier (SOA) as a gain medium and a fiber Fabry-Perot tunable filter as a selective wavelength filter. The optimized drive current of the SOA and the output coupling ratio are obtained by experimental research. This laser has a simple configuration, low threshold, flat laser output power and high optical signal-to-noise ratio.

  20. Regulation of a pulsed random fiber laser in the Q-switched regime

    NASA Astrophysics Data System (ADS)

    Zeng, X. P.; Zhang, W. L.; Ma, R.; Yang, Z. J.; Zeng, X.; Dong, X.; Rao, Y. J.

    2016-11-01

    A random fiber laser with regulated Q-switched pulses has been proposed and realized through a half-open cavity, which is formed between a compound fiber-based optic ring resonator (ORR) and a segment of 500 m dispersion compensation fiber (DCF). The compound fiber-based ORR provides frequency filtered feedback, which together with Brillouin scattering of the DCF forms a Q-switched mechanism. As a result, Q-switched pulses are generated randomly. Nevertheless, each Q-switched event typically consists of several ordered sub-pulses with the same pulse interval thanks to resonant interferences of the compound fiber-based ORR. Compared with former reports, the shape and the interval of pulses in each Q-switch event are regulated greatly.

  1. Stimulated Brillouin scattering reduction induced by self-focusing for a single laser speckle interacting with an expanding plasma

    SciTech Connect

    Masson-Laborde, P. E.; Depierreux, S.; Loiseau, P.; Hüller, S.; Pesme, D.; Labaune, Ch.; Bandulet, H.

    2014-03-15

    The origin of the low level of stimulated Brillouin scattering (SBS) observed in laser-plasma experiments carried out with a single laser speckle is investigated by means of three-dimensional simulations and modeling in the limit when the laser beam power P is well above the critical power for ponderomotive self-focusing We find that the order of magnitude of the time averaged reflectivities, together with the temporal and spatial SBS localization observed in our simulations, are correctly reproduced by our modeling. It is observed that, after a short transient stage, SBS reaches a significant level only (i) as long as the incident laser pulse is increasing in amplitude and (ii) in a single self-focused speckle located in the low-density front part of the plasma. In order to describe self-focusing in an inhomogeneous expanding plasma, we have derived a new Lagrangian density describing this process. Using then a variational approach, our model reproduces the position and the peak intensity of the self-focusing hot spot in the front part of the plasma density profile as well as the local density depletion in this hot spot. The knowledge of these parameters then makes it possible to estimate the spatial amplification of SBS as a function of the laser beam power and consequently to explain the experimentally observed SBS reflectivity, considerably reduced with respect to standard theory in the regime of large laser beam power.

  2. 2 cm spatial-resolution and 2 km range Brillouin optical fiber sensor using a transient differential pulse pair.

    PubMed

    Dong, Yongkang; Zhang, Hongying; Chen, Liang; Bao, Xiaoyi

    2012-03-20

    We report a high-spatial-resolution and long-range distributed temperature sensor through optimizing differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA). In DPP-BOTDA, the differential signal suffers from a signal-to-noise ratio (SNR) reduction with respect to the original signals, and for a fixed pulse-width difference the SNR reduction increases with the pulse width. Through reducing the pulse width to a transient regime (near to or less than the phonon lifetime) to decrease the SNR reduction after the differential process, the optimized 8/8.2 ns pulse pair is applied to realize a 2 cm spatial resolution, where a pulse generator with a 150 ps fall-time is used to ensure the effective resolution of DPP-BOTDA. In the experiment, a 2 cm spatial-resolution hot-spot detection with a 2 °C temperature accuracy is demonstrated over a 2 km sensing fiber.

  3. Bend-insensitive distributed sensing in singlemode-multimode-singlemode optical fiber structure by using Brillouin optical time-domain analysis

    NASA Astrophysics Data System (ADS)

    Xu, Pengbai; Zhang, Hongying; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi; Dong, Yongkang

    2015-09-01

    We propose a bend-insensitive distributed Brillouin optical fiber sensing by using a singlemode-multimode-singlemode optical fiber structure for the first time to the best of our knowledge. The sensing fiber is a graded-index multimode fiber (GI-MMF) sandwiched by two standard single-mode fibers (SMFs) with centrally alignment splicing at the interface between GI-MMF and SMF to excite the fundamental mode only in GI-MMF. The sensing system can resist a minimal bend radius of 1.25mm while maintaining the measurement performance, with which the measured coefficient of strain is 421.6MHz/%. We also demonstrate that the higher-order modes exciting in GI-MMF can be easily influenced by bending, so that the fundamental mode exciting is essential for bend-insensitive distributed sensing.

  4. Thulium fiber laser lithotripsy using a muzzle brake fiber tip

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

    2017-02-01

    The Thulium fiber laser (TFL) is being explored as an alternative to Holmium:YAG laser for lithotripsy. TFL beam profile allows coupling of higher power into smaller fibers than multimode Holmium laser beam, without proximal fiber tip degradation. A smaller fiber provides more space in ureteroscope working channel for increased saline irrigation and allows maximum ureteroscope flexion. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback, but increased retropulsion. In this study, a "fiber muzzle brake" was tested for reducing fiber burnback and stone retropulsion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-OD, 360-μm-ID tube with 275-μm thru hole located 250-μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed, ex vivo. Small stones with a mass of 40 +/- 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 +/- 4 s (n=10), without distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers. The muzzle brake fiber tip provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

  5. Advanced fiber lasers and related all-fiber devices

    NASA Astrophysics Data System (ADS)

    Srinivasan, Balaji

    2000-11-01

    Fiber lasers based on rare-earth ions now play an important role in several applications ranging from communications and surgery to spectroscopic sensing because of their efficiency and compactness, and their intrinsic compatibility with single mode communication fibers. As such, there is a strong need to investigate key issues related to the design and fabrication of ``rugged'' state-of-the-art fiber lasers, and in particular to fabricate versatile high-performance fiber lasers based on ``all-fiber'' devices, i.e. using only in-fiber devices. This dissertation addresses some of these needs. One such issue is the polarization property of lasers and amplifiers based on polarization preserving fibers. A dedicated study of the polarization properties of amplifiers and lasers based on rare-earth doped elliptical core fibers has been performed. The results indicate a polarization dependent gain, with a larger gain at the polarization parallel to the major axis of the ellipse. This gain anisotropy is attributed to the differences in the confinement of the two orthogonally polarized fundamental modes of the fiber. Another issue that has been driven by several medical, sensing, and data storage applications is that of efficient laser transitions in the mid-infrared and visible spectral regions. Such lasers are difficult to achieve in conventional fibers based on silica glass hosts due to their relatively large phonon energies. A fluoride based glass host (ZBLAN) with low phonon energy was chosen to enable green and blue laser transitions using upconversion schemes in erbium and thulium respectively, and realize an efficient mid-infrared transition in erbium. Specifically, the following results have been demonstrated: (1)Green (544 nm) fiber laser with the highest combination of power (50 mW) and efficiency (37%) in Er:ZBLAN; (2)Novel Raman fiber laser-pumped 22 mW blue (490 nm) laser in Tm:ZBLAN; (3)Diode-pumped mid-infrared (2.7 μm) laser with 660 mW output in Er

  6. 1940 nm all-fiber Q-switched fiber laser

    NASA Astrophysics Data System (ADS)

    Ahmadi, P.; Estrada, A.; Katta, N.; Lim, E.; McElroy, A.; Milner, T. E.; Mokan, V.; Underwood, M.

    2017-02-01

    We present development of a nanosecond Q-switched Tm3+-doped fiber laser with 16 W average power and 4.4 kW peak power operating at 1940 nm. The laser has a master oscillator power amplifier design, and uses large mode area Tm3+-doped fibers as the gain medium. Special techniques are used to splice Tm3+-doped fibers to minimize splice loss. The laser design is optimized to reduce non-linear effects, including modulation instability. Pulse width broadening due to high gain is observed and studied in detail. Medical surgery is a field of application where this laser may be able to improve clinical practice. The laser together with scanning galvanometer mirrors is used to cut precisely around small footprint vessels in tissue phantoms without leaving any visible residual thermal damage. These experiments provide proof-of-principle that this laser has promising potential in the laser surgery application space.

  7. Investigation on optical and acoustic fields of stimulated Brillouin scattering in As2S3 suspended-core optical fibers

    NASA Astrophysics Data System (ADS)

    Xu, Qiang; Gao, Weiqing; Li, Xue; Ni, Chenquan; Chen, Xiangcai; Chen, Li; Zhang, Wei; Hu, Jigang; Chen, Xiangdong; Yuan, Zijun

    2016-10-01

    The optical and acoustic fields of stimulated Brillouin scattering (SBS) effect in the As2S3 chalcogenide suspended-core microstructured optical fibers (MOFs) are investigated by the finite-element method (FEM). The optical and acoustic fundamental modes at 1550 nm are analyzed with the core diameters of the MOFs varying from 1.0 to 6.0 μm. For each case, the holes of the MOFs are filled with different materials such as trichlormethane (CHCL3), alcohol and water. When the core diameter is 6.0 μm, the maximum peak intensity of the optical fundamental mode is in the case with air holes, while the minimum value is in the case filled with CHCL3. The ratio of difference is 0.66%. The minimum peak intensity of the acoustic fundamental mode is in the case with air holes, while the maximum value is in the case filled with water. The ratio of difference is 0.13%. The same rule occurs in the fiber cores of 4.5, 3.0 and 2.0 μm, where the decreases of 0.97%, 1.48%, 1.94% for optical field and the increases of 0.24%, 0.34%, 0.74% for acoustic field are obtained, respectively. When the core diameter is 1.0 μm, ratios of difference for optical and acoustic fields are much higher than those in the cases of 2.0-6.0 μm, which are 3.55% and 29.13%, respectively. The overlap factors between optical and acoustic fields are calculated, which are changed with the core diameter and the filled material in holes. Our results will be helpful to strengthen or suppress the SBS effect in practical applications.

  8. Fiber-based laser transmitter and laser spectroscopy of the oxygen A-band for remote detection of atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Stephen, Mark Andrew

    The Author reports on the design and construction of an oxygen spectroscopy laser sounding instrument designed to measure atmospheric pressure. This instrument was conceived and designed with a satellite application in mind so we discuss the requirements this places on the instrument and specifically the laser transmitter. We have developed a novel, pulsed, frequency-doubled, fiber-based laser transmitter for use in the instrument. The instrument concept uses the collision broadening of spectroscopic lines of the diatomic oxygen A-band to deduce atmospheric pressure. We report on the spectroscopic and instrument theory. We discuss the development of a high-power, narrow-frequency, tunable, single spatial mode pulsed laser transmitter. The transmitter is a master oscillator power amplifier (MOPA) design. The master oscillator is a fiber coupled DFB laser with external acousto-optic modulation. The amplifier is a diode pumped, erbium-doped fiber. We discuss the non-linear optical effect of stimulated Brillouin scattering (SBS) and how it limits the transmitter performance. We review various methods for overcoming SBS in erbium fiber amplifiers and then demonstrate the performance of a high SBS threshold fiber amplifier. We demonstrate the efficacy of this transmitter by integrating it into a spectroscopic instrument and make atmospheric measurements at a test site at Goddard. We also discuss future improvements.

  9. Watt-level short-length holmium-doped ZBLAN fiber lasers at 1.2  μm.

    PubMed

    Zhu, Xiushan; Zong, Jie; Wiersma, Kort; Norwood, R A; Prasad, Narasimha S; Obland, Michael D; Chavez-Pirson, Arturo; Peyghambarian, N

    2014-03-15

    In-band core-pumped Ho3+-doped ZBLAN fiber lasers at the 1.2 μm region were investigated with different gain fiber lengths. A 2.4 W 1190 nm all-fiber laser with a slope efficiency of 42% was achieved by using a 10 cm long gain fiber pumped at a maximum available 1150 nm pump power of 5.9 W. A 1178 nm all-fiber laser was demonstrated with an output power of 350 mW and a slope efficiency of 6.5%. High Ho3+ doping in ZBLAN is shown to be effective in producing single-frequency fiber lasers and short-length fiber amplifiers immune from stimulated Brillouin scattering.

  10. 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.

  11. 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.

  12. 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.

  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. The truth about laser fiber diameters.

    PubMed

    Kronenberg, Peter; Traxer, Olivier

    2014-12-01

    To measure the various diameters of laser fibers from various manufacturers and compare them with the advertised diameter. Fourteen different unused laser fibers from 6 leading manufacturers with advertised diameters of 200, 270, 272, 273, 365, and 400 μm were measured by light microscopy. The outer diameter (including the fiber coating, cladding, and core), cladding diameter (including the cladding and the fiber core), and core diameter were measured. Industry representatives of the manufacturers were interviewed about the diameter of their fibers. For all fibers, the outer and cladding diameters differed significantly from the advertised diameter (P <.00001). The outer diameter, which is of most practical relevance for urologists, exhibited a median increase of 87.3% (range, 50.7%-116.7%). The outer, cladding, and core diameters of fibers with equivalent advertised diameters differed by up to 180, 100, and 78 μm, respectively. Some 200-μm fibers had larger outer diameters than the 270- to 273-μm fibers. All packaging material and all laser fibers lacked clear and precise fiber diameter information labels. Of 12 representatives interviewed, 8, 3, and 1 considered the advertised diameter to be the outer, the cladding, and the core diameter, respectively. Representatives within the same company frequently gave different answers. This study suggests that, at present, there is a lack of uniformity between laser fiber manufacturers, and most of the information conveyed to urologists regarding laser fiber diameter may be incorrect. Because fibers larger than the advertised laser fibers are known to influence key interventional parameters, this misinformation can have surgical repercussions. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. 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.

  16. 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).

  17. Brillouin backward scattering in the nonlinear interaction of a short-pulse laser with an underdense transversely magnetized plasma with nonextensive distribution

    NASA Astrophysics Data System (ADS)

    Qiu, Hui-Bin; Song, Hai-Ying; Liu, Shi-Bing

    2017-03-01

    Nonlinear Brillouin backward scattering of a linearly polarized short laser pulse propagating through a homogenous nonextensive distributed plasma in the presence of a uniform magnetic field perpendicular to both the direction of propagation and electric vector of the radiation field is investigated theoretically when ponderomotive relativistic and nonlinearity effects up to third order are taken into account. The governing equations for nonlinear wave in the context of nonextensive statistics are given, and the nonextensive coupled equations describing the nonlinear Brillouin backward scattering instability are solved by the Fourier transformation method, and the growth rate of the nonlinear Brillouin backward scattering instability is obtained. The results in the case q → 1 are consistent with those in the framework of the Maxwellian distribution. It is found that the instability growth rate increases on increasing plasma density, radiation field amplitude, and nonextensive parameter, while the instability growth rate shows a decrease due to the presence of external magnetic field.

  18. Advances in drilling with fiber lasers

    NASA Astrophysics Data System (ADS)

    Naeem, Mohammed

    2015-07-01

    High brightness quasi- continuous wave (QCW) and continuous wave (CW) fiber lasers are routinely being used for cutting and welding for a range of industrial applications. However, to date very little work has been carried out or has been reported on laser drilling with these laser sources. This work describes laser drilling ((trepan and percussion) of nickel based superalloys (thermal barrier coated and uncoated) with a high power QCW fiber laser. This presentation will highlight some of the most significant aspect of laser drilling, i.e. SmartPierceTM, deep hole drilling and small hole drilling. These advances in processing also demonstrate the potential for fiber laser processing when an advanced interface between laser and an open architecture controller are used.

  19. 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.

  20. 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.

  1. Dark pulse emission of a fiber laser

    SciTech Connect

    Zhang, H.; Tang, D. Y.; Zhao, L. M.; Wu, X.

    2009-10-15

    We report on the dark pulse emission of an all-normal dispersion erbium-doped fiber laser with a polarizer in cavity. We found experimentally that apart from the bright pulse emission, under appropriate conditions the fiber laser could also emit single or multiple dark pulses. Based on numerical simulations we interpret the dark pulse formation in the laser as a result of dark soliton shaping.

  2. Effect of stimulated Brillouin scattering on the gain saturation of distributed fiber Raman amplifier and its suppression by phase modulation

    NASA Astrophysics Data System (ADS)

    Zhang, Yi-Chi; Chen, Wei; Sun, Shi-Lin; Meng, Zhou

    2015-09-01

    For distributed fiber Raman amplifiers (DFRAs), stimulated Brillouin scattering (SBS) can deplete the pump once occurring and consequently generate gain saturation. On the basis of such a theory, theoretical gain saturation powers in DFRAs with various pump schemes are obtained by calculating SBS thresholds in them, and the experimental results show that they are in excellent agreement with the calculation results. The saturation power of the DFRA with a 300 mW forward pump is as low as 0 dBm, which needs to be enhanced by phase modulation, and the effect is quantitatively studied. A simple model taking both modulation frequency and index into consideration is presented by introducing a correction factor to evaluate the effect of phase modulation on the enhancement of saturation power. Experimentally, it is shown that such a correction factor decreases as the modulation frequency increases and approaches zero when the modulation frequency becomes high enough. In particular, a phase modulation with a modulation frequency of 100 MHz and a modulation index of 1.380 can enhance the saturation power by 4.44 dB, and the correction factor is 0.25 dB, in which the modulation frequency is high enough. Additionally, the factor is 1.767 dB for the modulation frequency of 25 MHz. On this basis, phase modulations with various indexes and a fixed frequency of 25 MHz are adopted to verify the modified model, and the results are positive. To obtain the highest gain saturation power, the model is referable. The research results provide a guide for the design of practical DFRAs. Project supported by the National Natural Science Foundation of China (Grant No. 61177073) and the Major Application Basic Research Project of National University of Defense Technology, China (Grant No. ZDYYJCYJ20140701).

  3. The SMAT fiber laser for industrial applications

    NASA Astrophysics Data System (ADS)

    Ding, Jianwu; Liu, Jinghui; Wei, Xi; Xu, Jun

    2017-02-01

    With the increased adoption of high power fiber laser for various industrial applications, the downtime and the reliability of fiber lasers become more and more important. Here we present our approach toward a more reliable and more intelligent laser source for industrial applications: the SMAT fiber laser with the extensive sensor network and multi-level protection mechanism, the mobile connection and the mobile App, and the Smart Cloud. The proposed framework is the first IoT (Internet of Things) approach integrated in an industrial laser not only prolongs the reliability of an industrial laser but open up enormous potential for value-adding services by gathering and analyzing the Big data from the connected SMAT lasers.

  4. Kagome fiber based industrial laser beam delivery

    NASA Astrophysics Data System (ADS)

    Maurel, M.; Gorse, A.; Beaudou, B.; Lekiefs, Q.; Chafer, M.; Debord, B.; Gérôme, F.; Benabid, F.

