1  kW peak power, 110  ns single-frequency thulium doped fiber amplifier at 2050  nm

Abstract

We report a high power, single frequency, linearly polarized master oscillator power amplifier emitting 110 ns, 1 kW peak power pulses at 2050 nm. A 20% slope efficiency and a beam quality of M2=1.21 are achieved with three-stage double-clad Tm(3+)-doped fiber architecture. Various pump schemes are compared leading to the conclusion that 793 nm pump wavelength is the most efficient for amplification at 2050 nm. Based on numerical simulations, the Brillouin gain coefficient around 2 μm in Tm(3+) highly doped silica fiber is estimated to 1.2×10(-11) m/W. Output peak power is limited by stimulated Brillouin scattering to 535 W without mitigation and to 1 kW with application of a strain distribution along the doped fiber.

High power pulsed fiber laser development for Co2 space based dial system

“…It is known that the central frequency of the lorentzian Brillouin gain curve can be shifted by applying strain to the fiber. Applying an optimal strain distribution for a given signal distribution in the fiber will result in a flat Brillouin spectrum and a larger threshold [6]. We have shown that a triangular distribution can be used.…”

Eyesafe high peak power pulsed fiber lasers limited by fiber nonlinearity

“…We developed a high power single-frequency laser source at 2050 nm using strain gradient to mitigate SBS [25]. The pumping scheme selected for the amplifier is clad pumping using 793 nm laser diodes.…”

“…The value of the Brillouin gain that we have discussed so far is the Brillouin gain value obtained for a homogenous fiber length L. Among the various methods used to increase the Brillouin threshold several are based on strain [15,25] or temperature [40][41][42] change along the fiber. The principle is to shift the Brillouin gain maximum along the fiber.…”

Simulation and design of a multistage 10W thulium-doped double clad silica fiber amplifier at 2050nm

“…A careful comparison of experiment and theory is important both for basic research and systematic engineering design of Thulium fiber amplifiers operating in the 2 µm region. Applications include LIDAR or spectroscopy, such as CO2 atmospheric absorption at 2051.4 nm 1 . Currently the state of modeling for Tm-doped fiber (TDF) amplifiers is not nearly as advanced as the state of modeling for Erbium-doped fiber amplifiers [2][3][4][5] .…”