Showing papers on "Fiber laser published in 2009"
TL;DR: In this paper, the use of atomic layer graphene as saturable absorber in a mode-locked fiber laser for the generation of ultrashort soliton pulses (756 fs) at the telecommunication band is demonstrated.
Abstract: The optical conductance of monolayer graphene is defined solely by the fine structure constant, α = (where e is the electron charge, is Dirac's constant and c is the speed of light). The absorbance has been predicted to be independent of frequency. In principle, the interband optical absorption in zero-gap graphene could be saturated readily under strong excitation due to Pauli blocking. Here, use of atomic layer graphene as saturable absorber in a mode-locked fiber laser for the generation of ultrashort soliton pulses (756 fs) at the telecommunication band is demonstrated. The modulation depth can be tuned in a wide range from 66.5% to 6.2% by varying the graphene thickness. These results suggest that ultrathin graphene films are potentially useful as optical elements in fiber lasers. Graphene as a laser mode locker can have many merits such as lower saturation intensity, ultrafast recovery time, tunable modulation depth, and wideband tunability.
2,217 citations
Posted Content•
TL;DR: In this paper, the authors demonstrate the use of atomic layer graphene as saturable absorber in a mode-locked fiber laser for the generation of ultrashort soliton pulses (756 fs) at the telecommunication band.
Abstract: The optical conductance of monolayer graphene is defined solely by the fine structure constant. The absorbance has been predicted to be independent of frequency. In principle, the interband optical absorption in zero-gap graphene could be saturated readily under strong excitation due to Pauli blocking. Here, we demonstrate the use of atomic layer graphene as saturable absorber in a mode-locked fiber laser for the generation of ultrashort soliton pulses (756 fs) at the telecommunication band. The modulation depth can be tuned in a wide range from 66.5% to 6.2% by varying the thickness of graphene. Our results suggest that ultrathin graphene films are potentially useful as optical elements in fiber lasers. Graphene as a laser mode locker can have many merits such as lower saturation intensity, ultrafast recovery time, tunable modulation depth and wideband tuneability.
2,039 citations
TL;DR: Results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking and stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser.
Abstract: We report on large energy pulse generation in an erbium-doped fiber laser passively mode-locked with atomic layer graphene. Stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser. Our results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking.
491 citations
TL;DR: In this article, a graphene-polymer nanocomposite membrane was fabricated and first used to mode lock a fiber laser, and stable mode-locked solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength have been directly generated from the laser.
Abstract: Due to its unique electronic property and the Pauli blocking principle, atomic layer graphene possesses wavelength-independent ultrafast saturable absorption, which can be exploited for the ultrafast photonics application. Through chemical functionalization, a graphene-polymer nanocomposite membrane was fabricated and first used to mode lock a fiber laser. Stable mode locked solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength have been directly generated from the laser. We show that graphene-polymer nanocomposites could be an attractive saturable absorber for high power fiber laser mode locking.
477 citations
TL;DR: In this article, an erbium-doped fiber laser passively mode-locked with atomic layer graphene was used to generate large energy pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs.
Abstract: We report on large energy pulse generation in an erbium-doped fiber laser passively mode-locked with atomic layer graphene. Stable mode locked pulses with single pulse energy up to 7.3 nJ and pulse width of 415 fs have been directly generated from the laser. Our results show that atomic layer graphene could be a promising saturable absorber for large energy mode locking.
452 citations
TL;DR: In this paper, a review of fiber laser technology as relevant for applications in ultrafast optics is given, focusing on systems built around passively mode-locked fiber lasers and fiber frequency combs, which are further amplified in large-core fiber amplifiers.
Abstract: In this paper, a review of fiber laser technology as relevant for applications in ultrafast optics is given. We discuss core enabling fiber technologies, such as fiber amplifiers, all-fiber dispersion control, and highly nonlinear and large-core fibers. We concentrate on systems built around passively mode-locked fiber lasers and fiber frequency combs, which are further amplified in large-core fiber amplifiers. Our review further encompasses coherent supercontinuum generation and techniques for absolute phase control of fiber lasers and amplifiers. Applications concerned with spectral generation in the range from the vacuum UV to the terahertz range are also described.
340 citations
TL;DR: In this article, fundamental measurements of the properties of thulium-doped silica and power scaling studies of fiber lasers based on the material were described. But the results were limited to the case of a 25mum-diameter, 0.08 numerical aperture (NA) core.
