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Sample records for bandgap fiber laser

  1. Electrically tunable liquid crystal photonic bandgap fiber laser

    NASA Astrophysics Data System (ADS)

    Olausson, Christina B.; Scolari, Lara; Wei, Lei; Noordegraaf, Danny; Weirich, Johannes; Alkeskjold, Thomas T.; Hansen, Kim P.; Bjarklev, Anders

    2010-02-01

    We demonstrate electrical tunability of a fiber laser using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an all-spliced laser cavity based on a liquid crystal photonic bandgap fiber mounted on a silicon assembly, a pump/signal combiner with single-mode signal feed-through and an ytterbium-doped photonic crystal fiber. The laser cavity produces a single-mode output and is tuned in the range 1040- 1065 nm by applying an electric field to the silicon assembly.

  2. Large Mode Area Yb-Doped Photonic Bandgap Fiber Lasers

    DTIC Science & Technology

    2015-02-08

    ABSTRACT 16. SECURITY CLASSIFICATION OF: All-solid photonic bandgap fibers (PBGF) can be spectrally tailored to suppress amplified spontaneous emission...ASE) and stimulated Raman scattering (SRS). Furthermore, this type of fiber is attractive for realizing high-power narrow-linewidth amplifiers as...area Yb-doped photonic bandgap fiber lasers Report Title All-solid photonic bandgap fibers (PBGF) can be spectrally tailored to suppress amplified

  3. Reversed dispersion slope photonic bandgap fibers for broadband dispersion control in femtosecond fiber lasers.

    PubMed

    Várallyay, Z; Saitoh, K; Fekete, J; Kakihara, K; Koshiba, M; Szipocs, R

    2008-09-29

    Higher-order-mode solid and hollow core photonic bandgap fibers exhibiting reversed or zero dispersion slope over tens or hundreds of nanometer bandwidths within the bandgap are presented. This attractive feature makes them well suited for broadband dispersion control in femtosecond pulse fiber lasers, amplifiers and optical parametric oscillators. The canonical form of the dispersion profile in photonic bandgap fibers is modified by a partial reflector layer/interface placed around the core forming a 2D cylindrical Gires-Tournois type interferometer. This small perturbation in the index profile induces a frequency dependent electric field distribution of the preferred propagating higher-order-mode resulting in a zero or reversed dispersion slope.

  4. Similariton fiber laser with a hollow-core photonic bandgap fiber for dispersion control

    NASA Astrophysics Data System (ADS)

    Ruehl, A.; Prochnow, O.; Engelbrecht, M.; Wandt, D.; Kracht, D.

    2007-05-01

    We report on an ytterbium-doped similariton fiber ring laser with a hollow-core photonic bandgap fiber for intracavity dispersion control. The oscillator is hybrid mode locked with a saturable Bragg reflector and by nonlinear polarization evolution. This scheme allows for an exact adjustment of the transmission characteristic to avoid the formation of bunched noiselike pulses while the self-starting characteristic is preserved. The oscillator generates highly stretched similaritons at 1025 nm with a pulse energy above 1n J at a repetition rate of 21.9 MHz.

  5. A new modality for minimally invasive CO2 laser surgery: flexible hollow-core photonic bandgap fibers.

    PubMed

    Shurgalin, Max; Anastassiou, Charalambos

    2008-01-01

    Carbon dioxide (CO2) lasers have become one of the most common surgical lasers due to excellent tissue interaction properties that offer precise control of cutting and ablation depth, minimal thermal damage to surrounding tissue, and good hemostasis. However, realization of the benefits offered by using surgical CO2 lasers in many endoscopic, minimally invasive surgical procedures has been inhibited by the absence of reliable, flexible fiber laser beam delivery systems. Recently, novel hollow-core photonic bandgap optical fibers for CO2 lasers were developed that offer high flexibility and mechanical robustness with good optical performance under tight bends. These fibers can be used through rigid and flexible endoscopes and various handpieces and will allow surgeons to perform delicate and precise laser surgery procedures in a minimally invasive manner. This paper describes the basic design of laser beam delivery system, different surgical fiber designs and their characteristics, and usage with existing surgical CO2 laser models. A few examples of successful CO2 laser surgeries performed with these fibers are presented.

  6. Management of the high-order mode content in large (40 microm) core photonic bandgap Bragg fiber laser.

    PubMed

    Gaponov, D A; Février, S; Devautour, M; Roy, P; Likhachev, M E; Aleshkina, S S; Salganskii, M Y; Yashkov, M V; Guryanov, A N

    2010-07-01

    Very large-mode-area Yb(3+)-doped single-mode photonic bandgap (PBG) Bragg fiber oscillators are considered. The transverse hole-burning effect is numerically modeled, which helps properly design the PBG cladding and the Yb(3+)-doped region for the high-order mode content to be carefully controlled. A ratio of the Yb(3+)-doped region diameter to the overall core diameter of 40% allows for single-mode emission, even for small spool diameters of 15 cm. Such a fiber was manufactured and subsequently used as the core element of a cw oscillator. Very good beam quality parameter M(2)=1.12 and slope efficiency of 80% were measured. Insensitivity to bending, exemplified by the absence of temporal drift of the beam, was demonstrated for curvature diameter as small as 15 cm.

  7. 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.

  8. 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.

  9. Polarizing 50micrometers Core Yb-Doped Photonic Bandgap Fiber

    DTIC Science & Technology

    2015-02-08

    add ref]. Here, we demonstrate a 50µm core Yb- doped polarizing photonic bandgap fiber (PBF) for single-polarization operation 1. REPORT DATE (DD-MM...19-08-2015 Approved for public release; distribution is unlimited. Polarizing 50µm core Yb- doped photonic bandgap fiber The views, opinions and/or...29631 -0946 ABSTRACT Polarizing 50µm core Yb- doped photonic bandgap fiber Report Title Polarizing optical fibers are an important component for building

  10. 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.

  11. 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.

  12. Spectral characterization of a photonic bandgap fiber for sensing applications.

    PubMed

    Aref, S Hashem; Amezcua-Correac, Rodrigo; Carvalho, Joel P; Frazão, Orlando; Santos, José L; Araújo, Francisco M; Latifi, Hamid; Farahi, Faramarz; Ferreira, Luis A; Knight, Jonathan C

    2010-04-01

    We study the measurand-induced spectral shift of the photonic bandgap edge of a hollow-core photonic crystal fiber. The physical measurands considered are strain, temperature, curvature, and twist. A noticeable sensitivity to strain, temperature, and twist is observed, with a blueshift to increase strain and twist. An increase in temperature induces a redshift. On the other hand, curvature has no observable effect on the spectral position of the photonic bandgap edge.

  13. 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.

  14. 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.

  15. Resonant Biochemical Sensors Based on Photonic Bandgap Waveguides and Fibers

    NASA Astrophysics Data System (ADS)

    Skorobogatiy, Maksim

    I describe photonic bandgap (PBG) fiber-based resonant optical sensors of analyte's refractive index which have recently invoked strong interest due to the development of novel fiber types and of techniques for the activation of fiber microstructure with functional materials. Particularly, I consider two sensors types. One employs hollow-core photonic bandgap fibers where the core-guided mode is confined in the analyte's filled core through resonant effect in the surrounding periodic reflector. The other employs metallized photonic bandgap waveguides and fibers, where core-guided mode is phase-matched with a plasmon wave propagating at the fiber/analyte interface. In resonant sensors, one typically employs fibers with strongly nonuniform spectral transmission characteristics that are sensitive to changes in the real part of the analyte's refractive index. Moreover, if narrow absorption lines are present in the analyte transmission spectrum, due to Kramers-Kronig relation, this will also result in strong variation in the real part of the refractive index in the vicinity of an absorption line. Therefore, resonant sensors allow detection of minute changes both in the real part of the analyte's refractive index ( {10^{ - 6}} - {10^{ - 4}}{ RIU} ) and in the imaginary part of the analyte's refractive index in the vicinity of absorption lines. Although the operational principle of almost all PBG fiber-based sensors relies on strong sensitivity of the PBG fiber losses to the value of the analyte's refractive index, particular transduction mechanisms for biodetection vary significantly. Finally, I detail various sensor implementations, modes of operation, as well as analysis of sensitivities for some of the common transduction mechanisms for biosensing applications.

  16. Midinfrared sensors meet nanotechnology: Trace gas sensing with quantum cascade lasers inside photonic band-gap hollow waveguides

    NASA Astrophysics Data System (ADS)

    Charlton, Christy; Temelkuran, Burak; Dellemann, Gregor; Mizaikoff, Boris

    2005-05-01

    An integrated midinfrared sensing system for trace level (ppb) gas analysis combining a quantum cascade laser with an emission frequency of 10.3μm with a frequency matched photonic band-gap hollow core waveguide has been developed, demonstrating the sensing application of photonic band-gap fibers. The photonic band-gap fiber simultaneously acts as a wavelength selective waveguide and miniaturized gas cell. The laser emission wavelength corresponds to the vibrational C-H stretch band of ethyl chloride gas. This sensing system enabled the detection of ethyl chloride at concentration levels of 30ppb (v/v) with a response time of 8s probing a sample volume of only 1.5mL in a transmission absorption measurement within the photonic band-gap hollow core waveguide, which corresponds to a sensitivity improvement by three orders of magnitude compared to previously reported results obtained with conventional hollow waveguides.

  17. All-fiber chirped pulse amplification using highly-dispersive air-core photonic bandgap fiber.

    PubMed

    de Matos, C; Taylor, J; Hansen, T; Hansen, K; Broeng, J

    2003-11-03

    We show, for the first time to our knowledge, all-fiber chirped pulse amplification using an air-core photonic bandgap fiber. Pulses from a wavelength- and duration-tunable femtosecond/picosecond source at 10 GHz were dispersed in 100 m of dispersion compensating fiber before being amplified in an erbium-doped fiber amplifier and subsequently recompressed in 10 m of the anomalously dispersive photonic bandgap fiber. Pulses as short as 1.1 ps were obtained. As air-core fibers present negligible nonlinearity, the presented configuration can potentially be used to obtain ultra-high pulse peak powers. A study of the air-core fiber dispersion and dispersion slope is also presented.

  18. 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.

  19. Diode Pumped Fiber Laser

    DTIC Science & Technology

    1983-07-01

    acousto - optic beam deflector for greater absolute accuracy. The detection system was also upgraded to a response time of • 1 usec. The... 2 C. SUMMARY OF RESULTS.., 3 D . GENERAL PLAN 5 II. Nd:YAG FIBER PREPARATION 7 A. FIBER GROWTH 7 B. PHYSICAL PROPERTIES OF Nd:YAG...A. INTRODUCTION 25 B. GENERAL FORMALISM 26 C. FREE-SPACE LASERS 35 D . FIBER LASERS 43 1. Fiber Laser Configuration 43 2 . F

  20. Raman fiber lasers

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  1. Polarizing Ytterbium-Doped all-Solid Photonic Bandgap Fiber with 1150 micrometers2 Effective Mode Area

    DTIC Science & Technology

    2015-02-11

    0704-0188 3. DATES COVERED (From - To) - UU UU UU UU Approved for public release; distribution is unlimited. Polarizing ytterbium- doped all-solid...photonic bandgap fiber with ~1150µm2 effective mode area We demonstrate an Yb- doped polarizing all-solid photonic bandgap fiber for single-polarization... doped all-solid photonic bandgap fiber with ~1150µm2 effective mode area Report Title We demonstrate an Yb- doped polarizing all-solid photonic bandgap

  2. 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.

  3. 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.

  4. Femtosecond laser ablation of wide band-gap materials

    NASA Astrophysics Data System (ADS)

    Takayama, Hidetoshi; Maruyama, Toshiro

    2012-11-01

    A plasma model proposed by Jiang and Tsai was applied to the experimental results for wide band-gap materials. The model fairly well predicted the laser-fluence dependences of the hole depth and diameter. The analytical threshold fluence represented the pulse-duration dependence very well. However, the model was insufficient to express the crater shape and to predict the threshold fluence. Deviations from the measurements suggest that the effect of ponderomotive force should be taken into account to improve the expression for the crater shape and that the surface energy needed to be additionally taken into account to predict the threshold fluence quantitatively.

  5. 167 W, power scalable ytterbium-doped photonic bandgap fiber amplifier at 1178 nm.

    PubMed

    Olausson, C B; Shirakawa, A; Chen, M; Lyngsø, J K; Broeng, J; Hansen, K P; Bjarklev, A; Ueda, K

    2010-08-02

    An ytterbium-doped photonic bandgap fiber amplifier operating at the long wavelength edge of the ytterbium gain band is investigated for high power amplification. The spectral filtering effect of the photonic bandgap efficiently suppresses amplified spontaneous emission at the conventional ytterbium gain wavelengths and thus enables high power amplification at 1178 nm. A record output power of 167 W, a slope efficiency of 61% and 15 dB saturated gain at 1178 nm have been demonstrated using the ytterbium-doped photonic bandgap fiber.

  6. Femtosecond Laser Processing of Wide Bandgap Semiconductors and Their Applications

    NASA Astrophysics Data System (ADS)

    Phillips, Katherine Collett Furr

    This thesis explores the production, characterization, and water oxidation efficiency of wide bandgap semiconductors made through femtosecond-laser irradiation of various materials. Our investigation focuses on three main aspects: 1) producing titanium dioxide (TiO2) from titanium metal, 2) using our laser-made materials in a photoelectrochemical cell for water oxidation, and 3) utilizing the femtosecond laser to create a variety of other mixed metal oxides for further water oxidation studies and biological applications. We first discuss producing TiO2 and titanium nitride. We report that there is chemical selectivity at play in the femtosecond laser doping process so not all dopants in the surrounding atmosphere will necessarily be incorporated. We then show that the material made from laser-irradiation of titanium metal, when annealed, has a three-fold enhancement in overall water oxidation when irradiated with UV light. We attribute this enhancement through various material characterization methods to the creation of a more pure form of rutile TiO2 with less defects. We then present a variety of studies done with doping both TiO2 and other oxides with broadband photoelectrochemistry and offer that the dopant incorporation hurts the overall water oxidation rate. Lastly, we use the laser-treated titanium to test cell adhesion and viability. Our results demonstrate an ability to femtosecond-laser process semiconductors to produce materials that no one has made previously and study their properties using collaborations across chemistry and biology, yielding true interdisciplinary research.

  7. Tunable random fiber laser

    SciTech Connect

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

    2011-08-15

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

  8. Advanced specialty fiber designs for high power fiber lasers

    NASA Astrophysics Data System (ADS)

    Gu, Guancheng

    deviation from circular fiber outer shape may be an effective method to mitigate HOM loss reduction from coherent reflection from fiber outer boundary. In an all-solid photonic bandgap fiber, modes are only guided due to anti-resonance of cladding photonic crystal lattice. This provides strongly mode-dependent guidance, leading to very high differential mode losses, which is essential for lasing far from the gain peak and suppression of stimulated Raman scattering. We will show that all-solid photonic bandgap fibers with effective mode area of 920microm2 can be made with excellent higher order mode suppression. We then demonstrate a 50microm-core-diameter Yb-doped all-solid photonic bandgap fiber laser. 75W output power has been generated with a diffraction-limited beam and an efficiency of 70% relative to the launched pump power. We have also experimentally confirmed that a robust single-mode regime exists near the high frequency edge of the bandgap. 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 further scaled up the mode area and have successfully demonstrated a single-mode photonic bandgap fiber with record effective mode area of 2650microm2. 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. We have also experimentally validated one of the designs. M 2<1.08 across the transmission band was demonstrated. Lowering quantum defect heating is another approach to mitigate mode instability. Highly-efficient high-power fiber lasers operating at wavelength below 1020nm are critical for tandem-pumping in >10kW fiber lasers to provide high pump

  9. Detailed study of macrobending effects in a wide transmission bandwidth hollow-core photonic bandgap fiber

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Sandoghchi, S. R.; Numkam, E.; Bradley, T. D.; Hayes, J. R.; Wheeler, N. V.; Jasion, G.; Gray, D. R.; Poletti, F.; Petrovich, M. N.; Richardson, D. J.

    2016-04-01

    We study in detail the macrobending effects in a wide transmission bandwidth (~200nm) 19 cell hollow-core photonic bandgap fiber operating at 1550nm. Our results indicate low bend sensitivity over a ~130nm wide interval within the transmission window, with negligible loss (<0.1dB) for bending radii down to 5mm. The "red shift" and "blue shift" of the bandgap edge have been observed at the short and long wavelength edges, respectively. The cutoff wavelengths where air-guiding modes stop guiding can be extracted from the bending loss spectra, which matches well with the simulated effective refractive index map of such fiber.

  10. Solid-Core Photonic Bandgap Fibers for Cladding-Pumped Raman Amplification

    DTIC Science & Technology

    2011-06-03

    simulated. ©2011 Optical Society of America OCIS codes: (140.3510) Lasers , fiber ; (140.3550) Lasers , Raman; (290.5910) Scattering, stimulated Raman...the scalability of diffraction-limited fiber lasers and amplifiers to high average power,” Opt. Express 16(17), 13240–13266 (2008), http...doped fiber laser with true single-mode output using W-type structure,” in Conference on Lasers and Electro-Optics, (Optical Society of America, 2006

  11. 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.

  12. Reflection-induced bias error in an air-core photonic bandgap fiber optic gyroscope.

    PubMed

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

    2016-01-15

    Analysis of the bias error induced by reflections in an air-core photonic bandgap fiber gyroscope is performed by both simulation and experiment. The bias error is sinusoidally periodic under modulation, and its intensity is related to the relative positions of the reflection points. A simple and effective method for the suppression of the error is proposed, and it has been verified experimentally.

  13. Monolithic blue upconversion fiber laser

    NASA Astrophysics Data System (ADS)

    Gaebler, Volker; Eichler, Hans J.

    2002-06-01

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

  14. Investigation of residual core ellipticity induced nonreciprocity in air-core photonic bandgap fiber optical gyroscope.

    PubMed

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

    2014-11-03

    Air-core photonic bandgap fiber (PBF) is an excellent choice for fiber optic gyroscope owing to its incomparable adaptability of environment. Strong and continuous polarization mode coupling is found in PBFs with an average intensity of ~-30 dB, but the coupling arrives at the limit when the maximum optical path difference between the primary waves and the polarization-mode-coupling-induced secondary waves reaches ~10mm, which is corresponding to the PBF length of ~110 m according to the birefringence in the PBF. Incident light with the low extinction ratio (ER) can suppress the birth of the polarization-mode-coupling-induced secondary waves, but the low-ER light obtained by the conventional Lyot depolarizers does not work here. Consequently, a large nonreciprocity and a bias error of ~13°/h are caused in the air-core photonic bandgap fiber optical gyroscope (PBFOG) with a PBF coil of ~268 m.

  15. 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.

  16. Diode Pumped Fiber Laser.

    DTIC Science & Technology

    1987-08-01

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

  17. Discrete bisoliton fiber laser

    PubMed Central

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

    2016-01-01

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

  18. Discrete bisoliton fiber laser

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  19. 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. )

  20. Generation of megawatt optical solitons in hollow-core photonic band-gap fibers.

    PubMed

    Ouzounov, Dimitre G; Ahmad, Faisal R; Müller, Dirk; Venkataraman, Natesan; Gallagher, Michael T; Thomas, Malcolm G; Silcox, John; Koch, Karl W; Gaeta, Alexander L

    2003-09-19

    The measured dispersion of a low-loss, hollow-core photonic band-gap fiber is anomalous throughout most of the transmission band, and its variation with wavelength is large compared with that of a conventional step-index fiber. For an air-filled fiber, femtosecond self-frequency--shifted fundamental solitons with peak powers greater than 2megawatts can be supported. For Xe-filled fibers, nonfrequency-shifted temporal solitons with peak powers greater than 5.5 megawatts can be generated, representing an increase in the power that can be propagated in an optical fiber of two orders of magnitude. The results demonstrate a unique capability to deliver high-power pulses in a single spatial mode over distances exceeding 200 meters.

  1. 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.

  2. Transmission and temperature sensing characteristics of a selectively liquid-filled photonic-bandgap-fiber-based Sagnac interferometer

    NASA Astrophysics Data System (ADS)

    Zheng, Xibao; Liu, Yan-ge; Wang, Zhi; Han, Tingting; Wei, Chengli; Chen, Jinjie

    2012-04-01

    A selectively liquid-filled photonic-bandgap-fiber-based Sagnac interferometer is proposed and demonstrated. Extraordinary transmission and sensing characteristics of the interferometer are observed and investigated theoretically and experimentally. Due to the unique modal and group birefringence characteristics of the material-infiltrated photonic bandgap fiber, the temperature sensitivity of the interference peaks strongly depends on the wavelength. Furthermore, the interference peaks at the two edges of the bandgap appear to shift in the opposite direction alongside changes in the temperature, providing a method of achieving two- or multi-parameter simultaneous sensing measurement with a compact structure.

  3. Gaussian Filtering with Tapered Oil-Filled Photonic Bandgap Fibers

    NASA Astrophysics Data System (ADS)

    Brunetti, A. C.; Scolari, L.; Weirich, J.; Eskildsen, L.; Bellanca, G.; Bassi, P.; Bjarklev, A.

    2008-10-01

    A tunable Gaussian filter based on a tapered oil-filled photonic crystal fiber is demonstrated. The filter is centered at λ = 1364 nm with a bandwidth (FWHM) of 237nm. Tunability is achieved by changing the temperature of the filter. A shift of 210nm of the central wavelength has been observed by increasing the temperature from 25 °C to 100 °C. The measurements are compared to a simulated spectrum obtained by means of a vectorial Beam Propagation Method model.

  4. Fiber lasers for material processing

    NASA Astrophysics Data System (ADS)

    Shiner, Bill

    2005-03-01

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

  5. Hollow-core photonic bandgap fibers for orbital angular momentum applications

    NASA Astrophysics Data System (ADS)

    Li, H.; Ren, G.; Gao, Y.; Zhu, B.; Wang, J.; Yin, B.; Jian, S.

    2017-04-01

    We present a study on the potential and challenges of guiding orbital angular momentum (OAM) modes in hollow-core photonic bandgap fibers (HC-PBGFs). Two 19-cell HC-PBGFs with different structural parameters are comparably investigated. The OAM mode properties in a 37-cell HC-PBGF are also discussed to explore the scalability of OAM states. Characteristics of vector modes and OAM modes are comprehensively analyzed with numerical simulations. The results show HC-PBGF with a larger core could effectively support more OAM modes with lower confinement loss and a larger effective area. In addition, HC-PBGF with a deeper and wider photonic bandgap is advantageous for achieving low crosstalk OAM transmission over a broader band-width. 19-cell HC-PBGFs could support OAM modes with purity beyond 0.9, and the value can be further improved by exploiting the 37-cell HC-PBGF.

  6. Hollow-core photonic bandgap fiber gas sensor with high sensitivity and fast response

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    The effects of modal interference (MI) on the performance of hollow-core photonic bandgap fiber (HC-PBF) gas sensors are investigated. By optimizing mode launch, applying wavelength modulation with proper modulation parameters as well as appropriate digital signal processing, an estimated lower detection limit of <1 ppmv acetylene is achieved with 13-m long HC-PBF. The impacts of drilling side-hole on the MI and response time are also studied. With a 62-cm long sensing HC-PBF drilled with multiple side-holes, an acetylene sensor with a lower detection limit of 11 ppmv and a recovery time of 2 minute is demonstrated.

  7. 503MHz repetition rate femtosecond Yb: fiber ring laser with an integrated WDM collimator.

    PubMed

    Wang, Aimin; Yang, Hongyu; Zhang, Zhigang

    2011-12-05

    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.

  8. 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

  9. Dissipative solitons in fiber lasers

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  10. 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.

  11. 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.

  12. High Power Fiber Lasers

    DTIC Science & Technology

    2012-08-02

    mode, purity of polarization state, minimization of nonlinear effects, compatibility with all-fiber pumps, and high temperature buffer coatings. Over...nonlinear effects, compatibility with all-fiber pumps, and high temperature buffer coatings. Over the duration of this program the most significant...minimization of nonlinear effects, compatibility with all-fiber pumps, and high temperature buffer coatings. Over the duration of this program the most

  13. 2 micron femtosecond fiber laser

    DOEpatents

    Liu, Jian; Wan, Peng; Yang, Lihmei

    2014-07-29

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

  14. Ultrafast fiber lasers: practical applications

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  15. Fiber Laser Array

    DTIC Science & Technology

    2004-01-01

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

  16. Photonic band-gap engineering in UV fiber gratings by the arc discharge technique.

    PubMed

    Cusano, Andrea; Iadicicco, Agostino; Paladino, Domenico; Campopiano, Stefania; Cutolo, Antonello

    2008-09-29

    Localized heat treatments combined with local non-adiabatic tapering is proposed as suitable tool for the engineering of photonic band-gaps in UV-written fiber Bragg gratings (FBGs). In particular, here, we propose the use of the electric arc discharge to achieve localized defects along the FBG structure, however differently from previously reported works, we demonstrate how this post processing tool properly modified can be exploited to achieve the full control of the spectral characteristics of the final device. Also, we show how the suitable choice of the grating features and the correct selection of the defect geometry can be efficiently used to achieve interesting features for both communication and sensing applications.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Diode Pumped Fiber Laser.

    DTIC Science & Technology

    1984-12-01

    72 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 2. Mechanical Q-Switching ..................... 72 3...nonuniform heating of the molten zone due to the manner in which the laser beams are inc ident upon the source rod, and (3) mechanical vibrations in the motor...were attached to a solid block of aluminum for better mechanical stability. Curved mirrors (R = 10 cm) were obtained from an outside manufacturer for

  3. Developing Pulsed Fiber Lasers

    DTIC Science & Technology

    2007-06-15

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

  4. Continuously tunable devices based on electrical control of dual-frequency liquid crystal filled photonic bandgap fibers.

    PubMed

    Scolari, Lara; Alkeskjold, Thomas; Riishede, Jesper; Bjarklev, Anders; Hermann, David; Anawati, Anawati; Nielsen, Martin; Bassi, Paolo

    2005-09-19

    We present an electrically controlled photonic bandgap fiber device obtained by infiltrating the air holes of a photonic crystal fiber (PCF) with a dual-frequency liquid crystal (LC) with pre-tilted molecules. Compared to previously demonstrated devices of this kind, the main new feature of this one is its continuous tunability due to the fact that the used LC does not exhibit reverse tilt domain defects and threshold effects. Furthermore, the dual-frequency features of the LC enables electrical control of the spectral position of the bandgaps towards both shorter and longer wavelengths in the same device. We investigate the dynamics of this device and demonstrate a birefringence controller based on this principle.

  5. 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.

  6. Cladded single crystal fibers for high power fiber lasers

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  7. 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.

  8. 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.

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

    PubMed

    Zhang, Xiao; Song, Yanrong

    2014-05-10

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

  10. Comparison of Above Bandgap Laser and MeV Ion Induced Single Event Transients in High-Speed Si Photonic Devices

    NASA Technical Reports Server (NTRS)

    Laird, Jamie S.; Hirao, Toshio; Onoda, Shinobu; Itoh, Hisayoshi; Edmonds, Larry; Johnston, Allan

    2006-01-01

    We illustrate inherent differences between Single Event Transients generated by an above bandgap picosecond lasers and MeV heavy ions by comparing transient currents collected with an ion microbeam and picosecond laser with varying track waist.

  11. 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

  12. Advanced fiber lasers and related all-fiber devices

    NASA Astrophysics Data System (ADS)

    Srinivasan, Balaji

    2000-11-01

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

  13. 2-μm fiber laser sources for sensing

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Geng, Jihong; Jiang, Shibin

    2014-06-01

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

  14. Fiber optic applications for laser polarized targets

    SciTech Connect

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

    1997-10-01

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

  15. Nanosecond laser damage of optical multimode fibers

    NASA Astrophysics Data System (ADS)

    Mann, Guido; Krüger, Jörg

    2016-07-01

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

  16. Microring embedded hollow polymer fiber laser

    SciTech Connect

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

    2015-03-30

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

  17. 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).