    2017-02-01

    We report on a Hollow Core-Photonic Crystal Fiber (HC-PCF) based high power ultra-short pulse laser beam delivery system (GLO-BDS) that combines ease-of-use, high laser-coupling efficiency, robustness and industrial compatible cabling. The GLO-BDS comprises a pre-aligned laser-injection head, a sheath cable protected HC-PCF and a modular fiber-output head. It enables fiber-core gas loading and evacuation in a hermetic fashion. 5 m long GLO-BDS were demonstrated for Yb USP laser, Ti:Sapphire laser and frequency-doubled Yb USP laser. They all exhibit a transmission coefficient larger than 80%, and a laser output profile close to single mode (M2 <1.3).

  5. Kinetic Effects on the Ion Sound Waves Generated by Stimulated Brillouin Scattering of a Spatially Smoothed Laser Beam

    NASA Astrophysics Data System (ADS)

    Riconda, Caterina; Hüller, Stefan; Myatt, Jason; Pesme, Denise

    Stimulated Brillouin Scattering (SBS) can drive ion sound waves to amplitudes such that steepening and particle kinetic effects occur. Such phenomena have been studied recently in spatial volumes corresponding to a single laser speckle, in two [Cohen, B. I. et al. Phys. Plasmas 4, 956 (1997)], and three spatial dimensions [Vu, H. X., Phys. Plasmas 4, 1841 (1997)]. We analyze the results of 2D kinetic simulations modeling the evolution of SBS in the case of a spatially smoothed laser beam interacting with a plasma containing many speckles. For this purpose, we have coupled a 2D particle-in-cell code to a 2D non-paraxial electromagnetic wave solver. The generation of a fast ion population is observed to initially take place in the most intense hot spots, resulting in a decrease of the amplitude of the ion sound wave amplitude generated by SBS in these hot spots. SBS activity is consequently reduced in the most intense laser speckles, so that the overall backscattering SBS reflectivity drops considerably below the values expected from models that do not account for particle kinetics and/or nonlinear hydrodynamics.

  6. Transform-limited pulses generated by an actively Q-switched distributed fiber laser.

    PubMed

    Cuadrado-Laborde, C; Pérez-Millán, P; Andrés, M V; Díez, A; Cruz, J L; Barmenkov, Yu O

    2008-11-15

    A single-mode, transform-limited, actively Q-switched distributed-feedback fiber laser is presented, based on a new in-line acoustic pulse generator. Our technique permits a continuous adjustment of the repetition rate that modulates the Q factor of the cavity. Optical pulses of 800 mW peak power, 32 ns temporal width, and up to 20 kHz repetition rates were obtained. The measured linewidth demonstrates that these pulses are transform limited: 6 MHz for a train of pulses of 10 kHz repetition rate, 80 ns temporal width, and 60 mW peak power. Efficient excitation of spontaneous Brillouin scattering is demonstrated.

  7. Stimulated Brillouin Scattering Microscopic Imaging

    PubMed Central

    Ballmann, Charles W.; Thompson, Jonathan V.; Traverso, Andrew J.; Meng, Zhaokai; Scully, Marlan O.; Yakovlev, Vladislav V.

    2015-01-01

    Two-dimensional stimulated Brillouin scattering microscopy is demonstrated for the first time using low power continuous-wave lasers tunable around 780 nm. Spontaneous Brillouin spectroscopy has much potential for probing viscoelastic properties remotely and non-invasively on a microscopic scale. Nonlinear Brillouin scattering spectroscopy and microscopy may provide a way to tremendously accelerate the data aquisition and improve spatial resolution. This general imaging setup can be easily adapted for specific applications in biology and material science. The low power and optical wavelengths in the water transparency window used in this setup provide a powerful bioimaging technique for probing the mechanical properties of hard and soft tissue. PMID:26691398

  8. 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.

  9. Investigation of Microstructured Optical Fiber in Eight Fiber Laser

    NASA Astrophysics Data System (ADS)

    Bahloul, Faouzi; Ennejah, Tarek; Attia, Rabah

    2012-06-01

    In passively mode locked fiber laser, case of 8FL (Eight Fiber Laser), the management of length, linear and non linear parameters of the cavity plays a paramount role in the generation of stable ultra short pulses with high peak powers. In this work, we propose an 8FL consisted of MOF (Microstructured Optical Fiber). According to the various properties of the MOF, we studied the variation of the pulses peak power and width. We demonstrated that there are optimal parameters of the MOF for which the peak power is maximal and the width is minimal.

  10. Investigation of Microstructured Optical Fiber in Eight Fiber Laser

    NASA Astrophysics Data System (ADS)

    Bahloul, Faouzi; Ennejah, Tarek; Attia, Rabah

    2011-09-01

    In passively mode locked fiber laser, case of 8FL (Eight Fiber Laser), the management of length, linear and non linear parameters of the cavity plays a paramount role in the generation of stable ultra short pulses with high peak powers. In this work, we propose an 8FL consisted of MOF (Microstructured Optical Fiber). According to the various properties of the MOF, we studied the variation of the pulses peak power and width. We demonstrated that there are optimal parameters of the MOF for which the peak power is maximal and the width is minimal.

  11. Fiber laser performance in industrial applications

    NASA Astrophysics Data System (ADS)

    McCulloch, S.; Hassey, A.; Harrison, P.

    2013-02-01

    Fiber lasers are competing with the traditional CO2 Laser, Plasma, Water Jet and Press Punch technology. This paper concentrates on the drivers behind the progress that <=500W CW fiber lasers have made in the thin metal cutting and welding market. Thin metal cutting in this case is defined as below 4mm and the dominant technology has been the Press Punch for higher quality, large volume components and Plasma for lower quality, small quantities. Up until the fiber lasers were commercially available many machine manufacturers were deterred from incorporating lasers due to the technical barriers posed by the lasers available at that time. In particular fiber laser requires no maintenance does not necessitate a beam path to be aligned and kept free of contaminant so have encouraged many traditionally non-laser machine builders to integrate fiber sources into a variety of applications and push the performance envelope. All of the components to build a fibre laser cutting or welding system are now available "off-the shelf" which is even allowing end users to design and build their own systems directly in production environments.

  12. Fiber Bragg filters For laser- and multicore fibers

    NASA Astrophysics Data System (ADS)

    Becker, Martin; Elsmann, Tino; Lorenz, Adrian; Rothhardt, Manfred

    2017-05-01

    Fiber Bragg gratings (FBGs) have widespread applications in security, information, structural health monitoring, and biophotonics. In telecom applications, FBG inscription has reached a high level of maturity, but remains mainly limited to germanium doped photosensitive single mode fibers. Special applications, like filtering in light harvesting fibers or resonator mirrors for fiber lasers have to deal with special aspects which make the design and realization of FBGs a challenging task. One aspect is the extended wavelength range of these applications. Another aspect is the increasing demand to inscribe fiber Bragg gratings in non-photosensitive germanium-free fibers. Therefore, novel concepts of photosensitivity are proposed. Finally, to increase the amount of captured light the size of the fiber core and the numerical aperture have also to be increased. This goes along with multimode operation and prevents good filtering properties of Bragg gratings.

  13. Simulation and measurement of threshold pump powers for the stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) in ytterbium-doped double-clad CW fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Abdollahi, M.; Bagheri Harouni, M.; Hekmat, M. J.; Fakhari, M.; Shahriari, N.; Kanani, M.; Normohamadi, H.

    2016-11-01

    By considering propagation equations of Stokes-waves for different orders of the stimulated Brillouin scattering (SBS) and the stimulated Raman scattering (SRS) together with propagation-rate equations of Ytterbium-doped double-clad fiber amplifiers, we numerically analyze steady-state characteristics of these amplifiers such as Amplified Spontaneous Emission (ASE) and threshold pump power and parameters which have influence over it such as pumping configuration, pumping wavelength, input signal wavelength, input signal power, input signal bandwidth and amplifier geometry. Also in an experimental setup threshold pump powers under both forward and backward pumping configurations are measured. Our results are of prime importance for applications such as nonlinear frequency generation.

  14. Progress in Cherenkov femtosecond fiber lasers.

    PubMed

    Liu, Xiaomin; Svane, Ask S; Lægsgaard, Jesper; Tu, Haohua; Boppart, Stephen A; Turchinovich, Dmitry

    2016-01-20

    We review the recent developments in the field of ultrafast Cherenkov fiber lasers. Two essential properties of such laser systems - broad wavelength tunability and high efficiency of Cherenkov radiation wavelength conversion are discussed. The exceptional performance of the Cherenkov fiber laser systems are highlighted - dependent on the realization scheme, the Cherenkov lasers can generate the femtosecond output tunable across the entire visible and even the UV range, and for certain designs more than 40 % conversion efficiency from the pump to Cherenkov signal can be achieved. The femtosecond Cherenkov laser with all-fiber architecture is presented and discussed. Operating in the visible range, it delivers 100-200 fs wavelength-tunable pulses with multimilliwatt output power and exceptionally low noise figure an order of magnitude lower than the traditional wavelength tunable supercontinuum-based femtosecond sources. The applications for Cherenkov laser systems in practical biophotonics and biomedical applications, such as bio-imaging and microscopy, are discussed.

  15. Progress in Cherenkov femtosecond fiber lasers

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomin; Svane, Ask S.; Lægsgaard, Jesper; Tu, Haohua; Boppart, Stephen A.; Turchinovich, Dmitry

    2016-01-01

    We review the recent developments in the field of ultrafast Cherenkov fiber lasers. Two essential properties of such laser systems—broad wavelength tunability and high efficiency of Cherenkov radiation wavelength conversion are discussed. The exceptional performance of the Cherenkov fiber laser systems are highlighted—dependent on the realization scheme, the Cherenkov lasers can generate the femtosecond output tunable across the entire visible and even the UV range, and for certain designs more than 40% conversion efficiency from the pump to Cherenkov signal can be achieved. The femtosecond Cherenkov laser with all-fiber architecture is presented and discussed. Operating in the visible range, it delivers 100-200 fs wavelength-tunable pulses with multimilliwatt output power and exceptionally low noise figure an order of magnitude lower than the traditional wavelength tunable supercontinuum-based femtosecond sources. The applications for Cherenkov laser systems in practical biophotonics and biomedical applications, such as bio-imaging and microscopy, are discussed.

  16. Progress in Cherenkov femtosecond fiber lasers

    PubMed Central

    Liu, Xiaomin; Svane, Ask S.; Lægsgaard, Jesper; Tu, Haohua; Boppart, Stephen A.; Turchinovich, Dmitry

    2016-01-01

    We review the recent developments in the field of ultrafast Cherenkov fiber lasers. Two essential properties of such laser systems – broad wavelength tunability and high efficiency of Cherenkov radiation wavelength conversion are discussed. The exceptional performance of the Cherenkov fiber laser systems are highlighted - dependent on the realization scheme, the Cherenkov lasers can generate the femtosecond output tunable across the entire visible and even the UV range, and for certain designs more than 40 % conversion efficiency from the pump to Cherenkov signal can be achieved. The femtosecond Cherenkov laser with all-fiber architecture is presented and discussed. Operating in the visible range, it delivers 100–200 fs wavelength-tunable pulses with multimilliwatt output power and exceptionally low noise figure an order of magnitude lower than the traditional wavelength tunable supercontinuum-based femtosecond sources. The applications for Cherenkov laser systems in practical biophotonics and biomedical applications, such as bio-imaging and microscopy, are discussed. PMID:27110037

  17. Fiber laser for high speed laser transfer printing

    NASA Astrophysics Data System (ADS)

    Petkovšek, Rok; Novak, Vid; Agrež, Vid

    2017-01-01

    High speed industrial laser transfer printing requires high power lasers that can deliver pulses on demand and having arbitrary pulse duration in range of few nanoseconds to milliseconds or more. A special kind of MOPA fiber laser is presented using wavelength multiplexing to achieve pulses on demand with minimal transients. The system is further tested in printing application.

  18. Multiplexed fiber-ring laser sensors for ultrasonic detection.

    PubMed

    Liu, Tongqing; Hu, Lingling; Han, Ming

    2013-12-16

    We propose and demonstrate a multiplexing method for ultrasonic sensors based on fiber Bragg gratings (FBGs) that are included inside the laser cavity of a fiber-ring laser. The multiplexing is achieved using add-drop filters to route the light signals, according to their wavelengths, into different optical paths, each of which contains a separate span of erbium-doped fiber (EDF) as the gain medium. Because a specific span of EDF only addresses a single wavelength channel, mode completion is avoided and the FBG ultrasonic sensors can be simultaneously demodulated. The proposed method is experimentally demonstrated using a two-channel system with two sensing FBGs in a single span of fiber.

  19. Flexible pulse-controlled fiber laser

    PubMed Central

    Liu, Xueming; Cui, Yudong

    2015-01-01

    Controlled flexible pulses have widespread applications in the fields of fiber telecommunication, optical sensing, metrology, and microscopy. Here, we report a compact pulse-controlled all-fiber laser by exploiting an intracavity fiber Bragg grating (FBG) system as a flexible filter. The width and wavelength of pulses can be tuned independently by vertically and horizontally translating a cantilever beam, respectively. The pulse width of the laser can be tuned flexibly and accurately from ~7 to ~150 ps by controlling the bandwidth of FBG. The wavelength of pulse can be tuned precisely with the range of >20 nm. The flexible laser is precisely controlled and insensitive to environmental perturbations. This fiber-based laser is a simple, stable, and low-cost source for various applications where the width-tunable and/or wavelength-tunable pulses are necessary. PMID:25801546

  20. Flexible pulse-controlled fiber laser

    NASA Astrophysics Data System (ADS)

    Liu, Xueming; Cui, Yudong

    2015-03-01

    Controlled flexible pulses have widespread applications in the fields of fiber telecommunication, optical sensing, metrology, and microscopy. Here, we report a compact pulse-controlled all-fiber laser by exploiting an intracavity fiber Bragg grating (FBG) system as a flexible filter. The width and wavelength of pulses can be tuned independently by vertically and horizontally translating a cantilever beam, respectively. The pulse width of the laser can be tuned flexibly and accurately from ~7 to ~150 ps by controlling the bandwidth of FBG. The wavelength of pulse can be tuned precisely with the range of >20 nm. The flexible laser is precisely controlled and insensitive to environmental perturbations. This fiber-based laser is a simple, stable, and low-cost source for various applications where the width-tunable and/or wavelength-tunable pulses are necessary.

  1. Two-dimensional particle-in-cell simulations of plasma cavitation and bursty Brillouin backscattering for nonrelativistic laser intensities

    SciTech Connect

    Riconda, C.; Weber, S.; Tikhonchuk, V. T.; Adam, J.-C.; Heron, A.

    2006-08-15

    Two-dimensional particle-in-cell simulations of laser-plasma interaction using a plane-wave geometry show strong bursty stimulated Brillouin backscattering, rapid filamentation, and subsequent plasma cavitation. It is shown that the cavitation is not induced by self-focusing. The electromagnetic fields below the plasma frequency that are excited are related to transient soliton-like structures. At the origin of these solitons is a three-wave decay process exciting new modes in the plasma. The cavitation is responsible for a strong local reduction of the reflectivity and goes along with an efficient but transient heating of the electrons. Once heating ceases, transmission starts to increase. Local as well as global average reflectivities attain a very low value due to strong plasma density variations brought about by the cavitation process. On the one hand, the simulations confirm the existence of a new mechanism of cavity and soliton formation in nonrelativistic laser-plasma interaction in two dimensions, which was shown to exist in one-dimensional simulations [S. Weber, C. Riconda, and V. T. Tikhonchuk, Phys. Rev. Lett. 94, 055005 (2005)]. On the other hand, new aspects are introduced inherently related to the additional degree of freedom.

  2. 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.

  3. An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

    SciTech Connect

    Bradley, Keith Stanley

    1993-02-11

    Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory`s assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this series of experiments was the development of a new instrument, the Multiple Angle Time Resolving Spectrometer (MATRS). MATRS has the unique capability of both spectrally and temporally resolving absolute levels of scattered light at many angles simultaneously, and is the first of its kind used in laser-plasma experiments. A detailed comparison of the theoretical predictions and the experimental observations is made.

  4. Pump-limited, 203 W, single-frequency monolithic fiber amplifier based on laser gain competition.

    PubMed

    Zeringue, Clint; Vergien, Christopher; Dajani, Iyad

    2011-03-01

    We present high power results of a Yb-doped fiber amplifier seeded with a combination of broad and single-frequency laser signals. This two-tone concept was used in conjunction with externally applied or intrinsically formed thermal gradients to demonstrate combined stimulated Brillouin scattering suppression in a copumped monolithic, polarization-maintaining (PM) fiber. Depending on the input parameters and the thermal gradient, the output power of the single-frequency signal ranged from 80 to 203 W with slope efficiencies from 70% to 80%. The 203 W amplifier was pump limited and is, to the best of our knowledge, the highest reported in the literature for monolithic, PM single-frequency fiber amplifiers.

  5. 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.

  6. Multi-dimensional dynamics of stimulated Brillouin scattering in a laser speckle: Ion acoustic wave bowing, breakup, and laser-seeded two-ion-wave decay

    DOE PAGES

    Albright, B. J.; Yin, L.; Bowers, K. J.; ...

    2016-03-04

    Two- and three-dimensional particle-in-cell simulations of stimulated Brillouin scattering(SBS) in laser speckle geometry have been analyzed to evaluate the relative importance of competing nonlinear processes in the evolution and saturation of SBS. It is found that ion-trapping-induced wavefront bowing and breakup of ion acoustic waves(IAW) and the associated side-loss of trapped ions dominate electron-trapping-induced IAW wavefront bowing and breakup, as well as the two-ion-wave decay instability over a range of ZTe/Ti conditions and incident laser intensities. In the simulations, the latter instability does not govern the nonlinear saturation of SBS; however, evidence of two-ion-wave decay is seen, appearing as amore » modulation of the ion acoustic wavefronts. This modulation is periodic in the laser polarization plane, anti-symmetric across the speckle axis, and of a wavenumber matching that of the incident laser pulse. Furthermore, a simple analytic model is provided for how spatial “imprinting” from a high frequency inhomogeneity (in this case, the density modulation from the laser) in an unstable system with continuum eigenmodes can selectively amplify modes with wavenumbers that match that of the inhomogeneity.« less

  7. Frequency Doubling In Raman Fiber Lasers

    DTIC Science & Technology

    2009-02-01

    into the fiber . Recenlly 1 0 kW CW YFL system appears on the market (ILR-100(){] by IPG Photonics Corp., USA). In splle of the outstanding advances in...germanosilicate (GeO2/SiO2) ones is 3 times larger Stokes shift, therefore is possible to convert powerful Yb-doped fiber laser (YDFL) pump radiation at...one used in tunable RFL configuration [8]. The YDFL is pumped by 3 laser diodes (LDs) and delivers up to 13.8 W at ~1.11 µm via output fiber Bragg

  8. Comparison of fiber lasers based on distributed side-coupled cladding-pumped fibers and double-cladding fibers.

    PubMed

    Huang, Zhihe; Cao, Jianqiu; Guo, Shaofeng; Chen, Jinbao; Xu, Xiaojun

    2014-04-01

    We compare both analytically and numerically the distributed side-coupled cladding-pumped (DSCCP) fiber lasers and double cladding fiber (DCF) lasers. We show that, through optimization of the coupling and absorbing coefficients, the optical-to-optical efficiency of DSCCP fiber lasers can be made as high as that of DCF lasers. At the same time, DSCCP fiber lasers are better than the DCF lasers in terms of thermal management.

