A method for fabrication of a novel type optical fiber with dispersion varying along the length is described. The takes into account calculated dependence on core diameter measured profile preform and desirable length. main parameters drawn are theoretically studied experimentally measured. fibers great interest nonlinear optics. Such applications fibers, such as high-quality soliton pulse compression, pulsewidth stabilization through compensation losses, generation high-repetition-rate...

Cascaded lasing provided by Raman gain (at 1115-nm pumping) and random distributed feedback (via Rayleigh backscattering) in a 1.65-km phosphosilicate fiber is studied. Output power for the second Stokes component (1398 nm) exceeds 5 W at pump of 11 W. In contrast to conventional cascaded laser with high-Q cavity intermediate first component, there no here losses, correspondingly. Longitudinal distribution shown be quite different also. As result, efficiency 2nd wave conversion not...

We describe the design and characterization of solid core large mode area bandgap fibers exhibiting low propagation loss bend loss. The have been prepared by modified chemical vapor deposition process. guidance obtained thanks to a 3-bilayer periodic cladding is assisted very slight index step (5.10-4) in core. reaches few dB/km found be close material

Heavily Er-doped fibers (EDFs) based on P2O5-Al2O3-SiO2 (PAS) ternary glass have been studied. A unique feature of this is the formation a AlPO4 join having structure similar to that SiO2 and refractive index below it. It found Er3+ absorption emission spectra in PAS EDFs are defined by dopant (Al2O3 or P2O5) present excess close those corresponding binary (Al2O3-SiO2 P2O5-SiO2). The presence results enhancement pump-to-signal conversion efficiency as compared with P2O5-SiO2 Al2O3-SiO2 (with...

We report, for the first time to our knowledge, on a single-mode millijoule-level 100-nanosecond Er-doped fiber laser operating near 1550 nm. The system features newly developed 35-μm-core Yb-free double-clad based P(2)O(5)-Al(2)O(3)-SiO(2) glass matrix and produces pulses with energy as high 1 mJ at repetition rates of 1-10 kHz.

Optimization of Yb-free Er-doped fiber for lasers and amplifiers cladding pumped at 976 nm was performed in this Letter. The single-mode design includes an increased core diameter 34 μm properly chosen erbium co-dopant concentrations. We demonstrate all-fiber high power laser amplifier based on with the record slope efficiency 40%. To best our knowledge, achieved output 75 W is highest reported such lasers.

The authors propose a new simple configuration for 1.24 and 1.48 µm Raman fibre lasers which are promising pumping sources 1.31 amplifiers Er-doped amplifiers, respectively. Efficient resonant conversion of CW 1.06 radiation to the first (1.24 µm) second (1.48 Stokes in phosphosilicate is demonstrated time.

We propose a novel saddle-shaped Yb-doped fiber design for high power generation in the spectral range near 0.976 μm. The has central single-mode part with core diameter of approximately 12 μm and an ultra-thin silica clad 49 At both ends fiber, core/clad diameters were adiabatically increased up to 20/80 be compatible ordinary passive fibers. A monolithic 976-nm continuous wave laser based on proposed was created. laser's record compared all-fiber schemes, output 10.6 W. Utilization...

We report a laser-diode-pumped 1407-nm Raman fiber laser with an output power of 1 W. In this three-cascaded cw laser, based on single active phosphorus-doped silica fiber, for the first time to authors' knowledge successive generation Stokes components essentially different frequency shifts (1330 and 490 cm-1) has been realized. These are associated both constituents (P2O5 SiO2) core glass.

We present an experimental demonstration of ultrafast all-optical thresholder based on a nonlinear Sagnac interferometer. The proposed design is intended for operation at very small phase shifts. Therefore, it requires in-loop nonlinearity lower than the classical loop mirror scheme. Only 15 meters conventional (non-holey) silica-based fiber used as element. polarization insensitive and good multi-wavelength operation, meeting all requirements autocorrelation detection in various optical...

An original architecture of an active fiber allowing a nearly diffraction-limited beam to be produced is demonstrated. The medium double-clad large-mode-area photonic-bandgap consisting 10,000 ppm by weight Yb(3+)-doped core surrounded alternation high- and low-index layers constituting cylindrical photonic crystal. periodic cladding allows the robust propagation approximately 200 microm(2) fundamental mode efficiently discriminates against high-order modes. M(2) parameter was measured 1.17....