Abstract: We describe fundamental measurements of the properties of thulium (Tm)-doped silica and power scaling studies of fiber lasers based on the material. Data on the high-lying Tm:silica energy levels, the first taken to our knowledge, indicate that pumping at 790 nm is unlikely to lead to fiber darkening via multiphoton excitation. Measurement of the cross-relaxation dynamics produces an estimate that, at the doping levels used, as much as 80% of the decay of the Tm level pumped is due to cross relaxation. Using a fiber having a 25-mum-diameter, 0.08 numerical aperture (NA) core, we observed fiber laser efficiencies as high as 64.5% and output powers of 300 W (around 2040 nm) for 500 W of launched pump power, with a nearly diffraction-limited beam. At these efficiencies, the cross-relaxation process was producing 1.8 laser photons per pump photon. We generated 885 W from a multimode laser using a 35-mum, 0.2-NA core fiber and set a new record for Tm-doped fiber laser continuous-wave power.
317 citations
JILA1
TL;DR: A high-power optical-parametric-oscillator (OPO) based frequency comb in the mid-IR wavelength region that employs periodically poled lithium niobate and is singly resonant for the signal is presented.
Abstract: We present a high-power optical-parametric-oscillator (OPO) based frequency comb in the mid-IR wavelength region. The system employs periodically poled lithium niobate and is singly resonant for the signal. It is synchronously pumped by a 10 W femtosecond Yb:fiber laser centered at 1.07 microm. The idler (signal) wavelength can be continuously tuned from 2.8 to 4.8 microm (1.76 to 1.37 microm) with a simultaneous bandwidth as high as 0.3 microm and a maximum average idler output power of 1.50 W. We also demonstrate the performance of the stabilized comb by recording the heterodyne beat with a narrow-linewidth diode laser. This OPO is an ideal source for frequency comb spectroscopy in the mid-IR.
311 citations
TL;DR: It is shown that apart from the conventional dissipative Soliton operation, an all-normal-dispersion fiber laser can also emit square-profile dissipative solitons whose energy could increase to a very large value without pulse breaking.
Abstract: We report on the generation of 281.2 nJ mode locked pulses directly from an erbium-doped fiber laser mode-locked with the nonlinear polarization rotation technique. We show that apart from the conventional dissipative soliton operation, an all-normal-dispersion fiber laser can also emit square-profile dissipative solitons whose energy could increase to a very large value without pulse breaking.
305 citations
TL;DR: In this paper, the accuracy of a frequency comb with the ease of use of a tunable, external cavity diode laser is demonstrated, enabling precise dispersion measurements of microresonator modes.
Abstract: Spectroscopy that combines the accuracy of a frequency comb with the ease of use of a tunable, external cavity diode laser is demonstrated, enabling precise dispersion measurements of microresonator modes.
280 citations
TL;DR: In this article, the authors review rare-earth-doped chalcogenide fiber for mid-and long-wave IR lasers, and highly nonlinear chalgogenide fibers and photonic crystal fiber for wavelength conversion in the mid and longwave IR.
Abstract: The Naval Research Laboratory (NRL) is developing chalcogenide glass fibers for applications in the mid-and long-wave IR wavelength regions from 2 to 12 mum. The chalcogen glasses (i.e., glasses based on the elements S, Se, and Te) are transparent in the IR, possess low phonon energies, are chemically durable, and can be drawn into fiber. Both conventional solid core/clad and microstructured fibers have been developed. Chalcogenide glass compositions have been developed that allow rare earth doping to enable rare-earth-doped fiber lasers in the IR. Also, highly nonlinear compositions have been developed with nonlinearities ~1000times silica that enables nonlinear wavelength conversion from the near IR to the mid-and long-wave IR. In this paper, we review rare-earth-doped chalcogenide fiber for mid-and long-wave IR lasers, and highly nonlinear chalcogenide fiber and photonic crystal fiber for wavelength conversion in the mid-and long-wave IR.
TL;DR: In this paper, the results of investigations of Bi-doped fiber lasers covering a wavelength range of 1150 -1550 nm are presented. And the luminescence properties of various Bi-Doped glasses are discussed.
Abstract: The recent results on the new laser material – Bi-doped glasses and optical fibers are reviewed. First, luminescence properties of various Bi-doped glasses are discussed. At last the results of investigations of Bi-doped fiber lasers covering a wavelength range of 1150 – 1550 nm are presented.
