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Sample records for bandgap fiber laser

  1. Tunable Fabry-Perot filter using hollow-core photonic bandgap fiber and micro-fiber for a narrow-linewidth laser.

    PubMed

    Wang, Xiaozhen; Zhu, Tao; Chen, Liang; Bao, Xiaoyi

    2011-05-01

    A novel tunable fiber Fabry-Perot (FP) filter is proposed and demonstrated by using a hollow-core photonic bandgap fiber (HC-PBF) and a micro-fiber. The interference cavity is a hollow core of HC-PBF. One of the reflection mirrors is the splicing point between a section of HC-PBF and a single mode fiber. The other reflection mirror is a gold-coated end of micro-fiber that uses chemical etching process to obtain the similar diameter as the core of HC-PBF. Hence the movable mirror can be adjusted with long distance inside the hollow core of HC-PBF. Tunable FP filter is used as a mode selecting component in the reflection mode to implement stable single longitudinal mode (SLM) operation in a ring laser. With FP cavity length of 0.25 ± 0.14 mm, the wavelength of SLM laser can be tuned over 1554-1562 nm with a tuning step of 0.2-0.3 nm, a side-mode suppression ratio (SMSR) of 32-36 dB and a linewidth of 3.0-5.1 kHz. With FP cavity length of 2.37 ± 0.37 mm, the SLM laser can be tuned over 1557.3-1560.2 nm with a tuning step of 0.06-0.1 nm, a SMSR of 44-51 dB and a linewidth of 1.8-3.0 kHz. PMID:21643220

  2. High average power, high energy 1.55 μm ultra-short pulse laser beam delivery using large mode area hollow core photonic band-gap fiber.

    PubMed

    Peng, Xiang; Mielke, Michael; Booth, Timothy

    2011-01-17

    We demonstrate high average power, high energy 1.55 μm ultra-short pulse (<1 ps) laser delivery using helium-filled and argon-filled large mode area hollow core photonic band-gap fibers and compare relevant performance parameters. The ultra-short pulse laser beam-with pulse energy higher than 7 μJ and pulse train average power larger than 0.7 W-is output from a 2 m long hollow core fiber with diffraction limited beam quality. We introduce a pulse tuning mechanism of argon-filled hollow core photonic band-gap fiber. We assess the damage threshold of the hollow core photonic band-gap fiber and propose methods to further increase pulse energy and average power handling. PMID:21263632

  3. Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

    SciTech Connect

    England, R. J.; Colby, E. R.; McGuinness, C. M.; Noble, R.; Plettner, T.; Siemann, R. H.; Spencer, J. E.; Walz, D.; Ischebeck, R.; Sears, C. M. S.

    2009-01-22

    An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50 pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. We will describe the experimental plan and recent simulation studies of candidate fibers.

  4. Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

    SciTech Connect

    England, R.J.; Colby, E.R.; Ischebeck, R.; McGuinness, C.M.; Noble, R.; Plettner, T.; Sears, C.M.S.; Siemann, R.H.; Spencer, J.E.; Walz, D.; /SLAC

    2011-11-21

    An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. They will describe the experimental plan and recent simulation studies of candidate fibers.

  5. Calculation of Coupling Efficiencies for Laser-Driven Photonic Bandgap Structures

    SciTech Connect

    England, R. J.; Ng, C.; Noble, R.; Spencer, J. E.

    2010-11-04

    We present a technique for calculating the power coupling efficiency for a laser-driven photonic bandgap structure using electromagnetic finite element simulations, and evaluate the efficiency of several coupling scenarios for the case of a hollow-core photonic bandgap fiber accelerator structure.

  6. Photonic bandgap narrowing in conical hollow core Bragg fibers

    SciTech Connect

    Ozturk, Fahri Emre; Yildirim, Adem; Kanik, Mehmet; Bayindir, Mehmet

    2014-08-18

    We report the photonic bandgap engineering of Bragg fibers by controlling the thickness profile of the fiber during the thermal drawing. Conical hollow core Bragg fibers were produced by thermal drawing under a rapidly alternating load, which was applied by introducing steep changes to the fiber drawing speed. In conventional cylindrical Bragg fibers, light is guided by omnidirectional reflections from interior dielectric mirrors with a single quarter wave stack period. In conical fibers, the diameter reduction introduced a gradient of the quarter wave stack period along the length of the fiber. Therefore, the light guided within the fiber encountered slightly smaller dielectric layer thicknesses at each reflection, resulting in a progressive blueshift of the reflectance spectrum. As the reflectance spectrum shifts, longer wavelengths of the initial bandgap cease to be omnidirectionally reflected and exit through the cladding, which narrows the photonic bandgap. A narrow transmission bandwidth is particularly desirable in hollow waveguide mid-infrared sensing schemes, where broadband light is coupled to the fiber and the analyte vapor is introduced into the hollow core to measure infrared absorption. We carried out sensing simulations using the absorption spectrum of isopropyl alcohol vapor to demonstrate the importance of narrow bandgap fibers in chemical sensing applications.

  7. Broadband optically controlled switching effect in a microfluid-filled photonic bandgap fiber

    NASA Astrophysics Data System (ADS)

    Guo, Junqi; Liu, Yan-ge; Wang, Zhi; Luo, Mingming; Huang, Wei; Han, Tingting; Liu, Xiaoqi

    2016-05-01

    Broadband optically controlled switching in a microfluid-filled photonic bandgap fiber (MF-PBGF) was observed and investigated. The MF-PBGF was formed by infusing a temperature-sensitive high-index fluid into all of the cladding holes of a microstructured optical fiber (MOF). The fiber was then side pumped with a 532 nm continuous wave laser. An extinction ratio of greater than 20 dB at most of the bandgap wavelengths (more than 200 nm) was obtained with a switching power of ∼147 mW. Theoretical and experimental investigations revealed that the effect originated from changes in the temperature gradient induced by heat absorption of the fiber coating with laser illumination. These investigations offer a new and simple approach to achieve wideband and flexible all-optical fiber switching devices without using any photosensitive materials.

  8. Transmission and Propagation of an Accelerating Mode in a Photonic Bandgap Fiber

    SciTech Connect

    Ng, C.-K.; England, R.J.; Lee, L.-Q.; Noble, R.; Rawat, V.; Spencer, J.; /SLAC

    2010-08-26

    A hollow core photonic bandgap (PBG) lattice in a dielectric fiber can provide high gradient acceleration in the optical regime, where the accelerating mode resulting from a defect in the PBG fiber can be excited by high-power lasers. Efficient methods of coupling laser power into the PBG fiber are an area of active research. In this paper, we develop a simulation method using the parallel finite-element electromagnetic suite ACE3P to study the propagation of the accelerating mode in the PBG fiber and determine the radiation pattern into free space at the end of the PBG fiber. The far-field radiation will be calculated and the mechanism of coupling power from an experimental laser setup will be discussed.

  9. Dual-bandgap hollow-core photonic crystal fibers for third harmonic generation.

    PubMed

    Montz, Z; Ishaaya, A A

    2015-01-01

    We present two novel hybrid photonic structures made of silica that possess two well-separated frequency bandgaps. The addition of interstitial air holes in a precise location and size allows these bandgaps to open with a ratio of ∼3 between their central frequencies at the air line ck(z)/w=1, thus fulfilling the basic guidance condition for third harmonic generation in hollow-core fibers. In addition, these designs may serve for high-power laser delivery of two well-separated wavelengths, such as visible and near infrared. PMID:25531607

  10. High-power narrow-linewidth large mode area photonic bandgap fiber amplifier

    NASA Astrophysics Data System (ADS)

    Pulford, Benjamin; Dajani, Iyad; Ehrenreich, Thomas; Holten, Roger; Vergien, Christopher; Naderi, Nader; Mart, Cody; Gu, Guancheng; Kong, Fanting; Hawkins, Thomas; Dong, Liang

    2015-03-01

    Ytterbium-doped large mode area all-solid photonic bandgap fiber amplifiers were used to demonstrate <400 W of output power at 1064 nm. In an initial set of experiments, a fiber with a core diameter of ~50 μm, and a calculated effective area of 1450 μm2 in a straight fiber, was used to generate approximately 600 W. In this case, the input seed was modulated using a sinusoidal format at a frequency of 400 MHz. The output, however, was multimode as the fiber design did not allow for single-mode operation at this wavelength. A second fiber was then fabricated to operate predominantly in single mode at 1064 nm by having the seed closer to the short wavelength edge of the bandgap. This fiber was used to demonstrate 400 W of single-frequency output with excellent beam quality. As the signal power exceeded 450 W, there was significant degradation in the beam quality due to the modal instability. Nevertheless, to the best of our knowledge, the power scaling results obtained in this work far exceed results from prior state of the art all-solid photonic bandgap fiber lasers.

  11. Blue-phase liquid crystal cored optical fiber array with photonic bandgaps and nonlinear transmission properties.

    PubMed

    Khoo, Iam Choon; Hong, Kuan Lung; Zhao, Shuo; Ma, Ding; Lin, Tsung-Hsien

    2013-02-25

    Blue-phase liquid crystal (BPLC) is introduced into the pores of capillary arrays to fabricate fiber arrays. Owing to the photonic-crystals like properties of BPLC, these fiber arrays exhibit temperature dependent photonic bandgaps in the visible spectrum. With the cores maintained in isotropic as well as the Blue phases, the fiber arrays allow high quality image transmission when inserted in the focal plane of a 1x telescope. Nonlinear transmission and optical limiting action on a cw white-light continuum laser is also observed and is attributed to laser induced self-defocusing and propagation modes changing effects caused by some finite absorption of the broadband laser at the short wavelength regime. These nonlinear and other known electro-optical properties of BPLC, in conjunction with their fabrication ease make these fiber arrays highly promising for imaging, electro-optical or all-optical modulation, switching and passive optical limiting applications. PMID:23481965

  12. Thermal tunability of photonic bandgaps in liquid crystal filled polymer photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Wang, Doudou; Chen, Guoxiang; Wang, Lili

    2016-05-01

    A highly tunable bandgap-guiding polymer photonic crystal fiber is designed by infiltrating the cladding air holes with liquid crystal 5CB. Structural parameter dependence and thermal tunability of the photonic bandgaps, mode properties and confinement losses of the designed fiber are investigated. Bandgaps red shift as the temperature goes up. Average thermal tuning sensitivity of 30.9 nm/°C and 20.6 nm/°C is achieved around room temperature for the first and second photonic bandgap, respectively. Our results provide theoretical references for applications of polymer photonic crystal fiber in sensing and tunable fiber-optic devices.

  13. Polarization-maintaining fiber pulse compressor by birefringent hollow-core photonic bandgap fiber.

    PubMed

    Shirakawa, Akira; Tanisho, Motoyuki; Ueda, Ken-Ichi

    2006-12-11

    Structural birefringent properties of a hollow-core photonic-bandgap fiber were carefully investigated and applied to all-fiber chirped-pulse amplification as a compressor. The group birefringence of as high as 6.9x10(-4) and the dispersion splitting by as large as 149 ps/nm/km between the two principal polarization modes were observed at 1557 nm. By launching the amplifier output to one of the polarization modes a 17-dB polarization extinction ratio was obtained without any pulse degradation originating from polarization-mode dispersion. A hybrid fiber stretcher effectively compensates the peculiar dispersion of the photonic-bandgap fiber and pedestal-free 440-fs pulses with a 1-W average power and 21-nJ pulse energy were obtained. Polarization-maintaining fiber-pigtail output of high-power femtosecond pulses is useful for various applications. PMID:19529631

  14. Forward Brillouin scattering in hollow-core photonic bandgap fibers

    NASA Astrophysics Data System (ADS)

    Renninger, W. H.; Shin, H.; Behunin, R. O.; Kharel, P.; Kittlaus, E. A.; Rakich, P. T.

    2016-02-01

    We quantify the strength of stimulated forward Brillouin scattering in hollow-core photonic bandgap fiber through a combination of experiments and multi-physics simulations. Brillouin spectroscopy methods reveal a family of densely spaced Brillouin-active phonon modes below 100 MHz with coupling strengths that approach those of conventional silica fiber. The experimental results are corroborated by multi-physics simulations, revealing that relatively strong optomechanical coupling is mediated by a combination of electrostriction and radiation pressure within the nano-scale silica-air matrix; the nontrivial mechanical properties of this silica-air matrix facilitate the large optomechanical response produced by this system. Simulations also reveal an incredible sensitivity of the Brillouin spectrum to fiber critical dimensions, suggesting opportunity for enhancement or suppression of these interactions. Finally, we relate the measured and calculated couplings to the noise properties of the fiber as the foundation for phase- and polarization-noise estimates in hollow-core fiber. More generally, such Brillouin interactions are an important consideration in both the high and low optical intensity limits.

  15. Fiber distributed feedback laser

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  16. 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.

  17. Extending mode areas of single-mode all-solid photonic bandgap fibers.

    PubMed

    Gu, Guancheng; Kong, Fanting; Hawkins, Thomas W; Jones, Maxwell; Dong, Liang

    2015-04-01

    Mode area scaling of optical fiber is highly desirable for high power fiber laser applications. It is well known that incorporation of additional smaller cores in the cladding can be used to resonantly out-couple higher-order modes from a main core to suppress higher-order-mode propagation in the main core. Using a novel design with multiple coupled smaller cores in the cladding, we have successfully demonstrated a single-mode photonic bandgap fiber with record effective mode area of ~2650µm(2). Detailed numeric studies have been conducted for multiple cladding designs. For the optimal designs, the simulated minimum higher-order-mode losses are well over two orders of magnitudes higher than that of fundamental mode when expressed in dBs. To our knowledge, this is the best higher-order-mode suppression ever found in fibers with this large effective mode areas. We have also experimentally validated one of the designs. M(2)<1.08 across the transmission band was demonstrated. PMID:25968749

  18. Electrically pumped edge-emitting photonic bandgap semiconductor laser

    DOEpatents

    Lin, Shawn-Yu; Zubrzycki, Walter J.

    2004-01-06

    A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.

  19. Applications of Long Period Gratings in Solid Core Photonic Bandgap Fibers

    NASA Astrophysics Data System (ADS)

    Kuhlmey, Boris T.; Luan, Feng; Lazaro, Jose M.; Fu, Libin; Eggleton, Benjamin J.; Yeom, Dong-Il; Coen, Stephane; Wang, Aimin; Knight, Jonathan C.

    2008-10-01

    Solid core photonic bandgap fibres are photonic crystal fibres with a solid core surrounded by high index inclusions. The guidance properties of these fibers are very sensitive to the refractive index of the inclusions, making them widely tunable and making them very promising for sensing applications. Combining these fibers with long period gratings unleashes their full potential, enabling narrow band notch filters tunable over hundreds of nm, refractive index sensors with sensitivity comparable to that of surface plasmon resonance sensors, but also the extraction of the full band diagrams of these bandgap fibres.

  20. Photothermal effect in gas-filled hollow-core photonic bandgap fiber

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Jin, Wei; Cao, Yingchun; Ho, Hoi Lut

    2015-09-01

    We exploit photothermal effect in gas-filled hollow-core photonic bandgap fibers, and demonstrate remarkably sensitive all-fiber (acetylene) gas sensors with noise equivalent concentration of 1-3 parts-per-billion and an unprecedented dynamic range of nearly six orders of magnitude. These results are two to three orders of magnitude better than previous direct absorption-based optical fiber gas sensors. The realization of photothermal spectroscopy in fiber-optic format will allow a new class of sensors with ultra-sensitivity and selectivity, compact size, remote and multiplexed multi-point detection capability.

  1. 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.

  2. Design of Topas photonic bandgap fiber with high birefringence and low confinement loss

    NASA Astrophysics Data System (ADS)

    Wang, Doudou; Wang, Lili

    2010-09-01

    A highly birefringent hollow-core photonic bandgap fiber based on Topas cyclic olefin copolymer is designed. The rhombic hollow-core with rounded corners is formed by omitting four central air holes of the cladding structure. The guided modes, birefringence and confinement loss of the fiber are investigated by using the full-vector finite element method. A high phase birefringence of the order of 10 -3, a group birefringence of the order of 10 -2 and confinement loss less than 0.1 dB/km are obtained at the central wavelength (1.55 μm) range of the bandgap for fiber with seven rings of air holes in the cladding region.

  3. Optical fiber laser

    SciTech Connect

    Snitzer, E.

    1988-10-25

    This patent describes an optical fiber laser comprising: a gain cavity including a single mode optical fiber of given length and index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprising a host material having incorporated therein a predetermined concentration of just erbium oxide having a fluorescence spectrum with a peak emission line at 1.54 micrometers; filter means optically coupled to each end of the fiber gain cavity for providing feedback in the cavity at the peak emission line of the erbium oxide and for permitting energy to be introduced into the cavity at the absorption band of the erbium oxide in the region of 1.45 to 1.53 micrometers; and a laser diode optically coupled to one end of the core for pumping energy into the end of the gain cavity so that the gain cavity oscillates at just the peak emission line.

  4. Semiconductor cylinder fiber laser

    NASA Astrophysics Data System (ADS)

    Sandupatla, Abhinay; Flattery, James; Kornreich, Philipp

    2015-12-01

    We fabricated a fiber laser that uses a thin semiconductor layer surrounding the glass core as the gain medium. This is a completely new type of laser. The In2Te3 semiconductor layer is about 15-nm thick. The fiber laser has a core diameter of 14.2 μm, an outside diameter of 126 μm, and it is 25-mm long. The laser mirrors consist of a thick vacuum-deposited aluminum layer at one end and a thin semitransparent aluminum layer deposited at the other end of the fiber. The laser is pumped from the side with either light from a halogen tungsten incandescent lamp or a blue light emitting diode flash light. Both the In2Te3 gain medium and the aluminum mirrors have a wide bandwidth. Therefore, the output spectrum consists of a pedestal from a wavelength of about 454 to 623 nm with several peaks. There is a main peak at 545 nm. The main peak has an amplitude of 16.5 dB above the noise level of -73 dB.

  5. Pulsed Single Frequency Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Jiang, Shibin

    2016-06-01

    Pulsed single frequency fiber lasers with mJ level near 1 micron, 1.55 micron and 2 micron wavelengths were demonstrated by using our proprietary highly doped fibers. These fiber lasers exhibit excellent long term stable operation with M2<1.2.

  6. 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.

  7. Scattering loss analysis and structure optimization of hollow-core photonic bandgap fiber

    NASA Astrophysics Data System (ADS)

    Song, Jingming; Wu, Rong; Sun, Kang; Xu, Xiaoliang

    2016-06-01

    Effects of core structure in 7 cell hollow-core photonic bandgap fibers (HC-PBGFs) on scattering loss are analyzed by means of investigating normalized interface field intensity. Fibers with different core wall thickness, core radius and rounding corner of air hole are simulated. Results show that with thick core wall and expanded core radius, scattering loss could be greatly reduced. The scattering loss of the HC-PBGFs in the wavelength range of 1.5-1.56 μm could be decreased by about 50 % of the present level with optimized core structure design.

  8. 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.

  9. Investigation on single taper-based all-solid photonic bandgap fiber modal interferometers.

    PubMed

    Li, Jie; Geng, Mengmei; Sun, Li-Peng; Fan, Pengcheng; Liu, Bo; Guan, Bai-Ou

    2016-04-18

    We demonstrate a single taper-based all-solid photonic bandgap (AS-PBG) fiber modal interferometer that consists of a central tapered fiber region connected to the untapered via two abrupt transitions. Modal interference is given by superimposing the bandgap-guided fundamental core mode with a lower effective index and a specific index-guided cladding supermode with a higher effective index. A series of interferometers with taper diameter of 50μm ~60μm and device length of ~3mm are fabricated and studied in contrast to the conventional counterparts. The temperature coefficient of the interferometer is closely determined by the fraction of the cladding supermode energy localized within the index-raised regions of the fiber. The refractive index (RI) responsivities associated to fiber taper sizes are investigated. The measured maximal RI sensitivity is ~3512.36nm/RIU at the taper diameter of 50μm around RI = 1.423. This research gives a deep understanding to the modal-interferometric AS-PBG structure, which we believe to be valuable for the future application of the related device. PMID:27137292

  10. Freedom from band-gap slavery: from diode lasers to quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Capasso, Federico

    2010-02-01

    Semiconductor heterostructure lasers, for which Alferov and Kromer received part of the Nobel Prize in Physics in 2000, are the workhorse of technologies such as optical communications, optical recording, supermarket scanners, laser printers and fax machines. They exhibit high performance in the visible and near infrared and rely for their operation on electrons and holes emitting photons across the semiconductor bandgap. This mechanism turns into a curse at longer wavelengths (mid-infrared) because as the bandgap, shrinks laser operation becomes much more sensitive to temperature, material defects and processing. Quantum Cascade Laser (QCL), invented in 1994, rely on a radically different process for light emission. QCLs are unipolar devices in which electrons undergo transitions between quantum well energy levels and are recycled through many stages emitting a cascade of photons. Thus by suitable tailoring of the layers' thickness, using the same heterostructure material, they can lase across the molecular fingerprint region from 3 to 25 microns and beyond into the far-infrared and submillimiter wave spectrum. High power cw room temperature QCLs and QCLs with large continuous single mode tuning range have found many applications (infrared countermeasures, spectroscopy, trace gas analysis and atmospheric chemistry) and are commercially available. )

  11. Broadband orbital angular momentum transmission using a hollow-core photonic bandgap fiber.

    PubMed

    Li, Haisu; Ren, Guobin; Lian, Yudong; Zhu, Bofeng; Tang, Min; Zhao, Yuanchu; Jian, Shuisheng

    2016-08-01

    We present the viability of exploiting a current hollow-core photonic bandgap fiber (HC-PBGF) to support orbital angular momentum (OAM) states. The photonic bandgap intrinsically provides a large refractive index spacing for guiding light, leading to OAM transmission with low crosstalk. From numerical simulations, a broad OAM±1 mode transmission window with satisfied effective index separations between vector modes (>10-4) and low confinement loss (<3  dB/km) covering 240 nm bandwidth is observed. The OAM purity (defined as normalized power weight for OAM mode) is found to be affected by the modal effective area. Simulation results also show HC-PBGF based OAM transmission is immune to fabrication inaccuracies near the hollow core. This work illustrates that HC-PBGF is a competitive candidate for high-capacity communication harnessing OAM multiplexing. PMID:27472626

  12. Fabrication and characterization of an all-solid tellurite-phosphate photonic bandgap fiber.

    PubMed

    Cheng, Tonglei; Sakai, Yukiko; Suzuki, Takenobu; Ohishi, Yasutake

    2015-05-01

    We present an all-solid tellurite-phosphate photonic bandgap fiber (PBGF) with two layers of high-index rods (TeO2-Li2O-WO3-MoO3-Nb2O5, TLWMN) in the cladding (TeO2-ZnO-Li2O-K2O-Al2O3-P2O5, TZLKAP). TLWMN and TZLKAP glasses have good compatibility for fabricating the all-solid PBGF. Photonic bandgap (PBG) properties are calculated by the plane wave expansion method (PWM), and the results agree well with the measured transmission spectrum. Furthermore, the modal field patterns are measured at ∼1300 and 1520 nm, respectively. The light is confined to the core at ∼1300  nm and lost in the cladding at ∼1520  nm, which match well with the calculated modal field intensities. PMID:25927791

  13. 400-W near diffraction-limited single-frequency all-solid photonic bandgap fiber amplifier.

    PubMed

    Pulford, Benjamin; Ehrenreich, Thomas; Holten, Roger; Kong, Fanting; Hawkins, Thomas W; Dong, Liang; Dajani, Iyad

    2015-05-15

    An ytterbium-doped large-mode area photonic bandgap fiber is used to demonstrate 400 W of single-frequency output at 1064 nm with excellent beam quality and minimal stimulated Brillouin scattering. The fiber possesses all-solid microstructures embedded in the cladding and a core composed of phosphosilicate with a diameter of ∼50  μm. As the signal power is pushed beyond 450 W, there is degradation in the beam quality due to the modal instability. We briefly discuss techniques to alleviate this problem in future designs. To the best of our knowledge, the 400-W single-frequency near diffraction-limited output far exceeds the current state-of-the-art from such type of fiber amplifier. PMID:26393723

  14. Continuous generation of rubidium vapor in hollow-core photonic bandgap fibers.

    PubMed

    Donvalkar, Prathamesh S; Ramelow, Sven; Clemmen, Stéphane; Gaeta, Alexander L

    2015-11-15

    We demonstrate high optical depths (50±5) that last for hours in rubidium-filled hollow-core photonic bandgap fibers, which represent a 1000× improvement over the operation times previously reported. We investigate the vapor generation mechanism using both a continuous wave and a pulsed light source, and find that the mechanism for generating the rubidium atoms is primarily due to thermal vaporization. The continuous generation of large vapor densities should enable measurements at the single-photon level by averaging over longer time scales. PMID:26565879

  15. Novel fiber lasers and applications

    NASA Astrophysics Data System (ADS)

    Zenteno, Luis A.; Walton, Donnell T.

    2003-07-01

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

  16. An investigation of polarization cross-coupling in air-core photonic bandgap fibers

    NASA Astrophysics Data System (ADS)

    Xu, Xiaobin; Song, Ningfang; Zhang, Zhihao; Zhang, Zuchen; Jin, Jing; Zhang, Chunxi

    2016-05-01

    Polarization cross-coupling is one of the most important problems in air-core photonic bandgap fibers (PBF). In this research, polarization cross-coupling is investigated for PBFs of different lengths. The analyzing and simulation results show that the orientation of the birefringent axes induced by residual core ellipticity fluctuates with an average period of ~2.5 cm and random angles uniformly distributed over approximately [-7.5°, 7.5°]. The birefringent orientation in PBF varies much more frequently and strongly than that in any conventional fiber because of the difference in drawing process, and this is the most important factor causing the strong polarization cross-coupling in PBFs.

  17. Backward Secondary-Wave Coherence Errors in Photonic Bandgap Fiber Optic Gyroscopes.

    PubMed

    Xu, Xiaobin; Song, Ningfang; Zhang, Zuchen; Jin, Jing

    2016-01-01

    Photonic bandgap fiber optic gyroscope (PBFOG) is a novel fiber optic gyroscope (FOG) with excellent environment adaptability performance compared to a conventional FOG. In this work we find and investigate the backward secondary-wave coherence (BSC) error, which is a bias error unique to the PBFOG and caused by the interference between back-reflection-induced and backscatter-induced secondary waves. Our theoretical and experimental results show a maximum BSC error of ~4.7°/h for a 300-m PBF coil with a diameter of 10 cm. The BSC error is an important error source contributing to bias instability in the PBFOG and has to be addressed before practical applications of the PBFOG can be implemented. PMID:27338388

  18. Backward Secondary-Wave Coherence Errors in Photonic Bandgap Fiber Optic Gyroscopes

    PubMed Central

    Xu, Xiaobin; Song, Ningfang; Zhang, Zuchen; Jin, Jing

    2016-01-01

    Photonic bandgap fiber optic gyroscope (PBFOG) is a novel fiber optic gyroscope (FOG) with excellent environment adaptability performance compared to a conventional FOG. In this work we find and investigate the backward secondary-wave coherence (BSC) error, which is a bias error unique to the PBFOG and caused by the interference between back-reflection-induced and backscatter-induced secondary waves. Our theoretical and experimental results show a maximum BSC error of ~4.7°/h for a 300-m PBF coil with a diameter of 10 cm. The BSC error is an important error source contributing to bias instability in the PBFOG and has to be addressed before practical applications of the PBFOG can be implemented. PMID:27338388

  19. 503MHz repetition rate femtosecond Yb: fiber ring laser with an integrated WDM collimator.

    PubMed

    Wang, Aimin; Yang, Hongyu; Zhang, Zhigang

    2011-12-01

    We demonstrate 503MHz fundamental high repetition rate operation in a ring cavity passively mode-locked Yb:fiber laser incorporating a novel wavelength-division-multiplexing collimator and a piece of all-solid photonic bandgap fiber. The Yb doped fiber was directly fabricated as one fiber pigtail into the functional collimator, greatly shortening the cavity length and facilitating the splicing operation. A 5cm long photonic bandgap fiber with abnormal dispersion at the lasing wavelength (centered at 1030nm) decreases the net dispersion for shorter output pulses. The spectral bandwidth of the pulse was 34nm. The direct output pulse was measured to be 156fs and the dechirped pulse was about 76fs. With this innovative Yb:fiber pigtailed WDM collimator, the ring cavity laser has the potential to work at a repetition rate up to GHz. PMID:22273932

  20. Infrared detectors and lasers operating in the 3-12 μm range using band-gap engineered structures with type II band-gap alignment

    NASA Astrophysics Data System (ADS)

    Swaminathan, Venkataraman; Little, John W.; Tober, Richard L.

    2006-02-01

    The Type II broken band-gap alignment in semiconductor structures wherein the conduction band minimum is in one semiconductor (e.g., InAs) and the valence band maximum is in another (e.g., GaInSb) offers certain unique advantages which can be utilized to realize band-gap engineered novel quantum electro-optic devices such as lasers and detectors. The advantages of the type II structures include reduced Auger recombination, extending the effective band-gap energy of materials wherein type I band-gap alignment would give rise to difficulties such as miscibility gap. In this paper we describe the work carried out at the Army Research Laboratory on type II semiconductor quantum electro-optic devices such as IR lasers and detectors operating in the 3-12 μm range. Specifically we will cover the progress made in GaSb based type II strained layer superlattice IR detectors and Interband Cascade IR Lasers. We will also present our recent work in self-assembled quantum dots which have type II band-gap alignment with the matrix material in which the dots are embedded.

  1. Detailed theoretical investigation of bending properties in solid-core photonic bandgap fibers.

    PubMed

    Murao, Tadashi; Saitoh, Kunimasa; Koshiba, Masanori

    2009-04-27

    In this paper, detailed properties of bent solid-core photonic bandgap fibers (SC-PBGFs) are investigated. We propose an approximate equivalent straight waveguide (ESW) formulation for photonic bandgap (PBG) edges, which is convenient to see qualitatively which radiation (centripetal or centrifugal radiation) mainly occurs and the impact of bend losses for an operating wavelength. In particular, we show that cladding modes induced by bending cause several complete or incomplete leaky mode couplings with the core mode and the resultant loss peaks. Moreover, we show that the field distributions of the cladding modes are characterized by three distinct types for blue-edge, mid-gap, and red-edge wavelengths in the PBG, which is explained by considering the cladding Bloch states or resonant conditions without bending. Next, we investigate the structural dependence of the bend losses. In particular, we demonstrate the bend-loss dependence on the number of the cladding rings. Finally, by investigating the impacts of the order of PBG and the core structure on the bend losses, we discuss a tight-bending structure. PMID:19399140

  2. Indium Telluride Cylinder Fiber Laser

    NASA Astrophysics Data System (ADS)

    Sandupatla, Abhinay

    A new type of fiber laser is described here. The laser consists of a 25 mm long fiber with an approximately 15 nm thick In2Te3 semiconductor layer at the glass core glass cladding boundary. The laser mirrors consist of a thick vacuum deposited aluminum layer at one end and a thin semitransparent aluminum layer deposited at the other end of the fiber. The laser is pumped from the side with either light from a Halogen Tungsten incandescent lamp or a blue, power LED. Since both, the gain of the In2Te3 semi-conductor and aluminum mirrors have a wide bandwidth the output consists of a pedestal from a wavelength of about 455 nm to about 650 nm with several peaks. There is a main peak at 545 nm. The main peak has an amplitude of 16.5 dB above the noise level of - 73 dB.

  3. 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.

  4. 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.

  5. 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.

  6. Wedged Fibers Suppress Feedback of Laser Beam

    NASA Technical Reports Server (NTRS)

    Ladany, I.

    1986-01-01

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

  7. 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.

  8. High-Power Fiber Lasers Using Photonic Band Gap Materials

    NASA Technical Reports Server (NTRS)

    DiDomenico, Leo; Dowling, Jonathan

    2005-01-01

    at undesirably low levels, and scattering of light from dopants. In designing a given fiber laser for reduced ASE, care must be taken to maintain a correct fiber structure for eventual scaling to an array of many such lasers such that the interactions among all the members of the array would cause them to operate in phase lock. Hence, the problems associated with improving a single-fiber laser are not entirely separate from the bundling problem, and some designs for individual fiber lasers may be better than others if the fibers are to be incorporated into bundles. Extensive calculations, expected to take about a year, must be performed in order to determine design parameters before construction of prototype individual and fiber lasers can begin. The design effort can be expected to include calculations to optimize overlaps between the electromagnetic modes and the gain media and calculations of responses of PBG materials to electromagnetic fields. Design alternatives and physical responses that may be considered include simple PBG fibers with no intensity-dependent responses, PBG fibers with intensity- dependent band-gap shifting (see figure), and broad-band pumping made possible by use of candidate broad-band pumping media in place of the air or vacuum gaps used in prior PBG fibers.

  9. Simultaneous high crystallinity and sub-bandgap optical absorptance in hyperdoped black silicon using nanosecond laser annealing

    SciTech Connect

    Franta, Benjamin Pastor, David; Gandhi, Hemi H.; Aziz, Michael J.; Mazur, Eric; Rekemeyer, Paul H.; Gradečak, Silvija

    2015-12-14

    Hyperdoped black silicon fabricated with femtosecond laser irradiation has attracted interest for applications in infrared photodetectors and intermediate band photovoltaics due to its sub-bandgap optical absorptance and light-trapping surface. However, hyperdoped black silicon typically has an amorphous and polyphasic polycrystalline surface that can interfere with carrier transport, electrical rectification, and intermediate band formation. Past studies have used thermal annealing to obtain high crystallinity in hyperdoped black silicon, but thermal annealing causes a deactivation of the sub-bandgap optical absorptance. In this study, nanosecond laser annealing is used to obtain high crystallinity and remove pressure-induced phases in hyperdoped black silicon while maintaining high sub-bandgap optical absorptance and a light-trapping surface morphology. Furthermore, it is shown that nanosecond laser annealing reactivates the sub-bandgap optical absorptance of hyperdoped black silicon after deactivation by thermal annealing. Thermal annealing and nanosecond laser annealing can be combined in sequence to fabricate hyperdoped black silicon that simultaneously shows high crystallinity, high above-bandgap and sub-bandgap absorptance, and a rectifying electrical homojunction. Such nanosecond laser annealing could potentially be applied to non-equilibrium material systems beyond hyperdoped black silicon.

  10. Simultaneous high crystallinity and sub-bandgap optical absorptance in hyperdoped black silicon using nanosecond laser annealing

    NASA Astrophysics Data System (ADS)

    Franta, Benjamin; Pastor, David; Gandhi, Hemi H.; Rekemeyer, Paul H.; Gradečak, Silvija; Aziz, Michael J.; Mazur, Eric

    2015-12-01

    Hyperdoped black silicon fabricated with femtosecond laser irradiation has attracted interest for applications in infrared photodetectors and intermediate band photovoltaics due to its sub-bandgap optical absorptance and light-trapping surface. However, hyperdoped black silicon typically has an amorphous and polyphasic polycrystalline surface that can interfere with carrier transport, electrical rectification, and intermediate band formation. Past studies have used thermal annealing to obtain high crystallinity in hyperdoped black silicon, but thermal annealing causes a deactivation of the sub-bandgap optical absorptance. In this study, nanosecond laser annealing is used to obtain high crystallinity and remove pressure-induced phases in hyperdoped black silicon while maintaining high sub-bandgap optical absorptance and a light-trapping surface morphology. Furthermore, it is shown that nanosecond laser annealing reactivates the sub-bandgap optical absorptance of hyperdoped black silicon after deactivation by thermal annealing. Thermal annealing and nanosecond laser annealing can be combined in sequence to fabricate hyperdoped black silicon that simultaneously shows high crystallinity, high above-bandgap and sub-bandgap absorptance, and a rectifying electrical homojunction. Such nanosecond laser annealing could potentially be applied to non-equilibrium material systems beyond hyperdoped black silicon.

  11. Optical turbulence in fiber lasers.

    PubMed

    Wabnitz, Stefan

    2014-03-15

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

  12. Plasma-Enhanced Pulsed Laser Deposition of Wide Bandgap Nitrides for Space Power Applications

    NASA Technical Reports Server (NTRS)

    Triplett, G. E., Jr.; Durbin, S. M.

    2004-01-01

    The need for a reliable, inexpensive technology for small-scale space power applications where photovoltaic or chemical battery approaches are not feasible has prompted renewed interest in radioisotope-based energy conversion devices. Although a number of devices have been developed using a variety of semiconductors, the single most limiting factor remains the overall lifetime of the radioisotope battery. Recent advances in growth techniques for ultra-wide bandgap III-nitride semiconductors provide the means to explore a new group of materials with the promise of significant radiation resistance. Additional benefits resulting from the use of ultra-wide bandgap materials include a reduction in leakage current and higher operating voltage without a loss of energy transfer efficiency. This paper describes the development of a novel plasma-enhanced pulsed laser deposition system for the growth of cubic boron nitride semiconducting thin films, which will be used to construct pn junction devices for alphavoltaic applications.

  13. Enhanced chemiluminescent detection scheme for trace vapor sensing in pneumatically-tuned hollow core photonic bandgap fibers.

    PubMed

    Stolyarov, Alexander M; Gumennik, Alexander; McDaniel, William; Shapira, Ofer; Schell, Brent; Sorin, Fabien; Kuriki, Ken; Benoit, Gilles; Rose, Aimee; Joannopoulos, John D; Fink, Yoel

    2012-05-21

    We demonstrate an in-fiber gas phase chemical detection architecture in which a chemiluminescent (CL) reaction is spatially and spectrally matched to the core modes of hollow photonic bandgap (PBG) fibers in order to enhance detection efficiency. A peroxide-sensitive CL material is annularly shaped and centered within the fiber's hollow core, thereby increasing the overlap between the emission intensity and the intensity distribution of the low-loss fiber modes. This configuration improves the sensitivity by 0.9 dB/cm compared to coating the material directly on the inner fiber surface, where coupling to both higher loss core modes and cladding modes is enhanced. By integrating the former configuration with a custom-built optofluidic system designed for concomitant controlled vapor delivery and emission measurement, we achieve a limit-of-detection of 100 parts per billion (ppb) for hydrogen peroxide vapor. The PBG fibers are produced by a new fabrication method whereby external gas pressure is used as a control knob to actively tune the transmission bandgaps through the entire visible range during the thermal drawing process. PMID:22714227

  14. 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).

  15. Controllable Dual-Wavelength Fiber Laser

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  16. Simultaneous monitoring the real and imaginary parts of the analyte refractive index using liquid-core photonic bandgap Bragg fibers.

    PubMed

    Li, Jingwen; Qu, Hang; Skorobogatiy, Maksim

    2015-09-01

    We demonstrate simultaneous monitoring of the real and imaginary parts of the liquid analyte refractive index by using a hollow-core Bragg fiber. We apply this two-channel fiber sensor to monitor concentrations of various commercial cooling oils. The sensor operates using spectral monitoring of the fiber bandgap center wavelength, as well as monitoring of the fiber transmission amplitude at mid-bandgap position. The sensitivity of the fiber sensor to changes in the real part of the core refractive index is found to be 1460nm/Refractive index unit (RIU). By using spectral modality and effective medium theory, we determine the concentrations of the two commercial fluids from the measured refractive indices with an accuracy of ~0.57% for both low- and high-loss oils. Moreover, using an amplitude-based detection modality allows determination of the oil concentration with accuracy of ~1.64% for low-loss oils and ~2.81% for the high-loss oils. PMID:26368402

  17. Multisoliton complexes in fiber lasers

    NASA Astrophysics Data System (ADS)

    Korobko, D. A.; Gumenyuk, R.; Zolotovskii, I. O.; Okhotnikov, O. G.

    2014-12-01

    The formation of stationary and non-stationary pulse groups is regularly observed in multiple pulse soliton fiber lasers. The environment developed in this study for the flexible investigation of this phenomenon is based on the cavity comprising a semiconductor saturable absorber mirror (SESAM) with complex dynamics of absorption recovery and all-fiber dispersion management. The detailed experimental and theoretical considerations show that multiple pulsing in fiber systems offers numerous embodiments ranging from stationary bound states to chaotic bunches. The pulse interaction through the dispersive waves was found to produce a principal impact on the bound state formation. The stability and transformation of stationary bound states and bunch propagation have been also addressed.

  18. 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.

  19. Photonic bandgap crystal resonator enhanced, laser controlled modulations of optical interconnects for photonic integrated circuits.

    PubMed

    Teo, Selin H G; Liu, A Q; Zhang, J B; Hong, M H; Singh, J; Yu, M B; Singh, N; Lo, G Q

    2008-05-26

    Ultrafast high-density photonic integrated circuit devices (PICDs) are not easily obtained using traditional index-guiding mechanisms. In this paper, photonic bandgap crystal resonator enhanced, laser-controlled modulations of optical interconnect PICDs were achieved in slab-type mix-guiding configuration - through developed CMOS-compatible processing technologies. The devices, with smallest critical dimensions of 90 nm have footprints of less than 5 x 5 microm(2). Quality-factors an order larger than previously realized was achieved. Through use of effective coupling structures; simultaneous alignment for probing and pumping laser beams, optical measurements of both instantaneous free carriers induced device modulations were obtained together with thermo-optical effects characterizations. PMID:18545494

  20. 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. PMID:25322245

  1. 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.

  2. Laser doping and metallization of wide bandgap materials: silicon carbide, gallium nitride, and aluminum nitride

    NASA Astrophysics Data System (ADS)

    Salama, Islam Abdel Haleem

    A laser direct write and doping (LDWD) system is designed and utilized for direct metallization and selective area doping in different SiC polytypes, GaN and in dielectrics including AlN. Laser direct metallization in 4H- and 6H-SiC generates metal-like conductive phases that are produced as both rectifying and ohmic contacts without metal deposition. Nd:YAG (lambda = 532, 1064 nm) nanosecond pulsed laser irradiation in SiC induces carbon-rich conductive phases by thermal decomposition of SiC while UV excimer (lambda = 193 nm) laser irradiation produces a silicon-rich phase due to selective carbon photoablation. Linear transmission line method (TLM) pattern is directly fabricated in single crystals SiC by pulsed laser irradiation allowing characterization of the laser fabricated metal-like contacts. Activation of a self focusing effect at the frequency doubled Nd:YAG laser irradiation (lambda = 532 nm) allows to fabricate buried metal like contacts in SiC wafers while maintaining their device-ready surface condition. Gas immersion laser doping (GILD) and laser doping from a molten precursor are utilized to dope both GaN and SiC. Trimethylaluminum (TMAl) and nitrogen are the precursors used to produce p-type and n-type doped SiC; respectively. Nd:YAG and excimer laser nitrogen doping in SiC epilayer and single crystal substrates increases the dopant concentration by two orders of magnitude and produces both deep (500--600 nm) and shallow (50 nm) junctions, respectively. Laser assisted effusion/diffusion is introduced and utilized to dope Al in SiC wafers. Using this technique, a150 nm p-type doped junction is fabricated in semi-insulating 6H- and n-type doped 4H-SiC wafers. Laser-induced p-type doping of Mg in single crystal GaN is conducted using Bis-magnesium dihydrate [Mg(TMHD)2]. Mg concentration and penetration depth up to 10 20--1021 cm-3 and 5mum, respectively are achieved using various laser doping techniques. Laser direct writing and doping (LDWD) is a

  3. Ultraviolet laser quantum well intermixing based prototyping of bandgap tuned heterostructures for the fabrication of superluminescent diodes

    NASA Astrophysics Data System (ADS)

    Beal, Romain; Moumanis, Khalid; Aimez, Vincent; Dubowski, Jan J.

    2016-04-01

    The ultraviolet laser induced quantum well intermixing process has been investigated for prototyping of multiple bandgap quantum well (QW) wafers designed for the fabrication of superluminescent diodes (SLDs). The process takes advantage of a krypton fluoride excimer laser (λ=248 nm) that by irradiating an InP layer capping GaInAs/GaInAsP QW heterostructure leads to the modification of its surface chemical composition and formation of point defects. A subsequent rapid thermal annealing step results in the selective area intermixing of the investigated heterostructures achieving a high quality bandgap tuned material for the fabrication of broad spectrum SLDs. The devices made from a 3-bandgap material are characterized by ~100 nm wide emission spectra with relatively flat profiles and emission exceeding 1 mW.

  4. Optical fiber lasers and amplifiers

    SciTech Connect

    Snitzer, E.; Po, H.; Tumminelli, R.P.; Hakimi, F.

    1989-03-21

    An optical fiber is described, which comprises: a substantially single-mode core having an index of refraction n/sub 1/ comprised of laser material disposed within a multi-mode cladding having an index of refraction n/sub 2/; and a further cladding having an index of refraction n/sub 3/ surrounding the multi-mode cladding with substantially no space between the further cladding and the multi-mode cladding; wherein the single-mode core is disposed at an offset from the geometric center of the multi-mode cladding.

  5. 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).

  6. Fused fiber components for parallel coherent fiber lasers

    NASA Astrophysics Data System (ADS)

    Zoubir, A.; Dupriez, P.

    2015-10-01

    The concept of massively parallel coherent fiber lasers holds great promise to generate enormous laser peak power in order to produce highly energetic particle beams. Such technology is expected to provide a route to practical particle colliders or to proton generation for medical applications. Such concept is based on the phasing of thousands of fiber amplifiers each emitting mJ level pulses, in which optical fibers are key components. In this paper, we present important technological building blocks based on optical fibers, which could pave the way for efficient, compact and cost-effective components to address the technological challenges ahead.

  7. Extreme electronic bandgap modification in laser-crystallized silicon optical fibres.

    PubMed

    Healy, Noel; Mailis, Sakellaris; Bulgakova, Nadezhda M; Sazio, Pier J A; Day, Todd D; Sparks, Justin R; Cheng, Hiu Y; Badding, John V; Peacock, Anna C

    2014-12-01

    For decades now, silicon has been the workhorse of the microelectronics revolution and a key enabler of the information age. Owing to its excellent optical properties in the near- and mid-infrared, silicon is now promising to have a similar impact on photonics. The ability to incorporate both optical and electronic functionality in a single material offers the tantalizing prospect of amplifying, modulating and detecting light within a monolithic platform. However, a direct consequence of silicon's transparency is that it cannot be used to detect light at telecommunications wavelengths. Here, we report on a laser processing technique developed for our silicon fibre technology through which we can modify the electronic band structure of the semiconductor material as it is crystallized. The unique fibre geometry in which the silicon core is confined within a silica cladding allows large anisotropic stresses to be set into the crystalline material so that the size of the bandgap can be engineered. We demonstrate extreme bandgap reductions from 1.11 eV down to 0.59 eV, enabling optical detection out to 2,100 nm. PMID:25262096

  8. Extreme electronic bandgap modification in laser-crystallized silicon optical fibres

    NASA Astrophysics Data System (ADS)

    Healy, Noel; Mailis, Sakellaris; Bulgakova, Nadezhda M.; Sazio, Pier J. A.; Day, Todd D.; Sparks, Justin R.; Cheng, Hiu Y.; Badding, John V.; Peacock, Anna C.