  18. Advances in drilling with fiber lasers

    NASA Astrophysics Data System (ADS)

    Naeem, Mohammed

    2015-07-01

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

  19. Temperature sensing using the bandgap-like effect in a selectively liquid-filled photonic crystal fiber.

    PubMed

    Peng, Yang; Hou, Jing; Zhang, Yang; Huang, Zhihe; Xiao, Rui; Lu, Qisheng

    2013-02-01

    A compact temperature sensor based on a selectively liquid-filled photonic crystal fiber (PCF) is proposed using controlled hole collapse in PCF post-processing. The first ring around the core is filled with liquid of higher refractive index than the matrix, while the outer rings of holes are filled with air. The bandgap (BG)-like effect of the high refractive index ring is analyzed. Absorption loss spectra of the fiber are found to be quite sensitive to the refractive index of liquid when the liquid is lossy. Using the BG-like effect, a fiber temperature sensor is fabricated by selectively injecting a mixture of dimethyl sulfoxide and aqueous gold colloids with a high thermo-optic coefficient to the PCF. Temperature sensitivity up to -5.5 nm/°C is experimentally confirmed.

  20. Diode pumped alkali vapor fiber laser

    DOEpatents

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

    2006-07-26

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

  1. 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.

  2. Dark pulse emission of a fiber laser

    SciTech Connect

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

    2009-10-15

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

  3. Internal modulation of a random fiber laser.

    PubMed

    Bravo, M; Fernandez-Vallejo, M; Lopez-Amo, M

    2013-05-01

    A characterization of a modulated random mirror laser has been experimentally carried out. Unlike conventional internally modulated fiber lasers, no distortion of the modulating frequency or self-mode-locking effects were measured. The behavior of the laser using pulsed and analog modulation up to 12 GHz is shown.

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

    PubMed

    Wang, Zheng; Chocat, Noémie

    2010-06-01

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

  5. Mobile fiber-optic laser Doppler anemometer.

    PubMed

    Stieglmeier, M; Tropea, C

    1992-07-20

    A laser Doppler anemometer (LDA) has been developed that combines the compactness and low power consumption of laser diodes and avalanche photodiodes with the flexibility and possibility of miniaturization by using fiber-optic probes. The system has been named DFLDA for laser diode fiber LDA and is especially suited for mobile applications, for example, in trains, airplanes, or automobiles. Optimization considerations of fiber-optic probes are put forward and several probe examples are described in detail. Measurement results from three typical applications are given to illustrate the use of the DFLDA. Finally, a number of future configurations of the DFLDA concept are discussed.

  6. Fiber laser performance in industrial applications

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  7. Mid-Infrared Fiber Lasers (Les fibres laser infrarouge moyen)

    DTIC Science & Technology

    2010-09-01

    à fibres sont intrinsèquement mieux adaptés à ces applications que les lasers à l’état solide conventionnels, offrant un confinement optique , une...Sep 2010 Mid-Infrared Fiber Lasers (Les fibres laser infrarouge moyen) Research and Technology Organisation (NATO) BP 25, F-92201 Neuilly-sur-Seine...SET-171)TP/370 www.rto.nato.int RTO MEETING PROCEEDINGS MP-SET-171 Mid-Infrared Fiber Lasers (Les fibres laser infrarouge moyen) Papers presented

  8. Investigation of Microstructured Optical Fiber in Eight Fiber Laser

    NASA Astrophysics Data System (ADS)

    Bahloul, Faouzi; Ennejah, Tarek; Attia, Rabah

    2012-06-01

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

  9. Investigation of Microstructured Optical Fiber in Eight Fiber Laser

    NASA Astrophysics Data System (ADS)

    Bahloul, Faouzi; Ennejah, Tarek; Attia, Rabah

    2011-09-01

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

  10. Progress in Cherenkov femtosecond fiber lasers

    PubMed Central

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

    2016-01-01

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

  11. 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.

  12. Progress in Cherenkov femtosecond fiber lasers.

    PubMed

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

    2016-01-20

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

  13. Fiber laser for high speed laser transfer printing

    NASA Astrophysics Data System (ADS)

    Petkovšek, Rok; Novak, Vid; Agrež, Vid

    2017-01-01

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

  14. Review of long period fiber gratings written by CO2 laser

    NASA Astrophysics Data System (ADS)

    Wang, Yiping

    2010-10-01

    This paper presents a systematic review of long period fiber gratings (LPFGs) written by the CO2 laser irradiation technique. First, various fabrication techniques based on CO2 laser irradiations are demonstrated to write LPFGs in different types of optical fibers such as conventional glass fibers, solid-core photonic crystal fibers, and air-core photonic bandgap fibers. Second, possible mechanisms, e.g., residual stress relaxation, glass structure changes, and physical deformation, of refractive index modulations in the CO2 -laser-induced LPFGs are analyzed. Third, asymmetrical mode coupling, resulting from single-side laser irradiation, is discussed to understand unique optical properties of the CO2 -laser-induced LPFGs. Fourthly, several pretreament and post-treatment techniques are proposed to enhance the efficiency of grating fabrications. Fifthly, sensing applications of the CO2 -laser-induced LPFGs are investigated to develop various LPFG-based temperature, strain, bend, torsion, pressure, and biochemical sensors. Finally, communication applications of the CO2 -laser-induced LPFGs are investigated to develop various LPFG-based band-rejection filters, gain equalizers, polarizers, and couplers.

  15. 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.

  16. 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.

  17. 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.

  18. Wideband ultrafast fiber laser sources for OCT and metrology

    NASA Astrophysics Data System (ADS)

    Nishizawa, Norihiko

    2016-09-01

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

  19. 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.

  20. Frequency Doubling In Raman Fiber Lasers

    DTIC Science & Technology

    2009-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    PubMed

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

    2014-04-01

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

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  6. Micro-channels machined in microstructured optical fibers by femtosecond laser.

    PubMed

    van Brakel, Adriaan; Grivas, Christos; Petrovich, Marco N; Richardson, David J

    2007-07-09

    Micro-channels were fabricated in hollow-core photonic bandgap fiber (HC-PBGF) and suspended-core holey fiber (SC-HF) by femtosecond Ti:sapphire laser irradiation. Gaseous access was demonstrated via these engineered ports to the core of HC-PBGF and the hollow cladding of SC-HF. Femtosecond laser micro-machining caused no additional transmission loss in HC-PBGFs. This allowed a novel gas cell to be produced, in which gaseous access was provided solely through two micro-channels. Acetylene diffusion was also confirmed through a micro-channel leading to a single cladding airhole in SC-HF. This further highlighted the fabrication technique's precision, selectivity, and potential for developing fiber-based micro-fluidic devices.

  7. 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.

  8. 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

  9. 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.

  10. 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).

  11. Technology and applications of ultrafast fiber lasers

    NASA Astrophysics Data System (ADS)

    Lang, Marion; Hellerer, Thomas; Stuhler, Juergen

    2011-11-01

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

  12. Next Generation Large Mode Area Fiber Technologies for High Power Fiber Laser Arrays

    DTIC Science & Technology

    2012-06-08

    REPORT Next Generation Large Mode Area Fiber Technologies for High Power Fiber Laser Arrays 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: This program...monolithically-integrated building blocks (individual laser channels) of high power beam-combined fiber laser arrays. Robust single-mode performance...of CCC fibers with core sizes of up to ~60?m has been rigorously demonstrated. Various CCC fiber based high power lasers have been also

  13. Ceramic bracket debonding with ytterbium fiber laser.

    PubMed

    Sarp, Ayşe Sena Kabaş; Gülsoy, Murat

    2011-09-01

    Since the early 1990 s, lasers have been used experimentally for debonding ceramic brackets. Lasers reduce the required debonding force and risk of enamel damage. However, the thermal effect during the laser radiation on dental tissues can cause undesirable results. The aim of this study is to develop a laser debonding technique for ceramic brackets that is better than mechanical debonding and also to minimize the side-effects of laser applications. A new fiber laser (1,070-nm ytterbium fiber laser) was tested, debonding procedure was quantified with a universal testing machine, and intrapulpal temperature was monitored for limiting the injury or pain. Experiments were performed in two sections according to the type of lasing mode: continuous wave (CW) and modulated mode. In continuous wave (CW) mode, a laser was applied on samples with different constant power levels continuously. In the second set of experiments, brackets were irradiated in modulated mode, in which the laser energy was delivered with on-and-off cycles. Laser power and duty cycles were adjusted by controlling the current, which was set to 4.99 A of current for 18 W of emission. Debonding force, debonding time, and work done by a universal testing machine were all significantly decreased for both modalities of laser irradiation compared to the control group. When laser parameters were set to proper doses, a 50% of reduction in required load for debonding and a three-fold decrease in debonding time were observed. Intrapulpal temperature changes were below the accepted threshold value (5.5°C) until the level of 3.5 W of laser power in continuous wave mode. During debonding, the work done by the universal testing machine is decreased up to five times by irradiation. Parameters were compared for both modes of operations and it was concluded that modulated mode laser application (Group 300/900) provided faster and easier debonding with less temperature change.

  14. 100 W all fiber picosecond MOPA laser.

    PubMed

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

    2009-12-21

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

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

    PubMed

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

    2012-10-10

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

  16. Full-vectorial coupled mode theory for the evaluation of macro-bending loss in multimode fibers. application to the hollow-core photonic bandgap fibers.

    PubMed

    Skorobogatiy, Maksim; Saitoh, Kunimasa; Koshiba, Masanori

    2008-09-15

    In the hollow core photonic bandgap fibers, modal losses are strongly differentiated, potentially enabling effectively single mode guidance. However, in the presence of macro-bending, due to mode coupling, power in the low-loss mode launched into a bend is partially transferred into the modes with higher losses, thus resulting in increased propagation loss, and degradation of the beam quality. We show that coupled mode theory formulated in the curvilinear coordinates associated with a bend can describe correctly both the bending induced loss and beam degradation. Suggested approach works both in absorption dominated regime in which fiber modes are square integrable over the fiber crossection, as well as in radiation dominated regime in which leaky modes are not square integrable. It is important to stress that for multimode fibers, full-vectorial coupled mode theory developed in this work is not a simple approximation, but it is on par with such "exact" numerical approaches as finite element and finite difference methods for prediction of macro-bending induced losses.

  17. 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.

  18. Robust synchronization in fiber laser arrays.

    PubMed

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

    2006-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  20. Hybrid fiber-rod laser

    DOEpatents

    Beach, Raymond J.; Dawson, Jay W.; Messerly, Michael J.; Barty, Christopher P. J.

    2012-12-18

    Single, or near single transverse mode waveguide definition is produced using a single homogeneous medium to transport both the pump excitation light and generated laser light. By properly configuring the pump deposition and resulting thermal power generation in the waveguide device, a thermal focusing power is established that supports perturbation-stable guided wave propagation of an appropriately configured single or near single transverse mode laser beam and/or laser pulse.

  1. 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.

  2. Excess carrier generation in femtosecond-laser processed sulfur doped silicon by means of sub-bandgap illumination

    SciTech Connect

    Guenther, Kay-Michael; Gimpel, Thomas; Ruibys, Augustinas; Kontermann, Stefan; Tomm, Jens W.; Winter, Stefan; Schade, Wolfgang

    2014-01-27

    With Fourier-transform photocurrent spectroscopy and spectral response measurements, we show that silicon doped with sulfur by femtosecond laser irradiation generates excess carriers, when illuminated with infrared light above 1100 nm. Three distinct sub-bandgap photocurrent features are observed. Their onset energies are in good agreement with the known sulfur levels S{sup +}, S{sup 0}, and S{sub 2}{sup 0}. The excess carriers are separated by a pn-junction to form a significant photocurrent. Therefore, this material likely demonstrates the impurity band photovoltaic effect.

  3. Simultaneous temperature and force measurement using Fabry-Perot interferometer and bandgap effect of a fluid-filled photonic crystal fiber.

    PubMed

    Han, Tingting; Liu, Yan-Ge; Wang, Zhi; Wu, Zhifang; Wang, Shuangxia; Li, Shuo

    2012-06-04

    A novel fiber sensor capable of simultaneously measuring force and temperature is proposed and investigated. A section of high-index-fluid-filled photonic bandgap fiber (HIFF-PBGF) is inserted in a fiber loop to act as the sensing head. Photonic bandgap effect of the HIFF-PBGF as well as Fabry-Perot interferometer (FPI) introduced by controlling the splicing between the HIFF-PBGF and single mode fiber is used for achieving force and temperature discrimination. Taking advantage of the bandgap being high sensitivity to the temperature, a high temperature sensitivity of more than -1.94 dB/°C is achieved, which is the highest based on the intensity measurement, to our best knowledge. Meanwhile, a force sensitivity of 3.25 nm/N (~3.9 pm/με) is obtained, which could be enhanced by controlling the FPI shape. The device also has the strong points of easy fabrication, compact structure and high interference fringe contrast.

  4. 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

  5. Hybrid Fiber-Bulk Pulsed Erbium Laser

    DTIC Science & Technology

    2007-11-02

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

  6. Fiber ring laser with a feedback mirror.

    PubMed

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

    2005-12-20

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

  7. Reverse spontaneous laser line sweeping in ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

  8. 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.

  9. Wavelength-codified fiber laser hydrogen detector

    NASA Astrophysics Data System (ADS)

    Ortigosa-Blanch, A.; Díez, A.; González-Segura, A.; Cruz, J. L.; Andrés, M. V.

    2005-11-01

    We report a scheme for an optical hydrogen detector that codifies the information in wavelength. The system is based on an erbium-doped fiber laser with two coupled cavities and a Palladium-coated tapered fiber within one of the laser cavities. The tapered fiber acts as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses. This change leads the system to switch lasing from the wavelength of the auxiliary cavity to the characteristic wavelength of the cavity which contains the sensing element. The detection level can be shifted by adjusting the reflective elements of the cavity containing the sensing element.

  10. Powerful narrow linewidth random fiber laser

    NASA Astrophysics Data System (ADS)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2016-11-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  11. Powerful narrow linewidth random fiber laser

    NASA Astrophysics Data System (ADS)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2017-03-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  12. Transverse modes switchable fiber laser based on few-mode fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Sun, Biao; Wang, Anting; Zhou, Yong; Gu, Chun; Lin, Zhongxi; Xu, Lixin; Ming, Hai

    2012-11-01

    Based on the few-mode fiber Bragg grating's reflection characteristics, we propose and demonstrate a transverse modes switchable fiber laser fiber laser, fundamental mode and 1st higher order modes, and the states be switched by tuning the laser's oscillating wavelength. The radial vector beam is also obtained by splitting the degenerated 1st higher order modes.

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

    PubMed

    Gan, Zongsong; Cao, Yaoyu; Gu, Min

    2013-05-06

    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.

  14. 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.

  15. 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.

  16. Nonlinear High-Energy Pulse Propagation in Graded-Index Multimode Optical Fibers for Mode-Locked Fiber Lasers

    DTIC Science & Technology

    2014-12-23

    High-Energy Pulse Propagation in Graded -Index Multimode Optical Fibers for Mode-Locked Fiber Lasers 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-12-1...integration of large-core graded -index multimode fibers (GIMFs) in ultrafast mode-locked fiber lasers to dramatically increase the pulse energy...optical fibers, graded -index multimode fibers, nonlinear switching, waveguides, mode-locked fiber lasers, ultra-short pulse fiber lasers 16. SECURITY

  17. Performance analysis of CO2 laser polished angled ribbon fiber

    NASA Astrophysics Data System (ADS)

    Sohn, Ik-Bu; Choi, Hun-Kook; Noh, Young-Chul; Lee, Man-Seop; Oh, Jin-Kyoung; Kim, Seong-min; Ahsan, Md. Shamim

    2017-01-01

    This paper demonstrates CO2 laser assisted simultaneous polishing of angled ribbon fibers consisting eight set of optical fibers. The ribbon fibers were rotated vertically at an angle of 12° and polished by repetitive irradiation of CO2 laser beam at the end faces of the fibers. Compared to mechanically polished sharp edged angled fibers, CO2 laser polishing forms curve edged angled fibers. Increase in the curvature of the end faces of the ribbon fibers causes the increase of the fibers' strength, which in turn represents great robustness against fiber connections with other devices. The CO2 laser polished angled fibers have great smoothness throughout the polished area. The smoothness of the fiber end faces have been controlled by varying the number of laser irradiation. After CO2 laser polishing, the average value of the fiber angle of the ribbon fibers is ∼8.28°. The laser polished ribbon fibers show low insertion and return losses when connecting with commercial optical communication devices. The proposed technique of polishing the angled ribbon fibers is highly replicable and reliable and thus suitable for commercial applications.

  18. All-fiber passively mode-locked Ho-laser pumped by ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Filatova, S. A.; Kamynin, V. A.; Zhluktova, I. V.; Trikshev, A. I.; Tsvetkov, V. B.

    2016-11-01

    We report an all-fiber mode-lock holmium-doped ring laser passively mode-locked by nonlinear polarization rotation without dispersion compensation. The laser produced picosecond pulses at 2.057 µm. The average output power was 4.5 mW.

  19. Lateral band-gap control of InGaAsP multiple quantum wells by laser-assisted metalorganic molecular beam epitaxy for a multiwavelength laser array

    NASA Astrophysics Data System (ADS)

    Iga, Ryuzo; Yamada, Takeshi; Sugiura, Hideo

    1994-02-01

    Multiple asymmetric quantum wells made up of InGaAsP and InAsP layers were fabricated using laser irradiation. They were formed in different irradiated areas during InGaAsP quantum well growth by Ar-ion laser assisted metalorganic molecular beam epitaxy (MOMBE). It was observed that during MOMBE the band gap of InGaAsP MQW was modified. Photoluminescence wavelengths of the MAQWs were studied to observe the variations in the bandgap with a delay in the starting time of laser irradiation. The photoluminescence of the MAQWs ranged from 1.3 to 1.5 micrometer and the PL intensity of the MAQWs in four different areas were all similar. This phenomena enabled the fabrication of multiwavelength laser array on a substrate in a single step growth.

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

    PubMed Central

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

    2016-01-01

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

  1. 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.

  2. 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

  3. 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.

  4. Multi-watt 589nm fiber laser source

    NASA Astrophysics Data System (ADS)

    Dawson, Jay W.; Drobshoff, Alex D.; Beach, Raymond J.; Messerly, Michael J.; Payne, Stephen A.; Brown, Aaron; Pennington, Deanna M.; Bamford, Douglas J.; Sharpe, Scott J.; Cook, David J.

    2006-02-01

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichio-metric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd 3+ fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the 1088nm 4-level laser transition. At 15W, the 938nm laser has an M2 of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss the fiber laser design and operation as well as our results in power scaling at 589nm.

  5. 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.

  6. Design of single-polarization coupler based on dual-core photonic band-gap fiber implied in resonant fiber optic gyro

    NASA Astrophysics Data System (ADS)

    Xu, Zhenlong; Li, Xuyou; Zhang, Chunmei; Ling, Weiwei; Liu, Pan; Xia, Linlin; Yang, Hanrui

    2016-12-01

    A novel (to our knowledge) type of single-polarization (SP) coupler based on a dual-core photonic band-gap fiber (PBF) is proposed. The effects of structure parameters on the performance of this coupler are studied numerically based on the full vector finite element method (FEM). Finally, an optimal design with a length of 0.377 mm at the wavelength of 1.55 μm is achieved, and its implication in PBF-based fiber ring resonator (FRR), the effect of angular misalignment on the SP coupler are analyzed as well. When the SP coupler is incorporated into a PBF-based FRR, it functions as the power splitter and the polarizer simultaneously, and can extinct the secondary eigenstate of polarization (ESOP) propagating in the FRR. The mode field of SP coupler can match with the polarization-maintaining (PM) PBF with ultra-low temperature sensitivity proposed in previous study, and an all PM-PBF based FRR can be established, which is of great significance in suppressing the temperature-related polarization fluctuation and improving the long-term stability for RFOG, and the SP coupler has high angular misalignment tolerance as well.

  7. 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.

  8. Laser and Optical Fiber Metrology in Romania

    SciTech Connect

    Sporea, Dan; Sporea, Adelina

    2008-04-15

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

  9. Laser and Optical Fiber Metrology in Romania

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Sporea, Adelina

    2008-04-01

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

  10. 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.

  11. 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.

  12. 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.

  13. Pressure-gradient fiber laser hydrophone

    NASA Astrophysics Data System (ADS)

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

    2009-10-01

    A pressure-gradient fiber laser hydrophone (FLH) is demonstrated. Two brass diaphragms are installed at the end of a metal cylinder as the sensing element. There are two orifices at the middle of the cylinder. This structure can work as a pressure-gradient microphone in the acoustic field. Thus the DFB fiber laser fixed at the center of the two diaphragms is elongated or shortened due to the acoustic wave. Theoretical analysis is given based on the electro-acoustic theory. Experiments are carried out to test the performance of the hydrophone. A sensitivity of 100 nm/MPa has been achieved. Furthermore, the hydrostatic pressure is self-compensated and a ultra-thin dimension is achieved based on the proposed structure.

  14. Self-Centering of a Ball Lens by Laser Trapping: Fiber-Ball-Fiber Coupling Analysis

    NASA Astrophysics Data System (ADS)

    Gauthier, Robert C.; Friesen, Michael; Gerrard, Thomas; Hassouneh, Wissam; Koziorowski, Piotr; Moore, Damian; Oprea, Karen; Uttamalingam, Sivasanker

    2003-03-01

    Fiber-to-fiber coupling through use of a laser-trapped microball lens is examined. A model based on radiation pressure predicts that the ball lens will align axially between the fiber endfaces. Laser manipulation of the ball lens axial position results in a configuration in which the ball lens optically bridges the gap between the fibers. Experimental results are presented for several fiber endface separations, and it is found that the presence of the microball lens can increase the coupling by a factor of 2 above the level expected by direct fiber-to-fiber coupling for the same fiber endface separation.

  15. Germanate Glass Fiber Lasers for High Power

    DTIC Science & Technology

    2016-01-04

    germanate based glasses with a specific focus on glass stability during thermal- cycling which is representative of the steps required to fabricate a doped...evidence of crystallisation after thermal cycling , and is of a low enough loss to realize a fiber laser. The glass stability is demonstrated by...specific focus on glass stability during thermal- cycling which is representative of the steps required to fabricate a doped micro-structured germanate

  16. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  18. 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.

  19. AlInGaN Bandgap and Doping Engineering for Visible Laser

    DTIC Science & Technology

    2012-02-08

    chip-scale visible lasers for many applications, including laser sight, environmental monitoring, and compact pumping sources for ultra-short laser...and compact pumping sources for ultra-short laser pulse generation, high luminous full color displays, new generation solid-state lighting, etc. The...monitoring, and compact pumping sources for ultra-short laser pulse generation, high luminous full color displays, new generation solid-state

  20. 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.

  1. Comparison of core fibers and contact probes for laser surgery

    NASA Astrophysics Data System (ADS)

    Steiner, Rudolf W.; Keckstein, J.; Finger, Anthonio

    1990-07-01

    Advanced laser operational techniques have been introduced using the Nd:YAG or the argon laser in combination with fiber techniques and contact probes . In gynaecology, for exantple, surgeons need highly flexible fiber transmission systems for laparoscopic operations 2 Indications such as adhesiolysis or endornetriosis can be treated without mechanical traumatisation and bleeding using the laser light. Laser systems with different wavelengths, fibers and tips have become a very flexible surgical instrument. Feedback control of the reaction of the laser light with tissue makes the inedical laser system save and reliable.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  3. 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.

  4. Comparative study of ring and random cavities for fiber lasers.

    PubMed

    Fernandez-Vallejo, Montserrat; Rota-Rodrigo, Sergio; Lopez-Amo, Manuel

    2014-06-01

    An experimental comparison of three fiber laser structures with the same Raman gain medium is presented in order to establish the main pros and cons of each basic scheme. The first fiber laser is based on a hybrid ring-random fiber laser, the second one is a pure ring fiber laser, and the last one is a random fiber laser. Several aspects have been taken into account in the study. First, from the optical point of view, the parameters of interest compared are output power, lasing threshold, slope efficiency, power fluctuations, and the longitudinal modes have been analyzed. Second, the possible utilization of fiber lasers in digital modulated optical communication systems is also studied.

  5. 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.

  6. Thulium-doped all-fiber mode-locked laser synchronously pumping by a fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Gen; Hu, Yangyang; Yan, Ke; Zhang, Chun; Zhang, Junyi; Gu, Chun; Xu, Lixin

    2016-09-01

    We demonstrate a thulium-doped all fiber actively mode-locked laser by synchronously pumping without electronic modulator. A mode-locked fiber laser operating at 1550 nm based on nonlinear polarization rotation (NPR) is innovatively utilized as the pulsed pump. Through cavity length matching, stable mode-locking that operate at 1891.25 nm is achieved with a spectral width of 0.52 nm at 3 dB. The repetition rate is 11.59 MHz with an estimated pulse duration less than 125 ps.

  7. Photodegradation of fluoride glass blue fiber laser

    NASA Astrophysics Data System (ADS)

    Chandonnet, Alain; Laperle, Pierre; LaRochelle, Sophie; Vallee, Real

    1997-01-01

    The first demonstration of blue upconversion fiber lasers in Tm-ZBLAN has generated considerable interest among laser scientists looking for all-solid-state visible sources. Although initial experiments have shown a large conversion efficiency, a good spatial beam quality and an overall simplicity of the approach, these sources have not yet appeared on the market. In an attempt to reproduce these early results, many research teams including our own have encountered unexplained and detrimental start-up effects in these lasers. We have recently shown that this behavior is the result of photochromic damage in the fluoride fibers generated by the infrared pumping source. Progressive build- up of photoinduced loss ultimately prevents operation of the device. The photoinduced absorption spectrum extends from the UV to the near infrared, with three major bands centered around 300 nm, 500 nm and 800 nm. Pump-probe experiments show that the damage mechanism depends on the Tm3+ concentration and that it follows a fourth power dependence on the pumping intensity. Further investigation has revealed that photobleaching of the defects is possible using visible and near infrared radiation. The residual absorption spectrum following photobleaching suggests that three different species of defects are created. One type of defects is related to the 800 nm band and can be permanently removed. The other two are only temporarily removed by photobleaching and reappear on a time-scale of a few minutes. In addition, thermal bleaching can completely erase the defects in certain fibers. This paper summarizes the current understanding of photoinduced phenomena occurring in Tm3+-ZBLAN fibers.

  8. High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-01

    demonstrated in a moder- ately turbulent environment. HIgH-PowEr FIbEr LAsErs Although a number of companies manufacture high-power fiber lasers , IPG ...in approximately one year. Multi- kilowatt , single-mode fiber lasers are robust, compact, and have high wall- plug efficiency, random polarization...and large band- width (~0.1%). A 1 kW, single-mode IPG fiber laser module, operating at wavelength l = 1.075 μm, exclud- ing power supply, measures w

  9. 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

  10. 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

  11. Advances in fiber laser spectral beam combining for power scaling

    NASA Astrophysics Data System (ADS)

    Honea, Eric; Afzal, Robert S.; Savage-Leuchs, Matthias; Henrie, Jason; Brar, Khush; Kurz, Nathan; Jander, Don; Gitkind, Neil; Hu, Dan; Robin, Craig; Jones, Andrew M.; Kasinadhuni, Ravi; Humphreys, Richard

    2016-03-01

    Spectral Beam Combining (SBC) of fiber lasers provides a simple, robust architecture for high brightness power scaling beyond the limit of a single fiber. We review recent progress in power scaling and describe what we believe is the highest power SBC fiber demonstration and largest number of fiber lasers combined to date. Here we report results on a fiber SBC system where we achieved > 30 kW by combining 96 individual fiber lasers into a single high brightness beam with a beam quality of M2 = 1.6 x 1.8. The potential for further power scaling at the system level is highlighted with examples of beam combinable fiber laser power scaling.

  12. Plasticity of climbing fibers after laser axotomy

    NASA Astrophysics Data System (ADS)

    Allegra Mascaro, A. L.; Cesare, P.; Sacconi, L.; Grasselli, G.; Strata, P.; Pavone, F. S.