  9. 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.

  10. 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.

  11. Laser fiber optics ordnance initiation system

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1976-01-01

    Recent progress on system development in the laser initiation of explosive devices is summarized. The topics included are: development of compact free-running mode and Q-switched lasers, development of low-loss fiber optic bundles and connectors, study of nuclear radiation effects on the system, characterization of laser initiation sensitivities of insensitive high explosives, and the design methods used to achieve attractive system weight and cost savings. Direction for future work is discussed.

  12. Laser fiber optics ordnance initiation system

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1976-01-01

    Recent progress on system development in the laser initiation of explosive devices is summarized. The topics included are: development of compact free-running mode and Q-switched lasers, development of low-loss fiber optic bundles and connectors, study of nuclear radiation effects on the system, characterization of laser initiation sensitivities of insensitive high explosives, and the design methods used to achieve attractive system weight and cost savings. Direction for future work is discussed.

  13. Photonic crystal fiber amplifiers for high power ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Alkeskjold, Thomas T.; Laurila, Marko; Weirich, Johannes; Johansen, Mette M.; Olausson, Christina B.; Lumholt, Ole; Noordegraaf, Danny; Maack, Martin D.; Jakobsen, Christian

    2013-12-01

    In recent years, ultrafast laser systems using large-mode-area fiber amplifiers delivering several hundreds of watts of average power has attracted significant academic and industrial interest. These amplifiers can generate hundreds of kilowatts to megawatts of peak power using direct amplification and multi-gigawatts of peak power using pulse stretching techniques. These amplifiers are enabled by advancements in Photonic Crystal Fiber (PCF) design and manufacturing technology. In this paper, we will give a short overview of state-of-the-art PCF amplifiers and describe the performance in ultrafast ps laser systems.

  14. Evidence of plasma fluctuations and their effect on the growth of stimulated Brillouin and stimulated Raman scattering in laser plasmas

    SciTech Connect

    Montgomery, D.S.; Afeyan, B.B.; Cobble, J.A.; Fernandez, J.C.; Wilke, M.D.; Glenzer, S.H.; Kirkwood, R.K.; MacGowan, B.J.; Moody, J.D.; Lindman, E.L.; Munro, D.H.; Wilde, B.H.; Rose, H.A.; Dubois, D.F.; Bezzerides, B.; Vu, H.X.

    1998-05-01

    The reflectivity levels of stimulated Brillouin scattering (SBS) in recent large scale length laser plasma experiments is much lower than expected for conditions where the convective gain exponent is expected to be large [J. C. Fern{acute a}ndez {ital et al.}, Phys. Plasmas {bold 4}, 1849 (1997)]. Long-wavelength velocity fluctuations caused during the plasma formation process, or by parametric instabilities themselves, have been proposed as a mechanism to detune SBS in these experiments and reduce its gain [W. L. Kruer {ital et al.}, Phys. Plasmas {bold 3}, 382 (1996); H. A. Rose, Phys. Plasmas {bold 4}, 437 (1997)]. Evidence of large-velocity fluctuation levels is found in the time-resolved SBS spectra from these experiments, and correlates with observed changes in the reflectivity of both SBS and stimulated Raman scattering (SRS). Evidence of fluctuations that increase with increasing plasma density is presented, and their effect on the growth of parametric instabilities is discussed. {copyright} {ital 1998 American Institute of Physics.}

  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. Brillouin optical time-domain analysis sensor assisted by Brillouin distributed amplification of pump pulses.

    PubMed

    Urricelqui, Javier; Sagues, Mikel; Loayssa, Alayn

    2015-11-16

    We demonstrate the extension of the measurement range of Brillouin optical time-domain analysis (BOTDA) sensors using a distributed Brillouin amplifier (DBA). The technique is based on injecting a DBA pump wave in the fiber to generate an additional Brillouin interaction that amplifies the BOTDA pump pulses and compensates optical fiber attenuation. This amplification does not introduce any significant noise to the BOTDA's probe wave due to the inherent directionality of the Brillouin gain. Additionally, we deploy a differential pulse-width pair measurement method to avoid measurement errors due to the interplay between the self-phase modulation effect and the changes in the temporal shape of the pulses induced by the transient behavior of Brillouin gain. Experimental proof-of-concept results in a 50-km fiber link demonstrate full compensation of the fiber's attenuation with no penalty on the signal-to-noise ratio of the detected signal.

  17. 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

  18. Synthesis of Brillouin frequency shift profiles to compensate non-local effects and Brillouin induced noise in BOTDA sensors.

    PubMed

    Urricelqui, Javier; Sagues, Mikel; Loayssa, Alayn

    2014-07-28

    We present a novel technique for Brillouin optical time domain analysis (BOTDA) sensors that simultaneously compensates non-local effects and reduces Brillouin noise. The technique relies on the wavelength modulation of the optical source to modify the Brillouin interaction between probe and pump waves during their propagation. The resulting Brillouin distribution mimics the wavelength modulation, creating a virtual Brillouin frequency shift profile along the sensing fiber. The fundamentals of the technique are first described theoretically and using numerical simulations. Then, proof-of-concept experiments demonstrate the capabilities of the system to reduce large variations of the pump power resulting from the interaction with high probe powers and to decrease the Brillouin induced noise enhancing the signal to noise ratio (SNR) of the system. Furthermore, we show, for the first time to our knowledge, measurements of the Brillouin distribution using an injected optical power higher than the Brillouin threshold of the fiber.

  19. Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

    PubMed

    Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

    2016-04-18

    The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

  20. 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).

  1. 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).

  2. 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.

  3. Fiber based mode locked fiber laser using Kerr effect

    NASA Astrophysics Data System (ADS)

    Wang, Long

    This dissertation reports on the research to design and build a pulsed fiber laser with the Er doped fiber based on a new mode locking technique. The numerical simulations begin by launching an optical wave in a fiber which will be amplified during propagation. The device to mode-lock the waves is outside the fiber, but connecting to fibers at both ends; it is a nonlinear optical material that can reshape the beam as it propagates using a nonlinear change of the refractive index, which is called a Kerr effect. The device is made with a nonlinear material sandwiched between two fiber ends; it takes an optical field from one end of the fiber and propagates it to the other fiber end. In between the two ends, a nonlinear medium will be used to balance the diffraction through Kerr effect (which can lead to Self-focusing of the optical beam). With the second fiber end working as a soft aperture, the combination of the self-focusing effect through the nonlinear medium and the aperture will act as an intensity dependent coupling loss; this effect is referred to as a fast saturable absorber which means that higher intensity corresponds to higher coupling efficiency and thus the cavity modes will be gradually phase locked together to form pulses. The saturable absorber action is calculated using different nonlinear mediums (CS2, As2S2 and As 40Se60) and the fibers used are assumed to be of the same size. Whole cavity simulation is then conducted using the proposed SA design and the pulse energy produced from the laser cavity is generally below 1 nJ. In those simulations the pulse peak power is weak and the saturable absorber action is not strong. Experiments are designed to test the mode locking idea with the chalcogenide glass plate (As40Se60). Firstly, a mode locked laser is constructed from a ring fiber laser cavity with an Er doped fiber as the gain fiber. Three modes from this cavity are routinely generated. Two modes have pulse durations of 220 fs and 160 fs with

  4. Polarimetric fiber laser sensor for hydrostatic pressure.

    PubMed

    Bohnert, Klaus; Frank, Andreas; Rochat, Etienne; Haroud, Karim; Brändle, Hubert

    2004-01-01

    A polarimetric Fabry-Perot fiber laser sensor for fluid pressure up to 100 MPa is investigated. The fluid acts on one of two elliptical-core fiber sections in the laser cavity, producing a shift in the differential phase of the two orthogonal polarization modes and thus a variation in the beat frequencies of the corresponding longitudinal laser modes. The second fiber section, with a 90 degrees offset in the core orientation, compensates for temperature-induced phase shifts. The dispersion in the birefringent fiber Bragg grating reflectors is employed to remove the near degeneracy of the polarization mode beat frequencies of a given order and to improve substantially the resolution of the sensor to a few parts in 10(6) of the free spectral range. Further investigations address the effect of the fluid on the integrity of the fiber, the influence of various fiber coatings on the sensor response, and the intrinsic stability of erbium-doped and undoped sensing fibers under fluid pressure.

  5. 2μm fiber laser sources and their applications

    NASA Astrophysics Data System (ADS)

    Geng, Jihong; Wang, Qing; Jiang, Shibin

    2011-09-01

    Mid-infrared fiber laser sources have attracted a lot of interest in space and defense applications. We review our latest developments of various fiber laser sources operating near 2μm based on Tm3+ and Ho3+ ions, which include singlefrequency CW laser sources, Q-switched laser sources, mode-locked laser sources. Potential applications of these fiber laser sources are also briefly discussed.

  6. All fiber thulium-doped fiber laser pumped Q-switched Ho:YAP laser

    NASA Astrophysics Data System (ADS)

    Yu, Ting; Ye, Xisheng; Yang, Zhongguo; Chen, Xiaolong; Xia, Wenbin; Zhang, Jiayang; Zhang, Wei; Chen, Jianyu; Si, Jiliang; Chen, Weibiao

    2017-05-01

    The high power infrared 2μm lasers have been extensively investigated for a number of commercial, scientific and engineering applications, such as remote chemical sensing, medical diagnostics, eye-safe laser radar, and environmental monitoring. Furthermore, high-power 2μm lasers are effective pump sources of optical parametrical oscillators and optical parametrical amplifications to generate mid-infrared 3-5μm laser. In recent years, Ho:YAlO3(Ho:YAP) crystal has drawn great attention as a promising efficient laser material for its long emission wavelength at 2118nm. An acoustic-optical Q-switched Ho:YAP laser pumped by an all fiber thulium-doped fiber laser is demonstrated. The all fiber thulium-doped fiber laser can emit 80W output power, and the output laser wavelength is 1915nm. By using this 1915nm laser to end pump the AO Q-switched Ho:YAP laser system, 2118nm laser with 30W average power and 45ns pulse width at 20kHz repetition rates was obtained.

  7. High-efficiency fiber laser at 1018 nm using Yb-doped phosphosilicate fiber.

    PubMed

    Wang, Jianhua; Chen, Gui; Zhang, Lei; Hu, Jinmeng; Li, Jinyan; He, Bing; Chen, Jinbao; Gu, Xijia; Zhou, Jun; Feng, Yan

    2012-10-10

    A high-efficiency fiber laser at 1018 nm using homemade Yb-doped phosphosilicate fiber is demonstrated. The fiber shows blueshifted emission spectrum compared to Yb-doped aluminosilicate fiber, and is considered favorable for the short wavelength Yb-doped fiber laser. With a 7 m gain fiber, up to 22.8 W output at 1018 nm is achieved with an optical efficiency of 53%. The amplified spontaneous emission at 1030 nm is suppressed to 50 dB below the 1018 nm laser. This work shows that highly-efficient fiber laser at 1018 nm can be obtained with Yb-doped phosphosilicate fiber.

  8. 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.

  9. 100 W all fiber picosecond MOPA laser.

    PubMed

    Chen, Sheng-Ping; Chen, Hong-Wei; Hou, Jing; Liu, Ze-Jin

    2009-12-21

    A high power picosecond laser is constructed in an all fiber master oscillator power amplifier (MOPA) configuration. The seed source is an ytterbium-doped single mode fiber laser passively mode-locked by a semiconductor saturable absorber mirror (SESAM). It produces 20 mW average power with 13 ps pulse width and 59.8 MHz repetition rate. A direct amplification of this seed source encounters obvious nonlinear effects hence serious spectral broadening at only ten watt power level. To avoid these nonlinear effects, we octupled the repetition rate to about 478 MHz though a self-made all fiber device before amplification. The ultimate output laser exhibits an average power of 96 W, a pulse width of 16 ps, a beam quality M2 of less than 1.5, and an optical conversion efficiency of 61.5%.

  10. Advanced specialty fiber designs for high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Gu, Guancheng

    The output power of fiber lasers has increased rapidly over the last decade. There are two major limiting factors, namely nonlinear effects and transverse mode instability, prohibiting the power scaling capability of fiber lasers. The nonlinear effects, originating from high optical intensity, primarily limit the peak power scaling. The mode instability, on the other hand, arises from quantum-defect driven heating, causing undesired mode coupling once the power exceeds the threshold and degradation of beam quality. The mode instability has now become the bottleneck for average output power scaling of fiber lasers. Mode area scaling is the most effective way to mitigate nonlinear effects. However, the use of large mode area may increase the tendency to support multiple modes in the core, resulting in lower mode instability threshold. Therefore, it is critical to maintain single mode operation in a large mode area fiber. Sufficient higher order mode suppression can lead to effective single-transverse-mode propagation. In this dissertation, we explore the feasibility of using specialty fiber to construct high power fiber lasers with robust single-mode output. The first type of fiber discussed is the resonantly-enhanced leakage channel fiber. Coherent reflection at the fiber outer boundary can lead to additional confinement especially for highly leaky HOM, leading to lower HOM losses than what are predicted by conventional finite element mothod mode solver considering infinite cladding. In this work, we conducted careful measurements of HOM losses in two leakage channel fibers (LCF) with circular and rounded hexagonal boundary shapes respectively. Impact on HOM losses from coiling, fiber boundary shapes and coating indexes were studied in comparison to simulations. This work demonstrates the limit of the simulation method commonly used in the large-mode-area fiber designs and the need for an improved approach. More importantly, this work also demonstrates that a

  11. 142.2km BOTDA based on ultra-long fiber laser with a ring cavity

    NASA Astrophysics Data System (ADS)

    Jia, Xin-Hong; Rao, Yunjiang; Wang, Zi-Nan; Zhang, Wei-Li; Yuan, Cheng-Xu; Yan, Xiao-Dong; Li, Jin; Wu, Han; Zhu, Ye-Yu; Peng, Fei

    2013-09-01

    A novel distributed Raman amplification (DRA) scheme based on ultra-long fiber laser (UL-FL) pumping with a ring cavity rather than a linear cavity is proposed and demonstrated, for the first time. As a typical application of the proposed configuration, ultra-long-distance distributed sensing with Brillouin optical time-domain analysis (BOTDA) over 142.2km fiber with 5m spatial resolution and +/- 1.5° temperature uncertainty is achieved, without any repeater, for the first time. The key point for the significant performance improvement is the system could offer both of uniform gain distribution and considerably suppressed pump-probe relative intensity noise (RIN) transfer, by optimized design of system structure and parameters.

  12. 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.

  13. Fiber Bragg grating inscription with UV femtosecond exposure and two beam interference for fiber laser applications

    NASA Astrophysics Data System (ADS)

    Becker, Martin; Brückner, Sven; Lindner, Eric; Rothhardt, Manfred; Unger, Sonja; Kobelke, Jens; Schuster, Kay; Bartelt, Hartmut

    2010-06-01

    Fiber Bragg grating based fiber lasers are promising for stable all fiber laser solutions. Standard methods for fiber Bragg gratings in fiber lasers apply germanium doped passive fibers which are connected to the amplifier section of the fiber laser with a splice. The connection is usually recoated using a low-index polymer coating to maintain guidance properties for the pump light. At high pump powers the spliced connections are affected by absorbed pump light and are prone to thermal degradation. Fiber Bragg gratings made with femtosecond laser exposure allow the direct inscription of resonator mirrors for fiber lasers into the amplifying section of the fiber laser. Such a technology has a number of advantages. The number of splices in the laser cavity is reduced. Fiber Bragg grating inscription does not relay on hydrogenation to increase the photosensitivity of the fiber. This is of special interest since hydrogen loading in large mode area fibers is a time consuming procedure due to the diffusion time of hydrogen in silica glass. Finally, one gets direct access to fiber Bragg gratings in air-clad fibers. In this paper we use a two beam interferometric inscription setup in combination with an frequency tripled femtosecond laser for grating inscription. It allows to write fiber Bragg gratings in rare earth doped fibers with a reflection wavelength span that covers the Ytterbium amplification band. Reflections with values higher than 90% have been realized.

  14. Robust synchronization in fiber laser arrays

    NASA Astrophysics Data System (ADS)

    Peleš, Slaven; Rogers, Jeffrey L.; Wiesenfeld, Kurt

    2006-02-01

    Synchronization of coupled fiber lasers has been reported in recent experiments [Bruesselbach , Opt. Lett. 30, 1339 (2005); Minden , Proc. SPIE 5335, 89 (2004)]. While these results may lead to dramatic advances in laser technology, the mechanism by which these lasers synchronize is not understood. We analyze a recently proposed [Rogers , IEEE J. Quantum Electron. 41, 767 (2005)] iterated map model of fiber laser arrays to explore this phenomenon. In particular, we look at synchronous solutions of the maps when the gain fields are constant. Determining the stability of these solutions is analytically tractable for a number of different coupling schemes. We find that in the most symmetric physical configurations the most symmetric solution is either unstable or stable over insufficient parameter range to be practical. In contrast, a lower symmetry configuration yields surprisingly robust coherence. This coherence persists beyond the pumping threshold for which the gain fields become time dependent.

  15. Robust synchronization in fiber laser arrays.

    PubMed

    Peles, Slaven; Rogers, Jeffrey L; Wiesenfeld, Kurt

    2006-02-01

    Synchronization of coupled fiber lasers has been reported in recent experiments [Bruesselbach, Opt. Lett. 30, 1339 (2005); Minden, Proc. SPIE 5335, 89 (2004)]. While these results may lead to dramatic advances in laser technology, the mechanism by which these lasers synchronize is not understood. We analyze a recently proposed [Rogers, IEEE J. Quantum Electron. 41, 767 (2005)] iterated map model of fiber laser arrays to explore this phenomenon. In particular, we look at synchronous solutions of the maps when the gain fields are constant. Determining the stability of these solutions is analytically tractable for a number of different coupling schemes. We find that in the most symmetric physical configurations the most symmetric solution is either unstable or stable over insufficient parameter range to be practical. In contrast, a lower symmetry configuration yields surprisingly robust coherence. This coherence persists beyond the pumping threshold for which the gain fields become time dependent.