    2014-12-01

    For decades now, silicon has been the workhorse of the microelectronics revolution and a key enabler of the information age. Owing to its excellent optical properties in the near- and mid-infrared, silicon is now promising to have a similar impact on photonics. The ability to incorporate both optical and electronic functionality in a single material offers the tantalizing prospect of amplifying, modulating and detecting light within a monolithic platform. However, a direct consequence of silicon’s transparency is that it cannot be used to detect light at telecommunications wavelengths. Here, we report on a laser processing technique developed for our silicon fibre technology through which we can modify the electronic band structure of the semiconductor material as it is crystallized. The unique fibre geometry in which the silicon core is confined within a silica cladding allows large anisotropic stresses to be set into the crystalline material so that the size of the bandgap can be engineered. We demonstrate extreme bandgap reductions from 1.11 eV down to 0.59 eV, enabling optical detection out to 2,100 nm.

  9. 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.

  10. 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.

  11. Visible upconversion fiber lasers in ring configuration

    NASA Astrophysics Data System (ADS)

    Caspary, Reinhard; Baraniecki, Tomasz P.; Kozak, Marcin M.; Kowalsky, Wolfgang

    2005-09-01

    Up-conversion fiber lasers based on Pr3+/Yb3+ doped fluoride fibers and pumped at 835 nm can operate on emission lines in the red, orange, green, and blue spectral region. Up to now only Fabry-Perot configurations with two mirrors butt-coupled to the fiber ends were investigated. In this paper we present the first visible Pr3+/Yb3+ fiber lasers in a ring configuration. In contrast to the usual Fabry-Perot configuration, the basic ring resonator setup contains no free-space optics and no parts which need to be adjusted. The main challenge for such a setup is the connection between the fluoride laser fiber and the remaining part of the ring resonator, which is made from silica fibers. Due to the very different melting temperatures of both glasses usual fusion splices are impossible. We use a special technique to couple the fibers with glue.

  12. 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.

  13. 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.

  14. 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.

  15. Measurement and suppression of secondary waves caused by high-order modes in a photonic bandgap fiber-optic gyroscope.

    PubMed

    Xu, Xiaobin; Gao, Fuyu; Song, Ningfang; Jin, Jing

    2016-05-16

    Air-core photonic bandgap fiber (PBF) is a good choice for fiber-optic gyroscopes (FOGs) owing to the fact that it can be adapted to a wide variety of environments. However, its multimode properties are disadvantageous for the application to FOGs. An interference-based method is proposed to precisely determine the secondary waves caused by the high-order modes and their coupling. Based on the method, two groups of secondary waves have been found, having optical path differences (OPDs) of ~1.859 m and ~0.85 m, respectively, relative to the primary waves in a PBFOG that consists of a 7-cell PBF coil, approximately 180 m in length. Multi-turn bends of the PBF at both ends of the PBF coil after the fusion splicing points are shown to suppress the intensity of these secondary waves by approximately 10 dB. PMID:27409849

  16. Pulsed laser damage to optical fibers

    SciTech Connect

    Allison, S.W.; Gillies, G.T.; Magnuson, D.W.; Pagano, T.S.

    1985-10-01

    This paper describes some observations of pulsed laser damage to optical fibers with emphasis on a damage mode characterized as a linear fracture along the outer core of a fiber. Damage threshold data are presented which illustrate the effects of the focusing lens, end-surface preparation, and type of fiber. An explanation based on fiber-beam misalignment is given and is illustrated by a simple experiment and ray trace.

  17. In-line Mach-Zehnder interferometer composed of microtaper and long-period grating in all-solid photonic bandgap fiber

    SciTech Connect

    Wu Zhifang; Liu Yange; Wang Zhi; Han Tingting; Li Shuo; Jiang Meng; Ping Shum, Perry

    2012-10-01

    We report a compact in-line Mach-Zehnder interferometer combining a microtaper with a long-period grating (LPG) in a section of all-solid photonic bandgap fiber. Theoretical and experimental investigations reveal that the interferometer works from the interference between the fundamental core mode and the LP{sub 01} cladding supermodes. The mechanism underlying the mode coupling caused by the microtaper can be attributed to a bandgap-shifting as the fiber diameter is abruptly scaled down. In addition, the interferometer designed to strengthen the coupling ratio of the long-period grating has a promising practical application in the simultaneous measurement of curvature and temperature.

  18. Self-tuning fiber lasers

    NASA Astrophysics Data System (ADS)

    Brunton, Steven L.; Kutz, J. N.; Fu, Xing

    2016-03-01

    Advanced methods in data science are driving the characterization and control of nonlinear dynamical systems in optics. In this work, we investigate the use of machine learning, sparsity methods and adaptive control to develop a self-tuning fiber laser, which automatically learns and adapts to maintain high-energy ultrashort pulses. In particular, a two-stage procedure is introduced consisting of a machine learning algorithm to recognize different dynamical regimes with distinct behavior, followed by an adaptive control algorithm to reject disturbances and track optimal solutions despite stochastically varying system parameters. The machine learning algorithm, called sparse representation for classification, comes from machine vision and is typically used for image recognition. The adaptive control algorithm is extremum-seeking control, which has been applied to a wide range of systems in engineering; extremum-seeking is beneficial because of rigorous stability guarantees and ease of implementation.

  19. Dual polarization fiber grating laser hydrophone.

    PubMed

    Guan, Bai-Ou; Tan, Yan-Nan; Tam, Hwa-Yaw

    2009-10-26

    A novel fiber optic hydrophone based on the integration of a dual polarization fiber grating laser and an elastic diaphragm is proposed and experimentally demonstrated. The diaphragm transforms the acoustic pressure into transversal force acting on the laser cavity which changes the fiber birefringence and therefore the beat frequency between the two polarization lines. The proposed hydrophone has advantages of ease of interrogation, absolute frequency encoding, and capability to multiplex a number of sensors on a single fiber by use of frequency division multiplexing technique. PMID:19997174

  20. Temperature dependence of beat-length and confinement loss in an air-core photonic band-gap fiber

    NASA Astrophysics Data System (ADS)

    Xu, Zhenlong; Li, Xuyou; Hong, Yong; Liu, Pan; Yang, Hanrui; Ling, Weiwei

    2016-05-01

    The temperature dependence of polarization-maintaining (PM) property and loss in a highly-birefringent air-core photonic band-gap fiber (PBF) is investigated. The effects of temperature variation on the effective index, beat-length and confinement loss are studied numerically by using the full-vector finite element method (FEM). It is found that, the PM property of this PBF is insensitive to the temperature, and the temperature-dependent beat-length coefficient can be as low as 2.86×10-8 m/°C, which is typically 200 times less than those of conventional panda fibers, the PBF has a stable confinement loss of 0.01 dB/m over the temperature range of -30 to 20 °C for the slow axis at the wavelength of 1.55 μm. The PBF with ultra-low temperature-dependent PM property and low loss can reduce the thermally induced polarization instability apparently in interferometric applications such as resonant fiber optic gyroscope (RFOG), optical fiber sensors, and so on.

  1. 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. PMID:24514624

  2. Advances in fiber combined pump modules for fiber lasers

    NASA Astrophysics Data System (ADS)

    Crum, Trevor; Romero, Oscar; Li, Hanxuan; Jin, Xu; Towe, Terry; Chyr, Irving; Truchan, Tom; Liu, Daming; Cutillas, Serge; Johnson, Kelly; Park, Sang-Ki; Wolak, Ed; Miller, Robert; Bullock, Robert; Mott, Jeff; Fidric, Bernard; Harrison, James

    2009-02-01

    Fiber combining multiple pump sources for fiber lasers has enabled the thermal and reliability advantages of distributed architectures. Recently, mini-bar based modules have been demonstrated which combine the advantages of independent emitter failures previously shown in single-stripe pumps with improved brightness retention yielding over 2 MW/cm2Sr in compact economic modules. In this work multiple fiber-coupled mini-bars are fiber combined to yield an output of over 400 W with a brightness exceeding 1 MW/cm2Sr in an economic, low loss architecture.

  3. 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.

  4. 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.

  5. Visible fiber lasers excited by GaN laser diodes

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  6. Flexible pulse-controlled fiber laser.

    PubMed

    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

  7. 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

  8. 100 Gbit/s WDM transmission at 2 µm: transmission studies in both low-loss hollow core photonic bandgap fiber and solid core fiber.

    PubMed

    Zhang, H; Kavanagh, N; Li, Z; Zhao, J; Ye, N; Chen, Y; Wheeler, N V; Wooler, J P; Hayes, J R; Sandoghchi, S R; Poletti, F; Petrovich, M N; Alam, S U; Phelan, R; O'Carroll, J; Kelly, B; Grüner-Nielsen, L; Richardson, D J; Corbett, B; Garcia Gunning, F C

    2015-02-23

    We show for the first time 100 Gbit/s total capacity at 2 µm waveband, using 4 × 9.3 Gbit/s 4-ASK Fast-OFDM direct modulation and 4 × 15.7 Gbit/s NRZ-OOK external modulation, spanning a 36.3 nm wide wavelength range. WDM transmission was successfully demonstrated over 1.15 km of low-loss hollow core photonic bandgap fiber (HC-PBGF) and over 1 km of solid core fiber (SCF). We conclude that the OSNR penalty associated with the SCF is minimal, while a ~1-2 dB penalty was observed after the HC-PBGF probably due to mode coupling to higher-order modes. PMID:25836529

  9. Amplifier/compressor fiber Raman lasers.

    PubMed

    Islam, M N; Mollenauer, L F; Stolen, R H; Simpson, J R; Shang, H T

    1987-10-01

    We show that the chirp from cross-phase modulation (XPM) dominates the operation of fiber Raman lasers (FRL's). Thus a FRL in the anomalous group-velocity regime is best described as a XPM-chirped Raman amplifier followed by a linear fiber compressor. While the output of such a laser is generally a narrow pulse with a broad pedestal, we show both experimentally and by computer simulation that negligible background is achievable. PMID:19741882

  10. Fiber-Optic Probe For Laser Velocimetry

    NASA Technical Reports Server (NTRS)

    Lynch, Dana H.; Mcalister, Kenneth W.; Gunter, William D., Jr.

    1992-01-01

    Size and weight of optics reduced considerably. Proposed fiber-optic probe in laser velocimeter smaller (and, therefore, lighter in weight and more maneuverable) than previous probe. Proposed configuration is product of calculations and experiments showing virtual waists serve same purpose. Laser-velocimeter lens brought close to transfer lenses to focus on virtual waists, thereby shortening probe head considerably.

  11. Excimer laser machining of optical fiber taps

    NASA Astrophysics Data System (ADS)

    Coyle, Richard J.; Serafino, Anthony J.; Grimes, Gary J.; Bortolini, James R.

    1991-05-01

    Precision openings for construction of an optical backplane have been machined in an optical fiber using an excimer laser operating at a wavelength of 193 nm. The openings were made by imaging the laser beam onto the polymer fiber cladding with a telescope, then ablating the cladding with a sufficient number of pulses to expose the core. Circular openings measuring 250 and 625 microns and elliptical openings measuring 650 X 350 microns have been made in the cladding of a 1 mm polymer-clad silica fiber. Examination by scanning electron microscopy reveals that the best quality openings are obtained with either the smaller circular geometry or the elliptical geometry. For various reasons, elliptical openings, with the major axis oriented along the longitudinal axis of the fiber, appear more suitable for tap construction. Individual optical fiber taps have been constructed by attaching a tap fiber to a laser machined opening in a central fiber using an ultraviolet-curable acralate. Individual tap measurements were made on the elliptical and the 250 micron circular openings. In addition, a triple tap assembly was made using elliptical tap openings. These results indicate that the excimer laser machining technique may be applicable to the construction of a linear tapped bus for optical backplanes.

  12. Actively mode-locked Raman fiber laser.

    PubMed

    Yang, Xuezong; Zhang, Lei; Jiang, Huawei; Fan, Tingwei; Feng, Yan

    2015-07-27

    Active mode-locking of Raman fiber laser is experimentally investigated for the first time. An all fiber connected and polarization maintaining loop cavity of ~500 m long is pumped by a linearly polarized 1120 nm Yb fiber laser and modulated by an acousto-optic modulator. Stable 2 ns width pulse train at 1178 nm is obtained with modulator opening time of > 50 ns. At higher power, pulses become longer, and second order Raman Stokes could take place, which however can be suppressed by adjusting the open time and modulation frequency. Transient pulse evolution measurement confirms the absence of relaxation oscillation in Raman fiber laser. Tuning of repetition rate from 392 kHz to 31.37 MHz is obtained with harmonic mode locking. PMID:26367642

  13. Fiber optic mounted laser driven flyer plates

    SciTech Connect

    Paisley, D.L.

    1990-12-31

    This invention is comprised of a laser driven flyer plate where the flyer plate is deposited directly onto the squared end of an optical fiber. The plasma generated by a laser pulse drives the flyer plate toward a target. In another embodiment, a first metal layer is deposited onto the squared end of an optical fiber, followed by a layer of a dielectric material and a second metal layer. The laser pulse generates a plasma in the first metal layer, but the plasma is kept away from the second metal layer by the dielectric layer until the pressure reaches the point where shearing occurs. 2 figs.

  14. Bidirectional pumped high power Raman fiber laser.

    PubMed

    Xiao, Q; Yan, P; Li, D; Sun, J; Wang, X; Huang, Y; Gong, M

    2016-03-21

    This paper presents a 3.89 kW 1123 nm Raman all-fiber laser with an overall optical-to-optical efficiency of 70.9%. The system consists of a single-wavelength (1070nm) seed and one-stage bidirectional 976 nm non-wavelength-stabilized laser diodes (LDs) pumped Yb-doped fiber amplifier. The unique part of this system is the application of non-wavelength-stabilized LDs in high power bidirectional pumping configuration fiber amplifier via refractive index valley fiber combiners. This approach not only increases the pump power, but also shortens the length of fiber by avoiding the usage of multi-stage amplifier. Through both theoretical research and experiment, the bidirectional pumping configuration presented in this paper proves to be able to convert 976 nm pump laser to 1070 nm laser via Yb3+ transfer, which is then converted into 1123 nm Raman laser via the first-order Raman effect without the appearance of any higher-order Raman laser. PMID:27136862

  15. 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

    2016-06-01

    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.

  16. 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.

  17. Black anneal marking with pulsed fiber lasers

    NASA Astrophysics Data System (ADS)

    Murphy, T.; Harrison, P.; Norman, S.

    2015-07-01

    High contrast marking of metals is used in a wide range of industries. Fiber laser marking of these metals provides non-contact marking with no consumables, offering many advantages over traditional methods of metal marking. The laser creates a permanent mark on the material surface combining heat and oxygen with no noticeable ablation. The focussed beam of the fiber laser in combination with precision control of the heat input is able to treat small areas of the material surface evenly and consistently, which is critical for producing black anneal marks. The marks are highly legible which is ideal for marking serial numbers or small data matrices where traceability is required. This paper reports the experimental study for producing black anneal marks on various grades of stainless steel using fiber lasers. The influence of metal surface finish, beam quality, spot size diameter and pulse duration are investigated for producing both smooth and decorative anneal marks.

  18. Fiber Delivery of mid-IR lasers

    SciTech Connect

    Kriesel, J.M.; Gat, N.; Bernacki, Bruce E.; Myers, Tanya L.; Bledt, Carlos M.; Harrington, James P.

    2011-08-24

    Fiber optics for the visible to near infrared (NIR) wavelength regimes (i.e. = 0.42 {mu}m) have proven to be extremely useful for a myriad of applications such as telecommunications, illumination, and sensors because they enable convenient, compact, and remote delivery of laser beams. Similarly, there is a need for fiber optics operating at longer wavelengths. For example, systems operating in the mid-IR regime (i.e., = 314 {mu}m) are being developed to detect trace molecular species with far-reaching applications, such as detecting explosives on surfaces, pollutants in the environment, and biomarkers in the breath of a patient. Furthermore, with the increasing availability of quantum cascade lasers (QCLs) which are semiconductor lasers that operate in the mid-IR regime additional uses are rapidly being developed. Here, we describe the development of hollow-core fibers for delivery of high-quality mid-IR laser beams across a broad spectral range.

  19. Low-light-level nonlinear optics with rubidium atoms in hollow-core photonic band-gap fibers

    NASA Astrophysics Data System (ADS)

    Bhagwat, Amar Ramdas

    Low-light-level optical nonlinearities are of significant interest for performing operations such as single-photon switching and quantum non-demolition measurements on single-photons. To evoke strong nonlinearities from single-photons, one can enhance the matter-photon interaction using strongly nonlinear materials such as alkali vapors in combination with an appropriate geometry such as a waveguide, which provides a long interaction length while maintaining a small light mode area. We demonstrate for the first time that such a system can be experimentally realized by loading rubidium vapor inside a hollow-core photonic band-gap fiber. Using the technique of light-induced atomic desorption in this geometry, we have generated optical depths greater than 1000. As a proof of principle, we demonstrate electromagnetically induced transparency (EIT) with control powers 1000 times lower than those used for hot vapor cells in a focused beam geometry. Working with such a high aspect ratio geometry requires us to identify and measure the various sources of decoherence via spectroscopy of desorbed atoms in the fiber. Using such techniques, we also estimate the temperature of the desorbing atoms inside the fiber. The desorption mechanism is studied, and we show that pulsed desorption beams of the right amplitude and duration can be used for generating precisely controlled optical depths. Finally, we investigate the use of various buffer gas techniques for increasing the effective transverse path of the atoms as they move across the fiber in order to reduce their ground state decoherence and map this effect as a function of buffer gas pressure.

  20. Laser jamming technique research based on combined fiber laser

    NASA Astrophysics Data System (ADS)

    Jie, Xu; Shanghong, Zhao; Rui, Hou; Shengbao, Zhan; Lei, Shi; Jili, Wu; Shaoqiang, Fang; Yongjun, Li

    2009-06-01

    A compact and light laser jamming source is needed to increase the flexibility of laser jamming technique. A novel laser jamming source based on combined fiber lasers is proposed. Preliminary experimental results show that power levels in excess of 10 kW could be achieved. An example of laser jamming used for an air-to-air missile is given. It shows that the tracking system could complete tracking in only 4 s and came into a steady state with its new tracking target being the laser jamming source.

  1. 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.

  2. 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).

  3. 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).

  4. The crucial fiber components and gain fiber for high power ytterbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Liao, Lei; Liu, Peng; Xing, Ying-Bin; Wang, Yi-Bo; Dai, Neng-Li; Li, Jin-Yan; He, Bing; Zhou, Jun

    2015-08-01

    We have demonstrated a kW continuous-wave ytterbium-doped all-fiber laser oscillator with 7×1 fused fiber bundle combiner, fiber Bragg grating (FBG) and double-clad gain fiber fabricated by corresponding technologies. The results of experiment that the oscillator had operated at 1079.48nm with 80.94% slope efficiency without the influence of temperature and non-linear effects indicate that fiber components and gain fiber were suitable to high power environment. No evidence of the signal power roll-over showed that this oscillator possess the capacity to highest output with available pump power.

  5. 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

  6. Carbon Dioxide Laser Fiber Optics In Endoscopy

    NASA Astrophysics Data System (ADS)

    Fuller, Terry A.

    1982-12-01

    Carbon dioxide laser surgery has been limited to a great extent to surgical application on the integument and accessible cavities such as the cervix, vagina, oral cavities, etc. This limitation has been due to the rigid delivery systems available to all carbon dioxide lasers. Articulating arms (series of hollow tubes connected by articulating mirrors) have provided an effective means of delivery of laser energy to the patient as long as the lesion was within the direct line of sight. Even direct line-of-sight applications were restricted to physical dimension of the articulating arm or associated hand probes, manipulators and hollow tubes. The many attempts at providing straight endoscopic systems to the laser only stressed the need for a fiber optic capable of carrying the carbon dioxide laser wavelength. Rectangular and circular hollow metal waveguides, hollow dielectric waveguides have proven ineffective to the stringent requirements of a flexible surgical delivery system. One large diameter (1 cm) fiber optic delivery system, incorporates a toxic thalliumAbased fiber optic material. The device is an effective alternative to an articulating arm for external or conventional laser surgery, but is too large and stiff to use as a flexible endoscopic tool. The author describes the first highly flexible inexpensive series of fiber optic systems suitable for either conventional or endoscopic carbon dioxide laser surgery. One system (IRFLEX 3) has been manufactured by Medlase, Inc. for surgical uses capable of delivering 2000w, 100 mJ pulsed energy and 15w continuous wave. The system diameter is 0.035 inches in diameter. Surgically suitable fibers as small as 120 um have been manufactured. Other fibers (IRFLEX 142,447) have a variety of transmission characteristics, bend radii, etc.

  7. Bandgap engineering of InGaAsP/InP laser structure by photo-absorption-induced point defects

    NASA Astrophysics Data System (ADS)

    Kaleem, Mohammad; Nazir, Sajid; Saqib, Nazar Abbas

    2016-03-01

    Integration of photonic components on the same photonic wafer permits future optical communication systems to be dense and advanced performance. This enables very fast information handling between photonic active components interconnected through passive optical low loss channels. We demonstrate the UV-Laser based Quantum Well Intermixing (QWI) procedure to engineer the band-gap of compressively strained InGaAsP/InP Quantum Well (QW) laser material. We achieved around 135nm of blue-shift by simply applying excimer laser (λ= 248nm). The under observation laser processed material also exhibits higher photoluminescence (PL) intensity. Encouraging experimental results indicate that this simple technique has the potential to produce photonic integrated devices and circuits.

  8. 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.

  9. Cascade Raman soliton fiber ring laser

    SciTech Connect

    Gouveia-Neto, A.S.; Gomes, A.S.L.; Taylor, J.R.; Ainslie, B.J.; Craig, S.P.

    1987-11-01

    Pulses as short as 200 fsec at 1.5 ..mu..m and 230 fsec at 1.6 ..mu..m have been generated through a cascade Raman, solitonlike process in a fiber ring oscillator. A dispersion-shifted (lambda/sub 0/ = 1.46 ..mu..m) single-mode fiber was used as the gain medium, which was synchronously pumped by a cw mode-locked Nd:YAG laser operated at 1.32 ..mu..m.

  10. Fiber laser vector hydrophone: theory and experiment

    NASA Astrophysics Data System (ADS)

    Zhang, Wentao; Zhang, Faxiang; Ma, Rui; He, Jun; Li, Fang; Liu, Yuliang

    2011-05-01

    A novel fiber laser vector hydrophone (FLVH) based on accelerometers is presented. Three fiber laser accelerometers (FLA), perpendicular to each other, are used to detect the acoustic induced particle acceleration. Theoretical analyses of the acoustic sensitivity and the natural frequency are given. Experiment shows a sensitivity of 0.1 pm/Pa@100 Hz is achieved, which results in a minimum detectable acoustic signal of 100 μPa/@Hz@100 Hz. Field demonstration shows that the proposed vector hydrophone has good directivity.

  11. Innovations in high power fiber laser applications

    NASA Astrophysics Data System (ADS)

    Beyer, Eckhard; Mahrle, Achim; Lütke, Matthias; Standfuss, Jens; Brückner, Frank

    2012-02-01

    Diffraction-limited high power lasers represent a new generation of lasers for materials processing, characteristic traits of which are: smaller, cost-effective and processing "on the fly". Of utmost importance is the high beam quality of fiber lasers which enables us to reduce the size of the focusing head incl. scanning mirrors. The excellent beam quality of the fiber laser offers a lot of new applications. In the field of remote cutting and welding the beam quality is the key parameter. By reducing the size of the focusing head including the scanning mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. By using these frequencies very thin and deep welding seams can be generated experienced so far with electron beam welding only. The excellent beam quality of the fiber laser offers a high potential for developing new applications from deep penetration welding to high speed cutting. Highly dynamic cutting systems with maximum speeds up to 300 m/min and accelerations up to 4 g reduce the cutting time for cutting complex 2D parts. However, due to the inertia of such systems the effective cutting speed is reduced in real applications. This is especially true if complex shapes or contours are cut. With the introduction of scanner-based remote cutting systems in the kilowatt range, the effective cutting speed on the contour can be dramatically increased. The presentation explains remote cutting of metal foils and sheets using high brightness single mode fiber lasers. The presentation will also show the effect of optical feedback during cutting and welding with the fiber laser, how those feedbacks could be reduced and how they have to be used to optimize the cutting or welding process.

  12. All-fiber normal-dispersion femtosecond laser

    PubMed Central

    Kieu, K.; Wise, F. W.

    2011-01-01

    Spectral filtering of a chirped pulse can be a strong pulse-shaping mechanism in all-normal-dispersion femtosecond fiber lasers. We report an implementation of such a laser that employs only fiber-format components. The Yb-doped fiber laser includes a fiber filter, and a saturable absorber based on carbon nanotubes. The laser generates 1.5-ps, 3-nJ pulses that can be dechirped to 250 fs duration outside the cavity. PMID:18648465

  13. Modeling loss and backscattering in a photonic-bandgap fiber using strong perturbation

    NASA Astrophysics Data System (ADS)

    Zamani Aghaie, Kiarash; Digonnet, Michel J. F.; Fan, Shanhui

    2013-02-01

    We use coupled-mode theory with strong perturbation to model the loss and backscattering coefficients of a commercial hollow-core fiber (NKT Photonics' HC-1550-02 fiber) induced by the frozen-in longitudinal perturbations of the fiber cross section. Strong perturbation is used, for the first time to the best of our knowledge, because the large difference between the refractive indices of the two fiber materials (silica and air) makes conventional weak-perturbation less accurate. We first study the loss and backscattering using the mathematical description of conventional surface-capillary waves (SCWs). This model implicitly assumes that the mechanical waves on the core wall of a PBF have the same power spectral density (PSD) as the waves that develop on an infinitely thick cylindrical tube with the same diameter as the PBF core. The loss and backscattering coefficients predicted with this thick-wall SCW roughness are 0.5 dB/km and 1.1×10-10 mm-1, respectively. These values are more than one order of magnitude smaller than the measured values (20-30 dB/km and ~1.5×10-9 mm-1, respectively). This result suggests that the thick-wall SCW PSD is not representative of the roughness of our fiber. We found that this discrepancy occurs at least in part because the effect of the finite thickness of the silica membranes (only ~120 nm) is neglected. We present a new expression for the PSD that takes into account this finite thickness and demonstrates that the finite thickness substantially increases the roughness. The predicted loss and backscattering coefficients predicted with this thin-film SCW PSD are 30 dB/km and 1.3×10-9 mm-1, which are both close to the measured values. We also show that the thin-film SCW PSD accurately predicts the roughness PSD measured by others in a solid-core photonic-crystal fiber.

  14. 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.

  15. Coiled Fiber Pulsed Laser Simulator

    Energy Science and Technology Software Center (ESTSC)

    2009-01-29

    This suite of codes simulates the transient output pulse from an optically-pumped coiled fiber amplifier. The input pulse is assumed to have a Gaussian time dependence and a spatial dependence that may be Gaussian or an eigenmode of the straight of bent fiber computed using bend10 or bend20. Only one field component is used (semivectorial approximation). The fully-spatially-dependent fiber gain profile is specified is subroutines "inversion" and "interp_inversion" and is presently read from a datamore » file, although other means of specifying fiber gain could be reallized through modification of these subroutines. The input pulse is propagated through the fiber, including the following physical effects: spatial and temporal gain saturation, self-focusing, bend losses, and confinement from a user-defined fiber index profile. The user can follow the propagation progress with 3D graphics that show an intensity profile via user-modifiable cutting planes through the time space axes. A restart capability is also included. Approximate solutions in the frequency domain may be obtained much faster using the auxilliary codes bendbpm10 (full vector), bendbpm20 (semivectoral), and bendbpm21 (semivectoral with gain sheet spproximation for gain and self-focusing). These codes all include bend loss and spatial (but not temporal) gain saturation.« less

  16. Coiled Fiber Pulsed Laser Simulator

    SciTech Connect

    Hadley, G. Ronald

    2009-01-29

    This suite of codes simulates the transient output pulse from an optically-pumped coiled fiber amplifier. The input pulse is assumed to have a Gaussian time dependence and a spatial dependence that may be Gaussian or an eigenmode of the straight of bent fiber computed using bend10 or bend20. Only one field component is used (semivectorial approximation). The fully-spatially-dependent fiber gain profile is specified is subroutines "inversion" and "interp_inversion" and is presently read from a data file, although other means of specifying fiber gain could be reallized through modification of these subroutines. The input pulse is propagated through the fiber, including the following physical effects: spatial and temporal gain saturation, self-focusing, bend losses, and confinement from a user-defined fiber index profile. The user can follow the propagation progress with 3D graphics that show an intensity profile via user-modifiable cutting planes through the time space axes. A restart capability is also included. Approximate solutions in the frequency domain may be obtained much faster using the auxilliary codes bendbpm10 (full vector), bendbpm20 (semivectoral), and bendbpm21 (semivectoral with gain sheet spproximation for gain and self-focusing). These codes all include bend loss and spatial (but not temporal) gain saturation.

  17. AFIRE: fiber Raman laser for laser guide star adaptive optics

    NASA Astrophysics Data System (ADS)

    Bonaccini Calia, D.; Hackenberg, W.; Chernikov, S.; Feng, Y.; Taylor, L.

    2006-06-01

    Future adaptive optics systems will benefit from multiple sodium laser guide stars in achieving satisfactory sky coverage in combination with uniform and high-Strehl correction over a large field of view. For this purpose ESO is developing with industry AFIRE, a turn-key, rack-mounted 589-nm laser source based on a fiber Raman laser. The fiber laser will deliver the beam directly at the projector telescope. The required output power is in the order of 10 W in air per sodium laser guide star, in a diffraction-limited beam and with a bandwidth of < 2 GHz. This paper presents the design and first demonstration results obtained with the AFIRE breadboard. 4.2W CW at 589nm have so far been achieved with a ~20% SHG conversion efficiency.

  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. Hybrid fiber-rod laser

    SciTech Connect

    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.

  20. Temperature assisted band-gap engineering in all-solid chalcogenide holey fiber for mid-IR application

    NASA Astrophysics Data System (ADS)

    Barh, Ajanta; Varshney, R. K.; Pal, B. P.; Sanghera, J.; Shaw, L. B.

    2015-06-01

    Presence of photonic band-gap (PBG) in an all-solid microstructured optical fiber (MOF), made of two fabrication compatible chalcogenide (Ch) glasses is theoretically investigated for potential application in the functional mid-infrared (IR) wavelength range. Cross-section of the MOF is formed by assuming periodically arranged wavelength scale circular air holes in a hexagonal pattern embedded in a uniform matrix. One type of Ch-glass is considered as the background material whereas another type of Ch-glass is assumed to fill the air holes. The relative index contrast between these two Ch-glasses is ~ 24%, for which PBG appears only for a suitable range of non-zero longitudinal wave vector. We have studied the scalability of this PBG by varying the lattice parameter of MOF and optimized the cross-section to attain the PBG at ~ 2 μm wavelength. Then by utilizing the thermo-optic properties of the glasses, the effect of external temperature (T) on the PBG is studied, and finally we have proposed a T-tunable wavelength filter/sensor at mid-IR wavelength with tuning sensitivity as high as ~ 140 pm/°C.

  1. 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

  2. Graphene Q-switched, tunable fiber laser

    NASA Astrophysics Data System (ADS)

    Popa, D.; Sun, Z.; Hasan, T.; Torrisi, F.; Wang, F.; Ferrari, A. C.

    2011-02-01

    We demonstrate a wideband-tunable Q-switched fiber laser exploiting a graphene saturable absorber. We get ˜2 μs pulses, tunable between 1522 and 1555 nm with up to ˜40 nJ energy. This is a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics.

  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. Dynamic pulsing of a MOPA fiber laser

    NASA Astrophysics Data System (ADS)

    Romero, Rosa; Guerreiro, Paulo T.; Hendow, Sami T.; Salcedo, José R.

    2011-05-01

    Dynamic Pulsing is demonstrated using a pulsed MOPA fiber laser at 1064nm. The output of the MOPA laser is a pulsed profile consisting of a burst of closely spaced pulses. Tests were performed under several materials with pulse bursts ranging from 10ns to 1μs and operating from 500kHz down to single shot. In particular, percussion drilling in stainless steel is demonstrated showing improvements in quality and speed of the process. These profiles allow high flexibility and optimization of the process addressing the specificity of the end application. Dynamic Pulsing allows the same MOPA fiber laser to be used in diverse materials as well as different processes such us marking, drilling, scribing and engraving. The pulsed fiber laser used in this study is a MOPA-DY by Multiwave Photonics. It is based on a modulated seed laser followed by a series of fiber amplifiers and ending with an optically isolated collimator. This pulsed laser model has an output in such a way that each trigger produces a fast burst of pulses, with a repetition frequency within the burst of the order of tens of MHz. Within the burst it is possible to change the number of pulses, the individual pulse profile, burst pulse period and even to generate non-periodic burst pulse separations. The laser allows full freedom for all these combinations. The study here reported compares the impact of pulse peak power, number of pulses within a burst and the pulse burst period, on process quality (heat affected zone, debris, hole uniformity) and drilling yield.

  5. Optical fiber laser of multifrequency emission

    NASA Astrophysics Data System (ADS)

    Beltrán-Pérez, Georgina; Jacobo Aispuro, Liliana; Lucian Rocha, Froylan; Castillo Mixcóatl, Juan; Múñoz Aguirre, Severino

    2007-03-01

    The wavelength division multiplexor (WDM) has a great importance in the technology of the communications by optical fiber, is an economic and efficient form, to increase the capacity of transmission by several orders of magnitude, reason why it is desirable to have laser sources of multiple wavelengths in a system WDM, which, according to reported works, have been obtained using diverse types of filters. In this work we presented a laser of multifrequency emission, of Erbium doped optical fiber, tuned with an optical fiber filter. The configuration of the optical filter, presents high stability and low lost by insertion, independence to the changes of polarization, low powers of light entrance, and has an useful spectral wide. It has the advantage to have a simple design and easy manufacture in addition to his low losses.

  6. Laser Cutting of Carbon Fiber Fabrics

    NASA Astrophysics Data System (ADS)

    Fuchs, A. N.; Schoeberl, M.; Tremmer, J.; Zaeh, M. F.

    Due to their high weight-specific mechanical stiffness and strength, parts made from carbon fiber reinforced polymers (CFRP) are increasingly used as structural components in the aircraft and automotive industry. However, the cutting of preforms, as with most automated manufacturing processes for CFRP components, has not yet been fully optimized. This paper discusses laser cutting, an alternative method to the mechanical cutting of preforms. Experiments with remote laser cutting and gas assisted laser cutting were carried out in order to identify achievable machining speeds. The advantages of the two different processes as well as their fitness for use in mass production are discussed.

  7. High sensitivity high temperature sensor based on SMS structure with large-core all-solid bandgap fiber as the multimode section

    NASA Astrophysics Data System (ADS)

    Franco, Marcos A. R.; Cruz, Alice L. S.; Serrão, Valdir A.; Barbosa, Carmem L.

    2014-05-01

    A fiber optic interferometric device based on a singlemode-multimode-singlemode (SMS) structure is proposed as a high sensitive high temperature sensor. The multimode section (MMF) consists of a large-core all-solid photonic bandgap fiber (AS-PBF) with silica as the background material and germanium-doped silica at the high index regions. The numerical analyses were carried out by beam propagation method. The numerical results indicate a constant high temperature sensitivity of ~-35 pm/°C over a large temperature range from 20oC to 930°C.

  8. High-power fiber laser studies at the Polaroid Corporation

    NASA Astrophysics Data System (ADS)

    Muendel, Martin H.

    1998-06-01

    Current work on the Polaroid double-clad fiber laser is discussed. Experiments towards testing the upper power limits of fiber lasers are described. Models for the laser output in the rate-equation approximation, for the laser polarization state, and for the axial-mode-beating noise are presented and compared to experiment.

  9. Tapered fiber based high power random laser.

    PubMed

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

    2016-04-18

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

  10. 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.

  11. Use of hollow core fibers, fiber lasers, and photonic crystal fibers for spark delivery and laser ignition in gases

    SciTech Connect

    Joshi, Sachin; Yalin, Azer P.; Galvanauskas, Almantas

    2007-07-01

    The fiber-optic delivery of sparks in gases is challenging as the output beam must be refocused to high intensity ({approx}200 GW/cm2 for nanosecond pulses). Analysis suggests the use of coated hollow core fibers, fiber lasers, and photonic crystal fibers (PCFs). We study the effects of launch conditions and bending for 2 m long coated hollow fibers and find an optimum launch f of {approx}55 allowing spark formation with {approx}98% reliability for bends up to a radius of curvature of 1.5 m in atmospheric pressure air. Spark formation using the output of a pulsed fiber laser is described, and delivery of 0.55 mJ pulses through PCFs is shown.

  12. Direct laser writing of three-dimensional narrow bandgap and high refractive-index PbSe structures in a solution.

    PubMed

    Gan, Zongsong; Cao, Yaoyu; Gu, Min

    2013-05-01

    Three-dimensional (3D) micro/nano structures made of narrow electronic bandgap semiconductor materials have important applications in a wide range of disciplines. Direct laser writing (DLW) provides the unparalleled advantage to fabricate 3D arbitrary geometric structures at the micro and nano meter scale. The fabrication of 3D structures within bulk narrow electronic bandgap semiconductor materials by DLW is challenged for the top-down strategy due to their narrow bandgap and high refractive index. Here, we report on the bottom-up strategy for the fabrication of 3D micro/nano structures made from PbSe with an electronic bandgap as narrow as 0.27 eV and a refractive index as high as 4.82 in a solution. PMID:23669977

  13. 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.

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

    PubMed

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

    2016-01-01

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

  15. All-fiber single-mode PM thulium fiber lasers using femtosecond laser written fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Willis, Christina C. C.; Bradford, Joshua D.; Sims, R. Andrew; Shah, Lawrence; Richardson, Martin; Thomas, Jens; Becker, Ria G.; Voigtländer, Christian; Tünnermann, Andreas; Nolte, Stefan

    2011-02-01

    A polarization-maintaining (PM), narrow-linewidth, continuous wave, thulium fiber laser is demonstrated. The laser cavity is formed from two femtosecond-laser-written fiber Bragg gratings (FBGs) and operates at 2054 nm. The laser output possesses both narrow spectral width (78 pm) and a high polarization extinction ratio of ~18 dB at 5.24 W of output power. This laser is a unique demonstration of a PM thulium fiber system based on a two FBG cavity that produces high PER without any free-space elements. Such a narrow linewidth source will be useful for applications such as spectral beam combining which often employ polarization dependent combining elements.

  16. 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

  17. 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.

  18. Novel optical fiber ultrasonic sensor based on fiber laser

    NASA Astrophysics Data System (ADS)

    Wu, Qi; Okabe, Yoji; Sun, Junqiang

    2014-03-01

    Researching high-sensitivity flexible ultrasonic sensor is important in the field of structural health monitoring (SHM). In this research, a novel ultrasonic sensor based on fiber ring laser with an in-built phase shifted fiber Bragg grating (PSFBG) is proposed and demonstrated. The first function of the PS-FBG is to determine the wavelength of the laser. Thus, this sensing system is robust to temperature change and quasi-static strain change because the PS-FBG is always illuminated. The other function of the PS-FBG is a sensor with ultra-steep slope and short effective grating length. It is beneficial for achievement of high-sensitivity and broad-bandwidth ultrasonic detection. The experimental evaluated sensitivity was 58.5+/-3 dB, which is 7.5 dB higher than traditional PZT sensor. This may be the highest sensitivity obtained by optical fiber sensing system. Because of the advantages including robustness, simple structure and low cost in addition to the high sensitivity and broad bandwidth, this sensing system has potential practical applications in ultrasonic SHM.

  19. 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.

  20. Precise balancing of viscous and radiation forces on a particle in liquid-filled photonic bandgap fiber.

    PubMed

    Euser, T G; Garbos, M K; Chen, J S Y; Russell, P St J

    2009-12-01

    A great challenge in microfluidics is the precise control of laser radiation forces acting on single particles or cells, while allowing monitoring of their optical and chemical properties. We show that, in the liquid-filled hollow core of a single-mode photonic crystal fiber, a micrometer-sized particle can be held stably against a fluidic counterflow using radiation pressure and can be moved to and fro (over tens of centimeters) by ramping the laser power up and down. Accurate studies of the microfluidic drag forces become possible, because the particle is trapped in the center of the single guided optical mode, resulting in highly reproducible radiation forces. The counterflowing liquid can be loaded with sequences of chemicals in precisely controlled concentrations and doses, making possible studies of single particles, vesicles, or cells. PMID:19953158

  1. 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. PMID:23869163

  2. 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

  3. 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.

  4. Fiber amplifiers and lasers in Yb:silica

    SciTech Connect

    Wilcox, R.B.; Browning, D.F.; Feit, M.D.; Nyman, B.

    1996-11-15

    We have measured gain and saturation in sing;e mode Yb:silica fiber, and developed fiber lasers and amplifiers at 1053 nm. The lasers are tunable over 10`s of nanometers, with amplifier gain flattened by fiber gratings or dielectric filters.

  5. 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.

  6. Blackening of metals using femtosecond fiber laser.

    PubMed

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

    2015-01-10

    This study presents an unprecedented high throughput processing for super-blackening and superhydrophobic/hydrophilic surface on both planar and nonplanar metals surfaces. By using a high pulse repetition rate femtosecond (fs) fiber laser, a light trapping microstructure and nanostructure is generated to absorb light from UV, visible to long-wave infrared spectral region. Different types of surface structures are produced with varying laser scanning conditions (scanning speed and pitch). The modified surface morphologies are characterized using scanning electron microscope and the blackening effect is investigated through spectral measurements. Spectral measurements show that the reflectance of the processed materials decreases sharply in a wide wavelength range and the decrease occurs at different rates for different scanning pitches and speeds. Above 98% absorption over the entire visible wavelength region and above 95% absorption over the near-infrared, middle-wave infrared and long-wave infrared regions range has been demonstrated for the surface structures, and the absorption for specific wavelengths can go above 99%. Furthermore, the processing efficiency of this fs fiber laser blackening technique is 1 order of magnitude higher than that of solid-state fs laser and 4 times higher than that of picosecond (ps) laser. Further increasing of the throughput is expected by using higher repetition and higher scanning speed. This technology offers the great potential in applications such as constructing sensitive detectors and sensors, solar energy absorber, and biomedicine. PMID:25967633

  7. 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.

  8. 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.

  9. 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.

  10. Theory of a random fiber laser

    NASA Astrophysics Data System (ADS)

    Kolokolov, I. V.; Lebedev, V. V.; Podivilov, E. V.; Vergeles, S. S.

    2014-12-01

    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.

  11. 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.

  12. 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.

  13. Yb- and Er-doped fiber laser Q-switched with an optically uniform, broadband WS2 saturable absorber

    PubMed Central

    Zhang, M.; Hu, Guohua; Hu, Guoqing; Howe, R. C. T.; Chen, L.; Zheng, Z.; Hasan, T.

    2015-01-01

    We demonstrate a ytterbium (Yb) and an erbium (Er)-doped fiber laser Q-switched by a solution processed, optically uniform, few-layer tungsten disulfide saturable absorber (WS2-SA). Nonlinear optical absorption of the WS2-SA in the sub-bandgap region, attributed to the edge-induced states, is characterized by 3.1% and 4.9% modulation depths with 1.38 and 3.83 MW/cm2 saturation intensities at 1030 and 1558 nm, respectively. By integrating the optically uniform WS2-SA in the Yb- and Er-doped laser cavities, we obtain self-starting Q-switched pulses with microsecond duration and kilohertz repetition rates at 1030 and 1558 nm. Our work demonstrates broadband sub-bandgap saturable absorption of a single, solution processed WS2-SA, providing new potential efficacy for WS2 in ultrafast photonic applications. PMID:26657601

  14. 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.

  15. Fiber Bragg grating in large-mode-area fiber for high power fiber laser applications.

    PubMed

    Mohammed, Waleed; Gu, Xijia

    2010-10-01

    Fiber Bragg gratings (FBGs) are indispensable components in the design of monolithic high-power fiber lasers. As the laser power scales up, the adoption of larger-mode-area fibers with high V numbers poses new challenges for FBG design and fabrication. In this paper, we present the simulation, fabrication, and measurement of the FBGs inscribed on large-mode-area fibers. The simulation used the T-matrix approach to calculate the spectral response of the FBG that matched well with the measured spectra. The observed fringes in the reflection spectrum are explained by the interference between the low-order modes that were also confirmed with the simulation. Some unique features of the FBG and their potential applications are discussed. PMID:20885465

  16. 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.

  17. Thulium fiber laser damage to the ureter

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2015-07-01

    Our laboratory is studying experimental thulium fiber laser (TFL) as a potential alternative lithotripter to the clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium laser-induced damage to ureter tissue have been previously reported. Similarly, this study characterizes TFL induced ureter and stone basket damage. A TFL beam with pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rates of 150-500 Hz was delivered through a 100-μm-core, low-OH, silica optical fiber to the porcine ureter wall, in vitro. Ureter perforation times were measured and gross, histological, and optical coherence tomography images of the ablation zone were acquired. TFL operation at 150, 300, and 500 Hz produced mean ureter perforation times of 7.9, 3.8, and 1.8 s, respectively. Collateral damage averaged 510, 370, and 310 μm. TFL mean perforation time exceeded 1 s at each setting, which is a greater safety margin than previously reported during Holmium laser ureter perforation studies.

  18. A random Q-switched fiber laser.

    PubMed

    Tang, Yulong; Xu, Jianqiu

    2015-01-01

    Extensive studies have been performed on random lasers in which multiple-scattering feedback is used to generate coherent emission. Q-switching and mode-locking are well-known routes for achieving high peak power output in conventional lasers. However, in random lasers, the ubiquitous random cavities that are formed by multiple scattering inhibit energy storage, making Q-switching impossible. In this paper, widespread Rayleigh scattering arising from the intrinsic micro-scale refractive-index irregularities of fiber cores is used to form random cavities along the fiber. The Q-factor of the cavity is rapidly increased by stimulated Brillouin scattering just after the spontaneous emission is enhanced by random cavity resonances, resulting in random Q-switched pulses with high brightness and high peak power. This report is the first observation of high-brightness random Q-switched laser emission and is expected to stimulate new areas of scientific research and applications, including encryption, remote three-dimensional random imaging and the simulation of stellar lasing. PMID:25797520

  19. 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.