    2010-02-01

    In the adult nervous system, different population of neurons corresponds to different regenerative behavior. Although previous works show that olivocerebellar fibers are capable of axonal regeneration in a suitable environment as a response to injury1, we have hitherto no details about the real dynamics of fiber regeneration. We coupled two photon imaging to laser-induced lesions to perform in vivo multiphoton nanosurgery in the CNS of living mice expressing fluorescent proteins to investigate the reparative properties of Climbing Fibers (CFs) in the adult CNS, following the time evolution of this plastic process in vivo. Here we show that a regenerative event may take place in a murine model in the days that follow a sub-micrometric lesion on the distal portion of the climbing fiber. Furthermore this unique model could allow, through manipulation of the viral vector, to explore in detail the biochemical mechanisms underlying the reparative process. The great potential of long-term two photon imaging, coupled to genetic manipulation, opens great opportunities to further investigate the dynamic properties of neurons and their rearrangement following an injury.

  13. 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.

  14. 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.

  15. 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.

  16. 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).

  17. 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

  18. Numerical modeling of mode-locked fiber lasers with a fiber-based saturable-absorber

    NASA Astrophysics Data System (ADS)

    Wang, Long; Chong, Andy; Haus, Joseph W.

    2017-01-01

    We report fiber laser simulations with a fiber compatible, self-focusing, saturable absorber (SA) device. The SA device consists of two tapered fiber ends separated by a bulk, nonlinear medium. An optical beam transmitted from one tapered fiber end, propagate through the nonlinear medium (chalcogenide glass As40 S e60) and couples back into the other tapered fiber end. Pulse propagation in the fiber laser cavity is performed using the Split Step Method. Stable pulses are generated with energies around 0.3 nJ and a transform limited pulse width around 200 fs.

  19. 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.

  20. Novel high-brightness fiber coupled diode laser device

    NASA Astrophysics Data System (ADS)

    Haag, Matthias; Köhler, Bernd; Biesenbach, Jens; Brand, Thomas

    2007-02-01

    High brightness becomes more and more important in diode laser applications for fiber laser pumping and materials processing. For OEM customers fiber coupled devices have great advantages over direct beam modules: the fiber exit is a standardized interface, beam guiding is easy with nearly unlimited flexibility. In addition to the transport function the fiber serves as homogenizer: the beam profile of the laser radiation emitted from a fiber is symmetrical with highly repeatable beam quality and pointing stability. However, efficient fiber coupling requires an adaption of the slow-axis beam quality to the fiber requirements. Diode laser systems based on standard 10mm bars usually employ beam transformation systems to rearrange the highly asymmetrical beam of the laser bar or laser stack. These beam transformation systems (prism arrays, lens arrays, fiber bundles etc.) are expensive and become inefficient with increasing complexity. This is especially true for high power devices with small fiber diameters. On the other hand, systems based on single emitters are claimed to have good potential in cost reduction. Brightness of the inevitable fiber bundles, though, is limited due to inherent fill-factor losses. At DILAS a novel diode laser device has been developed combining the advantages of diode bars and single emitters: high brightness at high reliability with single emitter cost structure. Heart of the device is a specially tailored laser bar (T-Bar), which epitaxial and lateral structure was designed such that only standard fast- and slow-axis collimator lenses are required to couple the beam into a 200μm fiber. Up to 30 of these T-Bars of one wavelength can be combined to reach a total of > 500W ex fiber in the first step. Going to a power level of today's single emitter diodes even 1kW ex 200μm fiber can be expected.

  1. Packaging considerations of fiber-optic laser sources

    NASA Astrophysics Data System (ADS)

    Heikkinen, Veli; Tukkiniemi, Kari; Vaehaekangas, Jouko; Hannula, Tapio

    1991-12-01

    The continuous progress in material and component technology has generated new laser-based applications that require special packaging techniques. Hybrid integration offers a flexible method to accomplish custom design needs. This paper discusses several aspects in fiber optic packaging including optical, thermal, and mechanical issues. Special emphasis is on optical coupling between a laser diode and a single-mode fiber.

  2. Profiling atmospheric water vapor using a fiber laser lidar system.

    PubMed

    De Young, Russell J; Barnes, Norman P

    2010-02-01

    A compact, lightweight, and efficient fiber laser lidar system has been developed to measure water vapor profiles in the lower atmosphere of Earth or Mars. The line narrowed laser consist of a Tm:germanate fiber pumped by two 792 nm diode arrays. The fiber laser transmits approximately 0.5 mJ Q- switched pulses at 5 Hz and can be tuned to water vapor lines near 1.94 microm with linewidth of approximately 20 pm. A lightweight lidar receiver telescope was constructed of carbon epoxy fiber with a 30 cm Fresnel lens and an advanced HgCdTe APD detector. This system has made preliminary atmospheric measurements.

  3. 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.

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

    PubMed

    Freitag, Christian; Weber, Rudolf; Graf, Thomas

    2014-01-27

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

  5. New generation high-power rare-earth-doped phosphate glass fiber and fiber laser

    NASA Astrophysics Data System (ADS)

    Wu, Ruikun; Myers, John D.; Myers, Michael J.

    2001-04-01

    High power, high brightness fiber lasers have numerous potential commercial and military applications. Fiber lasers with cladding pump designs represent a new generation of diode pumped configurations that are extremely efficient, have single mode output and may be operated with or without active cooling. Kigre has invented a new family of Er/Yb/Nd phosphate laser glass materials (designated QX) that promise to facilitate a quantum leap in fiber laser technology of this field. The new phosphate glass Rare-Earth doped fiber exhibit many advantages than Silica or Fluoride base fiber, see table.1. Instead of 30 to 50 meters of fused silica with a 50 mm bend radii; Kigre's phosphate glass fiber amplifiers may be designed to be less than 4 meters long .Laser performance and various design parameters, such as the fiber core diameter, NA, inner cladding shape and doping concentration are evaluated. Laser performances was demonstrated for an experimental QX/Er doubled clading fiber commissioned by MIT having 8 micron core, a 240 X 300 micron rectangle shaped inner cladding with 0.4 NA and 500 micron outer clading.. Kigre obtained approximately 2 dB/cm gain from 15cm long fiber under 940nm pumping The same fiber was evaluated by researcher at MIT. They used 975nm pump source. Maximum 270mW output was demonstrated by 30 cm long fiber with Fresnel reflection resonator mirrors. The slope efficiency of absorbed pump power s 47%.

  6. Dye-doped cholesteric lasers: Distributed feedback and photonic bandgap lasing models

    NASA Astrophysics Data System (ADS)

    Ilchishin, Igor P.; Tikhonov, Eugene A.

    2015-05-01

    A review of authors' contributions to dye-doped cholesteric liquid crystal (CLC) lasers started from the pioneer authors' paper of 1980 in which the experimental realization of the first CLC laser is presented. Both distributed feedback (DFB) and photonics band edge lasing models are discussed for different experimental conditions. A detailed study and analysis of basic characteristics of steroidal CLC lasers with low liquid crystal optical birefringence is considered with respect to the DFB model. The manifestation of a planar texture quality and mutual orientations of directors on the substrates influencing on the lasing characteristics in steroidal CLCs have been shown and described. The reversible phototuning of the CLC laser wavelength by trans-cis transitions of photoactive components is realized. Reasons for two theoretical models' coexistence for the description of dye-doped CLC lasing is considered.

  7. High performance distributed feedback fiber laser sensor array system

    NASA Astrophysics Data System (ADS)

    He, Jun; Li, Fang; Xu, Tuanwei; Wang, Yan; Liu, Yuliang

    2009-11-01

    Distributed feedback (DFB) fiber lasers have their unique properties useful for sensing applications. This paper presents a high performance distributed feedback (DFB) fiber laser sensor array system. Four key techniques have been adopted to set up the system, including DFB fiber laser design and fabrication, interferometric wavelength shift demodulation, digital phase generated carrier (PGC) technique and dense wavelength division multiplexing (DWDM). Experimental results confirm that a high dynamic strain resolution of 305 fɛ/√Hz (@ 1 kHz) has been achieved by the proposed sensor array system. And the multiplexing of eight channel DFB fiber laser sensor array has been demonstrated. The proposed DFB fiber laser sensor array system is suitable for ultra-weak signal detection, and has potential applications in the field of petroleum seismic explorations, earthquake prediction, and security.

  8. Recent progress in chiral photonic band-gap liquid crystals for laser applications.

    PubMed

    Furumi, Seiichi

    2010-12-01

    This article describes a brief review of recent research advances in chiral liquid crystals (CLCs) for laser applications. The CLC molecules have an intrinsic capability to spontaneously organize supramolecular helical assemblages consisting of liquid crystalline layers through their helical twisting power. Such CLC supramolecular helical structures can be regarded as one-dimensional photonic crystals (PhCs). Owing to their supramolecular helical structures, the CLCs show negative birefringence along the helical axis. Selective reflection of circularly polarized light is the most unique and important optical property in order to generate internal distributed feedback effect for optically-excited laser emission. When a fluorescent dye is embedded in the CLC medium, optical excitation gives rise to stimulated laser emission peak(s) at the band edge(s) and/or within the CLC selective reflection. Furthermore, the optically-excited laser emission peaks can be controlled by external stimuli through the self-organization of CLC molecules. This review introduces the research background of CLCs carried out on the PhC realm, and highlights intriguing precedents of various CLC materials for laser applications. It would be greatly advantageous to fabricate active CLC laser devices by controlling the supramolecular helical structures. Taking account of the peculiar features, we can envisage that a wide variety of supramolecular helical structures of CLC materials will play leading roles in next-generation optoelectronic molecular devices.

  9. Explicit solution for Raman fiber laser using Lambert W function.

    PubMed

    Huang, Chaohong; Cai, Zhiping; Ye, Chenchun; Xu, Huiying

    2007-04-16

    In this paper, an approximate explicit solution for the first-order Raman fiber laser is obtained by using Lambert W function. Good agreement between the explicit solution and numerical simulation is demonstrated. Furthermore, the optimal design of Raman fiber laser is discussed using the proposed solution. The optimal values of fiber length, reflectivity of output fiber Bragg grating and power transfer efficiency are obtained under different pump power. There exists a certain tolerance of the optimal parameters, in which the output power decreases only slightly. The optimal fiber length and reflectivity of output FBG decrease with increasing pump power.

  10. Explicit solution for Raman fiber laser using Lambert W function

    NASA Astrophysics Data System (ADS)

    Huang, Chaohong; Cai, Zhiping; Ye, Chenchun; Xu, Huiying

    2007-04-01

    In this paper, an approximate explicit solution for the first-order Raman fiber laser is obtained by using Lambert W function. Good agreement between the explicit solution and numerical simulation is demonstrated. Furthermore, the optimal design of Raman fiber laser is discussed using the proposed solution. The optimal values of fiber length, reflectivity of output fiber Bragg grating and power transfer efficiency are obtained under different pump power. There exists a certain tolerance of the optimal parameters, in which the output power decreases only slightly. The optimal fiber length and reflectivity of output FBG decrease with increasing pump power.

  11. 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%.

  12. 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.

  13. A cladding-pumped, tunable holmium doped fiber laser.

    PubMed

    Simakov, Nikita; Hemming, Alexander; Clarkson, W Andrew; Haub, John; Carter, Adrian

    2013-11-18

    We present a tunable, high power cladding-pumped holmium doped fiber laser. The laser generated >15 W CW average power across a wavelength range of 2.043 - 2.171 μm, with a maximum output power of 29.7 W at 2.120 μm. The laser also produced 18.2 W when operating at 2.171 µm. To the best of our knowledge this is the highest power operation of a holmium doped laser at a wavelength >2.15 µm. We discuss the significance of background losses and fiber design for achieving efficient operation in holmium doped fibers.

  14. Output-coupling optimization of Nd-doped fiber lasers.

    PubMed

    Sanchez, F; Meziane, B; Chartier, T; Stephan, G; François, P L

    1995-11-20

    A simple theoretical modeling of the static properties of a fiber laser that includes distributed losses and inhomogeneous pumping is presented. Closed-form expressions for both the output and the backward (at the input mirror) intensities are obtained. The model is based on an extended formulation of the Rigrod's theory. It is shown that the laser responds differently depending on the length of the fiber. In particular, we show that for long (short) lasers optimal output power is achieved with low (high) output-coupler reflectivities. Experimental evidence of these results is obtained with Nd-doped fiber lasers with various lengths.

  15. 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.

  16. X-band continuously variable true-time delay lines using air-guiding photonic bandgap fibers and a broadband light source.

    PubMed

    Liu, Zhigang; Zheng, Xiaoping; Zhang, Hanyi; Guo, Yili; Zhou, Binggun

    2006-09-15

    We propose a novel implementation of true-time delay (TTD) using air-guiding photonic bandgap fibers (PBGFs) and a broadband light source. The air-guiding PBGFs are experimentally studied and used in the TTD module for the first time, to the best of our knowledge. The proposed approach shows the advantages of simple architecture, compact size, larger dispersion, low-temperature sensitivity, and high immunity to nonlinear effects in our experiments. The PBGFs were spliced with single-mode fibers with a 2 dB loss, and the characteristics of the PBGFs were measured. The PBGF-TTD with a continuously tunable time delays from 0 to 500 ps was demonstrated using the amplified spontaneous emission light of an erbium-doped filter amplifier as a broadband light source.

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

    SciTech Connect

    Messerly, M J

    2007-11-13

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

  18. Bandgap Engineering of Phosphorene by Laser Oxidation toward Functional 2D Materials.

    PubMed

    Lu, Junpeng; Wu, Jing; Carvalho, Alexandra; Ziletti, Angelo; Liu, Hongwei; Tan, Junyou; Chen, Yifan; Castro Neto, A H; Özyilmaz, Barbaros; Sow, Chorng Haur

    2015-10-27

    We demonstrate a straightforward and effective laser pruning approach to reduce multilayer black phosphorus (BP) to few-layer BP under ambient condition. Phosphorene oxides and suboxides are formed and the degree of laser-induced oxidation is controlled by the laser power. Since the band gaps of the phosphorene suboxide depend on the oxygen concentration, this simple technique is able to realize localized band gap engineering of the thin BP. Micropatterns of few-layer phosphorene suboxide flakes with unique optical and fluorescence properties are created. Remarkably, some of these suboxide flakes display long-term (up to 2 weeks) stability in ambient condition. Comparing against the optical properties predicted by first-principle calculations, we develop a "calibration" map in using focused laser power as a handle to tune the band gap of the BP suboxide flake. Moreover, the surface of the laser patterned region is altered to be sensitive to toxic gas by way of fluorescence contrast. Therefore, the multicolored display is further demonstrated as a toxic gas monitor. In addition, the BP suboxide flake is demonstrated to exhibit higher drain current modulation and mobility comparable to that of the pristine BP in the electronic application.

  19. Fabrication and bandgap engineering of doped ZnO microspheres by simple laser ablation in air

    NASA Astrophysics Data System (ADS)

    Nakamura, Daisuke; Shimogaki, Tetsuya; Tanaka, Toshinobu; Nagasaki, Fumiaki; Fujiwara, Yuki; Higashihata, Mitsuhiro; Ikenoue, Hiroshi; Okada, Tatsuo

    2016-03-01

    We synthesized magnesium (Mg)-doped ZnO microspheres by laser ablation of a ZnO sintered target containing magnesium oxide (MgO) with the fundamental of a Nd:YAG laser at 1064 nm. The well-spherical ZnO microcrystals with diameters of 1-20 μm were collected on a substrate which was put near the ablation spot. X-ray diffraction and micro-Raman spectrum indicate that the ZnO microspheres have a crystalline structure. Room-temperature photoluminescence properties of the microsphere were investigated under third harmonic generation of a Nd:YAG laser excitation at 355 nm. An ultraviolet (UV) lasing in whispering gallery mode (WGM) and blue-shift of the UV WGM peaks were observed from the Mg-doped ZnO microsphere.

  20. Gas-Filled Hollow Core Fiber Lasers Based on Population Inversion

    DTIC Science & Technology

    2013-12-05

    iodine (I2) and pumped at ~ 532 nm was studied. Toward improved fiber transmission measurements, novel thulium /holmium fiber laser near 2 microns...transmission, we have demonstrated a novel thulium /holmium fiber laser near 2 microns. Abstract (short): Hollow-core Optical Fiber Gas LASer...measurements, novel thulium /holmium fiber laser near 2 microns were created. H. Schlossberg Hollow-Core Optical Fiber Gas Lasers K. Corwin et al

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  2. Hollow steel tips for reducing distal fiber burn-back during thulium fiber laser lithotripsy.

    PubMed

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

    2013-07-01

    The use of thulium fiber laser (TFL) as a potential alternative laser lithotripter to the clinical holmium:YAG laser is being studied. The TFL's Gaussian spatial beam profile provides efficient coupling of higher laser power into smaller core fibers without proximal fiber tip degradation. Smaller fiber diameters are more desirable, because they free up space in the single working channel of the ureteroscope for increased saline irrigation rates and allow maximum ureteroscope deflection. However, distal fiber tip degradation and "burn-back" increase as fiber diameter decreases due to both excessive temperatures and mechanical stress experienced during stone ablation. To eliminate fiber tip burn-back, the distal tip of a 150-μm core silica fiber was glued inside 1-cm-long steel tubing with fiber tip recessed 100, 250, 500, 1000, or 2000 μm inside the steel tubing to create the hollow-tip fiber. TFL pulse energy of 34 mJ with 500-μs pulse duration and 150-Hz pulse rate was delivered through the hollow-tip fibers in contact with human calcium oxalate monohydrate urinary stones during ex vivo studies. Significant fiber tip burn-back and degradation was observed for bare 150-μm core-diameter fibers. However, hollow steel tip fibers experienced minimal fiber burn-back without compromising stone ablation rates. A simple, robust, compact, and inexpensive hollow fiber tip design was characterized for minimizing distal fiber burn-back during the TFL lithotripsy. Although an increase in stone retropulsion was observed, potential integration of the hollow fiber tip into a stone basket may provide rapid stone vaporization, while minimizing retropulsion.

  3. 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.

  4. Incoherent Combining of High-Power Fiber Lasers for Directed-Energy Applications

    DTIC Science & Technology

    2008-01-16

    fiber lasers , IPG Photonics currently holds the record, producing over 3 kW per fiber of single-mode laser ...energy laser systems. The first field demonstration of incoherent beam combining using kilowatt -class, single-mode fiber lasers over a kilometer...combining using kilowatt -class, single-mode fiber lasers . The experiment combined four fiber lasers using a beam director consisting of

  5. 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.

  6. 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.

  7. OSNR enhancement utilizing large effective area fiber in a multiwavelength Brillouin-Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Sonee Shargh, R.; Al-Mansoori, M. H.; Anas, S. B. A.; Sahbudin, R. K. Z.; Mahdi, M. A.

    2011-02-01

    We propose a simple Brillouin-Raman multi-channel fiber laser with supportive Rayleigh scattering in a linear cavity without employing any feedback mirrors at the end of cavity. Brillouin and the consequences of Rayleigh scattering work as virtual mirrors. We employ a section of large effective area fiber in addition to a section of dispersion compensating fiber to enhance the optical signal-to-noise ratio of multi-channel Brillouin-Raman comb fiber laser. We able to produce a flat comb fiber laser with 37 nm bandwidth from 1539 to 1576 nm built-in 460 Stokes lines with 0.08 nm spacing. Furthermore, this Brillouin-Raman comb fiber laser has acceptable optical signal-to-noise ratio value of 16.8 dB for the entire bandwidth with excellent flatness and low discrepancies in power levels of about 2.3 dB between odd and even channels.

  8. 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.

  9. OEM fiber laser rangefinder for long-distance measurement

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  10. High-resolution measurement of fiber length by using a mode-locked fiber laser configuration.

    PubMed

    Hu, Y L; Zhan, L; Zhang, Z X; Luo, S Y; Xia, Y X

    2007-06-15

    A simple method to precisely measure fiber length has been experimentally demonstrated by using a mode-locked fiber laser configuration. Since the transit time in a cavity is exactly proportional to the cavity length, it is easy to obtain the fiber length from the generation of mode-locked pulses in the fiber laser with a long-range nonlinear optical loop mirror that includes the measured fiber. Our new method has a large measurement range, over hundreds of kilometers, and a high resolution, of the order of centimeters, as well as no measurement dead zone.

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

    PubMed

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

    2015-03-11

    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.

  12. Fiber Optic Laser Delivery For Endarterectomy Of Experimental Atheromas

    NASA Astrophysics Data System (ADS)

    Eugene, John; Pollock, Marc E.; McColgan, Stephen J.; Hammer-Wilson, Marie; Berns, Michael W.

    1986-08-01

    Fiber optic delivery of argon ion laser energy and Nd-YAG laser energy were compared by the performance of open laser endarterectomy in the rabbit arteriosclerosis model. In Group I, 6 open laser endarterectomies were performed with an argon ion laser (488 nm and 514.5 nm) with the laser beam directed through a 400 pm quartz fiber optic. In Group II, 6 open laser endarterectomies were performed with a Nd-YAG laser (1.06 pm) with the laser beam directed through a 600 pm quartz fiber optic. Gross and light microscopic examination revealed smooth endarterectomy surfaces with tapered end points in Group I. In Group II, the endarterectomy surfaces were uneven and perforation occurred at 5/6 end points. Although energy could be precisely delivered with each laser by fiber optics, satisfactory results could only be achieved with the argon ion laser because argon ion energy was well absorbed by atheromas. Successful intravascular laser use requires a strong interaction between wavelength and atheroma as well as a precise delivery system.

  13. Enhanced characteristics of fused silica fibers using laser polishing

    NASA Astrophysics Data System (ADS)

    Heptonstall, A.; Barton, M. A.; Bell, A. S.; Bohn, A.; Cagnoli, G.; Cumming, A.; Grant, A.; Gustafson, E.; Hammond, G. D.; Hough, J.; Jones, R.; Kumar, R.; Lee, K.; Martin, I. W.; Robertson, N. A.; Rowan, S.; Strain, K. A.; Tokmakov, K. V.

    2014-05-01

    The search for gravitational wave signals from astrophysical sources has led to the current work to upgrade the two largest of the long-baseline laser interferometers, the LIGO detectors. The first fused silica mirror suspensions for the Advanced LIGO gravitational wave detectors have been installed at the LIGO Hanford and Livingston sites. These quadruple pendulums use synthetic fused silica fibers produced using a CO2 laser pulling machine to reduce thermal noise in the final suspension stage. The suspension thermal noise in Advanced LIGO is predicted to be limited by internal damping in the surface layer of the fibers, damping in the weld regions, and the strength of the fibers. We present here a new method for increasing the fracture strength of fused silica fibers by laser polishing of the stock material from which they are produced. We also show measurements of mechanical loss in laser polished fibers, showing a reduction of 30% in internal damping in the surface layer.

  14. 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.

  15. Characterization of novel optical fibers for use in laser detonators

    NASA Astrophysics Data System (ADS)

    Bowden, M. D.; Drake, R. C.; Singleton, C. A.

    2006-08-01

    A system for launching flyers using a Q-switched Nd: YAG laser has been developed for shock initiation of secondary explosives. Flyers have been launched at velocities approaching 6 km s -1. Optical fibers are used to transport the optical energy from the laser to the detonator. The launch of these flyers with sufficient velocity requires a fluence in the region of 35 J cm -2, significantly above the damage threshold of most optical fibers. This damage is typically caused by laser absorption at the input face due to imperfections in the surface polishing. A variety of optical fibers with high quality input faces have been tested at fluences up to 50 J cm -2, and their damage thresholds and beam profiles have been measured. The standard fiber used in this system is a low hydroxyl (-OH) content, 400μm diameter core silica fiber, with CO2 laser polished faces. In addition to this, fibers tapering down to 300μm and 200μm core diameter were investigated, as a means of increasing the efficiency of the system, along with mechanically polished fibers. The fiber currently enters the detonator body from the rear. Depending on the application, it may be required for the fiber to enter from the side. To facilitate this, fibers with a machined output face, designed to produce an output at approximately 90 degrees to the fiber axis were tested. Finally, a 2:1 fiber splitter was tested, as a first step to enable simultaneous firing of several detonators. Multiple initiation points are desirable for applications such as programmable initiation, and it is intended to study fiber splitters with a higher split ratio, such as 4:1 and 8:1. The results of these experiments are presented, and assessments made of suitability for transmission of high-power Qswitched Nd:YAG laser pulses.

  16. Integrated Sagnac loop mirror circuit for fiber laser

    NASA Astrophysics Data System (ADS)

    Lee, Tae Ho; Kim, Chang-Seok; Jeong, Myung Yung

    2007-02-01

    Broadband reflection mirror is an important optical device to make a wide resonance bandwidth of the multi-wavelength fiber laser cavity including fiber Bragg grating mirrors. Though a chirped fiber Bragg grating has been used for broadband reflection mirror device, it still requires more improvements in the control of reflection wavelength bandwidth and reflection ratio, which are key design parameters of broadband reflection mirror. In this research, we propose an integrated mirror circuit based on polarization-maintaining fiber Sagnac loop interferometer to utilize for tunable resonance cavity of fiber laser with semiconductor optical amplifier. It is available to control both resonance bandwidth by varying the length of polarization-maintaining fiber and reflection ratio by tuning the polarization state of Sagnac loop. Broad resonance bandwidth of 40 nm could be obtained from Sagnac mirror with thes 0.15 m length of polarization-maintaining fiber.

  17. Laser-machined fibers as Fabry-Perot pressure sensors.

    PubMed

    Watson, Stuart; Gander, Matthew J; MacPherson, William N; Barton, James S; Jones, Julian D C; Klotzbuecher, Thomas; Braune, Torsten; Ott, Johannes; Schmitz, Felix

    2006-08-01

    Cavities have been laser ablated in the ends of single-mode optical fibers and sealed by aluminized polycarbonate diaphragms to produce Fabry-Perot pressure sensors. Both conventional fibers and novel, multicore fibers were used, demonstrating the possibility of producing compact arrays of sensors and multiple sensors on an individual fiber 125 microm in diameter. This high spatial resolution can be combined with high temporal resolution by simultaneously interrogating the sensors by using separate laser sources at three wavelengths. Shock tube tests showed a sensor response time of 3 micros to a step increase in pressure.

  18. 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.

  19. Statistical properties of partially coherent cw fiber lasers.

    PubMed

    Churkin, Dmitriy V; Smirnov, Sergey V; Podivilov, Evgenii V

    2010-10-01

    We perform a detailed quantitative numerical analysis of a partially coherent quasi-cw fiber laser on the example of a high-Q normal dispersion cavity Raman fiber laser. The key role of precise spectral performances of fiber Bragg gratings forming the laser cavity is clarified. It is shown that cross-phase modulation between the pump and Stokes waves does not affect the generation. Amplitudes of different longitudinal modes strongly fluctuate, obeying the Gaussian distribution. As the intensity statistics is noticeably nonexponential, longitudinal modes should be correlated.

  20. Multi-kW cw fiber oscillator pumped by wavelength stabilized fiber coupled diode lasers

    NASA Astrophysics Data System (ADS)

    Becker, Frank; Neumann, Benjamin; Winkelmann, Lutz; Belke, Steffen; Ruppik, Stefan; Hefter, Ulrich; Köhler, Bernd; Wolf, Paul; Biesenbach, Jens

    2013-02-01

    High power Yb doped fiber laser sources are beside CO2- and disk lasers one of the working horses of industrial laser applications. Due to their inherently given robustness, scalability and high efficiency, fiber laser sources are best suited to fulfill the requirements of modern industrial laser applications in terms of power and beam quality. Pumping Yb doped single-mode fiber lasers at 976nm is very efficient. Thus, high power levels can be realized avoiding limiting nonlinear effects like SRS. However the absorption band of Yb doped glass around 976nm is very narrow. Therefore, one has to consider the wavelength shift of the diode lasers used for pumping. The output spectrum of passively cooled diode lasers is mainly defined by the applied current and by the heat sink temperature. Furthermore the overall emission line width of a high power pump source is dominated by the large number of needed diode laser emitters, each producing an individual spectrum. Even though it is possible to operate multi-kW cw single-mode fiber lasers with free running diode laser pumps, wavelength stabilizing techniques for diode lasers (e.g. volume holographic gratings, VHG) can be utilized in future fiber laser sources to increase the output power level while keeping the energy consumption constant. To clarify the benefits of wavelength stabilized diode lasers with integrated VHG for wavelength locking the performance of a dual side pumped fiber oscillator is discussed in this article. For comparison, different pumping configurations consisting of stabilized and free-running diode lasers are presented.

  1. Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

  2. Power scaling of Tm3+ doped ZBLAN blue upconversion fiber lasers: modeling and experiments

    NASA Astrophysics Data System (ADS)

    Qin, G.; Huang, S.; Feng, Y.; Shirakawa, A.; Musha, M.; Ueda, K.-I.

