High-energy pulsed operation of a Yb fibre master oscillator power amplifier with an amplified spontaneous emission light source

Abstract

We report high-energy pulsed operation of an amplified spontaneous emission (ASE) light source at 1050 nm based on a Yb-doped fiber master oscillator power amplifier (MOPA). The ASE seed beam with a tailored spectral bandwidth was temporally modulated by an acoustooptic modulator and was amplified in three Yb fiber amplifier stages. The MOPA yielded 320.7 mu J and 415.0 mu J of the pulsed outputs at a 100 kHz repetition rate for the ASE seeds with 1 nm and 2 nm bandwidths, respectively. Investigation of stimulated Brillouin scattering (SBS) in Yb fibers showed that ASE light pulses could offer a higher pulse energy than laser pulses due to the higher SBS threshold. We will discuss the prospects of further power scaling in a fiber ASE light source with a broad bandwidth by overcoming the SBS limitation.