  20. Tunable Q-switched fiber laser based on saturable edge-state absorption in few-layer molybdenum disulfide (MoS₂).

    PubMed

    Woodward, R I; Kelleher, E J R; Howe, R C T; Hu, G; Torrisi, F; Hasan, T; Popov, S V; Taylor, J R

    2014-12-15

    We fabricate a few-layer molybdenum disulfide (MoS₂) polymer composite saturable absorber by liquid-phase exfoliation, and use this to passively Q-switch an ytterbium-doped fiber laser, tunable from 1030 to 1070 nm. Self-starting Q-switching generates 2.88 μs pulses at 74 kHz repetition rate, with over 100 nJ pulse energy. We propose a mechanism, based on edge states within the bandgap, responsible for the wideband nonlinear optical absorption exhibited by our few-layer MoS₂ sample, despite operating at photon energies lower than the material bandgap. PMID:25607060

  1. Short pulse dynamics in a linear cavity fiber laser

    NASA Astrophysics Data System (ADS)

    Razukov, Vadim A.; Melnikov, Leonid A.

    2016-04-01

    New suitable numerical scheme is proposed for simulation of dynamics of oppositely running pulses in a fiber laser with linear cavity. The proposed model allows to include various temporal and spatial effects which affect the laser dynamics. The pulse evolution in the fiber cavity with perfect reflectors at the fiber ends with accounting of fiber group velocity dispersion and self-phase modulation is demonstrated.

  2. Laser beam application with high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Beyer, Eckhard; Brenner, Berndt; Morgenthal, Lothar

    2007-05-01

    With the new industrial high power fiber lasers we have already stepped into a new generation of laser applications. These lasers are smaller, better, more cost-effective, and offer a processing "on the fly." Of utmost importance is their excellent beam quality which enables us to reduce the size of the focussing head including the scanning mirrors. With the reduced mass of the mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. Using such mirrors with this high beam quality we can shape the key hole geometry, and thus it is possible to decrease the keyhole spiking, which always occur in the case of deep penetration welding. We can generate very thin and deep welding seams, which we have only experienced with electron beam welding. The excellent beam quality of the fiber lasers offers us a lot of new applications from deep penetration welding to high speed welding. By using beam scanning we are able to easily change the beam and the seam geometry. Furthermore, it is possible to work with this kind of laser from a distance of some meters between focussing/scanning head and the work piece. This technique is called remote processing or processing "on the fly." The excellent beam quality also enables us to cut very precisely, and due to the small cutting widths with a very high speed. In this case the main problem is that the roughness of the cutting edge increases a little bit. One reason for this is that we cannot blow out the mold as easily as we can do it with higher cutting widths. There are also polarized fiber lasers on the market where we can use the Brewster effect for different applications. The presentation will cover some physical basics including different industrial applications.

  3. Dispersion measurements of mode-locked fiber laser components

    NASA Astrophysics Data System (ADS)

    Louthain, James A.; Hayduk, Michael J.; Erdmann, Reinhard K.

    2000-07-01

    Precise control of the dispersion within mode-locked laser cavities can lead to optical pulse compression and reduced timing jitter of mode-locked lasers. Two simple measurement techniques are used to provide a complete picture of the dispersion within an erbium doped mode-locked fiber laser cavity. We measured the optical dispersion of erbium-doped fiber, standard single mode fiber, and chirped Bragg gratings. We built a Michelson interferometer with a wideband LED source to measure the dispersion of fiber lengths of less than 1 meter. Next, we measured the dispersion of chirped Bragg gratings using a network analyzer and a tunable laser in a differential phase measurement technique.

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

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas Clifton

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

  5. Powerful 2-μm all-fiber laser sources pumped by Raman fiber lasers

    NASA Astrophysics Data System (ADS)

    Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Jin, Xiaoxi; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-11-01

    We present novel and powerful pump schemes for fiber laser sources operating near 2 μm, which employing high power Raman fiber lasers (RFLs) to provide sufficient pump light. Firstly, we demonstrate a Tm-doped fiber laser (TDFL) pumped by two RFLs at 1173 nm. The output power of the TDFL reached 96 W with slope efficiency of 0.42, and the central wavelength located at 1943.3 nm. This is the first TDFL with 100 W-level output power pumped by RFLs around Tm3+ ions' ~1200 nm absorption band. Secondly, we demonstrate a Ho-doped fiber laser (HDFL) employing a 1150 nm RFL as pump source. The 1150 nm RFL provided 110 W pump power and the output power of the HDFL reached 42 W with slope efficiency of 0.37. The lasing wavelength covered from 2046.8 nm to 2049.5 nm with optical signal-to-noise ratio more than 30 dB. This is the first HDFL pumped by a 1150 nm RFL and the highest output power achieved at this pump band. In the last, we present a high power Ho-doped fiber (HDF) superfluorescent source (SS) pumped by a 1150 nm RFL. The SS's output power reached 1.5 W, and the full width at half maximum was about 30 nm. This is the highest output power achieved in HDF as far as we know. The results above indicate promising and powerful pump schemes to achieve higher power output in fiber lasers near 2 μm, which also can be further improved by optimizing the parameters of the sources.

  6. Evaluation of specialty fibers and waveguides for ultrashort laser pulse propagation

    NASA Astrophysics Data System (ADS)

    Nguyen, Michael N.

    Ultrashort pulse lasers have become invaluable tools in many areas of science and technology. Optical waveguide or fiber delivery of ultrashort pulses would benefit numerous applications that require remote location of the laser or for addressing areas of low accessibility such as minimally invasive surgical procedures, multiphoton excitation microscopy, laser micromachining and high bandwidth telecommunications. However, the extremely high peak power and bandwidth associated with ultrashort pulses are prohibitive for most conventional waveguides that guide light in solid dielectric cores, the main drawbacks being dispersion, nonlinear effects, and damage via optical breakdown. The purpose of this study is to investigate the significant obstacles involved with implementing optical waveguides or fibers capable of delivering ultrashort pulses. In recent years, specialty fibers such as large mode-area (LMA) photonic crystal and photonic bandgap fibers have been developed, which exhibit remarkable properties such as single-mode guidance that is independent of core size and guidance in an air core respectively. In this thesis, two early prototypes of each of these fibers are investigated for their ability to deliver ultrashort pulses. Another specialty fiber, silver coated hollow silica waveguide, which was originally developed for delivery of infrared light from CO2 and Er:YAG lasers is shown to be a good candidate for single-mode delivery of gigawatt peak power pulses with minimal pulse distortion. Another potential fiber is comprised of multiple evanescently-coupled single-mode cores. This so-called multi-core fiber has demonstrated increased power handling in fiber lasers and amplifiers and was selected as a candidate for delivery of ultrashort pulses due to its scalable large mode-area and increased nonlinear threshold. A design for multi-core fibers is proposed that allows tailoring of the supermode distribution to obtain equal power distribution among all cores

  7. Property and Shape Modulation of Carbon Fibers Using Lasers.

    PubMed

    Blaker, Jonny J; Anthony, David B; Tang, Guang; Shamsuddin, Siti-Ros; Kalinka, Gerhard; Weinrich, Malte; Abdolvand, Amin; Shaffer, Milo S P; Bismarck, Alexander

    2016-06-29

    An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes. PMID:27227575

  8. Diode-Pumped Dye Laser Using a Tapered Optical Fiber

    NASA Astrophysics Data System (ADS)

    Patterson, Brian; Stofel, James; Myers, Elliot; Knize, Randy

    2015-05-01

    We describe the construction of a simple dye laser based on a single-mode optical fiber. Light from a 120-mW laser diode (λ = 520 nm) is launched into the fiber. The fiber is tapered to a diameter of approximately 1 μm and placed in Rhodamine 6G laser dye. The pump light interacts with the gain medium through the evanescent field outside the fiber causing stimulated emission, which couples back into the fiber. Mirrors on each end of the fiber provide the necessary feedback for lasing, and a grating is used to narrow the spectral output. We characterize the lasing threshold and output spectrum of the laser. This has been a good project for undergraduate students to learn about lasers and optics.

  9. 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.

  10. Fiber laser front end for high energy petawatt laser systems

    SciTech Connect

    Dawson, J W; Messerly, M J; Phan, H; Mitchell, S; Drobshoff, A; Beach, R J; Siders, C; Lucianetti, A; Crane, J K; Barty, C J

    2006-06-15

    We are developing a fiber laser front end suitable for high energy petawatt laser systems on large glass lasers such as NIF. The front end includes generation of the pulses in a fiber mode-locked oscillator, amplification and pulse cleaning, stretching of the pulses to >3ns, dispersion trimming, timing, fiber transport of the pulses to the main laser bay and amplification of the pulses to an injection energy of 150 {micro}J. We will discuss current status of our work including data from packaged components. Design detail such as how the system addresses pulse contrast, dispersion trimming and pulse width adjustment and impact of B-integral on the pulse amplification will be discussed. A schematic of the fiber laser system we are constructing is shown in figure 1 below. A 40MHz packaged mode-locked fiber oscillator produces {approx}1nJ pulses which are phase locked to a 10MHz reference clock. These pulses are down selected to 100kHz and then amplified while still compressed. The amplified compressed pulses are sent through a non-linear polarization rotation based pulse cleaner to remove background amplified spontaneous emission (ASE). The pulses are then stretched by a chirped fiber Bragg grating (CFBG) and then sent through a splitter. The splitter splits the signal into two beams. (From this point we follow only one beam as the other follows an identical path.) The pulses are sent through a pulse tweaker that trims dispersion imbalances between the final large optics compressor and the CFBG. The pulse tweaker also permits the dispersion of the system to be adjusted for the purpose of controlling the final pulse width. Fine scale timing between the two beam lines can also be adjusted in the tweaker. A large mode area photonic crystal single polarization fiber is used to transport the pulses from the master oscillator room to the main laser bay. The pulses are then amplified a two stage fiber amplifier to 150mJ. These pulses are then launched into the main amplifier

  11. Ultra thin fiber laser vector hydrophone

    NASA Astrophysics Data System (ADS)

    Ma, Rui; Zhang, Wentao; He, Jun; Li, Fang; Liu, Yuliang

    2011-05-01

    This paper presents a two-axis fiber laser vector hydrophone which uses a V-shaped flexed beam to enhance the sensitivity and reduce the dimensions. Theoretical analyses of the sensitivity and frequent response are given. The key parameters that determine the sensitivity and resonant frequency are discussed. The experimental results show an acceleration sensitivity of 39.2 pm/g and 53.2 pm/g at the x, y axis respectively, a resonant frequency of about 310 Hz, and a directivity resolution larger than 20 dB.

  12. Hybrid femtosecond fiber laser outcrossing Er-doped fiber and Yb-doped fiber

    NASA Astrophysics Data System (ADS)

    Kim, Yunseok; Park, Sanguk; Kim, Seung-Woo

    2014-07-01

    A hybridized scheme of a fiber femtosecond pulse laser was devised with the aim of grafting the frequency comb of an Er-doped fiber oscillator, stabilized around a 1.550 μm center wavelength, onto the 1.0 μm emission range of an Yb-doped fiber amplifier. Test results showed that the frequency comb is successfully transferred to a new 1.034 μm center wavelength with a spectral bandwidth of 21 nm, upholding an original frequency stability of 3.71 × 10-13 at 10 s averaging. This work demonstrates the feasibility of outcrossing different kinds of fibers to shift the spectral range of the frequency comb over a large operating span without loss of stability.

  13. Femtosecond fiber laser welding of dissimilar metals.

    PubMed

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

    2014-10-01

    In this paper, welding of dissimilar metals was demonstrated for the first time, to the best of our knowledge, by using a high-energy high-repetition-rate femtosecond fiber laser. Metallurgical and mechanical properties were investigated and analyzed under various processing parameters (pulse energy, repetition rate, and welding speed). Results showed that the formation of intermetallic brittle phases and welding defects could be effectively reduced. Strong welding quality with more than 210 MPa tensile strength for stainless steel-aluminum and 175 MPa tensile strength for stainless steel-magnesium has been demonstrated. A minimal heat affected zone and uniform and homogenous phase transformation in the welding region have been demonstrated. This laser-welding technique can be extended for various applications in semiconductor, automobile, aerospace, and biomedical industries. PMID:25322246

  14. CW single transverse mode all-fiber Tm3+-doped silica fiber laser

    NASA Astrophysics Data System (ADS)

    Song, E. Z.; Li, W. H.; You, L.

    2012-04-01

    The CW 25.6 W output power with a slope efficiency of 30.6% respected to the pump power from a CW single transverse mode all-fiber Tm3+-doped Silica Fiber Laser is reported. The all-fiber laser is made up by progressively splicing the pigtail fiber, matched FBG fiber and Tm fiber. The reflective FBG and Tm3+-doped fiber end Fresnel reflection build up the laser resonance cavity. Due to the multi-mode FBG as the reflective mirror, the output laser spectrum is multi-peaks at high output power, but the spectrum width is less than 2 nm at 1.94 μm. We estimate the beam quality to be M 2 = 2.39, clearly indicating nearly diffraction-limited beam propagation.

  15. 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.

  16. Recent developments in polycrystalline oxide fiber laser materials: production of Yb-doped polycrystalline YAG fiber

    NASA Astrophysics Data System (ADS)

    Lee, HeeDong; Keller, Kristin; Sirn, Brian; Parthasarathy, Triplicane; Cheng, Michael; Hopkins, Frank K.

    2011-09-01

    Laser quality, polycrystalline oxide fibers offer significant advantages over state-of-the-art silica fiber for high energy lasers. Advanced ceramic processing technology, along with a novel powder production process, has potential to produce oxide fibers with an outstanding optical quality for use in the fiber laser applications. The production of contaminant-free green fibers with a high packing density, as well as uniform packing distribution, is a key factor in obtaining laserquality fibers. High quality green fibers are dependent on the powder quality combined with the appropriate slurry formulation. These two fundamental technologies were successfully developed at UES, and used to produce Yb-doped yttrium aluminum garnet (YAG) fibers with high optical quality, high chemical purity, and suitable core diameters down to 20-30 microns.

  17. 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. PMID:24322095

  18. 2μm single frequency fiber laser based on thulium-doped silica fiber

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  20. 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. PMID:23938497

  1. Wide-Band Spatially Tunable Photonic Bandgap in Visible Spectral Range and Laser based on a Polymer Stabilized Blue Phase.

    PubMed

    Lin, Jia-De; Wang, Tsai-Yen; Mo, Ting-Shan; Huang, Shuan-Yu; Lee, Chia-Rong

    2016-01-01

    This work successfully develops a largely-gradient-pitched polymer-stabilized blue phase (PSBP) photonic bandgap (PBG) device with a wide-band spatial tunability in nearly entire visible region within a wide blue phase (BP) temperature range including room temperature. The device is fabricated based on the reverse diffusion of two injected BP-monomer mixtures with a low and a high chiral concentrations and afterwards through UV-curing. This gradient-pitched PSBP can show a rainbow-like reflection appearance in which the peak wavelength of the PBG can be spatially tuned from the blue to the red regions at room temperature. The total tuning spectral range for the cell is as broad as 165 nm and covers almost the entire visible region. Based on the gradient-pitched PSBP, a spatially tunable laser is also demonstrated in this work. The temperature sensitivity of the lasing wavelength for the laser is negatively linear and approximately -0.26 nm/°C. The two devices have a great potential for use in applications of photonic devices and displays because of their multiple advantages, such as wide-band tunability, wide operated temperature range, high stability and reliability, no issue of hysteresis, no need of external controlling sources, and not slow tuning speed (mechanically). PMID:27456475

  2. Wide-Band Spatially Tunable Photonic Bandgap in Visible Spectral Range and Laser based on a Polymer Stabilized Blue Phase

    PubMed Central

    Lin, Jia-De; Wang, Tsai-Yen; Mo, Ting-Shan; Huang, Shuan-Yu; Lee, Chia-Rong

    2016-01-01

    This work successfully develops a largely-gradient-pitched polymer-stabilized blue phase (PSBP) photonic bandgap (PBG) device with a wide-band spatial tunability in nearly entire visible region within a wide blue phase (BP) temperature range including room temperature. The device is fabricated based on the reverse diffusion of two injected BP-monomer mixtures with a low and a high chiral concentrations and afterwards through UV-curing. This gradient-pitched PSBP can show a rainbow-like reflection appearance in which the peak wavelength of the PBG can be spatially tuned from the blue to the red regions at room temperature. The total tuning spectral range for the cell is as broad as 165 nm and covers almost the entire visible region. Based on the gradient-pitched PSBP, a spatially tunable laser is also demonstrated in this work. The temperature sensitivity of the lasing wavelength for the laser is negatively linear and approximately −0.26 nm/°C. The two devices have a great potential for use in applications of photonic devices and displays because of their multiple advantages, such as wide-band tunability, wide operated temperature range, high stability and reliability, no issue of hysteresis, no need of external controlling sources, and not slow tuning speed (mechanically). PMID:27456475

  3. Wide-Band Spatially Tunable Photonic Bandgap in Visible Spectral Range and Laser based on a Polymer Stabilized Blue Phase

    NASA Astrophysics Data System (ADS)

    Lin, Jia-De; Wang, Tsai-Yen; Mo, Ting-Shan; Huang, Shuan-Yu; Lee, Chia-Rong

    2016-07-01

    This work successfully develops a largely-gradient-pitched polymer-stabilized blue phase (PSBP) photonic bandgap (PBG) device with a wide-band spatial tunability in nearly entire visible region within a wide blue phase (BP) temperature range including room temperature. The device is fabricated based on the reverse diffusion of two injected BP-monomer mixtures with a low and a high chiral concentrations and afterwards through UV-curing. This gradient-pitched PSBP can show a rainbow-like reflection appearance in which the peak wavelength of the PBG can be spatially tuned from the blue to the red regions at room temperature. The total tuning spectral range for the cell is as broad as 165 nm and covers almost the entire visible region. Based on the gradient-pitched PSBP, a spatially tunable laser is also demonstrated in this work. The temperature sensitivity of the lasing wavelength for the laser is negatively linear and approximately ‑0.26 nm/°C. The two devices have a great potential for use in applications of photonic devices and displays because of their multiple advantages, such as wide-band tunability, wide operated temperature range, high stability and reliability, no issue of hysteresis, no need of external controlling sources, and not slow tuning speed (mechanically).

  4. 150 W highly-efficient Raman fiber laser.

    PubMed

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

    2009-12-21

    We report a more than 150 W spectrally-clean continuous wave Raman fiber laser at 1120 nm with an optical efficiency of 85%. A approximately 30 m standard single mode silica fiber is used as Raman gain fiber to avoid second Stokes emission. A spectrally asymmetric resonator (in the sense of mirror reflection bandwidth) with usual fiber Bragg gratings is designed to minimize the laser power lost into the unwanted direction, even when the effective reflectivity of the rear fiber Bragg grating becomes as low as 81.5%. PMID:20052078

  5. A Compact 500 MHz Femtosecond All-Fiber Ring Laser

    NASA Astrophysics Data System (ADS)

    Yang, Tong; Huang, Huichang; Yuan, Xiaozhi; Wei, Xiaoming; He, Xin; Mo, Shupei; Deng, Huaqiu; Yang, Zhongmin

    2013-05-01

    We demonstrate a fundamentally mode-locked all-fiber ring laser with the repetition rate up to 500 MHz and pulse duration of 250 fs at 1.5 µm. Only an optical integrated module, a 4.8 cm Er3+/Yb3+-codoped phosphate glass fiber, and a polarization controller are employed to construct the all-fiber ring cavity. Stable mode-locking laser is output by adjusting the polarization controller.

  6. Nanosecond square pulse generation in fiber lasers with normal dispersion

    NASA Astrophysics Data System (ADS)

    Zhao, L. M.; Tang, D. Y.; Cheng, T. H.; Lu, C.

    2007-04-01

    We report on the generation of nanosecond square pulses in a passively mode-locked fiber ring laser made of purely normal dispersive fibers. Different to the noise-like pulse operation of the laser, the generated square pulses are stable and have no internal structures. We show that the formation of the square pulse is due to the combined action of the pulse peak clamping effect caused by the cavity and the almost linear pulse propagation in the normal dispersive fibers.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  8. 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. PMID:25606901

  9. 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. PMID:24978517

  10. Pulse-stretched Alexandrite laser for improved optical fiber reliability for laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Simons, David; Koschmann, Eric C.

    1992-06-01

    Clinical data shows that short pulse duration lasers used in laser induced shock wave lithotripsy severely damage optical fibers on both the proximal and distal ends which is unsuitable for clinical use. An Alexandrite laser system has been developed that uses dynamic pulse stretching of the Q-switched laser pulse and improved optical fiber coupling to eliminate the fiber damage. The method of pulse stretching presented controls the laser output pulse energy from 50 to 150 millijoules and temporal shape from 0.5 to 1.5 microseconds. This yields effective fragmentation of calculi without damage to the optical fiber.

  11. Characteristics research on self-amplified distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Song, Zhiqiang; Qi, Haifeng; Guo, Jian; Wang, Chang; Peng, Gangding

    2014-09-01

    A distributed feedback (DFB) fiber laser with a ratio of the backward to forward output power of 1:100 was composed by a 45-mm-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL-980-Hp erbium-doped fiber to absorb the surplus pump power after the active phase-shifted fiber grating and get population inversion. By using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with the narrow line-width and low noise, a narrow-band light filter consisting of a fiber Bragg grating (FBG) with the same Bragg wavelength as the laser and an optical circulator was used to filter the amplified spontaneous emission (ASE) noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, and a DFB fiber laser with the 32.5-mW output power, 11.5-kHz line width, and -87-dB/Hz relative intensity noise (RIN) at 300 mW of 980 nm pump power was brought out.

  12. 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.

  13. Laser Processing of Carbon Fiber Reinforced Polymer Composite for Optical Fiber Guidelines

    NASA Astrophysics Data System (ADS)

    Lima, M. S. F.; Sakamoto, J. M. S.; Simoes, J. G. A.; Riva, R.

    The replacement of copper wires by optical fibers for control and monitoring of aircraft systems are gaining more and more acceptance due to weight reductions and their intrinsic reliability. The present investigation proposes a new method for producing fiber optical guidelines in carbon fiber reinforced polymer (CFRP) composites using laser texturing and machining. Laser texturing was used to improve the adhesion bonding between the CFRP parts and laser machining is used to create a channel where the optical fiber will be placed and protected. The results show that using only 20 W of a Nd:YAG pulsed laser it is possible to enhance the joint resistance of CFRP composites and also protecting the optical fiber embedded in between two CFRP pieces. Using the proposed technology, the maximum load of a lap joint increased by 85% and the optical fiber remained integral even under severe bending conditions.

  14. 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.

  15. CO2 Laser Radiation Transmission Through Curved Hollow Fibers

    NASA Astrophysics Data System (ADS)

    Dror, Jacob; Gannot, Israel; Morhaim, Orna; Mendlovic, David; Croitoru, Nathan I.

    1989-07-01

    Hollow plastic fibers were produced by depositing metallic and dielectric films on the internal surface of plastic tubes. These fibers can transmit high CO2 laser energy with low atten-uation even in curved trajectories. A mathematical model was developed to describe the energy transmission. The energy distribution at the outlet of the fiber was measured and found to be influenced by the existence of whispering gallery mode. These fibers are suitable for surgical uses.

  16. 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.

  17. Simple design for singlemode high power CW fiber laser using multimode high NA fiber

    NASA Astrophysics Data System (ADS)

    Morasse, Bertrand; Chatigny, Stéphane; Desrosiers, Cynthia; Gagnon, Éric; Lapointe, Marc-André; de Sandro, Jean-Philippe

    2009-02-01

    A large number of high power CW fiber lasers described in the literature use large mode area (LMA) double cladding fibers. These fibers have large core and low core numerical aperture (NA) to limit the number of supported modes and are typically operated under coiling to eliminate higher order modes. We describe here multimode (MM) high NA ytterbium doped fibers used in single mode output high power laser/amplifier configuration. Efficient single mode amplification is realized in the multimode doped fiber by matching the fundamental mode of the doped fiber to the LP01 mode of the fiber Bragg grating (FBG) and by selecting the upper V-number value that limits the overlap of the LP01 to the higher order modes. We show that negligible mode coupling is realized in the doped fiber, which ensures a stable power output over external perturbation without the use of tapers. Fundamental mode operation is maintained at all time without coiling through the use of FBG written in a single mode fiber. We show that such fiber is inherently more photosensitive and easier to splice than LMA fiber. We demonstrate an efficient 75W singlemode CW fiber laser using this configuration and predict that the power scaling to the kW level can be achieved, the design being more practical and resistant to photodarkening compared to conventional low NA LMA fiber.

  18. Design and refinement of rare earth doped multicore fiber lasers

    NASA Astrophysics Data System (ADS)

    Prudenzano, F.; Mescia, L.; Di Tommaso, A.; Surico, M.; De Sario, M.

    2013-09-01

    A novel multicore ytterbium doped fiber laser is designed, with the target of maximizing both the effective mode area and the beam quality, by means of a complete home-made computer code. It can be employed to construct high power and Quasi-Gaussian beam lasers. The novel laser configuration exploits a single mode multicore fiber and does not need Talbot cavity or other in-phase mode selection mechanisms. This is an innovative solution, because to the best of our knowledge, for the first time, we have designed a truly single-mode multicore fiber laser. For comparison we have optimized two other laser configurations which are well known in literature, both employing a multimode multicore fiber and a Talbot cavity as a feedback for the in-phase supermode selection. All three multicore fibers, constituted by the same glass, are doped with the same ytterbium ion concentration and pumped with the same input power. Multimodal fiber lasers exhibit lower beam quality, i.e. a higher beam quality factor M2, with respect to the single mode one, even if suitable Talbot cavities are designed, but they are very competitive when a more compact laser cavity is required for the same output power. The novel single mode nineteen core laser exhibits a simulated effective mode area Aeff = 703 μm2 and a beam quality factor M2 = 1.05, showing better characteristics than the other two lasers.

  19. Endovenous laser ablation with TM-fiber laser

    NASA Astrophysics Data System (ADS)

    Somunyudan, Meral Filiz; Topaloglu, Nermin; Ergenoglu, Mehmet Umit; Gulsoy, Murat

    2011-03-01

    Endovenous Laser Ablation (EVLA) has become a popular minimally invasive alternative to stripping in the treatment of saphenous vein reflux. Several wavelengths have been proposed; of which 810, 940 and 980- nm are the most commonly used. However, the most appropriate wavelength is still the subject of debate. Thermal shrinkage of collagenous tissue during EVLA plays a significant role in the early and late results of the treatment. The aim of this study is to compare the efficacy of 980 and 1940-nm laser wavelengths in the treatment of varicose veins. In this study, 980 and 1940-nm lasers at different power settings (8/10W for 980-nm, 2/3W for 1940-nm) were used to irradiate stripped human veins. The most prominent contraction and narrowing in outer and inner diameter were observed with the 1940-nm at 2W, following 980-nm at 8W, 1940-nm at 3W and finally 980-nm at 10W. The minimum carbonization was observed with the 1940-nm at 2W. As a conclusion, 1940-nm Tm-fiber laser which has a significant effect in the management of varicose veins due to more selective energy absorption in water and consequently in the vein is a promising method in the management of varicose veins.

  20. Resonant tandem pumping of Tm-doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Creeden, Daniel; Johnson, Benjamin R.; Rines, Glen A.; Setzler, Scott D.

    2014-06-01

    We have demonstrated efficient lasing of a Tm-doped fiber when pumped with another Tm-doped fiber. In these experiments, we use a 1908 nm Tm-doped fiber laser as a pump source for another Tm-doped fiber laser, operating at a slightly longer wavelength (~2000 nm). Pumping in the 1900 nm region allows for very high optical efficiencies, low heat generation, and significant power scaling potential due to the use of fiber laser pumping. The trade-off is that the ground-state pump absorption at 1908 nm is ~37 times lower than at 795nm. However, the absorption cross-section is still sufficiently high enough to achieve effective pump absorption without exceedingly long fiber lengths. This may also be advantageous for distributing the thermal load in higher power applications.

  1. 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. PMID:22614601

  2. Hole drilling with fiber-optically delivered visible lasers

    SciTech Connect

    Kautz, D.D.; Berzins, L.V.; Dragon, E.P.

    1994-12-31

    The use of lasers for high-speed drilling of holes in materials is well documented. To allow easier use of lasers in manufacturing processes, fiber-optically delivered beams are preferable to the use of conventional optics. Lawrence Livermore National Laboratory (LLNL) has adapted fiber-optic technology to its visible light, copper vapor lasers for use in hole drilling studies. Visible lasers afford better coupling of light to the workpiece and when fiber-optically delivered, allow high quality holes to be drilled in difficult accessibility areas and with easier setup. A fiber-optic delivery system was attached to the presently hard-optic copper vapor laser system. This system consisted of a 0.6 mm (0.024 in.) fiber that was then telescoped and refocused by a hard optics package at the workstation end of the fiber. The optics package produced a 0.2 mm (0.008 in.) focused spot size at the workpiece. This system was then run down to a 3-axis CNC machining table to allow part movement for these studies. The fiber-optically delivered light was found to work extremely well for drilling small diameter holes. In summary, it was found that fiber-optically delivered, visible laser beams have several advantages in drilling over those same beams delivered through conventional hard optics. These include much easier setup, reduced system maintenance, and typically higher hole quality.

  3. Characteristics research of self-amplified distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Song, Zhiqiang; Qi, Haifeng; Guo, Jian; Wang, Chang; Peng, Gangding

    2013-09-01

    A distributed feedback (DFB) fiber laser with a ratio of backward to forward output power of 1:100 was composed by a 45mm length asymmetrical phase-shifted fiber grating fabricated on 50mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL980-Hp erbium-doped fiber to absorb surplus pump power after the active phase-shifted fiber grating and get population inversion. Using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with narrow line-width and low noise, a narrow-band light filter consisted of a FBG with the same Bragg wavelength as the laser and an optical circulator was used to filter the ASE noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, a DFB fiber laser of 32.5mW output power, 11.5 kHz line width, and -87dB/Hz relative intensity noise (RIN) at 300mW of 980 nm pump power was brought out.

  4. UV laser-surface interactions relevant to analytic spectroscopy of wide bandgap materials

    SciTech Connect

    Dickinson, J.T.

    1993-12-31

    Laer ablation has application in materials analysis, surface modification, and thin film deposition. Processes that lead to emission and formation of particles when wide band gap materials are irradiated with pulsed uv laser light. These materials are often difficult to transport into the gas phase for analysis. Such materials are alkali halides, MgO.

  5. Q-switched Tm-doped fiber lasers using dynamic microbends in oval-coating fibers

    NASA Astrophysics Data System (ADS)

    Araki, S.; Kimpara, K.; Tomiki, M.; Sakata, H.

    2013-06-01

    We present Q-switched pulse generation in a thulium-doped fiber laser by inducing a piezoelectric-driven microbend into an oval-coating fiber. The oval-coating fiber is made of a single-mode fiber in which an acrylic coating is flattened by thermal pressing. A pulse peak power of 1.45 W is obtained with a pump power of 139 mW.

  6. Biologically inspired band-edge laser action from semiconductor with dipole-forbidden band-gap transition

    PubMed Central

    Wang, Cih-Su; Liau, Chi-Shung; Sun, Tzu-Ming; Chen, Yu-Chia; Lin, Tai-Yuan; Chen, Yang-Fang

    2015-01-01

    A new approach is proposed to light up band-edge stimulated emission arising from a semiconductor with dipole-forbidden band-gap transition. To illustrate our working principle, here we demonstrate the feasibility on the composite of SnO2 nanowires (NWs) and chicken albumen. SnO2 NWs, which merely emit visible defect emission, are observed to generate a strong ultraviolet fluorescence centered at 387 nm assisted by chicken albumen at room temperature. In addition, a stunning laser action is further discovered in the albumen/SnO2 NWs composite system. The underlying mechanism is interpreted in terms of the fluorescence resonance energy transfer (FRET) from the chicken albumen protein to SnO2 NWs. More importantly, the giant oscillator strength of shallow defect states, which is served orders of magnitude larger than that of the free exciton, plays a decisive role. Our approach therefore shows that bio-materials exhibit a great potential in applications for novel light emitters, which may open up a new avenue for the development of bio-inspired optoelectronic devices. PMID:25758749

  7. Biologically inspired band-edge laser action from semiconductor with dipole-forbidden band-gap transition

    NASA Astrophysics Data System (ADS)

    Wang, Cih-Su; Liau, Chi-Shung; Sun, Tzu-Ming; Chen, Yu-Chia; Lin, Tai-Yuan; Chen, Yang-Fang

    2015-03-01

    A new approach is proposed to light up band-edge stimulated emission arising from a semiconductor with dipole-forbidden band-gap transition. To illustrate our working principle, here we demonstrate the feasibility on the composite of SnO2 nanowires (NWs) and chicken albumen. SnO2 NWs, which merely emit visible defect emission, are observed to generate a strong ultraviolet fluorescence centered at 387 nm assisted by chicken albumen at room temperature. In addition, a stunning laser action is further discovered in the albumen/SnO2 NWs composite system. The underlying mechanism is interpreted in terms of the fluorescence resonance energy transfer (FRET) from the chicken albumen protein to SnO2 NWs. More importantly, the giant oscillator strength of shallow defect states, which is served orders of magnitude larger than that of the free exciton, plays a decisive role. Our approach therefore shows that bio-materials exhibit a great potential in applications for novel light emitters, which may open up a new avenue for the development of bio-inspired optoelectronic devices.

  8. 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.

  9. Completely monolithic linearly polarized high-power fiber laser oscillator

    NASA Astrophysics Data System (ADS)

    Belke, Steffen; Becker, Frank; Neumann, Benjamin; Ruppik, Stefan; Hefter, Ulrich

    2014-03-01

    We have demonstrated a linearly polarized cw all-in-fiber oscillator providing 1 kW of output power and a polarization extinction ratio (PER) of up to 21.7 dB. The design of the laser oscillator is simple and consists of an Ytterbium-doped polarization maintaining large mode area (PLMA) fiber and suitable fiber Bragg gratings (FBG) in matching PLMA fibers. The oscillator has nearly diffraction-limited beam quality (M² < 1.2). Pump power is delivered via a high power 6+1:1 pump coupler. The slope efficiency of the laser is 75 %. The electro/optical efficiency of the complete laser system is ~30 % and hence in the range of Rofin's cw non-polarized fiber lasers. Choosing an adequate bending diameter for the Yb-doped PLMA fiber, one polarization mode as well as higher order modes are sufficiently supressed1. Resulting in a compact and robust linearly polarized high power single mode laser without external polarizing components. Linearly polarized lasers are well established for one dimensional cutting or welding applications. Using beam shaping optics radially polarized laser light can be generated to be independent from the angle of incident to the processing surface. Furthermore, high power linearly polarized laser light is fundamental for nonlinear frequency conversion of nonlinear materials.

  10. High power 938 nanometer fiber laser and amplifier

    DOEpatents

    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.

  11. 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.

  12. High-power single-frequency fiber lasers

    NASA Astrophysics Data System (ADS)

    Guan, Weihua

    Single frequency laser sources are desired in many applications. Various architectures for achieving high power single frequency fiber laser outputs have been investigated and demonstrated. Axial gain apodization can affect the lasing threshold and spectral modal discrimination of DFB lasers. Modeling results show that if properly tailored, the lasing threshold can be reduced by 21% without sacrificing modal discrimination, while simultaneously increasing the differential output power between both ends of the laser. A dual-frequency 2 cm silica fiber laser with a wavelength spacing of 0.3 nm was demonstrated using a polarization maintaining (PM) fiber Bragg grating (FBG) reflector. The output power reached 43 mW with the optical signal to noise ratio (OSNR) greater than 60 dB. By thermally tuning the overlap between the spectra of PM FBG and SM FBG, a single polarisation, single frequency fibre laser was also demonstrated with an output power of 35 mW. From the dual frequency fiber laser, dual frequency switching was achieved by tuning the pump power of the laser. The dual frequency switching was generated by the thermal effects of the absorbed pump in the ytterbium doped fiber. Suppression and elimination of self pulsing in a watt level, dual clad ytterbium doped fiber laser was demonstrated. Self pulsations are caused by the dynamic interaction between the photon population and the population inversion. The addition of a long section of passive fiber in the laser cavity makes the gain recovery faster than the self pulsation dynamics, allowing only stable continuous wave lasing. A single frequency, hybrid Brillouin/ytterbium fiber laser was demonstrated in a 12 m ring cavity The output power reached 40 mW with an OSNR greater than 50 dB. To scale up the output power, a dual clad hybrid Brillouin/ytterbium fiber laser was studied. A numerical model including third order SBS was used to calculate the laser power performance. Simulation shows that 5 W single

  13. Below band-gap laser ablation of diamond for transmission electron microscopy

    NASA Technical Reports Server (NTRS)

    George, T.; Foote, M. C.; Vasquez, R. P.; Fortier, E. P.; Posthill, J. B.

    1993-01-01

    A 248 nm excimer laser was used to thin naturally occurring type 1a diamond substrates at normal and glancing (22 deg) incidence. Perforation of a 250-micron-thick substrate was achieved in about 15 min at normal incidence. While the substrate thinned at glancing incidence was found to have large electron-transparent areas, that thinned at normal incidence required additional argon-ion milling to achieve electron transparency. X-ray photoelectron spectroscopy of the back surface of the diamond failed to detect any graphite or glassy carbon, confirming that damage due to laser ablation occurs only at the incident surface. Samples prepared using this technique imaged in the transmission electron microscope were observed to have retained the nitrogen platelets characteristic of such type 1a diamonds.

  14. Optical Fiber Multiplexer For Industrial Nd:YAG Lasers

    NASA Astrophysics Data System (ADS)

    Goethals, Walther A.

    1989-03-01

    A lot of industrial Nd:YAG lasers are now being equipped with fiber optics for application in flexible manufacturing. One laser can be supplied with several fibers so different processing positions can receive laser power according to the time-and/or energy sharing principle. Most of the time-sharing devices (multiplexers) are based on a galvanometer mirror that couples a converging laser beam into different fibers respectively. From the industry several questions have risen to make these multiplexers faster, more reliable and suitable for smaller diameter fibers. The current designs are limited by the positioning accuracy of the galvanometer mirror and by their sensitiveness to variations in the parameters of the laser beam due to thermal lensing effects. In the patented design of the multiplexer presented here, based on a telescopic image relay and a precision fiber positioning unit, these problems were solved. A prototype has been built which addresses five fibers with 200 μm cores at a switching rate higher than 100 times per second. The fibers have special termination connectors and can be exchanged easily without losing the alignment of the optical system. For spot welding applications with pulsed Nd:YAG lasers this means that this type of multiplexer could be used to take advantage of the high laser pulse rates and the pulse shape and energy programming possibilities that manufacturers of these types of lasers offer nowadays. Another application that has been shown now is the use of several remote laser engraving units served by a single CW/Q-Switched Nd:YAG laser and a fiber multiplexer.

  15. 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.

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

    NASA Astrophysics Data System (ADS)

    Thombansen, Ulrich; Gatej, Alexander; Pereira, Milton

    2015-01-01

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

  17. Two-mode multiplexing at 2 × 10.7 Gbps over a 7-cell hollow-core photonic bandgap fiber.

    PubMed

    Xu, Jing; Peucheret, Christophe; Lyngsø, Jens Kristian; Leick, Lasse

    2012-05-21

    Current technologies are fast approaching the capacity limit of single mode fibers (SMFs). Hollow-core photonic bandgap fibers (HC-PBGFs) are expected to provide attractive long-term solutions in terms of ultra-low fiber nonlinearities associated with the possibility of mode scaling, thus enabling mode division multiplexing (MDM). In this work, we demonstrate MDM over a HC-PBGF for the first time. Two 10.7 Gbps channels are simultaneously transmitted over two modes of a 30-m long 7-cell HC-PBGF. Bit error ratio (BER) performances below the FEC threshold limit (3.3 × 10(-3)) are shown for both data channels when the two modes are transmitted simultaneously. No power penalty and up to 3 dB power penalty at a BER of 10(-9) are measured for single mode transmission using the fundamental and the LP(11) mode, respectively. The performance of this exploratory demonstration is expected to improve significantly if advanced mode launching and detection methods are used. PMID:22714232

  18. Single frequency fiber laser at 2.05 μm based on Ho-doped germanate glass fiber

    NASA Astrophysics Data System (ADS)

    Wu, Jianfeng; Yao, Zhidong; Zong, Jie; Chavez-Pirson, Arturo; Peyghambarian, Nasser; Yu, Jirong

    2009-02-01

    A single frequency fiber laser operating near 2 micron with over 50 mW output power has been demonstrated by using a short piece of newly developed single mode holmium-doped germanate glass fiber. Laser from 2004 nm to 2083 nm was demonstrated from a short Ho-doped fiber laser cavity. A heavily thulium-doped germanate fiber was used as an in-band pump source for the holmium-doped fiber laser. The single frequency fiber laser can be thermally tuned.

  19. 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.

  20. Passive mode locking in erbium-ytterbium fiber lasers

    NASA Astrophysics Data System (ADS)

    Thai, Serey; Hayduk, Michael J.

    1999-11-01

    A novel mode-locked erbium-ytterbium fiber laser operating at 1550 nm using multiple quantum well (MQW) saturable absorbers was developed. The laser was constructed in a Fabry-Perot configuration using a fiber Bragg grating as a front reflector and a fiber Bragg grating output as a back reflector of the laser cavity. The passive mode-locking element placed inside the laser cavity is a 75 period InGaAs/InAlAs MQW saturable absorber grown lattice matched on an InP substrate. The output of the laser was taken through the other available port of a wavelength-division demultiplexer. The laser produced mode-locked output pulse trains at 16.67-MHz repetition rate and 10 mW of average output power.

  1. Volume Bragg grating stabilized spectrally narrow Tm fiber laser.

    PubMed

    McComb, Timothy; Sudesh, Vikas; Richardson, Martin

    2008-04-15

    A Tm-doped large mode area (LMA) silica fiber laser has been locked to a stable wavelength of 2,053.9 nm using a volume Bragg grating (VBG). The measured spectral width of the laser output was <300 pm, limited by the spectrometer resolution. Although this laser had modest output (approximately 5W) and slope efficiency (41%), this new approach to spectrally limiting the output of LMA fiber lasers is inherently extendable to kilowatt powers, opening up several applications including high-power pulsed fiber lasers and spectral beam combining. Performance characteristics of the laser compared to one using a dielectric mirror as a high reflector are described, and the results imply low VBG losses. PMID:18414564

  2. 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.

  3. High power, high efficiency diode pumped Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Glick, Yaakov; Fromzel, Viktor; Zhang, Jun; Dahan, Asaf; Ter-Gabrielyan, Nikolay; Pattnaik, Radha K.; Dubinskii, Mark

    2016-06-01

    We demonstrate a high power high efficiency Raman fiber laser pumped directly by a laser diode module at 976 nm. 80 Watts of CW power were obtained at a wavelength of 1020 nm with an optical-to-optical efficiency of 53%. When working quasi-CW, at a duty cycle of 30%, 85 W of peak power was produced with an efficiency of 60%. A commercial graded-index (GRIN) core fiber acts as the Raman fiber in a power oscillator configuration, which includes spectral selection to prevent generation of the 2nd Stokes. In addition, significant brightness enhancement of the pump beam is attained due to the Raman gain distribution profile in the GRIN fiber. To the best of our knowledge, this is the highest power Raman fiber laser directly pumped by laser diodes, which also exhibits a record efficiency for such a laser. In addition, it is the highest power Raman fiber laser (regardless of pumping source) demonstrated based on a GRIN fiber.

  4. Laser transmission welding of long glass fiber reinforced thermoplastics

    NASA Astrophysics Data System (ADS)

    van der Straeten, Kira; Engelmann, Christoph; Olowinsky, Alexander; Gillner, Arnold

    2015-03-01

    Joining fiber reinforced polymers is an important topic for lightweight construction. Since classical laser transmission welding techniques for polymers have been studied and established in industry for many years joint-strengths within the range of the base material can be achieved. Until now these processes are only used for unfilled and short glass fiber-reinforced thermoplastics using laser absorbing and laser transparent matrices. This knowledge is now transferred to joining long glass fiber reinforced PA6 with high fiber contents without any adhesive additives. As the polymer matrix and glass fibers increase the scattering of the laser beam inside the material, their optical properties, changing with material thickness and fiber content, influence the welding process and require high power lasers. In this article the influence of these material properties (fiber content, material thickness) and the welding parameters like joining speed, laser power and clamping pressure are researched and discussed in detail. The process is also investigated regarding its limitations. Additionally the gap bridging ability of the process is shown in relation to material properties and joining speed.

  5. Switchable quadruple-wavelength Erbium-doped fiber laser based on a chirped fiber grating and polarization-maintaining fiber

    NASA Astrophysics Data System (ADS)

    Cheng, Jianqun; Chen, Weicheng; Chen, Guojie

    2016-04-01

    A switchable quadruple-wavelength Erbium-doped fiber laser based on two Sagnac loops with a chirped fiber grating and polarization-maintaining fiber is proposed and demonstrated experimentally at room temperature. The two loops act as comb filters to excite multi-wavelength output. On the basis of the polarization hole burning effect, the laser can switch flexibly to output ten different modes from single-wavelength to quadruple-wavelength. All of the lasing lines with narrow linewidth have the optical signal-to-noise ratio of more than 35 dB. The laser with good power uniformity shows better stability with respect to the wavelength and peak power.

