We demonstrate a novel amplification regime in counter-pumped, relatively long (2 meters), large mode area, highly Yb-doped and polarization-maintaining tapered fiber, which offers high peak power directly from the amplifier. The main feature of this is that amplifying signal propagates through thin part fiber without experiences an extremely gain thick where most pump absorbed. In regime, we have demonstrated 8 ps pulse to up 0.76 MW, limited by appearance stimulated Raman scattering. same...

We report the spatiotemporal mode-locked multimode fiber laser operating at 1.55 µm based on semiconductor saturable absorber mirrors with mode-locking threshold as low 104 mW. Benefiting from interference filtering effect introduced in cavity not only central wavelength can be continuously tuned 1557 nm to 1567 nm, but also number of output pulses adjusted 1 4 by simply adjusting polarization controllers. This work provides a new platform for exploring dynamic characteristics negative...

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...

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...

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...

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.

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 region for high-order mode content to be carefully controlled. A ratio of diameter overall core 40% allows emission, even small spool diameters 15 cm. Such a was manufactured subsequently used as element cw oscillator. good beam quality parameter M(2)=1.12 slope efficiency 80%...

A design of a polarizing all-glass Bragg fiber with microstructure core has been proposed for the first time. This provides suppression high-order modes and one polarization states fundamental mode. The was fabricated by new, simple method based on combination modified chemical vapor deposition (MCVD) process rod-in-tube technique. mode field area found to be about 870 μm² near λ=1064 nm. extinction ratio better than 13 dB observed over 33% wavelength range (from 1 1.4 μm) after propagation...

For the first time, to best of our knowledge, we present an all-fiber polarization-maintaining passively mode-locked picosecond laser operated at 980 nm. The cavity had a ring configuration with semiconductor saturable absorber mirror as mode-locking element. As active medium, used specially designed cladding-pumped Yb-doped fiber reduced cladding-to-core diameter ratio. was self-starting and in net normal dispersion regime, where spectral profile gain medium acted filter By intracavity...

Photochemical reactions induced in the glass network of an ytterbium-doped fibre core by IR laser pumping and UV irradiation have been investigated analysing absorption luminescence spectra. We performed comparative studies photoinduced spectra preforms differing composition: Al2O3 : SiO2, Yb2O3 P2O5 SiO2. The unirradiated preform samples show strong bands peaking at 5.1 6.5 eV, whose excitation plays a key role colour centre generation network. 'Direct' 5.1- 6.5-eV 244 193 nm leads to...

We present multimode fiber lasers for tandem pumping of high power Er-, Tm-, and Yb-doped lasers. These pump sources are based on especially developed Er- double-clad fibers. Er-doped with record conversion efficiency >48% at 1565 nm more than 41% 1535 1590 were realized. laser 1020 85% was demonstrated. Also, we propose novel design compact cost-effective scheme. The potential scaling proposed to the 1-10-kW level their advantages as resonant discussed.

Abstract The spectral window around 1700 nm is interesting for in-depth multiphoton microscopy of intact tissues due to reduced scattering and absorption in this wavelength range. However, wide adoption excitation range will rely on the availability robust cost-effective high peak power pulsed lasers operating at these wavelengths. Here, we report a fiber-based femtosecond laser providing up 95 nJ, 85 fs pulses 1800 nm. system makes use chirped pulse amplifier emitting 1560 followed by an...

We proposed and investigated a novel type of all-glass hybrid fiber where light is confined in the low-index core due to both total internal reflection coherent Fresnel (a photonic bandgap mechanism). The mode has an anomalous dispersion 13 ps/(nm km) at 1064 nm low loss (~6 dB/km), it can be easily excited by splicing with single-mode step-index fiber. compression positively chirped 8 ps pulses down 330 fs was demonstrated fabricated

Abstract We proposed and experimentally demonstrated a technique for the suppression of unwanted modes in double-clad fibers with high core-to-clad diameter ratio by introducing high-index absorbing inclusions into first cladding fibers. These disturb shape undesirable modes, noticeable part power becomes localized inside inclusion, resulting an increase propagation loss these modes. Two fiber designs were studied realized: one cylindrical symmetry ring as inclusion another rods inserted...

Abstract We have developed and demonstrated a polarisation-maintaining single-mode ytterbium-doped fibre for light amplification at wavelength near 0.976 μm in an all-fibre configuration. A distinctive feature of the proposed design is low losses due to fusion splices with standard having core diameter 10 μm, which has made it possible produce small-signal amplifier gain threshold 3 W differential pump-to-signal conversion efficiency 9.8 % saturation regime. The been shown be well-suited...

In this paper, we present a novel single-mode Yb-doped fiber with 14 µm core and 45 cladding diameter. A 976 nm all-fiber high-power amplifier was manufactured based on fiber. 10-mm-long taper used to launch the pump light, guidance of high NA provided by glass-air interface. 13 W output power limited only available achieved 31% slope efficiency.

A novel Yb-doped fiber design for improved lasing near 976 nm based on spectral filtering of the amplified spontaneous emission 1030 was realized and investigated. very sharp short-pass filter implemented by adding appropriately chosen high-index absorbing rods into silica cladding. In this case, resonant interaction core mode with rod could be controlled bending, which allows precise adjustment stop-band position. It shown that utilization Sm-doped one to achieve high absorption at unwanted...

We have studied absorption spectra of optical fibres doped with rare-earth ions (Sm3+, Tm3+, Tb3+, Pr3+ and Ho3+) demonstrated that they are potentially attractive for ensuring wavelength-selective in fibre lasers. Such can be used pump diode protection against back-reflected light at the operating wavelength neodymium, erbium, erbium – ytterbium or thulium A proper choice a element makes it possible to ensure strong (10 20 dB) laser combination high transmission (loss under few tenths...

A new figure-eight mode-lock laser design based on a passive nonlinear loop mirror with small modulation depth has been proposed. Self-started narrow-linewidth nanosecond-pulse lasers are realized: one is polarization-insensitive components (with polarization controller) and the other an environmentally stable adjustment-free polarization-maintaining components. In both cases, generate rectangular-shaped pulses. The duration of pulses can be continuously adjusted from sub-nanosecond to more...

We have proposed and demonstrated an approach for ensuring quasi-single-mode operation of a cylindrically symmetric hybrid fibre having anomalous dispersion at wavelengths around 1 μm. Basic to this are distinctions between spatial mode distributions the use high-loss ring layer in region minimum electric field operating mode.

Solitonic effects, including multi-solitonic fission and subsequent self-frequency shift, are used to tailor ultrashort (sub-100 fs) pulses with carrier wavelength broadly tunable in spectral regions between fixed laser lines. Although high-energy can be obtained stiff waveguides, the benefit of pulse delivery through bends is lost. Here, we report on generation, sustained propagation, large frequency shift megawatt-class all-silica antiresonant fibers ultra-large mode area. We designed...

A cladding-pumped all-fiber chirped femtosecond pulse Yb-doped mode-locked laser operating near 977 nm was demonstrated for the first time. Nonlinear polarization evolution used as mode-locking mechanism. The self-starting and extremely stable (the stability of repetition rate 41.6 MHz better than that 15 Hz). Amplification achieved using a specially designed fiber. main feature current design its increased intracavity nonlinearity, which resulted in strong self-phase modulation significant...