In this paper, we present results on the amplification of 2 MHz linewidth nanosecond pulses in a recently developed ytterbium-free erbium-doped large mode area fiber cladding pumped at 980 nm. A record peak power 4 kW for single-frequency single-mode silica-based sources near 1550 nm is demonstrated. Pulse instabilities arising an all-fiber laser scheme from stimulated Brillouin scattering are described.

Prospects for average power scaling of sub-MW output peak picosecond fiber lasers by utilization a Yb-doped tapered at the final amplification stage were studied. In this paper, it was shown experimentally that allows achievement an level 150 W (limited available pump power) with 0.74 MW 22 ps pulses no signs transverse mode instability. Measurements content using S 2 technique showed negligible high order modes (less than 0.3%) in radiation even maximum level. Our reliability tests predict...

Silica-based optical fibers with an ultra-high Yb concentration were systematically studied. Three the most commonly used in industry glass matrixes for active fiber core investigated: aluminosilicate, phosphosilicate and aluminophosphosilicate. For all hosts doped a record high of fabricated utilizing all-gas-phase deposition based on MCVD technology. The factors limiting increase content glasses revealed. first time it was shown that highly Yb-doped could nearly completely lose their...

An all-fiber 1.48-mum generator based on a laser-diode-pumped Yb-doped double-clad laser and cascaded Raman wavelength converter has been developed. Second-order Stokes radiation was generated in phosphosilicate-fiber resonator formed by two pairs of Bragg gratings. A slope efficiency the 48% with respect to power emitted Yb achieved. We obtained an output 1 W at 34% laser-diode array power, total optical-to-optical 23%.

Radiation-induced absorption and lasing efficiency of a hermetically coated erbium-doped fiber saturated with molecular hydrogen are studied. It is shown that H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -loading fibers prolongs their service time in space more than 5 times, making such promising for applications.

With the aim to find best-suited host glass for radiation-resistant erbium-doped fibers (EDF), radiation-induced absorption (RIA) is measured and analyzed after γ -irradiation 3.0-4.5 kGy in 18 silica optical with various concentrations of dopants: Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , P xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> GeO Er . The RIA dependence on...

We report a new ytterbium-doped active tapered fibre used in the output amplifier stage of laser system for generation megawatt peak power ultrashort pulses microjoule energy range. The is single-mode at its input end (core and cladding diameters 10 ) multimode (diameters 45 ), but are amplified quasi-single-mode regime. Using hybrid Er/Yb comprising an erbium master oscillator wavelength near , nonlinear converter to range three-stage amplifier, we obtained duration, which were then...

The effect of ytterbium co-doping on erbium ion clustering in silica-based glass was studied. It experimentally shown that the pump-to-signal conversion efficiency could be significantly increased if number Yb3+ ions fiber core 20 times higher than Er3+ ions. Estimations clusters confirmed a decrease their at high Yb concentrations.

An all-glass Yb-doped single-mode fiber laser and amplifier with output power of more than 5 W near 977 nm have been realized. Both were based on a specially developed photodarking-free fibers increased core-to-clad diameter ratio (up to 0.31).

Single-mode Er–Yb fibers with the core based on a phosphorosilicate glass matrix (up to 6.5 mol.% P2O5) highly doped fluorine 0.9 wt.%) were fabricated using an all-gas-phase modified chemical vapor deposition method. The numerical aperture was in range of 0.07–0.08 relative pure silica, which allowed us increase single-mode diameter up 20 μm. slope efficiency lasers reached 34% launched pump power.

In this Letter, we propose and realize a novel concept for high-peak-power highly efficient fiber amplifier in the 1.55 µm spectral range. The is based on simultaneous utilization of Er-doped, Yb-free, Er-Yb codoped large-mode-area fibers spliced together. Using approach, demonstrate amplification single-frequency 160 ns pulses at 1554 nm to peak power 3.7 kW with pump-to-signal conversion efficiency 23.6% relative launched multimode pump 976 nm.

H-free and H-loaded pieces of a carbon-coated erbium-doped fiber (EDF) are gamma-irradiated to doses in the range 0.1-10 kGy. In three months after irradiation, optical loss spectra lasing efficiency fibers studied. It is found that slope laser based on an irradiated EDF quickly grows under action pumping at wavelength 980 nm, owing photobleaching radiation-induced color centers. Photobleaching be much more efficient H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

The optical properties of fibres with aluminophosphosilicate (APS) glass cores have been studied at Al2O3 and P2O5 concentrations varied independently from 0 to 20%, the ranges dopant that ensure an loss level acceptable for fabrication active established. origin increased losses observed previously in APS containing excess phosphorus pentoxide has identified, contamination source responsible such our eliminated.