Abstract

We report on a high power narrow linewidth ASE source at 1030 nm wavelength generated and amplified in a Yb-doped fiber based experimental setup. The presented ASE source is of high value for continuous-wave (cw) brightness enhancement techniques like spectral beam combination (SBC) [1] or even beam combination of phase locked broadband light sources [2]. In such systems narrow linewidth laser sources are commonly used but are eventually limited by nonlinear optical effects, especially when exceeding hundreds of Watts of output power. Usually, SBS and SRS are the prime nonlinearities limiting the performance of fiber based cw-operated systems. The appearance of SBS is much more likely for small bandwidth signals with high Q factor resonators and thus, one major problem for beam combining setups. Over the last years approaches to suppress SBS have been introduced and special acoustically anti-guiding fibers have been proposed [3]. Another proven method is the sinusoidal phase modulation to generate several side bands with a spectral distance in the 100 MHz range [4]. But even in this case the accentuated peaks of the side bands can trigger SBS. When using ASE light no longitudinal modes or sidebands are present and photons are equally distributed within the spectral shape making SBS most unlikely.

© 2011 Optical Society of America