    2006-01-01

    Power scaling of Tm3+ doped ZBLAN blue upconversion fiber lasers was investigated by a simple model. Based on our experimental results on blue fiber lasers, we discuss the effects of photodegradation and photocuring, fiber length, the reflectivity of the coupler mirror and fiber core diameter on further enhancement of blue fiber laser, respectively. The optimal parameters (including fiber length, fiber core diameter and the reflectivity of the coupler mirror) for the operation of high power (>1 W) blue fiber laser were presented through simple numerical simulations, which are valuable for the future design of high power blue upconversion fiber laser.

  3. A novel two-way wavelength division multiplexed fiber laser

    NASA Astrophysics Data System (ADS)

    Ke, Hung-Jen; Chiu, Jian-Lin; Chiang, Chia-Chin; Tsao, Shyh-Lin

    2006-08-01

    We use the fiber loop mirror to form a cavity in our laser system, and two 1.5 μm semiconductor optical amplifier (SOA) also be used as a gain material in the cavity. We analyze the lasing power, SMSR, L-I curve and the stability of our designed symmetric resonator laser with various driving current of the SOA. According to our measured results, we can find that the polarization states of our lasers are stable and the output side-mode suppression ration (SMSR) of our laser is large. We successfully designed a symmetric two-way multi-wavelength wavelength-division-multiplexed (WDM) resonator laser system. The multi-wavelength continuous-wave(CW) fiber laser by utilizing the Fabry-Perot resonance can be applied to PolSK fiber-optic communication systems.

  4. Nd/sup 3 +/-doped cw fiber laser using all-fiber reflectors

    SciTech Connect

    Miller, I.D.; Mortimore, D.B.; Urquhart, P.; Ainslie, B.J.; Craig, S.P.; Miller, C.A.; Payne, D.B.

    1987-06-01

    We demonstrate a novel all-fiber resonant optical cavity which uses two-fiber reflectors, each formed by a single loop of fiber between the output ports of a fiber directional coupler. The reflectivities of the fiber mirrors are each determined by the coupling ratio and the insertion loss of the fused couplers. When the cavity is formed in this way using a continuous length of Nd/sup 3 +/-doped fiber and pumped using a GaAs laser diode, lasing occurs at a wavelength of 1064 nm. Both theoretical and practical descriptions of the device are given.

  5. 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

  6. All fiber-based Yb-doped high energy, high power femtosecond fiber lasers.

    PubMed

    Wan, Peng; Yang, Lih-Mei; Liu, Jian

    2013-12-02

    Two all fiber-based laser systems are demonstrated to achieve high energy and high average power femtosecond pulsed outputs at wavelength of 1 µm. In the high energy laser system, a pulse energy of 1.05 mJ (0.85 mJ after pulse compressor) at 100 kHz repetition rate has been realized by a Yb-doped ultra large-core single-mode photonic crystal fiber (PCF) rod amplifier, seeded with a 50 µJ fiber laser. The pulse duration is 705 fs. In the high average power experiment, a large mode area (LMA) fiber has been used in the final stage amplifier, seeded with a 50 W mode locked fiber laser. The system is running at a repetition rate of 69 MHz producing 1052 W of average power before compressor. After pulse compression, a pulse duration of 800 fs was measured.

  7. High-power thulium-doped fiber laser in an all-fiber configuration

    NASA Astrophysics Data System (ADS)

    Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

    2016-12-01

    High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

  8. Vibrating Optical Fibers to Make Laser Speckle Disappear

    NASA Technical Reports Server (NTRS)

    McGill, Matthew; Scott, V. Stanley

    2005-01-01

    In optical systems in which laser illumination is delivered via multimode optical fibers, laser speckle can be rendered incoherent by a simple but highly effective technique. The need to eliminate speckle arises because speckle can make it difficult to observe edges and other sharp features, thereby making it difficult to perform precision alignment of optical components. The basic ideas of the technique is to vibrate the optical fiber(s) to cause shifting of electromagnetic modes within the fiber(s) and consequent shifting of the speckle pattern in the light emerging from the fiber(s). If the frequency of vibration is high enough, a human eye cannot follow the shifting speckle pattern, so that instead of speckle, a human observer sees a smoothed pattern of light corresponding to a mixture of many electromagnetic modes. If necessary, the optical fiber(s) could be vibrated manually. However, in a typical laboratory situation, it would be more practical to attach a vibrating mechanism to the fiber(s) for routine use as part of the fiber-optic illuminator. In experiments, a commercially available small, gentle, quiet, variable- speed vibratory device was used in this way, with the result that the appearance of speckle was eliminated, as expected. Figures 1 and 2 illustrate the difference.

  9. Modeling compact high power fiber lasers and vecsels

    NASA Astrophysics Data System (ADS)

    Li, Hongbo

    Compact high power fiber lasers and the vertical-external-cavity surface-emitting lasers (VECSELs) are promising candidates for high power laser sources with diffraction-limited beam quality and are currently the subject of intensive research and development. Here three large mode area fiber lasers, namely, the photonic crystal fiber (PCF) laser, the multicore fiber (MCF) laser, and the multimode interference (MMI) fiber laser, as well as the VECSEL are modeled and designed. For the PCF laser, the effective refractive index and the effective core radius of the PCF are investigated using vectorial approaches and reformulated. Then, the classical step-index fiber theory is extended to PCFs, resulting in a highly efficient vectorial effective-index method for the design and analysis of PCFs. The new approach is employed to analyze the modal properties of the PCF lasers with depressed-index cores and to effectively estimate the number of guided modes for PCFs. The MCF laser, consisting of an active MCF and a passive coreless fiber, is modeled using the vectorial mode expansion method developed in this work. The results illustrate that the mode selection in the MCF laser by the coreless fiber section is determined by the MMI effect, not the Talbot effect. Based on the MMI and self-imaging in multimode fibers, the vectorial mode expansion approach is employed to design the first MMI fiber laser demonstrated experimentally. For the design and modeling of VECSELs, the optical, thermal, and structural properties of common material systems are investigated and the most reliable material models are summarized. The nanoscale heat transport theory is applied for the first time, to the best of my knowledge, to design and model VECSELs. In addition, the most accurate strain compensation approach is selected for VECSELs incorporating strained quantum wells to maintain structural stability. The design principles for the VECSEL subcavity are elaborated and applied to design a 1040nm

  10. Linear dissipative soliton in an anomalous-dispersion fiber laser.

    PubMed

    Wang, Ruixin; Dai, Yitang; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong

    2014-12-01

    We report on the generation of linear dissipative soliton (LDS) from an erbium-doped actively mode-locked fiber laser. We show that depending on the down-chirping effect of quadratic phase modulation, instead of the fiber nonlinear Kerr effect in an all-normal-dispersion (ANDi) cavity, stable LDS can be realized in the linear dissipative system. The DS operation of ANDi laser and LDS operation of anomalous dispersion laser are experimentally investigated and compared, and the formation mechanisms of the DS and LDS are discussed. Finally, optical frequency comb generated by the LDS laser is demonstrated.

  11. 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.

  12. 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.

  13. Optical fiber sensing based on reflection laser spectroscopy.

    PubMed

    Gagliardi, Gianluca; Salza, Mario; Ferraro, Pietro; Chehura, Edmond; Tatam, Ralph P; Gangopadhyay, Tarun K; Ballard, Nicholas; Paz-Soldan, Daniel; Barnes, Jack A; Loock, Hans-Peter; Lam, Timothy T-Y; Chow, Jong H; De Natale, Paolo

    2010-01-01

    An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs) and FBG resonators built in fibers of different types are used for strain, temperature and acceleration measurements using heterodyne-detection and optical frequency-locking techniques. Silica fiber-ring cavities are used for chemical sensing based on evanescent-wave spectroscopy. Various arrangements for signal recovery and noise reduction, as an extension of most typical spectroscopic techniques, are illustrated and results on detection performances are presented.

  14. Novel technique for mode selection in a multimode fiber laser.

    PubMed

    Daniel, J M O; Chan, J S P; Kim, J W; Sahu, J K; Ibsen, M; Clarkson, W A

    2011-06-20

    A simple technique for transverse mode selection in a large-mode-area (multimode) fiber laser is described. The technique exploits the different spectral responses of feedback elements based on a fiber Bragg grating and a volume Bragg grating to achieve wavelength-dependent mode filtering. This approach has been applied to a cladding-pumped thulium-doped fiber laser with a multimode core to achieve a single-spatial-mode output beam with a beam propagation factor (M2) of 1.05 at 1923 nm. Without mode selection the free-running fiber laser has a multimode output beam with an M2 parameter of 3.3. Selective excitation of higher order modes is also possible via the technique and preliminary results for laser oscillation on the LP11 mode are also discussed along with the prospects for scaling to higher power levels.

  15. 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.

  16. 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.

  17. 126 W fiber laser at 1018 nm and its application in tandem pumped fiber amplifier

    NASA Astrophysics Data System (ADS)

    Yang, Hening; Zhao, Wei; Si, Jinhai; Zhao, Baoyin; Zhu, Yonggang

    2016-12-01

    We report on a 126 W fiber laser operating at 1018 nm with an optical efficiency of 75%. The optimal length for such a fiber laser is theoretically analyzed using steady-state rate equations including amplified spontaneous emission. Excellent agreement on the maximum output power is achieved between the numerical result and the experimental counterpart. Furthermore, a monolithic tandem pumped fiber amplifier is established by using conventional 30/250 μm double clad ytterbium-doped fiber, and 185 W output power with 85% optical efficiency is realized.

  18. 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.

  19. Investigation of a Pulsed 1550 nm Fiber Laser System

    DTIC Science & Technology

    2015-12-15

    Jain 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT...14. ABSTRACT There is a strong need for a pulsed laser system at eye safe wavelengths for illuminator applications . High power pulsed 1550 nm fiber...system at eye safe wavelengths for illuminator applications . High power pulsed 1550 nm fiber lasers systems are able to generate, shaped, pulses at

  20. 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.

  1. 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.

  2. All-fiber frequency-stabilized erbium doped ring laser.

    PubMed

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

    2010-12-20

    We present an all-fiber frequency-stabilized ring laser system with an integrated reference gas cell consisting of a hollow core fiber filled with acetylene. Through nonlinear absorption spectroscopy the laser frequency is stabilized to a specific absorption line of acetylene. Three different stabilization schemes are investigated and the minimum Allan deviation obtained after 100 s is 4.4 · 10(-11).

  3. Simplified method for numerical modeling of fiber lasers.

    PubMed

    Shtyrina, O V; Yarutkina, I A; Fedoruk, M P

    2014-12-29

    A simplified numerical approach to modeling of dissipative dispersion-managed fiber lasers is examined. We present a new numerical iteration algorithm for finding the periodic solutions of the system of nonlinear ordinary differential equations describing the intra-cavity dynamics of the dissipative soliton characteristics in dispersion-managed fiber lasers. We demonstrate that results obtained using simplified model are in good agreement with full numerical modeling based on the corresponding partial differential equations.

  4. Laser Intensity Scaling Through Stimulated Scattering in Optical Fibers

    DTIC Science & Technology

    2007-11-02

    restriction this imposes on the power of a fiber laser or amplifier. The suppression was modeled using both a holmium dopant and adding a long period grating to...the wavelength of the laser, and the dotted line represents the first order Stokes beam. ......141 Figure 65: Holmium absorption in silicate glass...the molar % of holmium doped into the fiber....................................144 Figure 67: A long period grating couples light out of the core

  5. 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.

  6. Laser diode pumped 106 mW blue upconversion fiber laser

    NASA Astrophysics Data System (ADS)

    Sanders, S.; Waarts, R. G.; Mehuys, D. G.; Welch, D. F.

    1995-09-01

    A laser diode pumped Tm3+-doped ZBLAN fiber upconversion laser is demonstrated with blue output power levels up to 106 mW. Differential optical-to-optical conversion efficiencies up to 30% are measured with respect to pump power coupled into the upconversion fiber. A single spatial mode blue output beam is demonstrated, with an M2 value of 1.4.

  7. 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.

  8. Tapered fiber bundles for combining high-power diode lasers.

    PubMed

    Kosterin, Andrey; Temyanko, Valery; Fallahi, Mahmoud; Mansuripur, Masud

    2004-07-01

    Tapered fiber bundles are often used to combine the output power of several semiconductor lasers into a multimode optical fiber for the purpose of pumping fiber lasers and amplifiers. It is generally recognized that the brightness of such combiners does not exceed the brightness of the individual input fibers. We report that the brightness of the tapered fibers (and fiber bundles) depends on both the taper ratio and the mode-filling properties of the beams launched into the individual fibers. Brightness, therefore, can be increased by selection of sources that fill a small fraction of the input fiber's modal capacity. As proof of concept, we present the results of measurements on tapered fiber-bundle combiners having a low-output étendue. Under low mode-filling conditions per input multimode fiber (i.e., fraction of filled modes < or =0.29), we report brightness enhancements of 8.0 dB for 19 x 1 bundles, 6.7 dB for 7 x 1 bundles, and 4.0 dB for 3 x 1 combiners. Our measured coupling efficiency variations of approximately 1%-2% among the various fibers in a given bundle confirm the uniformity and quality of the fabricated devices.

  9. Fiber inline Michelson interferometer fabricated by a femtosecond laser.

    PubMed

    Yuan, Lei; Wei, Tao; Han, Qun; Wang, Hanzheng; Huang, Jie; Jiang, Lan; Xiao, Hai

    2012-11-01

    A fiber inline Michelson interferometer was fabricated by micromachining a step structure at the tip of a single-mode optical fiber using a femtosecond laser. The step structure splits the fiber core into two reflection paths and produces an interference signal. A fringe visibility of 18 dB was achieved. Temperature sensing up to 1000°C was demonstrated using the fabricated assembly-free device.

  10. Thulium:ZBLAN blue fiber laser pumped by two wavelengths

    NASA Astrophysics Data System (ADS)

    Tohmon, Genji; Sato, Hisanao; Ohya, Jun; Uno, Tomoaki

    1997-05-01

    We demonstrate and analyze an upconversion blue fiber laser pumped by two wavelengths. Lasing at 0.48 m with very low pump threshold power is obtained from a Tm-doped fluorozirconate fiber that is counterpropagating pumped by 1.21- and 0.649- m light. We employed a rate-equation analysis using parameters obtained by fitting to the experimental data to predict the 0.48- m output characteristics as a function of fiber length and output reflectivity.

  11. Thulium:ZBLAN blue fiber laser pumped by two wavelengths.

    PubMed

    Tohmon, G; Sato, H; Ohya, J; Uno, T

    1997-05-20

    We demonstrate and analyze an upconversion blue fiber laser pumped by two wavelengths. Lasing at 0.48 mum with very low pump threshold power is obtained from a Tm-doped fluorozirconate fiber that is counterpropagating pumped by 1.21- and 0.649-mum light. We employed a rate-equation analysis using parameters obtained by fitting to the experimental data to predict the 0.48-mum output characteristics as a function of fiber length and output reflectivity.

  12. Recent development on high-power tandem-pumped fiber laser

    NASA Astrophysics Data System (ADS)

    Zhou, Pu; Xiao, Hu; Leng, Jinyong; Zhang, Hanwei; Xu, Jiangmin; Wu, Jian

    2016-11-01

    High power fiber laser is attracting more and more attention due to its advantage in excellent beam quality, high electricto- optical conversion efficiency and compact system configuration. Power scaling of fiber laser is challenged by the brightness of pump source, nonlinear effect, modal instability and so on. Pumping active fiber by using high-brightness fiber laser instead of common laser diode may be the solution for the brightness limitation. In this paper, we will present the recent development of various kinds of high power fiber laser based on tandem pumping scheme. According to the absorption property of Ytterbium-doped fiber, Thulium-doped fiber and Holmium-doped fiber, we have theoretically studied the fiber lasers that operate at 1018 nm, 1178 nm and 1150 nm, respectively in detail. Consequently, according to the numerical results we have optimized the fiber laser system design, and we have achieved (1) 500 watt level 1018nm Ytterbium-doped fiber laser (2) 100 watt level 1150 nm fiber laser and 100 watt level random fiber laser (3) 30 watt 1178 nm Ytterbium-doped fiber laser, 200 watt-level random fiber laser. All of the above-mentioned are the record power for the corresponded type of fiber laser to the best of our knowledge. By using the high-brightness fiber laser operate at 1018 nm, 1178 nm and 1150 nm that we have developed, we have achieved the following high power fiber laser (1) 3.5 kW 1090 nm Ytterbium-doped fiber amplifier (2) 100 watt level Thulium-doped fiber laser and (3) 50 watt level Holmium -doped fiber laser.

  13. 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.

  14. 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.

  15. Mid-Infrared Fiber Laser Based on Super-Continuum

    DTIC Science & Technology

    2007-01-31

    the pump wavelength. The gain fiber comprises a.lm of highly doped, large mode area ( LMA ) erbium-doped fiber amplifier (EDFA). Two 1480nm pump laser...amplified stimulation emission. In addition, the LMA EDFA can be incorporated and spliced into the pump laser set-up, and up to several Omni Sciences...Outputnput from 5m Nufern Er/Yb ~2SF ~0mL# gain fiber 71125 pm 6W 976nm pump Figure 4. Detailed lay-out for power amplifier stage using cladding

  16. A 532 nm Chaotic Fiber Laser Transmitter for Underwater Lidar

    DTIC Science & Technology

    2013-04-23

    cooling to deal with the heat. There are no direct solid-state blue-green transitions, but neodymium -doped YAG crystal lasers (Nd:YAG)) is commonly...dopants include neodymium , thulium, praseodymium, yt- terbium, and erbium, but the latter two are by far the most common. Erbium-doped fiber lasers

  17. 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.

  18. All-fiber ring Raman laser generating parabolic pulses

    SciTech Connect

    Kruglov, V. I.; Mechin, D.; Harvey, J. D.

    2010-02-15

    We present theoretical and numerical results for an all-fiber laser using self-similar parabolic pulses ('similaritons') designed to operate using self-similar propagation regimes. The similariton laser features a frequency filter and a Sagnac loop which operate together to generate an integrated all-fiber mode-locked laser. Numerical studies show that this laser generates parabolic pulses with linear chirp in good agreement with analytical predictions. The period for propagating similariton pulses in stable regimes can vary from one to two round trips for different laser parameters. Two-round-trip-period operation in the mode-locked laser appears at bifurcation points for certain cavity parameters. The stability of the similariton regimes has been confirmed by numerical simulations for large numbers of round trips.

  19. High-power disk and fiber lasers: a performance comparison

    NASA Astrophysics Data System (ADS)

    Ruppik, Stefan; Becker, Frank; Grundmann, Frank-Peter; Rath, Wolfram; Hefter, Ulrich

    2012-03-01

    The Performance of High Power Disk Lasers and Fiber Lasers along with their rapid development to the high power cw regime have been of great interest throughout the last decade. Both technologies are still in the focus of several conferences, workshops, and papers and represent the "state-of-the-art" of industrial high power solid state lasers for material processing. As both laser concepts are considered to be the leading 1 μm light-source, this presentation presents an objective and fair comparison of the two different technologies from a manufacturer who pursued both. From the geometry of the active material, through the resonator design, cooling regime, and pumping method to the point of beam quality and power scaling, the different approaches associated with the advantages, challenge and limits of each technology will be discussed. Based on ROFIN's substantial industrial experience with both laser concepts, an outlook into future trends and chances, especially linked to fiber laser, will be given.

  20. Sideband-controllable mode-locking fiber laser based on chirped fiber Bragg gratings.

    PubMed

    Han, Dongdong; Liu, Xueming

    2012-11-19

    We have proposed a sideband-controllable fiber soliton laser by means of chirped fiber Bragg gratings (CFBGs). Each side of the spectral sidebands of laser could be removed by using a CFBG with proper dispersion. Numerical simulations have well reproduced the experimental observations. The numerical and experimental investigations show that the generation of the unilateral sidebands is attributed to the CFBG-induced spectral filtering effect. Our work provides an effective way to manage conventional solitons with spectral sidebands.

  1. Efficiency of Laser Cutting of Carbon Fiber Textiles

    NASA Astrophysics Data System (ADS)

    Fuchs, Alexander N.; Zaeh, Michael F.

    Laser cutting of carbon fiber textiles has various advantages over conventional processes like ultrasonic knife cutting: It is wear free, no fibers are left uncut in the kerf, it is able to cut complex contours, and the cut edge is clearly defined. To ensure a complete cut under variable conditions, e.g. the thickness of the material, line energy has to be applied at a higher level than theoretically necessary to account for those variations. This energy is transilluminated through the kerf. In addition, not all laser energy is absorbed by the fibers but reflected and transmitted within the space between the fibers. Experiments were carried out to measure the percentage of laser power transilluminated through multi-layered carbon fiber textiles during laser cutting with maximum speed. To do so, blocks of poly(methyl methacrylate) (PMMA) were placed underneath the samples and the mass of the sublimed material was measured. Depending on the angle of the fiber, between 9% and 40% of the laser power was transilluminated.

  2. 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.

  3. 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.

  4. 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.

  5. Single-crystal silicon optical fiber by direct laser crystallization

    SciTech Connect

    Ji, Xiaoyu; Lei, Shiming; Yu, Shih -Ying; Cheng, Hiu Yan; Liu, Wenjun; Poilvert, Nicolas; Xiong, Yihuang; Dabo, Ismaila; Mohney, Suzanne E.; Badding, John V.; Gopalan, Venkatraman

    2016-12-05

    Semiconductor core optical fibers with a silica cladding are of great interest in nonlinear photonics and optoelectronics applications. Laser crystallization has been recently demonstrated for crystallizing amorphous silicon fibers into crystalline form. Here we explore the underlying mechanism by which long single-crystal silicon fibers, which are novel platforms for silicon photonics, can be achieved by this process. Using finite element modeling, we construct a laser processing diagram that reveals a parameter space within which single crystals can be grown. Utilizing this diagram, we illustrate the creation of single-crystal silicon core fibers by laser crystallizing amorphous silicon deposited inside silica capillary fibers by high-pressure chemical vapor deposition. The single-crystal fibers, up to 5.1 mm long, have a very welldefined core/cladding interface and a chemically pure silicon core that leads to very low optical losses down to ~0.47-1dB/cm at the standard telecommunication wavelength (1550 nm). Furthermore, tt also exhibits a photosensitivity that is comparable to bulk silicon. Creating such laser processing diagrams can provide a general framework for developing single-crystal fibers in other materials of technological importance.

  6. Single-crystal silicon optical fiber by direct laser crystallization

    DOE PAGES

    Ji, Xiaoyu; Lei, Shiming; Yu, Shih -Ying; ...

    2016-12-05

    Semiconductor core optical fibers with a silica cladding are of great interest in nonlinear photonics and optoelectronics applications. Laser crystallization has been recently demonstrated for crystallizing amorphous silicon fibers into crystalline form. Here we explore the underlying mechanism by which long single-crystal silicon fibers, which are novel platforms for silicon photonics, can be achieved by this process. Using finite element modeling, we construct a laser processing diagram that reveals a parameter space within which single crystals can be grown. Utilizing this diagram, we illustrate the creation of single-crystal silicon core fibers by laser crystallizing amorphous silicon deposited inside silica capillarymore » fibers by high-pressure chemical vapor deposition. The single-crystal fibers, up to 5.1 mm long, have a very welldefined core/cladding interface and a chemically pure silicon core that leads to very low optical losses down to ~0.47-1dB/cm at the standard telecommunication wavelength (1550 nm). Furthermore, tt also exhibits a photosensitivity that is comparable to bulk silicon. Creating such laser processing diagrams can provide a general framework for developing single-crystal fibers in other materials of technological importance.« less

  7. 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.

  8. 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.

  9. Development of ceramic fibers for high-energy laser applications

    NASA Astrophysics Data System (ADS)

    Fair, Geoff E.; Kim, Hyun Jun; Lee, HeeDong; Parthasarathy, Triplicane A.; Keller, Kristin A.; Miller, Zachary D.

    2011-06-01

    Polycrystalline ceramics offer a number of advantages relative to single crystal materials such as lower processing temperatures, improved mechanical properties, and higher doping levels with more uniform distribution of dopants for improved laser performance. Ceramic YAG (Y3Al5O12) and rare earth sesquioxide (RE2O3) fibers promise to enable a number of high power laser devices via high thermal conductivity and higher allowable dopant concentration; however, these materials are not currently available as fine diameter optical-quality fibers. Powder processing approaches for laser quality polycrystalline ceramic fibers are in development at AFRL. Current processing techniques will be reviewed. The effects of a number of processing variables on the resulting fibers as well as preliminary optical characterization will also be presented.

  10. 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.

  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. Cracks measurement using fiber-phased array laser ultrasound generation

    NASA Astrophysics Data System (ADS)

    Pei, Cuixiang; Demachi, Kazuyuki; Fukuchi, Tetsuo; Koyama, Kazuyoshi; Uesaka, Mitsuru

    2013-04-01

    A phased array laser ultrasound generation system by using fiber optic delivery and a custom-designed focusing objective lens has been developed for crack inspection. The enhancement of crack tip diffraction by using phased array laser ultrasound is simulated with finite element method and validated by experiment. A non-contact and non-destructive measurement of inner-surface cracks by time-of-flight diffraction method using fiber-phased array laser ultrasound generation and electromagnetic acoustic transducer detection has been studied.

  13. Non-resonant wavelength modulation saturation spectroscopy in acetylene-filled hollow-core photonic bandgap fibres applied to modulation-free laser diode stabilisation.

    PubMed

    Pineda-Vadillo, Pablo; Lynch, Michael; Charlton, Christy; Donegan, John F; Weldon, Vincent

    2009-12-07

    In this paper the application of Wavelength Modulation (WM) techniques to non-resonant saturation spectroscopy in acetylene-filled Hollow-Core Photonic Bandgap Fibres (HC-PBFs) and modulation-free Laser Diode (LD) frequency stabilisation is investigated. In the first part WM techniques are applied to non-resonant pump-probe saturation of acetylene overtone rotational transitions in a HC-PBF. A high-power DFB chip-on-carrier mounted LD is used in conjunction with a tuneable External Cavity Laser (ECL) and the main saturation parameters are characterized. In the second part a novel feedback system to stabilize the DFB emission wavelength based on the WM saturation results is implemented. Modulation-free locking of the DFB laser frequency to the narrow linewidth saturation feature is achieved for both constant and variable LD temperatures.

  14. Transportation of megawatt millijoule laser pulses via optical fibers?

    NASA Astrophysics Data System (ADS)

    Tauer, Johannes; Kofler, Heinrich; Schwarz, Elisabeth; Wintner, Ernst

    2010-04-01

    Laser ignition is considered to be one of the most promising future concepts for internal combustion engines. It combines the legally required reduction of pollutant emissions and higher engine efficiencies. The igniting plasma is generated by a focused pulsed laser beam. Having pulse durations of a few nanoseconds, the pulse energy E p for reliable ignition amounts to the order of 10 mJ. Different methods of laser ignition with an emphasis on fiber-based systems will be discussed and evaluated.

  15. 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.

  16. Frequency noise induced by fiber perturbations in a fiber-linked stabilized laser

    NASA Technical Reports Server (NTRS)

    Pang, YI; Hamilton, Jeffrey J.; Richard, Jean-Paul

    1992-01-01

    The effects of acoustic perturbations on an optical fiber that links a stabilized laser to its reference cavity are studied. An extrapolation indicates that 69 dB of acoustic noise impinging on a 1-m segment of the 10-m fiber contribute frequency noise at the level of 1 Hz/(Hz)1/2 in the 1100-2100-Hz band.

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

    PubMed

    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. Plume attenuation of laser radiation during high power fiber laser welding

    NASA Astrophysics Data System (ADS)

    Shcheglov, P. Yu; Uspenskiy, S. A.; Gumenyuk, A. V.; Petrovskiy, V. N.; Rethmeier, M.; Yermachenko, V. M.

    2011-06-01

    The results of an in-situ plume-laser interaction measurement during welding of mild steel with a 5 kW ytterbium fiber laser are reported. A measurement of the attenuation of probe laser beam passing through the plume has allowed to estimate the plume characteristics like the size of the extinction area and the spatial distribution of the extinction coefficient. The power loss of the fiber laser radiation propagating through the whole plume length was calculated. Together with a measured temporal characteristics of extinction the result indicates a significant decreasing of the laser radiation stability, which can lead to the formation of the macroscopic welding defects.