  16. CO2-Laser Cutting Fiber Reinforced Polymers

    NASA Astrophysics Data System (ADS)

    Mueller, R.; Nuss, Rudolf; Geiger, Manfred

    1989-10-01

    Guided by experimental investigations laser cutting of glass fiber reinforced reactive injection moulded (RRIM)-polyurethanes which are used e.g. in car industry for bumpers, spoilers, and further components is described. A Comparison with other cutting techniques as there are water jet cutting, milling, punching, sawing, cutting with conventional knife and with ultrasonic excited knife is given. Parameters which mainly influence cutting results e.g. laser power, cutting speed, gas nature and pressure will be discussed. The problematic nature in characterising micro and macro geometry of laser cut edges of fiber reinforced plastic (FRP) is explained. The topography of cut edges is described and several characteristic values are introduced to specify the obtained working quality. The surface roughness of laser cut edges is measured by both, an optical and a mechanical sensor and their reliabilities are compared.

  17. 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.

  18. 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.

  19. Nonlinear processes associated with the amplification of MHz-linewidth laser pulses in single-mode Tm:fiber

    NASA Astrophysics Data System (ADS)

    Sincore, Alex; Bodnar, Nathan; Bradford, Joshua; Abdulfattah, Ali; Shah, Lawrence; Richardson, Martin C.

    2017-03-01

    This work studies the accumulated nonlinearities when amplifying a narrow linewidth 2053 nm seed in a single mode Tm:fiber amplifier. A <2 MHz linewidth CW diode seed is externally modulated using a fiberized acousto-optic modulator. This enables independent control of repetition rate and pulse duration (>30 ns). The pulses are subsequently amplified and the repetition rate is further reduced using a second acousto-optic modulator. It is well known that spectral degradation occurs in such fibers for peak powers over 100's of watts due to self-phase modulation, four-wave mixing, and stimulated Raman scattering. In addition to enabling a thorough test bed to study such spectral broadening, this system will also enable the investigation of stimulated Brillouin scattering thresholds in the same system. This detailed study of the nonlinearities encountered in 2 μm fiber amplifiers is important in a range of applications from telecommunications to the amplification of ultrashort laser pulses.

  20. Stable and uniform dual-wavelength erbium-doped fiber laser based on fiber Bragg gratings and photonic crystal fiber.

    PubMed

    Liu, Xueming; Yang, Xiufeng; Lu, Fuyun; Ng, Junhong; Zhou, Xiaoqun; Lu, Chao

    2005-01-10

    Based on the fiber Bragg gratings (FBGs) and high nonlinear photonic crystal fiber (HN-PCF), a novel dual-wavelength erbium-doped fiber (EDF) laser is proposed and demonstrated. The experimental results show that, owing to the contributions of two degenerate four-wave mixings in the HN-PCF, the proposed fiber laser is great stable and two output signals are uniform at room temperature. With adjustment of the attenuator, our fiber laser can selectively realize one wavelength lasing.

  1. Hybrid Fiber-Bulk Pulsed Erbium Laser

    DTIC Science & Technology

    2007-11-02

    Judd - Ofelt analysis (for radiative lifetimes) and the gap law (for non-radiative transitions by phonon emission). In both calculations, we have...3.6 Prospects for further power scaling 4.0 Fiber laser pumped Er:YAG laser 4.1 Introduction 4.2 Er:YAG laser design 4.3 Effect of Er3 ...procedure, so it is extremely important to identify the main factors affecting the overall efficiency. Er3 + and Yb3+ ion concentrations and background

  2. Fiber ring laser with a feedback mirror.

    PubMed

    Abitan, H; Bohr, H; Pedersen, C F

    2005-12-20

    We describe the spectral and power features of a ytterbium-doped double-clad photonic crystal fiber laser that is operated in a ring configuration with an external mirror that feeds back only one of its two output beams. We compare the operation of the laser with and without an external feedback mirror. We find that the feedback mirror reduces significantly the spectral and power fluctuations. It is also responsible for an interesting spectral phenomenon: The laser frequency is drifting periodically over 9 nm at a rate of 2 nm/s from a short wavelength to a longer wavelength and vice versa.

  3. 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.

  4. Reverse spontaneous laser line sweeping in ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Navratil, P.; Peterka, P.; Honzatko, P.; Kubecek, V.

    2017-03-01

    Self-induced laser line sweeping of various regimes of sweep direction is reported for an experimental ytterbium fiber laser. The regimes involve sweeping from shorter to longer wavelengths (1076~\\text{nm}\\to 1083 nm)—so-called normal self-sweeping; from longer to shorter wavelengths (1079~\\text{nm}\\to 1073 nm)—so-called reverse self-sweeping; and a mixed regime in which a precarious balance of the normal and reverse sweeping exists and the sweep direction can change between consecutive sweeps. The regimes of sweeping were selected by changing the pump wavelength only. A detailed explanation of this sweep direction dynamics is presented based on a semi-empirical model. This model also provides a way to predict the sweep direction of fiber lasers based on other rare-earth-doped laser media.

  5. Electron gyroharmonic effects on ionospheric stimulated Brillouin scatter

    NASA Astrophysics Data System (ADS)

    Mahmoudian, A.; Scales, W. A.; Bernhardt, P. A.; Isham, B.; Kendall, E.; Briczinski, S. J.; Fuentes, N. E. B.; Vega-Cancel, O.

    2014-08-01

    Stimulated Brillouin scattering (SBS) and resonant phenomena are well known in the context of laser fusion, fiber optics, and piezoelectric semiconductor plasmas, as well as in various biological applications. Due to recent advances, active space experiments using high-power high-frequency (HF) radio waves may now produce stimulated Brillouin scattering (SBS) in the ionospheric plasma. The sensitivity of the narrowband SBS emission lines to pump frequency stepping across electron gyroharmonics is reported here for the first time. Experimental observations show that SBS emission sidebands are suppressed as the HF pump frequency is stepped across the second and third electron gyroharmonics. A correlation of artificially enhanced airglow and SBS emission lines excited at the upper hybrid altitude is observed and studied for second gyroharmonic heating. The SBS behavior near electron gyroharmonics is shown to have important diagnostic applications for multilayered, multi-ion component plasmas such as the ionosphere.

  6. Wavelength-codified fiber laser hydrogen detector

    NASA Astrophysics Data System (ADS)

    Ortigosa-Blanch, A.; Díez, A.; González-Segura, A.; Cruz, J. L.; Andrés, M. V.

    2005-11-01

    We report a scheme for an optical hydrogen detector that codifies the information in wavelength. The system is based on an erbium-doped fiber laser with two coupled cavities and a Palladium-coated tapered fiber within one of the laser cavities. The tapered fiber acts as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses. This change leads the system to switch lasing from the wavelength of the auxiliary cavity to the characteristic wavelength of the cavity which contains the sensing element. The detection level can be shifted by adjusting the reflective elements of the cavity containing the sensing element.

  7. Powerful narrow linewidth random fiber laser

    NASA Astrophysics Data System (ADS)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2017-03-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  8. Powerful narrow linewidth random fiber laser

    NASA Astrophysics Data System (ADS)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2016-11-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  9. Electrically tunable liquid crystal photonic bandgap fiber laser

    NASA Astrophysics Data System (ADS)

    Olausson, Christina B.; Scolari, Lara; Wei, Lei; Noordegraaf, Danny; Weirich, Johannes; Alkeskjold, Thomas T.; Hansen, Kim P.; Bjarklev, Anders

    2010-02-01

    We demonstrate electrical tunability of a fiber laser using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an all-spliced laser cavity based on a liquid crystal photonic bandgap fiber mounted on a silicon assembly, a pump/signal combiner with single-mode signal feed-through and an ytterbium-doped photonic crystal fiber. The laser cavity produces a single-mode output and is tuned in the range 1040- 1065 nm by applying an electric field to the silicon assembly.

  10. Transverse modes switchable fiber laser based on few-mode fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Sun, Biao; Wang, Anting; Zhou, Yong; Gu, Chun; Lin, Zhongxi; Xu, Lixin; Ming, Hai

    2012-11-01

    Based on the few-mode fiber Bragg grating's reflection characteristics, we propose and demonstrate a transverse modes switchable fiber laser fiber laser, fundamental mode and 1st higher order modes, and the states be switched by tuning the laser's oscillating wavelength. The radial vector beam is also obtained by splitting the degenerated 1st higher order modes.

  11. Transmission characteristics of high-power 589-nm laser beam in photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ito, Meguru; Hayano, Yutaka; Saito, Norihito; Akagawa, Kazuyuki; Kato, Mayumi; Saito, Yoshihiko; Takazawa, Akira; Takami, Hideki; Iye, Masanori; Wada, Satoshi; Colley, Stephen A.; Dinkins, Matthew C.; Eldred, Michael; Golota, Taras I.; Guyon, Olivier; Hattori, Masayuki; Oya, Shin; Watanabe, Makoto

    2006-06-01

    We are developing Laser Guide Star Adaptive Optics (LGSAO) system for Subaru Telescope at Hawaii, Mauna Kea. We achieved an all-solid-state 589.159 nm laser in sum-frequency generation. Output power at 589.159 nm reached 4W in quasi-continuous-wave operation. To relay the laser beam from laser location to laser launching telescope, we used an optical fiber because the optical fiber relay is more flexible and easier than mirror train. However, nonlinear scattering effect, especially stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS), will happen when the inputted laser power increases, i.e., intensity at the fiber core exceed each threshold. In order to raise the threshold levels of each nonlinear scattering, we adopt photonic crystal fiber (PCF). Because the PCF can be made larger core than usual step index fiber (SIF), one can reduce the intensity in the core. We inputted the high power laser into the PCF whose mode field diameter (MFD) is 14 μm and the SIF whose MFD is 5 μm, and measured the transmission characteristics of them. In the case of the SIF, the SRS was happen when we inputted 2 W. On the other hand, the SRS and the SBS were not induced in the PCF even for an input power of 4 W. We also investigated polarization of the laser beam transmitting through the PCF. Because of the fact that the backscattering efficiency of exciting the sodium layer with a narrowband laser is dependent on the polarization state of the incident beam, we tried to control the polarization of the laser beam transmitted the PCF. We constructed the system which can control the polarization of input laser and measure the output polarization. The PCF showed to be able to assume as a double refraction optical device, and we found that the output polarization is controllable by injecting beam with appropriate polarization through the PCF. However, the Laser Guide Star made by the beam passed through the PCF had same brightness as the state of the polarization.

  12. 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.

  13. Performance analysis of CO2 laser polished angled ribbon fiber

    NASA Astrophysics Data System (ADS)

    Sohn, Ik-Bu; Choi, Hun-Kook; Noh, Young-Chul; Lee, Man-Seop; Oh, Jin-Kyoung; Kim, Seong-min; Ahsan, Md. Shamim

    2017-01-01

    This paper demonstrates CO2 laser assisted simultaneous polishing of angled ribbon fibers consisting eight set of optical fibers. The ribbon fibers were rotated vertically at an angle of 12° and polished by repetitive irradiation of CO2 laser beam at the end faces of the fibers. Compared to mechanically polished sharp edged angled fibers, CO2 laser polishing forms curve edged angled fibers. Increase in the curvature of the end faces of the ribbon fibers causes the increase of the fibers' strength, which in turn represents great robustness against fiber connections with other devices. The CO2 laser polished angled fibers have great smoothness throughout the polished area. The smoothness of the fiber end faces have been controlled by varying the number of laser irradiation. After CO2 laser polishing, the average value of the fiber angle of the ribbon fibers is ∼8.28°. The laser polished ribbon fibers show low insertion and return losses when connecting with commercial optical communication devices. The proposed technique of polishing the angled ribbon fibers is highly replicable and reliable and thus suitable for commercial applications.

  14. 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.

  15. High Power Multimode Fiber Master Oscillator Power Amplifier (MOPA) with Stimulated Brillouin Scattering (SBS) Beam Cleanup and Phase Conjugation

    DTIC Science & Technology

    2011-09-01

    through the isolator and into the fiber designed for SBS beam cleanup, generally a long, graded - index (GI) fiber. Here, we use a 2.7-km GI 50/125...Yb-doped fiber amplifier (12). The delivery fiber has a numerical aperture of 0.06; the output is collimated to a 3.0 mm diameter with a 25-mm...were not used. To obtain the backward Stokes beam, light at λ L is focused with a 30-mm focal length doublet into a 2.7-km graded - index fiber with a

  16. 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

  17. 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.

  18. 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

  19. Multi-watt 589nm fiber laser source

    NASA Astrophysics Data System (ADS)

    Dawson, Jay W.; Drobshoff, Alex D.; Beach, Raymond J.; Messerly, Michael J.; Payne, Stephen A.; Brown, Aaron; Pennington, Deanna M.; Bamford, Douglas J.; Sharpe, Scott J.; Cook, David J.

    2006-02-01

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichio-metric 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 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 1088nm 4-level laser transition. At 15W, the 938nm laser has an M2 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Wavelength division and subcarrier system based on Brillouin amplification

    NASA Astrophysics Data System (ADS)

    Lee, Yang-Han; Wu, Jingshown; Kao, Ming-Seng; Tsao, Hen-Wai

    1991-10-01

    This paper analyzes an optical wavelength division multiplexing system (WDM) with subcarrier multiplexing (SCM). The pump laser is tuned to amplify the corresponding optical carrier by fiber Brillouin amplification (FBA) in WDM for the desired group of SCM signals and then a microwave tuner is used to select the desired channel in this group. This system has the benefits of eliminating the need of polarization control, the ability of phase noise cancelling due to the 'squaring' photodetection process of the selected optical carrier together with its SCM channels, and enhancement of optical receiver sensitivities by amplification of the carrier.

  6. Soliton modulation instability in fiber lasers

    NASA Astrophysics Data System (ADS)

    Tang, D. Y.; Zhao, L. M.; Wu, X.; Zhang, H.

    2009-08-01

    We report experimental evidence of soliton modulation instability in erbium-doped fiber lasers. An alternate type of spectral sideband generation was always experimentally observed on the soliton spectrum of the erbium-doped soliton fiber lasers when energy of the formed solitons reached beyond a certain threshold value. Following this spectral sideband generation, if the pump power of the lasers was further increased, either a new soliton would be formed or the existing solitons would experience dynamical instabilities, such as the period-doubling bifurcations or period-doubling route to chaos. We point out that the mechanism for this soliton spectral sideband generation is the modulation instability of the solitons in the lasers. We further show that, owing to the internal energy balance of a dissipative soliton, modulation instability itself does not destroy the stable soliton evolution in a laser cavity. It is the strong resonant wave coupling between the soliton and dispersive waves that leads to the dynamic instability of the solitons.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Self-Centering of a Ball Lens by Laser Trapping: Fiber-Ball-Fiber Coupling Analysis

    NASA Astrophysics Data System (ADS)

    Gauthier, Robert C.; Friesen, Michael; Gerrard, Thomas; Hassouneh, Wissam; Koziorowski, Piotr; Moore, Damian; Oprea, Karen; Uttamalingam, Sivasanker

    2003-03-01

    Fiber-to-fiber coupling through use of a laser-trapped microball lens is examined. A model based on radiation pressure predicts that the ball lens will align axially between the fiber endfaces. Laser manipulation of the ball lens axial position results in a configuration in which the ball lens optically bridges the gap between the fibers. Experimental results are presented for several fiber endface separations, and it is found that the presence of the microball lens can increase the coupling by a factor of 2 above the level expected by direct fiber-to-fiber coupling for the same fiber endface separation.

  13. Pressure-gradient fiber laser hydrophone

    NASA Astrophysics Data System (ADS)

    Zhang, Wentao; Zhang, Faxiang; Li, Fang; Liu, Yuliang

    2009-10-01

    A pressure-gradient fiber laser hydrophone (FLH) is demonstrated. Two brass diaphragms are installed at the end of a metal cylinder as the sensing element. There are two orifices at the middle of the cylinder. This structure can work as a pressure-gradient microphone in the acoustic field. Thus the DFB fiber laser fixed at the center of the two diaphragms is elongated or shortened due to the acoustic wave. Theoretical analysis is given based on the electro-acoustic theory. Experiments are carried out to test the performance of the hydrophone. A sensitivity of 100 nm/MPa has been achieved. Furthermore, the hydrostatic pressure is self-compensated and a ultra-thin dimension is achieved based on the proposed structure.

  14. 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.

  15. Germanate Glass Fiber Lasers for High Power

    DTIC Science & Technology

    2016-01-04

    germanate based glasses with a specific focus on glass stability during thermal- cycling which is representative of the steps required to fabricate a doped...evidence of crystallisation after thermal cycling , and is of a low enough loss to realize a fiber laser. The glass stability is demonstrated by...specific focus on glass stability during thermal- cycling which is representative of the steps required to fabricate a doped micro-structured germanate

  16. Femtosecond fiber-laser-based, laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Huan; Yang, Lih-Mei; Liu, Jian

    2012-06-01

    This paper reports the LIBS studies on elemental composition detection and identification by employing a femtosecond (fs) fiber laser. High quality LIBS spectra were obtained in air using near-infrared fs fiber laser coupled with a broadband high sensitivity spectrometer without gating control. Specific ion and neutral emission lines of different materials have been characterized by line scanning, including metals, glasses and even explosive materials. Different laser parameters including pulse energy, repetition rate, scanning speed and integration times have been investigated to optimize the sensitivity. Results show that faster scanning speed and higher pulse energies can greatly enhance the signal level and reduce the integration time. The LIBS spectra are highly reproducible at different repetition rates up to 1 MHz. Furthermore, detection of explosive materials was also achieved and both the constituent elemental emission and the CN and C2 molecules emission were collected. Compared with conventional LIBS, fs fiber laser based LIBS system have advantages of less sample heating and damage, better spatial resolution and signal to background ratio, compact, reliable and cost-effective. This shows a potential portable LIBS system for versatile and rapid analysis of chemical and special explosive materials.

  17. 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.

  18. Optical pulse generation using fiber lasers and integrated optics

    SciTech Connect

    Wilcox, R.B.; Browning, D.F.; Burkhart, S.C.; VanWonterghem, B.W.

    1995-03-27

    We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics.