TL;DR: In this article, a high-power optical parametric oscillator-based frequency comb was proposed for the mid-infrared wavelength region using periodically poled lithium niobate.
Abstract: We present a high-power optical parametric oscillator-based frequency comb in the mid-infrared wavelength region using periodically poled lithium niobate. The system is synchronously pumped by a 10-W femtosecond Yb:fiber laser centered at 1.07 um and is singly resonant for the signal. The idler (signal) wavelength can be continuously tuned from 2.8 to 4.8 um (1.76 to 1.37 um) with a simultaneous bandwidth as high as 0.3 um and a maximum average idler output power of 1.50 W. We also demonstrate the performance of the stabilized comb by recording the heterodyne beat with a narrow-linewidth diode laser. This OPO is an ideal source for frequency comb spectroscopy in the mid-IR.
TL;DR: A good qualitative agreement is demonstrated between experimental results and numerical modeling based on modified nonlinear Schrödinger equations in the noise-like pulse generation regime.
Abstract: We observed generation of stable picoseconds pulse train and double-scale optical lumps with picosecond envelope and femtosecond noise-like oscillations in the same Yb-doped fiber laser with all-positive-dispersion cavity mode-locked due to the effect of non-linear polarization evolution. In the noise-like pulse generation regime the auto-correlation function has a non-usual double (femto- and picosecond) scale shape. We discuss mechanisms of laser switching between two operation regimes and demonstrate a good qualitative agreement between experimental results and numerical modeling based on modified nonlinear Schrodinger equations.
TL;DR: A 24 W liquid-cooled CW 3 microm fiber laser with a multimode-core Er-doped ZBLAN fiber with stable high-power operation was demonstrated, and this is the highest output power obtained by a 3 micron fiber laser.
Abstract: A 24 W liquid-cooled CW 3 microm fiber laser with a multimode-core Er-doped ZBLAN fiber has been developed. The output power of 24 W and an optical-to-optical efficiency of 14.5% (with respect to incident pump power) were obtained with 975 nm diode pumping. Efficient cooling was implemented by a combination of fluid cooling over the entire length of the fiber and conductive cooling at both end faces of the fiber. Consequently, stable high-power operation was demonstrated. To our knowledge, this is the highest output power obtained by a 3 microm fiber laser. Furthermore, the high power can be further scaled up, since the output power in the present work is limited only by the available pump power.
TL;DR: The novel fabrication method of the polymer-free absorber and device parameters determined using nonlinear reflectivity measurement are described in detail and the observed operation bandwidth of approximately 1 microm is the broadest reported to date for a single carbon nanotube-based saturable absorber.
Abstract: Mode-locked sub-picosecond operation of Yb-, Er- and Tm:Hodoped fiber lasers operating at 1.05 microm, 1.56 microm and 1.99 microm, respectively, is demonstrated using the same sample carbon nanotube-based saturable absorber mirror. A mesh of single-walled carbon nanotubes was deposited on an Ag-mirror using a one-step dry-transfer contact press method to combine broadband saturable absorption and high reflectance properties. The novel fabrication method of the polymer-free absorber and device parameters determined using nonlinear reflectivity measurement are described in detail. To our knowledge the observed operation bandwidth of approximately 1 microm is the broadest reported to date for a single carbon nanotube-based saturable absorber.
TL;DR: In this article, the authors demonstrate optical frequency combs using the fluorite whispering gallery mode resonator as a nonlinear Kerr medium and two regimes of generation are observed, giving the record low repetition rate of 13 GHz, equal to the cavity's free spectral range (FSR) or high repetition rates of multiples of cavity FSR.
Abstract: We demonstrate optical frequency combs using the fluorite whispering gallery mode resonator as a nonlinear Kerr medium. Two regimes of generation are observed, giving the record low repetition rate of 13 GHz, equal to the cavity's free spectral range (FSR) or high repetition rates of multiples of cavity FSR. An intermediate regime was also observed. Raman lasing spectrum similar to modulation instability in fibers was observed for the first time to the best of our knowledge.
TL;DR: It is shown that depending on the strength of the cavity birefringence, stable single-, dual- and triple-wavelength DSs can be formed in the laser.