  19. 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.

  20. 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.

  1. 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.

  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. Fiber laser as the pulse source for a laser rangefinder system

    NASA Astrophysics Data System (ADS)

    Nissilae, Seppo M.; Kostamovaara, Juha T.

    1993-05-01

    Active fibers, i.e. optically pumped doped fibers, have been developed and studied intensively during the last few years, and an optical amplifier based mainly on erbium-doped fibers has just been launched on the expanding telecommunications market. Fiber lasers have a market of their own in the sensor applications. The use of fiber lasers as pulse sources in laser rangefinder applications is studied here. The main advantages with respect to high energy pulses and a small emitting area are listed, the problems and disadvantages are discussed and some practical solutions to these problems are given. Possible Q-switching techniques for obtaining short, powerful pulses (> 10 W) of about 10 ns are studied as are liquid-crystal, PLZT crystal, acousto-optic and Pockels Cell modulators. Finally, the practicability of these modulators for laser pulsing in industrial environments is discussed.

  4. Incoherent Combining of High-Power Fibers Lasers for Long-Range Directed Energy Applications

    DTIC Science & Technology

    2006-06-27

    Europe meeting IPG Photonics reported [2] CW powers of 2 kW at a wavelength of A = 1.075/.n from a ytterbium fiber laser . The fiber laser operated in a...propagation of the laser beams from the fiber array of Fig. 6 to the target. HELCAP is a 3 -dimensional, fully time-dependent, nonlinear atmospheric...configuration uses recently-developed, multi- kilowatt fiber lasers . These lasers , however, are not suitable for coherent beam combining because of their

  5. Fiber laser hydrogen sensor codified in the time domain

    NASA Astrophysics Data System (ADS)

    Barmenkov, Yuri O.; Ortigosa-Blanch, Arturo; Diez, Antonio; Cruz Munoz, Jose Luis; Andres, Miguel V.

    2004-10-01

    A novel scheme for a fiber optic hydrogen sensor is presented. The sensor is based on an erbium-doped fiber laser with a Pd-coated tapered fiber within the laser cavity acting as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses, which leads to a modification of the switching-on laser transient. The hydrogen concentration can be obtained by a simple measurement of the build-up time of the laser. This technique translates the measurement of hydrogen concentration into the time domain. Sensing techniques translating the measurement to the time domain offer the possibility to acquire and process the information very easily and accurately using reliable and low-cost electronics. We have also studied the influence of the pumping conditions. We have found that changing from a 100% modulation depth of the pump to biasing the laser with a certain pump power (being this value always below the laser threshold) the sensitivity of the sensor is substantially enhanced. Hence the sensitivity of the fiber laser sensor can be adjusted to certain requirements by simply controlling the pump. Relative build-up times variations of up to 55% for 10% hydrogen concentration are demonstrated.

  6. Quasi mode-locking of coherent feedback random fiber laser

    NASA Astrophysics Data System (ADS)

    Ma, R.; Zhang, W. L.; Zeng, X. P.; Yang, Z. J.; Rao, Y. J.; Yao, B. C.; Yu, C. B.; Wu, Y.; Yu, S. F.

    2016-12-01

    Mode-locking is a milestone in the history of lasers that allows the generation of short light pulses and stabilization of lasers. This phenomenon is known to occur only in standard ordered lasers for long time and until recently it is found that it also occurs in disordered random lasers formed by nanoscale particles. Here, we report the realization of a so-called quasi mode-locking of coherent feedback random fiber laser which consists of a partially disordered linear cavity formed between a point reflector and a random distributed fiber Bragg grating array with an inserted graphene saturable absorber. We show that multi-groups of regular light pulses/sub-pulses with different repetition frequencies are generated within the quasi mode-locking regime through the so-called collective resonances phenomenon in such a random fiber laser. This work may provide a platform to study mode locking as well as pulse dynamic regulation of random lasing emission of coherent feedback disordered structures and pave the way to the development of novel multi-frequency pulse fiber lasers with potentially wide frequency tuning range.

  7. Quasi mode-locking of coherent feedback random fiber laser

    PubMed Central

    Ma, R.; Zhang, W. L.; Zeng, X. P.; Yang, Z. J.; Rao, Y. J.; Yao, B. C.; Yu, C. B.; Wu, Y.; Yu, S. F.

    2016-01-01

    Mode-locking is a milestone in the history of lasers that allows the generation of short light pulses and stabilization of lasers. This phenomenon is known to occur only in standard ordered lasers for long time and until recently it is found that it also occurs in disordered random lasers formed by nanoscale particles. Here, we report the realization of a so-called quasi mode-locking of coherent feedback random fiber laser which consists of a partially disordered linear cavity formed between a point reflector and a random distributed fiber Bragg grating array with an inserted graphene saturable absorber. We show that multi-groups of regular light pulses/sub-pulses with different repetition frequencies are generated within the quasi mode-locking regime through the so-called collective resonances phenomenon in such a random fiber laser. This work may provide a platform to study mode locking as well as pulse dynamic regulation of random lasing emission of coherent feedback disordered structures and pave the way to the development of novel multi-frequency pulse fiber lasers with potentially wide frequency tuning range. PMID:28004785

  8. 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%.

  9. 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.

  10. Nearly-octave wavelength tuning of a continuous wave fiber laser.

    PubMed

    Zhang, Lei; Jiang, Huawei; Yang, Xuezong; Pan, Weiwei; Cui, Shuzhen; Feng, Yan

    2017-02-15

    The wavelength tunability of conventional fiber lasers are limited by the bandwidth of gain spectrum and the tunability of feedback mechanism. Here a fiber laser which is continuously tunable from 1 to 1.9 μm is reported. It is a random distributed feedback Raman fiber laser, pumped by a tunable Yb doped fiber laser. The ultra-wide wavelength tunability is enabled by the unique property of random distributed feedback Raman fiber laser that both stimulated Raman scattering gain and Rayleigh scattering feedback are available at any wavelength. The dispersion property of the gain fiber is used to control the spectral purity of the laser output.

  11. Nearly-octave wavelength tuning of a continuous wave fiber laser

    PubMed Central

    Zhang, Lei; Jiang, Huawei; Yang, Xuezong; Pan, Weiwei; Cui, Shuzhen; Feng, Yan

    2017-01-01

    The wavelength tunability of conventional fiber lasers are limited by the bandwidth of gain spectrum and the tunability of feedback mechanism. Here a fiber laser which is continuously tunable from 1 to 1.9 μm is reported. It is a random distributed feedback Raman fiber laser, pumped by a tunable Yb doped fiber laser. The ultra-wide wavelength tunability is enabled by the unique property of random distributed feedback Raman fiber laser that both stimulated Raman scattering gain and Rayleigh scattering feedback are available at any wavelength. The dispersion property of the gain fiber is used to control the spectral purity of the laser output. PMID:28198414

  12. 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

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

    PubMed

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

    2015-02-09

    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.

  14. Hybrid lasing in an ultra-long ring fiber laser.

    PubMed

    Rao, Y J; Zhang, W L; Zhu, J M; Yang, Z X; Wang, Z N; Jia, X H

    2012-09-24

    In this paper, we reported the realization of an ultra-long ring fiber laser (RFL) with hybrid emission related to both random lasing and cavity resonance. Compared with a linear random fiber laser (LRFL), the Rayleigh scattering (RS) inducting distributed feedback effect and the cavity inducting resonance effect exist simultaneously in the laser, which reduces the lasing threshold considerably and provides a hybrid way to form random lasing (RL). The laser output can be purely modeless RL when pump power is high enough. It is also discovered that the laser is insensitive to temperature variation and mechanical disturbance, this is unique and quite different from conventional RFLs which are environmentally unstable due to existence of the cavity modes.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Dual frequency comb metrology with one fiber laser

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Takeshi, Yasui; Zheng, Zheng

    2016-11-01

    Optical metrology techniques based on dual optical frequency combs have emerged as a hotly studied area targeting a wide range of applications from optical spectroscopy to microwave and terahertz frequency measurement. Generating two sets of high-quality comb lines with slightly different comb-tooth spacings with high mutual coherence and stability is the key to most of the dual-comb schemes. The complexity and costs of such laser sources and the associated control systems to lock the two frequency combs hinder the wider adoption of such techniques. Here we demonstrate a very simple and rather different approach to tackle such a challenge. By employing novel laser cavity designs in a mode-locked fiber laser, a simple fiber laser setup could emit dual-comb pulse output with high stability and good coherence between the pulse trains. Based on such lasers, comb-tooth-resolved dual-comb optical spectroscopy is demonstrated. Picometer spectral resolving capability could be realized with a fiber-optic setup and a low-cost data acquisition system and standard algorithms. Besides, the frequency of microwave signals over a large range can be determined based on a simple setup. Our results show the capability of such single-fiber-laser-based dual-comb scheme to reduce the complexity and cost of dual-comb systems with excellent quality for different dual-comb applications.

  20. A phase-stabilized carbon nanotube fiber laser frequency comb.

    PubMed

    Lim, Jinkang; Knabe, Kevin; Tillman, Karl A; Neely, William; Wang, Yishan; Amezcua-Correa, Rodrigo; Couny, François; Light, Philip S; Benabid, Fetah; Knight, Jonathan C; Corwin, Kristan L; Nicholson, Jeffrey W; Washburn, Brian R

    2009-08-03

    A frequency comb generated by a 167 MHz repetition frequency erbium-doped fiber ring laser using a carbon nanotube saturable absorber is phase-stabilized for the first time. Measurements of the in-loop phase noise show an integrated phase error on the carrier envelope offset frequency of 0.35 radians. The carbon nanotube fiber laser comb is compared with a CW laser near 1533 nm stabilized to the nu(1) + nu(3) overtone transition in an acetylene-filled kagome photonic crystal fiber reference, while the CW laser is simultaneously compared to another frequency comb based on a Cr:Forsterite laser. These measurements demonstrate that the stability of a GPS-disciplined Rb clock is transferred to the comb, resulting in an upper limit on the locked comb's frequency instability of 1.2 x 10(-11) in 1 s, and a relative instability of <3 x 10(-12) in 1 s. The carbon nanotube laser frequency comb offers much promise as a robust and inexpensive all-fiber frequency comb with potential for scaling to higher repetition frequencies.

  1. 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.

  2. Nd-doped phosphate glass microstructured optical fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Luo, F. F.; Liu, X. F.; Dong, G. P.; Zhang, Q.; Lin, G.; Zhou, Q. L.; Qiu, J. R.; Hu, L. L.; Chen, D. P.

    2010-06-01

    We experimentally demonstrated a single-mode laser at 1056 nm with Nd-doped phosphate glass microstructured optical fiber (MOF), which was fabricated with conventional stack-and-draw method. The laser action was observed from a Fabry-Perot cavity formed by placing two dichroic mirrors of ˜100 and 85% reflectivity, to the two end facets of MOF. Pumped by CW laser diodes (LDs) at 808 nm, the MOF laser yielded a maximum output power of 8.5 mW and a slope efficiency of 2%.

  3. 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.

  4. 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.

  5. 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.

  6. 157 W all-fiber high-power picosecond laser.

    PubMed

    Song, Rui; Hou, Jing; Chen, Shengping; Yang, Weiqiang; Lu, Qisheng

    2012-05-01

    An all-fiber high-power picosecond laser is constructed in a master oscillator power amplifier configuration. The self-constructed fiber laser seed is passively mode locked by a semiconductor saturable absorber mirror. Average output power of 157 W is obtained after three stages of amplification at a fundamental repetition rate of 60 MHz. A short length of ytterbium double-clad fiber with a high doping level is used to suppress nonlinear effects. However, a stimulated Raman scattering (SRS) effect occurs owing to the 78 kW high peak power. A self-made all-fiber repetition rate increasing system is used to octuple the repetition rate and decrease the high peak power. Average output power of 156.6 W is obtained without SRS under the same pump power at a 480 MHz repetition rate with 0.6 nm line width.

  7. Clad Nd:YAG fibers for laser applications

    SciTech Connect

    Digonnet, M.J.F.; Shaw, H.J.; Gaeta, C.J.; O'meara, D.

    1987-05-01

    The implementation of an extrusion method to clad Nd:YAG single crystal fibers with index-matched glasses (Delta-n = 0.048) is reported. A propagation-loss coefficient of 0.08 dB/cm was measured for the fundamental mode of a 41-micron-diameter glass-clad fiber laser, an improvement of about one order of magnitude over unclad fibers. Guided clad fiber lasers operated at 1.064 microns with thresholds as low as 0.3-0.5 mW and up to 65-mW CW output power are also reported. The origins of and means of reducing the residual loss are discussed. 14 references.

  8. Subhertz linewidth laser by locking to a fiber delay line.

    PubMed

    Dong, Jing; Hu, Yongqi; Huang, Junchao; Ye, Meifeng; Qu, Qiuzhi; Li, Tang; Liu, Liang

    2015-02-10

    An ultralow-noise, subhertz 1.55 μm erbium-doped fiber laser that is locked on an all-fiber-based Michelson interferometer is presented in this paper. The interferometer uses 500 m SMF-28 optical fiber and an acousto-optic modulator to allow heterodyne detection. By comparing two identical laser systems, a 0.67 (0.21) Hz linewidth beat-note signal is achieved and we obtain fractional frequency instability of 7×10(-15) at short timescales (0.1-1 s). The frequency noise power spectral density of two identical lasers is below -1  dB Hz(2)/Hz at 1 Hz and it reaches -18  dB Hz(2)/Hz from 200 Hz to 1 kHz.

  9. Rare Earth Doped IR Fiber Lasers For Medical Applications

    NASA Astrophysics Data System (ADS)

    Esterowitz, Leon; Allen, Roger

    1989-06-01

    Trivalent rare earth doped lasers in fluorozirconate glasses and fibers that lase between 2 and 3 μm are reviewed. There have been a large number of laser-fiber optic systems below 2pm developed for clinical microsurgery at a variety of sites. The required flexibility of the fiber optic waveguide varies with the clinical use, such as: intraocular (through a small diameter rigid tube), endoscopically accessible pulmonary and gastric mucosa (through a port of a fiber-optic endoscope of intermediate flexibility), and intra-arterial (as an integral part of a flexible catheter, which in the case of the coronaries must be very flexible so as to negotiate abrupt bends and bifurcations without damage to the vessels). Laser energy absorbed by tissue is capable of coagulation of tissue (denaturation of structural proteins), melting of fatty deposits or other structures (solid or gel to liquid phase transitions), as well as direct breakage of chemical bonds by high energy photons. It is of general interest to develop a pulsed laser system transmitted through flexible fiber optics that is capable of precise ablation of targeted tissue with minimal damage to the remaining tissue. Ideally, the device should be able to ablate any tissue because of the general absorptive properties of tissue, and not a specific chromophore such as melanin or hemoglobin, the concentration of which varies widely among tissues. Two obvious ubiquitous chromophores have been widely discussed: 1) proteins and nucleic acids whose high concentration and absorption coefficients lead to strong tissue absorption in the ultraviolet and 2) water whose strong infrared absorption bands have been widely utilized in CO2 laser surgery. Non-linear absorption occurring at very high power densities (~1 GW/cm2) has been shown to be very effective for non-invasive ocular (an optically transparent field) microsurgery at the image plane of a slit lamp, but this approach appears impractical in fiber optic systems because

  10. 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.

  11. Stable two-wavelength lasers by use of a double alpha-type fiber cavity with fiber grating mirrors

    NASA Astrophysics Data System (ADS)

    Kim, Ho-Young; Oh, Myoung-Suk; Nam, Eun-Soo; Cho, Kyoung-Ik

    2005-12-01

    For high-frequency (20-200 GHz) modulated light sources, we developed and investigated two-wavelength lasers using the double alpha-type fiber cavities with fiber grating mirrors. For variations of polarization states and pump powers, parallel alpha-type coupled cavity lasers were found to be more stable than serial lasers.

  12. Power optimization of random distributed feedback fiber lasers.

    PubMed

    Vatnik, Ilya D; Churkin, Dmitry V; Babin, Sergey A

    2012-12-17

    We present a comprehensive study of power output characteristics of random distributed feedback Raman fiber lasers. The calculated optimal slope efficiency of the backward wave generation in the one-arm configuration is shown to be as high as ~90% for 1 W threshold. Nevertheless, in real applications a presence of a small reflection at fiber ends can appreciably deteriorate the power performance. The developed numerical model well describes the experimental data.

  13. Fiber-Laser-Based Ultrasound Sensor for Photoacoustic Imaging

    NASA Astrophysics Data System (ADS)

    Liang, Yizhi; Jin, Long; Wang, Lidai; Bai, Xue; Cheng, Linghao; Guan, Bai-Ou

    2017-01-01

    Photoacoustic imaging, especially for intravascular and endoscopic applications, requires ultrasound probes with miniature size and high sensitivity. In this paper, we present a new photoacoustic sensor based on a small-sized fiber laser. Incident ultrasound waves exert pressures on the optical fiber laser and induce harmonic vibrations of the fiber, which is detected by the frequency shift of the beating signal between the two orthogonal polarization modes in the fiber laser. This ultrasound sensor presents a noise-equivalent pressure of 40 Pa over a 50-MHz bandwidth. We demonstrate this new ultrasound sensor on an optical-resolution photoacoustic microscope. The axial and lateral resolutions are 48 μm and 3.3 μm. The field of view is up to 1.57 mm2. The sensor exhibits strong resistance to environmental perturbations, such as temperature changes, due to common-mode cancellation between the two orthogonal modes. The present fiber laser ultrasound sensor offers a new tool for all-optical photoacoustic imaging.

  14. Fiber-Laser-Based Ultrasound Sensor for Photoacoustic Imaging

    PubMed Central

    Liang, Yizhi; Jin, Long; Wang, Lidai; Bai, Xue; Cheng, Linghao; Guan, Bai-Ou

    2017-01-01

    Photoacoustic imaging, especially for intravascular and endoscopic applications, requires ultrasound probes with miniature size and high sensitivity. In this paper, we present a new photoacoustic sensor based on a small-sized fiber laser. Incident ultrasound waves exert pressures on the optical fiber laser and induce harmonic vibrations of the fiber, which is detected by the frequency shift of the beating signal between the two orthogonal polarization modes in the fiber laser. This ultrasound sensor presents a noise-equivalent pressure of 40 Pa over a 50-MHz bandwidth. We demonstrate this new ultrasound sensor on an optical-resolution photoacoustic microscope. The axial and lateral resolutions are 48 μm and 3.3 μm. The field of view is up to 1.57 mm2. The sensor exhibits strong resistance to environmental perturbations, such as temperature changes, due to common-mode cancellation between the two orthogonal modes. The present fiber laser ultrasound sensor offers a new tool for all-optical photoacoustic imaging. PMID:28098201

  15. Parabolic similariton Yb-fiber laser with triangular pulse evolution

    NASA Astrophysics Data System (ADS)

    Wang, Sijia; Wang, Lei

    2016-04-01

    We propose a novel mode-locked fiber laser design which features a passive nonlinear triangular pulse formation and self-similar parabolic pulse amplification intra cavity. Attribute to the nonlinear reshaping progress in the passive fiber, a triangular-profiled pulse with negative-chirp is generated and paved the way for rapid and efficient self-similar parabolic evolution in a following short-length high-gain fiber. In the meanwhile, the accompanied significantly compressed narrow spectrum from this passive nonlinear reshaping also gives the promise of pulse stabilization and gain-shaping robustness without strong filtering. The resulting short average intra-cavity pulse duration, low amplified spontaneous emission (ASE) and low intra-cavity power loss are essential for the low-noise operation. Simulations predict this modelocked fiber laser allows for high-energy ultra-short transform-limited pulse generation exceeding the gain bandwidth. The output pulse has a de-chirped duration (full-width at half maximum, FWHM) of 27 fs. In addition to the ultrafast laser applications, the proposed fiber laser scheme can support low-noise parabolic and triangular pulse trains at the same time, which are also attractive in optical pulse shaping, all-optical signal processing and high-speed communication applications.

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Ladany, I.

    1992-07-01

    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.

  19. Fast Fiber-Laser Alignment: Beam Spot-Size Method

    NASA Astrophysics Data System (ADS)

    Zhang, Rong; Guo, Jingyan; Shi, Frank G.

    2005-03-01

    A novel fast and cost-effective method is introduced for the active alignment of a fiber to a laser diode: only four easy laser beam spot-size measurements are required for moving the fiber tip from the far field to the proximity of the optimal alignment position, thus dramatically reducing the total alignment time (at least five times faster than a conventional method),as experimentally confirmed. Moreover, in contrast to the existing methods,the new method is failure-proof. The principle of the proposed method can be applied generally to any type of packages and is illustrated by an example of a butterfly package.

  20. Theoretical analysis of spectrum flattening in fiber laser oscillator

    NASA Astrophysics Data System (ADS)

    Shi, Chen; Wang, Xiaolin; Zhou, Pu; Wang, Zefeng; Xu, Xiaojun; Lu, Qisheng

    2017-01-01

    The flatness of laser spectrum is important in many applications. In this manuscript, a method of acquiring flattened spectrum directly from a fiber oscillator by optimizing the reflective spectrum of Fiber Bragg Gratings (FBG) was demonstrated and optimized result at wavelength around 1064 nm and 1080 nm was presented. An optimization path to alter the reflectivity of FBGs using greedy algorithm was interpreted by analyzing the single-trip gain inside the resonant cavity. Our method has a guiding significance of controlling the output spectrum of laser oscillator using FBGs.

  1. 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.

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

    PubMed

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

    2011-05-23

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

  3. 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)

  4. Molecular Gas-Filled Hollow Optical Fiber Lasers in the Near Infrared

    DTIC Science & Technology

    2012-01-12

    HOLLOW OPTICAL FIBER LASERS IN THE NEAR F A9550-08-l-0344 INFRARED Sb. GRANT NUMBER Sc. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sd. PROJECT NUMBER...SUPPLEMENTARY NOTES 14. ABSTRACT We have demonstrated of a new class of optically pumped gas lasers inside a hollow-core photonic crystal fibers . Here, a...crystal fiber . These lasers are the first in a new class of infrared lasers based on the combination of hollow- fiber and optically pumped-gas

  5. Picosecond passively mode-locked mid-infrared fiber laser

    NASA Astrophysics Data System (ADS)

    Wei, C.; Zhu, X.; Norwood, R. A.; Kieu, K.; Peyghambarian, N.

    2013-02-01

    Mode-locked mid-infrared (mid-IR) fiber lasers are of increasing interest due to their many potential applications in spectroscopic sensors, infrared countermeasures, laser surgery, and high-efficiency pump sources for nonlinear wavelength convertors. Er3+-doped ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) fiber lasers, which can emit mid-IR light at 2.65-2.9 μm through the transition from the upper energy level 4I11/2 to the lower laser level 4I13/2, have attracted much attention because of their broad emission range, high optical efficiency, and the ready availability of diode pump lasers at the two absorption peaks of Er3+ ions (975 nm and 976 nm). In recent years, significant progress on high power Er3+- doped ZBLAN fiber lasers has been achieved and over 20 watt cw output at 2.8 μm has been demonstrated; however, there has been little progress on ultrafast mid-IR ZBLAN fiber lasers to date. We report a passively mode-locked Er3+- doped ZBLAN fiber laser in which a Fe2+:ZnSe crystal was used as the intracavity saturable absorber. Fe2+:ZnSe is an ideal material for mid-IR laser pulse generation because of its large saturable absorption cross-section and small saturation energy along with the excellent opto-mechanical (damage threshold ~2 J/cm2) and physical characteristics of the crystalline ZnSe host. A 1.6 m double-clad 8 mol% Er3+-doped ZBLAN fiber was used in our experiment. The fiber core has a diameter of 15 μm and a numerical aperture (NA) of 0.1. The inner circular cladding has a diameter of 125 μm and an NA of 0.5. Both continuous-wave and Q-switched mode-locking pulses at 2.8 μm were obtained. Continuous-wave mode locking operation with a pulse duration of 19 ps and an average power of 51 mW were achieved when a collimated beam traversed the Fe2+:ZnSe crystal. When the cavity was modified to provide a focused beam at the Fe2+:ZnSe crystal, Q-switched mode-locked operation with a pulse duration of 60 ps and an average power of 4.6 mW was achieved. More powerful

  6. 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.

  7. Thulium:ZBLAN blue fiber laser pumped by two wavelengths

    SciTech Connect

    Tohmon, G.; Sato, H.; Ohya, J.; Uno, T.

    1997-05-01

    We demonstrate and analyze an upconversion blue fiber laser pumped by two wavelengths. Lasing at 0.48 {mu}m with very low pump threshold power is obtained from a Tm-doped fluorozirconate fiber that is counterpropagating pumped by 1.21- and 0.649-{mu}m light. We employed a rate-equation analysis using parameters obtained by fitting to the experimental data to predict the 0.48-{mu}m output characteristics as a function of fiber length and output reflectivity. {copyright} 1997 Optical Society of America

  8. Laser Processing of Carbon Fiber Reinforced Plastics - Release of Carbon Fiber Segments During Short-pulsed Laser Processing of CFRP

    NASA Astrophysics Data System (ADS)

    Walter, Juergen; Brodesser, Alexander; Hustedt, Michael; Bluemel, Sven; Jaeschke, Peter; Kaierle, Stefan

    Cutting and ablation using short-pulsed laser radiation are promising technologies to produce or repair CFRP components with outstanding mechanical properties e.g. for automotive and aircraft industry. Using sophisticated laser processing strategies and avoiding excessive heating of the workpiece, a high processing quality can be achieved. However, the interaction of laser radiation and composite material causes a notable release of hazardous substances from the process zone, amongst others carbon fiber segments or fibrous particles. In this work, amounts and geometries of the released fiber segments are analyzed and discussed in terms of their hazardous potential. Moreover, it is investigated to what extent gaseous organic process emissions are adsorbed at the fiber segments, similar to an adsorption of volatile organic compounds at activated carbon, which is typically used as filter material.

  9. 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.

  10. 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.

  11. Fiber Optically Coupled Eyesafe Laser Threat Warning System

    DTIC Science & Technology

    2000-05-11

    WARNING SYSTEM 11 MAY 2000 MSS SPECIALTY GROUP ON INFRARED COUNTERMEASURES NAVAL POSTGRADUATE SCHOOL, MONTEREY, CA PRESENTED BY: DR. AL TORRES...A Dates Covered (from... to) - Title and Subtitle Fiber Optically Coupled Eyesafe Laser Threat Warning System Contract Number Grant Number... WARNING SYSTEM (ESLTWS) PHASE II SBIR PROGRAM • CONCEPT: - TO DEVELOP A UNIQUE AND NOVEL EYE SAFE LASER THREAT WARNING RECEIVER SYSTEM. MUST BE

  12. 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.

  13. Erbium-doped photonic crystal fiber chaotic laser

    NASA Astrophysics Data System (ADS)

    Martín, Juan C.; Used, Javier; Sánchez-Martín, José A.; Berdejo, Víctor; Vallés, Juan A.; Álvarez, José M.; Rebolledo, Miguel A.

    2011-09-01

    An erbium-doped photonic crystal fiber laser has been designed, constructed and characterized in order to examine the feasibility of this kind of devices for secure communications applications based on two identical chaotic lasers. Inclusion of a tailored photonic crystal fiber as active medium improves considerably the security of the device because it allows customization of the mode transversal profile, very influential on the laser dynamics and virtually impossible to be cloned by undesired listeners. The laser design has been facilitated by the combination of characterization procedures and models developed by us, which allow prediction of the most suitable laser features (losses, length of active fiber, etc.) to a given purpose (in our case, a laser that emits chaotically for a wide assortment of pump modulation conditions). The chaotic signals obtained have been characterized by means of topological analysis techniques. The underlying chaotic attractors found present topological structures belonging to classes of which very scarce experimental results have been reported. This fact is interesting from the point of view of the study of nonlinear systems and, besides, it is promising for secure communications: the stranger the signals, the more difficult for an eavesdropper to synthesize another system with similar dynamics.

  14. Hot bending with a fiber coupled solid state laser

    NASA Astrophysics Data System (ADS)

    Bammer, F.; Schumi, T.; Schuöcker, D.