  19. Mechanical reliability of double clad fibers in typical fiber laser deployment conditions

    NASA Astrophysics Data System (ADS)

    Walorny, Michael; Abramczyk, Jaroslaw; Jacobson, Nick; Tankala, Kanishka

    2016-03-01

    With the rapid acceptance of fiber lasers and amplifiers for various materials processing and defense applications the long term optical and mechanical reliability of the fiber laser, and therefore the components that make up the laser, is of significant interest to the industrial and defense communities. The double clad fiber used in a fiber laser is a key component whose lifetime in typical deployment conditions needs to be understood. The optical reliability of double clad fiber has recently been studied and a predictive model of fiber lifetime has been published. In contrast, a rigorous model for the mechanical reliability of the fiber and an analysis of the variables affecting the lifetime of the fiber in typical deployment conditions has not been studied. This paper uses the COST-218 model which is widely used for analyzing the mechanical lifetime of fiber used in the telecom industry. The factors affecting lifetime are analyzed to make the reader aware of the design choices a laser manufacturer can make, and the information they must seek from fiber suppliers, to ensure excellent lifetime for double clad fiber and consequently for the fiber laser. It is shown that the fiber's stress corrosion susceptibility, its proof strength, the coil diameter and the length of fiber coiled to achieve good beam quality all have important implications on fiber lifetime.

  20. Application of Levenberg-Marquardt algorithm in the Brillouin spectrum fitting

    NASA Astrophysics Data System (ADS)

    Zhang, Chuankai; Yang, Yuanhong; Li, Anqi

    2008-10-01

    Brillouin distributed optical fiber sensing system based on spontaneous Brillouin scattering frequency shift measurement may measure temperature in the optical fiber, due to the dependence of spontaneous Brillouin scattering frequency shift on temperature. In this paper, nonlinear theoretical models of the Brillouin spectrum in the BOTDR temperature sensing system are analyzed. The model parameters are optimized with Levenberg-Marquardt algorithm. By numerical calculation, it is indicated that pseudo-Voigt function can approach approximated the Voigt profile well and quickly.

  1. Anti-reflection coated optical fibers for use in thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

    2017-02-01

    The Thulium fiber laser (TFL) is being studied as an alternative to Holmium:YAG laser for lithotripsy. The near single mode TFL beam profile enables transmission of higher laser power through smaller optical fibers than possible during Holmium laser lithotripsy. Current free-space coupling of collimated TFL output beam into a disposable silica fiber for ureteroscopy is limited by back-reflected light from the fiber input surface, which may result in laser shutoff or damage, if left unchecked. This study examines whether anti-reflection (AR) coated fibers may sufficiently reduce back-reflected light to prevent laser shutoff, increase fiber optic transmission, and potentially increase laser stone ablation rates as well. Fiber optic transmission and stone ablation studies were conducted comparing uncoated and AR-coated 105- and 200-μm-core fibers. Magnified images of proximal fiber surfaces were taken before and after each trial to examine for AR-coating damage. TFL wavelength of 1908 nm was coupled into silica fibers, with incrementally increasing pulse energy (5-35 mJ), fixed 500-μs pulse duration, and pulse rates of 50-300 Hz. For each pulse rate, 100,000 pulses were also delivered through the fibers to examine for potential damage. Back-reflection at proximal fiber surface was reduced from 3.25% with uncoated fibers to 0.06% with AR coated fibers. For both fiber diameters, output power was stable, and no proximal fiber damage was observed after delivery of 100,000 pulses at 35 mJ, 300 Hz, and 10.5 W average power. There was no significant difference in stone ablation rates between fiber diameters (105 vs. 200 μm) or bare or AR-coated fibers. Laser shutdown was not observed using AR-coated fibers, which reduce back-reflection and improve energy transmission, but do not improve stone ablation rates.

  2. Comparison of core fibers and contact probes for laser surgery

    NASA Astrophysics Data System (ADS)

    Steiner, Rudolf W.; Keckstein, J.; Finger, Anthonio

    1990-07-01

    Advanced laser operational techniques have been introduced using the Nd:YAG or the argon laser in combination with fiber techniques and contact probes . In gynaecology, for exantple, surgeons need highly flexible fiber transmission systems for laparoscopic operations 2 Indications such as adhesiolysis or endornetriosis can be treated without mechanical traumatisation and bleeding using the laser light. Laser systems with different wavelengths, fibers and tips have become a very flexible surgical instrument. Feedback control of the reaction of the laser light with tissue makes the inedical laser system save and reliable.

  3. 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.

  4. Q-switched all-fiber lasers with saturable absorbers

    NASA Astrophysics Data System (ADS)

    Kurkov, A. S.

    2011-05-01

    In this brief review we consider the relatively new design of the pulsed fiber lasers, namely lasers with the fiber saturable absorber (FSA). Main advantage of this design consists in a possibility to realize a simple all-fiber scheme of Q-switched laser. We show that such lasers can be based on the different types of the fiber absorber and operate in the different spectral ranges. Up to now a set of the pulsed lasers were build. Pulse energy from several μJ to several hundred μJ was demonstrated. Pear power was changed from tens W to several kW with the pulse duration from 50 ns to 1 μs. We show that described principles of Q-switching can be applied for other types of the fiber lasers. Also, new fiber absorbers are suggested.

  5. 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.

  6. Comparative study of ring and random cavities for fiber lasers.

    PubMed

    Fernandez-Vallejo, Montserrat; Rota-Rodrigo, Sergio; Lopez-Amo, Manuel

    2014-06-01

    An experimental comparison of three fiber laser structures with the same Raman gain medium is presented in order to establish the main pros and cons of each basic scheme. The first fiber laser is based on a hybrid ring-random fiber laser, the second one is a pure ring fiber laser, and the last one is a random fiber laser. Several aspects have been taken into account in the study. First, from the optical point of view, the parameters of interest compared are output power, lasing threshold, slope efficiency, power fluctuations, and the longitudinal modes have been analyzed. Second, the possible utilization of fiber lasers in digital modulated optical communication systems is also studied.

  7. 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.

  8. Numerical simulation for optimization of temporal gatings in Brillouin optical correlation domain analysis

    NASA Astrophysics Data System (ADS)

    Yamashita, Rodrigo K.; Hotate, Kazuo

    2013-05-01

    Brillouin sensors have the potential to measure strain or temperature distribution along the optical fiber, by determination of the Brillouin frequency shift (BFS). The Brillouin optical correlation domain analysis (BOCDA) is an important technique in Brillouin sensors, having great spatial resolution over a restricted measurement range, comparing to other systems, such as the Brillouin optical time domain analysis (BOTDA). To elongate the restricted measurement range, temporal gating techniques have been proposed and demonstrated, but the influence of these techniques on the performance of the BOCDA system or the parameter requirement for system optimization have not been investigated. In this report, we first determine a simulation method to calculate the BOCDA output with temporal gatings and find out that the phase relation between the gating pulses and the sinusoidal frequency modulation (FM) may change the system output. Although that influence can be neglected for most cases, the phase optimization can make the system output approach the ideal case that the temporal gating is not being applied. Finally, calculations of system output for different gating pulse lengths are held, showing that the pulse length does not have to strictly match one period of the sinusoidal FM of the laser source.

  9. Thulium-doped all-fiber mode-locked laser synchronously pumping by a fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Gen; Hu, Yangyang; Yan, Ke; Zhang, Chun; Zhang, Junyi; Gu, Chun; Xu, Lixin

    2016-09-01

    We demonstrate a thulium-doped all fiber actively mode-locked laser by synchronously pumping without electronic modulator. A mode-locked fiber laser operating at 1550 nm based on nonlinear polarization rotation (NPR) is innovatively utilized as the pulsed pump. Through cavity length matching, stable mode-locking that operate at 1891.25 nm is achieved with a spectral width of 0.52 nm at 3 dB. The repetition rate is 11.59 MHz with an estimated pulse duration less than 125 ps.

  10. Photodegradation of fluoride glass blue fiber laser

    NASA Astrophysics Data System (ADS)

    Chandonnet, Alain; Laperle, Pierre; LaRochelle, Sophie; Vallee, Real

    1997-01-01

    The first demonstration of blue upconversion fiber lasers in Tm-ZBLAN has generated considerable interest among laser scientists looking for all-solid-state visible sources. Although initial experiments have shown a large conversion efficiency, a good spatial beam quality and an overall simplicity of the approach, these sources have not yet appeared on the market. In an attempt to reproduce these early results, many research teams including our own have encountered unexplained and detrimental start-up effects in these lasers. We have recently shown that this behavior is the result of photochromic damage in the fluoride fibers generated by the infrared pumping source. Progressive build- up of photoinduced loss ultimately prevents operation of the device. The photoinduced absorption spectrum extends from the UV to the near infrared, with three major bands centered around 300 nm, 500 nm and 800 nm. Pump-probe experiments show that the damage mechanism depends on the Tm3+ concentration and that it follows a fourth power dependence on the pumping intensity. Further investigation has revealed that photobleaching of the defects is possible using visible and near infrared radiation. The residual absorption spectrum following photobleaching suggests that three different species of defects are created. One type of defects is related to the 800 nm band and can be permanently removed. The other two are only temporarily removed by photobleaching and reappear on a time-scale of a few minutes. In addition, thermal bleaching can completely erase the defects in certain fibers. This paper summarizes the current understanding of photoinduced phenomena occurring in Tm3+-ZBLAN fibers.

  11. Highly-efficient high-power pumps for fiber lasers

    NASA Astrophysics Data System (ADS)

    Gapontsev, V.; Moshegov, N.; Berezin, I.; Komissarov, A.; Trubenko, P.; Miftakhutdinov, D.; Berishev, I.; Chuyanov, V.; Raisky, O.; Ovtchinnikov, A.

    2017-02-01

    We report on high efficiency multimode pumps that enable ultra-high efficiency high power ECO Fiber Lasers. We discuss chip and packaged pump design and performance. Peak out-of-fiber power efficiency of ECO Fiber Laser pumps was reported to be as high as 68% and was achieved with passive cooling. For applications that do not require Fiber Lasers with ultimate power efficiency, we have developed passively cooled pumps with out-of-fiber power efficiency greater than 50%, maintained at operating current up to 22A. We report on approaches to diode chip and packaged pump design that possess such performance.

  12. High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-01

    demonstrated in a moder- ately turbulent environment. HIgH-PowEr FIbEr LAsErs Although a number of companies manufacture high-power fiber lasers , IPG ...in approximately one year. Multi- kilowatt , single-mode fiber lasers are robust, compact, and have high wall- plug efficiency, random polarization...and large band- width (~0.1%). A 1 kW, single-mode IPG fiber laser module, operating at wavelength l = 1.075 μm, exclud- ing power supply, measures w

  13. Single-end simultaneous temperature and strain sensing techniques based on Brillouin optical time domain reflectometry in few-mode fibers.

    PubMed

    Weng, Yi; Ip, Ezra; Pan, Zhongqi; Wang, Ting

    2015-04-06

    Recently there is a growing interest in developing few-mode fiber (FMF) based distributed sensors, which can attain higher spatial resolution and sensitivity compared with the conventional single-mode approaches. However, current techniques require two lightwaves injected into both ends of FMF, resulting in their complicated setup and high cost, which causes a big issue for geotechnical and petroleum applications. In this paper, we present a single-end FMF-based distributed sensing system that allows simultaneous temperature and strain measurement by Brillouin optical time-domain reflectometry (BOTDR) and heterodyne detection. Theoretical analysis and experimental assessment of multi-parameter discriminative measurement techniques applied to distributed FMF sensors are presented. Experimental results confirm that FM-BOTDR has similar performance with two-end methods such as FM-BOTDA, but with simpler setup and lower cost. The temperature-induced expansion strain (TIES) in response to different modes is discussed as well. Furthermore, we optimized the FMF design by exploiting modal profile and doping concentration, which indicates up to fivefold enhancement in measurement accuracy. This novel distributed FM-sensing system endows with good sensitivity characteristics and can prevent catastrophic failure in many applications.

  14. 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

  15. Laser Brazing metallic embedding technique for fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Grandal, Tania; Fraga, Sergio; Castro, Gemma; Vazquez, Esteban; Zornoza, Ander

    2017-04-01

    In this paper a fiber optic metallic embedding technique is presented based on laser Brazing manufacturing process. The embedding strategy to follow by the laser Brazing, which consists in three steps, minimizes the thermal stress of the embedded fiber, relaxes microbending strains and reduces damage on the fiber. The minimum embedded fiber optic Ni coating total diameter is 237 μm for a successful process with negligible optical loss on the fiber. Fiber Bragg Gratings were successfully embedded in metallic specimens and their strain response was in accordance with their specifications.

  16. CO2 laser polishing of conical shaped optical fiber deflectors

    NASA Astrophysics Data System (ADS)

    Şimşek, Elif Uzcengiz; Şimşek, Bartu; Ortaç, Bülend

    2017-06-01

    A novel method for polishing conical shaped optical fiber deflectors by modulated CO2 laser exposure is reported. The conical shaped fiber deflector geometry was first formed with rough mechanical polishing, then it was exposed to modulated CO2 laser operating with wavelength at 10.6 µm to achieve fine polish surfaces. The motivation of this work is to demonstrate that the modulated CO2 laser exposure approach allows a fiber surface roughness at a nanometer scale without modifying the conical shape of the fiber deflector. The average surface roughness of mechanically polished fiber deflectors with 30 and 9 µm lapping films was smoothed down to 20.4 and 4.07 nm, respectively, after CO2 laser polishing process. By combining mechanical and laser polishing techniques, fabrication of conical shaped optical fiber deflectors takes less time and it becomes laborer independent and easy to apply.

  17. Yb3+ doped ribbon fiber for high-average power lasers and amplifiers

    NASA Astrophysics Data System (ADS)

    Drachenberg, Derrek R.; Messerly, Michael J.; Pax, Paul H.; Sridharan, Arun K.; Tassano, John B.; Dawson, Jay W.

    2014-03-01

    Diffraction-limited high power lasers in the region of 10s of kW to greater than 100 kW are needed for defense, manufacturing and future science applications. A balance of thermal lensing and Stimulated Brillouin Scattering (SBS) for narrowband amplifiers and Stimulated Raman Scattering (SRS) for broadband amplifiers is likely to limit the average power of circular core fiber amplifiers to 2 kW (narrowband) or 36 kW (broadband). A ribbon fiber, which has a rectangular core, operating in a high order mode can overcome these obstacles by increasing mode area without becoming thermal lens limited and without the on-axis intensity peak associated with circular high order modes. High order ribbon fiber modes can also be converted to a fundamental Gaussian mode with high efficiency for applications in which this is necessary. We present an Yb-doped, air clad, optical fiber having an elongated, ribbon-like core having an effective mode area of area of 600 μm² and an aspect ratio of 13:1. As an amplifier, the fiber produced 50% slope efficiency and a seed-limited power of 10.5 W, a gain of 24 dB. As an oscillator, the fiber produced multimode power above 40 W with 71% slope efficiency and single mode power above 5 W with 44% slope efficiency. The multimode M2 beam quality factor of the fiber was 1.6 in the narrow dimension and 15 in the wide dimension.

  18. Advances in fiber laser spectral beam combining for power scaling

    NASA Astrophysics Data System (ADS)

    Honea, Eric; Afzal, Robert S.; Savage-Leuchs, Matthias; Henrie, Jason; Brar, Khush; Kurz, Nathan; Jander, Don; Gitkind, Neil; Hu, Dan; Robin, Craig; Jones, Andrew M.; Kasinadhuni, Ravi; Humphreys, Richard

    2016-03-01

    Spectral Beam Combining (SBC) of fiber lasers provides a simple, robust architecture for high brightness power scaling beyond the limit of a single fiber. We review recent progress in power scaling and describe what we believe is the highest power SBC fiber demonstration and largest number of fiber lasers combined to date. Here we report results on a fiber SBC system where we achieved > 30 kW by combining 96 individual fiber lasers into a single high brightness beam with a beam quality of M2 = 1.6 x 1.8. The potential for further power scaling at the system level is highlighted with examples of beam combinable fiber laser power scaling.

  19. Plasticity of climbing fibers after laser axotomy

    NASA Astrophysics Data System (ADS)

    Allegra Mascaro, A. L.; Cesare, P.; Sacconi, L.; Grasselli, G.; Strata, P.; Pavone, F. S.

    2010-02-01

    In the adult nervous system, different population of neurons corresponds to different regenerative behavior. Although previous works show that olivocerebellar fibers are capable of axonal regeneration in a suitable environment as a response to injury1, we have hitherto no details about the real dynamics of fiber regeneration. We coupled two photon imaging to laser-induced lesions to perform in vivo multiphoton nanosurgery in the CNS of living mice expressing fluorescent proteins to investigate the reparative properties of Climbing Fibers (CFs) in the adult CNS, following the time evolution of this plastic process in vivo. Here we show that a regenerative event may take place in a murine model in the days that follow a sub-micrometric lesion on the distal portion of the climbing fiber. Furthermore this unique model could allow, through manipulation of the viral vector, to explore in detail the biochemical mechanisms underlying the reparative process. The great potential of long-term two photon imaging, coupled to genetic manipulation, opens great opportunities to further investigate the dynamic properties of neurons and their rearrangement following an injury.

  20. 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.

  1. Self-focusing and stimulated Brillouin back-scattering of a long intense laser pulse in a finite temperature relativistic plasma

    SciTech Connect

    Niknam, A. R.; Barzegar, S.; Hashemzadeh, M.

    2013-12-15

    The nonlinear dynamics of electromagnetic waves propagating through a plasma considering the effects of relativistic mass and ponderomotive nonlinearities is investigated. The modified electron density distribution, the dispersion relation, and the spatial profiles of electromagnetic wave amplitude in the plasma are obtained. It is shown that the cut-off frequency decreases, and there is an intensity range in which the ponderomotive self-focusing takes place. In the upper limit of this range, the laser beam is defocused due to the relativistic ponderomotive force. In addition, the stability of electromagnetic waves to stimulated Brillouin scattering is studied, and the backscattered wave resulting from decay of high power electromagnetic beam is resolved in relativistic regime. The study of effects of electron density and temperature on the growth rate of backscattered wave has been shown that by increasing these effects, the growth rate of instability increases.

  2. Time-Dependent Modeling of Brillouin Scattering in Optical Fibers Excited by a Chirped Diode Laser

    DTIC Science & Technology

    2012-10-31

    engineering from the Indian Institute of Technology Madras, Chennai , India, in 2005, and the M.S. and Ph.D. degrees in electrical engi- neering from the...control, coherent optics and optoelectron- ics, 3-D imaging , and biomedical optics. Dr. Satyan is a member of the Optical Society of America. Jeffrey O

  3. 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.