Abstract: We report on the generation of multi-wavelength dissipative soliton (DS) in an all normal dispersion fiber laser passively mode-locked with a semiconductor saturable absorber mirror (SESAM). We show that depending on the strength of the cavity birefringence, stable single-, dual- and triple-wavelength DSs can be formed in the laser. The multi-wavelength soliton operation of the laser was experimentally investigated, and the formation mechanisms of the multi-wavelength DSs are discussed.
TL;DR: A mode-locked fiber laser is reported that exploits dissipative-soliton pulse shaping along with cladding pumping for high average power and dechirped pulses at 70 MHz repetition rate.
Abstract: We report a mode-locked fiber laser that exploits dissipative-soliton pulse shaping along with cladding pumping for high average power. The laser generates 31 nJ chirped pulses at 70 MHz repetition rate, for an average power of 2.2 W. After dechirping outside the laser, 80 fs pulses, with 200 kW peak power, are obtained.
TL;DR: A novel and intriguing nonlinear dynamics observed in a fiber laser cavity is reported, in which soliton pulses are created from an extended noisy background and drift until they reach a condensed phase comprising several tens of aggregated solitons.
Abstract: We report a novel and intriguing nonlinear dynamics observed in a fiber laser cavity, in which soliton pulses are created from an extended noisy background and drift until they reach a condensed phase comprising several tens of aggregated solitons. This soliton flow can be adjusted with manual cavity tuning, and can even be triggered by the injection of an external low-power cw laser.
TL;DR: Stabilization of a thulium-holmium codoped fiber soliton laser with a saturable absorber based on carbon nanotubes with transform-limited 750-fs pulses with 0.5-nJ energy is reported.
Abstract: We report stabilization of a thulium-holmium codoped fiber soliton laser with a saturable absorber based on carbon nanotubes. The laser generates transform-limited 750-fs pulses with 0.5-nJ energy.
TL;DR: A chain of four Tm-doped fibers amplified a single-frequency, 2040 nm diode laser to 608 W with M(2)=1.05+/-0.03, to be known as the highest power obtained from any single- frequencies, single-mode fiber laser.
Abstract: A chain of four Tm-doped fibers amplified a single-frequency, 2040 nm diode laser to 608 W with M2=1.05±0.03, limited by available pump power. Stimulated Brillouin scattering limits were investigated by splicing different lengths of passive fiber to the output of the final amplifier stage. Integrated rms phase noise above 1 kHz was less than λ/30, suggesting the possibility of further scaling via coherent beam combining. To our knowledge, this is the highest power obtained from any single-frequency, single-mode fiber laser.
TL;DR: In this paper, the authors present theoretical and experimental research on coherent beam combining of fiber amplifiers using stochastic parallel gradient descent (SPGD) algorithm and demonstrate the feasibility of beam combining using SPGD algorithm analytically.
Abstract: We present theoretical and experimental research on coherent beam combining of fiber amplifiers using stochastic parallel gradient descent (SPGD) algorithm. The feasibility of coherent beam combining using SPGD algorithm is detailed analytically. Numerical simulation is accomplished to explore the scaling potential to higher number of laser beams. Experimental investigation on coherent beam combining of two and three W-level fiber amplifiers is demonstrated. Several application fields, i.e., atmosphere distortion compensating, beam steering, and beam shaping based on coherent beam combining using SPGD algorithm are proposed.
TL;DR: This is the first demonstration of mode-locked 2 mum fiber laser using shorter than 1-m-long active fiber, which paves the way for the demonstration ofmode-locked fiber laser at 2 mum with gigahertz fundamental repetition rate.
Abstract: We report self-starting passively mode-locked fiber lasers with a saturable absorber mirror using a piece of 30-cm-long newly developed highly thulium (Tm)-doped silicate glass fibers. The mode-locked pulses operate at 1980 nm with duration of 1.5 ps and energy of 0.76 nJ. This newly developed Tm-doped silicate fiber exhibits a slope efficiency of 68.3%, an amplified spontaneous emission spectrum bandwidth (FWHM) of 92 nm, and a gain per unit length of greater than 2 dB/cm. To the best of our knowledge, it is the first demonstration of mode-locked 2 μm fiber laser using shorter than 1-m-long active fiber, which paves the way for the demonstration of mode-locked fiber laser at 2 μm with gigahertz fundamental repetition rate.
TL;DR: A spectrally asymmetric resonator 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%.
Abstract: We report a more than 150 W spectrally-clean continuous wave Raman fiber laser at 1120 nm with an optical efficiency of 85%. A ~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%.