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

    PubMed Central

    Fu, Hongyan; Chen, Daru; Cai, Zhiping

    2012-01-01

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

  7. Fiber sensor systems based on fiber laser and microwave photonic technologies.

    PubMed

    Fu, Hongyan; Chen, Daru; Cai, Zhiping

    2012-01-01

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

  8. Optical Fiber Sensing Based on Reflection Laser Spectroscopy

    PubMed Central

    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. PMID:22294902

  9. Wavelength switchable graphene Q-switched fiber laser with cascaded fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Wu, Man; Chen, Shuqing; Chen, Yu; Li, Ying

    2016-06-01

    We have demonstrated a wavelength switchable graphene Q-switched fiber laser with two cascaded fiber Bragg gratings. Stable Q-switching operation with central wavelength 1542.9 nm (1543.7 nm), repetition rate 28.4 kHz (22.58 kHz), and pulse duration 2.16 μs (2.65 μs) can be obtained by adjusting the intra-cavity birefringence. Moreover, stable dual-wavelength operation with wavelength spacing 0.8 nm can also be observed. The cascaded fiber gratings combined with the graphene saturable absorber provide a simple and feasible way to get versatile pulsed fiber laser.

  10. Efficient single-frequency fiber lasers with novel photosensitive Er/Yb optical fibers.

    PubMed

    Dong, L; Loh, W H; Caplen, J E; Minelly, J D; Hsu, K; Reekie, L

    1997-05-15

    Boron- and germanium-doped highly photosensitive cladding is used in a novel design to achieve photosensitive Er/Yb-doped fibers, permitting short, strong gratings (length approximately 1 cm, reflectivity >99%) to be written without hydrogenation. The high absorption at 980 nm in Er/Yb fibers permits efficient pump absorption over a short device length, which is ideal for achieving highly efficient single-frequency fiber lasers. Both single-frequency Bragg-grating reflector and distributed-feedback lasers with slope efficiencies of 25% with respect to launched pump power have been realized in such fibers. PMID:18185631

  11. Blue laser via IR resonant doubling with 71% fiber to fiber efficiency

    NASA Astrophysics Data System (ADS)

    Danekar, Koustubh; Khademian, Ali; Shiner, David

    2011-08-01

    We report on high efficiency resonant doubling to 486nm using periodically poled KTP. The IR laser source is an FBG stabilized semiconductor laser with a maximum polarization maintaining (PM) fiber coupled output of 840mW. An output power of 680mW at 486nm was obtained from our optimized cavity, giving net efficiency of 81%. Also, we report an 87.5% net efficiency in coupling of this blue light from the servo locked cavity into a single-mode PM fiber. This gives a total of 71% fiber to fiber efficiency. Furthermore, a wall plug efficiency of 21.4% was obtained.

  12. Blue laser via IR resonant doubling with 71% fiber to fiber efficiency.

    PubMed

    Danekar, Koustubh; Khademian, Ali; Shiner, David

    2011-08-01

    We report on high efficiency resonant doubling to 486 nm using periodically poled KTP. The IR laser source is an FBG stabilized semiconductor laser with a maximum polarization maintaining (PM) fiber coupled output of 840 mW. An output power of 680 mW at 486 nm was obtained from our optimized cavity, giving net efficiency of 81%. Also, we report an 87.5% net efficiency in coupling of this blue light from the servo locked cavity into a single-mode PM fiber. This gives a total of 71% fiber to fiber efficiency. Furthermore, a wall plug efficiency of 21.4% was obtained. PMID:21808365

  13. 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

  14. Hole drilling on glass optical fibers by a femtosecond laser

    NASA Astrophysics Data System (ADS)

    Hamasaki, Masayuki; Gouya, Kenji; Watanabe, Kazuhiro

    2012-01-01

    A novel optical fiber sensor has been developed for gaseous material detection by means of a femto-second laser which has ultrashort pulse and ultrahigh peak power. This sensor has attractive sensor potion consisted of drilling holes array which is machined on the glass optical fiber. Additionally, the sensor potion is coated with thin gold film. This work expects that an interaction could be induced between transmitted light through fiber core and a bottom of the drilled holes which reaches the fiber core. The interaction could induce near-field optical phenomenon excited by transmitted light through the fiber core. This scheme could make it possible to detect gaseous-material phase substances around the optical fiber. In this study, we found that localized surface plasmon (LSP) was excited by the transmitted light through the fiber core. This paper shows experiment to obtain optimum irradiation conditions and investigation for sensor principle for the development of a novel fiber sensor.

  15. 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.

  16. 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. PMID:26030549

  17. Application of fiber laser for a Higgs factory

    SciTech Connect

    Chou, W.

    2014-06-04

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

  18. SURFACE MORPHOLOGY OF CARBON FIBER POLYMER COMPOSITES AFTER LASER STRUCTURING

    SciTech Connect

    Sabau, Adrian S; Chen, Jian; Jones, Jonaaron F.; Alexandra, Hackett; Jellison Jr, Gerald Earle; Daniel, Claus; Warren, Charles David; Rehkopf, Jackie D.

    2015-01-01

    The increasing use of Carbon Fiber Polymer Composite (CFPC) as a lightweight material in automotive and aerospace industries requires the control of surface morphology. In this study, the composites surface was prepared by ablating the resin in the top fiber layer of the composite using an Nd:YAG laser. The CFPC specimens with T700S carbon fiber and Prepreg - T83 resin (epoxy) were supplied by Plasan Carbon Composites, Inc. as 4 ply thick, 0/90o plaques. The effect of laser fluence, scanning speed, and wavelength was investigated to remove resin without an excessive damage of the fibers. In addition, resin ablation due to the power variation created by a laser interference technique is presented. Optical property measurements, optical micrographs, 3D imaging, and high-resolution optical profiler images were used to study the effect of the laser processing on the surface morphology.

  19. High performance FBG interrogation technology with scan fiber laser

    NASA Astrophysics Data System (ADS)

    Yang, Yuanhong; Ma, Youchun; Yang, Minwei

    2010-11-01

    A Fiber Bragg gratings (FBG) Interrogation scheme with scan fiber laser was demonstrated. The ring cavity scan fiber laser was investigated and the scan fiber laser module was made and test, the 200Hz scan frequency, ~0.02nm line width, more than 40nm scan range and more than 1 mW output power were obtained. A 12 channels, 20 FBGs per channel FBG interrogator was made with this laser module and the high speed signal process circuit base on FPGA. The centroid finding method which has advantage on interrogation speed and accurate was taken for finding the peak of the return FBG spectrum. The FBG interrogator was test and less than 3pm standard deviation with 200Hz scan frequency were obtained.

  20. Theoretical and Experimental Investigations of Novel Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Walton, Donnell Thaddeus

    Ultrafast science has historically been concerned with the areas of spectroscopy and the study of dynamic processes in the sciences and engineering. With the recent advent of compact, economical sources of ultrashort optical pulses, many potential applications have emerged in the fields of communications, medicine, metrology, and industrial processing. In this thesis, fiber lasers are explored as compact sources of ultra short optical pulses. Several passive modelocking schemes in fiber lasers have been reported. Unfortunately, when implemented in the negative group velocity regime, modelocked fiber lasers are plagued with a multiple-pulsing instability which limits them to low output pulse energy. In this work, a modelocking scheme based on a nonlinear directional coupler is proposed and analyzed. This laser, when embodied as a dual-core fiber, is shown to be immune to the multiple-pulsing instability and produces sub-100-fs pulses in the negative group velocity regime. In the presence of gain saturation, the laser produces 100-fs pulses and can evolve to steady-state from initial noise input when operated under the right conditions. The dual-core fiber laser even produces nanojoule, picosecond when implemented in the regime of positive group velocity dispersion. These pulses are chirped which allows for further compression down to 160 fs. Using a similar model, the first theoretical analysis of passive modelocking in birefringent fiber is performed. The results of the model (45 fs) are in excellent agreement with experimental results (38 fs). Additional wavelengths are also needed if fiber lasers are to be considered viable as compact sources of ultrashort pulses. To this end, a diode-pumped thulium -doped fluorozirconate fiber laser which operates near 800 nm is examined. The upconversion process is shown to be due to avalanche absorption of the pump. By constructing a compact, diode-pumped laser from an unoptimized sample of this fiber, this technique is shown

  1. Photonic bandgap amorphous chalcogenide thin films with multilayered structure grown by pulsed laser deposition method

    NASA Astrophysics Data System (ADS)

    Zhang, Shao-qian; Němec, Petre; Nazabal, Virginie; Jin, Yu-qi

    2016-05-01

    Amorphous chalcogenide thin films were fabricated by the pulsed laser deposition technique. Thereafter, the stacks of multilayered thin films for reflectors and microcavity were designed for telecommunication wavelength. The prepared multilayered thin films for reflectors show good compatibility. The microcavity structure consists of Ge25Ga5Sb10S65 (doped with Er3+) spacer layer surrounded by two 5-layer As40Se60/Ge25Sb5S70 reflectors. Scanning/transmission electron microscopy results show good periodicity, great adherence and smooth interfaces between the alternating dielectric layers, which confirms a suitable compatibility between different materials. The results demonstrate that the chalcogenides can be used for preparing vertical Bragg reflectors and microcavity with high quality.

  2. Self-Frequency-Doubling Glass-Fiber Laser

    NASA Technical Reports Server (NTRS)

    Selker, Mark D.; Dallas, Joseph L.

    1993-01-01

    Specially prepared germanium and phosphorous-doped glass optical fiber doped with neodymium shown to act as self-frequency-doubling laser. Self-frequency-doubling fiber laser with further refinements, eliminates need for expensive, easily damaged, nonlinear crystals currently used. Enables one to avoid loss and damage mechanisms associated with interfaces of nonlinear crystals as well as to eliminate angle/temperature phase-matching tuning.

  3. Even Illumination from Fiber-Optic-Coupled Laser Diodes

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.

    2006-01-01

    A method of equipping fiber-optic-coupled laser diodes to evenly illuminate specified fields of view has been proposed. The essence of the method is to shape the tips of the optical fibers into suitably designed diffractive optical elements. One of the main benefits afforded by the method would be more nearly complete utilization of the available light. Diffractive optics is a relatively new field of optics in which laser beams are shaped by use of diffraction instead of refraction.

  4. Laser-Pulse/Fiber-Optic Liquid-Leak Detector

    NASA Technical Reports Server (NTRS)

    Padgett, M. E.

    1986-01-01

    Several potential leak sites monitored using single sensing fiber. Fluid systems monitored quickly for leaks in remote, hazardous, or inaccessible locations by system of compact, lightweight fiber-optic leak sensors presently undergoing development. Sensors installed at potential leak sites as joints, couplings, and fittings. Sensor read by sending laser pulse along fiber, then noting presence or relative amplitude of return pulse. Leak-monitoring technique applicable to wide range of fluid systems and minimizes human exposure to toxic or dangerous fluids.

  5. Phase generated carrier technique for fiber laser hydrophone

    NASA Astrophysics Data System (ADS)

    Li, Rizhong; Wang, Xinbing; Huang, Junbin; Gu, Hongcan

    2013-08-01

    A distributed feedback (DFB) fiber laser is compact, and is very suitable for using as a hydrophone to sense acoustic pressure. A DFB fiber laser hydrophone was researched. In the fiber laser hydrophone signal demodulating system, an unbalanced Michelson fiber interferometer and a Phase Generated Carrier (PGC) method were used. The PGC method can be used to demodulating the acoustic signal from the interference signal. Comparing with the Naval Research Laboratory (NRL) method and Naval Postgraduate School (NPS) method, the digitized PGC method requires a greater amount of computation because of the high signal sampling, but it demands only one interference signal which makes the less fiber connections of the fiber laser hydrophone array. So the fiber laser hydrophone array based on the PGC method has lower complexity and higher reliability than that based on the NRL method or NPS method. The experimental results approve that the PGC method can demodulate acoustic signal between 20~2000 Hz frequency range with good signal-to-noise ratio (SNR) when the PZT driving frequency is 20 kHz.

  6. Fiber-optic interferometer using frequency-modulated laser diodes

    NASA Technical Reports Server (NTRS)

    Beheim, G.

    1986-01-01

    This paper describes an electrically passive fiber-optic interferometer which uses dual frequency-modulated laser diodes. Experimental results show that this type of interferometer can attain a displacement range of 100 micron with subnanometer resolution. This technique can serve as the basis for a number of high-precision fiber-optic sensors.

  7. Visible continuum generation using a femtosecond erbium-doped fiber laser and a silica nonlinear fiber.

    PubMed

    Nicholson, J W; Bise, R; Alonzo, J; Stockert, T; Trevor, D J; Dimarcello, F; Monberg, E; Fini, J M; Westbrook, P S; Feder, K; Grüner-Nielsen, L

    2008-01-01

    Supercontinuum extending to visible wavelengths is generated in a hybrid silica nonlinear fiber pumped at 1560 nm by a femtosecond, erbium-doped fiber laser. The hybrid nonlinear fiber consists of a short length of highly nonlinear, germano-silicate fiber (HNLF) spliced to a length of photonic crystal fiber (PCF). A 2 cm length of HNLF provides an initial stage of continuum generation due to higher-order soliton compression and dispersive wave generation before launching into the PCF. The visible radiation is generated in the fundamental mode of the PCF. PMID:18157247

  8. High-brightness, fiber-coupled pump modules in fiber laser applications

    NASA Astrophysics Data System (ADS)

    Hemenway, Marty; Urbanek, Wolfram; Hoener, Kylan; Kennedy, Keith W.; Bao, Ling; Dawson, David; Cragerud, Emily S.; Balsley, David; Burkholder, Gary; Reynolds, Mitch; Price, Kirk; Haden, Jim; Kanskar, Manoj; Kliner, Dahv A.

    2014-03-01

    High-power, high-brightness, fiber-coupled pump modules enable high-performance industrial fiber lasers with simple system architectures, multi-kW output powers, excellent beam quality, unsurpassed reliability, and low initial and operating costs. We report commercially available (element™), single-emitter-based, 9xx nm pump sources with powers up to 130 W in a 105 μm fiber and 250 W in a 200 μm fiber. This combination of high power and high brightness translates into improved fiber laser performance, e.g., simultaneously achieving high nonlinear thresholds and excellent beam quality at kW power levels. Wavelength-stabilized, 976 nm versions of these pumps are available for applications requiring minimization of the gain-fiber length (e.g., generation of high-peak-power pulses). Recent prototypes have achieved output powers up to 300 W in a 200 μm fiber. Extensive environmental and life testing at both the chip and module level under accelerated and real-world operating conditions have demonstrated extremely high reliability, with innovative designs having eliminated package-induced-failure mechanisms. Finally, we report integrated Pump Modules that provide < 1.6 kW of fiber-coupled power conveniently formatted for fiber-laser pumping or direct-diode applications; these 19" rack-mountable, 2U units combine the outputs of up to 14 elements™ using fused-fiber combiners, and they include high-efficiency diode drivers and safety sensors.

  9. Application and the key technology on high power fiber-optic laser in laser weapon

    NASA Astrophysics Data System (ADS)

    Qu, Zhou; Li, Qiushi; Meng, Haihong; Sui, Xin; Zhang, Hongtao; Zhai, Xuhua

    2014-12-01

    The soft-killing laser weapon plays an important role in photoelectric defense technology. It can be used for photoelectric detection, search, blinding of photoelectric sensor and other devices on fire control and guidance devices, therefore it draws more and more attentions by many scholars. High power fiber-optic laser has many virtues such as small volume, simple structure, nimble handling, high efficiency, qualified light beam, easy thermal management, leading to blinding. Consequently, it may be used as the key device of soft-killing laser weapon. The present study introduced the development of high power fiber-optic laser and its main features. Meanwhile the key technology of large mode area (LMA) optical fiber design, the beam combination technology, double-clad fiber technology and pumping optical coupling technology was stated. The present study is aimed to design high doping LMA fiber, ensure single mode output by increasing core diameter and decrease NA. By means of reducing the spontaneous emission particle absorbed by fiber core and Increasing the power density in the optical fiber, the threshold power of nonlinear effect can increase, and the power of single fiber will be improved. Meantime, high power will be obtained by the beam combination technology. Application prospect of high power fiber laser in photoelectric defense technology was also set forth. Lastly, the present study explored the advantages of high power fiber laser in photoelectric defense technology.

  10. A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Bi, Wei-hong; Fu, Xing-hu; Jiang, Peng; Wu, Yang

    2015-11-01

    In this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss are equal, so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature. The experimental results show that the laser can output stable multi-wavelength lasers simultaneously. The laser coupling loss is small, the structure is simple, and it is convenient for integration, so it can be widely used in dense wavelength division multiplexing (DWDM) system and optical fiber sensors.

  11. Demodulation of a fiber Bragg grating strain sensor by a multiwavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Cong, Shan; Sun, Yunxu; Zhao, Yuxi; Pan, Lifeng

    2012-04-01

    A fiber Bragg grating (FBG) sensors system utilizing a multi-wavelength erbium-doped fiber lasers (EDFL) with frequency shifter is proposed. The system is one fiber laser cavity with two FBG sensors as its filters. One is for strain sensing, and the other one is for temperature compensation. A frequency shifter is used to suppress the mode competition to lase two wavelengths that correspond with FBGs. The wavelength shift of the EDFL represents the sensing quantity, which is demodulated by Fiber Fabry-Perot (FFP) filter. The sensor's response to strain is measured by experiment. Because of exploiting the dual-wavelength fiber laser with a frequency shifter forming the feedback as the light source, many advantages of this system are achieved, especially high signal-to-noise ratio, high detected power, and low power consuming comparing with conventional FBG sensor system utilizing broadband light as the light source. What's more, this structure is also easy to combine with FBG array.

  12. Demodulation of a fiber Bragg grating strain sensor by a multiwavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Cong, Shan; Sun, Yunxu; Zhao, Yuxi; Pan, Lifeng

    2011-11-01

    A fiber Bragg grating (FBG) sensors system utilizing a multi-wavelength erbium-doped fiber lasers (EDFL) with frequency shifter is proposed. The system is one fiber laser cavity with two FBG sensors as its filters. One is for strain sensing, and the other one is for temperature compensation. A frequency shifter is used to suppress the mode competition to lase two wavelengths that correspond with FBGs. The wavelength shift of the EDFL represents the sensing quantity, which is demodulated by Fiber Fabry-Perot (FFP) filter. The sensor's response to strain is measured by experiment. Because of exploiting the dual-wavelength fiber laser with a frequency shifter forming the feedback as the light source, many advantages of this system are achieved, especially high signal-to-noise ratio, high detected power, and low power consuming comparing with conventional FBG sensor system utilizing broadband light as the light source. What's more, this structure is also easy to combine with FBG array.

  13. Selective mode excitation in hollow-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Galea, A. D.; Couny, F.; Coupland, S.; Roberts, P. J.; Sabert, H.; Knight, J. C.; Birks, T. A.; Russell, Philip St. J.

    2005-04-01

    Modes are selectively excited by launching light through the cladding from the side into a hollow-core photonic crystal fiber. Measuring the total output power at the end of the fiber as a function of the angle of incidence of the exciting laser beam provides a powerful diagnostic for characterizing the cladding bandgap. Furthermore, various types of modes on either side of the bandgap are excited individually, and their near-field images are obtained.

  14. Preface to the Special Issue on short pulse fiber lasers

    NASA Astrophysics Data System (ADS)

    Delavaux, Jean-Marc P.; Grelu, Philippe; Pu, Wang; Ilday, Fatih Ömer

    2014-12-01

    In the last two decades the fiber laser has evolved from a laboratory curiosity to a viable tool in an increasing number of applications in such diverse areas as material processing, atmospheric monitoring, high energy physics, medicine, telecommunications, and defense. The reasons for the growing acceptance of fiber lasers lie in the combination of their many attractive features. Indeed, fiber lasers are together power efficient, compact, light weight, versatile and reliable. Initially, the development of fiber laser technology was led to challenge the dominance of well entrenched solid state lasers used in the lucrative manufacturing industry. Traditionally, the emission wavelength band of interest was mostly limited to the near infrared (NIR) region (i.e. from 1 to 1.6 μm). More recently, extensive fiber laser R&D advances have extended the laser applications to a broader spectrum, from the ultra violet (UV) to the mid-infrared (Mid-IR) wavelength region, and investigated the specific advantages associated with different pulse widths, from ns to fs, and different operating regimes.

  15. Ceramic bracket debonding with Tm:fiber laser

    NASA Astrophysics Data System (ADS)

    Demirkan, İrem; Sarp, Ayşe Sena Kabaş; Gülsoy, Murat

    2016-06-01

    Lasers have the potential for reducing the required debonding force and can prevent the mechanical damage given to the enamel surface as a result of conventional debonding procedure. However, excessive thermal effects limit the use of lasers for debonding purposes. The aim of this study was to investigate the optimal parameters of 1940-nm Tm:fiber laser for debonding ceramic brackets. Pulling force and intrapulpal temperature measurements were done during laser irradiation simultaneously. A laser beam was delivered in two different modes: scanning the fiber tip on the bracket surface with a Z shape movement or direct application of the fiber tip at one point in the center of the bracket. Results showed that debonding force could be decreased significantly compared to the control samples, in which brackets were debonded by only mechanical force. Intrapulpal temperature was kept equal or under the 5.5°C threshold value of probable thermal damage to pulp. Scanning was found to have no extra contribution to the process. It was concluded that using 1940-nm Tm:fiber laser would facilitate the debonding of ceramic brackets and can be proposed as a promising debonding tool with all the advantageous aspects of fiber lasers.

  16. Infrared glass fiber cables for CO laser medical applications

    NASA Astrophysics Data System (ADS)

    Arai, Tsunenori; Mizuno, Kyoichi; Sensaki, Koji; Kikuchi, Makoto; Watanabe, Tamishige; Utsumi, Atsushi; Takeuchi, Kiyoshi; Akai, Yoshiro

    1993-05-01

    We developed the medical fiber cables which were designed for CO laser therapy, i.e., angioplasty and endoscopic therapy. As-S chalcogenide glass fibers were used for CO laser delivery. A 230 micrometers core-diameter fiber was used for the angioplasty laser cable. The outer diameter of this cable was 600 micrometers . The total length and insertion length of the angioplasty laser cable were 2.5 m and 1.0 m, respectively. Typically, 2.0 W of fiber output was used in the animal experiment in vivo for the ablation of the model plaque which consisted of human atheromatous aorta wall. The transmission of the angioplasty laser cable was approximately 35%, because the reflection loss occurred at both ends of the fiber and window. Meanwhile, the core diameter of the energy delivery fiber for the endoscopic therapy was 450 micrometers . The outer diameter of this cable was 1.7 mm. Approximately 4.5 W of fiber output was used for clinical treatment of pneumothorax through a pneumoscope. Both types of the cables had the ultra-thin thermocouples for temperature monitoring at the tip of the cables. This temperature monitoring was extremely useful to prevent the thermal destruction of the fiber tip. Moreover, the As-S glass fibers were completely sealed by the CaF2 windows and outer tubes. Therefore, these cables were considered to have sufficient safety properties for medical applications. These laser cables were successfully used for the in vivo animal experiments and/or actual clinical therapies.

  17. Detachable fiber optic tips for use in thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas C.; Blackmon, Richard L.; Irby, Pierce B.; Fried, Nathaniel M.

    2013-03-01

    The thulium fiber laser (TFL) has recently been proposed as an alternative to the Holmium:YAG (Ho:YAG) laser for lithotripsy. The TFL's Gaussian spatial beam profile provides higher power transmission through smaller optical fibers with reduced proximal fiber tip damage, and improved saline irrigation and flexibility through the ureteroscope. However, distal fiber tip damage may still occur during stone fragmentation, resulting in disposal of the entire fiber after the procedure. A novel design for a short, detachable, distal fiber tip that can fit into an ureteroscope's working channel is proposed. A prototype, twist-lock, spring-loaded mechanism was constructed using micromachining methods, mating a 150-μm-core trunk fiber to 300-μm-core fiber tip. Optical transmission measuring 80% was observed using a 30-mJ pulse energy and 500-μs pulse duration. Ex vivo human calcium oxalate monohydrate urinary stones were vaporized at an average rate of 187 μg/s using 20-Hz modulated, 50% duty cycle 5 pulse packets. The highest stone ablation rates corresponded to the highest fiber tip degradation, thus providing motivation for use of detachable and disposable distal fiber tips during lithotripsy. The 1-mm outer-diameter prototype also functioned comparable to previously tested tapered fiber tips.

  18. Design of fiber optic probes for laser light scattering

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans S.; Chu, Benjamin

    1989-01-01

    A quantitative analysis is presented of the role of optical fibers in laser light scattering. Design of a general fiber optic/microlens probe by means of ray tracing is described. Several different geometries employing an optical fiber of the type used in lightwave communications and a graded index microlens are considered. Experimental results using a nonimaging fiber optic detector probe show that due to geometrical limitations of single mode fibers, a probe using a multimode optical fiber has better performance, for both static and dynamic measurements of the scattered light intensity, compared with a probe using a single mode fiber. Fiber optic detector probes are shown to be more efficient at data collection when compared with conventional approaches to measurements of the scattered laser light. Integration of fiber optic detector probes into a fiber optic spectrometer offers considerable miniaturization of conventional light scattering spectrometers, which can be made arbitrarily small. In addition static and dynamic measurements of scattered light can be made within the scattering cell and consequently very close to the scattering center.

  19. Optical Frequency Comb Generation based on Erbium Fiber Lasers

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  20. Fiber laser modelocked by nonlinear polarization rotation in a fiber loop

    NASA Astrophysics Data System (ADS)

    Kuzin, Evgueni A.; Ibarra-Escamilla, Baldeamr; Gomez-Garcia, D. E.; Haus, Joseph W.

    2002-07-01

    We present the experimental demonstration of a new fiber laser configuration based on the nonlinear optical loop mirror with a symmetrical coupler, and highly twisted low- birefringent fiber in the loop. The nonlinear optical loop mirror configuration operates by nonlinear polarization rotation.

  1. 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.

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

    PubMed

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

    2015-11-15

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

  3. Cascaded combiners for a high power CW fiber laser

    NASA Astrophysics Data System (ADS)

    Tan, Qirui; Ge, Tingwu; Zhang, Xuexia; Wang, Zhiyong

    2016-02-01

    We report cascaded combiners for a high power continuous wave (CW) fiber laser in this paper. The cascaded combiners are fabricated with an improved lateral splicing process. During the fusing process, there is no stress or tension between the pump fiber and the double-cladding fiber. Thus, the parameters of the combiner are better than those that have been reported. The coupling efficiency is 98.5%, and the signal insertion loss is 1%. The coupling efficiency of the cascaded combiners is 97.5%. The pump lights are individually coupled into the double-cladding fiber via five combiners. The thermal effects cannot cause damage to the combiners and the cascaded combiners can operate stably in high power CW fiber lasers. We also develop a high power CW fiber laser that generates a maximum 780 W of CW signal power at 1080 nm with 71% optical-to-optical conversion efficiency. The fiber laser is pumped via five intra-cavity cascaded combiners and five extra-cavity cascaded combiners with a maximum pump power of 1096 W and a pump wavelength of 975 nm.

  4. 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.

  5. Mode Selection for a Single-Frequency Fiber Laser

    NASA Technical Reports Server (NTRS)

    Liu, Jian

    2010-01-01

    A superstructured fiber-grating-based mode selection filter for a single-frequency fiber laser eliminates all free-space components, and makes the laser truly all-fiber. A ring cavity provides for stable operations in both frequency and power. There is no alignment or realignment required. After the fibers and components are spliced together and packaged, there is no need for specially trained technicians for operation or maintenance. It can be integrated with other modules, such as telescope systems, without extra optical alignment due to the flexibility of the optical fiber. The filter features a narrow line width of 1 kHz and side mode suppression ratio of 65 dB. It provides a high-quality laser for lidar in terms of coherence length and signal-to-noise ratio, which is 20 dB higher than solid-state or microchip lasers. This concept is useful in material processing, medical equipment, biomedical instrumentation, and optical communications. The pulse-shaping fiber laser can be directly used in space, airborne, and satellite applications including lidar, remote sensing, illuminators, and phase-array antenna systems.

  6. New fiber laser for lidar developments in disaster management

    NASA Astrophysics Data System (ADS)

    Besson, C.; Augere, B.; Canat, G.; Cezard, N.; Dolfi-Bouteyre, A.; Fleury, D.; Goular, D.; Lombard, L.; Planchat, C.; Renard, W.; Valla, M.

    2014-10-01

    Recent progress in fiber technology has enabled new laser designs along with all fiber lidar architectures. Their asset is to avoid free-space optics, sparing lengthy alignment procedures and yielding compact setups that are well adapted for field operations and on board applications thanks to their intrinsic vibration-resistant architectures. We present results in remote sensing for disaster management recently achieved with fiber laser systems. Field trials of a 3-paths lidar vibrometer for the remote study of modal parameters of buildings has shown that application-related constraints were fulfilled and that the obtained results are consistent with simultaneous in situ seismic sensors measurements. Remote multi-gas detection can be obtained using broadband infrared spectroscopy. Results obtained on methane concentration measurement using an infrared supercontinuum fiber laser and analysis in the 3-4 μm band are reported. For gas flux retrieval, air velocity measurement is also required. Long range scanning all-fiber wind lidars are now available thanks to innovative laser architectures. High peak power highly coherent pulses can be extracted from Er3+:Yb3+ and Tm3+ active fibers using methods described in the paper. The additional laser power provides increased coherent lidar capability in range and scanning of large areas but also better system resistance to adverse weather conditions. Wind sensing at ranges beyond 10 km have been achieved and on-going tests of a scanning system dedicated to airport safety is reported.

  7. Fiber Laser Front Ends for High-Energy Short Pulse Lasers

    SciTech Connect

    Dawson, J W; Liao, Z M; Mitchell, S; Messerly, M; Beach, R; Jovanovic, I; Brown, C; Payne, S A; Barty, C J

    2005-01-18

    We are developing an all fiber laser system optimized for providing input pulses for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal solutions for these systems as they are highly reliable and once constructed they can be operated with ease. Furthermore, they offer an additional benefit of significantly reduced footprint. In most labs containing equivalent bulk laser systems, the system occupies two 4'x8' tables and would consist of 10's if not a 100 of optics which would need to be individually aligned and maintained. The design requirements for this application are very different those commonly seen in fiber lasers. High energy lasers often have low repetition rates (as low as one pulse every few hours) and thus high average power and efficiency are of little practical value. What is of high value is pulse energy, high signal to noise ratio (expressed as pre-pulse contrast), good beam quality, consistent output parameters and timing. Our system focuses on maximizing these parameters sometimes at the expense of efficient operation or average power. Our prototype system consists of a mode-locked fiber laser, a compressed pulse fiber amplifier, a ''pulse cleaner'', a chirped fiber Bragg grating, pulse selectors, a transport fiber system and a large flattened mode fiber amplifier. In our talk we will review the system in detail and present theoretical and experimental studies of critical components. We will also present experimental results from the integrated system.

  8. Linearly polarized random fiber laser with ultimate efficiency.

    PubMed

    Zlobina, E A; Kablukov, S I; Babin, S A

    2015-09-01

    Linearly polarized pumping of a random fiber laser made of a 500-m PM fiber with PM fiber-loop mirror at one fiber end results in generation of linearly polarized radiation at 1.11 μm with the polarization extinction ratio as high as 25 dB at the output power of up to 9.4 W. The absolute optical efficiency of pump-to-Stokes wave conversion reaches 87%, which is close to the quantum limit and sets a record for Raman fiber lasers with random distributed feedback and with a linear cavity as well. Herewith, the output linewidth at high powers tends to saturation at a level of 1.8 nm. PMID:26368715

  9. Fiber optics interface for a dye laser oscillator and method

    DOEpatents

    Johnson, Steve A.; Seppala, Lynn G.

    1986-01-01

    A dye laser oscillator in which one light beam is used to pump a continuous tream of dye within a cooperating dye chamber for producing a second, different beam is generally disclosed herein along with a specific arrangement including an optical fiber and a fiber optics interface for directing the pumping beam into the dye chamber. The specific fiber optics interface illustrated includes three cooperating lenses which together image one particular dimension of the pumping beam into the dye chamber from the output end of the optical fiber in order to insure that the dye chamber is properly illuminated by the pumping beam.

  10. Fiber optics interface for a dye laser oscillator and method

    DOEpatents

    Johnson, S.A.; Seppala, L.G.

    1984-06-13

    A dye laser oscillator in which one light beam is used to pump a continuous stream of dye within a cooperating dye chamber for producing a second, different beam is generally disclosed herein along with a specific arrangement including an optical fiber and a fiber optics interface for directing the pumping beam into the dye chamber. The specific fiber optics interface illustrated includes three cooperating lenses which together image one particular dimension of the pumping beam into the dye chamber from the output end of the optical fiber in order to insure that the dye chamber is properly illuminated by the pumping beam.

  11. Tm:germanate Fiber Laser: Tuning And Q-switching

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; Walsh, Brian M.; Reichle, Donald J.; DeYoung, R. J.; Jiang, Shibin

    2007-01-01

    A Tm:germanate fiber laser produced >0.25 mJ/pulse in a 45 ns pulse. It is capable of producing multiple Q-switched pulses from a single p ump pulse. With the addition of a diffraction grating, Tm:germanate f iber lasers produced a wide, but length dependent, tuning range. By s electing the fiber length, the tuning range extends from 1.88 to 2.04 ?m. These traits make Tm:germanate lasers suitable for remote sensin g of water vapor.

  12. Multiplexed multi-longitudinal mode fiber laser sensor.

    PubMed

    Huang, Long; Wang, Peng; Gao, Liang; Zhang, Tingting; Chen, Xiangfei

    2014-10-20

    A multiplexed multi-longitudinal mode fiber laser sensor system is proposed and demonstrated. By incorporating two matched wavelength division multiplexers (WDMs) and a semiconductor optical amplifier (SOA) into a fiber laser cavity, multiwavelength oscillation is established. Each wavelength corresponding to one channel of WDMs contains multi-longitudinal modes. The multiwavelength output of the laser is directed to another WDM which functions as a demultiplexer. By monitoring the longitudinal mode beat frequency generated at photodetectors following the WDM, the sensing information can be demodulated. Preliminary results for multiplexing two sensors measuring strain and temperature are presented to verify the principle of the system. PMID:25401605

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

    PubMed

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

    2009-10-12

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

  14. 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.

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

    PubMed

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

    2015-09-15

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

  16. Fiber laser micro-cutting of stainless steel sheets

    NASA Astrophysics Data System (ADS)

    Baumeister, M.; Dickmann, K.; Hoult, T.

    2006-11-01

    The authors report on laser micro-cutting results for stainless steel foils with the aid of a 100 W fiber laser. This novel laser source combines a high output power in relation to conventional laser sources for micro-processing applications with an excellent beam quality (M2=1.1). Different material thicknesses were evaluated (100 μm to 300 μm). Processing was carried out with cw operation of the laser source, and with nitrogen and oxygen as assisting gases. Besides the high processing rate of oxygen assisted cutting, a better cutting performance in terms of a lower kerf width was obtained.

  17. Stable multi-wavelength fiber laser with single-mode fiber in a Sagnac loop.

    PubMed

    Wang, Pinghe; Wang, Lei; Shi, Guohua; He, Tiejun; Li, Heping; Liu, Yong

    2016-04-20

    In this paper, we propose and experimentally demonstrate a stable multi-wavelength fiber laser at 1.5 μm with single-mode fiber (SMF). The Sagnac loop structure with a 48.6:51.4 coupler and 2 km SMF has an intensity-dependent loss, which contributes to suppress the mode competition in the cavity and leads to a steady multi-wavelength output. In the experiment, five stable lasing wavelengths are obtained with a pump power of 300 mW at 980 nm. The demonstrated multi-wavelength fiber laser has great potential for applications in optical communications and optical sensing systems. PMID:27140108

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  19. Features of infrared ultrabroadband supercontinuum generation under filamentation of femtosecond laser pulses in solid media with various bandgaps

    NASA Astrophysics Data System (ADS)

    Frolov, S. A.; Trunov, V. I.

    2015-12-01

    Recent theoretical and experimental studies show that filamentation of femtosecond pulses in middle infrared range in solids can generate intense supercontinuum (SC) with width of a several octaves. The structure and dynamics of the spectrum formation is different from those observed during filamentation of femtosecond pulses in the near infrared range of the spectrum. With numerical modeling we investigate features of infrared (IR) SC generation in a number of solid-state media transparent in a broad infrared range with various bandgaps, including KBr (7.6 eV), ZnS (3.68 eV) and ZnSe (2.71 eV) for different pump wavelengths. SC formation dynamics is analyzed. With comparison of different media, including one with artificial bandgap, we find that lower bandgap decreases SC bandwidth and filamentation length.

  20. Tunable Fiber Bragg Grating Ring Lasers using Macro Fiber Composite Actuators

    NASA Technical Reports Server (NTRS)

    Geddis, Demetris L.; Allison, Sidney G.; Shams, Qamar A.

    2006-01-01

    The research reported herein includes the fabrication of a tunable optical fiber Bragg grating (FBG) fiber ring laser (FRL)1 from commercially available components as a high-speed alternative tunable laser source for NASA Langley s optical frequency domain reflectometer (OFDR) interrogator, which reads low reflectivity FBG sensors. A Macro-Fiber Composite (MFC) actuator invented at NASA Langley Research Center (LaRC) was selected to tune the laser. MFC actuators use a piezoelectric sheet cut into uniaxially aligned rectangular piezo-fibers surrounded by a polymer matrix and incorporate interdigitated electrodes to deliver electric fields along the length of the piezo-fibers. This configuration enables MFC actuators to produce displacements larger than the original uncut piezoelectric sheet. The FBG filter was sandwiched between two MFC actuators, and when strained, produced approximately 3.62 nm of wavelength shift in the FRL when biasing the MFC actuators from 500 V to 2000 V. This tunability range is comparable to that of other tunable lasers and is adequate for interrogating FBG sensors using OFDR technology. Three different FRL configurations were studied. Configuration A examined the importance of erbium-doped fiber length and output coupling. Configuration B demonstrated the importance of the FBG filter. Configuration C added an output coupler to increase the output power and to isolate the filter. Only configuration C was tuned because it offered the best optical power output of the three configurations. Use of Plastic Optical Fiber (POF) FBG s holds promise for enhanced tunability in future research.

  1. Random fiber laser of POSS solution-filled hollow optical fiber by end pumping

    NASA Astrophysics Data System (ADS)

    Hu, Zhijia; Zheng, Hongjun; Wang, Lijuan; Tian, Xiujie; Wang, Tongxin; Zhang, Qijin; Zou, Gang; Chen, Yang; Zhang, Qun

    2012-09-01

    Random fiber laser is obtained by end pumping a hollow optical fiber (HOF) filled with a dispersive solution of polyhedral oligomeric silsesquioxanes (POSS) nanoparticles and laser dye pyrromethene 597 (PM597) in carbon disulfide (CS2), in which the concentration is 1.5×10-2 M for PM597 and 18.5 wt% for POSS, respectively. It is found that the pump light at the one end of the liquid core optical fiber (LCOF) can pass the whole length of LCOF because the POSS nanoparticles were dispersed in CS2 at a molecular level (1-3 nm) with high stability and without sedimentation. Above the threshold pump energy (˜0.81 mJ) the random fiber laser appears coherent and resonant feedback multimode lasing in the weakly scattering system. For the LCOF containing PM597 with the same concentration and no POSS nanoparticles, there occurs only ASE that can be observed under the same experimental condition.

  2. 954 nm Raman fiber laser with multimode laser diode pumping

    NASA Astrophysics Data System (ADS)

    Zlobina, E. A.; Kablukov, S. I.; Skvortsov, M. I.; Nemov, I. N.; Babin, S. A.

    2016-03-01

    CW Raman fiber laser emitting at 954 nm under direct pumping by a high-power multimode laser diode at 915 nm is demonstrated. A cavity of the laser is formed with 2.5 km-long multimode graded-index fiber and two mirrors: highly reflective fiber Bragg grating (FBG) at one side and normally cleaved fiber end at the other side. The laser generates low-index transverse modes at the Stokes wavelength with output power above 4 W at a slope efficiency above 40%. It is shown that utilization of a narrowband FBG mirror with low reflectivity instead of the cleaved fiber end with Fresnel reflection leads to stronger spectral mode selection, but the generated power is reduced in this case.

  3. Laser fiber migration into the pelvic cavity: A rare complication of endovenous laser ablation.

    PubMed

    Lun, Yu; Shen, Shikai; Wu, Xiaoyu; Jiang, Han; Xin, Shijie; Zhang, Jian

    2015-10-01

    Endovenous laser ablation is an established alternative to surgery with stripping for the treatment of varicose veins. Ecchymoses and pain are frequently reported side effects of endovenous laser ablation. Device-related complications are rare but serious. We describe here an exceptional complication, necessitating an additional surgical procedure to remove a segment of laser fiber that had migrated into the pelvic cavity. Fortunately, severe damage had not occurred. This case highlights the importance of checking the completeness of the guidewire, catheter, and laser fiber after endovenous laser ablation. PMID:24965101

  4. High efficiency Yb:YAG crystalline fiber-waveguide lasers.

    PubMed

    Mu, Xiaodong; Meissner, Stephanie; Meissner, Helmuth; Yu, Anthony W

    2014-11-01

    A laser diode (LD) cladding pumped single-mode 1030 nm laser has been demonstrated, in an adhesive-free bonded 40 μm core Yb:YAG crystalline fiber waveguide (CFW). A laser output power of 13.2 W at a wavelength of 1.03 μm has been achieved, for an input pump power of 39.5 W. The corresponded laser efficiency is 33.4%. The laser beam quality is confirmed to be near diffraction-limited, with a measured M2 = 1.02. A LD core pumped single-clad Yb:YAG CFW laser has also been demonstrated with a top-hat laser beam profile, with a laser output power of 28 W and a slope efficiency of 78%. PMID:25361347

  5. High power tandem-pumped thulium-doped fiber laser.

    PubMed

    Wang, Yao; Yang, Jianlong; Huang, Chongyuan; Luo, Yongfeng; Wang, Shiwei; Tang, Yulong; Xu, Jianqiu

    2015-02-01

    We propose a cascaded tandem pumping technique and show its high power and high efficient operation in the 2-μm wavelength region, opening up a new way to scale the output power of the 2-μm fiber laser to new levels (e.g. 10 kW). Using a 1942 nm Tm(3+) fiber laser as the pump source with the co- (counter-) propagating configuration, the 2020 nm Tm(3+) fiber laser generates 34.68 W (35.15W) of output power with 84.4% (86.3%) optical-to-optical efficiency and 91.7% (92.4%) slope efficiency, with respect to launched pump power. It provides the highest slope efficiency reported for 2-μm Tm(3+)-doped fiber lasers, and the highest output power for all-fiber tandem-pumped 2-μm fiber oscillators. This system fulfills the complete structure of the proposed cascaded tandem pumping technique in the 2-μm wavelength region (~1900 nm → ~1940 nm → ~2020 nm). Numerical analysis is also carried out to show the power scaling capability and efficiency of the cascaded tandem pumping technique. PMID:25836159

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

    PubMed

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

    2015-12-01

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

  7. Femtosecond mode-locked holmium fiber laser pumped by semiconductor disk laser.

    PubMed

    Chamorovskiy, A; Marakulin, A V; Ranta, S; Tavast, M; Rautiainen, J; Leinonen, T; Kurkov, A S; Okhotnikov, O G

    2012-05-01

    We report on a 2085 nm holmium-doped silica fiber laser passively mode-locked by semiconductor saturable absorber mirror and carbon nanotube absorber. The laser, pumped by a 1.16 μm semiconductor disk laser, produces 890 femtosecond pulses with the average power of 46 mW and the repetition rate of 15.7 MHz. PMID:22555700

  8. A 5-mm piezo-scanning fiber device for high speed ultrafast laser microsurgery

    PubMed Central

    Ferhanoglu, Onur; Yildirim, Murat; Subramanian, Kaushik; Ben-Yakar, Adela

    2014-01-01

    Towards developing precise microsurgery tools for the clinic, we previously developed image-guided miniaturized devices using low repetition rate amplified ultrafast lasers for surgery. To improve the speed of tissue removal while reducing device diameter, here we present a new 5-mm diameter device that delivers high-repetition rate laser pulses for high speed ultrafast laser microsurgery. The device consists of an air-core photonic bandgap fiber (PBF) for the delivery of high energy pulses, a piezoelectric tube actuator for fiber scanning, and two aspheric lenses for focusing the light. Its inline optical architecture provides easy alignment and substantial size reduction to 5 mm diameter as compared to our previous MEMS-scanning devices while realizing improved intensity squared (two-photon) lateral and axial resolutions of 1.16 μm and 11.46 μm, respectively. Our study also sheds light on the maximum pulse energies that can be delivered through the air-core PBF and identifies cladding damage at the input facet of the fiber as the limiting factor. We have achieved a maximum energy delivery larger than 700 nJ at 92% coupling efficiency. An in depth analysis reveals how this value is greatly affected by possible slight misalignments of the beam during coupling and the measured small beam pointing fluctuations. In the absence of these imperfections, self-phase modulation becomes the limiting factor for the maximum energy delivery, setting the theoretical upper bound to near 2 μJ for a 1-m long, 7-μm, air-core PBF. Finally, the use of a 300 kHz repetition rate fiber laser enabled rapid ablation of 150 µm x 150 µm area within only 50 ms. Such ablation speeds can now allow the surgeons to translate the surgery device as fast as ~4 mm/s to continuously remove a thin layer of a 150 µm wide tissue. Thanks to a high optical transmission efficiency of the in-line optical architecture of the device and improved resolution, we could successfully perform ablation of

  9. A 5-mm piezo-scanning fiber device for high speed ultrafast laser microsurgery.

    PubMed

    Ferhanoglu, Onur; Yildirim, Murat; Subramanian, Kaushik; Ben-Yakar, Adela

    2014-07-01

    Towards developing precise microsurgery tools for the clinic, we previously developed image-guided miniaturized devices using low repetition rate amplified ultrafast lasers for surgery. To improve the speed of tissue removal while reducing device diameter, here we present a new 5-mm diameter device that delivers high-repetition rate laser pulses for high speed ultrafast laser microsurgery. The device consists of an air-core photonic bandgap fiber (PBF) for the delivery of high energy pulses, a piezoelectric tube actuator for fiber scanning, and two aspheric lenses for focusing the light. Its inline optical architecture provides easy alignment and substantial size reduction to 5 mm diameter as compared to our previous MEMS-scanning devices while realizing improved intensity squared (two-photon) lateral and axial resolutions of 1.16 μm and 11.46 μm, respectively. Our study also sheds light on the maximum pulse energies that can be delivered through the air-core PBF and identifies cladding damage at the input facet of the fiber as the limiting factor. We have achieved a maximum energy delivery larger than 700 nJ at 92% coupling efficiency. An in depth analysis reveals how this value is greatly affected by possible slight misalignments of the beam during coupling and the measured small beam pointing fluctuations. In the absence of these imperfections, self-phase modulation becomes the limiting factor for the maximum energy delivery, setting the theoretical upper bound to near 2 μJ for a 1-m long, 7-μm, air-core PBF. Finally, the use of a 300 kHz repetition rate fiber laser enabled rapid ablation of 150 µm x 150 µm area within only 50 ms. Such ablation speeds can now allow the surgeons to translate the surgery device as fast as ~4 mm/s to continuously remove a thin layer of a 150 µm wide tissue. Thanks to a high optical transmission efficiency of the in-line optical architecture of the device and improved resolution, we could successfully perform ablation of

  10. Cavitation bubble dynamics during thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Hardy, Luke A.; Kennedy, Joshua D.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

    2016-02-01

    The Thulium fiber laser (TFL) is being explored for lithotripsy. TFL parameters differ from standard Holmium:YAG laser in several ways, including smaller fiber delivery, more strongly absorbed wavelength, low pulse energy/high pulse rate operation, and more uniform temporal pulse structure. High speed imaging of cavitation bubbles was performed at 105,000 fps and 10 μm spatial resolution to determine influence of these laser parameters on bubble formation. TFL was operated at 1908 nm with pulse energies of 5-75 mJ, and pulse durations of 200-1000 μs, delivered through 100-μm-core fiber. Cavitation bubble dynamics using Holmium laser at 2100 nm with pulse energies of 200-1000 mJ and pulse duration of 350 μs was studied, for comparison. A single, 500 μs TFL pulse produced a bubble stream extending 1090 +/- 110 μm from fiber tip, and maximum bubble diameters averaged 590 +/- 20 μm (n=4). These observations are consistent with previous studies which reported TFL ablation stallout at working distances < 1.0 mm. TFL bubble dimensions were five times smaller than for Holmium laser due to lower pulse energy, higher water absorption coefficient, and smaller fiber diameter used.