  4. High resolution fiber Bragg grating interrogation using a random distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Leandro, D.; Ardanaz, D.; Lopez-Amo, M.

    2015-09-01

    In this study, a new sensing application for random distributed feedback fiber lasers is presented. Temperature measurements of a phase-shifted fiber Bragg grating with a resolution higher than 0.01 ºC have been attained. The resolution limitation of classical fiber lasers has been overcome due to the absence of longitudinal modes and high frequency stability of random fiber lasers. The frequency shift of the grating has been measured as 1.195 ºC/GHz and it is detected in the electrical domain by beating an external laser source with the random emission line generated.

  5. Nonlinear dynamics of Ytterbium-doped fiber laser Q-switched using acousto-optical modulator

    NASA Astrophysics Data System (ADS)

    Barmenkov, Y. O.; Kir'yanov, A. V.; Andres, M. V.

    2014-12-01

    A comprehensive experimental analysis of the dynamics of an ytterbium-doped fiber laser actively Q-switched (QS) using an intracavity acousto-optical modulator (AOM) is presented. It is shown that type of QS pulsing strongly depends on AOM repetition rate and pump power. In particular, at low repetition rates, including zero-rate, and at relatively high pump powers peculiar QS pulsing, switched by stimulated Brillouin scattering (SBS), is established in the laser. The cause of such kind of pulsing is the SBS-process boosted by spurious narrow-line CW lasing that arises in auxiliary low-Q cavity formed by an output coupler (in our experiments - fiber Bragg gratings) and weak reflections from blocked AOM. The parameters' area where this regime occurs is limited by certain values of pump power and AOM repetition rate. At increasing AOM repetition rate or decreasing pump power spurious CW lasing is not attained in the system; consequently, the SBS type of QS fades, while "conventional" QS (CQS) lasing is established in the system and remains. However CQS pulsing strongly suffers the nonlinear-dynamics effects: depending on AOM repetition rate and pump power the laser switches to common P1, P2, or P3 attractors, when QS pulses arise at sub-harmonics of AOM repetition rate, or to the specific transient regimes between them, or to chaotic operation. These and other sides (e.g. pulse jittering) of operation of the QS ytterbium-doped fiber laser with AOM are under scope of the present review as they have big interest for practical applications.

  6. 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.

  7. Numerical modeling of mode-locked fiber lasers with a fiber-based saturable-absorber

    NASA Astrophysics Data System (ADS)

    Wang, Long; Chong, Andy; Haus, Joseph W.

    2017-01-01

    We report fiber laser simulations with a fiber compatible, self-focusing, saturable absorber (SA) device. The SA device consists of two tapered fiber ends separated by a bulk, nonlinear medium. An optical beam transmitted from one tapered fiber end, propagate through the nonlinear medium (chalcogenide glass As40 S e60) and couples back into the other tapered fiber end. Pulse propagation in the fiber laser cavity is performed using the Split Step Method. Stable pulses are generated with energies around 0.3 nJ and a transform limited pulse width around 200 fs.

  8. Investigation intensity response of distributed-feedback fiber laser to external acoustic excitation Investigation intensity response of DFB fiber laser

    NASA Astrophysics Data System (ADS)

    Wang, P. P.; Chang, J.; Zhu, C. G.; Wang, W. J.; Zhao, Y. J.; Zhang, X. L.; Peng, G. D.; Lv, G. P.; Liu, X. Z.; Wang, H.

    2012-08-01

    The intensity response of distributed-feedback (DFB) fiber laser to external acoustic excitation has been investigated. On that basis, an intensity modulated sensing system based on DFB fiber laser has been constructed. Acoustic pressure sensitivity of the intensity-type sensor at frequencies ranging from 800 Hz to 9 kHz has been obtained by experiments for the first time to the authors' knowledge. In addition, intensity response property of DFB fiber laser to external acoustic excitation with different pump power has been analyzed. We conclude that the signal power increases with the pump drive current of 980 nm laser diode (LD), and yet the ratios of signal power to DFB fiber laser power decrease. It confirms that the anti-interference performance of DFB fiber laser to fixed external acoustic interference becomes stronger with the increasing current of pump source, and this conclusion is beneficial to the investigation of wavelength demodulated sensors.

  9. Novel high-brightness fiber coupled diode laser device

    NASA Astrophysics Data System (ADS)

    Haag, Matthias; Köhler, Bernd; Biesenbach, Jens; Brand, Thomas

    2007-02-01

    High brightness becomes more and more important in diode laser applications for fiber laser pumping and materials processing. For OEM customers fiber coupled devices have great advantages over direct beam modules: the fiber exit is a standardized interface, beam guiding is easy with nearly unlimited flexibility. In addition to the transport function the fiber serves as homogenizer: the beam profile of the laser radiation emitted from a fiber is symmetrical with highly repeatable beam quality and pointing stability. However, efficient fiber coupling requires an adaption of the slow-axis beam quality to the fiber requirements. Diode laser systems based on standard 10mm bars usually employ beam transformation systems to rearrange the highly asymmetrical beam of the laser bar or laser stack. These beam transformation systems (prism arrays, lens arrays, fiber bundles etc.) are expensive and become inefficient with increasing complexity. This is especially true for high power devices with small fiber diameters. On the other hand, systems based on single emitters are claimed to have good potential in cost reduction. Brightness of the inevitable fiber bundles, though, is limited due to inherent fill-factor losses. At DILAS a novel diode laser device has been developed combining the advantages of diode bars and single emitters: high brightness at high reliability with single emitter cost structure. Heart of the device is a specially tailored laser bar (T-Bar), which epitaxial and lateral structure was designed such that only standard fast- and slow-axis collimator lenses are required to couple the beam into a 200μm fiber. Up to 30 of these T-Bars of one wavelength can be combined to reach a total of > 500W ex fiber in the first step. Going to a power level of today's single emitter diodes even 1kW ex 200μm fiber can be expected.

  10. 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.

  11. Distributed Raman amplification using ultra-long fiber laser with a ring cavity: characteristics and sensing application.

    PubMed

    Jia, Xin-Hong; Rao, Yun-Jiang; Wang, Zi-Nan; Zhang, Wei-Li; Yuan, Cheng-Xu; Yan, Xiao-Dong; Li, Jin; Wu, Han; Zhu, Ye-Yu; Peng, Fei

    2013-09-09

    Distributed Raman amplification (DRA) based on ultra-long fiber laser (UL-FL) pumping with a ring cavity is promising for repeaterless transmission and sensing. In this work, the characteristics (including gain, nonlinear impairment and noise figure) for forward and backward pumping of the ring-cavity based DRA scheme are fully investigated. Furthermore, as a typical application of the proposed configuration, ultra-long-distance distributed sensing with Brillouin optical time-domain analysis (BOTDA) over 142.2 km fiber with 5m spatial resolution and ± 1.5 °C temperature uncertainty is achieved, without any repeater. The key point for the significant performance improvement is the system could offer both of uniform gain distribution and considerably suppressed pump-probe relative intensity noise (RIN) transfer, by optimized design of system structure and parameters.

  12. Disordered microstructure polymer optical fiber for stabilized coherent random fiber laser.

    PubMed

    Hu, Zhijia; Miao, Bo; Wang, Tongxin; Fu, Qiang; Zhang, Douguo; Ming, Hai; Zhang, Qijin

    2013-11-15

    We have demonstrated the realization of a random polymer fiber laser (RPFL) based on laser dye Pyrromethene 597-doped one-dimensional disordered polymer optical fiber (POF). The stabilized coherent laser action for the disordered POF has been obtained by the weak optical multiple scattering of the polyhedral oligomeric silsesquioxanes nanoparticles in the core of the POF in situ formed during polymerization, which was enhanced by the waveguide confinement effect. Meanwhile, the threshold of our RPFL system is almost one order of magnitude lower than that of the liquid core random fiber laser reported previously, which promotes the development of random lasers.

  13. Packaging considerations of fiber-optic laser sources

    NASA Astrophysics Data System (ADS)

    Heikkinen, Veli; Tukkiniemi, Kari; Vaehaekangas, Jouko; Hannula, Tapio

    1991-12-01

    The continuous progress in material and component technology has generated new laser-based applications that require special packaging techniques. Hybrid integration offers a flexible method to accomplish custom design needs. This paper discusses several aspects in fiber optic packaging including optical, thermal, and mechanical issues. Special emphasis is on optical coupling between a laser diode and a single-mode fiber.

  14. Phase locking of a 275 W high power all-fiber amplifier seeded by two categories of multi-tone lasers.

    PubMed

    Wang, Xiaolin; Leng, Jingyong; Zhou, Pu; Du, Wenbo; Xiao, Hu; Ma, Yanxing; Dong, Xiaolin; Xu, Xiaojun; Liu, Zejin; Zhao, Yijun

    2011-04-11

    Multi-tone radiation is a promising technique to suppress stimulated Brillouin scattering (SBS) effects and improve the ultimate output power of the fiber laser/amplifier. Coherent beam combining of fiber lasers/ amplifiers is another feasible way to increase the output laser power from single gain medium while simultaneously maintaining good beam quality. In this paper, we combine the multi-tone driven all-fiber amplifiers and active phase compensation to demonstrate high power phase locking for coherent beam combining. First, we present the theory of coherent beam combining of multi-tone lasers. Second, we optimize the all-fiber power amplifier oscillator power-amplifier (MOPA) system with high scalability and flexibility based on compact, high efficiency Yb-doped fiber amplifier chains. Then, two categories of multi-tone master oscillators are used to driven the amplifier chains. The first category is two coupled single-frequency lasers and the second is a frequency modulated single-frequency laser. The output powers are all boosted to 275 W without any distinct SBS. Last, phase locking of the amplifier chains are implemented using stochastic parallel gradient descent (SPGD) algorithm. Scaling this configuration to a higher power involves increasing the power per chain and adding the number of amplifier channels.

  15. 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.

  16. Narrow-band generation in random distributed feedback fiber laser.

    PubMed

    Sugavanam, Srikanth; Tarasov, Nikita; Shu, Xuewen; Churkin, Dmitry V

    2013-07-15

    Narrow-band emission of spectral width down to ~0.05 nm line-width is achieved in the random distributed feedback fiber laser employing narrow-band fiber Bragg grating or fiber Fabry-Perot interferometer filters. The observed line-width is ~10 times less than line-width of other demonstrated up to date random distributed feedback fiber lasers. The random DFB laser with Fabry-Perot interferometer filter provides simultaneously multi-wavelength and narrow-band (within each line) generation with possibility of further wavelength tuning.

  17. 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.

  18. Brillouin Optical Microscopy for Corneal Biomechanics

    PubMed Central

    Scarcelli, Giuliano; Pineda, Roberto

    2012-01-01

    Purpose. The mechanical properties of corneal tissue are linked to prevalent ocular diseases and therapeutic procedures. Brillouin microscopy is a novel optical technology that enables three-dimensional mechanical imaging. In this study, the feasibility of this noncontact technique was tested for in situ quantitative assessment of the biomechanical properties of the cornea. Methods. Brillouin light-scattering involves a spectral shift proportional to the longitudinal modulus of elasticity of the tissue. A 532-nm single-frequency laser and a custom-developed ultrahigh-resolution spectrometer were used to measure the Brillouin frequency. Confocal scanning was used to perform Brillouin elasticity imaging of the corneas of whole bovine eyes. The longitudinal modulus of the bovine corneas was compared before and after riboflavin corneal collagen photo-cross-linking. The Brillouin measurements were then compared with conventional stress–strain mechanical test results. Results. High-resolution Brillouin images of the cornea were obtained, revealing a striking depth-dependent variation of the elastic modulus across the cornea. Along the central axis, the Brillouin frequency shift varied gradually from 8.2 GHz in the epithelium to 7.5 GHz near the endothelium. The coefficients of the down slope were measured to be approximately 1.09, 0.32, and 2.94 GHz/mm in the anterior, posterior, and innermost stroma, respectively. On riboflavin collagen cross-linking, marked changes in the axial Brillouin profiles (P < 0.001) were noted before and after cross-linking. Conclusions. Brillouin imaging can assess the biomechanical properties of cornea in situ with high spatial resolution. This novel technique has the potential for use in clinical diagnostics and treatment monitoring. PMID:22159012

  19. New generation high-power rare-earth-doped phosphate glass fiber and fiber laser

    NASA Astrophysics Data System (ADS)

    Wu, Ruikun; Myers, John D.; Myers, Michael J.

    2001-04-01

    High power, high brightness fiber lasers have numerous potential commercial and military applications. Fiber lasers with cladding pump designs represent a new generation of diode pumped configurations that are extremely efficient, have single mode output and may be operated with or without active cooling. Kigre has invented a new family of Er/Yb/Nd phosphate laser glass materials (designated QX) that promise to facilitate a quantum leap in fiber laser technology of this field. The new phosphate glass Rare-Earth doped fiber exhibit many advantages than Silica or Fluoride base fiber, see table.1. Instead of 30 to 50 meters of fused silica with a 50 mm bend radii; Kigre's phosphate glass fiber amplifiers may be designed to be less than 4 meters long .Laser performance and various design parameters, such as the fiber core diameter, NA, inner cladding shape and doping concentration are evaluated. Laser performances was demonstrated for an experimental QX/Er doubled clading fiber commissioned by MIT having 8 micron core, a 240 X 300 micron rectangle shaped inner cladding with 0.4 NA and 500 micron outer clading.. Kigre obtained approximately 2 dB/cm gain from 15cm long fiber under 940nm pumping The same fiber was evaluated by researcher at MIT. They used 975nm pump source. Maximum 270mW output was demonstrated by 30 cm long fiber with Fresnel reflection resonator mirrors. The slope efficiency of absorbed pump power s 47%.

  20. Switchable dual-mode all-fiber laser with few-mode fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Jin, Wenxing; Qi, Yanhui; Yang, Yuguang; Jiang, Youchao; Wu, Yue; Xu, Yao; Yao, Shuzhi; Jian, Shuisheng

    2017-09-01

    We propose a new approach to realize switchable mode operation in a few-mode erbium-doped fiber laser. The ring fiber laser structure is constructed with a core-offset splicing between single-mode fiber and dual-mode fiber. Stable operating on the fundamental mode laser and second-order mode laser individually or simultaneously is realized by appropriately adjusting the state of the polarization controller and bending status of the few-mode fiber Bragg grating. The narrow 3 dB linewidth less than 0.02 nm and high optical signal to noise ratio more than 42 dB are obtained for both modes in either separate laser or simultaneous laser operating conditions.

  1. Narrow linewidth Yb-doped fiber laser at 1120 nm.

    PubMed

    Xiaojuan, Liu; Shenggui, Fu; Liping, Guo; Kezhen, Han

    2013-03-20

    A 974 nm laser diode pumped 1120 nm ytterbium (Yb)-doped fiber laser with all fiber components has been experimentally demonstrated. The resonator is composed of a normal single-mode Yb-doped fiber 1 m long and a pair of fiber Bragg gratings. Up to 21.6 mW of continuous-wave output power is generated when the launched pump power is 161 mW with an optical-to-optical conversion efficiency of 13.4%. The central wavelength is 1120.89 nm with a linewidth as narrow as 0.02 nm. Additionally, a similar fiber laser with a 2 m long gain medium displays a broadened linewidth. The results of the two fiber lasers are compared and discussed in the paper.

  2. Frequency noise in frequency swept fiber laser.

    PubMed

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-04-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto- optical modulators and forward propagating Brillouin scattering appear in the spectrum.

  3. Spectral properties of thulium doped optical fibers for fiber lasers around 2 micrometers

    NASA Astrophysics Data System (ADS)

    Kamrádek, M.; Aubrecht, J.; Peterka, P.; Podrazký, O.; Honzátko, P.; Cajzl, J.; Mrázek, J.; Kubeček, V.; Kašik, I.

    2017-05-01

    Silica optical fibers doped with rare-earth elements are key components of high-power fiber lasers operating in near-infrared region up to 2.1 μm. In this contribution we deal with preparation and optical characterization of silica-based optical preforms and fibers doped with thulium for fiber lasers operating around 2 μm. A set of fibers with thulium concentration ranges 1000-5000 ppm was prepared by the MCVD solution doping method and characterized. A decrease of fluorescence lifetime of thulium from 487 μs to 378 μs was observed with increasing rare-earth concentration in fiber core. This phenomenon can be explained by energy transfer between ions and ion clustering. Fabricated fibers were suitable for use in fiber lasers.

  4. Multimode laser emission from dye doped polymer optical fiber.

    PubMed

    Sheeba, Mavila; Thomas, Kannampuzha J; Rajesh, Mandamparambil; Nampoori, Vadakkedathu P N; Vallabhan, Chakkalakkal P G; Radhakrishnan, Padmanabhan

    2007-11-20

    Multimode laser emission is observed in a polymer optical fiber doped with a mixture of Rhodamine 6G (Rh 6G) and Rhodamine B (Rh B) dyes. Tuning of laser emission is achieved by using the mixture of dyes due to the energy transfer occurring from donor molecule (Rh 6G) to acceptor molecule (Rh B). The dye doped poly(methyl methacrylate)-based polymer optical fiber is pumped axially at one end of the fiber using a 532 nm pulsed laser beam from a Nd:YAG laser and the fluorescence emission is collected from the other end. At low pump energy levels, fluorescence emission is observed. When the energy is increased beyond a threshold value, laser emission occurs with a multimode structure. The optical feedback for the gain medium is provided by the cylindrical surface of the optical fiber, which acts as a cavity. This fact is confirmed by the mode spacing dependence on the diameter of the fiber.

  5. 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.

  6. Optical fiber transmission of high power excimer laser radiation.

    PubMed

    Pini, R; Salimbeni, R; Vannini, M

    1987-10-01

    An experimental investigation of optical fiber transmission of high power excimer laser radiation is presented. Different types of commercially available UV fiber have been tested, measuring energy handling capabilities and transmission losses of short samples at the XeCl (308-nm) and KrF (249-nm) wavelengths by using a standard excimer laser. A power density dependent damage process has been observed over 1 GW/cm(2). Fiber losses due to different radii of curvature are also reported. Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose. Finally, optimum excimer laser characteristics to increase the energy coupling in fibers are discussed.

  7. Overcoming non-local effects and Brillouin threshold limitations in Brillouin distributed sensors

    NASA Astrophysics Data System (ADS)

    Urricelqui, Javier; Ruiz-Lombera, Rubén.; Sagues, Mikel; Mirapeix, Jesús; López-Higuera, José M.; Loayssa, Alayn

    2015-09-01

    We demonstrate, for the first time to our knowledge, a Brillouin optical time domain analysis sensor that is able to operate with a probe power larger than the Brillouin threshold of the deployed sensing fiber and that is free from detrimental non-local effects. The technique is based on a dual-probe-sideband setup in which a frequency modulation of the probes waves along the fiber is introduced. This makes the frequency of maximum interaction between pump and probes to vary along the fiber, thus mitigating the pump pulse depletion and making it possible to use very large probe power, which brings an improved signal-to-noise ratio in detection.

