1,721,006 research outputs found
High power fibre lasers: fundamentals, recent progress and challenges
No full textWe review the fundamental properties and latest power scaling in fibre lasers, including limitations imposed by fibre nonlinearities, transverse modal instabilities and other parasitic effects. Their impact on the industrial applications space is also considered
High-brightness pulsed cladding-pumped Raman fibre source at 1660 nm
No full textWe report the first demonstration of a pulsed single-stage cladding-pumped Raman fiber source which is capable of delivering up to 10 µJ diffraction-limited pulses at 1660 nm. The pulses are 620 ns long with a peak power near 16 W and the pump to signal conversion efficiency is about 36 %
Tandem pumping of large-core double-clad Ytterbium-doped fiber for control of excess gain
No full textWe explain and experimentally verify how to control unwanted excess gain of higher-order modes in cladding-pumped large-core ytterbium-doped fiber amplifiers through high-brightness tandem-pumping with wavelengths close to the signal wavelength
UK industrial high-power fiber lasers
No full textWe report on a 2kW GTWave single mode fibre laser with low SRS level, and discuss power scaling challenges where both SRS level and TMI must be mitigated
High-power tunable single-frequency single-mode erbium:ytterbium codoped large-core fiber master-oscillator power amplifier source
No full textWe present a cladding-pumped single-frequency, single-mode erbium:ytterbium co-doped fiber master-oscillator power amplifier source generating up to 151 W of continuous-wave output power at 1563 nm with 33% slope efficiency and 20 dB gain. This source was also tunable and had a stable operation range of 1546 to 1566 nm at an output power level in excess of 125 W. The doped fiber exploited a large-core design for improved power handling and mitigation of stimulated Brillouin scattering. There was no sign of having stimulated Brillouin scattering even at the highest power. Despite a large core (V = 12), the output beam was nearly diffraction-limited (M = 1.1). The source showed slight roll-over at over 100 W of output power because of the onset of emission from ytterbium, centered at 1060 nm
Near-diffraction-limited supercontinuum generation in a cladding-pumped nonlinear fiber converter
No full textThrough nonlinear scattering including stimulated Raman scattering and beam cleanup, a pulsed multimode pump beam is converted into a nearly diffraction-limited supercontinuum extending from 1 to 2 µm in a passive cladding-pumped nonlinear fiber converter
Design, performance, and limitations of fibers for cladding-pumped Raman lasers
No full textWe discuss designs of double-clad Raman fiber lasers for efficient 1st-Stokes generation. Limiting factors include unwanted 2nd Stokes generation, material damage, dispersion, inner-cladding NA, and background loss. A brightness enhancement of over 2000 is possible
Novel angle-resolved interrogation method for double-clad doped fibers and high-power fiber laser components
No full textWe present the novel use of a well-known angular interrogation method [1] for characterizing the absorption and loss of multimode doped fibers [2] and high-power fiber laser components, such as cladding mode-strippers [3]. Both meridional and skew rays can be excited by launching light at an angle to the axis of the fiber under test, as shown in the setup of Fig. 1(a). After propagating through the fiber under test, the power of the received light is measured with an integrating sphere that captures all angles. Fig. 1(c) shows the characterization of different cladding mode-strippers (MS). The reference fiber is a circular coreless fiber formed by low-loss synthetic silica glass and low-index polymer. It has a numerical aperture (NA) of ~0.44 and it is typically used for pump power delivery. MS#1 is less effective than MS#2 at attenuating both low- and higher-order cladding modes. The MS#2 results on the other hand, show that only light in the core (NA<0.1) remains, which is ideal for a cladding mode stripper
All-fibre 0.4 mJ high-coherence eye-safe optical source
No full textWe report a narrow-linewidth band (FWHM 0.4nm) optical pulsed OPA (master oscillator- power amplifier) source emitting 0.412mJ pulses 1.5kW peak power) in the eye-safe range (@1548nm). Pulse duration and repetition rate were 90ns and 5kHz respectively
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