  11. All-fiber 7 × 1 signal combiner for high power fiber lasers.

    PubMed

    Zhou, Hang; Chen, Zilun; Zhou, Xuanfeng; Hou, Jing; Chen, Jinbao

    2015-04-10

    We present an all-fiber 7×1 signal combiner for high power fiber lasers. Through theoretical analysis, the fabrication method is confirmed and the taper length of the fiber bundle is chosen to be 1 cm to ensure a high transmission efficiency of the combiner. Based on the theoretical results, an all-fiber 7×1 signal combiner with high transmission efficiency is fabricated. A capillary with low refractive index is fused around the bundle of signal fibers to make an additional cladding layer. Then the fiber bundle is tapered to match the core of the output fiber and then spliced with the output fiber. The combiner is tested with a 500 W fiber laser and a temperature increase of 13°C/kW without any active cooling is observed in the combiner. The power transmission efficiency is measured to be close to 99% for each input port and the beam quality M2 is around 10. PMID:25967291

  12. Medical Applications Of CO2 Laser Fiber Optics

    NASA Astrophysics Data System (ADS)

    McCord, R. C.

    1981-07-01

    In 1978, Hughes Laboratories reported development of fiber optics that were capable of transmitting CO2 laser energy. These fibers are now being tested for medical applications. Wide ranging medical investigation with CO2 lasers has occurred during the twelve years since the first observations of laser hemostasis. Specialists in ophthalmology, neurosurgery, urology, gynecology, otolaryngology, maxillo-facial/plastic surgery, dermatology, and oncology among others, have explored its use. In principle, all these specialists use CO2 laser radiation at 10.6 microns to thermally destroy diseased tissues. As such, CO2 lasers compare and compete with electrosurgical devices. The fundamental difference between these modalities lies in how they generate heat in treated tissue.

  13. An integrated fiber and stone basket device for use in Thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hutchens, Thomas C.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2014-03-01

    The Thulium fiber laser (TFL) is being explored as an alternative laser lithotripter to the Holmium:YAG laser. The TFL's superior near-single mode beam profile enables higher power transmission through smaller fibers with reduced proximal fiber tip damage. Recent studies have also reported that attaching hollow steel tubing to the distal fiber tip decreases fiber degradation and burn-back without compromising stone ablation rates. However, significant stone retropulsion was observed, which increased with pulse rate. In this study, the hollow steel tip fiber design was integrated with a stone basket to minimize stone retropulsion during ablation. A device was constructed consisting of a 100-μm-core, 140-μm-OD silica fiber outfitted with 5-mm-long stainless steel tubing at the distal tip, and integrated with a 1.3-Fr (0.433-mm-OD) disposable nitinol wire basket, to form an overall 1.9-Fr (0.633-mm- OD) integrated device. This compact design may provide several potential advantages including increased flexibility, higher saline irrigation rates through the ureteroscope working channel, and reduced fiber tip degradation compared to separate fiber and stone basket manipulation. TFL pulse energy of 31.5 mJ with 500 μs pulse duration and pulse rate of 500 Hz was delivered through the integrated fiber/basket device in contact with human uric acid stones, ex vivo. TFL stone ablation rates measured 1.5 +/- 0.2 mg/s, comparable to 1.7 +/- 0.3 mg/s (P > 0.05) using standard bare fiber tips separately with a stone basket. With further development, this device may be useful for minimizing stone retropulsion, thus enabling more efficient TFL lithotripsy at higher pulse rates.

  14. Innovative fiber systems for laser medicine and technology

    NASA Astrophysics Data System (ADS)

    Artiouchenko, Viatcheslav G.; Wojciechowski, Cezar

    2003-10-01

    Development of Polycrystalline Infrared (PIR-) fibers extruded from solid solutions of AgCl/AgBr has opened a new horizon of molecular spectroscopy applications in 4-18 micron range of spectra. PIR-fiber cables and probes could be coupled with a variety of Fourier Transform Infrared (FTIR) spectrometer and Tunable Diode Lasers (TDL), including pig tailing of Mercury Cadmium Tellurium (MCT) detectors. Using these techniques no sample preparation is necessary for PIR-fiber probes have been used to measure reflection and absorption spectra, in situ, in vivo, in real time and even multiplexed. Such PIR-fiber probes have been used for evanescent absorption spectroscopy of malignant tissue and skin surface diagnostics in-vivo, glucose detection in blood as well as crude oil composition analysis, for organic pollution and nuclear waste monitoring. A review of various PIR-fiber applications in medicine, industry and environment control is presented. The synergy of PIR-fibers flexibility with a super high spectral resolution of TDL spectrometers with Δv=10-4cm-1, provides the unique tool for gas analysis, specifically wiht PIR-fibers are coupled as pigtails with MCT-detectors and Pb-salt lasers. Design of multichannel PIR-fiber tailed TDL spectrometer could be used as a portable device for multispectral gas analysis as 1 ppb level of detectivity for various applications in medicine and biotechnology.

  15. Innovative fiber systems for laser medicine and technology

    NASA Astrophysics Data System (ADS)

    Artiouchenko, Viatcheslav G.; Wojciechowski, Cezar

    2004-09-01

    Development of Polycrystalline Infrared (PIR-) fibers extruded from solid solutions of AgCl/AgBr has opened a new horizon of molecular spectroscopy applications in 4 - 18 micron range of spectra. PIR-fiber cables and probes could be coupled with a variety of Fourier Transform Infrared (FTIR) spectrometer and Tunable Diode Lasers (TDL), including pig tailing of Mercury Cadmium Tellurium (MCT) detectors. Using these techniques no sample preparation is necessary for PIR-fiber probes to measure reflection and absorption spectra, in situ, in vivo, in real time and even multiplexed. Such PIR-fiber probes have been used for evanescent absorption spectroscopy of malignant tissue and skin surface diagnostics in-vivo, glucose detection in blood as well as crude oil composition analysis, for organic pollution and nuclear waste monitoring. A review of various PIR-fiber applications in medicine, industry and environment control is presented. The synergy of PIR-fibers flexibility with a super high spectral resolution of TDL spectrometers with Δν=10-4cm-1, provides the unique tool for gas analysis, specifically when PIR-fibers are coupled as pigtails with MCT-detectors and Pb-salt lasers. Design of multichannel PIR-fiber tailed TDL spectrometer could be used as a portable device for multispectral gas analysis at 1 ppb level of detectivity for various applications in medicine and biotechnology.

  16. Femtosecond laser-induced surface structures on carbon fibers.

    PubMed

    Sajzew, Roman; Schröder, Jan; Kunz, Clemens; Engel, Sebastian; Müller, Frank A; Gräf, Stephan

    2015-12-15

    The influence of different polarization states during the generation of periodic nanostructures on the surface of carbon fibers was investigated using a femtosecond laser with a pulse duration τ=300  fs, a wavelength λ=1025  nm, and a peak fluence F=4  J/cm². It was shown that linear polarization results in a well-aligned periodic pattern with different orders of magnitude concerning their period and an alignment parallel and perpendicular to fiber direction, respectively. For circular polarization, both types of uniform laser-induced periodic surface structures (LIPSS) patterns appear simultaneously with different dominance in dependence on the position at the fiber surface. Their orientation was explained by the polarization-dependent absorptivity and the geometrical anisotropy of the carbon fibers. PMID:26670499

  17. Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

    2016-01-01

    Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. 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 greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly 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 into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

  18. Highly efficient mid-infrared dysprosium fiber laser.

    PubMed

    Majewski, Matthew R; Jackson, Stuart D

    2016-05-15

    A new, highly efficient and power scalable pump scheme for 3 μm class fiber lasers is presented. Using the free-running 2.8 μm emission from an Er3+-doped fluoride fiber laser to directly excite the upper laser level of the H13/26→H15/26 transition of the Dy3+ ion, output at 3.04 μm was produced with a record slope efficiency of 51%. Using comparatively long lengths of Dy3+-doped fluoride fiber, a maximum emission wavelength of 3.26 μm was measured. PMID:27176955

  19. Long-term laser frequency stabilization using fiber interferometers.

    PubMed

    Kong, Jia; Lucivero, Vito Giovanni; Jiménez-Martínez, Ricardo; Mitchell, Morgan W

    2015-07-01

    We report long-term laser frequency stabilization using only the target laser and a pair of 5 m fiber interferometers, one as a frequency reference and the second as a sensitive thermometer to stabilize the frequency reference. When used to stabilize a distributed feedback laser at 795 nm, the frequency Allan deviation at 1000 s drops from 5.6 × 10(-8) to 6.9 × 10(-10). The performance equals that of an offset lock employing a second, atom-stabilized laser in the temperature control. PMID:26233353

  20. Sub-micron texturing of silicon wafer with fiber laser

    NASA Astrophysics Data System (ADS)

    Farrokhi, Hamid; Zhou, Wei; Zheng, Hong Yu; Li, Zhongli

    2011-03-01

    Laser texturing is extensively investigated for modifying surface properties. A continuous wave (CW) fiber laser (λ= 1090nm) was used to pattern a silicon wafer surface in ambient and O2 atmosphere respectively. The O2 gas stream was delivered through a coaxial nozzle to the laser spot. Characterization of the patterned features was carried out by surface profiling, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS or EDX), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Formation of laser-induced silicon oxide sub-micron bumps was observed, which were analyzed and shown to cause changes in surface wetability and reflectivity.

  1. Long-term laser frequency stabilization using fiber interferometers

    SciTech Connect

    Kong, Jia; Lucivero, Vito Giovanni; Jiménez-Martínez, Ricardo; Mitchell, Morgan W.

    2015-07-15

    We report long-term laser frequency stabilization using only the target laser and a pair of 5 m fiber interferometers, one as a frequency reference and the second as a sensitive thermometer to stabilize the frequency reference. When used to stabilize a distributed feedback laser at 795 nm, the frequency Allan deviation at 1000 s drops from 5.6 × 10{sup −8} to 6.9 × 10{sup −10}. The performance equals that of an offset lock employing a second, atom-stabilized laser in the temperature control.

  2. Double nanosecond pulses generation in ytterbium fiber laser.

    PubMed

    Veiko, V P; Lednev, V N; Pershin, S M; Samokhvalov, A A; Yakovlev, E B; Zhitenev, I Yu; Kliushin, A N

    2016-06-01

    Double pulse generation mode for nanosecond ytterbium fiber laser was developed. Two sequential 60-200 ns laser pulses with variable delay between them were generated by acousto-optic modulator opening with continuous diode pumping. A custom radio frequency generator was developed to produce two sequential "opening" radio pulses with a delay of 0.2-1 μs. It was demonstrated that double pulse generation did not decrease the average laser power while providing the control over the laser pulse power profile. Surprisingly, a greater peak power in the double pulse mode was observed for the second laser pulse. Laser crater studies and plasma emission measurements revealed an improved efficiency of laser ablation in the double pulse mode. PMID:27370433

  3. Double nanosecond pulses generation in ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Veiko, V. P.; Lednev, V. N.; Pershin, S. M.; Samokhvalov, A. A.; Yakovlev, E. B.; Zhitenev, I. Yu.; Kliushin, A. N.

    2016-06-01

    Double pulse generation mode for nanosecond ytterbium fiber laser was developed. Two sequential 60-200 ns laser pulses with variable delay between them were generated by acousto-optic modulator opening with continuous diode pumping. A custom radio frequency generator was developed to produce two sequential "opening" radio pulses with a delay of 0.2-1 μs. It was demonstrated that double pulse generation did not decrease the average laser power while providing the control over the laser pulse power profile. Surprisingly, a greater peak power in the double pulse mode was observed for the second laser pulse. Laser crater studies and plasma emission measurements revealed an improved efficiency of laser ablation in the double pulse mode.

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

    NASA Astrophysics Data System (ADS)

    Zou, Hui; Lou, Shuqin; Yin, Guolu

    2013-02-01

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

  5. 250 W single-crystal fiber Yb:YAG laser.

    PubMed

    Délen, Xavier; Piehler, Stefan; Didierjean, Julien; Aubry, Nicolas; Voss, Andreas; Ahmed, Marwan Abdou; Graf, Thomas; Balembois, Francois; Georges, Patrick

    2012-07-15

    We demonstrate an Yb:YAG single-crystal fiber laser with 251 W output power in continuous-wave and an optical efficiency of 44%. This performance can be explained by the high overlap between pump and signal beams brought by the pump guiding and by the good thermal management provided by the single-crystal fiber geometry. The oscillator performance with a reflectivity of the output coupler as low as 20% also shows high potential for power amplification. PMID:22825171

  6. Laser-power delivery using chalcogenide glass fibers

    NASA Astrophysics Data System (ADS)

    Hilton, Albert R., Sr.; Hilton, A. R., Jr.; McCord, James; Loretz, Thomas J.

    1997-04-01

    During the last 15 years, numerous programs have been carried out in the U.S., UK, France, Japan, Israel and Russia aimed at providing a flexible chalcogenide glass fiber suited for delivery of power from a carbon dioxide laser emitting at 10.6 micrometer. The success of these programs has been modest at best with output power limited to 10 watts or less. The purpose of this paper is to examine chalcogenide glasses used for fiber from a thermal lensing standpoint.

  7. Amplifier similaritons in a dispersion-mapped fiber laser [Invited

    PubMed Central

    Renninger, William H.; Chong, Andy; Wise, Frank W.

    2011-01-01

    Amplifier similaritons are generated in a dispersion-mapped fiber laser. Output pulse parameters are nearly independent of the net group velocity dispersion (GVD) owing to the strong local nonlinear attraction in the gain fiber, which dictates the pulse evolution. This constitutes a stable mode-locking regime that is capable of generating sub-100-fs pulses over a broad range of anomalous and normal GVD. These features are consistent with numerical simulations. PMID:22109127

  8. Laser-jamming effectiveness analysis of combined-fiber lasers for airborne defense systems.

    PubMed

    Jie, Xu; Shanghong, Zhao; Rui, Hou; Shengbao, Zhan; Lei, Shi; Jili, Wu; Shaoqiang, Fang; Yongjun, Li

    2008-12-20

    The laser-jamming effectiveness of combined fiber lasers for airborne defense systems is analyzed in detail. Our preliminary experimental results are proof of the concept of getting a high-power laser through a beam combination technique. Based on combined fiber lasers, the jamming effectiveness of four-quadrant guidance and imaging guidance systems are evaluated. The simulation results have proved that for a four-quadrant guidance system, the tracking system takes only two seconds to complete tracking, and the new tracking target is the jamming laser; for the imaging guidance system, increasing the power of the jamming laser or the distance between the target and the jamming laser are both efficient ways to achieve a successful laser jamming. PMID:19104536

  9. Gain enhanced L-band optical fiber amplifiers and tunable fiber lasers with erbium-doped fibers

    NASA Astrophysics Data System (ADS)

    Chen, H.; Leblanc, M.; Schinn, G. W.

    2003-02-01

    We report on the experimental investigation of gain enhanced L-band erbium-doped fiber amplifiers (EDFA) by either recycling residual ASE or using a second C-band wavelength pump laser and on the experimental demonstration of L-band tunable erbium-doped fiber ring lasers. We observed that by reflecting ASE from pumped erbium-doped fiber (EDF) the L-band EDFA gain can be enhanced of 2-15 dB depending on amplifier designs. We also studied wavelength and power dependence of second pump laser on the gain enhanced L-band EDFA and found that an optimum wavelength for second pump laser was between 1550 and 1560 nm. Finally, a L-band tunable erbium-doped fiber laser was also constructed in which lazing oscillation was observed closed to 1624 nm by recycling residual ASE. This L-band tunable laser has a line-width of about 300 MHz, an output power of 1 mW, and a signal to source spontaneous emission ratio of 60 dB.

  10. Near and medium infrared optical fiber lasers and emerging applications

    NASA Astrophysics Data System (ADS)

    Prudenzano, F.; Mescia, L.; Allegretti, L.; De Sario, M.; D'Orazio, A.; Di Tommaso, A.; Palmisano, T.; Petruzzelli, V.

    2010-02-01

    Laser cavities emitting in the near and medium infrared wavelength range, made of rare earth doped optical fibers and suitable pairs of integrated mirrors, are used in a large number of applications. Nowadays, the efficient employment of near and medium infrared laser beams is largely widespread in the field of m*aterial processing, surgery, directed energy, remote sensing, spectroscopy, imaging, and so on. In a lot of cases, the high conversion efficiency, the excellent beam quality, the compactness and, the good heat dissipation capability make fiber lasers competitive and attractive with respect to other light sources, such as ion-doped crystal and bulk glass lasers, optical parametric oscillators, semiconductor and gas lasers. The paper aims to recall and/or briefly illustrate a few among the numerous strategies recently followed by research laboratories and industries to obtain laser sources based on rare earth doped optical fibres. A recall on the host materials and the dopants employed for their construction, and the corresponding applications is given, too. Moreover, an example of near infrared (NIR) fiber optic laser development, by employing available on market components is illustrated by underlining the possibility to easily obtain high beam quality.

  11. Laser heated pedestal growth system commissioning and fiber processing

    NASA Astrophysics Data System (ADS)

    Buric, Michael; Yip, M. J.; Chorpening, Ben; Ohodnicki, Paul

    2016-05-01

    A new Laser Heated Pedestal Growth system was designed and fabricated using various aspects of effective legacy designs for the growth of single-crystal high-temperature-compatible optical fibers. The system is heated by a 100-watt, DC driven, CO2 laser with PID power control. Fiber diameter measurements are performed using a telecentric video system which identifies the molten zone and utilizes edge detection algorithms to report fiber-diameter. Beam shaping components include a beam telescope; along with gold-coated reflaxicon, turning, and parabolic focusing mirrors consistent with similar previous systems. The optical system permits melting of sapphire-feedstock up to 1.5mm in diameter for growth. Details regarding operational characteristics are reviewed and properties of single-crystal sapphire fibers produced by the system are evaluated. Aspects of the control algorithm efficacy will be discussed, along with relevant alternatives. Finally, some new techniques for in-situ processing making use of the laser-heating system are discussed. Ex-situ fiber modification and processing are also examined for improvements in fiber properties.

  12. Development of Ho:YLF laser pumped by Tm:fiber laser

    NASA Astrophysics Data System (ADS)

    Mizutani, Kohei; Ishii, Shoken; Itabe, Toshikazu; Asai, Kazuhiro; Sato, Atsushi

    2014-11-01

    We are developing a 2-micron Ho:YLF laser end-pumped by Tm:fiber laser. The oscillator has ring resonator of 3m length. The laser is operated at high repetition rate of 200-5000 Hz in room temperature. The oscillator and amplifier system showed outputs of about 9W in CW and more than 6W in Q-switched operation. This laser will be used for wind and CO2 concentration measurements.

  13. Fiber optic coherent laser radar 3d vision system

    SciTech Connect

    Sebastian, R.L.; Clark, R.B.; Simonson, D.L.

    1994-12-31

    Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  14. Laser to single-mode-fiber coupling: A laboratory guide

    NASA Technical Reports Server (NTRS)

    Ladany, I.

    1992-01-01

    All the information necessary to achieve reasonably efficient coupling of semiconductor lasers to single mode fibers is collected from the literature, reworked when necessary, and presented in a mostly tabular form. Formulas for determining the laser waist radius and the fiber mode radius are given. Imaging relations connecting these values with the object and image distances are given for three types of lenses: ball, hemisphere, and Gradient Index (GRIN). Sources for these lenses are indicated, and a brief discussion is given about ways of reducing feedback effects.

  15. Dissipative solitons in normal-dispersion fiber lasers

    SciTech Connect

    Renninger, W. H.; Chong, A.; Wise, F. W.

    2008-02-15

    Mode-locked fiber lasers in which pulse shaping is based on filtering of a frequency-chirped pulse are analyzed with the cubic-quintic Ginzburg-Landau equation. An exact analytical solution produces a variety of temporal and spectral shapes, which have not been observed in any experimental setting to our knowledge. Experiments agree with the theory over a wide range of parameters. The observed pulses balance gain and loss as well as phase modulations, and thus constitute dissipative temporal solitons. The normal-dispersion fiber laser allows systematic exploration of this class of solitons.

  16. A novel fiber laser development for photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Yavas, Seydi; Aytac-Kipergil, Esra; Arabul, Mustafa U.; Erkol, Hakan; Akcaalan, Onder; Eldeniz, Y. Burak; Ilday, F. Omer; Unlu, Mehmet B.

    2013-03-01

    Photoacoustic microscopy, as an imaging modality, has shown promising results in imaging angiogenesis and cutaneous malignancies like melanoma, revealing systemic diseases including diabetes, hypertension, tracing drug efficiency and assessment of therapy, monitoring healing processes such as wound cicatrization, brain imaging and mapping. Clinically, photoacoustic microscopy is emerging as a capable diagnostic tool. Parameters of lasers used in photoacoustic microscopy, particularly, pulse duration, energy, pulse repetition frequency, and pulse-to-pulse stability affect signal amplitude and quality, data acquisition speed and indirectly, spatial resolution. Lasers used in photoacoustic microscopy are typically Q-switched lasers, low-power laser diodes, and recently, fiber lasers. Significantly, the key parameters cannot be adjusted independently of each other, whereas microvasculature and cellular imaging, e.g., have different requirements. Here, we report an integrated fiber laser system producing nanosecond pulses, covering the spectrum from 600 nm to 1100 nm, developed specifically for photoacoustic excitation. The system comprises of Yb-doped fiber oscillator and amplifier, an acousto-optic modulator and a photonic-crystal fiber to generate supercontinuum. Complete control over the pulse train, including generation of non-uniform pulse trains, is achieved via the AOM through custom-developed field-programmable gate-array electronics. The system is unique in that all the important parameters are adjustable: pulse duration in the range of 1-3 ns, pulse energy up to 10 μJ, repetition rate from 50 kHz to 3 MHz. Different photocoustic imaging probes can be excited with the ultrabroad spectrum. The entire system is fiber-integrated; guided-beam-propagation rendersit misalignment free and largely immune to mechanical perturbations. The laser is robust, low-cost and built using readily available components.

  17. Single-Frequency Narrow Linewidth 2 Micron Fiber Laser

    NASA Technical Reports Server (NTRS)

    Jiang, Shibin (Inventor); Spiegelberg, Christine (Inventor); Luo, Tao (Inventor)

    2006-01-01

    A compact single frequency, single-mode 2 .mu.m fiber laser with narrow linewidth, <100 kHz and preferably <100 kHz, is formed with a low phonon energy glass doped with triply ionized rare-earth thulium and/or holmium oxide and fiber gratings formed in sections of passive silica fiber and fused thereto. Formation of the gratings in passive silica fiber both facilitates splicing to other optical components and reduces noise thus improving linewidth. An increased doping concentration of 0.5 to 15 wt. % for thulium, holmium or mixtures thereof produces adequate gain, hence output power levels for fiber lengths less than 5 cm and preferably less than 3 cm to enable single-frequency operation.

  18. Er/Tm:fiber laser system for coherent Raman microscopy.

    PubMed

    Coluccelli, Nicola; Kumar, Vikas; Cassinerio, Marco; Galzerano, Gianluca; Marangoni, Marco; Cerullo, Giulio

    2014-06-01

    We present a novel architecture for a fiber-based hybrid laser system for coherent Raman microscopy, combining an amplified Er:fiber femtosecond oscillator with a Tm:fiber amplifier boosting the power of the 2-μm portion of a supercontinuum up to 300 mW. This is enough to obtain, by means of nonlinear spectral compression, sub-20-cm(-1) wide pump and Stokes pulses with 2500-3300  cm(-1) frequency detuning and average power at the 100-mW level. Application of this system to stimulated Raman scattering microscopy is discussed. PMID:24875984

  19. Acoustic fiber laser array architecture with reduced optical feedback limitations

    NASA Astrophysics Data System (ADS)

    Molin, S.; Bouffaron, R.; Peigné, A.; Doisy, M.; Mugnier, A.; Pureur, D.

    2014-05-01

    Many sensing applications would benefit of multiplexing a maximum number of Distributed FeedBack Fiber Lasers (DFB FLs) on the same optical fiber. However, in such configurations, some physical mechanisms may impact DFB FLs stable operation, limiting, for instance, the number of DFB FLs spliced on the same fiber and the distance between them. The aim of this experimental study is to investigate the impact of optical feedback on DFB FLs stability. The results of our study are used to propose possible associated architectures.

  20. Laser diode pumped high efficiency Yb:YAG crystalline fiber waveguide lasers

    NASA Astrophysics Data System (ADS)

    Mu, Xiaodong; Meissner, Stephanie; Meissner, Helmuth

    2015-02-01

    Single-clad and double-clad Yb:YAG crystalline fiber waveguides (CFWs) have been prepared with Adhesive-Free Bonding (AFB®) technology. By using a fiber coupled laser diode as pump source, a single-mode laser with near diffraction limited beam quality M2=1.02 has been demonstrated in a double-clad CFW. The laser output power and efficiency are 13.2 W and 34%, respectively. In a single-clad CFW, core pumping was used. The laser output has top-hat beam profile. An output power of 28 W and a slope efficiency of 78% have been achieved respectively.

  1. Regimes of operation states in passively mode-locked fiber soliton ring laser

    NASA Astrophysics Data System (ADS)

    Gong, Y. D.; Shum, P.; Tang, D. Y.; Lu, C.; Guo, X.; Paulose, V.; Man, W. S.; Tam, H. Y.

    2004-06-01

    The principal of passively mode-locked fiber soliton ring lasers is summarized, including its three output operation states: normal soliton, bound-solitons and noise-like pulse. The experimental results of the passively mode-locked fiber soliton ring lasers developed by us are given. Bound-solitons with different discrete separations and three-bound-solitons state have been observed in our fiber laser for the first time. The relationship among three operation states in fiber soliton laser is analyzed.

  2. Remote Fiber Laser Cutting System for Dismantling Glass Melter - 13071

    SciTech Connect

    Mitsui, Takashi; Miura, Noriaki; Oowaki, Katsura; Kawaguchi, Isao; Miura, Yasuhiko; Ino, Tooru

    2013-07-01

    Since 2008, the equipment for dismantling the used glass melter has been developed in High-level Liquid Waste (HLW) Vitrification Facility in the Japanese Rokkasho Reprocessing Plant (RRP). Due to the high radioactivity of the glass melter, the equipment requires a fully-remote operation in the vitrification cell. The remote fiber laser cutting system was adopted as one of the major pieces of equipment. An output power of fiber laser is typically higher than other types of laser and so can provide high-cutting performance. The fiber laser can cut thick stainless steel and Inconel, which are parts of the glass melter such as casings, electrodes and nozzles. As a result, it can make the whole of the dismantling work efficiently done for a shorter period. Various conditions of the cutting test have been evaluated in the process of developing the remote fiber cutting system. In addition, the expected remote operations of the power manipulator with the laser torch have been fully verified and optimized using 3D simulations. (authors)

  3. [INVITED] Multiwavelength operation of erbium-doped fiber-ring laser for temperature measurements

    NASA Astrophysics Data System (ADS)

    Diaz, S.; Lopez-Amo, M.

    2016-04-01

    In this work, simultaneous lasing at up to eight wavelengths is demonstrated in a multi-wavelength erbium-doped fiber ring laser previously reported. This is achieved by introducing a feedback fiber loop in a fiber ring cavity. Eight-wavelength laser emission lines were obtained simultaneously in single-longitudinal mode operation showing a power instability lower than 0.8 dB, and an optical signal-to-noise ratio higher than 42 dB for all the emitted wavelengths. The fiber Bragg gratings give this source the possibility to be also used as sensor-network multiplexing scheme. The application of this system for remote temperature measurements has been demonstrated obtaining good time stability results.

  4. Torsion sensing characteristics of long period fiber gratings fabricated by femtosecond laser in optical fiber

    NASA Astrophysics Data System (ADS)

    Duan, Ji'an; Xie, Zheng; Wang, Cong; Zhou, Jianying; Li, Haitao; Luo, Zhi; Chu, Dongkai; Sun, Xiaoyan

    2016-09-01

    With the alignment of the fiber core systems containing dual-CCDs and high-precision electric displacement platform, twisted long period fiber gratings (T-LPFGs) were fabricated in two different twisted SMF-28 fibers by femtosecond laser. The torsion characteristics of the T-LPFGs were experimentally and theoretical investigated and demonstrated in this study. The achieved torsion sensitivity is 117.4 pm/(rad/m) in the torsion range -105-0 rad/m with a linearity of 0.9995. Experimental results show that compared with the ordinary long period fiber gratings, the resonance wavelength of the gratings presents an opposite symmetrical shift depending on the twisting direction after the applied torsion is removed. In addition, high sensitivity could be obtained, which is very suitable for the applications in the torsion sensor. These results are important for the design of new torsion sensors based on T-LPFGs fabricated by femtosecond laser.

  5. Frequency spacing switchable multiwavelength Brillouin erbium fiber laser utilizing cascaded Brillouin gain fibers.

    PubMed

    Wang, Xiaorui; Yang, Yanfu; Liu, Meng; Yuan, Yijun; Sun, Yunxu; Gu, Yinglong; Yao, Yong

    2016-08-10

    A new hybrid Brillouin erbium fiber laser scheme that employs cascaded multiple Brillouin gain fibers in a ring cavity to realize multiwavelength laser output with switchable frequency spacing is proposed and experimentally investigated. The multiple frequency downshifting processes introduced by multiple stimulated Brillouin scattering (SBS) effects in one round-trip of the cavity make it possible to realize multiwavelength output with frequency spacing that is an integer multiple of the SBS frequency shifting. With two cascaded SBS fibers, the frequency spacing can be switched between single and double SBS frequency shifting by properly adjusting the Brillouin pump power. Multiwavelength outputs with triple or quadruple SBS frequency spacing are also demonstrated by employing three or four SBS gain fibers, respectively. PMID:27534498

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

    PubMed Central

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

    2011-01-01

    For broad applications in biomedical research involving functional dynamics and clinical studies, a photoacoustic microscopy system should be compact, stable, and fast. In this work, we use a fiber laser as the photoacoustic irradiation source to meet these goals. The laser system measures 45×56×13 cm3. The stability of the laser is attributed to the intrinsic optical fiber-based light amplification and output coupling. Its 50-kHz pulse repetition rate enables fast scanning or extensive signal averaging. At the laser wavelength of 1064 nm, the photoacoustic microscope still has enough sensitivity to image small blood vessels while providing high optical absorption contrast between melanin and hemoglobin. Label-free melanoma cells in flowing bovine blood are imaged in vitro, yielding measurements of both cell size and flow speed. PMID:21280901

  7. Ultrafast pulses from a mid-infrared fiber laser.

    PubMed

    Hu, Tomonori; Jackson, Stuart D; Hudson, Darren D

    2015-09-15

    Ultrafast laser pulses at mid-infrared wavelengths (2-20 μm) interact strongly with molecules due to the resonance with their vibration modes. This enables their application in frequency comb-based sensing and laser tissue surgery. Fiber lasers are ideal to achieve these pulses, as they are compact, stable, and efficient. We extend the performance of these lasers with the production of 6.4 kW at a wavelength of 2.8 μm with complete electric field retrieval using frequency-resolved optical gating techniques. Contrary to the problems associated with achieving a high average power, fluoride fibers have now shown the capability of operating in the ultrafast, high-peak-power regime. PMID:26371902

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

    PubMed

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

    2011-01-01

    For broad applications in biomedical research involving functional dynamics and clinical studies, a photoacoustic microscopy system should be compact, stable, and fast. In this work, we use a fiber laser as the photoacoustic irradiation source to meet these goals. The laser system measures 45×56×13 cm3. The stability of the laser is attributed to the intrinsic optical fiber-based light amplification and output coupling. Its 50-kHz pulse repetition rate enables fast scanning or extensive signal averaging. At the laser wavelength of 1064 nm, the photoacoustic microscope still has enough sensitivity to image small blood vessels while providing high optical absorption contrast between melanin and hemoglobin. Label-free melanoma cells in flowing bovine blood are imaged in vitro, yielding measurements of both cell size and flow speed. PMID:21280901

  9. High-brightness power delivery for fiber laser pumping: simulation and measurement of low-NA fiber guiding

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Levy, Moshe; Peleg, Ophir; Rappaport, Noam; Shamay, Moshe; Dahan, Nir; Klumel, Genady; Berk, Yuri; Baskin, Ilya

    2015-02-01

    Fiber laser manufacturers demand high-brightness laser diode pumps delivering optical pump energy in both a compact fiber core and narrow angular content. A pump delivery fiber of a 105 μm core and 0.22 numerical aperture (NA) is typically used, where the fiber NA is under-filled to ease the launch of laser diode emission into the fiber and make the fiber tolerant to bending. At SCD, we have developed multi-emitter fiber-coupled pump modules that deliver 50 W output from a 105 μm, 0.15 NA fiber at 915, 950 and 976 nm wavelengths enabling low-NA power delivery to a customer's fiber laser network. In this work, we address the challenges of coupling and propagating high optical powers from laser diode sources in weakly guiding step-index multimode fibers. We present simulations of light propagation inside the low-NA multimode fiber for different launch conditions and fiber bend diameters using a ray-racing tool and demonstrate how these affect the injection of light into cladding-bounded modes. The mode filling at launch and source NA directly limit the bend radius at which the fiber can be coiled. Experimentally, we measure the fiber bend loss using our 50 W fiber-coupled module and establish a critical bend diameter in agreement with our simulation results. We also employ thermal imaging to investigate fiber heating caused by macro-bends and angled cleaving. The low mode filling of the 0.15 NA fiber by our brightness-enhanced laser diodes allows it to be coiled with diameters down to 70 mm at full operating power despite the low NA and further eliminates the need for mode-stripping at fiber combiners and splices downstream from our pump modules.

  10. Bismuth doped fiber laser and study of unsaturable loss and pump induced absorption in laser performance.

    PubMed

    Kalita, Mridu P; Yoo, Seongwoo; Sahu, Jayanta

    2008-12-01

    A short Bi doped fiber laser operating in the wavelength region of 1160-1179 nm has been demonstrated. The influence of unsaturable loss on laser performance is investigated. Excited state absorption in Bi doped germano-alumino silicate fiber is reported in the 900-1300 nm wavelength range under 800 and 1047 nm pumping. Bi luminescence and fluorescence decay properties under different pumping wavelengths are also investigated. PMID:19065243

  11. Pulsed erbium fiber laser with an acetylene-filled photonic crystal fiber for saturable absorption.

    PubMed

    Marty, Patrick Thomas; Morel, Jacques; Feurer, Thomas

    2011-09-15

    We investigate the dynamics of an erbium-doped fiber ring laser that is equipped with an intracavity hollow core photonic crystal fiber gas cell. The cell is filled with acetylene as a saturable absorber. We observe cw operation at low pressures, Q switching at intermediate pressure levels, and mode locking at high pressures applied. Moreover, we show that the transition from the cw to the pulsed mode may be exploited for sensitive gas detection. PMID:21931393

  12. Laser cutting of carbon fiber reinforced plastics (CFRP) by UV pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Niino, Hiroyuki; Kurosaki, Ryozo

    2011-03-01

    In this paper, we report on a micro-cutting of carbon fiber reinforced plastics (CFRP) by nanosecond-pulsed laser ablation with a diode-pumped solid state UV laser (DPSS UV laser, λ= 355nm). A well-defined cutting of CFRP which were free of debris and thermal-damages around the grooves, were performed by the laser ablation with a multiple-scanpass irradiation method. CFRP is a high strength composite material with a lightweight, and is increasingly being used various applications. UV pulsed laser ablation is suitable for laser cutting process of CFRP materials, which drastically reduces a thermal damage at cut regions.

  13. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Robert J.; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This viewgraph presentation reports on the development of a high power 780 nm laser suitable for space applications of laser cooling. A possible solution is to use frequency doubling of high power 1560 nm telecom lasers. The presentation shows a diagram of the frequency conversion, and a graph of the second harmonic generation in one crystal, and the use of the cascading crystals. Graphs show the second harmonic power as a function of distance between crystals, second harmonic power vs. pump power, tunability of laser systems.

  14. Fiber-optic manipulation of urinary stone phantoms using holmium:YAG and thulium fiber lasers

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard L.; Case, Jason R.; Trammell, Susan R.; Irby, Pierce B.; Fried, Nathaniel M.

    2013-02-01

    Fiber-optic attraction of urinary stones during laser lithotripsy may be exploited to manipulate stone fragments inside the urinary tract without mechanical grasping tools, saving the urologist time and space in the ureteroscope working channel. We compare thulium fiber laser (TFL) high pulse rate/low pulse energy operation to conventional holmium:YAG low pulse rate/high pulse energy operation for fiber-optic suctioning of plaster-of-paris (PoP) stone phantoms. A TFL (wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10 to 350 Hz) and a holmium laser (wavelength of 2120 nm, pulse energy of 35 to 360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz) were tested using 270-μm-core optical fibers. A peak drag speed of ˜2.5 mm/s was measured for both TFL (35 mJ and 150 to 250 Hz) and holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber-optic suctioning of urinary stone phantoms is feasible. TFL operation at high pulse rates/low pulse energies is preferable to holmium operation at low pulse rates/high pulse energies for rapid and smooth stone pulling. With further development, this novel technique may be useful for manipulating stone fragments in the urinary tract.

  15. Research on ytterbium-doped photonic crystal fiber amplifier for the femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Tian, Hongchun; Hou, Zhiyun; Zhang, Sa; Zhou, Guiyao; Xia, Changming; Zhang, Wei; Wu, Jiale; liu, Hongzhan; Zheng, Yan

    2016-01-01

    We report on a single-stage, high-repetition photonic crystal fiber amplifier working at 1030 nm seeded by a femtosecond fiber laser, which generates an output with average power of 2.23 W at a repetition rate of 49.5 MHz and a 3 dB spectral width of 5 nm, corresponding to a pulse energy of 45.2 nJ. After amplification, the spectrum of the femtosecond laser is broadened. A home-made, ytterbium-doped, double-clad photonic crystal fiber fabricated by laser sintering technology combined with a solution doping method with a core diameter of only 24 μm is used as the power amplifier medium. The spectral characteristics as well as the suppression of amplified spontaneous emission are discussed in detail. Experiment confirms that the amplified spontaneous emission becomes negligible with increasing incident seed power and no obvious nonlinear effects arise in this experiment. These results can provide motivation for the application of ytterbium-doped photonic crystal fiber and can provide a potential application for the high-power, all-fiber laser in the future.

  16. Fiber-optic manipulation of urinary stone phantoms using holmium:YAG and thulium fiber lasers.

    PubMed

    Blackmon, Richard L; Case, Jason R; Trammell, Susan R; Irby, Pierce B; Fried, Nathaniel M

    2013-02-01

    Fiber-optic attraction of urinary stones during laser lithotripsy may be exploited to manipulate stone fragments inside the urinary tract without mechanical grasping tools, saving the urologist time and space in the ureteroscope working channel. We compare thulium fiber laser (TFL) high pulse rate/low pulse energy operation to conventional holmium:YAG low pulse rate/high pulse energy operation for fiber-optic suctioning of plaster-of-paris (PoP) stone phantoms. A TFL (wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10 to 350 Hz) and a holmium laser (wavelength of 2120 nm, pulse energy of 35 to 360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz) were tested using 270-μm-core optical fibers. A peak drag speed of ~2.5 mm/s was measured for both TFL (35 mJ and 150 to 250 Hz) and holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber-optic suctioning of urinary stone phantoms is feasible. TFL operation at high pulse rates/low pulse energies is preferable to holmium operation at low pulse rates/high pulse energies for rapid and smooth stone pulling. With further development, this novel technique may be useful for manipulating stone fragments in the urinary tract. PMID:23377013

  17. Thulium fiber laser damage to Nitinol stone baskets

    NASA Astrophysics Data System (ADS)

    Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2015-02-01

    Our laboratory is studying the experimental Thulium fiber laser (TFL) as an alternative lithotripter to clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium laser-induced damage to Nitinol stone baskets have been previously reported. Similarly, this study characterizes TFL induced stone basket damage. A TFL beam with pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rates of 50-500 Hz was delivered through 100-μm-core optical fibers, to a standard 1.9-Fr Nitinol stone basket wire. Stone basket damage was graded as a function of pulse rate, number of pulses, and working distance. Nitinol wire damage decreased with working distance and was non-existent at distances greater than 1.0 mm. In contact mode, 500 pulses delivered at pulse rates >= 200 Hz (<= 2.5 s) were sufficient to cut Nitinol wires. The Thulium fiber laser, operated in low pulse energy and high pulse rate mode, may provide a greater safety margin than standard Holmium laser for lithotripsy, as evidenced by shorter non-contact working distances for stone basket damage than previously reported with Holmium laser.

  18. Advanced experiments with an erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Marques, Paulo V. S.; Marques, Manuel B.; Rosa, Carla C.

    2014-07-01

    This communication describes an optical hands-on fiber laser experiment aimed at advanced college courses. Optical amplifiers and laser sources represent very important optical devices in numerous applications ranging from telecommunications to medicine. The study of advanced photonics experiments is particularly relevant at undergraduate and master level. This paper discusses the implementation of an optical fiber laser made with a cavity built with two tunable Bragg gratings. This scheme allows the students to understand the laser working principles as a function of the laser cavity set-up. One or both of the gratings can be finely tuned in wavelength through applied stress; therefore, the degree of spectral mismatch of the two gratings can be adjusted, effectively changing the cavity feedback. The impact of the cavity conditions on the laser threshold, spectrum and efficiency is analyzed. This experiment assumes that in a previous practice, the students should had already characterized the erbium doped fiber in terms of absorption and fluorescent spectra, and the spectral gain as a function of pump power.

  19. Fiber laser pumped high energy cryogenically cooled Ho:YLF laser

    NASA Astrophysics Data System (ADS)

    Lippert, Espen; Fonnum, Helge; Stenersen, Knut

    2012-09-01

    In this paper we report on a high energy, low repetition rate 2-micron-laser, with high conversion efficiency in terms of output energy per pump power. The laser consists of a Ho3+-doped LiYF4 (YLF) crystal cooled to cryogenic temperatures in an unstable resonator, pumped by a thulium fiber laser. The cooling to 77 K makes Ho:YLF a quasi four level laser system, which greatly enhances the extraction efficiency. We achieved 356 mJ in Q-switched operation at 1 Hz PRF when pumping the laser with 58 W for 36 ms. The high beam quality from the fiber laser and the use of an unstable resonator with a graded reflectivity mirror (GRM) resulted in a high quality laser beam with a M2-value of 1.3.

  20. Templated growth of II-VI semiconductor optical fiber devices and steps towards infrared fiber lasers

    NASA Astrophysics Data System (ADS)

    Sazio, Pier J. A.; Sparks, Justin R.; He, Rongrui; Krishnamurthi, Mahesh; Fitzgibbons, Thomas C.; Chaudhuri, Subhasis; Baril, Neil F.; Peacock, Anna C.; Healy, Noel; Gopalan, Venkatraman; Badding, John V.

    2015-02-01

    ZnSe and other zinc chalcogenide semiconductor materials can be doped with divalent transition metal ions to create a mid-IR laser gain medium with active function in the wavelength range 2 - 5 microns and potentially beyond using frequency conversion. As a step towards fiberized laser devices, we have manufactured ZnSe semiconductor fiber waveguides with low (less than 1dB/cm at 1550nm) optical losses, as well as more complex ternary alloys with ZnSxSe(1-x) stoichiometry to potentially allow for annular heterostructures with effective and low order mode corecladding waveguiding.

  1. Fiber-coupled laser-driven flyer plates system

    SciTech Connect

    Zhao Xinghai; Zhao Xiang; Gao Yang; Shan Guangcun

    2011-04-15

    A system for the launch of hypervelocity flyer plates has been developed and characterized. Laser-driven flyers were launched from the substrate backed aluminum-alumina-aluminum sandwiched films. A laser-induced plasma is used to drive flyers with typical thickness of 5.5 {mu}m and diameters of less than 1 mm, to achieve velocities of a few km/s. These flyer plates have many applications, from micrometeorite simulation to laser ignition. The flyer plates considered here have up to three layers: an ablation layer, to form plasma; an insulating layer; and a final, thicker layer that forms the final flyer plates. This technique was developed aiming at improving the energy efficiency of the system. The kinetic energy of flyers launched with the additional layer was found to be enhanced by a factor of near 2 (up to 30%). The optical fiber delivery system governs the output spatial profile of the laser spot and power capacity. Moreover, a technique for coupling high-power laser pulses into an optical fiber has been developed. This fiber optic system has been successfully used to launch flyer plates, and the surface finishing quality of the fiber was found to be an important factor. Importantly, measurements of the flyer performance including the mean velocities and planarity were made by an optical time-of-arrival technique using an optical fiber array probe, demonstrating the good planarity of the flyer and the achievable average velocity of 1.7 km/s with approaching 1 mm diameter. Finally, the relationship between flyer velocities and incident laser pulses energy was also investigated.

