Analysis of single frequency Raman amplifier for guide star application

We present theoretical and experimental results on the scalability of amplifying a single-frequency diode laser operating at 1178 nm through the utilization of a core pumped Raman fiber amplifier. A model that accounts for stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in both co-pumped and counter-pumped configurations is developed. In order to mitigate the SBS process, a multi-step temperature distribution that is spatially optimized along the length of fiber is investigated numerically. We also present preliminary experimental results on a co-pumped Raman amplifier with an output power of 12 W and a measured Brillouin gain coefficient of approximately 1.2×10-11 m/W.