Patent•
16 Nov 2009TL;DR: The molar ratio between the ytterbium-doped optical fiber core and the cladding is 0.09 to 0.68 molester percent as mentioned in this paper.
Abstract: An ytterbium-doped optical fiber of the present invention includes: a core which contains ytterbium, aluminum, and phosphorus and does not contain germanium; and a cladding which surrounds this core. The ytterbium concentration in the core in terms of ytterbium oxide is 0.09 to 0.68 mole percent. The molar ratio between the phosphorus concentration in the core in terms of diphosphorus pentoxide and the above ytterbium concentration in terms of ytterbium oxide is 3 to 30. The molar ratio between the aluminum concentration in the core in terms of aluminum oxide and the above ytterbium concentration in terms of ytterbium oxide is 3 to 32. The molar ratio between the above aluminum concentration in terms of aluminum oxide and the above phosphorus concentration in terms of diphosphorus pentoxide is 1 to 2.5.
TL;DR: In this article, the authors demonstrate the use of a fiber-based femtosecond laser locked onto an ultrastable optical cavity to generate a low-noise microwave reference signal.
Abstract: We demonstrate the use of a fiber-based femtosecond laser locked onto an ultrastable optical cavity to generate a low-noise microwave reference signal. Comparison with both a cryogenic sapphire oscillator (CSO) and a titanium-sapphire-based optical frequency comb system exhibit a stability of about 3×10−15 between 1 and 10 s. The microwave signal from the fiber system is used to perform Ramsey spectroscopy in a state-of-the-art cesium fountain clock. The resulting clock is compared to the CSO and exhibits a stability of 3.5×10−14τ−1/2.
Patent•
17 Mar 2009
TL;DR: In this paper, an ultrashort pulse laser system may include at least one of a fiber amplifier or fiber laser, with pulse widths up to a few nanoseconds.
Abstract: Various embodiments may be used for laser-based modification of target material of a workpiece while advantageously achieving improvements in processing throughput and/or quality. Embodiments of a method of processing may include focusing and directing laser pulses to a region of the workpiece at a pulse repetition rate sufficiently high so that material is efficiently removed from the region and a quantity of unwanted material within the region, proximate to the region, or both is reduced relative to a quantity obtainable at a lower repetition rate In at least one embodiment, an ultrashort pulse laser system may include at least one of a fiber amplifier or fiber laser. Various embodiments are suitable for at least one of dicing, cutting, scribing, and forming features on or within a semiconductor substrate. Workpiece materials may also include metals, inorganic or organic dielectrics, or any material to be micromachined with femtosecond and/or picosecond pulses, and in some embodiments with pulse widths up to a few nanoseconds.
TL;DR: It is suggested that the coexistence of the redox couple Ce(3+)/Ce(4+) in the glass provides means for trapping both hole- and electron-related color centers that are responsible for the induced optical losses in Yb-doped fiber lasers.
Abstract: We show that the photodarkening resistivity of ytterbium-doped fiber lasers can be greatly improved by cerium codoping. It is suggested that the coexistence of the redox couple Ce(3+)/Ce(4+) in the glass provides means for trapping both hole- and electron-related color centers that are responsible for the induced optical losses in Yb-doped fiber lasers.
TL;DR: In this paper, the design of chromatic dispersions of highly nonlinear fibers for desired applications is discussed, and fabrication results, including HNLFs with a longitudinally uniform zero-dispersion wavelength or with optimized higher order dispersion, are presented.
Abstract: Silica-based highly nonlinear fibers (HNLFs) have been utilized as platforms for various applications, including fiber lasers, optical amplifiers, and optical signal processings. For the practical applications, nonlinearity enhancement without degrading the attenuation and tailoring the chromatic dispersions remain the key issues. Herein, we initially discuss the design of chromatic dispersions of HNLFs for desired applications. Then the fabrication results, including HNLFs with a longitudinally uniform zero-dispersion wavelength or with optimized higher order dispersion, are presented. Furthermore, using evolved HNLFs, we demonstrate a unique four-wave-mixing-based wavelength conversion. In addition, suppression of the stimulated Brillouin scattering, a critical issue for high-power applications, is discussed. We fabricate Al2O3-doped HNLF that has lower Brillouin gain by 6.1 dB as compared with that of conventional GeO 2-doped HNLF.