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

    SciTech Connect

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

    1995-01-15

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

  3. Ultra-flat supercontinuum generation in cascaded photonic crystal fiber with picosecond fiber laser pumping

    NASA Astrophysics Data System (ADS)

    Zhang, Huanian; Li, Ping

    2016-08-01

    In this letter, a new method for achieving ultra-flat supercontinuum generation is proposed. A picosecond fiber laser was used as the pump source, in a cascaded photonic crystal fiber, ultra-flat supercontinuum generation spectrum at 3 dB level from 1070 up to 1630 nm is obtained, to our knowledge, the 3 dB bandwidth of 560 nm is the most flat supercontinuum generation obtained in photonic crystal fibers, the results indicated that our method is efficient for achieving ultra-flat supercontinuum, which will promote the technical applications of supercontinuum.

  4. PowerSphere: A Novel Photovoltaic Cavity Converter Using Low Bandgap TPV Cells for Efficient Conversion of High Power Laser Beams to Electricity

    NASA Astrophysics Data System (ADS)

    Ortabasi, Ugur; Friedman, Herbert W.

    2004-11-01

    PowerSphere is a variant of the recently developed Photovoltaic Cavity Converter (PVCC) for High Concentration Photovoltaic applications. Both systems share the benefit of photon recycling in a cavity and have therefore the potential to convert high-density radiant power to electricity at unprecedented efficiencies. Unlike PVCC that is optimized for the full content of the solar spectrum, the PowerSphere is designed to convert the monochromatic beam of a laser efficiently to electricity. The PowerSphere concept introduced here greatly benefits from recent advances in the area of high power, near-IR lasers and advanced bandgap engineering involving `tunable' III-V cells operating in the same range of the spectrum. Given this new scenario the spectral response of such cells can be perfectly tuned to the frequency of a high power laser to achieve conversion efficiencies in excess of 60%. Other key phenomena that allow achieving such high conversion rates are described in the main text of this paper. PowerSphere concept when fully developed can greatly contribute to the advancement of Laser Power Beaming technology for terrestrial, near-space and space applications. The paper explores the performance potential of Laser Power Beaming (LPB) systems using a PowerSphere as a receiver and discusses some of the critical issues that require further studies in this promising area of `Wireless Power Transmission'.

  5. Distributed feedback imprinted electrospun fiber lasers.

    PubMed

    Persano, Luana; Camposeo, Andrea; Del Carro, Pompilio; Fasano, Vito; Moffa, Maria; Manco, Rita; D'Agostino, Stefania; Pisignano, Dario

    2014-10-01

    Imprinted, distributed feedback lasers are demonstrated on individual, active electrospun polymer nanofibers. In addition to advantages related to miniaturization, optical confinement and grating nanopatterning lead to a significant threshold reduction compared to conventional thin-film lasers. The possibility of imprinting arbitrary photonic crystal geometries on electrospun lasing nanofibers opens new opportunities for realizing optical circuits and chips. PMID:25042888

  6. Ultra-long fiber Raman lasers: design considerations

    NASA Astrophysics Data System (ADS)

    Koltchanov, I.; Kroushkov, D. I.; Richter, A.

    2015-03-01

    In frame of the European Marie Currie project GRIFFON [http://astonishgriffon.net/] the usage of a green approach in terms of reduced power consumption and maintenance costs is envisioned for long-span fiber networks. This shall be accomplished by coherent transmission in unrepeatered links (100 km - 350 km) utilizing ultra-long Raman fiber laser (URFL)-based distributed amplification, multi-level modulation formats, and adapted Digital Signal Processing (DSP) algorithms. The URFL uses a cascaded 2-order pumping scheme where two (co- and counter-) ˜ 1365 nm pumps illuminate the fiber. The URFL oscillates at ˜ 1450 nm whereas amplification is provided by stimulated Raman scattering (SRS) of the ˜ 1365 nm pumps and the optical feedback is realized by two Fiber Bragg gratings (FBGs) at the fiber ends reflecting at 1450 nm. The light field at 1450 nm provides amplification for signal waves in the 1550 nm range due to SRS. In this work we present URFL design studies intended to characterize and optimize the power and noise characteristics of the fiber links. We use a bidirectional fiber model describing propagation of the signal, pump and noise powers along the fiber length. From the numerical solution we evaluate the on/off Raman gain and its bandwidth, the signal excursion over the fiber length, OSNR spectra, and the accumulated nonlinearities. To achieve best performance for these characteristics the laser design is optimized with respect to the forward/backward pump powers and wavelengths, input/output signal powers, reflectivity profile of the FBGs and other parameters.

  7. Optical-fiber-coupled optical bistable semiconductor lasers

    SciTech Connect

    Zhing Lichen; Tang Yunxin; Qin Ying; Guo Yili

    1986-12-01

    A compact, low input power optical bistable device, consisting of a photodetector, an optical fiber directional coupler, and a semiconductor laser diode, was presented. The principle is described graphically to explain the observed effects such as hysteresis, differential operational gain and memory functions.

  8. Constant Refractive Index Multi-Core Fiber Laser

    SciTech Connect

    Beach, R J; Feit, M D; Brasure, L D; Payne, S A; Mead, R W; Hayden, J S; Krashkevich, D; Alunni, D A

    2002-03-18

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

  9. Investigation on fiber laser vector hydrophone: theory and experiment

    NASA Astrophysics Data System (ADS)

    Zhang, Wentao; Zhang, Faxiang; Ma, Rui; Li, Fang; Liu, Yuliang

    2010-08-01

    A novel underwater fiber laser vector hydrophone is presented. Theoretical and experimental analyses are carried out to test the performance of the hydrophone, which shows a sensitivity of 25 pm/g and a flat frequency response in the range of 5 Hz~200 Hz are achieved. Field demonstration shows that the vector hydrophone has good directivity.

  10. Frequency chirping in semiconductor-optical fiber ring laser

    SciTech Connect

    Zhang, Jiangping; Ye, Peida )

    1990-01-01

    In this letter, a complete small-signal analysis for frequency chirping in the semiconductor-optical fiber ring laser is presented. It shows that chirp-to-power ratio (CPR) strongly depends on the junction phase shift, the optical coupling, and the phase detuning between two cavities, especially if the modulation frequency is below the gigahertz range. 7 refs.

  11. Laser backlight unit based on a leaky optical fiber

    NASA Astrophysics Data System (ADS)

    Okuda, Yuuto; Onoda, Kousuke; Fujieda, Ichiro

    2012-07-01

    A backlight unit is constructed by laying out an optical fiber on a two-dimensional plane and letting the light leak out in a controlled manner. In experiment, we formed multiple grooves on the surface of a plastic optical fiber by pressing a heated knife edge. The depth of the groove determined the percentage of the optical power leaking out. The optical fiber with multiple grooves was embedded in an acrylic plate with a spiral trench, and a diffuser sheet was placed over it. When we injected laser light into the end of the optical fiber, this configuration successfully worked as an area illuminator. However, the coherent nature of the laser light caused severe speckle noise. We evaluated the speckle contrast under darkness, and it varied from 80% to 23%, depending on the lens aperture used to capture the images of the illuminator. We glued an ultrasound generator to the optical fiber to introduce phase modulation for the light propagating inside the optical fiber. In this way, the speckle contrast was reduced by a factor of seven to four. Under room lighting, the speckle noise was made barely noticeable by turning on the ultrasound generator.

  12. Passively mode-locked single-polarization microstructure fiber laser.

    PubMed

    Ortaç, B; Lecaplain, C; Hideur, A; Schreiber, T; Limpert, J; Tünnermann, A

    2008-02-01

    The generation of high-power and stable ultra-short pulses from a passively mode-locked purely normal dispersion fiber laser is reported using the unique combination of a photonic crystal fiber featuring single-polarization, single-mode, and low nonlinearity with a high modulation depth semiconductor saturable absorber mirror. The environmentally-stable, self-starting fiber laser generates 1.6 W of average power at a repetition rate of 63 MHz, corresponding to a pulse energy of 25 nJ. The emitted pulses are positively chirped with a pulse duration of 3.7 ps. They are compressible down to a near transform-limited duration of 750 fs. Numerical simulations are in good agreement with the experimental results. PMID:18542292

  13. DFB fiber laser hydrophone with band-pass response.

    PubMed

    Zhang, Faxiang; Zhang, Wentao; Li, Fang; Liu, Yuliang

    2011-11-15

    A distributed-feedback fiber laser hydrophone with band-pass response is presented. The design of the hydrophone aims to equalize static pressure and eliminate signal aliasing of high-frequency acoustic components. Theoretical analysis is presented based on electro-acoustic theory. The experimental results agree well with the theory. The measured underwater responses show that the hydrophone has a pressure sensitivity of -170 dB re:pm/μPa over a bandwidth between 100 Hz and 500 Hz. A sensitivity reduction exceeding -35 dB is observed at 2500 Hz. The tested static pressure sensitivity of the hydrophone is -226 dB. The proposed fiber laser hydrophone of this kind is expected to have important application in deep water fiber-optic sonar systems with anti-aliasing, and the understanding gained through this work can be extended to a guide of hydrophone design for required filtering bandwidth. PMID:22089550

  14. Compact all-fiber laser delivering conventional and dissipative solitons.

    PubMed

    Mao, Dong; Liu, Xueming; Han, Dongdong; Lu, Hua

    2013-08-15

    We report the simultaneous generation of conventional soliton (CS) and dissipative soliton (DS) in a mode-locked fiber laser exploiting chirped fiber Bragg grating and four-port circulator. The bandwidth and duration of the CS are 0.28 nm and 15.1 ps, respectively. However, the giant-chirp DS exhibits a quasi-rectangular spectrum with a bandwidth of 9.5 nm. The duration of the output DS is 7.3 ps and can be compressed to 0.55 ps external to the cavity. Our numerical results agree well with the experimental observations. The flexible all-fiber laser can provide three different pulse sources, which is convenient and attractive for practical applications. PMID:24104684

  15. Components for monolithic fiber chirped pulse amplification laser systems

    NASA Astrophysics Data System (ADS)

    Swan, Michael Craig

    The first portion of this work develops techniques for generating femtosecond-pulses from conventional fabry-perot laser diodes using nonlinear-spectral-broadening techniques in Yb-doped positive dispersion fiber ampliers. The approach employed an injection-locked fabry-perot laser diode followed by two stages of nonlinear-spectral-broadening to generate sub-200fs pulses. This thesis demonstrated that a 60ps gain-switched fabry-perot laser-diode can be injection-locked to generate a single-longitudinal-mode pulse and compressed by nonlinear spectral broadening to 4ps. Two problems have been identified that must be resolved before moving forward with this approach. First, gain-switched pulses from a standard diode-laser have a number of characteristics not well suited for producing clean self-phase-modulation-broadened pulses, such as an asymmetric temporal shape, which has a long pulse tail. Second, though parabolic pulse formation occurs for any arbitrary temporal input pulse profile, deviation from the optimum parabolic input results in extensively spectrally modulated self-phase-modulation-broadened pulses. In conclusion, the approach of generating self-phase-modulation-broadened pulses from pulsed laser diodes has to be modified from the initial approach explored in this thesis. The first Yb-doped chirally-coupled-core ber based systems are demonstrated and characterized in the second portion of this work. Robust single-mode performance independent of excitation or any other external mode management techniques have been demonstrated in Yb-doped chirally-coupled-core fibers. Gain and power efficiency characteristics are not compromised in any way in this novel fiber structure up to the 87W maximum power achieved. Both the small signal gain at 1064nm of 30.3dB, and the wavelength dependence of the small signal gain were comparable to currently deployed large-mode-area-fiber technology. The efficiencies of the laser and amplifier were measured to be 75% and 54

  16. Development of pulse laser processing for mounting fiber Bragg grating

    SciTech Connect

    Nishimura, Aikihko; Shimada, Yukihiro; Yonemoto, Yukihiro; Suzuki, Hirokazu; Ishibashi, Hisayoshi

    2012-07-11

    Pulse laser processing has been developed for the application of industrial plants in monitoring and maintenance. Surface cleaning by nano-second laser ablation was demonstrated for decontamination of oxide layers of Cr contained steel. Direct writing by femtosecond processing induced a Bragg grating in optical fiber to make it a seismic sensor for structural health monitoring. Adhesive cement was used to fix the seismic sensor on the surface of reactor coolant pipe material. Pulse laser processing and its related technologies were presented to overcome the severe accidents of nuclear power plants.

  17. Development of pulse laser processing for mounting fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Nishimura, Aikihko; Shimada, Yukihiro; Yonemoto, Yukihiro; Suzuki, Hirokazu; Ishibashi, Hisayoshi

    2012-07-01

    Pulse laser processing has been developed for the application of industrial plants in monitoring and maintenance. Surface cleaning by nano-second laser ablation was demonstrated for decontamination of oxide layers of Cr contained steel. Direct writing by femtosecond processing induced a Bragg grating in optical fiber to make it a seismic sensor for structural health monitoring. Adhesive cement was used to fix the seismic sensor on the surface of reactor coolant pipe material. Pulse laser processing and its related technologies were presented to overcome the severe accidents of nuclear power plants.

  18. Tunable ring laser using a tapered single mode fiber tip.

    PubMed

    Wang, Xiaozhen; Li, Yi; Bao, Xiaoyi

    2009-12-10

    A tunable ring laser using a tapered single mode fiber tip as a bandpass filter has been proposed and demonstrated for the first time to our knowledge. This is a simple and cost-effective tunable source. It is found that the tuning range and bandwidth of the laser are related to the relaxation time of the optical amplifier, the current of the amplifier, and the steepness of the tip shape. The calculations and experimental results show that the laser has a tuning range of 9 nm in the L-band and the spectral linewidth can be varied from 0.06 nm to 0.17 nm. PMID:20011024

  19. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers.

    PubMed

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-01-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers. PMID:27457338

  20. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers

    PubMed Central

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-01-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers. PMID:27457338

  1. Black phosphorus: a two-dimension saturable absorption material for mid-infrared Q-switched and mode-locked fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Luo, Hongyu; Zhai, Bo; Lu, Rongguo; Guo, Zhinan; Zhang, Han; Liu, Yong

    2016-07-01

    Black phosphorus (BP) as a novel class of two-dimension (2D) materials has recently attracted enormous attention as a result of its unique physical and chemical features. The remarkably strong light-matter interaction and tunable direct band-gap at a wide range make it an ideal candidate especially in the mid-infrared wavelength region as the saturable absorber (SA). In this paper, the simple and effective liquid phase exfoliation (LPE) method was used to fabricate BP. By introducing the same BP SA into two specifically designed rare earth ions doped fluoride fiber lasers at mid-infrared wavebands, Q-switching with the pulse energy of 4.93 μJ and mode-locking with the pulse duration of 8.6 ps were obtained, respectively. The operation wavelength of ~2970 nm for generated pulse is the reported longest wavelength for BP SA based fiber lasers.

  2. Highly Efficient Operation of Tm:fiber Laser Pumped Ho:YLF Laser

    NASA Technical Reports Server (NTRS)

    Bai, Yingxin; Petros, M.; Yu, Jirong; Petzar, Paul; Trieu, Bo; Chen, Sam; Lee, Hyung; Singh, U.

    2006-01-01

    A 19 W, TEM(sub 00) mode, Ho:YLF laser pumped by continuous wave Tm:fiber laser has been demonstrated at the room temperature. The slope efficiency and optical-to-optical efficiency are 65% and 55%, respectively.

  3. Coilable single crystals fibers of doped-YAG for high power laser applications

    NASA Astrophysics Data System (ADS)

    Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet; Ribuot, Antoine; Maxwell, Gisele

    2014-05-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They have the advantages of both guiding laser light and matching efficiencies found in bulk crystals, which make them ideal candidates for high-power laser and fiber laser applications. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc.) that will exhibit good wave guiding properties. Direct growth or a combination of growth and cladding experiments are described. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  4. Coilable single crystals fibers of doped-YAG for high power laser applications

    NASA Astrophysics Data System (ADS)

    Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet; Ribuot, Antoine; Maxwell, Gisele

    2014-02-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They have the advantages of both guiding laser light and matching the efficiencies found in bulk crystals, which is making them ideal candidates for high-power laser and fiber laser applications. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc…) that will exhibit good wave guiding properties. Direct growth or a combination of growth and cladding experiments are described. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  5. Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

    NASA Astrophysics Data System (ADS)

    Feng, Liefeng; Yang, Xiufang; Li, Yang; Li, Ding; Wang, Cunda; Yao, Dongsheng; Hu, Xiaodong; Li, Hongru

    2015-04-01

    The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by Ithl and Ithu, as shown in Fig. 2; Ithl is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; Ithu is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (Vj) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at Ithl and Ithu. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.

  6. Synthesis of Ge1-xSnx alloys by ion implantation and pulsed laser melting: Towards a group IV direct bandgap material

    NASA Astrophysics Data System (ADS)

    Tran, Tuan T.; Pastor, David; Gandhi, Hemi H.; Smillie, Lachlan A.; Akey, Austin J.; Aziz, Michael J.; Williams, J. S.

    2016-05-01

    The germanium-tin (Ge1-xSnx) material system is expected to be a direct bandgap group IV semiconductor at a Sn content of 6.5 - 11 at . % . Such Sn concentrations can be realized by non-equilibrium deposition techniques such as molecular beam epitaxy or chemical vapour deposition. In this report, the combination of ion implantation and pulsed laser melting is demonstrated to be an alternative promising method to produce a highly Sn concentrated alloy with a good crystal quality. The structural properties of the alloys such as soluble Sn concentration, strain distribution, and crystal quality have been characterized by Rutherford backscattering spectrometry, Raman spectroscopy, x ray diffraction, and transmission electron microscopy. It is shown that it is possible to produce a high quality alloy with up to 6.2 at . % Sn . The optical properties and electronic band structure have been studied by spectroscopic ellipsometry. The introduction of substitutional Sn into Ge is shown to either induce a splitting between light and heavy hole subbands or lower the conduction band at the Γ valley. Limitations and possible solutions to introducing higher Sn content into Ge that is sufficient for a direct bandgap transition are also discussed.

  7. Large bandgap blueshifts in the InGaP/InAlGaP laser structure using novel strain-induced quantum well intermixing

    NASA Astrophysics Data System (ADS)

    Al-Jabr, A. A.; Majid, M. A.; Alias, M. S.; Anjum, D. H.; Ng, T. K.; Ooi, B. S.

    2016-04-01

    We report on a novel quantum well intermixing (QWI) technique that induces a large degree of bandgap blueshift in the InGaP/InAlGaP laser structure. In this technique, high external compressive strain induced by a thick layer of SiO2 cap with a thickness ≥1 μm was used to enhance QWI in the tensile-strained InGaP/InAlGaP quantum well layer. A bandgap blueshift as large as 200 meV was observed in samples capped with 1-μm SiO2 and annealed at 1000 °C for 120 s. To further enhance the degree of QWI, cycles of annealing steps were applied to the SiO2 cap. Using this method, wavelength tunability over the range of 640 nm to 565 nm (˜250 meV) was demonstrated. Light-emitting diodes emitting at red (628 nm), orange (602 nm), and yellow (585 nm) wavelengths were successfully fabricated on the intermixed samples. Our results show that this new QWI method technique may pave the way for the realization of high-efficiency orange and yellow light-emitting devices based on the InGaP/InAlGaP material system.

  8. Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

    SciTech Connect

    Feng, Liefeng E-mail: lihongru@nankai.edu.cn; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng; Li, Yang; Li, Ding; Hu, Xiaodong; Li, Hongru E-mail: lihongru@nankai.edu.cn

    2015-04-15

    The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I{sub th}{sup l} and I{sub th}{sup u}, as shown in Fig. 2; I{sub th}{sup l} is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I{sub th}{sup u} is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V{sub j}) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I{sub th}{sup l} and I{sub th}{sup u}. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.

  9. Development of fiber-based laser anemometer for SSME application

    NASA Technical Reports Server (NTRS)

    Modarress, Dariush; Fan, Robert

    1989-01-01

    A recent study by Rocketdyne for NASA identified laser anemometry, using a compact optical head, as a feasible diagnostic instrument for the Space Shuttle Main Engine (SSME) Model Verification experiments. Physical Research, Inc. (PRI) is presently under contract from NASA Lewis to develop and deliver such a laser anemometer system. For this application, it is desired to place the laser at a remote distance from the engine, and use single mode polarization preserving fiber optics for the transmission of the laser light to and from the measurement head. Other requirements are given. Analytical and experimental tools are being used to develop the technologies required for the laser anemometer. These include finite element analysis of the optical head and vibration tests for various optical and mechanical components. Design of the optical head and the fiber optic connectors are driven by the temperature and vibration requirements for the measurement environment. Results of the finite element analysis and the vibration tests of the components are included. Conceptual design of the fiber optic launcher and the optical probe has also been complete. Detailed design of the probe as well as the fabrication and assembly of the components is in progress.

  10. 980 nm narrow linewidth Yb-doped phosphate fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Pingxue; Yao, Yifei; Hu, Haowei; Chi, Junjie; Yang, Chun; Zhao, Ziqiang; Zhang, Guangju

    2014-12-01

    A narrow-linewidth ytterbium (Yb)-doped phosphate fiber laser based on fiber Bragg grating (FBG) operating around 980 nm is reported. Two different kinds of cavity are applied to obtain the 980 nm narrow-linewidth output. One kind of the cavity consists of a 0.35 nm broadband lindwidth high-reflection FBG and the Yb-doped phosphate fiber end with 0° angle, which generates a maximum output power of 25 mW. The other kind of resonator is composed of a single mode Yb-doped phosphate fiber and a pair of FBGs. Over 10.7 mW stable continuous wave are obtained with two longitudinal modes at 980 nm. We have given a detailed analysis and discussion for the results.

  11. Fiber laser welding of nickel-based superalloy inconel 718

    NASA Astrophysics Data System (ADS)

    Oshobe, Omudhohwo Emaruke

    Inconel 718 (IN 718) is widely used in applications, such as aircraft and power turbine components. Recently, fiber laser welding has become an attractive joining technique in industry for fabrication and repair of service-damaged components. However, a major limitation in the laser welding of IN 718 is that liquation cracking occurs. In the present work, autogenous fiber laser welding of IN 718 was used to study the effects of welding parameters and different pre-weld heat treatments on liquation cracking. Contrary to previous studies, a dual effect of heat input on cracking is observed. A rarely reported effect of heat input is attributed to process instability. Liquation cracking increases with pre-weld heat treatment temperatures that increase grain size and/or, possibly, intregranular boron segregation. The study shows that pre-weld heat treatment at 950oC can be used for repair welding of IN 718 without significant loss in cracking resistance.

  12. Compact frequency-quadrupled pulsed 1030nm fiber laser

    NASA Astrophysics Data System (ADS)

    McIntosh, Chris; Goldberg, Lew; Cole, Brian; DiLazaro, Tom; Hays, Alan D.

    2016-03-01

    A compact 1030nm fiber laser for ultraviolet generation at 257.5nm is presented. The laser employs a short length of highly-doped, large core (20μm), coiled polarization-maintaining ytterbium-doped double-clad fiber pumped by a wavelength-stabilized 975nm diode. It is passively Q-switched via a Cr4+:YAG saturable absorber and generates 2.4W at 1030nm in a 110μJ pulse train. Lithium triborate (LBO) and beta-barium borate (BBO) are used to achieve 325mW average power at the fourth harmonic. The laser's small form factor, narrow linewidth and modest power consumption are suitable for use in a man-portable ultraviolet Raman explosives detection system.

  13. 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.

  14. High efficiency, high pulse energy fiber laser system

    NASA Astrophysics Data System (ADS)

    Bowers, Mark S.; Henrie, Jason; Garske, Megan; Templeman, Dan; Afzal, Robert

    2013-05-01

    We report a master-oscillator/power-amplifier laser system featuring a polarizing and coilable 40-micron-core Yb-doped photonic crystal fiber as the final-stage amplifier. The laser source generates 3.4 ns pulses at a repetition rate 19 kHz, with maximum pulse energy 1.2 mJ, maximum average power 22.8 W, near diffraction-limited (M2 < 1.1) beam quality, and 20% electrical to optical efficiency in a compact package. This pulsed-fiber laser flight system provides high pulse energy, average power, peak power, diffraction limited beam quality, and high efficiency all in a thermally and mechanically stable compact package.

  15. Frequency doubling of Raman fiber lasers with random distributed feedback.

    PubMed

    Dontsova, E I; Kablukov, S I; Vatnik, I D; Babin, S A

    2016-04-01

    This Letter presents what we believe is the first experimental study of frequency doubling of a Raman fiber laser (RFL) with random distributed feedback (RDFB) in an MgO:PPLN crystal. We compared two laser configurations, each with a half-open cavity. The cavity contained either a broadband Sagnac mirror or a narrowband fiber Bragg grating (FBG). We found that spectral broadening in the studied configurations of the RDFB RFLs differed from that found in a conventional RFL with a linear cavity, as well as from each other. We also compared the second harmonic generation (SHG) efficiency for these three types of lasers. The highest SHG efficiency was obtained for the RDFB RFL with the FBG delivering >100  mW power at 654 nm. PMID:27192256

  16. An all-fiber approach for in-phase supermode phase-locked operation of multicore fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, L.; Schülzgen, A.; Temyanko, V. L.; Li, H.; Moloney, J. V.; Peyghambarian, N.

    2007-02-01

    An all-fiber approach is utilized to phase lock and select the in-phase supermode of compact multicore fiber lasers. Based on the principles of Talbot imaging and waveguide multimode interference, the fundamental supermode is selectively excited within a completely monolithic fiber device. The all-fiber device is constructed by simply fusion splicing passive non-core optical fibers of controlled lengths at both ends of a piece of multicore fiber. Experimental results upon in-house-made 19- and 37-core fibers are demonstrated, which generate output beams with high-brightness far-field intensity distributions. The whole fabricated multicore fiber laser device can in principle be a single fiber chain that is only ~10 cm in length, aligning-free in operation, and robust against environmental disturbance.

  17. YAG-derived fiber for high-power narrow-linewidth fiber lasers

    NASA Astrophysics Data System (ADS)

    Dragic, Peter D.; Liu, Yuh-Shiuan; Ballato, John; Hawkins, Thomas; Foy, Paul

    2012-02-01

    We present experimental and modeling results investigating rare earth-doped (Er and Yb) YAG-derived silica fibers (RYDF) as candidates for use in high-power narrow-linewidth fiber lasers. Fabrication of the RYDFs via a rod-in-tube method, starting from crystalline YAG, and its transformation to the amorphous state is described. Stimulated Brillouin scattering (SBS) suppression results from material properties that cooperate to yield a low Brillouin gain coefficient (BGC), namely reduced photoelastic constant and increased acoustic velocity, mass density, and Brillouin spectral width relative to silica. We find typical BGC values for large-mode-area RYDFs to be around 0.5×10-11 m/W. Utilizing a materials model, these results are extrapolated to compositionally-design further reductions to the BGC, including introducing other co-dopants to the mixture. Finally, we focus on the Yb-doped RYDF (YYDF) and show that it is a good candidate for use in kW-class narrow-linewidth fiber lasers via spectroscopy and amplifier experiments. The RYDFs are found to be very similar to conventional aluminosilicate fibers. We also find that YYDFs offer improved compatibility with phase modulating the laser for further increases in the SBS threshold. Using novel fiber fabrication methods with less-common and low-silica materials can lead to promising glass recipes with ultra-low intrinsic BGCs.

  18. Highly efficient fiber coupling of laser diode bars with > 50% electro-optical efficiency out of the fiber core

    NASA Astrophysics Data System (ADS)

    Fornahl, Udo; Revermann, Markus; Meinschien, Jens

    2008-02-01

    Fiber-coupled diode lasers have become an established source for many industrial applications due to their high wall-plug efficiency, minimal maintenance and cost per watt. To decrease system size and cost for cooler and driver, high coupling efficiencies have become more and more important. Recent developments in broad area laser diode bars (BALB) and beam shaping systems with micro-optical components are leading to new highly efficient fiber coupling. We present newly developed high power diode laser modules which are performing at outstanding efficiencies with smallest package design. The combination of recently designed laser diode bars on passive heat sinks and optimized micro-optics results in laser modules with up to 60W out of a 200μm fiber with a 0.22 NA and > 50% electro-optical efficiency out of the fiber core, based on only one laser diode bar. The applications for such laser diode modules range from pumping of fiber lasers and amplifiers, over materials processing to medical applications. The presentation of the technology will show a path to scale high-brightness laser systems to higher power levels and efficiencies. The combination of different coupling techniques will allow laser modules with 100W out of 100μm fiber core up to 1.6kW out of 400μm fiber core with electro-optical efficiencies of > 45%.

  19. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser

    PubMed Central

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-01-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900–2000 nm. PMID:27416893

  20. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser

    NASA Astrophysics Data System (ADS)

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-07-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900–2000 nm.

  1. High-power ultralong-wavelength Tm-doped silica fiber laser cladding-pumped with a random distributed feedback fiber laser.

    PubMed

    Jin, Xiaoxi; Du, Xueyuan; Wang, Xiong; Zhou, Pu; Zhang, Hanwei; Wang, Xiaolin; Liu, Zejin

    2016-01-01

    We demonstrated a high-power ultralong-wavelength Tm-doped silica fiber laser operating at 2153 nm with the output power exceeding 18 W and the slope efficiency of 25.5%. A random distributed feedback fiber laser with the center wavelength of 1173 nm was employed as pump source of Tm-doped fiber laser for the first time. No amplified spontaneous emissions or parasitic oscillations were observed when the maximum output power reached, which indicates that employing 1173 nm random distributed feedback fiber laser as pump laser is a feasible and promising scheme to achieve high-power emission of long-wavelength Tm-doped fiber laser. The output power of this Tm-doped fiber laser could be further improved by optimizing the length of active fiber, reflectivity of FBGs, increasing optical efficiency of pump laser and using better temperature management. We also compared the operation of 2153 nm Tm-doped fiber lasers pumped with 793 nm laser diodes, and the maximum output powers were limited to ~2 W by strong amplified spontaneous emission and parasitic oscillation in the range of 1900-2000 nm. PMID:27416893

  2. Laser-diode pumped glass-clad Ti:sapphire crystal fiber laser.

    PubMed

    Wang, Shih-Chang; Hsu, Chun-Yang; Yang, Tzu-Te; Jheng, Dong-Yo; Yang, Teng-I; Ho, Tuan-Shu; Huang, Sheng-Lung

    2016-07-15

    Efficient glass-clad crystal fiber (CF) lasers were demonstrated using a Ti:sapphire crystalline core as the gain medium. With a core diameter of 18 μm, the laser diode (LD) pump source can be effectively coupled and guided throughout the crystal fiber for a low threshold and high slope efficiency laser operation. The advantage of high heat dissipation efficiency of the fiber structure can be derived from the low core temperature rising measurement (i.e., 17 K/W) with passive cooling. At an output transmittance of 23%, the lowest absorbed threshold of 118.2 mW and highest slope efficiency of 29.6% were achieved, with linear laser polarization. PMID:27420499

  3. Low-threshold wavelength-switchable fiber laser based on few-mode fiber Bragg grating

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    We propose a backward-pump transverse mode fiber laser to generate optical beams based on few-mode fiber Bragg grating. The grating as a transverse mode filter possesses several reflection peaks by adjusting the core-offset. The transverse mode fiber laser operates at extremely low thresholds which are about 20, 16.5 and 16 mW corresponding to different operation wavelengths of 1560.98, 1562.32 and 1563.76 nm, respectively. The optical signal to noise ratios are about 72, 75.5 and 75.8 dB, when the pump power is fixed at 100 mW, respectively. The effectively exciting modes corresponding to each reflection peak interfere with each other. Different optical beams can be achieved by changing the operating wavelength or changing the state of PC. The device maybe find its applications such as sensing, transporting or manipulating microscopic particles.

  4. Environmentally stable high-power soliton fiber lasers that use chirped fiber Bragg gratings

    SciTech Connect

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

    1995-08-01

    Environmentally stable high-power erbium fiber soliton lasers are constructed by Kerr or carrier-type mode locking. We obtain high-energy pulses by using relatively short fiber lengths and providing large amounts of negative dispersion with chirped fiber Bragg gratings. The pulse energies and widths generated with both types of soliton laser are found to scale with the square root of the cavity dispersion. Kerr mode locking requires pulses with an approximately three times higher nonlinear phase shift in the cavity than carrier mode locking, which leads to the generation of slightly shorter pulses with as much as seven times higher pulse energies at the mode-locking threshold. {copyright} {ital 1995} {ital Optical} {ital Society} {ital of} {ital America}.

  5. Sub-300 femtosecond soliton tunable fiber laser with all-anomalous dispersion passively mode locked by black phosphorus.

    PubMed

    Chen, Yu; Chen, Shuqing; Liu, Jun; Gao, Yanxia; Zhang, Wenjing

    2016-06-13

    By using evanescent field optical deposition method, we had successfully fabricated an effective optoelectronic device based on multi-layer black phosphorus (BP), which is been heavily investigating 2 dimensional (2D) semiconducting material with similar structure as graphene and thickness dependent direct band-gap. By placing this BP-based optoelectronic device inside a highly compact all-anomalous dispersion fiber laser cavity, stable passive mode-locking operation could be ensured and eventually a record 280 fs transmission limited soliton pulse with tunable central wavelength had been obtained through finely tailoring the cavity length. Other operation states, like bound soliton and noise-like state, had also been observed as well. This work demonstrates the enormous potential of BP for ultra-short pulse generation as an effective optoelectronic device. PMID:27410348

  6. All-fiber nonlinearity- and dispersion-managed dissipative soliton nanotube mode-locked laser

    SciTech Connect

    Zhang, Z.; Popa, D. Wittwer, V. J.; Milana, S.; Hasan, T.; Jiang, Z.; Ferrari, A. C.; Ilday, F. Ö.

    2015-12-14

    We report dissipative soliton generation from an Yb-doped all-fiber nonlinearity- and dispersion-managed nanotube mode-locked laser. A simple all-fiber ring cavity exploits a photonic crystal fiber for both nonlinearity enhancement and dispersion compensation. The laser generates stable dissipative solitons with large linear chirp in the net normal dispersion regime. Pulses that are 8.7 ps long are externally compressed to 118 fs, outperforming current nanotube-based Yb-doped fiber laser designs.

  7. Chalcogenide fiber for mid-infrared transmission and generation of laser source

    NASA Astrophysics Data System (ADS)

    Chenard, Francois; Kuis, Robinson A.

    2010-04-01

    Chalcogenide glass fibers are the best candidates for mid-infrared transmission. Their low optical losses and high-power damage threshold are enabling numerous applications: laser power delivery, chemical sensing and imaging. Furthermore, chalcogenide glass fibers are best candidates for demonstrating rare-earth doped fiber lasers and supercontinuum sources in the mid-infrared. The latest results towards the creation of a 4.5 micron fiber laser and a broadband (2-5 micron) supercontinuum source are presented.

  8. Influence of cooling on a bismuth-doped fiber laser and amplifier performance.

    PubMed

    Kalita, Mridu P; Yoo, Seongwoo; Sahu, Jayanta K

    2009-11-01

    We characterize bismuth-doped fibers under different excitation wavelengths. The fiber laser performance at 1179 nm was investigated, incorporating different cooling arrangements. Effective heat extraction can reduce the temperature-dependent unsaturable loss in fiber, resulting in increased laser performance. The operation of a bismuth-doped fiber amplifier at 1179 nm, at both low and high input signals, is also examined. The amplifier efficiency and the saturation power both depend on effective fiber cooling. PMID:19881653

  9. Thulium fiber laser lithotripsy in an in vitro ureter model.

    PubMed

    Hardy, Luke A; Wilson, Christopher R; Irby, Pierce B; Fried, Nathaniel M

    2014-12-01

    Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/ min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy. PMID:25518001

  10. Thulium fiber laser lithotripsy in an in vitro ureter model

    NASA Astrophysics Data System (ADS)

    Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

    2014-12-01

    Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ=2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  12. Reflection Effects in Multimode Fiber Systems Utilizing Laser Transmitters

    NASA Technical Reports Server (NTRS)

    Bates, Harry E.

    1991-01-01

    A number of optical communication lines are now in use at NASA-Kennedy for the transmission of voice, computer data, and video signals. Now, all of these channels use a single carrier wavelength centered near 1300 or 1550 nm. Engineering tests in the past have given indications of the growth of systematic and random noise in the RF spectrum of a fiber network as the number of connector pairs is increased. This noise seems to occur when a laser transmitter is used instead of a LED. It has been suggested that the noise is caused by back reflections created at connector fiber interfaces. Experiments were performed to explore the effect of reflection on the transmitting laser under conditions of reflective feedback. This effort included computer integration of some of the instrumentation in the fiber optic lab using the Lab View software recently acquired by the lab group. The main goal was to interface the Anritsu Optical and RF spectrum analyzers to the MacIntosh II computer so that laser spectra and network RF spectra could be simultaneously and rapidly acquired in a form convenient for analysis. Both single and multimode fiber is installed at Kennedy. Since most are multimode, this effort concentrated on multimode systems.

  13. Developing high energy dissipative soliton fiber lasers at 2 micron

    PubMed Central

    Huang, Chongyuan; Wang, Cong; Shang, Wei; Yang, Nan; Tang, Yulong; Xu, Jianqiu

    2015-01-01

    While the recent discovered new mode-locking mechanism - dissipative soliton - has successfully improved the pulse energy of 1 μm and 1.5 μm fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy at 2 μm due to the anomalous dispersion of the gain fiber. After analyzing the intracavity pulse dynamics, we propose that the gain fiber should be condensed to short lengths in order to generate high energy pulse at 2 μm. Numerical simulation predicts the existence of stable 2 μm dissipative soliton solutions with pulse energy over 10 nJ, comparable to that achieved in the 1 μm and 1.5 μm regimes. Experimental operation confirms the validity of the proposal. These results will advance our understanding of mode-locked fiber lasers at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media. PMID:26348563

  14. Developing high energy dissipative soliton fiber lasers at 2 micron

    NASA Astrophysics Data System (ADS)

    Huang, Chongyuan; Wang, Cong; Shang, Wei; Yang, Nan; Tang, Yulong; Xu, Jianqiu

    2015-09-01

    While the recent discovered new mode-locking mechanism - dissipative soliton - has successfully improved the pulse energy of 1 μm and 1.5 μm fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy at 2 μm due to the anomalous dispersion of the gain fiber. After analyzing the intracavity pulse dynamics, we propose that the gain fiber should be condensed to short lengths in order to generate high energy pulse at 2 μm. Numerical simulation predicts the existence of stable 2 μm dissipative soliton solutions with pulse energy over 10 nJ, comparable to that achieved in the 1 μm and 1.5 μm regimes. Experimental operation confirms the validity of the proposal. These results will advance our understanding of mode-locked fiber lasers at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media.

  15. Developing high energy dissipative soliton fiber lasers at 2 micron.

    PubMed

    Huang, Chongyuan; Wang, Cong; Shang, Wei; Yang, Nan; Tang, Yulong; Xu, Jianqiu

    2015-01-01

    While the recent discovered new mode-locking mechanism--dissipative soliton--has successfully improved the pulse energy of 1 μm and 1.5 μm fiber lasers to tens of nanojoules, it is still hard to scale the pulse energy at 2 μm due to the anomalous dispersion of the gain fiber. After analyzing the intracavity pulse dynamics, we propose that the gain fiber should be condensed to short lengths in order to generate high energy pulse at 2 μm. Numerical simulation predicts the existence of stable 2 μm dissipative soliton solutions with pulse energy over 10 nJ, comparable to that achieved in the 1 μm and 1.5 μm regimes. Experimental operation confirms the validity of the proposal. These results will advance our understanding of mode-locked fiber lasers at different wavelengths and lay an important step in achieving high energy ultrafast laser pulses from anomalous dispersion gain media. PMID:26348563

  16. Modeling and measurement of ytterbium fiber laser generation spectrum

    NASA Astrophysics Data System (ADS)

    Kablukov, Sergey I.; Zlobina, Ekaterina A.; Podivilov, Evgeniy V.; Babin, Sergey A.

    2012-06-01

    A generation spectrum of a fiber laser becomes broader with increasing generation power. The spectra are rather narrow at low power and become comparable with fiber Bragg gratings (FBG) width at high power. It has been shown that the spectral broadening of a fiber laser can be described analytically if the generation spectrum is much narrower than the FBG width. The developed theory has been compared with experiment. Double clad Yb-doped fiber laser of up to 10 W output power is used in the experiment. Scanning Fabry-Perot interferometer with resolution down to 1.2 pm is applied for accurate spectral measurements. At power level less then 1 W a self-sustained pulsation regime accompanied by a narrow-line self-sweeping is observed. At higher power a quasi-CW generation regime with multiple longitudinal modes is established. Investigation of the regime shows linear increase of the generation width with generation power growth. Slope of the dependence has excellent agreement with the theory, but an additive quantity should be added to describe an absolute value that makes significant contribution at low powers. It has been shown that at low powers a spatial hole burning has to be considered. Theoretical model describing the hole burning effect for multimode cw generation is also developed. After inclusion of the hole burning effect the model starts to agree quantitatively with the linewidth measurements both at low and high powers.

  17. High-brightness 9xxnm fiber coupled diode lasers

    NASA Astrophysics Data System (ADS)

    Liu, Rui; Jiang, Xiaochen; Yang, Thomas; He, Xiaoguang; Gao, Yanyan; Zhu, Jing; Zhang, Tujia; Guo, Weirong; Wang, Baohua; Guo, Zhijie; Zhang, Luyan; Chen, Louisa

    2015-03-01

    We developed a high brightness fiber coupled diode laser module providing more than 140W output power from a 105μm NA 0.15 fiber at the wavelength of 915nm.The high brightness module has an electrical to optical efficiency better than 45% and power enclosure more than 90% within NA 0.13. It is based on multi-single emitters using optical and polarization beam combining and fiber coupling technique. With the similar technology, over 100W of optical power into a 105μm NA 0.15 fiber at 976nm is also achieved which can be compatible with the volume Bragg gratings to receive narrow and stabilized spectral linewidth. The light within NA 0.12 is approximately 92%. The reliability test data of single and multiple single emitter laser module under high optical load are also presented and analyzed using a reliability model with an emitting aperture optimized for coupling into 105μm core fiber. The total MTTF shows exceeding 100,000 hours within 60% confidence level. The packaging processes and optical design are ready for commercial volume production.

  18. Femtosecond laser inscription of asymmetric directional couplers for in-fiber optical taps and fiber cladding photonics.

    PubMed

    Grenier, Jason R; Fernandes, Luís A; Herman, Peter R

    2015-06-29

    Precise alignment of femtosecond laser tracks in standard single mode optical fiber is shown to enable controllable optical tapping of the fiber core waveguide light with fiber cladding photonic circuits. Asymmetric directional couplers are presented with tunable coupling ratios up to 62% and bandwidths up to 300 nm at telecommunication wavelengths. Real-time fiber monitoring during laser writing permitted a means of controlling the coupler length to compensate for micron-scale alignment errors and to facilitate tailored design of coupling ratio, spectral bandwidth and polarization properties. Laser induced waveguide birefringence was harnessed for polarization dependent coupling that led to the formation of in-fiber polarization-selective taps with 32 dB extinction ratio. This technology enables the interconnection of light propagating in pre-existing waveguides with laser-formed devices, thereby opening a new practical direction for the three-dimensional integration of optical devices in the cladding of optical fibers and planar lightwave circuits. PMID:26191688

  19. Fiber laser welding of nickel based superalloy Rene 77

    NASA Astrophysics Data System (ADS)

    Janicki, Damian M.

    2013-01-01

    The study of laser bead-on-plate welding of nickel based superalloy Rene 77 using single mode high power fiber laser has been undertaken to determine the effect of process parameters, such as laser power, welding speed and laser beam defocusing, on the weld geometry and quality. Non-porous and crack-free welds can be achieved for a relatively wide range of fiber laser welding parameters. The welding speed has a major effect on the weld aspect ratio. The laser beam defocusing significantly affects the weld bead geometry, the stability of the keyhole and pore formation. The transition from keyhole mode to conduction mode welding occurs between focal point position +2.0 mm and +4.0 mm. The high porosity was observed at the focal point position of +2.0 mm. The heat input higher than18 J/mm results to hot cracking in the heat affected zone (HAZ). Moreover, it was found that the welds with the weld aspect ratio higher than 1.5 contain cracks, which propagate from the HAZ into the weld metal.

  20. Thulium fiber laser-pumped mid-IR OPO

    NASA Astrophysics Data System (ADS)

    Creeden, Daniel; Jiang, Min; Budni, Peter A.; Ketteridge, Peter A.; Setzler, Scott D.; Young, York E.; McCarthy, John C.; Schunemann, Peter G.; Pollak, Thomas M.; Tayebati, Parviz; Chicklis, Evan P.

    2008-04-01

    Fiber lasers are advancing rapidly due to their ability to generate stable, efficient, and diffraction-limited beams with significant peak and average powers. This is of particular interest as fibers provide an ideal pump source for driving parametric processes. Most nonlinear optical crystals which provide phase-matching to the mid-IR at commercially available fiber pump wavelengths suffer from high absorption above 4μm, resulting in low conversion efficiencies in the 4-5μm spectral region. The nonlinear optical crystals which combine low absorption in this same spectral region with high nonlinear gain require pumping at longer wavelengths (typically >1.9μm). In this paper, we report a novel mid-IR OPO pumped by a pulsed thulium-doped fiber laser operating at 2-microns. The eyesafe thulium-fiber pump laser generates >3W of average power at >30kHz repetition rate with 15-30ns pulses in a near diffraction-limited beam. The ZnGeP II (ZGP) OPO produces tunable mid-IR output power in the 3.4-3.99μm (signal) and the 4.0-4.7μm (idler) spectral regions in both singly resonant (SRO) and doubly resonant (DRO) formats. The highest mid-IR output power achieved from this system was 800mW with 20% conversion efficiency at 40kHz. In a separate experiment, the 3W of 2-micron light was further amplified to the 20W level. This amplified output was also used to pump a ZGP OPO, resulting in 2W of output power in the mid-IR. To our knowledge, these are the first demonstrations of a fiber-pumped ZGP OPO.