  8. 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%.

  9. Explicit solution for Raman fiber laser using Lambert W function.

    PubMed

    Huang, Chaohong; Cai, Zhiping; Ye, Chenchun; Xu, Huiying

    2007-04-16

    In this paper, an approximate explicit solution for the first-order Raman fiber laser is obtained by using Lambert W function. Good agreement between the explicit solution and numerical simulation is demonstrated. Furthermore, the optimal design of Raman fiber laser is discussed using the proposed solution. The optimal values of fiber length, reflectivity of output fiber Bragg grating and power transfer efficiency are obtained under different pump power. There exists a certain tolerance of the optimal parameters, in which the output power decreases only slightly. The optimal fiber length and reflectivity of output FBG decrease with increasing pump power.

  10. Explicit solution for Raman fiber laser using Lambert W function

    NASA Astrophysics Data System (ADS)

    Huang, Chaohong; Cai, Zhiping; Ye, Chenchun; Xu, Huiying

    2007-04-01

    In this paper, an approximate explicit solution for the first-order Raman fiber laser is obtained by using Lambert W function. Good agreement between the explicit solution and numerical simulation is demonstrated. Furthermore, the optimal design of Raman fiber laser is discussed using the proposed solution. The optimal values of fiber length, reflectivity of output fiber Bragg grating and power transfer efficiency are obtained under different pump power. There exists a certain tolerance of the optimal parameters, in which the output power decreases only slightly. The optimal fiber length and reflectivity of output FBG decrease with increasing pump power.

  11. Output-coupling optimization of Nd-doped fiber lasers.

    PubMed

    Sanchez, F; Meziane, B; Chartier, T; Stephan, G; François, P L

    1995-11-20

    A simple theoretical modeling of the static properties of a fiber laser that includes distributed losses and inhomogeneous pumping is presented. Closed-form expressions for both the output and the backward (at the input mirror) intensities are obtained. The model is based on an extended formulation of the Rigrod's theory. It is shown that the laser responds differently depending on the length of the fiber. In particular, we show that for long (short) lasers optimal output power is achieved with low (high) output-coupler reflectivities. Experimental evidence of these results is obtained with Nd-doped fiber lasers with various lengths.

  12. Coilable Crystalline Fiber (CCF) Lasers and their Scalability

    DTIC Science & Technology

    2014-03-01

    fiber structure. The structure uses undoped YAG as inner cladding and spinel as outer cladding. The design is for laser diode cladding- pumped 2-m...the cladding- pumped Er:YAG/YAG channel waveguide laser . The pumping source, a fiber coupled InGaAsP/InP laser diode module (FCLDM) at 1532 nm, is...fiber lasers , particularly if double-clad to facilitate diode pumping , would improve all these properties so as to enable much shorter length for a

  13. 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.

  14. A cladding-pumped, tunable holmium doped fiber laser.

    PubMed

    Simakov, Nikita; Hemming, Alexander; Clarkson, W Andrew; Haub, John; Carter, Adrian

    2013-11-18

    We present a tunable, high power cladding-pumped holmium doped fiber laser. The laser generated >15 W CW average power across a wavelength range of 2.043 - 2.171 μm, with a maximum output power of 29.7 W at 2.120 μm. The laser also produced 18.2 W when operating at 2.171 µm. To the best of our knowledge this is the highest power operation of a holmium doped laser at a wavelength >2.15 µm. We discuss the significance of background losses and fiber design for achieving efficient operation in holmium doped fibers.

  15. 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.

  16. Aluminum-hollow fiber delivery system for excimer lasers

    NASA Astrophysics Data System (ADS)

    Matsuura, Yuji; Yamamoto, Takashi; Miyagi, Mitsunobu

    2000-05-01

    Hollow fibers for transmitting high-power ArF-excimer laser light are fabricated by Metal Organic Chemical Vapor Deposition method. The hollow fibers with the inner diameter of 1 mm are fabricated by depositing an aluminum film on the inside of silica glass capillary by employing dimethylethylamine alane as the precursor. The fibers shows low-loss property, high durability, and high-energy threshold with the radiation of excimer lasers.

  17. 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.

  18. Gas-Filled Hollow Core Fiber Lasers Based on Population Inversion

    DTIC Science & Technology

    2013-12-05

    iodine (I2) and pumped at ~ 532 nm was studied. Toward improved fiber transmission measurements, novel thulium /holmium fiber laser near 2 microns...transmission, we have demonstrated a novel thulium /holmium fiber laser near 2 microns. Abstract (short): Hollow-core Optical Fiber Gas LASer...measurements, novel thulium /holmium fiber laser near 2 microns were created. H. Schlossberg Hollow-Core Optical Fiber Gas Lasers K. Corwin et al

  19. 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.

  20. 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.

  1. Spontaneous laser-line sweeping in Ho-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Aubrecht, Jan; Peterka, Pavel; Koška, Pavel; Honzátko, Pavel; Jelínek, Michal; Kamrádek, Michal; Frank, Milan; Kubeček, Václav; Kašík, Ivan

    2017-02-01

    Spontaneous laser-line sweeping refers to fiber laser instabilities with regular laser wavelength drift within a broad range that may exceed 10 nm; other characteristics of the laser output are sustained relaxation self-pulsing and narrow spectral linewidth. The laser wavelength drift is caused by standing-wave in the cavity; it can be regarded as a special case of mode instability of longitudinal modes of the laser resonator. Self-sweeping was observed so far in Yb, Er, Tm and Bidoped fiber lasers. We report on Ho-doped fiber laser self-sweeping in interval of 3-5 nm near 2100 nm. The sweeping rate was typically 0.7-0.9 nm/s. The thulium-doped fiber lasers at around 2030 nm and 1950 nm were tested as pump sources. The self-sweeping was registered by FTIR spectrometer and the data processing is discussed.

  2. 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.

  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. Methods and devices based on brillouin selective sideband amplification

    NASA Technical Reports Server (NTRS)

    Yao, X. Steve (Inventor)

    2003-01-01

    Opto-electronic devices and techniques using Brillouin scattering to select a sideband in a modulated optical carrier signal for amplification. Two lasers respectively provide a carrier signal beam and a Brillouin pump beam which are fed into an Brillouin optical medium in opposite directions. The relative frequency separation between the lasers is adjusted to align the frequency of the backscattered Brillouin signal with a desired sideband in the carrier signal to effect a Brillouin gain on the sideband. This effect can be used to implement photonic RF signal mixing and conversion with gain, conversion from phase modulation to amplitude modulation, photonic RF frequency multiplication, optical and RF pulse generation and manipulation, and frequency-locking of lasers.

  5. Incoherent Combining of High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-16

    fiber lasers , IPG Photonics currently holds the record, producing over 3 kW per fiber of single-mode laser ...energy laser systems. The first field demonstration of incoherent beam combining using kilowatt -class, single-mode fiber lasers over a kilometer...combining using kilowatt -class, single-mode fiber lasers . The experiment combined four fiber lasers using a beam director consisting of

  6. 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.

  7. Ultrashort pulsed fiber laser welding and sealing of transparent materials.

    PubMed

    Huang, Huan; Yang, Lih-Mei; Liu, Jian

    2012-05-20

    In this paper, methods of welding and sealing optically transparent materials using an ultrashort pulsed (USP) fiber laser are demonstrated which overcome the limit of small area welding of optical materials. First, the interaction of USP fiber laser radiation inside glass was studied and single line welding results with different laser parameters were investigated. Then multiline scanning was used to obtain successful area bonding. Finally, complete four-edge sealing of fused silica substrates with a USP laser was demonstrated and the hermetic seal was confirmed by water immersion test. This laser microwelding technique can be extended to various applications in the semiconductor industry and precision optic manufacturing.

  8. High-resolution measurement of fiber length by using a mode-locked fiber laser configuration.

    PubMed

    Hu, Y L; Zhan, L; Zhang, Z X; Luo, S Y; Xia, Y X

    2007-06-15

    A simple method to precisely measure fiber length has been experimentally demonstrated by using a mode-locked fiber laser configuration. Since the transit time in a cavity is exactly proportional to the cavity length, it is easy to obtain the fiber length from the generation of mode-locked pulses in the fiber laser with a long-range nonlinear optical loop mirror that includes the measured fiber. Our new method has a large measurement range, over hundreds of kilometers, and a high resolution, of the order of centimeters, as well as no measurement dead zone.

  9. 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.

  10. Wavelength tuning of fiber lasers using multimode interference effects.

    PubMed

    Selvas, R; Torres-Gomez, I; Martinez-Rios, A; Alvarez-Chavez, J; May-Arrioja, D; Likamwa, P; Mehta, A; Johnson, E

    2005-11-14

    We report on a novel scheme to fabricate a simple, cheap, and compact tunable fiber laser. The tuning is realized by splicing a piece of single-mode fiber to one end of an active double-clad fiber, while the other end of the single-mode fiber is spliced to a 15 mm long section of 105/125 multimode fiber. The fluorescence signal entering into the multimode fiber will be reproduced as single images at periodic intervals along the propagation direction of the fiber. The length of the multimode fiber is chosen to be slightly shorter than the first re-imaging point, such that the signal coming out from the single mode fiber is obtained in free space, where a broadband mirror retroreflects the fluorescence signal. Since the position of the re-imaging point is wavelength dependent, different wavelengths will be imaged at different positions. Therefore, wavelength tuning is easily obtained by adjusting the distance between the broadband mirror and the multimode fiber facet end. Using this principle, the tunable fiber laser revealed a tunability of 8 nm, ranging from 1088-1097 nm, and an output power of 500 mW. The simplicity of the setup makes this a very cost-effective tunable fiber laser.

  11. 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.

  12. Enhanced characteristics of fused silica fibers using laser polishing

    NASA Astrophysics Data System (ADS)

    Heptonstall, A.; Barton, M. A.; Bell, A. S.; Bohn, A.; Cagnoli, G.; Cumming, A.; Grant, A.; Gustafson, E.; Hammond, G. D.; Hough, J.; Jones, R.; Kumar, R.; Lee, K.; Martin, I. W.; Robertson, N. A.; Rowan, S.; Strain, K. A.; Tokmakov, K. V.

    2014-05-01

    The search for gravitational wave signals from astrophysical sources has led to the current work to upgrade the two largest of the long-baseline laser interferometers, the LIGO detectors. The first fused silica mirror suspensions for the Advanced LIGO gravitational wave detectors have been installed at the LIGO Hanford and Livingston sites. These quadruple pendulums use synthetic fused silica fibers produced using a CO2 laser pulling machine to reduce thermal noise in the final suspension stage. The suspension thermal noise in Advanced LIGO is predicted to be limited by internal damping in the surface layer of the fibers, damping in the weld regions, and the strength of the fibers. We present here a new method for increasing the fracture strength of fused silica fibers by laser polishing of the stock material from which they are produced. We also show measurements of mechanical loss in laser polished fibers, showing a reduction of 30% in internal damping in the surface layer.

  13. Acoustic emission detection based on distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Yang, Tan; Song, Ying; Zhang, Wen-tao; Li, Fang

    2016-10-01

    Compared with Fiber Bragg grating (FBG), Distributed Feedback fiber laser (DFB-FL) sensors has the advantages of ultra-narrow line-width, high output power, and low noise level, which will result in a better performance in ultra-slight acoustic emission (AE) detection. In this paper, we demonstrate a DFB fiber laser acoustic sensor. The intensity response of DFB-FL to external acoustic waves has been investigated. The frequency response of the DFB fiber laser based AE sensor is measured in aluminum plate. The experiment results show that the intensity modulated DFB fiber laser acoustic sensor can accurately record the continuous acoustic emission signal and the pencil lead-broken acoustic emission waves.

  14. Single-frequency narrow-linewidth Tm-doped fiber laser using silicate glass fiber.

    PubMed

    Geng, Jihong; Wang, Qing; Luo, Tao; Jiang, Shibin; Amzajerdian, Farzin

    2009-11-15

    Single-frequency laser operation near 2 microm has been demonstrated in an all-fiber short-cavity (2-6 cm) distributed feedback laser cavity using both cladding- and core-pump configurations in a newly developed heavily Tm-doped multicomponent silicate glass fiber. Using a single-mode Er-doped fiber laser at 1575 nm as a core-pump source, a 2-cm-long distributed Bragg reflector fiber laser delivers single-frequency output at 1950 nm with laser linewidth less than 3 kHz, which is, to the best of our knowledge, the narrowest linewidth demonstrated to date from any 2 microm single-frequency laser.

  15. 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.

  16. Stimulated Brillouin side-scattering of the beat wave excited by two counter-propagating X-mode lasers in magnetized plasma

    NASA Astrophysics Data System (ADS)

    Verma, Kanika; Sajal, Vivek; Baliyan, Sweta; Kumar, Ravindra; Sharma, Navneet K.

    2015-06-01

    The stimulated Brillouin scattering (SBS) of nonresonant beat mode in the presence of static magnetic field is investigated in a plasma. Two counter-propagating lasers of frequencies ( ω 1 and ω 2 ) and wave vectors ( k 1 and k 2 ) drive a nonresonant space charge beat mode at the phase matching condition of frequency ω 0 ≈ ω 1 ˜ ω 2 and wave number k → 0 ≈ k → 1 + k → 2 . The driver wave parametrically excites a pair of ion acoustic wave ( ω , k → ) and a sideband electromagnetic wave ( ω 3 , k → 3 ) . The beat wave couples with the sideband electromagnetic wave to exert a nonlinear ponderomotive force at the frequency of ion acoustic wave. Density perturbations due to ion acoustic wave and ponderomotive force couple with the oscillatory motion of plasma electron due to velocity of beat wave to give rise to a nonlinear current (by feedback mechanism) responsible for the growth of sideband wave at resonance. The growth rate of SBS was reduced (from ˜ 10 12 s - 1 to 10 10 s - 1 ) by applying a transverse static magnetic field ˜ 90 T. The present study can be useful for the excitation of fast plasma waves (for the purpose of electron acceleration) by two counter-propagating laser beams.

  17. Characterization of novel optical fibers for use in laser detonators

    NASA Astrophysics Data System (ADS)

    Bowden, M. D.; Drake, R. C.; Singleton, C. A.

    2006-08-01

    A system for launching flyers using a Q-switched Nd: YAG laser has been developed for shock initiation of secondary explosives. Flyers have been launched at velocities approaching 6 km s -1. Optical fibers are used to transport the optical energy from the laser to the detonator. The launch of these flyers with sufficient velocity requires a fluence in the region of 35 J cm -2, significantly above the damage threshold of most optical fibers. This damage is typically caused by laser absorption at the input face due to imperfections in the surface polishing. A variety of optical fibers with high quality input faces have been tested at fluences up to 50 J cm -2, and their damage thresholds and beam profiles have been measured. The standard fiber used in this system is a low hydroxyl (-OH) content, 400μm diameter core silica fiber, with CO2 laser polished faces. In addition to this, fibers tapering down to 300μm and 200μm core diameter were investigated, as a means of increasing the efficiency of the system, along with mechanically polished fibers. The fiber currently enters the detonator body from the rear. Depending on the application, it may be required for the fiber to enter from the side. To facilitate this, fibers with a machined output face, designed to produce an output at approximately 90 degrees to the fiber axis were tested. Finally, a 2:1 fiber splitter was tested, as a first step to enable simultaneous firing of several detonators. Multiple initiation points are desirable for applications such as programmable initiation, and it is intended to study fiber splitters with a higher split ratio, such as 4:1 and 8:1. The results of these experiments are presented, and assessments made of suitability for transmission of high-power Qswitched Nd:YAG laser pulses.

  18. Integrated Sagnac loop mirror circuit for fiber laser

    NASA Astrophysics Data System (ADS)

    Lee, Tae Ho; Kim, Chang-Seok; Jeong, Myung Yung

    2007-02-01

    Broadband reflection mirror is an important optical device to make a wide resonance bandwidth of the multi-wavelength fiber laser cavity including fiber Bragg grating mirrors. Though a chirped fiber Bragg grating has been used for broadband reflection mirror device, it still requires more improvements in the control of reflection wavelength bandwidth and reflection ratio, which are key design parameters of broadband reflection mirror. In this research, we propose an integrated mirror circuit based on polarization-maintaining fiber Sagnac loop interferometer to utilize for tunable resonance cavity of fiber laser with semiconductor optical amplifier. It is available to control both resonance bandwidth by varying the length of polarization-maintaining fiber and reflection ratio by tuning the polarization state of Sagnac loop. Broad resonance bandwidth of 40 nm could be obtained from Sagnac mirror with thes 0.15 m length of polarization-maintaining fiber.

  19. Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

    2017-01-01

    The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

  20. Multi-kW cw fiber oscillator pumped by wavelength stabilized fiber coupled diode lasers

    NASA Astrophysics Data System (ADS)

    Becker, Frank; Neumann, Benjamin; Winkelmann, Lutz; Belke, Steffen; Ruppik, Stefan; Hefter, Ulrich; Köhler, Bernd; Wolf, Paul; Biesenbach, Jens

    2013-02-01

    High power Yb doped fiber laser sources are beside CO2- and disk lasers one of the working horses of industrial laser applications. Due to their inherently given robustness, scalability and high efficiency, fiber laser sources are best suited to fulfill the requirements of modern industrial laser applications in terms of power and beam quality. Pumping Yb doped single-mode fiber lasers at 976nm is very efficient. Thus, high power levels can be realized avoiding limiting nonlinear effects like SRS. However the absorption band of Yb doped glass around 976nm is very narrow. Therefore, one has to consider the wavelength shift of the diode lasers used for pumping. The output spectrum of passively cooled diode lasers is mainly defined by the applied current and by the heat sink temperature. Furthermore the overall emission line width of a high power pump source is dominated by the large number of needed diode laser emitters, each producing an individual spectrum. Even though it is possible to operate multi-kW cw single-mode fiber lasers with free running diode laser pumps, wavelength stabilizing techniques for diode lasers (e.g. volume holographic gratings, VHG) can be utilized in future fiber laser sources to increase the output power level while keeping the energy consumption constant. To clarify the benefits of wavelength stabilized diode lasers with integrated VHG for wavelength locking the performance of a dual side pumped fiber oscillator is discussed in this article. For comparison, different pumping configurations consisting of stabilized and free-running diode lasers are presented.