    2010-09-01

    For bending of brittle materials it is necessary to heat up the forming zone. This can be done with a fiber coupled solid state laser, whose beam is evenly distributed on the bending line with a beam splitter installed in the lower tool (die) of a bending press. With polarization optics the laser beam is divided there into partial beams that are evenly distributed on the bending line with lenses and prisms. A setup for a bending length of 200mm heated by a fiber-coupled 3kW Nd:YAG-laser shows the feasibility of the concept. Successful operation was shown for the Mg-alloy AZ31, which breaks during forming at room temperature, but can be well formed at temperatures in the range of 200-300°C. Other materials benefiting from this method are Ti-alloys, high-strength-Al-alloys, and high-strength-steels. Typical heating times are in the range of up to 5s and much of the heat input is generated during the bending operation where the laser continues to work. Laser Assisted Bending with a fiber coupled solid state laser is a straightforward way to perform the bending of brittle materials in a process as simple as cold bending.

  15. 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.

  16. 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.

  17. Erbium-doped CW and Q-switched fiber ring laser with fiber grating Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Wang, Anting; Ming, Hai; Xie, Jianping; Xu, Lixin; Huang, Wencai; Lv, Liang; Chen, Xiyao; Li, Feng; Wu, Yunxia; Xing, Meishu

    2003-01-01

    The band-pass characteristic of fiber grating Michelson interferometer is analyzed, which acts as both band-pass filter and Q-switch. An erbium-doped fiber ring laser based on fiber grating Michelson interferometer is implemented for producing single longitudinal mode CW operation with 5 MHz spectral linewidth and up to 6 mW output power. In Q-switched operation, stable fiber laser output pulses with repetition rate of 800 Hz, pulse width of 0.6 ?s, average power of 1.8 mW and peak power of 3.4 W are demonstrated. The peak power and average power of the Q-switched pulses are varied with the repetitionrate.

  18. Intensity-demodulated fiber-ring laser sensor system for acoustic emission detection.

    PubMed

    Han, Ming; Liu, Tongqing; Hu, Lingling; Zhang, Qi

    2013-12-02

    We theoretically and experimentally demonstrate a fiber-optic ultrasonic sensor system based on a fiber-ring laser whose cavity consisting of a regular fiber Bragg grating (FBG) and a tunable optical band-pass filter (TOBPF). The FBG is the sensing element and the TOBPF is used to set the lasing wavelength at a point on the spectral slope of the FBG. The ultrasonic signal is detected by the variations of the laser output intensity in response to the cold-cavity loss modulations from the ultrasonically-induced FBG spectral shift. The system demonstrated here has a simple structure and low cost, making it attractive for acoustic emission detection in structure health monitoring.

  19. Linearly-polarized Yb-doped fiber laser based on 45-degree fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Fu, Shenggui; Liu, Xiaojuan; Guo, Liping; Ge, Xiaolu; Wei, Gongxiang

    2012-11-01

    In the paper, a 45 degree TFBG was fabricated in photosensitive fiber successfully using phase mask technique. The polarization-dependent loss characteristic of the TFBG was experimentally researched in the paper using a special measurement system. The measurement results showed that the 45 degree TFBG could act as a polarization possession element. Based on the 45 degree TFBG, a linearly-polarized Yb-doped fiber laser was demonstrated. The polarization-extinction ratio of the output laser is about 30 dB. The output power was about 13 mW with the pump power of 100 mW. The central wavelength of the laser is 1064nm and the wavelength bandwidth was about 0.7nm. Being a polarization device, the TFBG has the advantages of in-fiber, compact, good polarization capability and low price.

  20. 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.

  1. Characterization of holmium fibers with various concentrations for fiber laser applications around 2.1 μm

    NASA Astrophysics Data System (ADS)

    Aubrecht, Jan; Peterka, Pavel; Honzatko, Pavel; Baravets, Yauhen; Jelinek, Michal; Kubecek, Vaclav; Pawliszewska, Maria; Sotor, Jaroslaw; Sobon, Grzegorz; Abramski, Krzysztof M.; Kasik, Ivan

    2016-04-01

    In this work, we present experimental results of characterization of the developed holmium-doped silica-based optical fibers with holmium ions concentrations in the range from 1000 to 10000 ppm. The fibers were fabricated by the modified chemical vapor deposition and solution doping method. They were characterized in terms of their spectral attenuation, refractive index profile, and especially performance in fiber laser. Simultaneously, two different fiber laser setups were tested. In the first one, holmium-doped fiber in Fabry-Perot configuration was pumping by in house developed thulium-doped fiber laser in ring arrangement. In the second one, bulk-optic pump-coupling configuration, consisted of a commercially available thulium fiber laser emitting at 1940 nm and system of lenses and mirrors was used. We have focused on comparison of laser output powers, slope efficiencies, and laser thresholds for individual holmiumdoped fiber in these different laser arrangements. Finally, the application of the developed fiber in subpicosecond fiber laser with graphene-based saturable absorber for mode-locking operation was investigated.

  2. Single-longitudinal-mode DBR fiber laser based on the self-made photosensitive Er-doped fiber

    NASA Astrophysics Data System (ADS)

    Ren, Wen-hua; Zheng, Jing-jing; Wang, Yan-hua; Tao, Pei-lin; Tan, Zhong-wei; Jian, Shui-sheng

    2008-12-01

    Two fiber Bragg gratings with ~35mm spatial interval are written in the self-made photosensitive Erbium-doped fiber (PEDF) to form a fiber Bragg grating Fabry-Perot (FBG F-P) cavity. A distributed Bragg reflector (DBR) fiber laser is built up based on the FBG F-P cavity. 1.8mW laser output is achieved with 63mW pump power. By calculating the mode-spacing using the effective length of the FBG F-P cavity, the output of the DBR fiber laser is proved to be singlelongitudinal- mode (SLM).

  3. All-fiber passively mode-locked femtosecond laser using a 45º-tilted fiber grating polarization element.

    PubMed

    Mou, Chengbo; Wang, Hua; Bale, Brandon G; Zhou, Kaiming; Zhang, Lin; Bennion, Ian

    2010-08-30

    We report on the demonstration of an all-fiber femtosecond erbium doped fiber laser passively mode-locked using a 45º tilted fiber grating as an in-fiber polarizer in the laser cavity. The laser generates 600 fs pulses with output pulse energies ~1 nJ. Since the 45° tilted grating has a broad polarization response, the laser output has shown a tunabilty in wavelength from 1548 nm to 1562 nm by simply adjusting the polarization controllers in the cavity.

  4. Laser-drilled free-form silica fiber preforms for microstructured optical fibers

    NASA Astrophysics Data System (ADS)

    Becker, Martin; Werner, Marcel; Fitzau, Oliver; Esser, Dominik; Kobelke, Jens; Lorenz, Adrian; Schwuchow, Anka; Rothhardt, Manfred; Schuster, Kay; Hoffmann, Dieter; Bartelt, Hartmut

    2013-10-01

    We describe a laser drilling technology suitable for structuring solid glass preforms for microstructured optical fibers. This technology offers the possibility to prepare complex preform designs that cannot be easily managed by the stack-and-draw technology. As a proof of concept, we present a four-ring hexagonal hole structure drilled in a silica rod over a length of 80 mm. A fiber drawn from such a preform has been analyzed to demonstrate the feasibility of this concept.

  5. Multiwavelength generation in a random distributed feedback fiber laser using an all fiber Lyot filter.

    PubMed

    Sugavanam, S; Yan, Z; Kamynin, V; Kurkov, A S; Zhang, L; Churkin, D V

    2014-02-10

    Multiwavelength lasing in the random distributed feedback fiber laser is demonstrated by employing an all fiber Lyot filter. Stable multiwavelength generation is obtained, with each line exhibiting sub-nanometer line-widths. A flat power distribution over multiple lines is obtained, which indicates that the power between lines is redistributed in nonlinear mixing processes. The multiwavelength generation is observed both in first and second Stokes waves.

  6. All-fiber tunable filter and laser based on two-mode fiber.

    PubMed

    Yun, S H; Hwang, I K; Kim, B Y

    1996-01-01

    We demonstrate an all-fiber acousto-optic tunable filter based on two-spatial-mode coupling, with improved ruggedness and efficiency, by using a new acoustic-transducer design. We use a rigorous modeling of the flexural acoustic wave to analyze the mode coupling with better accuracy. Using the acousto-optic tunable filter, we demonstrate a novel all-fiber tunable laser with a tuning range of more than 20 nm and a linewidth of 0.2 nm.

  7. Ultrafast, stretched-pulse thulium-doped fiber laser with a fiber-based dispersion management.

    PubMed

    Wienke, Andreas; Haxsen, Frithjof; Wandt, Dieter; Morgner, Uwe; Neumann, Jörg; Kracht, Dietmar

    2012-07-01

    An ultrafast thulium-doped fiber laser with stretched-pulse operation has been realized and investigated. The passively mode-locked oscillator emitted 119 fs pulses at a peak wavelength of 1912 nm. A normal-dispersion fiber with a high numerical aperture and small core was used for intracavity dispersion management and external compression. Numerical simulations were performed and are in good agreement with the experimental results.

  8. High energy similariton fiber laser using chirally-coupled-core fiber

    PubMed Central

    Lefrancois, Simon; Liu, Chi-Hung; Stock, Michelle L.; Sosnowski, Thomas S.; Galvanauskas, Almantas; Wise, Frank W.

    2013-01-01

    We present a high energy amplifier similariton laser based on chirally-coupled core fiber. Chirped pulse energies up to 61 nJ at 3.3 W average power are obtained with effectively singlemode output. The pulses can be compressed with a simple grating compressor to durations below 90 fs. We demonstrate for the first time a fused pump-signal combiner to confirm the integration potential of chirally-coupled core fibers. PMID:23282832

  9. 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.

  10. 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.

  11. Rogue waves in a normal-dispersion fiber laser.

    PubMed

    Liu, Zhanwei; Zhang, Shumin; Wise, F W

    2015-04-01

    Experimental evidence of rogue-wave formation in a normal-dispersion ytterbium fiber laser is reported. Spectral filtering is a primary component of pulse-shaping in normal-dispersion lasers, and we find that the choice of filter dramatically influences the distribution of noise-pulse energies produced by these lasers. With an interference filter in the cavity, non-Gaussian distributions with pulses as large as 6 times the significant wave height are observed. These correspond to pulse energies as high as ∼50  nJ. To our knowledge, the results presented are not accounted for by existing theoretical models of rogue-wave formation.

  12. 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.

  13. Synchronization and symmetry breaking in mutually coupled fiber lasers.

    PubMed

    Rogers-Dakin, Elizabeth A; García-Ojalvo, Jordi; DeShazer, David J; Roy, Rajarshi

    2006-04-01

    We experimentally study the synchronization and the emergence of leader-follower dynamics in two time-delayed mutually coupled fiber ring lasers. We utilize spatiotemporal representations of time series to establish the roles of leader and follower in the synchronized dynamics.

  14. Synchronization and symmetry breaking in mutually coupled fiber lasers

    NASA Astrophysics Data System (ADS)

    Rogers-Dakin, Elizabeth A.; García-Ojalvo, Jordi; Deshazer, David J.; Roy, Rajarshi

    2006-04-01

    We experimentally study the synchronization and the emergence of leader-follower dynamics in two time-delayed mutually coupled fiber ring lasers. We utilize spatiotemporal representations of time series to establish the roles of leader and follower in the synchronized dynamics.

  15. Laser Treatment, Bonding Potential Road to Success for Carbon Fiber

    ScienceCinema

    Sabau, Adrian

    2016-07-12

    Joining carbon fiber composites and aluminum for lightweight cars and other multi-material high-end products could become less expensive and the joints more robust because of a new method that harnesses a laser’s power and precision.

  16. All-fiber broad-range self-sweeping Yb-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Lobach, Ivan A.; Kablukov, Sergey A.; Podivilov, Evgeniy V.; Babin, Sergey A.

    2012-02-01

    The effect of broad-range self-sweeping in Yb-doped fiber laser has been demonstrated experimentally for the first time. The self-sweeping effect is observed in an all-fiber laser configuration with a double-clad Yb-doped fiber and a cavity formed by a broad-band fiber loop mirror and Fresnel reflection from one cleaved end. The sweep range is limited by the width of the broad-band reflector and reaches up to 16nm. It is found that the self-sweeping effect is related to selfpulsations. So the sweep rate is increased with an increase in pump power and is decreased with increasing cavity length. RF and optical spectra (linewidth is measured to be not more than 100 MHz) show that during the evolution of a single pulse a small number of longitudinal modes take a part in lasing. Based on these results we propose a model describing dynamics of the laser frequency. The model is based on the spatial hole burning effect and the gain saturation in Yb laser transition, and takes into account self-pulsations of the laser. Theoretical estimation for pulse to pulse change of lasing frequency is in good agreement with experimental data.

  17. 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.

  18. 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

    2016-07-26

    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.

  19. 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

  20. 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.

  1. Pulsed blue laser source based on frequency quadrupling of a thulium fiber laser

    NASA Astrophysics Data System (ADS)

    Honea, Eric; Savage-Leuchs, Matthias; Bowers, Mark S.; Yilmaz, Tolga; Mead, Roy

    2013-03-01

    We describe a pulsed blue (485 nm) laser source based on frequency quadrupling a pulsed Tm fiber laser. Up to 1.2 W at 485 nm was generated with an M2 of 1.3. At 10 kHz pulse repetition frequency, the output pulse at 485 nm was 65 ns FWHM resulting in an estimated peak power of 1.8 kW. We anticipate further improvements in power scaling with higher power Tm fiber lasers and improved conversion efficiency to the blue with optimized AR coatings and nonlinear optical crystals.

  2. All-fiber mode-locked nanosecond laser employing intracavity chirped fiber gratings.

    PubMed

    Wang, Hushan; Wang, Yishan; Zhao, Wei; Zhang, Wei; Zhang, Ting; Hu, Xiaohong; Yang, Zhi; Liu, Hongjun; Duan, Kailiang; Liu, Xuemin; Li, Cheng; Shen, Deyuan; Sui, Zhan; Liu, Bin

    2010-03-29

    We demonstrate that nanosecond pulses are generated directly from an all-fiber mode-locked ytterbium-doped fiber laser. A pair of Chirped Fiber Gratings (CFGs) with different sign of dispersion is employed for intracavity dispersion management. Self-starting stabilized mode-locking operation is achieved by nonlinear polarization evolution (NPE). The 1.27 ns pulses are obtained after one CFG with large positive dispersion. The pulse energy is up to 15 nJ at a repetition rate of 3.48 MHz.

  3. Understanding the fiber tip thermal runaway present in 3 µm fluoride glass fiber lasers.

    PubMed

    Caron, Nicolas; Bernier, Martin; Faucher, Dominic; Vallée, Réal

    2012-09-24

    When the tip of a fluoride glass fiber is exposed to ambient air, water vapor reacts with the glass constituents, increasing the OH contaminants at the surface. These OH impurities then diffuse inside the glass according to Fick's laws. Laser radiation at around 3 µm is strongly absorbed by the OH contaminants, causing local heating of the fiber tip resulting in an increase of the diffusion process which ultimately leads to fiber tip destruction. We accurately model this phenomenon by combining the diffusion theory with a basic thermal equation. Experimental measurements are in agreement with the model predictions for a good range of operating conditions.

  4. UV-laser-inscribed fiber Bragg gratings in photonic crystal fibers and sensing applications

    NASA Astrophysics Data System (ADS)

    Wang, Yiping; Bartelt, Hartmut; Ecke, Wolfgang; Willsch, Reinhardt; Kobelke, Jens

    2011-11-01

    We report about fiber Bragg gratings (FBGs) inscribed in two different types of small-core Ge-doped photonic crystal fibers with a UV laser. Sensing applications of the FBGs were systematically investigated by means of demonstrating the responses of Bragg wavelengths to temperature, strain, bending, and transverse-loading. The Bragg wavelength of the FBGs shifts toward longer wavelengths with increasing temperature, tensile strain, and transverse-loading. Moreover, the bending and transverse-loading properties of the FBGs are sensitive to the fiber orientations. The reasonable analyses for these sensing properties also are presented.

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  6. Dual wavelength erbium-doped fiber laser using a tapered fiber

    NASA Astrophysics Data System (ADS)

    Harun, S. W.; Lim, K. S.; Jasim, A. A.; Ahmad, H.

    2010-12-01

    A tapered fiber is fabricated by heating and stretching a piece of optical fiber after the polymer protective cladding has been removed. An equidistant comb-like transmission spectrum, with a spacing of 1.6 nm and an extinction ratio of more than 5 dB, was obtained by the tapered fiber due to the multibeam interferences of the cladding modes. The tapered fiber was applied in a ring erbium-doped fiber laser (EDFL) to generate dual-wavelength lasing oscillations. The EDFL operates at wavelengths of 1557.0 nm and 1558.6 nm with a stable peak power and a signal-to-noise ratio of more than 40 dB.

  7. Noncontact laser fiber delivery system for endoscopic medical applications

    NASA Astrophysics Data System (ADS)

    Denisov, Nikolay A.; Griffin, Stephen E.

    1999-02-01

    The objective of the study was to design and to investigate laser fiber delivery system for treatment of obstructed human internal tubular organs using endoscopic techniques. This system eliminates the main disadvantages of both applied contact and non-contact probes, namely surface contamination with concomitant hydrothermal probe deterioration and large beam divergence with poor energy density, respectively. Proposed silica or sapphire probes produce quasi-collimated beam with specific outside diameter and power distribution. To provide comparative analysis of laser delivery systems' optical properties with non-contact endoscopic probes 'steady beam distance' (SBD) and 'steady beam ratio' (SBR) coefficients are proposed. The calculation results are presented in the form of the plots of the SBR - coefficients and SBDs for a 2.0 mm specific outside beam diameter versus laser wavelength, delivery fiber core diameter and its numerical aperture for both probe material. Additionally, the cross power distributions along the SBD were studied. Results obtained could provide a useful tool to designers of non-contact fiber delivery systems intended for a variety of medical applications, including endoscopic surgery with cw or pulse laser tissue irradiation, skin de-epithelialization, laser-induced fluorescence and photodynamic therapy.

  8. Single-mode fiber laser based on core-cladding mode conversion.

    PubMed

    Suzuki, Shigeru; Schülzgen, Axel; Peyghambarian, N

    2008-02-15

    A single-mode fiber laser based on an intracavity core-cladding mode conversion is demonstrated. The fiber laser consists of an Er-doped active fiber and two fiber Bragg gratings. One Bragg grating is a core-cladding mode converter, and the other Bragg grating is a narrowband high reflector that selects the lasing wavelength. Coupling a single core mode and a single cladding mode by the grating mode converter, the laser operates as a hybrid single-mode laser. This approach for designing a laser cavity provides a much larger mode area than conventional large-mode-area step-index fibers.

  9. Random fiber laser directly pumped by a high-power laser diode.

    PubMed

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

    2013-09-01

    A random lasing based on Rayleigh scattering (RS) in a passive fiber directly pumped by a high-power laser diode (LD) has been demonstrated. Owing to the RS-based random distributed feedback (RDFB) the low-quality LD beam (938 nm) is converted into the high-quality laser output (980 nm). Because of the relatively low excess above the threshold with the available LD, the RDFB laser output is not stationary and limited in power at the 0.5 W level. In the used gradient-index fiber, the output beam has 4.5 lower divergence as compared with the pump beam thus demonstrating a new way for development of high-power fiber lasers with high-quality output.

  10. 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.

  11. 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.

  12. High-Energy Passive Mode-Locking of Fiber Lasers

    PubMed Central

    Ding, Edwin; Renninger, William H.; Wise, Frank W.; Grelu, Philippe; Shlizerman, Eli; Kutz, J. Nathan

    2012-01-01

    Mode-locking refers to the generation of ultrashort optical pulses in laser systems. A comprehensive study of achieving high-energy pulses in a ring cavity fiber laser that is passively mode-locked by a series of waveplates and a polarizer is presented in this paper. Specifically, it is shown that the multipulsing instability can be circumvented in favor of bifurcating to higher-energy single pulses by appropriately adjusting the group velocity dispersion in the fiber and the waveplate/polarizer settings in the saturable absorber. The findings may be used as practical guidelines for designing high-power lasers since the theoretical model relates directly to the experimental settings. PMID:22866059

  13. Tungsten diselenide Q-switched erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Chen, Bohua; Zhang, Xiaoyan; Guo, Chaoshi; Wu, Kan; Chen, Jianping; Wang, Jun

    2016-08-01

    We report a tungsten diselenide (WSe2) polyvinyl alcohol (PVA)-based, saturable absorber and related experiment results of a Q-switched fiber laser. WSe2-PVA film is synthesized by liquid phase exfoliation method, and its saturable absorption is measured via a nonlinear transmission experiment. The result shows that WSe2-PVA saturable absorber has a modulation depth of 3.5%, which means it has potential for generating an ultrafast pulse laser. We apply this absorber into a ring-cavity erbium-doped fiber laser and obtain Q-switched pulses under appropriate pump power. Our work demonstrates the reliable nonlinear optical characteristics of WSe2 and the feasibility for this two-dimensional material to be applied in the field of nonlinear optics.

  14. 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.

  15. Dynamics of ultra-long Brillouin fiber laser

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  16. 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

    2016-07-15

    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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Fiber optic confocal laser Doppler velocimeter using an all-fiber laser source for high resolution measurements.

    PubMed

    Sharma, Utkarsh; Chen, Gang; Kang, Jin; Ilev, Ilko; Waynant, Ronald

    2005-08-08

    We demonstrate and analyze a novel fiber optic confocal laser Doppler velocimeter using an ultra-narrow linewidth all-fiber laser source centered at around 1550 nm (eye-safe region). The narrow spectral linewidth of the fiber laser (<10 kHz) is used to achieve an extremely high velocity resolution (~0.0075 m/s), which is an order of magnitude better as compared to the commonly used semiconductor diode lasers or He-Ne lasers based systems. The directional optical circulator based design used in our system is much simpler to implement and is power conserving compared to the conventional Michelson interferometer based designs. We perform Gaussian beam propagation analysis by using the ABCD law to study the performance of the confocal design. The analysis is in good accord with our experimental results. The confocal design is capable of providing ultrahigh spatial resolution (~5microm, in both lateral and longitudinal directions) for high-precision velocity distribution measurement applications.

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

    DTIC Science & Technology

    2011-09-01

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

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  6. 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.

  7. 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

  8. Random distributed feedback Raman fiber laser with polarized pumping

    NASA Astrophysics Data System (ADS)

    Wu, H.; Wang, Z. N.; Churkin, D. V.; Vatnik, I. D.; Fan, M. Q.; Rao, Y. J.

    2015-01-01

    In this letter, the polarization properties of a random fiber laser operating via Raman gain and random distributed feedback owing to Rayleigh scattering are investigated for the first time. Using polarized pump, the partially polarized generation is obtained with a generation spectrum exhibiting discrete narrow spectral features contrary to the smooth spectrum observed for the depolarized pump. The threshold, output power, degree of polarization and the state of polarization (SOP) of the lasing can be significantly influenced by the SOP of the pump. Fine narrow spectral components are also sensitive to the SOP of the pump wave. Furthermore, we found that random lasing’s longitudinal power distributions are different in the case of polarized and depolarized pumping that results in considerable reduction of the generation slope efficiency for the polarized radiation. Our results indicate that polarization effects play an important role on the performance of the random fiber laser. This work improves the understanding of the physics of random lasing in fibers and makes a step forward towards the establishment of the vector model of random fiber lasers.

  9. 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.

  10. 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.

  11. Latest development of high-power fiber lasers in SPI

    NASA Astrophysics Data System (ADS)

    Norman, Stephen; Zervas, Mikhail N.; Appleyard, Andrew; Durkin, Michael K.; Horley, Ray; Varnham, Malcolm P.; Nilsson, Johan; Jeong, Yoonchan

    2004-06-01

    High Power Fiber Lasers (HPFLs) and High Power Fiber Amplifiers (HPFAs) promise a number of benefits in terms of their high optical efficiency, degree of integration, beam quality, reliability, spatial compactness and thermal management. These benefits are driving the rapid adoption of HPFLs in an increasingly wide range of applications and power levels ranging from a few Watts, in for example analytical applications, to high-power >1kW materials processing (machining and welding) applications. This paper describes SPI"s innovative technologies, HPFL products and their performance capabilities. The paper highlights key aspects of the design basis and provides an overview of the applications space in both the industrial and aerospace domains. Single-fiber CW lasers delivering 1kW output power at 1080nm have been demonstrated and are being commercialized for aerospace and industrial applications with wall-plug efficiencies in the range 20 to 25%, and with beam parameter products in the range 0.5 to 100 mm.mrad (corresponding to M2 = 1.5 to 300) tailored to application requirements. At power levels in the 1 - 200 W range, SPI"s proprietary cladding-pumping technology, GTWaveTM, has been employed to produce completely fiber-integrated systems using single-emitter broad-stripe multimode pump diodes. This modular construction enables an agile and flexible approach to the configuration of a range of fiber laser / amplifier systems for operation in the 1080nm and 1550nm wavelength ranges. Reliability modeling is applied to determine Systems martins such that performance specifications are robustly met throughout the designed product lifetime. An extensive Qualification and Reliability-proving programme is underway to qualify the technology building blocks that are utilized for the fiber laser cavity, pump modules, pump-driver systems and thermo-mechanical management. In addition to the CW products, pulsed fiber lasers with pulse energies exceeding 1mJ with peak pulse

  12. 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.

  13. 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.

  14. Sub-100 fs mode-locked erbium-doped fiber laser using a 45°-tilted fiber grating.

    PubMed

    Zhang, Zuxing; Mou, Chengbo; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin; Turitsyn, Sergei

    2013-11-18

    We demonstrate generation of sub-100 fs pulses at 1.5 µm in a mode-locked erbium-doped fiber laser using a 45°-tilted fiber grating element. The laser features a genuine all-fiber configuration. Based on the unique polarization properties of the 45°-tilted fiber grating, we managed to produce sub-100 fs laser pulses through proper dispersion management. To the best of our knowledge, this is the shortest pulse generated from mode-locked lasers with fiber gratings. The output pulse has an average power of 8 mW, with a repetition rate of 47.8 MHz and pulse energy of 1.68 nJ. The performance of laser also matches well the theoretical simulations.

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

    PubMed

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

    2008-10-13

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

  16. Towards high-quality optical ceramic YAG fibers for high-energy laser (HEL) applications

    NASA Astrophysics Data System (ADS)

    Lee, HeeDong; Keller, Kristin; Sirn, Brian

    2012-06-01

    There is a critical demand for high quality, transparent ceramic YAG fibers for high powered fiber lasers. The production of laser quality ceramic fibers hinges on advanced ceramic processing technology, along with the availability of highly sinterable powder with high phase and chemical purity. These two fundamental technologies have been successfully developed at UES. Nd (1.1 a/o) and Yb (1.0 a/o)-doped yttrium aluminum garnet (YAG) fibers with high optical quality were produced by combining UES's tailored powders with advanced consolidation processes including fiber extrusion and vacuum sintering. The as-sintered and as-annealed fibers, approximately 30 microns in diameter, appeared transparent and successfully transmitted laser beams; further development will allow for the production of doped ceramic YAG fiber lasers for advanced high power and high energy fiber laser systems.

  17. Soliton generation from an actively mode-locked fiber laser incorporating an electro-optic fiber modulator.

    PubMed

    Malmström, Mikael; Margulis, Walter; Tarasenko, Oleksandr; Pasiskevicius, Valdas; Laurell, Fredrik

    2012-01-30

    This work demonstrates an actively mode-locked fiber laser operating in soliton regime and employing an all-fiber electro-optic modulator. Nonlinear polarization rotation is utilized for femtosecond pulse generation. Stable operation of the all-fiber ring laser is readily achieved at a fundamental repetition rate of 2.6 MHz and produces 460 fs pulses with a spectral bandwidth of 5.3 nm.