  1. High-brightness 800nm fiber-coupled laser diodes

    NASA Astrophysics Data System (ADS)

    Berk, Yuri; Levy, Moshe; Rappaport, Noam; Tessler, Renana; Peleg, Ophir; Shamay, Moshe; Yanson, Dan; Klumel, Genadi; Dahan, Nir; Baskin, Ilya; Shkedi, Lior

    2014-03-01

    Fiber-coupled laser diodes have become essential sources for fiber laser pumping and direct energy applications. Single emitters offer reliable multi-watt output power from a 100 m lateral emission aperture. By their combination and fiber coupling, pump powers up to 100 W can be achieved from a low-NA fiber pigtail. Whilst in the 9xx nm spectral range the single emitter technology is very mature with <10W output per chip, at 800nm the reliable output power from a single emitter is limited to 4 W - 5 W. Consequently, commercially available fiber coupled modules only deliver 5W - 15W at around 800nm, almost an order of magnitude down from the 9xx range pumps. To bridge this gap, we report our advancement in the brightness and reliability of 800nm single emitters. By optimizing the wafer structure, laser cavity and facet passivation process we have demonstrated QCW device operation up to 19W limited by catastrophic optical damage to the 100 μm aperture. In CW operation, the devices reach 14 W output followed by a reversible thermal rollover and a complete device shutdown at high currents, with the performance fully rebounded after cooling. We also report the beam properties of our 800nm single emitters and provide a comparative analysis with the 9xx nm single emitter family. Pump modules integrating several of these emitters with a 105 μm / 0.15 NA delivery fiber reach 35W in CW at 808 nm. We discuss the key opto-mechanical parameters that will enable further brightness scaling of multi-emitter pump modules.

  2. 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.

  3. Laser angioplasty with lensed fibers and a holmium:YAG laser in iliac artery occlusions

    NASA Astrophysics Data System (ADS)

    White, Christopher J.; Ramee, Stephen R.; Mesa, Juan E.; Collins, Tyrone J.; Kotmel, Robert; Godfrey, Maureen A.

    1991-05-01

    Holmium-YAG (2.1 (mu) ) laser recanalization was attempted in 10 totally occluded miniature swine iliac arteries using a lensed fiber delivery system. The iliac artery occlusions were created in a Yucatan miniature swine model of atherosclerosis by means of a high cholesterol diet and balloon endothelial denudation. In order to increase the spot size, a spherical silica lens was attached to the distal end of a 300 micrometers core diameter silica optical fiber. The holmium-YAG laser was operated in the free-running mode with 250 microsecond(s) ec pulses at 4 Hz. The energy delivered was 225 mJ per pulse for the 1.0 mm lensed fiber and 200 mJ per pulse for the 1.3 mm lensed fiber. Laser energy was delivered in 2 to 5 second bursts. Successful recanalization was achieved in all 10 arteries attempted without perforation of the arterial wall. The average length of the occlusions was 5.0 +/- 1.8 cm. Following successful laser recanalization significant stenoses (>50%) remained in all of the arteries as judged by angiography. In conclusion, the lensed fibers coupled to the pulsed holmium-YAG laser were safe and effective in recanalizing these difficult lesions in relatively straight iliac arteries. There is potential clinical utility for this system as an adjunct to balloon angioplasty in patients with lesions which are unable to be crossed with guidewires.

  4. A novel laser angioplasty guided hollow fiber using mid-infrared laser

    NASA Astrophysics Data System (ADS)

    Yoshihashi-Suzuki, Sachiko; Yamada, Shinya; Sato, Izuru; Awazu, Kunio

    2006-02-01

    We have proposed selective removal of cholesterol ester by infrared laser of wavelength with 5.75 μm irradiation; the wavelength of 5.75 μm correspond with the ester bond C=O stretching vibration. The flexible laser guiding line and a compact light source are required for our proposal. We used a compact mid-infrared tunable laser by difference frequency generation; DFG laser was developed for substitute light source of free electron laser. In the present work, first, we have developed hollow optical fiber with a diamond lens-tip to deliver DFG laser in the blood vessel and evaluated the transmission of DFG laser from 5.5 μm to 7.5 μm. The transmission of 5.75 μm is about 65%, the DFG beam was focused on the tip of fiber by diamond lens-tip. Secondly, we performed the selective removal experiment of cholesterol ester using the hollow optical fiber with diamond lens-tip and DFG laser. The sample used a two layer model, cholesterol oleate and gelatin. The cholesterol oleate was decomposed by 5.75 μm DFG irradiation with 3.8 W/cm2.

  5. Polarization properties of fiber lasers with twist-induced circular birefringence

    SciTech Connect

    Kim, Ho Young; Lee, El Hang Kim, Byoung Yoon

    1997-09-01

    We have experimentally observed and theoretically analyzed the polarization properties of fiber lasers with twist-induced birefringence. Twisting a fiber induces the circular birefringence of a fiber laser cavity, and this birefringence reduces the effects of intrinsic linear birefringence on the polarization properties of fiber lasers. The frequencies of their polarization eigenmodes coincide with each other gradually as the twist rate increases, and the directions of polarization eigenmodes deviate from the birefringence axis at a much larger twist rate than the magnitude of intrinsic linear birefringence. We describe the successful experimental results for Nd and Er fiber lasers. {copyright} 1997 Optical Society of America

  6. Regenerated distributed Bragg reflector fiber lasers for high-temperature operation.

    PubMed

    Chen, Rongzhang; Yan, Aidong; Li, Mingshan; Chen, Tong; Wang, Qingqing; Canning, John; Cook, Kevin; Chen, Kevin P

    2013-07-15

    This Letter presents distributed Bragg reflector (DBR) fiber lasers for high-temperature operation at 750°C. Thermally regenerated fiber gratings were used as the feedback elements to construct an erbium-doped DBR fiber laser. The output power of the fiber laser can reach 1 mW at all operating temperatures. The output power fluctuation tested at 750°C was 1.06% over a period of 7 hours. The thermal regeneration grating fabrication process opens new possibilities to design and to implement fiber laser sensors for extreme environments. PMID:23939090

  7. Study of laser-induced damage to large core silica fiber by Nd:YAG and Alexandrite lasers

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoguang; Li, Jie; Hokansson, Adam; Whelan, Dan; Clancy, Michael

    2009-02-01

    As a continuation of our earlier study at 2.1 μm wavelength, we have investigated the laser damage to several types of step-index, large core (1500 μm) silica fibers at two new wavelengths by high power long pulsed Nd:YAG (1064 nm) and Alexandrite (755 nm) lasers. It was observed that fibers with different designs showed a significant difference in performance at these wavelengths. We will also report a correlation of damage to the fibers between the two laser wavelengths. The performance analyses of different fiber types under the given test conditions will enable optimization of fiber design for specific applications.

  8. Hydroxylapatite nanoparticles obtained by fiber laser-induced fracture

    NASA Astrophysics Data System (ADS)

    Boutinguiza, M.; Lusquiños, F.; Riveiro, A.; Comesaña, R.; Pou, J.

    2009-03-01

    This work presents the results of laser-induced fragmentation of hydroxylapatite microparticles in water dissolution. Calcined fish bones in form of powder, which were previously milled to achieve microsized particles, were used as precursor material. Two different laser sources were employed to reduce the size of the suspended particles: a pulsed Nd:YAG laser and a Ytterbium doped fiber laser working in continuous wave mode. The morphology as well as the composition of the obtained particles was characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and conventional and high resolution transmission electron microscopy (TEM, HRTEM). The results show that nanometric particles of hydroxylapatite and β-tricalcium phosphate as small as 10 nm diameter can be obtained.

  9. Fiber laser welding of nickel based superalloy Inconel 625

    NASA Astrophysics Data System (ADS)

    Janicki, Damian M.

    2013-01-01

    The paper describes the application of single mode high power fiber laser (HPFL) for the welding of nickel based superalloy Inconel 625. Butt joints of Inconel 625 sheets 0,8 mm thick were laser welded without an additional material. The influence of laser welding parameters on weld quality and mechanical properties of test joints was studied. The quality and mechanical properties of the joints were determined by means of tensile and bending tests, and micro hardness tests, and also metallographic examinations. The results showed that a proper selection of laser welding parameters provides non-porous, fully-penetrated welds with the aspect ratio up to 2.0. The minimum heat input required to achieve full penetration butt welded joints with no defect was found to be 6 J/mm. The yield strength and ultimate tensile strength of the joints are essentially equivalent to that for the base material.

  10. Fiber-optic laser sensor for mine detection and verification

    NASA Astrophysics Data System (ADS)

    Bohling, Christian; Scheel, Dirk; Hohmann, Konrad; Schade, Wolfgang; Reuter, Matthias; Holl, Gerhard

    2006-06-01

    What we believe to be a new optical approach for the identification of mines and explosives by analyzing the surface materials and not only bulk is developed. A conventional manually operated mine prodder is upgraded by laser-induced breakdown spectroscopy (LIBS). In situ and real-time information of materials that are in front of the prodder are obtained during the demining process in order to optimize the security aspects and the speed of demining. A Cr4+:Nd3+:YAG microchip laser is used as a seed laser for an ytterbium-fiber amplifier to generate high-power laser pulses at 1064 nm with pulse powers up to Ep=1 mJ, a repetition rate of frep.=2-20 kHz and a pulse duration of tp=620 ps. The recorded LIBS signals are analyzed by applying neural networks for the data analysis.

  11. Fiber-optic laser sensor for mine detection and verification.

    PubMed

    Bohling, Christian; Scheel, Dirk; Hohmann, Konrad; Schade, Wolfgang; Reuter, Matthias; Holl, Gerhard

    2006-06-01

    What we believe to be a new optical approach for the identification of mines and explosives by analyzing the surface materials and not only bulk is developed. A conventional manually operated mine prodder is upgraded by laser-induced breakdown spectroscopy (LIBS). In situ and real-time information of materials that are in front of the prodder are obtained during the demining process in order to optimize the security aspects and the speed of demining. A Cr4+:Nd3+:YAG microchip laser is used as a seed laser for an ytterbium-fiber amplifier to generate high-power laser pulses at 1064 nm with pulse powers up to E(p) = 1 mJ, a repetition rate of f(rep.) = 2-20 kHz and a pulse duration of t(p) = 620 ps. The recorded LIBS signals are analyzed by applying neural networks for the data analysis. PMID:16724144

  12. TECHNICAL NOTE: Development of fiber Bragg grating sensor system using wavelength-swept fiber laser

    NASA Astrophysics Data System (ADS)

    Ryu, Chi-Young; Hong, Chang-Sun

    2002-06-01

    Fiber Bragg grating (FBG) sensors based on the wavelength division multiplexing technology are ideally suited for structural health monitoring. In many applications, it is desirable to form several arrays of optical fiber sensors to monitor the response of structures. In the present study, we constructed an improved FBG sensor system using a wavelength-swept fiber laser which exhibits high output power for several sensor arrays. A fiber cavity etalon was also fabricated for the calibration of the nonlinear output wavelength of a laser and for scaling the information in the wavelength domain for signal processing. The constructed FBG sensor system with the fiber cavity etalon and a reference FBG was applied for strain measurements of a laminated composite panel under axial compressive loading. In order to monitor the structural strain in real time, the signal-processing program was constructed using LabVIEW software for storing and visualizing data from the FBG sensors. Experiments showed that the constructed FBG sensor system and the real-time signal-processing program could successfully monitor the strain of composite laminates. This improved FBG sensor system could be useful for large structures which require a large number of sensor arrays.

  13. Dynamic fiber Bragg grating strain sensor using a wavelength-locked tunable fiber ring laser

    NASA Astrophysics Data System (ADS)

    Zhu, Yinian; Krishnaswamy, Sridhar

    2012-04-01

    The interrogation systems based on fiber-optic sensors are very attractive for the practical applications in structural health monitoring owing to a number of advantages of optical fiber elements over their electronic counterparts. Among the fiber-optic sensors, the fiber Bragg gratings (FBGs) have their own unique features to be widely used for detection of acoustic emission. We have developed a dynamic strain sensing system by using a tunable single longitudinal mode Erbium-doped fiber ring laser to be locked to the middle-reflection wavelength of the FBG as the demodulation technique. A proportional-integral-derivative device continuously controls the laser wavelength that is kept at the FBG middle-reflection wavelength, thus stabilizing the operating point against quasi-static perturbation, while the high frequency dynamic strain shifts the FBG reflection profile. The reflected power varies in proportion to the applied strain which can be derived directly from AC photocurrent of the reflected signal. We have designed and assembled a fourchannel demodulator system for simultaneous high frequency dynamic strain sensing.

  14. Laparoscopic Partial Nephrectomy Using a Flexible CO2 Laser Fiber

    PubMed Central

    Khalaileh, Abed; Ponomarenko, Oleg; Abu-Gazala, Mahmoud; Lewinsky, Reuven M.; Elazary, Ram; Shussman, Noam; Shalhav, Arieh; Mintz, Yoav

    2012-01-01

    Background and Objectives: Laparoscopic partial nephrectomy (LPN) is a challenging surgery that requires precise tissue cutting and meticulous hemostasis under warm ischemia conditions. In this study, we tested the feasibility of performing LPN using CO2 laser energy transmitted through a specialized flexible mirror optical fiber. Methods: General anesthesia and pneumoperitoneum were induced in 7 farm pigs. Various portions of a kidney, either a pole or a midportion of the kidney, were removed using a novel flexible fiber to transmit CO2 laser energy set at a power of 45W and energy per pulse of 100mJ. The collecting system was approximated with a suture or 2, but no hemostatic measures were taken besides applying a few pulses of the laser to bleeding points. The pigs were sacrificed 3 wk later. Results: Average renal mass removed was 18% of the total kidney weight. All pigs tolerated surgery well. Sharp renal cutting was accomplished in a single continuous incision, with minimal tissue charring and minimal blood loss (<10cc) in all animals. Necropsy revealed no peritoneal or retroperitoneal abnormalities. Histologic examination of the cut surface showed a thin sector of up to 100 μm of coagulation necrosis. Conclusions: We report on the first LPN done using a CO2 laser transmitted through a flexible fiber in an animal model. This novel application of the CO2 laser produced excellent parenchymal incision and hemostasis along with minimal damage to adjacent renal tissue, thus, potentially shortening ischemia time and kidney function loss. Further studies comparing this laser to standard technique are necessary to verify its usefulness for partial nephrectomy. PMID:23484569

  15. Study of mid IR fiber transmission and mode patterns under laser induced stimulated Brillouin scattering

    NASA Technical Reports Server (NTRS)

    Yu, C.; Chong, Yat C.; Zhou, Hongyi

    1990-01-01

    Mid IR fiber transmission and exit radiation mode patterns at various incident CO2 laser power levels appear to be effective diagnostic tools for monitoring laser induced stimulated Brillouin scattering in various mid IR fibers. Such processes are deemed to be essential mechanisms for fiber-optic amplifiers and switches as potential replacements of current repeaters and bistable devices.

  16. A mode-locked fiber laser with a chirped grating mirror

    NASA Astrophysics Data System (ADS)

    Haus, J. W.; Hayduk, M.; Kaechele, W.; Shaulov, G.; Theimer, J.; Teegarden, K.; Wicks, G.

    2000-01-01

    A novel fiber laser was built using a multiple-quantum well mode-locking element and a chirped fiber grating to balance dispersion and nonlinearity. Energetic pulses as short as 2 ps were generated in the cavity and propagated in a fiber to determine the pulse characteristics. Laser cavity modeling and pulse propagation simulations are in good agreement with experiments.

  17. Switchable dual-wavelength fiber laser based on PCF Sagnac loop and broadband FBG

    NASA Astrophysics Data System (ADS)

    Chen, Weiguo; Lou, Shuqin; Feng, Suchun; Wang, Liwen; Li, Honglei; Guo, Tieying; Jian, Shuisheng

    2009-11-01

    Switchable dual-wavelength fiber laser with photonic crystal fiber (PCF) Sagnac loop and broadband fiber Bragg grating (BFBG) at room temperature is demonstrated. By adjusting the polarization controller (PC) appropriately, the laser can be switched between the stable single- and dual-wavelength lasing operations by exploiting polarization hole burning (PHB) and spectral hole burning effects (SHB).

  18. Photonic crystal fiber for fundamental mode operation of multicore fiber lasers and amplifiers

    NASA Astrophysics Data System (ADS)

    Wang, Chun-can; Zhang, Fan; Geng, Rui; Liu, Chu; Ning, Ti-gang; Tong, Zhi; Jian, Shui-sheng

    2008-11-01

    A mode-selection method based on a single-mode photonic crystal fiber (PCF) in the multicore fiber (MCF) lasers is presented. The designed PCF has a central core region formed by a missing air-hole, and three air-hole rings. With an appropriate choice of the design parameters of the PCF, the power coupling between the fundamental mode (FM) of the PCF and the fundamental MCF mode can be much higher than those between the FM and the other supermodes. As a result, the fundamental MCF mode has the maximum power reflection coefficient on the right-hand side of the MCF laser cavity, and dominates the output laser power. Since the maximum power of the fundamental MCF mode will lead to the desired laser beam profile, higher the fraction of the fundamental MCF mode power contained in the total output power contributes to higher beam quality. The numerical simulations show that the effectiveness of the fundamental MCF mode-selection is higher in the MCF lasers with the PCF as a mode-selection component than in the MCF lasers based on the free-space Talbot cavity method. Additionally, for the MCF amplifiers, an approach is presented to decrease the sensitivity of the amplifier performance to the variation of Gaussian beam waist utilizing the coupling between the Gaussian beam and the FM of the PCF. The numerical results show that this method can effectively increase the design flexibility for a broad range of the Gaussian beam waist.

  19. All-fiber widely tunable thulium laser

    NASA Astrophysics Data System (ADS)

    Stevens, G.; Legg, T.

    2016-03-01

    We present results from an all-fibre thulium laser system that can be tuned to any wavelength between 1710 - 2110 nm, without using any moving mechanical parts. An Acousto-Optic Tunable Filter (AOTF) is used as the tuning element, which allows for the wavelength to be tuned in ~ 20 μs. Core-pumped and cladding pumped thulium fibres are used to enable lasing action across the wavelength range. We use in-house fabricated fused fibre couplers and combiners that have a flattened coupling response with wavelength to allow for the system to be built in an all fibre design. These couplers have a coupling response that only varies by +/- 10% over the 400 nm operating range. The laser can output powers between 1-5 mW over 1710 - 2110 nm and has a linewidth of <0.2 nm. An Acousto-optic modulator is used as a switch on the output of the laser to switch the signal between core-pumped and cladding-pumped amplifier stages. This allows for the output signals to be amplified to ~1W levels.

  20. Successive soliton explosions in an ultrafast fiber laser.

    PubMed

    Liu, Meng; Luo, Ai-Ping; Yan, Yu-Rong; Hu, Song; Liu, Yi-Chen; Cui, Hu; Luo, Zhi-Chao; Xu, Wen-Cheng

    2016-03-15

    Soliton explosions, as one of the most fascinating nonlinear phenomena in dissipative systems, have been investigated in different branches of physics, including the ultrafast laser community. Herein, we reported on the soliton dynamics of an ultrafast fiber laser from steady state to soliton explosions, and to huge explosions by simply adjusting the pump power level. In particular, the huge soliton explosions show that the exploding behavior could operate in a sustained, but periodic, mode from one explosion to another, which we term as "successive soliton explosions." The experimental results will prove to be fruitful to the various communities interested in soliton explosions. PMID:26977664

  1. Delivery of Erbium:YAG laser radiation through side-firing germanium oxide optical fibers

    NASA Astrophysics Data System (ADS)

    Ngo, Anthony K.; Fried, Nathaniel M.

    2006-02-01

    The Erbium:YAG laser is currently being tested experimentally for endoscopic applications in urology, including more efficient laser lithotripsy and more precise incision of urethral strictures than the Holmium:YAG laser. While side-firing silica fibers are available for use with the Ho:YAG laser in urology, no such fibers exist for use with the Er:YAG laser. These applications may benefit from the availability of a side-firing, mid-infrared optical fiber capable of delivering the laser radiation at a 90-degree angle to the tissue. The objective of this study is to describe the simple construction and characterization of a side-firing germanium oxide fiber for potential use in endoscopic laser surgery. Side-firing fibers were constructed from 450-micron-core germanium oxide fibers of 1.45-m-length by polishing the distal tip at a 45-degree angle and placing a 1-cm-long protective quartz cap over the fiber tip. Er:YAG laser radiation with a wavelength of 2.94 microns, pulse duration of 300 microseconds, pulse repetition rate of 3 Hz, and pulse energies of from 5 to 550 mJ was coupled into the fibers. The fiber transmission rate and damage threshold measured 48 +/- 4 % and 149 +/- 37 mJ, respectively (n = 6 fibers). By comparison, fiber transmission through normal germanium oxide trunk fibers measured 66 +/- 3 %, with no observed damage (n = 5 fibers). Sufficient pulse energies were transmitted through the side-firing fibers for contact tissue ablation. Although these initial tests are promising, further studies will need to be conducted, focusing on assembly of more flexible, smaller diameter fibers, fiber bending transmission tests, long-term fiber reliability tests, and improvement of the fiber output spatial beam profile.

  2. Thulium fiber laser ablation of kidney stones using a 50-μm-core silica optical fiber

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard L.; Hutchens, Thomas C.; Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

    2015-01-01

    Our laboratory is currently studying the experimental thulium fiber laser (TFL) as a potential alternative laser lithotripter to the gold standard, clinical Holmium:YAG laser. We have previously demonstrated the efficient coupling of TFL energy into fibers as small as 100-μm-core-diameter without damage to the proximal end. Although smaller fibers have a greater tendency to degrade at the distal tip during lithotripsy, fiber diameters (≤200 μm) have been shown to increase the saline irrigation rates through the working channel of a flexible ureteroscope, to maximize the ureteroscope deflection, and to reduce the stone retropulsion during laser lithotripsy. In this study, a 50-μm-core-diameter, 85-μm-outer-diameter, low-OH silica fiber is characterized for TFL ablation of human calcium oxalate monohydrate urinary stones, ex vivo. The 50-μm-core fiber consumes approximately 30 times less cross-sectional area inside the single working channel of a ureteroscope than the standard 270-μm-core fiber currently used in the clinic. The ureteroscope working channel flow rate, including the 50-μm fiber, decreased by only 10% with no impairment of ureteroscope deflection. The fiber delivered up to 15.4±5.9 W under extreme bending (5-mm-radius) conditions. The stone ablation rate measured 70±22 μg/s for 35-mJ-pulse-energy, 500-μs-pulse-duration, and 50-Hz-pulse-rate. Stone retropulsion and fiber burnback averaged 201±336 and 3000±2600 μm, respectively, after 2 min. With further development, thulium fiber laser lithotripsy using ultra-small, 50-μm-core fibers may introduce new integration and miniaturization possibilities and potentially provide an alternative to conventional Holmium:YAG laser lithotripsy using larger fibers.

  3. Stable multiwavelength single longitudinal mode dual ring Brillouin fiber laser

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Yu, Jin-Long; Wang, Wen-Rui; Pan, Hong-Gang; Yang, En-Ze

    2015-04-01

    A novel stable multiwavelength single longitudinal mode (SLM) dual ring Brillouin fiber laser is proposed and demonstrated. Dual ring configuration with 100 and 10 m length of single mode fiber guarantees each Stokes and anti-Stokes waves in SLM status. Linewidth of the first Stokes wave is below 4 kHz with 60 dB sidemode suppression value. 7 stable SLM lasing wavelengths including the pump with a 5 dB bandwidth of 0.5, 0.084 nm wavelength spacing and 15 dB average optical signal-to-noise ratio are generated through the cascaded SBS and degenerate FWM process. The laser can freely be tuned 30 nm range from 1535 to 1565 nm. The power fluctuation of the first Stokes wave is about 8 % measured by Data Acquisition System in 1 h.

  4. Multi-meter fiber-delivery and pulse self-compression of milli-Joule femtosecond laser and fiber-aided laser-micromachining.

    PubMed

    Debord, B; Alharbi, M; Vincetti, L; Husakou, A; Fourcade-Dutin, C; Hoenninger, C; Mottay, E; Gérôme, F; Benabid, F

    2014-05-01

    We report on damage-free fiber-guidance of milli-Joule energy-level and 600-femtosecond laser pulses into hypocycloid core-contour Kagome hollow-core photonic crystal fibers. Up to 10 meter-long fibers were used to successfully deliver Yb-laser pulses in robustly single-mode fashion. Different pulse propagation regimes were demonstrated by simply changing the fiber dispersion and gas. Self-compression to ~50 fs, and intensity-level nearing petawatt/cm(2) were achieved. Finally, free focusing-optics laser-micromachining was also demonstrated on different materials. PMID:24921775

  5. Generation of 8 nJ pulses from a normal-dispersion thulium fiber laser.

    PubMed

    Tang, Yuxing; Chong, Andy; Wise, Frank W

    2015-05-15

    We report a study of a mode-locked thulium (Tm) fiber laser with varying normal dispersion. It is difficult to reach the high-energy dissipative-soliton regime due to the anomalous dispersion of most fibers at 2 μm. With large normal dispersion, the laser exhibits elements of self-similar pulse evolution, and is the first Tm fiber laser to achieve the performance benefits of normal-dispersion operation. The laser generates 7.6 nJ pulses, which can be dechirped to 130 fs duration. The resulting peak power is 4 times higher than that of previous Tm fiber lasers. PMID:26393739

  6. Laser Beam Delivery and Image Transmission Through Multimode Optical Fibers

    NASA Astrophysics Data System (ADS)

    Pan, Anpei

    This dissertation is dedicated to two important branches of optical fiber applications in biomedical engineering: laser beam delivery and image transmission. The optical phase of a light wave is distorted when it propagates through a multimode fiber. To compensate the distortion, a new hologram-generated phase conjugation theoretical model and experimental method has been developed. In the process, a self-pumped phase-conjugating mirror is introduced for recording the hologram. The coherence conditions are carefully matched so that only the desired optical signal is recorded. As a result, a high fidelity phase conjugation wave is produced. The resolution is 4.4 mum, which corresponds the diffraction-limited value of the system. Multimode optical fibers are widely used to deliver laser beams for medical diagnoses and treatments. However the spatial quality of the output beam is very poor. By use of holographic phase precompensation we present a new method to deliver high-quality laser beams. As a result, a highly collimated output beam with only 1.9 mrad divergence, which is 250 times smaller than the usual divergence, is obtained. The brightness is greatly increased. Other desired waves such as spherical wave or Gaussian beams can also be obtained. Another method, which is based on the formation at the remote end of a holographic filter, is also presented. The final output beams are nearly diffraction -limited. The hologram-generated phase conjugation is applied to image transmission through single multimode fibers. By use of Fourier transform theory and the formalism established in this study, the system resolution and the space bandwidth product are analyzed. The resolution of a multimode fiber can be 50 times higher than that of an imaging bundle if their diameters are the same. In the experiments a resolution chart was tested. The experimental results are quite consistent with the theory. A 3-D biological sample--a tooth--was also tested. The limitations of the

  7. Polarization maintaining linear cavity Er-doped fiber femtosecond laser

    NASA Astrophysics Data System (ADS)

    Jang, Heesuk; Jang, Yoon-Soo; Kim, Seungman; Lee, Keunwoo; Han, Seongheum; Kim, Young-Jin; Kim, Seung-Woo

    2015-10-01

    We present a polarization-maintaining (PM) type of Er-doped fiber linear oscillator designed to produce femtosecond laser pulses with high operational stability. Mode locking is activated using a semiconductor saturable absorber mirror (SESAM) attached to one end of the linear PM oscillator. To avoid heat damage, the SESAM is mounted on a copper-silicon-layered heat sink and connected to the linear oscillator through a fiber buffer dissipating the residual pump power. A long-term stability test is performed to prove that the proposed oscillator design maintains a soliton-mode single-pulse operation without breakdown of mode locking over a week period. With addition of an Er-doped fiber amplifier, the output power is raised to 180 mW with 60 fs pulse duration, from which an octave-spanning supercontinuum is produced.

  8. Flexible hollow polycarbonate fiber for endoscopic infrared laser treatment

    NASA Astrophysics Data System (ADS)

    Nakazawa, Masayuki; Shi, Yi-Wei; Iwai, Katsumasa; Matsuura, Yuji; Zhu, Xiao-Song; Miyagi, Mitsunobu

    2007-07-01

    For endoscopic application, inexpensive, safe, and extremely flexible hollow infrared optical fibers have been fabricated based on the polycarbonate (PC) capillary with silver and cyclic olefin polymer (COP) as inner coatings. By optimizing the drawing condition of PC capillary from a commercially available polycarbonate tube and inner-coating process, transmission efficiency of hollow PC fibers is shown to be equal to those of glass capillary based ones. Both Er:YAG laser light and green pilot beam were delivered through the endoscope with low losses even when it was sharply bent with a bending radius as small as 1 centimeter. Preliminary experiments were also conducted on possibility of transmitting infrared thermal image by using bundled silver-coated PC hollow fibers.

  9. Fiber laser FBG sensor system by using a spectrometer demodulation

    NASA Astrophysics Data System (ADS)

    Kim, Hyunjin; Song, Minho

    2011-05-01

    We suggest a spectrometer demodulation method of FBG sensors for the possible uses in wind power generator's blade monitoring. High signal-to-noise ratio outputs and linear demodulation were obtained by combining a fiber laser light source and a spectrometer which used a holographic volume grating and a 512-pixel PD array. Preliminary experimental results are presented to show the feasibility of the suggested FBG demodulation system.

  10. Subpicosecond solitons in an actively mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Jones, D. J.; Haus, H. A.; Ippen, E. P.

    1996-11-01

    Experimental results are presented for a study of the stability regime of an actively mode-locked polarization-maintaining fiber ring laser used as a memory. Observations indicate that the pulse widths in the memory can be reduced (by soliton effects) by a factor of approximately 4.4 below the pulse widths predicted by standard active mode-locking theory. Stability regions for the solitons are mapped and compared with theoretical predictions.

  11. Fiber optic detector probes for laser light scattering

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans S.; Wu, Chi; Chu, Benjamin

    1989-01-01

    An experimental investigation of the role of fiber optic detector probes in laser light scattering is presented. A quantitative comparison between different detector configurations is accomplished by measuring the time taken for one million photocounts to be accumulated in the extrapolated zeroth delay channel of the net unnormalized intensity time correlation function. A considerable reduction in the accumulation time is achieved by relaxing a rather stringent requirement for the spatial coherence of the optical field.

  12. Fiber laser hydrophone as possible detector of UHE neutrinos

    NASA Astrophysics Data System (ADS)

    Maccioni, E.; Bagnoli, P. E.; Beverini, N.; Bouhadef, B.; Castorina, E.; Falchini, E.; Falciai, R.; Flaminio, V.; Morganti, M.; Stefani, F.; Trono, C.

    2007-03-01

    The possibility to use a single mode erbium-doped fiber laser as hydrophone for deep sea acoustic detection is considered. The high sensitivity of these sensors, their immunity from electromagnetic fields and their faculty to work at high environmental pressure, make them particularly suitable for a wide range of deep sea acoustic applications, and in particular as acoustic detectors in under-water telescopes for high-energy neutrinos.

  13. Erbium-doped fiber lasers as deep-sea hydrophones

    NASA Astrophysics Data System (ADS)

    Bagnoli, P. E.; Beverini, N.; Bouhadef, B.; Castorina, E.; Falchini, E.; Falciai, R.; Flaminio, V.; Maccioni, E.; Morganti, M.; Sorrentino, F.; Stefani, F.; Trono, C.

    2006-11-01

    The present work describes the development of a hydrophone prototype for deep-sea acoustic detection. The base-sensitive element is a single-mode erbium-doped fiber laser. The high sensitivity of these sensors makes them particularly suitable for a wide range of deep-sea acoustic applications, including geological and marine mammals surveys and above all as acoustic detectors in under-water telescopes for high-energy neutrinos.

  14. Detection of rail corrugation based on fiber laser accelerometers

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  15. Flexible high-repetition-rate ultrafast fiber laser

    PubMed Central

    Mao, Dong; Liu, Xueming; Sun, Zhipei; Lu, Hua; Han, Dongdong; Wang, Guoxi; Wang, Fengqiu

    2013-01-01

    High-repetition-rate pulses have widespread applications in the fields of fiber communications, frequency comb, and optical sensing. Here, we have demonstrated high-repetition-rate ultrashort pulses in an all-fiber laser by exploiting an intracavity Mach-Zehnder interferometer (MZI) as a comb filter. The repetition rate of the laser can be tuned flexibly from about 7 to 1100 GHz by controlling the optical path difference between the two arms of the MZI. The pulse duration can be reduced continuously from about 10.1 to 0.55 ps with the spectral width tunable from about 0.35 to 5.7 nm by manipulating the intracavity polarization controller. Numerical simulations well confirm the experimental observations and show that filter-driven four-wave mixing effect, induced by the MZI, is the main mechanism that governs the formation of the high-repetition-rate pulses. This all-fiber-based laser is a simple and low-cost source for various applications where high-repetition-rate pulses are necessary. PMID:24226153

  16. Frequency doubling of fiber laser radiation of large spectral bandwidths

    NASA Astrophysics Data System (ADS)

    Nyga, Sebastian; Geiger, Jens; Jungbluth, Bernd

    2010-02-01

    In this work the reduction of conversion efficiency due to spectral bandwidth of fiber laser radiation is investigated. Subsequently, compensation optics to correct the spectral phase mismatching inside the nonlinear crystal is dimensioned and tested. For the experimental study a laboratory fiber laser setup is used consisting of a seed diode and a three stage fiber amplifier. The laser delivers an average output power of up to 100 W at 1 MHz. Even below the Raman threshold the output is far away from Fourier limit, providing a nearly Lorentzian spectral shape and a temporal pulse width of 800 ps. As the bandwidth increases nearly linearly with the pump power of the third amplifier stage, this parameter could be controlled for the experiments. All conversion experiments are conducted with a moderate load of the nonlinear crystals, i.e. intensity less than 150 MW/cm2. Without compensation of the spectral phase mismatch, a maximum conversion efficiency of 15 % is attained for a Type I configuration with a 20mm long LBO crystal. Using the compensation setup 27 W of green light are obtained from 60 W infrared light at a bandwidth of 4.7 nm. Therefore the efficiency rises to 44% at the same load.

  17. Fiber photo-catheters for laser treatment of atrial fibrillation

    NASA Astrophysics Data System (ADS)

    Peshko, Igor; Rubtsov, Vladimir; Vesselov, Leonid; Sigal, Gennady; Laks, Hillel

    2007-04-01

    A fiber photo-catheter has been developed for surgical treatment of atrial fibrillation with laser radiation. Atrial fibrillation (AF) is a heart rhythm abnormality, which involves irregular and rapid heartbeats. Recent studies demonstrate the superiority of treating AF disease with optical radiation of the near-infrared region. To produce long continuous transmural lesions, solid-state lasers and laser diodes, along with end-emitting fiber catheters, have been used experimentally. The absence of side-emitting flexible catheters with the ability to produce long continuous lesions limits the further development of this technology. In this research, a prototype of an optical catheter, consisting of a flexible 10-cm fiber diffuser has been used to make continuous photocoagulation lesions for effective maze procedure treatments. The system also includes a flexible optical reflector, a series of openings for rapid self-attachment to the tissue, and an optional closed-loop irrigating chamber with circulating saline to cool the optical diffuser and irrigate the tissue.

  18. LD-cladding-pumped 50 pm linewidth Tm 3+ -doped silica fiber laser.

    PubMed

    Yunjun, Zhang; Baoquan, Yao; Youlun, Ju; Hui, Zhou; Yuezhu, Wang

    2008-05-26

    We report on a Tm(3+)-doped fiber laser source operating at 1936.4 nm with a very narrow linewidth (50 pm) laser output. Up to 2.4 W cw laser power was obtained from an 82 cm long Tm(3+)-doped multimode-core fiber cladding pumped by a 792 nm laser diode (LD). The fiber laser cavity included a high-reflective dichroic and a low-reflective FBG output coupler. The multimode fiber Bragg grating (FBG) transmission spectrum and output laser spectrum were measured. By adjusting the distance between the dichroic and the Tm(3+)-doped fiber end, the multipeak laser spectrum changed to a single-peak laser spectrum. PMID:18545481

  19. 1 mJ nanosecond all-fiber thulium-doped fiber laser at 2.05 μm.

    PubMed

    Li, Lei; Zhang, Bin; Yin, Ke; Yang, Linyong; Hou, Jing

    2015-07-13

    A high energy all-fiber format nanosecond thulium-doped fiber laser at 2050 nm with a master oscillator power amplifier (MOPA) configuration is presented in this paper. The seed oscillator is a linearly polarized gain-switched fiber laser pumped by a 1550 nm fiber laser. The output pulse of the seed has a polarization extinction ratio (PER) better than 16 dB with a maximal output power of 470 mW. After two-stage double- cladding fiber amplifiers, the average power at 40 kHz was boosted up to 40.5 W. The output pulse has a maximum pulse energy of 1 mJ with a pulse width of 100 ns, which corresponds to a peak power of 10 kW. To the best of our knowledge, it is the highest single pulse energy ever reported for a nanosecond thulium-doped all-fiber MOPA system at 2050 nm. PMID:26191869

  20. Multi-beam Laser Doppler Vibrometer with fiber sensing head

    NASA Astrophysics Data System (ADS)

    Phua, P. B.; Fu, Y.; Guo, M.; Liu, H.

    2012-06-01

    Laser Doppler vibrometry (LDV) is a well known technique to measure the motions, vibrations and mode shapes of structures and machine components. Photodetector-based LDV can only offer a point-wise measurement. However, it is possible to scan the laser beam to build up a vibrometric image. These scanning laser Doppler vibrometers (SLDV) assume that the measurement conditions remain invariant while multiple and identical, sequential measurements are performed. This assumption makes SLDVs impractical to do measurement on transient events. In this paper, we introduce a new method of generating multiple laser beams with different frequency shifts. The laser beams are projected on different points, and the reflected beams interfere with a common reference beam. The cross-talk among object beams can be bypassed with a proper selection of frequency shifts. A simultaneous vibration measurement on multiple points is realized using a single photodetector. Based on the proposed spatial-encoding technology, a self-synchronized prototype of fiber-based multipoint laser Doppler vibrometer at 1550nm wavelength is developed. An addition red pilot laser is used for aiming purpose. It has the flexibility to measure the vibration of different points on various surfaces. The prototype is used to measure the vibration of different points on a cantilever beam and a plate. The measured results match well with simulation results using finite element method (FEM).

  1. Wavelength tunability of L-band fiber ring lasers using mechanically induced long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Sakata, Hajime; Yoshimi, Hitoshi; Otake, Yuki

    2009-03-01

    We report on oscillation wavelength control in erbium-doped fiber ring lasers by adjusting the period of a mechanically induced long-period fiber grating (LPFG) inserted into the fiber ring resonator. Pump light is provided by a 974 nm laser diode (LD), the emission of which is coupled into the fiber ring resonator through a wavelength-division multiplexing coupler. Laser oscillation occurs with a threshold pump LD current of 40 mA, corresponding to a threshold pump power of 5 mW. When a periodic pressure of 0.81 N/mm is applied to form the LPFG, the fiber ring laser exhibits the tunable range of 40.9 nm, i.e., from 1563.1 to 1604 nm, by changing the grating period.

  2. An optimized fiber delivery system for Q-switched, Nd:YAG lasers

    SciTech Connect

    Setchell, R.E.

    1996-11-01

    Interest in the transmission of high intensities through optical fibers is being motivated by an increasing number of applications. Using different laser types and fiber materials, various studies are encountering transmission limitations due to laser-induced damage processes. The authors have found that fiber transmission is often limited by a plasma-forming breakdown occurring at the fiber entrance face. System attributes that will affect breakdown and damage thresholds include laser characteristics, the design and alignment of laser-to-fiber injection optics, and fiber end-face preparation. In the present work the authors have combined insights gained in past studies in order to establish what thresholds can be achieved if all system attributes can be optimized to some degree. The multimode laser utilized past modifications that produced a relatively smooth, quasi-Gaussian profile. The laser-to-fiber injection system achieved a relatively low value for the ratio of peak-to-average fluences at the fiber entrance face, incorporated a mode scrambler to generate a broad mode power distribution within the initial segment of the fiber path, and had improved fixturing to insure that the fiber axis was collinear with the incident laser beam. Fiber end faces were prepared by a careful mechanical polishing schedule followed by surface conditioning using a CO{sub 2} laser. In combination, these factors resulted in higher thresholds for breakdown and damage than they had achieved previously in studies that utilized a simple lens injection system.

  3. Investigation on the applications of fiber grating lasers in industrial sensing and pollution monitoring

    NASA Astrophysics Data System (ADS)

    Xu, Yuanzhong

    The main objective of the project was to develop ``eye-safe'' fiber-grating lasers for pollution measurement and monitoring. Fiber grating lasers have a number of advantages such as narrow linewidth and precise wavelength control over the semiconductor counterparts. Three types of Erbium doped fiber grating lasers emitting in 1.5 μm band were developed and characterized in this work. We first used an entirely original approach to develop tunable dual-wavelength switchable fiber grating laser for differential absorption spectroscopy. The lam can switch between two wavelengths with each wavelength being independently tunable. It's characterized by >6-mW output power, <2% intensity fluctuation, 100s Hz switching speed and 1:100,000 wavelength extinction ratio. The outstanding advantage of this approach is the simplicity in laser configuration as well as in detection system for dual wavelength laser, because it uses only an overlapped gain medium and one detector for both wavelengths. Main drawbacks of the prototype laser are slow switching speed (100s Hz) and multimode operation, which could be overcome by cavity dampening and modification in laser configuration. Short cavity erbium-doped fiber grating lasers using high Erbium concentration were also studied. A 6-cm long fiber-grating laser pumped by a 980-nm laser diode was constructed. The linewidth of the laser is very narrow (~100s kHz) but its output slope efficiency is relatively low (~1%). Furthermore, the ion clustering effect arising from high Er concentration tends to cause self-pulsation and thus instability to the laser. By replacing the Erbium doped fiber with Er/Yb codoped one, the fiber grating laser was made more stable and efficient. The ion clustering effect disappears in the laser output due to the low Erbium concentration in Er/Yb codoped fiber, while the Er/Yb codoped fiber's two orders higher pump absorption at 980 nm results in as large as 10 ~ 30% output slope efficiency in about 2 cm long

  4. Laser & Fiber Optics: Instructional Manual. The North Dakota High Technology Mobile Laboratory Project.

    ERIC Educational Resources Information Center

    Eickhoff, Luvern R.

    This instructional manual contains 20 learning activity packets for use in a workshop on lasers and fiber optics. The lessons cover the following topics: what a laser; coherent light; setting up the laser; characteristics of the laser beam; scattering of light; laser beam divergence, intensity, color, ophthalmology, and reflections; directivity of…

  5. Novel multiple output and multiwavelength fiber ring-optical laser

    NASA Astrophysics Data System (ADS)

    Tsao, Shyh-Lin; Lin, Huang-Cuang

    2003-12-01

    The fiber ring structures optical signal processor with semiconductor optical amplifiers (SOA's) have been developed [1]. The SOA's have been demonstrated the ability of direct signal processing combining the optical amplification with ether modulation, detection, or wavelength conversion [2,3]. Moreover, the fiber-optical processors have many advantages. In this paper, we purpose new design configurations of an 8x8 array waveguide grating (AWG) connected to an SOA to achieve a ring configuration and experimentally measure its characteristics. In this paper, we can get fourteen signal processing output simultaneously by using such a fiber ring construction. The multiwavelenght and multiple output rings signal processor can be implemented by connecting any pair of the 8x8 AWG to the SOA. This application can develop a multiple-input-multiple-output processing only optical amplifier. We will present various useful parameters of application this fiber optic processor. References [1] Goodman, J.W.; Moslehi, B, "Novel amplified fiber-optic recirculating delay line processor", J.Lightwave Technol., Vol. 10 Issue: 8, pp.1142-1147, 1992 [2] U. Koren, B. I. Miller, M. G. Yang, T. L. Koch, R. M. Jopson, A. Gnauck, D. Evankow, and M. Chien, "High frequency modulation of strained layer multiple quantum well optical amplifiers", Electron. Lett., vol. 27, pp.62-64, 1991. [3] M. Gustavsson, A. Karlsson, and L. Thylen, "Traveling wave semiconductor laser amplifiers detectors", J. Lightwave Technol., vol. 8, pp. 610-617, 1990.

  6. Coilable single crystal fibers of doped-YAG for high power laser applications

    NASA Astrophysics Data System (ADS)

    Maxwell, Gisele; Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet

    2013-05-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They can combine the advantages of both by guiding laser light and matching the efficiencies found in bulk crystals, making them ideal candidates for high-power laser and fiber laser applications. In particular, a very interesting feature of single crystal fiber is that they can generate high power in the eye-safe range (Er:YAG) with a high efficiency, opening new possibilities for portable directed energy weapons. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc…) that will exhibit good waveguiding properties. Direct growth or a combination of growth and cladding experiments are described. We have, to date, demonstrated the growth of a flexible foot long 45 microns doped YAG fiber. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  7. Stable double spacing multiwavelength Brillouin-Erbium doped fiber laser based on highly nonlinear fiber

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    A double frequency spaced multiwavelength Brillouin-Erbium doped fiber laser (BEDFL) with figure-of-eight cavity have been successfully developed and tested. Double frequency spacing is achieved by using a piece of 2 km of highly nonlinear fiber (HNLF) as a gain medium. Figure-of-eight configuration removes the odd order Stokes signals via a four-port circulator. Fifteen Stokes channels are simultaneously generated with a spacing of 0.154 nm that is around 20 GHz, when the Brillouin pump and 980 nm pump powers are fixed at the optimized values of 6 dBm and 40 mW, respectively. Fourteen anti stoke channels are also obtained, which are generated through four wave mixing (FWM) process in the laser cavity. The output is smooth triangular comb. The BEFL can also be tuned from 1526.5 to 1567.5 nm.

  8. Fiber laser sensor based on fiber-Bragg-grating Fabry-Perot cavity

    NASA Astrophysics Data System (ADS)

    Chen, Jianfeng; Liu, Yunqi; Cai, Tongjian; Wang, Tingyun

    2011-01-01

    We propose a fiber-Bragg-grating Fabry-Perot (FBG-FP) cavity sensor interrogated by a pulsed laser. The FBG-FP cavity is directly written into the same photosensitive fiber, which consists of a pair of FBGs with identical center wavelength. The modulated laser pulses are launched into the FBG-FP cavity. Each pulse produces a group of reflection and transmission pulses. The cavity loss in the FBG-FP cavity is determined from the power ratio of the first two pulses reflected from the cavity, which could be detected for the sensor measurement. This technique has the advantages that it does not require high reflectivity FBG and is immune to the power fluctuation of the light source.

