High-pulse energy extraction with high peak power from short-pulse eye safe all-fiber laser system

Abstract

All-fiber contained laser systems play a key role, in the development of rugged, compact, and highly efficient eye-safe laser sources that can generate high peak and average powers and short (<5 ns) pulses. Application of such laser systems include spectroscopy, LIDAR, free-space communications, materials processing and nonlinear optics. In this paper we present further improvement on a novel high power all-fiber-based master oscillator power amplifier (MOPA) laser system operating in the C-band with <5 ns pulses and a repetition rate range of 6kHz &#8722; 200kHz. The system was optimized for performance of repetition rates between 6kHz and 18kHz. With this system, pulse energies of 322 &#956;J with a peak power of 170kW and an average power of 1.9W were generated using a custom designed Er:Yb co-doped double-clad fiber. The spectral output of the amplified pulses shows no spectral broadening due to Four-Wave-Mixing or Stimulated Raman scattering for pulse energies with less than 260&#956;J. Additionally, a beam quality M²=2.1+/-0.1 was achieved. The physical performance parameters of the all-fiber laser system make it very suitable for a variety of applications. The performance of the MOPA system and the experimental data are presented and discussed. To our knowledge the combination of the presented pulses energies, peak power, average power are the highest ever recorded in an all fiber system.