  18. 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

  19. Hollow light guide and optical fiber for UV laser transmission

    NASA Astrophysics Data System (ADS)

    Kubo, Uichi; Hashishin, Yuichi; Nakano, Hitoshi; Tanaka, Hiroyuki

    1997-12-01

    The applications of ultraviolet lasers in medicine and surgery are expected to produce new therapies since UV laser is strongly absorbed by lipids, proteins and nucleic acids. The suitable tools for the UV laser power delivery, however, have not been developed yet. In an effort to make efficient delivery of UV laser, we have proposed hollow light guide which consists of an aluminum-phosphor bronze reflector and a teflon E-type rail spacer. The delivery characteristics of the hollow light guide have been investigated using the ArF and KrF excimer lasers. In case of the KrF laser, the transmittance and delivery energy reached 77%/m and 110 mJ/pulse, respectively. In the ArF laser, the transmittance and delivery energy were obtained to be 56%/m and 40 mJ/pulse, respectively. It is known that 193 nm radiation by the ArF laser are absorbed by the air. Thus, the ArF laser beam delivery were examined in the helium gas. The transmittance and the delivery energy were obtained to be 72%/m and 50 mJ/pulse using helium-filled hollow light guide, which were greatly improved for comparison with the case of the air. We have also tried the quartz fiber with OH ion doped core. The effects of a lightly doped core with Cl and a clad with B-F on the laser transmittance have been investigated. In these result, the Cl was not good core dopant. The B and F were useful clad dopants for the excimer laser transmission.

  20. Hollow light guide and optical fiber for UV laser transmission

    NASA Astrophysics Data System (ADS)

    Kubo, Uichi; Hashishin, Yuichi; Nakano, Hitoshi; Tanaka, Hiroyuki

    1998-01-01

    The applications of ultraviolet lasers in medicine and surgery are expected to produce new therapies since UV laser is strongly absorbed by lipids, proteins and nucleic acids. The suitable tools for the UV laser power delivery, however, have not been developed yet. In an effort to make efficient delivery of UV laser, we have proposed hollow light guide which consists of an aluminum-phosphor bronze reflector and a teflon E-type rail spacer. The delivery characteristics of the hollow light guide have been investigated using the ArF and KrF excimer lasers. In case of the KrF laser, the transmittance and delivery energy reached 77%/m and 110 mJ/pulse, respectively. In the ArF laser, the transmittance and delivery energy were obtained to be 56%/m and 40 mJ/pulse, respectively. It is known that 193 nm radiation by the ArF laser are absorbed by the air. Thus, the ArF laser beam delivery were examined in the helium gas. The transmittance and the delivery energy were obtained to be 72%/m and 50 mJ/pulse using helium-filled hollow light guide, which were greatly improved for comparison with the case of the air. We have also tried the quartz fiber with OH ion doped core. The effects of a lightly doped core with Cl and a clad with B-F on the laser transmittance have been investigated. In these result, the Cl was not good core dopant. The B and F were useful clad dopants for the excimer laser transmission.

  1. Stable multi-wavelength fiber lasers for temperature measurements using an optical loop mirror.

    PubMed

    Diaz, Silvia; Socorro, Abian Bentor; Martínez Manuel, Rodolfo; Fernandez, Ruben; Monasterio, Ioseba

    2016-10-10

    In this work, two novel stable multi-wavelength fiber laser configurations are proposed and demonstrated by using a spool of a single-mode fiber as an optical loop mirror and one or two fiber ring cavities, respectively. The lasers are comprised of fiber Bragg grating reflectors as the oscillation wavelength selecting filters. The influence of the length of the spool of fiber on the laser stability both in terms of wavelength and laser output power was investigated. An application for temperature measurement is also shown.

  2. Endometrial ablation using SideFire laser fiber

    NASA Astrophysics Data System (ADS)

    Everett, Royice B.

    1996-05-01

    The first successful report using the neodymium:yttrium-aluminum-garnet (Nd:YAG) Laser to control hypermenorrhea was reported in 1981. Variations on the treatment technique have been attempted to improve the amenorrhea rate. Reports using the Nd:YAG laser with the blanching or non-touch technique seem to result in a better outcome and higher rate of total amenorrhea than using the dragging technique. Due to the report of improved rates of amenorrhea when using the blanching technique and the Nd:YAG laser, a fiber was developed to direct the laser energy at right angles to the axis of the fiber, therefore allowing a total treatment of the entire uterus in a perpendicular fashion. The theoretic benefit of this would be a more complete and predictable destruction of the endometrial lining, avoiding fluid overload by coagulating and sealing of the vessels and lymphatic. After a follow-up of 12 to 36 months, 56 of the 60 patients (93%) who underwent complete endometrial ablation with the SideFireTM technique had excellent results. Total absolute amenorrhea resulted in 50 patients (83%). Contrary to earlier reports, using the rollerball electrode, this procedure technique resulted in no decrease in results in younger patients. In conclusion, this seems to be a reasonable alternative which offers improved results when compared to previously available methods using electrosurgery or the Nd:YAG laser without the use of the SideFireTM device.

  3. 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.

  4. Power scaling of high-efficiency 1.5 μm cascaded Raman fiber lasers.

    PubMed

    Supradeepa, V R; Nicholson, Jeffrey W

    2013-07-15

    High-power fiber lasers operating at the 1.5 μm wavelength region have attractive features, such as eye safety and atmospheric transparency, and cascaded Raman fiber lasers offer a convenient method to obtain high-power sources at these wavelengths. A limitation to power scaling, however, has been the lower conversion efficiency of these lasers. We recently introduced a high-efficiency architecture for high-power cascaded Raman fiber lasers applicable for 1.5 μm fiber lasers. Here we demonstrate further power scaling using this new architecture. Using numerical simulations, we identify the ideal operating conditions for the new architecture. We demonstrate a high-efficiency 1480 nm cascaded Raman fiber laser with an output power of 301 W, comparable to record power levels achieved with rare-earth-doped fiber lasers in the 1.5 μm wavelength region.

  5. 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).

  6. Actively mode-locked fiber laser using acousto-optic modulator

    NASA Astrophysics Data System (ADS)

    Nikodem, Michal P.; Sergeant, Hendrik; Kaczmarek, Pawel; Abramski, Krzysztof M.

    2008-12-01

    In recent years we have observed growing interest in mode-locked fiber lasers. Development of erbium doped fiber (EDF) amplifiers and WDM technique made 3rd telecommunication window extremely interesting region for ultrafast optics. The main advantages of fiber lasers i.e. narrow linewidth and wide gain bandwidth make them very attractive sources in various applications. In this paper we present an actively mode-locked erbium doped fiber ring laser. Modelocking is obtained using an acousto-optic modulator (AOM) coupled into the laser cavity. The impact of different parameters (e.g. light polarization, modulation frequency) is investigated. We study mechanisms of controlling the wavelength of the laser.

  7. 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.

  8. Flexible pulses from carbon nanotubes mode-locked fiber laser

    NASA Astrophysics Data System (ADS)

    Yang, Ling-Zhen; Yang, Yi; Wang, Juan-Fen

    2016-12-01

    We demonstrate a flexible erbium-doped pulsed fiber laser which achieves the wavelength and pulse width tuning by adjusting an intracavity filter. The intracavity filter is flexible to achieve any of the different wavelengths and bandwidths in the tuning range. The wavelength and width of pulse can be tuned in a range of ˜ 20 nm and from ˜ 0.8 ps to 87 ps, respectively. The flexible pulsed fiber laser can be accurately controlled, which is insensitive to environmental disturbance. Project supported by the National Natural Science Foundation of China (Grant No. 61575137) and the Program on Social Development by Department of Science and Technology of Shanxi Province, China (Grant No. 20140313023-3).

  9. Fiber laser hydrophone for low frequency signal detection

    NASA Astrophysics Data System (ADS)

    Zhang, Wentao; Li, Fang; Liu, Yuliang

    2012-02-01

    A fiber laser hydrophone (FLH) based on a flat diaphragm and an L shaped lever is presented. This hydrophone uses an L shaped lever to transfer the acoustic pressure induced defection of the flat diaphragm to the axial elongation of the fiber laser. The curve where the L shaped lever contacts the diaphragm is a segment of an Archimedes spiral, which is used to enhance the responsivity. To compensate the hydrostatic pressure, a capillary tube is fixed at the end of the hydrophone. Both theoretical and experimental investigations are presented in this paper. The result shows that the proposed design has a high sensitivity of a flat frequency response below 1 kHz.

  10. Investigation on a pressure-gradient fiber laser hydrophone

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    In this paper, a pressure-gradient fiber laser hydrophone is demonstrated. Two brass diaphragms are installed at the end of a metal cylinder as sensing elements. A distributed feedback fiber laser, fixed at the center of the two diaphragms, is elongated or shortened due to the acoustic wave. There are two orifices at the middle of the cylinder. So this structure can work as a pressure-gradient microphone in the acoustic field. Furthermore, the hydrostatic pressure is self-compensated and an ultra-thin dimension is achieved. Theoretical analysis is given based on the electro-acoustic theory. Field trials are carried out to test the performance of the hydrophone. A sensitivity of 100 nm MPa-1 has been achieved. Due to the small dimensions, no directivity is found in the test.

  11. 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

    2014-05-05

    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.

  12. 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.

  13. 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.

  14. 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…

  15. Fiber-integrated tungsten disulfide saturable absorber (mirror) for pulsed fiber lasers

    NASA Astrophysics Data System (ADS)

    Chen, Hao; Li, Irene Ling; Ruan, Shuangchen; Guo, Tuan; Yan, Peiguang

    2016-08-01

    We propose two schemes for achieving tungsten disulfide (WS2)-based saturable absorber (SA) and saturable absorber mirror (SAM). By utilizing the pulsed laser deposition method, we grow the WS2 film on microfiber to form an evanescent field interaction SA device. Incorporating this SA device into a common ring-cavity erbium-doped fiber (EDF) laser, stably passive mode-locking can be achieved with pulse duration of 395 fs and signal-to-noise ratio of 64 dB. We also produce a fiber tip integrated WS2-SAM by utilizing the magnetron sputtering technique (MST). This new type of SAM combines the WS2 layer as SA and gold mirror as high reflective mirror. By employing the WS2-SAM, we construct the linear-cavity EDF lasers, and achieve passive mode-locking operation with pulse duration of ˜1 ns and SNR of ˜61 dB. We further achieve stably passive Q-switching operation with pulse duration of ˜160 ns and pulse energy of 54.4 nJ. These fiber-integrated SAs and SAMs have merits of compactness and reliability, paving the way for the development of new photonic devices such as SAs for pulsed laser technology.

  16. Electron Acceleration Using Hollow Fiber with Table Top Terawatt Laser

    NASA Astrophysics Data System (ADS)

    Mizuta, Yoshio; Kondo, Kiminori; Zhenglin, Chen; Nakabayashi, Takashi; Nakanii, Nobuhiko; Kodama, Ryosuke; Mima, Kunioki; Tanaka, Kazuo

    2008-11-01

    A table top laser system can produce over 10TW laser pulse in present. If we focus these optical pulses to μm size, the focused intensity can be relativistic for electrons. In such a high field, the electron plasma wave (EPW) can be excited. This EPW is attractive for the accelerating field for charged particles. However, the effective interaction length is only a few hundred micro meters. For GeV electron acceleration, this short interaction length should be overcome. A simple hollow fiber is used for obtaining a longer acceleration distance. The spot diameter and the length of focused area should be 10μm and 10mm, respectively. We used the hollow fiber which has 20μm inner diameter and 10mm length. To fill the fiber with enough density atoms with keeping a good vacuum condition, the differential pumping system was used. Presently, we have succeeded in injecting μJ femtosecond pulses into the fine hollow fiber in the atmosphere. In this propagation, a strong self phase modulation occurred to generate a white light. Our plan for coming experiment and possible limiting factors will be discussed.

  17. 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

  18. Fiber photo-catheters for laser treatment of atrial fibrillation

    PubMed Central

    Peshko, Igor; Rubtsov, Vladimir; Vesselov, Leonid; Sigal, Gennady; Laks, Hillel

    2009-01-01

    A fiber photo-catheter has been developed for surgical treatment of atrial fibrillation with laser radiation. Atrial fibrillation (AF) is a heart rhythm abnormality that 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. PMID:19587838

  19. [94 km Brillouin distributed optical fiber sensors based on ultra-long fiber ring laser pumping].

    PubMed

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

    2014-05-01

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

  20. Fiber Bragg grating inscriptions in multimode fiber using 800 nm femtosecond laser

    NASA Astrophysics Data System (ADS)

    Rong, Qiangzhou; Qiao, Xueguang

    2015-09-01

    A short fiber Bragg grating (FBG) was successfully written in a multimode fiber (MMF) tube with core and cladding diameters of 105 μm and 125 μm using 800 nm femtosecond laser. A side-illumination technique was utilized to ensure the grating inscriptions regain over the core of MMF. Both fundamental mode and high-order modes of MMF are coupled at the core-mismatch junction and appear as two well-defined resonances in transmission. Femtosecond laserwritten three FBG-types present good thermostability up to 900 °C.

  1. 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.

  2. Development of Tm:fiber laser-pumped Ho:YLF laser

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    A 2-micron Ho:YLF laser end-pumped by 1.94-micron Tm:fiber laser was developed. A ring resonator oscillator of 3 m length and amplifier system was adopted. The laser was operated at high repetition rates of 200-5000 Hz in room temperature. The amplifier outputs were about 7.4W in CW and more than 6 Win Q-switch operation of repetition rates more than 500 Hz. This laser was developed to be used for coherent wind and CO2 measurements. Then, injection seeding was applied to the ring resonator and single mode laser emission was obtained. The laser was used for Doppler wind lidar measurements and wind profiles were obtained.

  3. Laser Welding of Copper Using Multi Mode Fiber Lasers at Near Infrared Wavelength

    NASA Astrophysics Data System (ADS)

    Liebl, S.; Wiedenmann, R.; Ganser, A.; Schmitz, P.; Zaeh, M. F.

    Due to the increasing electrification of automotive drives and the expansion of decentralized renewable energygeneration, the consumption of copper for the fabrication of electrical components such as electric motors or conducting paths increases. To jointhese components, laser welding is more frequently used since it represents a flexible and fully automatable joining process. Because of the high thermal conductivity, the low absorption coefficient forinfrared wavelength of common laser beam sources and the resulting limited process efficiency, welding of copper alloys represents a major challenge for laser assisted processes. In this paper, experimental investigationsare presented to identify arising process limits during laser welding of pure copper materials with multi-mode fiber lasers at near infrared wavelength depending on the applied laser power and welding velocity. In addition, a potential stabilization of the welding process by shielding gas support was examined. Further investigations were focused on the influence of shielding gas on the molten pool geometry.

  4. Influence of the fiber Bragg gratings with different reflective bandwidths in high power all-fiber laser oscillator

    NASA Astrophysics Data System (ADS)

    Wang, Jianming; Yan, Dapeng; Xiong, Songsong; Huang, Bao; Li, Cheng

    2017-01-01

    The effects of large-mode-area (LMA) fiber Bragg gratings (FBGs) with different reflective bandwidths on bi-directionally pumped ytterbium-doped single-mode all-fiber laser oscillator have been investigated experimentally. The forward laser output power and the backward signal leakage were measured and analyzed. It was found that the laser output power and efficiency depended on the bandwidth of the high-reflection (HR) FBG used in the laser cavity. The broader bandwidth gives higher laser efficiency, especially at high power level.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Solutions of kW Continuous-wave All-fiber Laser

    NASA Astrophysics Data System (ADS)

    Dapeng, Yan; Libo, Li; Xiaoxu, Liu; Dayong, Min

    2011-02-01

    Solutions of kW continuous-wave (CW) all-fiber laser are proposed. In our solutions, master oscillator power amplifier (MOPA) configuration is applied. Output power of master oscillator is 10W, and then is amplified to 70W with 1st pre-amplifier and next scaled up to 400W. Finally, 400W fiber laser is used as a basic power unit, and 1000W all-fiber laser can be achieved by means of beam combining with large core double clad fiber (DCF) combiner. In this solution, fiber laser has good stability and reliability for dispersion coupling of pump source and inhibition of photon darkening effect in the fiber. In addition, this solution assures us realize a 1000W all-fiber laser product easily, and the cost is low.

  10. Experimental verification of fiber-coupling efficiency for satellite-to-ground atmospheric laser downlinks.

    PubMed

    Takenaka, Hideki; Toyoshima, Morio; Takayama, Yoshihisa

    2012-07-02

    Optical communication is a high-capacity method that can handle considerable satellite data. When common-fiber optical devices such as optical fiber amplifiers based on single mode fibers are used in free-space laser communication systems, the laser beam has to be coupled to a single-mode fiber. Under atmospheric turbulence it would be difficult to make the required fiber coupling efficiency in satellite-to-ground laser propagation paths. A fast-steering mirror that can operate at high frequencies under atmospheric turbulence is fabricated, and its tracking performance is verified in real satellite-to-ground laser communication experiments. The measured fiber coupling loss of 10-19 dB in satellite-to-ground laser communication links under atmospheric turbulence shows good agreement with the predicted fiber coupling efficiency of 17 dB.

  11. 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.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

  14. 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.

  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.

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

    NASA Astrophysics Data System (ADS)

    Sudo, Masaaki; Takayanagi, Jun; Ohtake, Hideyuki

    2016-11-01

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

  17. High-power 83 W holmium-doped silica fiber laser operating with high beam quality.

    PubMed

    Jackson, Stuart D; Sabella, Alex; Hemming, Alex; Bennetts, Shayne; Lancaster, David G

    2007-02-01

    A high-power 83 W cladding-pumped Tm3+-Ho3+-doped silica fiber laser is reported. Using bidirectional 793 nm diode pumping, a maximum slope efficiency of 42% was produced after a threshold launched pump power of 12 W was exceeded. The laser operated at wavelengths near 2105 nm with moderate beam quality, i.e., M2 approximately 1.5. Further power scaling of the fiber laser was limited by thermal failure of the fiber ends.

  18. High-power 83 W holmium-doped silica fiber laser operating with high beam quality

    NASA Astrophysics Data System (ADS)

    Jackson, Stuart D.; Sabella, Alex; Hemming, Alex; Bennetts, Shayne; Lancaster, David G.

    2007-02-01

    A high-power 83W cladding-pumped Tm3+-Ho3+-doped silica fiber laser is reported. Using bidirectional 793nm diode pumping, a maximum slope efficiency of 42% was produced after a threshold launched pump power of 12W was exceeded. The laser operated at wavelengths near 2105nm with moderate beam quality, i.e., M2˜1.5. Further power scaling of the fiber laser was limited by thermal failure of the fiber ends.

  19. Spectrally beam combined fiber lasers for high power, efficiency, and brightness

    NASA Astrophysics Data System (ADS)

    Honea, Eric; Afzal, Robert S.; Savage-Leuchs, Matthias; Gitkind, Neil; Humphreys, Richard; Henrie, Jason; Brar, Khush; Jander, Don

    2013-03-01

    Spectral Beam Combining (SBC) of fiber lasers provides a simple, robust architecture for power scaling lasers to high power. With appropriate designs, power scaling beyond the single fiber limit can be achieved while maintaining near diffraction limited beam quality and high efficiency. We present experimental results where we achieved > 3 kW at an M2 = 1.35 and > 39% E-O efficiency by combining 12 individual fiber lasers into a single high brightness beam.

  20. 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

  1. 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.

  2. Long-distance fiber-optic point-sensing systems based on random fiber lasers.

    PubMed

    Wang, Z N; Rao, Y J; Wu, H; Li, P Y; Jiang, Y; Jia, X H; Zhang, W L

    2012-07-30

    We find that the random fiber laser (RFL) without point-reflectors is a temperature-insensitive distributed lasing system for the first time. Inspired by such thermal stability, we propose the novel concept of utilizing the RFL to achieve long-distance fiber-optic remote sensing, in which the RFL offers high-fidelity and long-distance transmission for the sensing signal. Two 100 km fiber Bragg grating (FBG) point-sensing schemes based on RFLs are experimentally demonstrated using the first-order and the second-order random lasing, respectively, to verify the concept. Each sensing scheme can achieve >20 dB optical signal-to-noise ratio (OSNR) over 100 km distance. It is found that the second-order random lasing scheme has much better OSNR than that of the first-order random lasing scheme due to enhanced lasing efficiency, by incorporating a 1455 nm FBG into the lasing cavity.

  3. Remote high temperature sensing with a reflective bandpass long-period fiber grating and a fiber ring laser

    NASA Astrophysics Data System (ADS)

    Hou, Yusong; Zhu, Tao; Shi, Leilei; Zhang, Qiang; Chiang, Kin Sing

    2013-09-01

    We demonstrate a remote high temperature fiber sensing system, where the sensing element is a long-period fiber grating (LPFG) fusion-spliced to a short section of a hollow-core fiber (HCF) and sensor interrogation is achieved with a fiber ring laser. The HCF turns the LPFG from a band-rejection filter into a reflective bandpass filter, while the ring laser selects the reflected wavelength from the LPFG sensor. Our experimental sensor shows a sensitivity of 0.095 nm °C-1 over the temperature range from 150 to 600 °C and the sensing distance is about 1 km.

  4. 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.

  5. Switchable dual-wavelength fiber laser based on semiconductor optical amplifier and polarization-maintaining fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Feng, Suchun; Xu, Ou; Lu, Shaohua; Ren, Wenhua; Jian, Shuisheng

    2008-12-01

    Switchable dual-wavelength with orthogonal polarizations fiber laser based on semiconductor optical amplifier (SOA) and polarization-maintaining fiber Bragg grating (PMFBG) at room temperature is proposed. Owing to the polarization dependent loss of the PMFBG, the laser can be designed to operate in stable dual-wavelength or wavelength-switching modes with a wavelength spacing of 0.336 nm at room temperature by adjusting the polarization controller (PC). The amplitude variation in nearly half an hour is less than 0.1 dB for both wavelengths, which is more stable than that of erbium doped fiber (EDF)-based laser with similar configuration.

  6. 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.

  7. Efficient femtosecond pulse generation in an all-normal-dispersion Yb:fiber ring laser at 605 MHz repetition rate.

    PubMed

    Yang, Hongyu; Wang, Aimin; Zhang, Zhigang

    2012-03-01

    We report a 1030 nm-wavelength Yb:fiber laser that produces the shortest/direct output pulse duration (502 fs) among all-normal-dispersion fiber lasers at the highest repetition rate (605 MHz) among the passively fundamentally mode-locked fiber lasers. The laser also exhibits an optical efficiency of 70% at CW and 65% at mode-locking modes.

  8. Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

    PubMed

    Dawson, Jay W; Messerly, Michael J; Beach, Raymond J; Shverdin, Miroslav Y; Stappaerts, Eddy A; Sridharan, Arun K; Pax, Paul H; Heebner, John E; Siders, Craig W; Barty, C P J

    2008-08-18

    We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier. This power limit is determined by thermal and non-linear limits that combine to prevent further power scaling, irrespective of increases in mode size. However, limits to the scaling of the MFD may restrict fiber lasers to lower output powers.

  9. 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.

  10. Adaptive ultrasonic sensor using a fiber ring laser with tandem fiber Bragg gratings.

    PubMed

    Liu, Tongqing; Hu, Lingling; Han, Ming

    2014-08-01

    We propose and demonstrate an intensity-demodulated fiber-optic ultrasonic sensor system that can be self-adaptive to large quasi-static background strain perturbations. The sensor system is based on a fiber ring laser (FRL) whose laser cavity includes a pair of fiber Bragg gratings (FBGs). Self-adaptive ultrasonic detection is achieved by a tandem design where the two FBGs are engineered to have differential spectral responses to ultrasonic waves and are installed side-by-side at the same location on a structure. As a result, ultrasonic waves lead to relative spectral shifts of the FBGs and modulations to the cold-cavity loss of the FRL. Ultrasonic waves can then be detected directly from the laser intensity variations in response to the cold-cavity loss modulation. The sensor system is insensitive to quasi-static background strains because they lead to identical responses of the tandem FBGs. Based on the principle, a FRL sensor system was demonstrated and tested for adaptive ultrasonic detection when large static strains as well as dynamic sinusoidal vibrations were applied to the sensor.

  11. 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.

  12. 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.

  13. High power ytterbium-doped fiber lasers — fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Zervas, Michalis N.

    2014-03-01

    In this paper, we summarize the fundamental properties and review the latest developments in high power ytterbium-doped fiber (YDF) lasers. The review is focused primarily on the main fiber laser configurations and the related cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancements observed in high power fiber lasers. The review also includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, modal instabilities and photodarkening. The paper summarizes the power evolution in continuous-wave (CW) and pulsed YDF lasers and their impact on material processing and other industrial applications.

  14. 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.

  15. High-efficiency generation in a short random fiber laser

    NASA Astrophysics Data System (ADS)

    Vatnik, I. D.; Churkin, D. V.; Podivilov, E. V.; Babin, S. A.

    2014-07-01

    We demonstrate a high-efficiency random lasing in a 850 m span of a phosphosilicate fiber. Random distributed feedback owing to the Rayleigh backscattering in the fiber enables narrowband generation with output power of up to 7.3 W at the Stokes wavelength λS = 1308 nm from 11 W of the pump power at λP = 1115 nm. The laser demonstrates unique generation efficiency. Near the generation threshold, more than 2 W of output power is generated from only 0.5 W of pump power excess over the generation threshold. At high pump power, the quantum conversion efficiency defined as a ratio of generated and pump photons at the laser output exceeds 100%. It is explained by the fact that every pump photon is converted into the Stokes photon far from the output fiber end, while the Stokes photons have lower attenuation than the pump photons.

  16. 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.

  17. Modeling synchronization in networks of delay-coupled fiber ring lasers.

    PubMed

    Lindley, Brandon S; Schwartz, Ira B

    2011-11-21

    We study the onset of synchronization in a network of N delay-coupled stochastic fiber ring lasers with respect to various parameters when the coupling power is weak. In particular, for groups of three or more ring lasers mutually coupled to a central hub laser, we demonstrate a robust tendency toward out-of-phase (achronal) synchronization between the N-1 outer lasers and the single inner laser. In contrast to the achronal synchronization, we find the outer lasers synchronize with zero-lag (isochronal) with respect to each other, thus forming a set of N-1 coherent fiber lasers.

  18. 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.

  19. High-power continuous-wave cladding-pumped Raman fiber laser.

    PubMed

    Codemard, C A; Dupriez, P; Jeong, Y; Sahu, J K; Ibsen, M; Nilsson, J

    2006-08-01

    We demonstrate a high-power single-mode cladding-pumped Raman fiber laser. The Raman fiber laser consists of a 1.2 km long germanium-doped double-clad fiber in a linear cavity, which is spliced to a single-mode fiber. The laser is end pumped by a multimode erbium-ytterbium-doped fiber, which is coupled to the inner cladding of the Raman fiber. The embedded core was designed to be single mode at the Raman Stokes wavelength, and up to 10 W of power was obtained at 1660 nm from the single-mode fiber end. The laser has a slope efficiency of 67% and a threshold of 6.5 W.

  20. Pulsed operation of Tm-doped fiber lasers using piezoelectric-driven microbend applied to elliptical coating fibers

    NASA Astrophysics Data System (ADS)

    Sakata, H.; Kimpara, K.; Komori, K.; Tomiki, M.

    2014-05-01

    We report Q-switched pulse generation in Tm-doped fiber lasers by introducing piezoelectric-driven microbend into an elliptical coating fiber in a fiber ring resonator. Compared with the untreated circular fiber having a diameter of 240 μm, the elliptical coating fiber was flattened to have a major axis diameter of about 300 μm. We employed a pair of comblike plates attached on the piezoelectric actuators in order to bend the fiber from both sides. The output pulse power is improved by optimizing the tooth-width and spatial period of the comb-like plates, so that the elliptical coating fiber is easily bent and the propagation mode is efficiently coupled to radiation modes around λ = 1.9 μm. The Tm-doped fiber is pumped by a laser diode emitting at 1.63 μm and the pump light is introduced to the fiber ring resonator via the wavelength division multiplexing coupler. The emission spectra showed that the center oscillation wavelength was typically 1.92 μm. When the pump power was increased to 156 mW, the output pulse showed a peak power of 42.5 W with a pulse width of 1.06 μs. We expect that the in-fiber Q-switching technique will provide simple laser systems for environmental sensing and medical applications.