  9. Fiber laser sensor based on fiber-Bragg-grating Fabry-Perot cavity

    NASA Astrophysics Data System (ADS)

    Chen, Jianfeng; Liu, Yunqi; Cai, Tongjian; Wang, Tingyun

    2010-12-01

    We propose a fiber-Bragg-grating Fabry-Perot (FBG-FP) cavity sensor interrogated by a pulsed laser. The FBG-FP cavity is directly written into the same photosensitive fiber, which consists of a pair of FBGs with identical center wavelength. The modulated laser pulses are launched into the FBG-FP cavity. Each pulse produces a group of reflection and transmission pulses. The cavity loss in the FBG-FP cavity is determined from the power ratio of the first two pulses reflected from the cavity, which could be detected for the sensor measurement. This technique has the advantages that it does not require high reflectivity FBG and is immune to the power fluctuation of the light source.

  10. Broadly tunable multiwavelength Brillouin-erbium fiber laser using a twin-core fiber coupler

    NASA Astrophysics Data System (ADS)

    Peng, Wanjing; Yan, Fengping; Li, Qi; Liu, Shuo; Tan, Siyu; Feng, Suchun; Feng, Ting

    2014-07-01

    A tunable multiwavelength Brillouin-erbium fiber laser (MW-BEFL) using a twin-core fiber (TCF) coupler is proposed and demonstrated. The TCF coupler is formed by splicing a section of TCF between two single-mode fibers. By simply applying bending curvature on the TCF coupler, the peak net gain is shifted close to the Brillouin pump (BP), which has advantage for suppressing self-lasing cavity modes with low-BP-power injection. In this work, the dependency of the Stokes signals tuning range on the free spectral range (FSR) of TCF coupler is studied. It is also found that the tuning range of MW-BEFL can exceed the FSR of TCF coupler by adopting proper BP power and 980-nm pump power. Up to 40 nm tuning range of MW-BEFL in the absence of self-lasing cavity modes is achieved.

  11. Galvanometer beam-scanning system for laser fiber drawing.

    PubMed

    Oehrle, R C

    1979-02-15

    A major difficulty in using a laser to draw optical fibers from a glass preform has been uniformally distributing the laser's energy around the melt zone. Several systems have evolved in recent years, but to date the most successful technique has been the off-axis rotating lens system (RLS). The inability of this device to structure efficiently and dynamically the heat zone longitudinally along the preform has restricted its use to preform of less than 8-mm diameter. A new technique reported here employs two orthogonal mounted mirrors, driven by galvanometers to distribute the laser energy around the preform. This system can be retrofitted into the RLS to replace the rotating lens element. The new system, the galvanometer scanning system (GSS), operates at ten times the rotational speed of the RLS and can instantaneously modify the melt zone. The ability of the GSS to enlarge the melt zone reduces the vaporization rate at the surface of the preform permitting efficient use of higher laser power. Experiments i dicate that fibers can be drawn from significantly larger preforms by using the expanded heat zone provided by the GSS. PMID:20208750

  12. All-fiber widely wavelength-tunable thulium-doped fiber ring laser incorporating a Fabry-Perot filter

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Hu, K.; Sun, B.; Wang, T.

    2012-04-01

    We demonstrate 1940 to 2010 nm continuous CW wavelength-tuning in a thulium-doped fiber laser (TDFL), using only fiber-format components. A fiber Fabry-Perot (FP) tunable filter is employed to achieve the wavelength tunability of 70 nm. By imposing a 200 Hz triangle wave signal on the filter, rapid wavelength-sweeping is demonstrated from 1952 to 1992 nm every 5 ms, corresponding to 8 nm/ms. This all-fiber wavelength-tunable and swept laser may find applications such as gas monitoring in the wavelength region of 2 μm.

  13. Compact non-cascaded all-fiber Raman laser operating at 1174 nm

    NASA Astrophysics Data System (ADS)

    Wang, Jiachen; Lee, Sang Bae; Lee, Kwanil

    2016-07-01

    We investigate a non-cascaded, all-fiber, single-mode Raman fiber laser (RFL) operating at 1174 nm with an optical slope efficiency of 68%. An ~1-km commercial single-mode fiber is used as the Raman gain medium. The RFL cavity is formed between a high reflectivity fiber Bragg grating (FBG) and a perpendicularly-cleaved fiber facet. The laser is pumped by using a homemade ytterbium-doped fiber laser (YDFL) and can be frequency doubled to generate yellow light. Under the optimum condition, A 6.9-W 1174-nm laser is obtained at maximum available power (24 W) of a laser diode pump. The optical conversion efficiency and the net slope efficiency of the RFL were respectively, 29% and 38%, with respect to launched diode laser power. We also demonstrate yellow-light generation by frequency doubling of the RFL.

  14. Intense short-pulse lasers irradiating wire and hollow plasma fibers.

    PubMed

    Zhou, C T; He, X T; Chew, L Y

    2011-03-15

    When an intense laser pulse irradiates a solid-density foil target, electrons produced at the relativistic critical density can be accelerated to relativistic energy by the ponderomotive force. When a plasma fiber is attached to the back of the foil, the produced relativistic electrons are guided to propagate along the fiber for a long distance, because the high-current electron beam induces strong radial electric fields in the fiber. Transport and heating of intense laser-driven relativistic electrons in both wire and hollow plasma fibers are compared theoretically and numerically. We found that the coupling efficiency from the laser to the plasma fiber depends on the fiber structure. Because of the enhanced return currents in the wire fiber, the temperature in the wire fiber is higher than that in the hollow fiber. PMID:21403730

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

    NASA Astrophysics Data System (ADS)

    Huang, Kaiqiang; Li, Qi; Chen, Haiyan

    2016-04-01

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

  16. Optical fiber configurations for transmission of laser energy over great distances

    SciTech Connect

    Rinzler, Charles C; Zediker, Mark S

    2013-10-29

    There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

  17. Tapered cladding diameter profile design for high-power tandem-pumped fiber lasers

    NASA Astrophysics Data System (ADS)

    Huang, Zhihua; Tang, Xuan; Lin, Honghuan; Wang, Jianjun

    2016-05-01

    The thermal effect has become the biggest limiting factor regarding the further power scaling of single mode fiber lasers, and it can lead to coating failure and transverse mode instability. A tapered cladding diameter profile design is proposed for the tandem-pumped fiber laser in this work, as it can smooth the temperature profile and reduce the maximum temperature rise within the fiber tremendously. The improvement in performance of the fiber design is verified by analytical and numerical results.

  18. Optical fiber configurations for transmission of laser energy over great distances

    SciTech Connect

    Rinzler, Charles C; Zediker, Mark S

    2014-11-04

    There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

  19. Stable dual-wavelength erbium fiber laser for temperature measurements

    NASA Astrophysics Data System (ADS)

    Diaz, S.; Lopez-Amo, M.

    2015-09-01

    In this work, a new stable dual-wavelength erbium fiber ring laser is proposed and experimentally demonstrated. This configuration is made by creating two symmetrical laser cavities with similar optical power. This topology allows the performance of two laser emission lines in single-longitudinal mode and with a power instability lower than 0.23 dB, and an optical signal-to-noise ratio higher than 40 dB for all the emitted wavelengths. The sensing capability of the FBGs enables this source to be also used as sensor-network multiplexing scheme. The system offers a better stability and higher optical signal to noise ratios than similar configurations.

  20. A robust all-fiber active Q-switched 1-µm Yb3+ fiber laser

    NASA Astrophysics Data System (ADS)

    Sintov, Yoav; Goldring, Sharone; Pearl, Shaul; Lebiush, Eyal; Sfez, Bruno; Malka, Dror; Zalevsky, Zeev

    2015-09-01

    An all-fiber active Q-switched Yb3+-doped fiber laser at 1 µm is presented. The laser is composed of a ring resonator with an embedded all-fiber Q-switch element, based on a null coupler with an attached piezoelectric transducer (PZT). The PZT is used as an acoustic actuator, for inducing longitudinal acoustic disturbance along the null coupler and causing light coupling between the null coupler's ports. A stable operation is achieved with an overall average output power of up to 275 mW at various pulse repetition rates (PRR), ranging from 10 to 35 kHz and typical pulse energy of 15 μJ. In addition, a self-monitoring method is implemented by an embedded microcontroller, in order to maintain stable Q-switch performance, in changing environmental conditions. An average power of 8.5 W and pulse energy of 420 μJ at a PRR of 20 kHz are demonstrated in a master oscillator power amplifier containing the Q-switched laser, followed by a power amplifier.

  1. Passively Q-switched Ho:YLF laser pumped by Tm3+-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Ju, Youlun; Yao, Baoquan; Dai, Tongyu; Duan, Xiaoming; Li, Jiang; Ding, Yu; Liu, Wei; Pan, Yubai; Li, Chaoyu

    2016-03-01

    We demonstrate a compact and efficient passively Q-switched (PQS) Ho:YLF laser pumped by a self-made all-fiber laser. Firstly, we design and make an all-fiber laser operating at 1940 nm with a slope efficiency of 40.6%. Then, the all-fiber laser was used to pump Ho:YLF laser directly. In the CW (continues-wave) operation Ho:YLF laser, the maximum output power was 7.79 W, corresponding to the slope efficiency of 55.2%. Using Cr2+:ZnS as the saturable absorber, the average power of 6.03 W was achieved with the slope efficiency of 45.9%. The shortest pulse duration was 15.6 ns and the pulse repetition frequency was 2.3 kHz at the pump power of 20.4 W. The pulse energy was a constant as 2.7 mJ when the pump power exceeded 15 W. The beam quality factor of M2 was 1.05, indicating nearly diffraction limited beam propagation.

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

    PubMed

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

    2015-07-27

    Few-layer black phosphorus (BP), as the most alluring graphene analogue owing to its similar structure as graphene and thickness dependent direct band-gap, has now triggered a new wave of research on two-dimensional (2D) materials based photonics and optoelectronics. However, a major obstacle of practical applications for few-layer BPs comes from their instabilities of laser-induced optical damage. Herein, we demonstrate that, few-layer BPs, which was fabricated through the liquid exfoliation approach, can be developed as a new and practical saturable absorber (SA) by depositing few-layer BPs with microfiber. The saturable absorption property of few-layer BPs had been verified through an open-aperture z-scan measurement at the telecommunication band. The microfiber-based BP device had been found to show a saturable average power of ~4.5 mW and a modulation depth of 10.9%, which is further confirmed through a balanced twin detection measurement. By integrating this optical SA device into an erbium-doped fiber laser, it was found that it can deliver the mode-locked pulse with duration down to 940 fs with central wavelength tunable from 1532 nm to 1570 nm. The prevention of BP from oxidation through the "lateral interaction scheme" owing to this microfiber-based few-layer BP SA device might partially mitigate the optical damage problem of BP. Our results not only demonstrate that black phosphorus might be another promising SA material for ultrafast photonics, but also provide a practical solution to solve the optical damage problem of black phosphorus by assembling with waveguide structures such as microfiber. PMID:26367661

  3. Welding of PMMA by a femtosecond fiber laser.

    PubMed

    Volpe, Annalisa; Di Niso, Francesca; Gaudiuso, Caterina; De Rosa, Andrea; Vázquez, Rebeca Martínez; Ancona, Antonio; Lugarà, Pietro Mario; Osellame, Roberto

    2015-02-23

    Developing versatile joining techniques to weld transparent materials on a micrometer scale is of great importance in a growing number of applications, especially for the fabrication and assembly of biomedical devices. In this paper, we report on fs-laser microwelding of two transparent layers of polymethyl methacrylate (PMMA) based on nonlinear absorption and localized heat accumulation at high repetition rates. A fiber CPA laser system was used delivering 650-fs pulses at 1030 nm with repetition rates in the MHz regime. The laser-induced modifications produced by the focused beam into the bulk PMMA were firstly investigated, trying to find a suitable set of process parameters generating continuous and localized melting. Results have been evaluated based on existing heat accumulation models. Then, we have successfully laser welded two 1-mm-thick PMMA layers in a lap-joint configuration. Sealing of the sample was demonstrated through static and dynamic leakage tests. This fs-laser micro-welding process does not need any pre-processing of the samples or any intermediate absorbing layer. Furthermore, it offers several advantages compared to other joining techniques, because it prevents contamination and thermal distortion of the samples, thus being extremely interesting for application in direct laser fabrication of microfluidic devices. PMID:25836449

  4. Wideband saturable absorption in few-layer molybdenum diselenide (MoSe₂) for Q-switching Yb-, Er- and Tm-doped fiber lasers.

    PubMed

    Woodward, R I; Howe, R C T; Runcorn, T H; Hu, G; Torrisi, F; Kelleher, E J R; Hasan, T

    2015-07-27

    We fabricate a free-standing molybdenum diselenide (MoSe2) saturable absorber by embedding liquid-phase exfoliated few-layer MoSe2 flakes into a polymer film. The MoSe2-polymer composite is used to Q-switch fiber lasers based on ytterbium (Yb), erbium (Er) and thulium (Tm) gain fiber, producing trains of microsecond-duration pulses with kilohertz repetition rates at 1060 nm, 1566 nm and 1924 nm, respectively. Such operating wavelengths correspond to sub-bandgap saturable absorption in MoSe2, which is explained in the context of edge-states, building upon studies of other semiconducting transition metal dichalcogenide (TMD)-based saturable absorbers. Our work adds few-layer MoSe2 to the growing catalog of TMDs with remarkable optical properties, which offer new opportunities for photonic devices. PMID:26367663

  5. Experimental Performance of a Single-Mode Ytterbium-doped Fiber Ring Laser with Intracavity Modulator

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Camp, Jordan

    2012-01-01

    We have developed a linearly polarized Ytterbium-doped fiber ring laser with a single longitudinal mode output at 1064 run. A fiber-coupled intracavity phase modulator ensured mode-hop free operation and allowed fast frequency tuning. The fiber laser was locked with high stability to an iodine-stabilized laser, showing a frequency noise suppression of a factor approx 10 (exp 5) at 1 mHz

  6. Multi-coupler side-pumped Yb-doped double-clad fiber laser

    NASA Astrophysics Data System (ADS)

    Ou, Pan; Yan, Ping; Gong, Mali; Wei, Wenlou

    2004-05-01

    The side-coupler of angle polished method, using angle-polished multimode fiber and optical adhesive, is used to efficiently pump an Yb-doped double-clad fiber laser. The maximum coupling efficiency of 78.6% is achieved by the side-coupler for a multimode fiber with a circular core of 200 um and a double-clad fiber with a 350/400 um D-shaped inner cladding. While laser diodes (LDs) with three side-couplers are simultaneously used as pump sources, maximum output power of 1.38 W and slope efficiency of 48.9% are demonstrated in the fiber laser system.

  7. Fiber optic laser-induced breakdown spectroscopy sensor for molten material analysis

    DOEpatents

    Zhang, Hansheng; Rai, Awadesh K.; Singh, Jagdish P.; Yueh, Fang-Yu

    2004-07-13

    A fiber optic laser-induced breakdown spectroscopy (LIBS) sensor, including a laser light source, a harmonic separator for directing the laser light, a dichroic mirror for reflecting the laser light, a coupling lens for coupling the laser light at an input of a multimode optical fiber, a connector for coupling the laser light from an output of the multimode optical fiber to an input of a high temperature holder, such as a holder made of stainless steel, and a detector portion for receiving emission signal and analyzing LIBS intensities. In one variation, the multimode optical fiber has silica core and silica cladding. The holder includes optical lenses for collimating and focusing the laser light in a molten alloy to produce a plasma, and for collecting and transmitting an emission signal to the multimode optical fiber.

  8. Characterization of a 50-μm-core optical fiber for potential use in Thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard L.; Hutchens, Thomas C.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

    2014-03-01

    Our laboratory is currently studying the Thulium fiber laser (TFL) as a potential alternative laser lithotripter to the standard clinical Holmium:YAG laser. We have previously demonstrated efficient coupling of TFL energy into fibers as small as 100-μm-core-diameter without damage to the proximal end. Although smaller fibers have greater tendency to degrade at the distal tip during lithotripsy, fiber diameters (<= 200 μm) have been shown to increase saline irrigation rates through the working channel of a flexible ureteroscope, maximize ureteroscope deflection, and reduce stone retropulsion during laser lithotripsy. In this study, a 50-μm-core-diameter, 85-μm-outer-diameter fiber is characterized for TFL ablation of human calcium oxalate monohydrate urinary stones, ex vivo. The stone ablation rate was measured to be 70 +/- 22 μg/s for 35-mJ-pulse-energy, 500-μs-pulse-duration, and 50-Hz-pulse-rate. The ureteroscope working channel flow rate including the 50-μm fiber decreased by only 10% with no impairment of ureteroscope deflection. The fiber delivered up to 15.4 +/- 5.9 W under extreme bending (5-mm-radius) conditions. Stone retropulsion and fiber burn-back averaged 201 +/- 336 and 3000 +/- 2600 μm, respectively, after 2 minutes. With further development, Thulium fiber laser lithotripsy using ultra-small, 50-μm-core fibers may introduce new integration and miniaturization possibilities and potentially provide an alternatiμe to conventional Holmium:YAG laser lithotripsy using larger fibers.

  9. Top-hat beam Tm3+-doped fiber laser using an intracavity abrupt taper

    NASA Astrophysics Data System (ADS)

    Zhang, Y. J.; Zhong, F. F.; Wang, Y. Z.

    2011-01-01

    The top-hat beam clad-pumped Tm3+-doped fiber laser was realized simply using an intracavity multi-mode abrupt taper. The ratio of the flat-top diameter to the spot diameter reaches 53%, with a small intensity variation less than 6%, and the top-hat beam's half-divergence angle is only 5.3°. The fiber laser has a maximal output power of 5 W with slope efficiency of 39.7%, pumped by the 792 nm diode laser (LD). The abrupt taper is directly made on the multi-mode double-clad Tm3+-doped fiber near the fiber laser output end with the 0.45 ratio of taper waist diameter to fiber clad diameter, and this fiber end 4% Fresnel reflection is used to be the output coupler. The fiber laser's high reflective coupler is an intracore multi-mode FBG, which is directly written into the multi-mode Tm3+-doped fiber core using femtosecond laser and phase mask, at the other fiber end. The abrupt taper has no obviously influence on the fiber laser output power, and the output laser spectrum.

  10. High power 1018 nm monolithic Yb3+-doped fiber laser and amplifier High power 1018 nm monolithic Yb3+-doped fiber laser and amplifier

    NASA Astrophysics Data System (ADS)

    Xiao, H.; Zhou, P.; Wang, X. L.; Guo, S. F.; Xu, X. J.

    2012-10-01

    In this letter high power monolithic 1018 nm fiber laser and amplifier are presented. The output characteristics of 1018 nm laser with amplified spontaneous emission (ASE) feedback, fiber Bragg gratings (FBG) reflectivity, gain fiber length and other parameters are experimentally investigated. The difference between 1018 and 1064 nm amplification are also compared in experiment. Based on these experimental results, we find viable approaches to improve the laser and amplifier's performances. 85 W 1018 nm fiber laser with a slope efficiency of 71% and 110 W 1018 nm fiber amplifier with the slope efficiency of 77% are achieved, both of which we believe are the highest output at this wavelength that ever reported in open detail.

  11. Fiber optic coupling of a microlens conditioned, stacked semiconductor laser diode array

    DOEpatents

    Beach, Raymond J.; Benett, William J.; Mills, Steven T.

    1997-01-01

    The output radiation from the two-dimensional aperture of a semiconductor laser diode array is efficiently coupled into an optical fiber. The two-dimensional aperture is formed by stacking individual laser diode bars on top of another in a "rack and stack" configuration. Coupling into the fiber is then accomplished using individual microlenses to condition the output radiation of the laser diode bars. A lens that matches the divergence properties and wavefront characteristics of the laser light to the fiber optic is used to focus this conditioned radiation into the fiber.

  12. Fiber optic coupling of a microlens conditioned, stacked semiconductor laser diode array

    DOEpatents

    Beach, R.J.; Benett, W.J.; Mills, S.T.

    1997-04-01

    The output radiation from the two-dimensional aperture of a semiconductor laser diode array is efficiently coupled into an optical fiber. The two-dimensional aperture is formed by stacking individual laser diode bars on top of another in a ``rack and stack`` configuration. Coupling into the fiber is then accomplished using individual microlenses to condition the output radiation of the laser diode bars. A lens that matches the divergence properties and wavefront characteristics of the laser light to the fiber optic is used to focus this conditioned radiation into the fiber. 3 figs.

  13. Kinoform/lens system for injecting a high power laser beam into an optical fiber

    SciTech Connect

    Sweatt, W.C.; Farn, M.W.

    1993-11-01

    A method for injecting a high peak power multimode YAG laser beam into an optical fiber has been developed. The design minimizes the peak irradiance on the fiber`s entrance face and reduces its dependence on the laser`s mode structure and the system alignment. A simple lens and a specially designed kinoform (or binary optics element) operate together to transform a 5 mm diameter laser beam into two concentric ring foci that fit on the 400 {mu}m diameter fiber face.

  14. Tunable optofluidic microring laser based on a tapered hollow core microstructured optical fiber.

    PubMed

    Li, Zhi-Li; Zhou, Wen-Yuan; Luo, Ming-Ming; Liu, Yan-Ge; Tian, Jian-Guo

    2015-04-20

    A tunable optofluidic microring dye laser within a tapered hollow core microstructured optical fiber was demonstrated. The fiber core was filled with a microfluidic gain medium plug and axially pumped by a nanosecond pulse laser at 532 nm. Strong radial emission and low-threshold lasing (16 nJ/pulse) were achieved. Lasing was achieved around the surface of the microfluidic plug. Laser emission was tuned by changing the liquid surface location along the tapered fiber. The possibility of developing a tunable laser within the tapered simplified hollow core microstructured optical fiber presents opportunities for developing liquid surface position sensors and biomedical analysis. PMID:25969082

  15. Fiber laser pumped high power mid-infrared laser with picosecond pulse bunch output.

    PubMed

    Wei, Kaihua; Chen, Tao; Jiang, Peipei; Yang, Dingzhong; Wu, Bo; Shen, Yonghang

    2013-10-21

    We report a novel quasi-synchronously pumped PPMgLN-based high power mid-infrared (MIR) laser with picosecond pulse bunch output. The pump laser is a linearly polarized MOPA structured all fiberized Yb fiber laser with picosecond pulse bunch output. The output from a mode-locked seed fiber laser was directed to pass through a FBG reflector via a circulator to narrow the pulse duration from 800 ps to less than 50 ps and the spectral FWHM from 9 nm to 0.15 nm. The narrowed pulses were further directed to pass through a novel pulse multiplier through which each pulse was made to become a pulse bunch composing of 13 sub-pulses with pulse to pulse time interval of 1.26 ns. The pulses were then amplified via two stage Yb fiber amplifiers to obtain a linearly polarized high average power output up to 85 W, which were then directed to pass through an isolator and to pump a PPMgLN-based optical parametric oscillator via quasi-synchronization pump scheme for ps pulse bunch MIR output. High MIR output with average power up to 4 W was obtained at 3.45 micron showing the feasibility of such pump scheme for ps pulse bunch MIR output. PMID:24150378

  16. A passively mode locked thulium doped fiber laser using bismuth telluride deposited multimode interference

    NASA Astrophysics Data System (ADS)

    Jung, M.; Lee, J.; Song, W.; Lee, J. H.; Shin, W.

    2016-03-01

    We experimentally demonstrate a passively mode-locked thulium doped fiber laser using a bismuth telluride deposited multimode interference (MMI) fiber at a wavelength of 1958 nm. Our MMI based saturable absorber was fabricated by fusion splicing with single mode fiber and null core fiber. The center wavelength and insertion loss of MMI fiber were measured to be ~ 1958 nm and 3.4 dB. We observed a passively mode locked thulium doped fiber laser operating at a wavelength of 1958 nm. The temporal pulse width of output pulses is 4.2 ps with repetition rate of 22.7 MHz.

  17. Double-clad erbium/ytterbium-doped fiber laser with a fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Moghaddam, M. R. A.; Harun, S. W.; Tamjis, M. R.; Ahmad, H.

    2009-08-01

    A double-clad erbium/ytterbium-doped fiber laser (EYDFL) is demonstrated using a fiber Bragg grating (FBG) as wavelength selective filter in a linear cavity resonator. The effect of the FBG's wavelength on the performance of the EYDFL is also investigated. The slope efficiencies of the EYDFL are obtained at 33.7%, 30.9%, and 24.1% for the operating wavelengths of 1553.6, 1557.3, and 1562.8 nm, respectively. The efficiency is higher with a shorter wavelength due to the amplification characteristic of the EYDF which peaks at 1545 nm. At FBG's wavelength of 1553.6 nm, the EYDFL has an output power of 520 mW when pumped at 1700 mW by a 937 nm laser diode. The laser also has a spectral bandwidth of 0.2 nm and signal to noise ratio of more than 25 dB. The threshold power to achieve lasing is measured to be approximately 90 mW for this laser.

  18. 156 micro-J ultrafast Thulium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Wan, Peng; Yang, Lih-Mei; Liu, Jian

    2013-02-01

    A high energy, high power ultrafast Tm doped fiber laser system was successfully developed. Pulse energy of 156 μJ and average power of 15.6 W were achieved. The laser system consisted of a mode-locked 2020 nm seed oscillator and multiple-stage power amplifiers. The seed included 30 m-long dispersion compensating fiber and emitted slightly chirped pulses with spectrum bandwidth of 8 nm. The mode-locking was stable and self-started. Repetition rate of seed oscillator was 2.5 MHz. The seed pulses were stretched with anomalous dispersion fiber to the duration of 320 ps. An AOM was used as a pulse picker to lower the repetition rate. A two-stage pre-amplifier was used to boost the pulse energy to 3 μJ. Pulse energies of up to 156 μJ were obtained from the final stage of power amplifier at a repetition rate of 100 kHz. Pulse durations of 780 fs were obtained after pulse compression. High OSNR and low background noise were also achieved at this low repetition rate.

  19. Switchable multiwavelength thulium-doped fiber ring lasers

    NASA Astrophysics Data System (ADS)

    Zhao, Shui; Lu, Ping; Liu, Deming; Zhang, Jiangshan

    2013-08-01

    Two kinds of thulium-doped fiber ring lasers based on a spatial mode beating filter and comb filtering effect are presented and experimentally demonstrated, which all show multiwavelength laser spectrum around 2 μm. In the implementation of the first type of experiment configuration by the use of a piece of multimode fiber (MMF) as a spatial mode beating filter, dual-,triple-, and quadruple-wavelengths appeared whose extinction noise ratio is 25 dB by adjusting the angle of polarization controller. Different wavelength spaces are obtained by inserting different lengths of MMF. The second type is achieved by inserting a Sagnac loop mirror, which was constructed by a 3-dB coupler and a piece of polarization maintaining fiber. Seven stable wavelengths with channel spacing of 0.65 nm and an extinction ratio of 35 dB was achieved. These systems are simple and easy to construct, which can be useful for 2 μm wavelength-division-multiplexed applications.

  20. High power amplification of a tailored-pulse fiber laser

    NASA Astrophysics Data System (ADS)

    Saby, Julien; Sangla, Damien; Caplette, Stéphane; Boula-Picard, Reynald; Drolet, Mathieu; Reid, Benoit; Salin, François

    2013-02-01

    We demonstrate the amplification of a 1064nm pulse-programmable fiber laser with Large Pitch Rod-Type Fibers of various Mode field diameters from 50 to 70 μm. We have developed a high power fiber amplifier at 1064nm delivering up to 100W/1mJ at 15ns pulses and 30W/300μJ at 2ns with linearly polarized and diffraction limited output beam (M²<1.2). The specific seeder from ESI - Pyrophotonics Lasers used in the experiment allowed us to obtain tailored-pulse programmable on demand at the output from 2ns to 600ns for various repetition rates from 10 to 500 kHz. We could demonstrate square pulses or any other shapes (also multi-pulses) whatever the repetition rate or the pulse duration. We also performed frequency conversion with LBO crystals leading to 50W at 532nm and 25W at 355nm with a diffraction limited output. Similar experiments performed at 1032nm are also reported.

  1. Advances in high-power 9XXnm laser diodes for pumping fiber lasers

    NASA Astrophysics Data System (ADS)

    Skidmore, Jay; Peters, Matthew; Rossin, Victor; Guo, James; Xiao, Yan; Cheng, Jane; Shieh, Allen; Srinivasan, Raman; Singh, Jaspreet; Wei, Cailin; Duesterberg, Richard; Morehead, James J.; Zucker, Erik

    2016-03-01

    A multi-mode 9XXnm-wavelength laser diode was developed to optimize the divergence angle and reliable ex-facet power. Lasers diodes were assembled into a multi-emitter pump package that is fiber coupled via spatial and polarization multiplexing. The pump package has a 135μm diameter output fiber that leverages the same optical train and mechanical design qualified previously. Up to ~ 270W CW power at 22A is achieved at a case temperature ~ 30ºC. Power conversion efficiency is 60% (peak) that drops to 53% at 22A with little thermal roll over. Greater than 90% of the light is collected at < 0.12NA at 16A drive current that produces 3.0W/(mm-mr)2 radiance from the output fiber.

  2. Fiber-laser pumped actively Q-switched Er:LuYAG laser at 1648 nm

    NASA Astrophysics Data System (ADS)

    Yang, X. F.; Wang, Y.; Zhao, T.; Zhu, H. Y.; Shen, D. Y.

    2016-02-01

    We demonstrated an acousto-optic Q-switched 1648 nm Er:LuYAG laser resonantly pumped by a cladding-pumped Er,Yb fiber laser at 1532 nm. Stable Q-switching operation was obtained with the pulse repetition rate (PRR) varying from 200 Hz to 10 kHz. At PRR of 200 Hz, the laser yielded Q-switched pulses with 3.3 mJ pulse energy and 65 ns pulse duration, corresponding to a peak power of 50.7 kW for 10.4 W of incident pump power.

  3. High-power thulium fiber laser ablation of the canine prostate

    NASA Astrophysics Data System (ADS)

    Fried, Nathaniel M.; Murray, Keith E.

    2005-04-01

    The Thulium fiber laser may have several advantages over current urology lasers, including smaller size, more efficient operation, improved spatial beam quality, more precise tissue incision, and operation in pulsed or continuous-wave modes. However, previous laser-tissue interaction studies utilizing the Thulium fiber laser have been limited to laser powers of less than 5 W. This study describes high-power Thulium fiber laser vaporization of the canine prostate, ex vivo. A continuous-wave, 110-watt Thulium fiber laser operating at a wavelength of 1.91 mm, delivered 88.5 +/- 2.3 W of power through a 600-mm-core silica fiber for non-contact vaporization of canine prostates (n=6). The Thulium fiber laser vaporized prostate tissue at a rate of 0.83 +/- 0.11 g/min. The thermal coagulation zone measured 500-2000 mm. The high-power Thulium fiber laser is capable of rapid vaporization and coagulation of the prostate, ex vivo. In vivo animal studies are currently in development for evaluation of the Thulium fiber laser for prostate vaporization and potential treatment of benign prostate hyperplasia.

  4. Fiber Bragg grating interrogation technique for remote sensing (100km) using a hybrid Brillouin-Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Fernandez-Vallejo, M.; Leandro, D.; Loayssa, A.; Lopez-Amo, M.

    2011-05-01

    We propose and demonstrate the feasibility of a novel Fiber Bragg Grating interrogation technique for remote sensing based on the use of a hybrid Raman-Brillouin fiber laser configuration. The laser comprises 100 km of standard singlemode fiber (SMF) in a linear cavity configuration with four Fiber Bragg Gratings (FBGs) arranged in series. The FBGs are used both for the sensing function and for the selection of the lasing wavelengths. A wavelength-swept laser pumps Brillouin gain in the fiber cavity, which is previously set just under lasing threshold by the Raman gain. Furthermore, the sensor signal is detected in the radio frequency domain instead of the optical domain so as to avoid signal to noise ratio limitations produced by Rayleigh scattering. Experimental results demonstrate that the shift of the Bragg wavelength of the FBG sensors can be precisely measured with good signal to noise ration when the FBG are used for temperature sensing.

  5. Comparison of holmium:YAG and thulium fiber lasers for lithotripsy

    NASA Astrophysics Data System (ADS)

    Blackmon, Richard L.; Irby, Pierce B.; Fried, Nathaniel M.

    2010-02-01

    The Holmium:YAG laser is currently the most common laser lithotripter. However, recent experimental studies have demonstrated that the Thulium fiber laser is also capable of vaporizing urinary stones. The high-temperature water absorption coefficient for the Thulium wavelength (μa = 160 cm-1 at λ = 1908 nm) is significantly greater than for the Holmium wavelength (μa = 28 cm-1 at λ = 2120 nm). We hypothesize that this should translate into more efficient laser lithotripsy using the Thulium fiber laser. This study directly compares stone vaporization rates for Holmium and Thulium fiber lasers. Holmium laser radiation pulsed at 3 Hz with 70 mJ pulse energy and 220 μs pulse duration was delivered through a 100-μm-core silica fiber to human uric acid (UA) and calcium oxalate monohydrate (COM) stones, ex vivo (n = 10 each). Thulium fiber laser radiation pulsed at 10 Hz with 70 mJ pulse energy and 1 ms pulse duration was also delivered through a 100-μm fiber for the same sets of 10 stones. For same number of pulses and total energy (126 J) delivered to each stone, mass loss averaged 2.4 +/- 0.6 mg (UA) and 0.7 +/- 0.2 mg (COM) for Holmium laser and 12.6 +/- 2.5 mg (UA) and 6.8 +/- 1.7 (COM) for Thulium fiber laser. UA and COM stone vaporization rates for Thulium fiber laser averaged 5-10 times higher than for Holmium laser at 70 mJ pulse energies. With further development, the Thulium fiber laser may represent an alternative to the conventional Holmium laser for more efficient laser lithotripsy.

  6. Switchable multi-wavelength fiber ring laser based on a compact in-fiber Mach-Zehnder interferometer with photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Chen, W. G.; Lou, S. Q.; Feng, S. C.; Wang, L. W.; Li, H. L.; Guo, T. Y.; Jian, S. S.

    2009-11-01

    Switchable multi-wavelength fiber ring laser with an in-fiber Mach-Zehnder interferometer incorporated into the ring cavity serving as wavelength-selective filter at room temperature is demonstrated. The filter is formed by splicing a section of few-mode photonic crystal fiber (PCF) and two segments of single mode fiber (SMF) with the air-holes on the both sides of PCF intentionally collapsed in the vicinity of the splices. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-, dual- and triple-wavelength lasing operations by exploiting polarization hole burning (PHB) effect.

  7. Reflectivity of transient Bragg reflection gratings in fiber laser with laser-wavelength self-sweeping: erratum.

    PubMed

    Peterka, P; Honzátko, P; Koška, P; Todorov, F; Aubrecht, J; Podrazký, O; Kašík, I

    2016-07-11

    This erratum presents a correction to the computed reflection spectra of transient fiber Bragg gratings that are spontaneously built-up in the ytterbium-doped fiber of the fiber laser with laser wavelength self-sweeping. The corrected spectra have high reflectivity reaching values up to 100%. Therefore, they still more support the conclusion drawn in the original paper that self-sweeping is an important mechanism for triggering the self-Q-switched regime with giant pulse generation. PMID:27410889

  8. Soliton Thulium-Doped Fiber Laser With Carbon Nanotube Saturable Absorber

    PubMed Central

    Kieu, K.; Wise, F. W.

    2011-01-01

    We report stabilization of a thulium–holmium codoped fiber soliton laser with a saturable absorber based on carbon nanotubes. The laser generates transform-limited 750-fs pulses with 0.5-nJ energy. PMID:21731403

  9. Soliton Thulium-Doped Fiber Laser With Carbon Nanotube Saturable Absorber.

    PubMed

    Kieu, K; Wise, F W

    2009-02-01

    We report stabilization of a thulium-holmium codoped fiber soliton laser with a saturable absorber based on carbon nanotubes. The laser generates transform-limited 750-fs pulses with 0.5-nJ energy. PMID:21731403

  10. An all-fiber high-energy cladding-pumped 93 nanosecond Q-switched fiber laser using an Y 3+-doped fiber saturable absorber

    NASA Astrophysics Data System (ADS)

    Moore, Sean W.; Patterson, Brian D.; Soh, Daniel B.; Bisson, Scott E.

    2014-03-01

    We report an all-fiber passively Q-switched laser using a large mode area (LMA) Yb3+ -doped fiber claddingpumped at 915 nm and an unpumped single-mode (SM) Yb3+-doped fiber as the saturable absorber (SA). The saturable absorber SM fiber and LMA gain fiber were coupled with a fiber taper designed to match the fundamental spatial mode of the LMA fiber and the expanded LP01 mode of the single mode fiber. The amplified spontaneous (ASE) intensity propagating in the single mode SA saturates the absorption before the onset of gain depletion in the pumped fiber, switching the fiber cavity to a high Q-state and producing a pulse. Using this scheme we demonstrate a Q-switched all-fiber oscillator with 32 μJ 93 ns pulses at 1030 nm. The associated peak power is nearly two orders of magnitude larger than that reported in previous experimental studies using a single Yb+3 saturable absorber fiber. The pulse energy was amplified to 0.230 mJ using an Yb3+-doped cladding pumped fiber amplifier fusion spliced to the fiber oscillator, increasing the energy by eight fold while preserving the all-fiber architecture.

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  13. Influence of spectral properties of wavelength-locked and wavelength-unlocked diode laser on fiber laser performances

    NASA Astrophysics Data System (ADS)

    Huang, Zhihua; Tang, Xuan; Zhao, Pengfei; Li, Zebiao; Li, Chengyu; Li, Qi; Guo, Chao; Lin, Honghuan; Wang, Jianjun; Jing, Feng

    2016-07-01

    The influence of the spectral properties of laser diode (LD) pump source, i.e. central wavelength and linewidth, on the fiber laser performances are studied. The absorption degradation ratio (ADR) is introduced and evaluated as a guide for pump selection and fiber laser design. The spectra of wavelength-locked and wavelength-unlocked LDs are measured and they are used for fiber laser amplification. The results show that the efficiency of the wavelength-locked LDs is higher than that of the wavelength-unlocked LDs at full current but the residual pump power of wavelength-locked LDs can be much higher at lower current because of the side band.

  14. Applications of optical fiber to remote laser fluorescence analysis

    NASA Astrophysics Data System (ADS)

    Kim, Cheol Jung; Shin, Jang Soo; Lee, Sang Mock; Kim, Jeong Moog; Kim, Duk Heon; Hong, Seok Kyung

    1991-12-01

    Fluorescence analysis using time-resolved laser fluorimetry was used for trace uranium analysis because this method shows high sensitivity and low detection limit and is less matrix dependent than any other fluorimetric measurement. By this time, the uranium analyses in the solution of reprocessing process or high radioactive area were primarily analyzed by sampling of the solution, but recently, a study on a remote uranium fluorescence analysis using optical fiber was setting out based on the development of an optical fiber with radiation resistivity and of an advanced laser excitation source. Laser fluorimetry developed by our laboratory for trace uranium analyses in uranium handling process or in urine samples of workers in a nuclear facility was used in our institute since 1988. A development of the system for remote control of uranium fluorescence analysis will be expected to contribute to an on-line uranium concentration monitoring in the cooling water of reconversion stream. The information related to fluorescence analyses and remote fluorescence monitoring methods established by foreign countries and our laboratory were summarized. A future research direction for remote on-line monitoring of uranium in conversion or reconversion processes was presented.

  15. Monolithic mid-infrared fiber lasers for the 2-4 μm spectral region

    NASA Astrophysics Data System (ADS)

    Fortin, Vincent; Bernier, Martin; Caron, Nicolas; Faucher, Dominic; El-Amraoui, Mohammed; Messaddeq, Younès.; Vallée, Réal

    2013-03-01

    A growing number of applications are calling for compact laser sources operating in the mid-infrared spectral region. A review of our recent work on monolithic fiber lasers based either on the use of rare-earth fluoride fibers or on Raman gain in both fluoride and chalcogenide glass fibers is presented. Accordingly, an erbium-doped double clad fluoride glass all-fiber laser operating in the vicinity of 3 μm is shown. In addition, we present recent results on the first demonstrations of both fluoride and chalcogenide Raman fiber lasers operating at 2.23 μm and 3.34 μm, respectively. It is shown that based on this approach, monolithic fiber lasers could be developed to cover the whole 2-4 μm spectral band.

  16. Fiber lasers and amplifiers for science and exploration at NASA Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Abshire, James; Allan, Graham R.; Stephen Mark

    2005-01-01

    We discuss present and near-term uses for high-power fiber lasers and amplifiers for NASA- specific applications including planetary topography and atmospheric spectroscopy. Fiber lasers and amplifiers offer numerous advantages for both near-term and future deployment of instruments on exploration and science remote sensing orbiting satellites. Ground-based and airborne systems provide an evolutionary path to space and a means for calibration and verification of space-borne systems. We present experimental progress on both the fiber transmitters and instrument prototypes for ongoing development efforts. These near-infrared instruments are laser sounders and lidars for measuring atmospheric carbon dioxide, oxygen, water vapor and methane and a pseudo-noise (PN) code laser ranging system. The associated fiber transmitters include high-power erbium, ytterbium, neodymium and Raman fiber amplifiers. In addition, we will discuss near-term fiber laser and amplifier requirements and programs for NASA free space optical communications, planetary topography and atmospheric spectroscopy.

  17. All-fiber ultra-narrow linewidth 50 pm Tm3+-doped double-clad fiber laser at 1948 nm

    NASA Astrophysics Data System (ADS)

    Jing, T.; Zhang, Y. J.; Zhong, F. F.

    2011-01-01

    A high stability all-fiber LD-clad-pumped Tm3+-doped fiber laser was reported. The fiber laser had the ultra-narrow linewidth 50 pm at 1.948 μm with the maximal output power of 12.8 W. The slope efficiency was 28.9%, and threshold was 5.7 W. The double-clad Tm3+-doped fiber core was multi-mode, which had a demission of 25/250 μm with the core NA of 0.1 and inner-clad NA of 0.46. The high reflectivity coupler FBG was directly written into the single-mode passive photosensitive optical fiber core, which had a core diameter of 15 μm and NA of 0.1. The cavity was build-up by the high reflectivity FBG and the output fiber end Fresnel reflectivity.

  18. Tunable and switchable multi-wavelength fiber laser based on semiconductor optical amplifier and twin-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Kim, Bongkyun; Han, Jihee; Chung, Youngjoo

    2012-02-01

    Multi-wavelength fiber lasers have attracted a lot of interest, recently, because of their potential applications in wavelength-division-multiplexing (WDM) systems, optical fiber sensing, and fiber-optics instruments, due to their numerous advantages such as multiple wavelength operation, low cost, and compatibility with the fiber optic systems. Semiconductor optical amplifier (SOA)-based multi-wavelength fiber lasers exhibit stable operation because of the SOA has the property of primarily inhomogeneous broadening and thus can support simultaneous oscillation of multiple lasing wavelengths. In this letter, we propose and experimentally demonstrate a switchable multi-wavelength fiber laser employing a semiconductor optical amplifier and twin-core photonic crystal fiber (TC-PCF) based in-line interferometer comb filter. The fabricated two cores are not symmetric due to the associated fiber fabrication process such as nonuniform heat gradient in furnace and asymmetric microstructure expansion during the gas pressurization which results in different silica strut thickness and core size. The induced asymmetry between two cores considerably alters the linear power transfer, by seriously reducing it. These nominal twin cores form effective two optical paths and associated effective refractive index difference. The in-fiber comb filter is effectively constructed by splicing a section of TC-PCF between two single mode fibers (SMFs). The proposed laser can be designed to operate in stable multi-wavelength lasing states by adjusting the states of the polarization controller (PC). The lasing modes are switched by varying the state of PC and the change is reversible. In addition, we demonstrate a tunable multi-wavelength fiber laser operation by applying temperature changes to TC-PCF in the multi-channel filter.

  19. Green fiber lasers: An alternative to traditional DPSS green lasers for flow cytometry

    PubMed Central

    Telford, William G.; Babin, Sergey A.; Khorev, Serge V.; Rowe, Stephen H.

    2009-01-01

    Green and yellow diode-pumped solid state (DPSS) lasers (532 and 561 nm) have become common fixtures on flow cytometers, due to their efficient excitation of phycoerythrin (PE) and its tandems, and their ability to excite an expanding array of expressible red fluorescent proteins. Nevertheless, they have some disadvantages. DPSS 532 nm lasers emit very close to the fluorescein bandwidth, necessitating optical modifications to permit detection of fluorescein and GFP. DPSS 561 nm lasers likewise emit very close to the PE detection bandwidth, and also cause unwanted excitation of APC and its tandems, requiring high levels of crossbeam compensation to reduce spectral overlap into the PE tandems. In this paper, we report the development of a new generation of green fiber lasers that can be engineered to emit in the range between 532 and 561 nm. A 550 nm green fiber laser was integrated into both a BD LSR II™ cuvette and FACSVantage DiVa™ jet-in-air cell sorter. This laser wavelength avoided both the fluorescein and PE bandwidths, and provided better excitation of PE and the red fluorescent proteins DsRed and dTomato than a power-matched 532 nm source. Excitation at 550 nm also caused less incidental excitation of APC and its tandems, reducing the need for crossbeam compensation. Excitation in the 550 nm range therefore proved to be a good compromise between 532 and 561 nm sources. Fiber laser technology is therefore providing the flexibility necessary for precisely matching laser wavelengths to our flow cytometry applications. PMID:19777600

  20. Direct infrared femtosecond laser inscription of chirped fiber Bragg gratings.

    PubMed

    Antipov, Sergei; Ams, Martin; Williams, Robert J; Magi, Eric; Withford, Michael J; Fuerbach, Alexander

    2016-01-11

    We compare and contrast novel techniques for the fabrication of chirped broadband fiber Bragg gratings by ultrafast laser inscription. These methods enable the inscription of gratings with flexible period profiles and thus tailored reflection and dispersion characteristics in non-photosensitive optical fibers. Up to 19.5 cm long chirped gratings with a spectral bandwidth of up to 30 nm were fabricated and the grating dispersion was characterized. A maximum group delay of almost 2 ns was obtained for linearly chirped gratings with either normal or anomalous group velocity dispersion, demonstrating the potential for using these gratings for dispersion compensation. Coupling to cladding modes was reduced by careful design of the inscribed modification features. PMID:26832235