  1. Laser-machined fibers as Fabry-Perot pressure sensors.

    PubMed

    Watson, Stuart; Gander, Matthew J; MacPherson, William N; Barton, James S; Jones, Julian D C; Klotzbuecher, Thomas; Braune, Torsten; Ott, Johannes; Schmitz, Felix

    2006-08-01

    Cavities have been laser ablated in the ends of single-mode optical fibers and sealed by aluminized polycarbonate diaphragms to produce Fabry-Perot pressure sensors. Both conventional fibers and novel, multicore fibers were used, demonstrating the possibility of producing compact arrays of sensors and multiple sensors on an individual fiber 125 microm in diameter. This high spatial resolution can be combined with high temporal resolution by simultaneously interrogating the sensors by using separate laser sources at three wavelengths. Shock tube tests showed a sensor response time of 3 micros to a step increase in pressure.

  2. High power 938 nanometer fiber laser and amplifier

    SciTech Connect

    Dawson, Jay W.; Liao, Zhi Ming; Beach, Raymond J.; Drobshoff, Alexander D.; Payne, Stephen A.; Pennington, Deanna M.; Hackenberg, Wolfgang; Calia, Domenico Bonaccini; Taylor, Luke

    2006-05-02

    An optical fiber amplifier includes a length of silica optical fiber having a core doped with neodymium, a first cladding and a second cladding each with succeeding lower refractive indices, where the first cladding diameter is less than 10 times the diameter of the core. The doping concentration of the neodymium is chosen so that the small signal absorption for 816 nm light traveling within the core is less than 15 dB/m above the other fiber losses. The amplifier is optically pumped with one laser into the fiber core and with another laser into the first cladding.

  3. Statistical properties of partially coherent cw fiber lasers.

    PubMed

    Churkin, Dmitriy V; Smirnov, Sergey V; Podivilov, Evgenii V

    2010-10-01

    We perform a detailed quantitative numerical analysis of a partially coherent quasi-cw fiber laser on the example of a high-Q normal dispersion cavity Raman fiber laser. The key role of precise spectral performances of fiber Bragg gratings forming the laser cavity is clarified. It is shown that cross-phase modulation between the pump and Stokes waves does not affect the generation. Amplitudes of different longitudinal modes strongly fluctuate, obeying the Gaussian distribution. As the intensity statistics is noticeably nonexponential, longitudinal modes should be correlated.

  4. Power scaling of Tm3+ doped ZBLAN blue upconversion fiber lasers: modeling and experiments

    NASA Astrophysics Data System (ADS)

    Qin, G.; Huang, S.; Feng, Y.; Shirakawa, A.; Musha, M.; Ueda, K.-I.

    2006-01-01

    Power scaling of Tm3+ doped ZBLAN blue upconversion fiber lasers was investigated by a simple model. Based on our experimental results on blue fiber lasers, we discuss the effects of photodegradation and photocuring, fiber length, the reflectivity of the coupler mirror and fiber core diameter on further enhancement of blue fiber laser, respectively. The optimal parameters (including fiber length, fiber core diameter and the reflectivity of the coupler mirror) for the operation of high power (>1 W) blue fiber laser were presented through simple numerical simulations, which are valuable for the future design of high power blue upconversion fiber laser.

  5. A novel two-way wavelength division multiplexed fiber laser

    NASA Astrophysics Data System (ADS)

    Ke, Hung-Jen; Chiu, Jian-Lin; Chiang, Chia-Chin; Tsao, Shyh-Lin

    2006-08-01

    We use the fiber loop mirror to form a cavity in our laser system, and two 1.5 μm semiconductor optical amplifier (SOA) also be used as a gain material in the cavity. We analyze the lasing power, SMSR, L-I curve and the stability of our designed symmetric resonator laser with various driving current of the SOA. According to our measured results, we can find that the polarization states of our lasers are stable and the output side-mode suppression ration (SMSR) of our laser is large. We successfully designed a symmetric two-way multi-wavelength wavelength-division-multiplexed (WDM) resonator laser system. The multi-wavelength continuous-wave(CW) fiber laser by utilizing the Fabry-Perot resonance can be applied to PolSK fiber-optic communication systems.

  6. Reflectivity variation in asymmetric random distributed feedback Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Abidin, N. H. Z.; Abu Bakar, M. H.; Tamchek, N.; Mahamd Adikan, F. R.; Mahdi, M. A.

    2016-01-01

    This paper demonstrates and discusses the effect of reflectivity on the intracavity power development and spectral profile of a 41.1 km asymmetric (half-opened cavity) random distributed feedback fiber laser with different pumping schemes. The laser cavity is confined by a fiber Bragg grating and the Rayleigh feedback amplified by Raman scattering effect that serves as virtual random distributed mirrors. The laser performance was observed by integrating a variety of power couplers while employing forward and backward pumping schemes. Forward pumping exhibits greater susceptibility to reflectivity variation compared to backward pumping. Meanwhile, higher reflectivity produced better threshold conditions but at the expense of lower saturation power. A power-saturated laser also manifested a broader spectrum than a laser conducted outside the saturation regime. These research findings will be beneficial in understanding the role of reflectivity and pumping configurations in enhancing asymmetric random distributed feedback fiber laser.

  7. Nd/sup 3 +/-doped cw fiber laser using all-fiber reflectors

    SciTech Connect

    Miller, I.D.; Mortimore, D.B.; Urquhart, P.; Ainslie, B.J.; Craig, S.P.; Miller, C.A.; Payne, D.B.

    1987-06-01

    We demonstrate a novel all-fiber resonant optical cavity which uses two-fiber reflectors, each formed by a single loop of fiber between the output ports of a fiber directional coupler. The reflectivities of the fiber mirrors are each determined by the coupling ratio and the insertion loss of the fused couplers. When the cavity is formed in this way using a continuous length of Nd/sup 3 +/-doped fiber and pumped using a GaAs laser diode, lasing occurs at a wavelength of 1064 nm. Both theoretical and practical descriptions of the device are given.

  8. Continuous-wave laser-induced glass fiber generation

    NASA Astrophysics Data System (ADS)

    Nishioka, Nobuyasu; Hidai, Hirofumi; Matsusaka, Souta; Chiba, Akira; Morita, Noboru

    2017-09-01

    Pulsed-laser-induced glass fiber generation has been reported. We demonstrate a novel glass fiber generation technique by continuous-wave laser illumination and reveal the generation mechanism. In this technique, borosilicate glass, metal foil, and a heat insulator are stacked and clamped by a jig as the sample. Glass fibers are ejected from the side surface of the borosilicate glass by laser illumination of the sample from the borosilicate glass side. SEM observation shows that nanoparticles are attached on the glass fibers. High-speed imaging reveals that small bubbles are formed at the side surface of the borosilicate glass and the bursting of the bubble ejects the fibers. The temperature at the fiber ejection point is estimated to be 1220 K. The mechanism of the fiber ejection includes the following steps: the metal thin foil heated by the laser increases the temperature of the surrounding glass by heat conduction. Since the absorption coefficient of the glass is increased by increasing the temperature, the glass starts to absorb the laser irradiation. The heated glass softens and bubbles form. When the bubble bursts, molten glass and gas inside the bubble scatter into the air to generate the glass fibers.

  9. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Ld-Clad-Pumped All-Fiber Tm3+-Doped Silica Fiber Laser

    NASA Astrophysics Data System (ADS)

    Zhang, Yun-Jun; Song, Shi-Fei; Tian, Yi; Wang, Yue-Zhu

    2009-08-01

    The CW 39.4 W all-fiber LD-clad-pumped Tm3+-doped fiber laser output is reported with a slope efficiency of 34% in respect to the pump power. The all-fiber laser is made up by progressively splicing the pigtail fiber, matched FBG fiber and Tm-doped fiber. The reflective FBG and Tm-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 power output, whereas the total spectrum width is less than 2nm at nearly 1.94 μm.

  10. All fiber-based Yb-doped high energy, high power femtosecond fiber lasers.

    PubMed

    Wan, Peng; Yang, Lih-Mei; Liu, Jian

    2013-12-02

    Two all fiber-based laser systems are demonstrated to achieve high energy and high average power femtosecond pulsed outputs at wavelength of 1 µm. In the high energy laser system, a pulse energy of 1.05 mJ (0.85 mJ after pulse compressor) at 100 kHz repetition rate has been realized by a Yb-doped ultra large-core single-mode photonic crystal fiber (PCF) rod amplifier, seeded with a 50 µJ fiber laser. The pulse duration is 705 fs. In the high average power experiment, a large mode area (LMA) fiber has been used in the final stage amplifier, seeded with a 50 W mode locked fiber laser. The system is running at a repetition rate of 69 MHz producing 1052 W of average power before compressor. After pulse compression, a pulse duration of 800 fs was measured.

  11. Fast low-noise Brillouin spectroscopy measurements of elasticity for corneal crosslinking

    NASA Astrophysics Data System (ADS)

    Bukshtab, Michael; Paranjape, Amit; Friedman, Marc; Muller, David

    2015-03-01

    The Brillouin scattering spectra of biological systems have shown to be inherently related to the intrinsic elasticity and molecular constants of tissues involved. Our approach of combining confocal microscopy and high-resolution Brillouin spectroscopy via a virtual imaging phase array enabled 10-microsecond single-pixel acquisition time without dedicated spatial filtering. Such an approach is adapted via a single-frequency fiber-coupled 780-nm wavelength laser, frequency stabilized by Rb-D2 absorption line, polarization extinction scheme, ASE filtering, heated Rb-vapor Rayleigh-scattering absorbent, and spectroscopic EMCCD camera, unified as CMS-VIPA: confocal virtual-imaging phase array microscopespectrometer. Steady strengthening of corneal bulk modulus was observed via spectral shifts of Brillouin scattering from 5.0-5.2 GHz in untreated porcine eyes to 5.7-5.9 GHz in ones cross-linked in riboflavin plus UV-A light ? at 0.7-0.9 GHz level of enhancement. The cross-linking depths reaching 300-400 microns were measured, as predicted by modeling. A noncontact Brillouin spectroscopic microscopy system for in-vivo corneal elasticity measurement is under development.

  12. The development of novel Ytterbium fiber lasers and their applications

    NASA Astrophysics Data System (ADS)

    Nie, Bai

    The aim of my Ph.D. research is to push the fundamental limits holding back the development of novel Yb fiber lasers with high pulse energy and short pulse duration. The purpose of developing these lasers is to use them for important applications such as multiphoton microscopy and laser-induced breakdown spectroscopy. My first project was to develop a short-pulse high-energy ultrafast fiber laser for multiphoton microscopy. To achieve high multiphoton efficiency and depth resolved tissue imaging, ultrashort pulse duration and high pulse energy are required. In order to achieve this, an all-normal dispersion cavity design was adopted. Output performances of the built lasers were investigated by varying several cavity parameters, such as pump laser power, fiber length and intra-cavity spectral filter bandwidth. It was found that the length of the fiber preceding the gain fiber is critical to the laser performance. Generally, the shorter the fiber is, the broader the output spectrum is. The more interesting parameter is the intra-cavity spectral filter bandwidth. Counter intuitively, laser cavities using narrower bandwidth spectral filters generated much broader spectra. It was also found that fiber lasers with very narrow spectral filters produced laser pulses with parabolic profile, which are referred to as self-similar pulses or similaritons. This type of pulse can avoid wave-breaking and is an optimal approach to generate pulses with high pulse energy and ultrashort pulse duration. With a 3nm intra-cavity spectral filter, output pulses with about 20 nJ pulse energy were produced and compressed to about 41 fs full-width-at-half-maximum (FWHM) pulse duration. Due to the loss in the compression device, the peak power of the compressed pulses is about 250 kW. It was the highest peak power generated from a fiber oscillator when this work was published. This laser was used for multiphoton microscopy on living tissues like Drosophila larva and fruit fly wings. Several

  13. High-power thulium-doped fiber laser in an all-fiber configuration

    NASA Astrophysics Data System (ADS)

    Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

    2016-12-01

    High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

  14. Gratings and fibers for high-power fiber lasers and amplifiers

    NASA Astrophysics Data System (ADS)

    Paye, Corey; Greene, Jon; Rose, Chris

    2003-07-01

    Ytterbium (Tb) doped double-cladding fiber (DCF) lasers and amplifiers are being developed for a number of industrial and military applications. There are several key factors for maximizing the output power of these devices. Lambda Istruments is concentrating on two areas: component development and optical fiber development. The component development effort has focused on grating devices and pump couplers. Stable, highly reflective short-period fiber Bragg gratings are produced in DCF rapidly, have low insertion loss and can be customized for many different laser/amplifier applications. Long-period gratings are also being developed for possible novel use in fiber laser and amplifier applications. A proprietary fiber coupler under development is currently capable of an 85% coupling efficiency. The second focus for Lambda is the development of polarization maintaining Yb-doped DCF. Recent efforts have shifted towards making large mode area versions of these fibers to reduce nonlinear effects at high powers.

  15. Vibrating Optical Fibers to Make Laser Speckle Disappear

    NASA Technical Reports Server (NTRS)

    McGill, Matthew; Scott, V. Stanley

    2005-01-01

    In optical systems in which laser illumination is delivered via multimode optical fibers, laser speckle can be rendered incoherent by a simple but highly effective technique. The need to eliminate speckle arises because speckle can make it difficult to observe edges and other sharp features, thereby making it difficult to perform precision alignment of optical components. The basic ideas of the technique is to vibrate the optical fiber(s) to cause shifting of electromagnetic modes within the fiber(s) and consequent shifting of the speckle pattern in the light emerging from the fiber(s). If the frequency of vibration is high enough, a human eye cannot follow the shifting speckle pattern, so that instead of speckle, a human observer sees a smoothed pattern of light corresponding to a mixture of many electromagnetic modes. If necessary, the optical fiber(s) could be vibrated manually. However, in a typical laboratory situation, it would be more practical to attach a vibrating mechanism to the fiber(s) for routine use as part of the fiber-optic illuminator. In experiments, a commercially available small, gentle, quiet, variable- speed vibratory device was used in this way, with the result that the appearance of speckle was eliminated, as expected. Figures 1 and 2 illustrate the difference.

  16. Modeling compact high power fiber lasers and vecsels

    NASA Astrophysics Data System (ADS)

    Li, Hongbo

    Compact high power fiber lasers and the vertical-external-cavity surface-emitting lasers (VECSELs) are promising candidates for high power laser sources with diffraction-limited beam quality and are currently the subject of intensive research and development. Here three large mode area fiber lasers, namely, the photonic crystal fiber (PCF) laser, the multicore fiber (MCF) laser, and the multimode interference (MMI) fiber laser, as well as the VECSEL are modeled and designed. For the PCF laser, the effective refractive index and the effective core radius of the PCF are investigated using vectorial approaches and reformulated. Then, the classical step-index fiber theory is extended to PCFs, resulting in a highly efficient vectorial effective-index method for the design and analysis of PCFs. The new approach is employed to analyze the modal properties of the PCF lasers with depressed-index cores and to effectively estimate the number of guided modes for PCFs. The MCF laser, consisting of an active MCF and a passive coreless fiber, is modeled using the vectorial mode expansion method developed in this work. The results illustrate that the mode selection in the MCF laser by the coreless fiber section is determined by the MMI effect, not the Talbot effect. Based on the MMI and self-imaging in multimode fibers, the vectorial mode expansion approach is employed to design the first MMI fiber laser demonstrated experimentally. For the design and modeling of VECSELs, the optical, thermal, and structural properties of common material systems are investigated and the most reliable material models are summarized. The nanoscale heat transport theory is applied for the first time, to the best of my knowledge, to design and model VECSELs. In addition, the most accurate strain compensation approach is selected for VECSELs incorporating strained quantum wells to maintain structural stability. The design principles for the VECSEL subcavity are elaborated and applied to design a 1040nm

  17. Linear dissipative soliton in an anomalous-dispersion fiber laser.

    PubMed

    Wang, Ruixin; Dai, Yitang; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong

    2014-12-01

    We report on the generation of linear dissipative soliton (LDS) from an erbium-doped actively mode-locked fiber laser. We show that depending on the down-chirping effect of quadratic phase modulation, instead of the fiber nonlinear Kerr effect in an all-normal-dispersion (ANDi) cavity, stable LDS can be realized in the linear dissipative system. The DS operation of ANDi laser and LDS operation of anomalous dispersion laser are experimentally investigated and compared, and the formation mechanisms of the DS and LDS are discussed. Finally, optical frequency comb generated by the LDS laser is demonstrated.

  18. High-power synchronously pumped femtosecond Raman fiber laser.

    PubMed

    Churin, D; Olson, J; Norwood, R A; Peyghambarian, N; Kieu, K

    2015-06-01

    We report a high-power synchronously pumped femtosecond Raman fiber laser operating in the normal dispersion regime. The Raman laser is pumped by a picosecond Yb(3+)-doped fiber laser. It produces highly chirped pulses with energy up to 18 nJ, average power of 0.76 W and 88% efficiency. The pulse duration is measured to be 147 fs after external compression. We observed two different regimes of operation of the laser: coherent and noise-like regime. Both regimes were experimentally characterized. Numerical simulations are in a good agreement with experimental results.

  19. Optical fiber sensing based on reflection laser spectroscopy.

    PubMed

    Gagliardi, Gianluca; Salza, Mario; Ferraro, Pietro; Chehura, Edmond; Tatam, Ralph P; Gangopadhyay, Tarun K; Ballard, Nicholas; Paz-Soldan, Daniel; Barnes, Jack A; Loock, Hans-Peter; Lam, Timothy T-Y; Chow, Jong H; De Natale, Paolo

    2010-01-01

    An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs) and FBG resonators built in fibers of different types are used for strain, temperature and acceleration measurements using heterodyne-detection and optical frequency-locking techniques. Silica fiber-ring cavities are used for chemical sensing based on evanescent-wave spectroscopy. Various arrangements for signal recovery and noise reduction, as an extension of most typical spectroscopic techniques, are illustrated and results on detection performances are presented.

  20. Small core fiber coupled 60-W laser diode

    NASA Astrophysics Data System (ADS)

    Fernie, Douglas P.; Mannonen, Ilkka; Raven, Anthony L.

    1995-05-01

    Semiconductor laser diodes are compact, efficient and reliable sources of laser light and 25 W fiber coupled systems developed by Diomed have been in clinical use for over three years. For certain applications, particularly in the treatment of benign prostatic hyperplasia and flexible endoscopy, higher powers are desirable. In these applications the use of flexible optical fibers of no more than 600 micrometers core diameter is essential for compatibility with most commercial delivery fibers and instrumentation. A high power 60 W diode laser system for driving these small core fibers has been developed. The design requirements for medical applications are analyzed and system performance and results of use in gastroenterology and urology with small core fibers will be presented.