  1. Yb³⁺-doped large core silica fiber for fiber laser prepared by glass phase-separation technology.

    PubMed

    Chu, Yingbo; Ma, Yunxiu; Yang, Yu; Liao, Lei; Wang, Yibo; Hu, Xiongwei; Peng, Jinggang; Li, Haiqing; Dai, Nengli; Li, Jinyan; Yang, Luyun

    2016-03-15

    We report on the preparation and optical characteristics of an Yb(3+)-doped large core silica fiber with the active core prepared from nanoporous silica rod by the glass phase-separation technology. The measurements show that the fiber has an Yb(3+) concentration of 9811 ppm by weight, a low background attenuation of 0.02 dB/m, and absorption from Yb(3+) about 5.5 dB/m at 976 nm. The laser performance presents a high slope efficiency of 72.8% for laser emission at 1071 nm and a low laser threshold of 3 W within only 2.3 m fiber length. It is suggested that the glass phase-separation technology shows great potential for realizing active fibers with larger core and complex fiber designs.

  2. CO2 Laser Cutting of Glass Fiber Reinforce Polymer Composite

    NASA Astrophysics Data System (ADS)

    Fatimah, S.; Ishak, M.; Aqida, S. N.

    2012-09-01

    The lamination, matrix properties, fiber orientation, and relative volume fraction of matrix of polymer structure make this polymer hard to process. The cutting of polymer composite using CO2 laser could involve in producing penetration energy in the process. Identification of the dominant factors that significantly affect the cut quality is important. The objective of this experiment is to evaluate the CO2 spot size of beam cutting for Glass Fiber Reinforce Polymer Composite (GFRP). The focal length selected 9.5mm which gave smallest focus spot size according to the cutting requirements. The effect of the focal length on the cut quality was investigated by monitoring the surface profile and focus spot size. The beam parameter has great effect on both the focused spot size and surface quality.

  3. Fiber optic coherent laser radar 3D vision system

    SciTech Connect

    Clark, R.B.; Gallman, P.G.; Slotwinski, A.R.; Wagner, K.; Weaver, S.; Xu, Jieping

    1996-12-31

    This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution.

  4. Tissue effects of Nd:YAG, KTP, and FiberTomeTM lasers with varying fiber tips and power settings

    NASA Astrophysics Data System (ADS)

    Vari, Sandor G.; Snyder, Wendy J.; Pergadia, Vani R.; Fishbein, Michael C.; Weiss, Andrew B.; Duffy, J. T.; Thomas, Reem; Shi, Wei-Qiang; Fry, Stephen M.; Grundfest, Warren S.

    1994-02-01

    This study compared the laser tissue effect of the Dornier FiberTomeTM system, the conventional Nd:YAG and the KTP laser on the stomach and liver. The cutting capabilities, thermal effects of the laser systems, as well as their dependence on power output and tissue type, were evaluated. A motorized fiber holder to maintain constant conditions (cutting speed fiber angle, and pressure) was developed. The results show that the cutting depth and cutting width are inversely proportional to the output level. The thermal damage remained constant as the output increased. Use of the FiberTomeTM system appears to be more advantageous than the conventional Nd:YAG laser in pigmented tissues, in the range of the parameters tested.

  5. 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.

  6. Highly scalable, resonantly cladding-pumped, Er-doped fiber laser with record efficiency.

    PubMed

    Dubinskii, M; Zhang, J; Ter-Mikirtychev, V

    2009-05-15

    We report the performance of a resonantly cladding-pumped, Yb-free, Er-doped fiber laser. We believe this is the first reported resonantly cladding-pumped fiber-Bragg-grating-based, Er-doped, large-mode-area (LMA) fiber laser. The laser, pumped by fiber-coupled InGaAsP/InP laser diode modules at 1,532.5 nm, delivers approximately 48 W of cw output at 1,590 nm. It is believed to be the highest power ever reported from a Yb-free Er-doped LMA fiber. This fully integrated laser also has the optical-to-optical efficiency of approximately 57%, to the best of our knowledge, the highest efficiency reported for cladding-pumped unidirectionally emitting Er-doped laser.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  8. Triple-wavelength erbium fiber ring laser based on compound-ring scheme.

    PubMed

    Yeh, Chien Hung; Shih, Fu Yuan; Chen, Chang Tai; Chi, Sien

    2007-12-24

    .A triple-wavelength erbium-doped compound ring fiber laser using the fiber-based triple-ring filter (TRF) is proposed and experimentally investigated. Using the fiber-based TRF laser scheme, the proposed laser can lase three wavelengths simultaneously. The fiber laser retrieve the optical side-mode suppression ratios (SMSRs) of 40.2, 40.4 and 41.6 dB and the output powers of -9, -8.8 and -7.6 dBm at the wavelengths 1555.89, 1556.77 and 1557.66 nm, respectively. The mode spacing of the triple-wavelength fiber laser is nearly 0.9 nm. Moreover, the output power stability of the ring laser has also been measured and analyzed.

  9. Design of high-bandwidth one- and two-dimensional photonic bandgap dielectric structures at grazing incidence of light.

    PubMed

    Fekete, J; Várallyay, Z; Szipocs, R

    2008-10-10

    We propose one-dimensional photonic bandgap (PB) dielectric structures to be used at grazing incidence in order to obtain an extended bandgap exhibiting considerably reduced reflection loss and dispersion compared to similar structures used at a normal incidence of light. The well-known quarter-wave condition is applied for the design in this specific case, resulting in resonance-free reflection bands without drops in reflection versus wavelength function and a monotonous variation of the group delay dispersion versus wavelength function, which are important issues in femtosecond pulse laser applications. Based on these results we extend our studies to two-dimensional PB structures and provide guidelines to the design of leaking mode-free hollow-core Bragg PB fibers providing anomalous dispersion over most of the bandgap.

  10. 2013 R&D 100 Award: New tech could mean more power for fiber lasers

    ScienceCinema

    Dawson, Jay

    2016-07-12

    An LLNL team of six physicists has developed a new technology that is a stepping stone to enable some of the limitations on high-power fiber lasers to be overcome. Their technology, dubbed "Efficient Mode-Converters for High-Power Fiber Amplifiers," allows the power of fiber lasers to be increased while maintaining high beam quality. Currently, fiber lasers are used in machining, on factory floors and in a number of defense applications and can produce tens of kilowatts of power.The conventional fiber laser design features a circular core and has fundamental limitations that make it impractical to allow higher laser power unless the core area is increased. LLNL researchers have pioneered a design to increase the laser's core area along the axis of the ribbon fiber. Their design makes it difficult to use a conventional laser beam, so the LLNL team converted the beam into a profile that propagates into the ribbon fiber and is converted back once it is amplified. The use of this LLNL technology will permit the construction of higher power lasers for lower costs and increase the power of fiber lasers from tens of kilowatts of power to about 100 kilowatts and potentially even higher.

  11. 2013 R&D 100 Award: New tech could mean more power for fiber lasers

    SciTech Connect

    Dawson, Jay

    2014-04-03

    An LLNL team of six physicists has developed a new technology that is a stepping stone to enable some of the limitations on high-power fiber lasers to be overcome. Their technology, dubbed "Efficient Mode-Converters for High-Power Fiber Amplifiers," allows the power of fiber lasers to be increased while maintaining high beam quality. Currently, fiber lasers are used in machining, on factory floors and in a number of defense applications and can produce tens of kilowatts of power.The conventional fiber laser design features a circular core and has fundamental limitations that make it impractical to allow higher laser power unless the core area is increased. LLNL researchers have pioneered a design to increase the laser's core area along the axis of the ribbon fiber. Their design makes it difficult to use a conventional laser beam, so the LLNL team converted the beam into a profile that propagates into the ribbon fiber and is converted back once it is amplified. The use of this LLNL technology will permit the construction of higher power lasers for lower costs and increase the power of fiber lasers from tens of kilowatts of power to about 100 kilowatts and potentially even higher.

  12. All-fiber dual wavelength passive Q-switched fiber laser using a dispersion-decreasing taper fiber in a nonlinear loop mirror.

    PubMed

    Ahmad, Harith; Dernaika, Mohamad; Harun, Sulaiman Wadi

    2014-09-22

    This paper describes a proposal and successful demonstration of a dual wavelength all-fiber passively Q-switched erbium-doped fiber ring laser. The Q-switch operation was realized by using a nonlinear loop mirror that incorporated an unbalanced dispersion-decreasing taper fiber to act as a saturable absorber without additional elements. This setup enabled a fiber ring laser to achieve a performance of 48.7 kHz repetition rate with pulse duration of around 3.2 μs and approximate pulse energy of 20 nJ.

  13. 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.

  14. Laser ultrasound technology for fault detection on carbon fiber composites

    NASA Astrophysics Data System (ADS)

    Seyrkammer, Robert; Reitinger, Bernhard; Grün, Hubert; Sekelja, Jakov; Burgholzer, Peter

    2014-05-01

    The marching in of carbon fiber reinforced polymers (CFRPs) to mass production in the aeronautic and automotive industry requires reliable quality assurance methods. Laser ultrasound (LUS) is a promising nondestructive testing technique for sample inspection. The benefits compared to conventional ultrasound (US) testing are couplant free measurements and an easy access to complex shapes due to remote optical excitation and detection. Here the potential of LUS is present on composite test panels with relevant testing scenarios for industry. The results are evaluated in comparison to conventional ultrasound used in the aeronautic industry.

  15. Possible power source found for fiber optic lasers

    SciTech Connect

    Krupa, Tyler J.

    2000-05-01

    Scientists at the US Department of Energy's Sandia National Laboratory are researching ways to use a new semiconductor alloy, indium gallium arsenide nitride (InGaAsN), as as photovoltaic power source for lasers in fiber optics and space communication satellites. The efficiency of electricity-generating solar cells utilizing InGaAsN is predicted to be 40%-nearly twice the efficiency rate of a standard silicon solar cell. The use of InGaAsN in solar cells is a potential power source for satellites and other space systems. (AIP) (c)

  16. Ultrafast laser inscribed fiber Bragg gratings for sensing applications

    NASA Astrophysics Data System (ADS)

    Mihailov, Stephen J.

    2016-05-01

    Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on femtosecond infrared laser-material processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This tutorial paper will present a review of some of the more recent developments.

  17. Holograms for laser diode: Single mode optical fiber coupling

    NASA Technical Reports Server (NTRS)

    Fuhr, P. L.

    1982-01-01

    The low coupling efficiency of semiconductor laser emissions into a single mode optical fibers place a severe restriction on their use. Associated with these conventional optical coupling techniques are stringent alignment sensitivities. Using holographic elements, the coupling efficiency may be increased and the alignment sensitivity greatly reduced. Both conventional and computer methods used in the generation of the holographic couplers are described and diagrammed. The reconstruction geometries used are shown to be somewhat restrictive but substantially less rigid than their conventional optical counterparts. Single and double hologram techniques are examined concerning their respective ease of fabrication and relative merits.

  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. Fiber laser pumped burst-mode operated picosecond mid-infrared laser

    NASA Astrophysics Data System (ADS)

    Wei, Kai-Hua; Jiang, Pei-Pei; Wu, Bo; Chen, Tao; Shen, Yong-Hang

    2015-02-01

    We demonstrate a compact periodically poled MgO-doped lithium niobate (MgO:PPLN)-based optical parametric oscillator (OPO) quasi-synchronously pumped by a fiber laser system with burst-mode operation. The pump source is a peak-power-selectable pulse-multiplied picosecond Yb fiber laser. The chirped pulses from a figure of eight-cavity mode-locked fiber laser seed are narrowed to a duration of less than 50 ps using an FBG reflector and a circulator. The narrowed pulses are directed to pass through a pulse multiplier and to form pulse bunches, each of which is composed of 13 sub-pulses. The obtained pulse bunches are amplified by two-stage fiber pre-amplifiers: one-stage is core-pumped and the other is cladding-pumped. A fiberized acousto-optic modulator is inserted to control the pulse repetition rate (PRR) of the pulse bunches before they are power-amplified in the final amplifier stage with a large mode area (LMA) PM Yb-doped fiber. The maximum average powers from the final amplifier are 85 W, 60 W, and 45 W, respectively, corresponding to the PRR of 2.72 MHz, 1.36 MHz, and 0.68 MHz. The amplified pulses are directed to pump an MgO:PPLN-based optical parametric oscillator (OPO). A maximum peak power at 3.45 μm is obtained approximately to be 8.4 kW. Detailed performance characteristics are presented. Project supported by the National Natural Science Foundation of China (Grant No. 61078015) and the National Basic Research Program of China (Grant No. 2011CB311803).

  20. Micro-hole drilling and cutting using femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Micro-hole drilling and cutting in ambient air are presented by using a femtosecond fiber laser. At first, the micro-hole drilling was investigated in both transparent (glasses) and nontransparent (metals and tissues) materials. The shape and morphology of the holes were characterized and evaluated with optical and scanning electron microscopy. Debris-free micro-holes with good roundness and no thermal damage were demonstrated with the aspect ratio of 8∶1. Micro-hole drilling in hard and soft tissues with no crack or collateral thermal damage is also demonstrated. Then, trench micromachining and cutting were studied for different materials and the effect of the laser parameters on the trench properties was investigated. Straight and clean trench edges were obtained with no thermal damage.

  1. Fiber-optic laser Doppler turbine tip clearance probe.

    PubMed

    Büttner, Lars; Pfister, Thorsten; Czarske, Jürgen

    2006-05-01

    A laser Doppler based method for in situ single blade tip clearance measurements of turbomachines with high precision is presented for what we believe is the first time. The sensor is based on two superposed fanlike interference fringe systems generated by two laser wavelengths from a fiber-coupled, passive, and therefore compact measurement head employing diffractive optics. Tip clearance measurements at a transonic centrifugal compressor performed during operation at 50,000 rpm (833 Hz, 586 m/s tip speed) are reported. At these speeds the measured uncertainty of the tip position was less than 20 microm, a factor of 2 more accurate than that of capacitive probes. The sensor offers great potential for in situ and online high-precision tip clearance measurements of metallic and nonmetallic turbine blades.

  2. Characterization of the Los Alamos IPG YLR-6000 fiber laser using multiple optical paths and laser focusing optics

    SciTech Connect

    Milewski, John O; Bernal, John E

    2009-01-01

    Fiber laser technology has been identified as the replacement power source for the existing Los Alamos TA-55 production laser welding system. An IPG YLR-6000 fiber laser was purchased, installed at SM-66 R3, and accepted in February 2008. No characterization of the laser and no welding was performed in the Feb 2008 to May 2009 interval. T. Lienert and J. Bernal (Ref. 1, July 2009) determined the existing 200 mm Rofin collimator and focus heads used with the Rofin diode pumped lasers were inadequate for use with the IPG laser due to clipping of the IPG laser beam. Further efforts in testing of the IPG laser with Optoskand fiber delivery optics and a Rofin 120 mm collimator proved problematic due to optical fiber damage. As a result, IPG design optical fibers were purchased as replacements for subsequent testing. Within the same interval, an IPG fiber-to-fiber (F2F) connector, custom built for LANL, (J. Milewski, S. Gravener, Ref.2) was demonstrated and accepted at IPG Oxford, MA in August 2009. An IPG service person was contracted to come to LANL to assist in the installation, training, troubleshooting and characterization of the multiple beam paths and help perform laser head optics characterization. The statement of work is provided below: In summary the laser system, optical fibers, F2F connector, Precitec head, and a modified Rofin type (w/120mm Optoskand collimator) IWindowIBoot system focus head (Figure 1) were shown to perform well at powers up to 6 kW CW. Power measurements, laser spot size measurements, and other characterization data and lessons learned are contained within this report. In addition, a number of issues were identified that will require future resolution.

  3. High-power gain-switched Tm(3+)-doped fiber laser.

    PubMed

    Tang, Yulong; Xu, Lin; Yang, Yi; Xu, Jianqiu

    2010-10-25

    Gain-switched by a 1.914-µm Tm:YLF crystal laser, a two-stage Tm(3+) fiber laser has been achieved 100-W level ~2-µm pulsed laser output with a slope efficiency of ~52%. With the 6-m length of Tm fiber, the laser wavelength was centered at 2020 nm with a bandwidth of ~25 nm. Based on an acousto-optic switch, the pulse repetition rate can be modulated from 500 Hz to 50 kHz, and the laser pulse width can be tuned between 75 ns and ~1 µs. The maximum pulse energy was over 10 mJ, and the maximum pulse peak power was 138 kW. By using the fiber-coiling-induced mode-filtering effect, laser beam quality of M2 = 1.01 was obtained. Further scaling the pulse energy and average power from such kind of gain-switched fiber lasers was also discussed.

  4. Fabrication and sensing characteristics of helical long-period fiber gratings written in the rotated fiber by CO2 laser

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Liu, Yunqi; Song, Hongliang; Wang, Tingyun

    2015-09-01

    A helical long-period grating (HLPG) was fabricated by twisting a conventional single-mode fiber when CO2 laser beam was sweeping along the fiber axis. A grating with a contrast of 20 dB can be written in the fiber with a length of 1 cm. The spectral and sensing characteristics were investigated experimentally. The maximum sensitivity to surrounding refractive index and temperature measurement was measured to be 995 nm/RIU and 53 pm/°C, respectively.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  6. Ablation of selected conducting layers by fiber laser

    NASA Astrophysics Data System (ADS)

    Pawlak, Ryszard; Tomczyk, Mariusz; Walczak, Maria

    2014-08-01

    Laser Direct Writing (LDW) are used in the manufacture of electronic circuits, pads, and paths in sub millimeter scale. They can also be used in the sensors systems. Ablative laser writing in a thin functional layer of material deposited on the dielectric substrate is one of the LDW methods. Nowadays functional conductive layers are composed from graphene paint or nanosilver paint, indium tin oxide (ITO), AgHTTM and layers containing carbon nanotubes. Creating conducting structures in transparent layers (ITO, AgHT and carbon nanotubes layers) may have special importance e.g. for flexi electronics. The paper presents research on the fabrication of systems of paths and appropriate pattern systems of paths and selected electronic circuits in AgHTTM and ITO layers deposited on glass and polymer substrates. An influence of parameters of ablative fiber laser treatment in nanosecond regime as well as an influence of scanning mode of laser beam on the pattern fidelity and on electrical parameters of a generated circuit was investigated.

  7. Studies on output characteristics of stable dual-wavelength ytterbium-doped photonic crystal fiber laser

    NASA Astrophysics Data System (ADS)

    Tian, Hongchun; Zhang, Sa; Hou, Zhiyun; Xia, Changming; Zhou, Guiyao; Zhang, Wei; Liu, Jiantao; Wu, Jiale; Fu, Jian

    2016-06-01

    A stable dual-wavelength ytterbium-doped photonic crystal fiber laser pumped by a 976 nm laser diode has been demonstrated at room temperature. Single-wavelength, dual-wavelength laser oscillations are observed when the fiber laser operates under different pump power by using different length of fibers. Stable dual-wavelength radiation around 1045 nm and 1075 nm has been generated simultaneously at a high pump power directly from an ytterbium-doped fiber laser without using any spectral control mechanism. A small core ytterbium-doped PCF fabricated by the powder sinter direction drawn rod technology is used as gain medium. The pump power and fiber length which can affect the output characteristics of dual-wavelength fiber laser are analyzed in the experiment. Experiments confirm that higher pump power and longer fiber length favors 1075 nm output; lower pump power and shorter fiber length favors 1045 nm output. Those results have a good reference in multi-wavelength fiber laser.

  8. 63W output tandem-pumped thulium-doped silica fiber laser at 1980 nm

    NASA Astrophysics Data System (ADS)

    Xing, Ying-bin; Bu, Fan; Wang, Yi-bo; Li, Hai-qing; Peng, Jing-gang; Yang, Lv-yun; Dai, Neng-li; Li, Jin-yan

    2016-11-01

    We have demonstrated a high power and high efficiency thulium-doped silica fiber laser using a cascade tandem pumping method. A 1915nm Tm-doped fiber laser was used as a pump source for another Tm-doped fiber laser with the output power of 63W at 1980nm, corresponding to the slope efficiency of 80%, which is the highest power to our best knowledge. And the 3dB bandwidth was 0.24nm. The 1915nm Tm-doped fiber laser was pumped by 793nm diode laser and the slope efficiency was 51%. The preform of double cladding Tm-doped fiber for the tandem pumped fiber laser was manufactured by MCVD with using the vapor-solution hybrid doping method. The fiber has a 25μm diameter, 0.098 NA(numerical aperture) core and 400μm diameter, 0.46 NA inner cladding. In the tandem pumped fiber laser, the resonant cavity consist of a high reflection FBG at 1980nm, flat fiber end and the homemade Tm-doped silica fiber. The optimal active fiber length was presented and it is found that when the length of homemade Tm-doped silica fiber was 7m, the efficiency was the highest. The influence of Tm concentration and ratio of Tm ion and Al ion on the efficiency was also explored. And it is found that the thulium-doped silica fiber with lower Tm concentration and higher Tm:Al ratio had lower optical efficiency. Meanwhile, the optimal fiber length became shorter.

  9. Laser diode fiber optic apparatus for acupuncture treatment by the Oriental method

    NASA Astrophysics Data System (ADS)

    Pham, Van Hoi; Phung, Huu A.; Bui, Huy; Hoang, Cao D.; Vu, Duc T.; Tran, Minh T.; Nguyen, Minh H.

    1998-08-01

    The laser acupuncture equipment using laser diodes of 850, 1300 nm and optical fibers as light needles is presented. The double-frequency modulation of laser beam gives the high efficiency treatment of the low-power laser therapy by the oriental acupuncture method. The laser spot from optical fiber of 50 microns is suitable for the irradiation into special points on body or auricular by the acupuncture treatment schema. The laser intensity in pulse regime of 5 - 40 W/cm2 and irradiation time of 5 - 15 minutes are optimum for treatment of neurosis symptoms and pain-relieving.

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

    PubMed

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

    2015-11-01

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

  11. Laser Communications and Fiber Optics Lab Manual. High-Technology Training Module.

    ERIC Educational Resources Information Center

    Biddick, Robert

    This laboratory training manual on laser communications and fiber optics may be used in a general technology-communications course for ninth graders. Upon completion of this exercise, students achieve the following goals: match concepts with laser communication system parts; explain advantages of fiber optic cable over conventional copper wire;…

  12. QUANTITATIVE DETECTION OF ENVIRONMENTALLY IMPORTANT DYES USING DIODE LASER/FIBER-OPTIC RAMAN

    EPA Science Inventory

    A compact diode laser/fiber-optic Raman spectrometer is used for quantitative detection of environmentally important dyes. This system is based on diode laser excitation at 782 mm, fiber optic probe technology, an imaging spectrometer, and state-of-the-art scientific CCD camera. ...

  13. Photodegradation and photocuring in the operation of a blue upconversion fiber laser

    SciTech Connect

    Qin Guanshi; Huang Shenghong; Feng Yan; Shirakawa, A.; Musha, M.; Ueda, Ken-ichi

    2005-06-15

    Photodegradation and photocuring effects were investigated in the operation of a Tm{sup 3+}-doped blue upconversion fiber laser. Our experimental results indicate that a competition between photodegradation and photocuring greatly affects the maximum output power of a blue upconversion fiber laser.

  14. Damage of silica-based optical fibers in laser supported detonation

    NASA Astrophysics Data System (ADS)

    Efremov, V. P.; Fortov, V. E.; Frolov, A. A.

    2015-11-01

    The study of detonation-like mode of laser induced damage propagation is presented. This mode is new investigation object of laser destruction of silica-based optical fibers. The fiber destruction images were obtained in evolution and in static (on saved samples).

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

    PubMed Central

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

    2016-01-01

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

  16. Numerical simulation of Nd-fluoride and tellurite solar-pumped fiber lasers

    NASA Astrophysics Data System (ADS)

    Suzuki, Takenobu; Nasu, Hiroyuki; Mizuno, Shintaro; Ito, Hiroshi; Hasegawa, Kazuo; Ohishi, Yasutake

    2012-02-01

    Numerical simulation of Nd-doped fluoride and tellurite fiber lasers pumped directly by sunlight have been performed. Calculations have been done for double clad fibers to achieve both efficient coupling sunlight with a fiber and spatial power condensation. The pumping source was assumed to be initially AM1.5 sunlight and was focused onto a fiber end. The both ends of the fiber were assumed to be transparent for at the pump wavelength and highly reflective at laser wavelength. It was assumed that the launched sunlight propagate in one longitudinal direction in the inner but the laser light propagate in both longitudinal directions in the core. Propagation equations were solved under boundary conditions determined by the reflectivity of the fiber ends by a boundary value problem solver in MATLAB. The calculated sunlight concentration ratio at lasing threshold was about 300 suns for solar pumped fiber lasers with optimized structure. This sunlight concentration can be achieved by conventional optics such as lenses and ellipsoidal mirrors. The slope efficiency was about 0.78 % for a fluoride fiber and 1.32 % for a tellurite fiber. These efficiencies are can be improved by farther optimization of fiber parameters and pumping scheme. Solar pumped fiber lasers will be able to provide alternative means to utilize solar power.

  17. Optical fiber sensing and communication systems using fiber and microchip laser sources

    NASA Astrophysics Data System (ADS)

    Chen, Junewen; Chien, Pie-Yau; Lin, Jun-Ting

    2004-05-01

    Fiber optic strain sensor systems using fiber Bragg grating have been developed in our Section with time demultiplexing phase stabilized feed back Fabry-Perot tunable filter and signal processing technologies. The system can resolve < 1 μ strain, with measuring range of 4000 μ strain; and can monitor 20 points simultaneously. It has been used in real time long term hazard investigation and warning system on the bridges and traffic high-pass ways. The data from these smart fiber optic distributed stress and strain sensing systems had constantly been observed with satisfactory results. Our fiber optic communication system is a bi-directional audio-video and data signal transmission system. The source laser diodes are TE cooled with temperature control circuits. The system is dual audio bi-directional transmission and receiving channel with bandwidth 4.8 KHz. Video one direction transmission and receiving, meets NTSC specification with bandwidth 6 MHz. Dual data signals bi-directional transmission adn receiving channel, meets RS-232C specification and the Buad rate are 9.6 Kbps. The sstems are carefully designed and fabricated to meet the environmental wide temperature range conditions as well as high vibration and shock mobile transportation.

  18. Femtosecond laser bone ablation with a high repetition rate fiber laser source.

    PubMed

    Mortensen, Luke J; Alt, Clemens; Turcotte, Raphaël; Masek, Marissa; Liu, Tzu-Ming; Côté, Daniel C; Xu, Chris; Intini, Giuseppe; Lin, Charles P

    2015-01-01

    Femtosecond laser pulses can be used to perform very precise cutting of material, including biological samples from subcellular organelles to large areas of bone, through plasma-mediated ablation. The use of a kilohertz regenerative amplifier is usually needed to obtain the pulse energy required for ablation. This work investigates a 5 megahertz compact fiber laser for near-video rate imaging and ablation in bone. After optimization of ablation efficiency and reduction in autofluorescence, the system is demonstrated for the in vivo study of bone regeneration. Image-guided creation of a bone defect and longitudinal evaluation of cellular injury response in the defect provides insight into the bone regeneration process.

  19. New method of writing long-period fiber gratings using high-frequency CO2 laser

    NASA Astrophysics Data System (ADS)

    Guo, Gao-Ran; Song, Ying; Zhang, Wen-Tao; Jiang, Yue; Li, Fang

    2016-11-01

    In the paper, the Long period fiber gratings (LPFG) were fabricated in a single-mode fiber using a high frequency CO2 laser system with the point-to-point technique. The experimental setup consists of a CO2 laser controlling system, a focusing system located at a motorized linear stage, a fiber alignment stage, and an optical spectrum analyzer to monitor the transmission spectrum of the LPFG. The period of the LPFG is precisely inscribed by periodically turning on/off the laser shutter while the motorized linear stage is driven to move at a constant speed. The efficiency of fiber writing process is improved.

  20. ArF excimer laser microprocessing of polymer optical fibers for photonic sensor applications

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    A study of polymer optical fiber microstructuring by use of deep ultraviolet excimer laser radiation at 193 nm wavelength is performed. The ablation characteristics of the fiber cladding and core materials are analyzed comparatively. The laser irradiation effects are dynamically studied by on-line monitoring of the laser ablation induced waveguiding losses, the latter being correlated with the spatial structuring parameters. The fiber surface is modified to incorporate cavities, which are subsequently employed as sensitive material receptors for the development of customized photonic sensors. The sensing capability of the microstructured plastic optical fibers is demonstrated by ammonia and humidity detection.