Cascaded gain fibers for increasing output power and the stimulated Brillouin scattering threshold of narrow linewidth fiber Raman amplifiers

J A Nagel; V Temyanko; J T Dobler; M E Likhachev; M M Bubnov; E M Dianov; N Peyghambarian

doi:10.1364/AO.55.004066

Cascaded gain fibers for increasing output power and the stimulated Brillouin scattering threshold of narrow linewidth fiber Raman amplifiers

Appl Opt. 2016 May 20;55(15):4066-72. doi: 10.1364/AO.55.004066.

Authors

J A Nagel, V Temyanko, J T Dobler, M E Likhachev, M M Bubnov, E M Dianov, N Peyghambarian

PMID: 27411133
DOI: 10.1364/AO.55.004066

Abstract

We show both experimentally and theoretically a method to increase the stimulated Brillouin scattering (SBS) threshold and output power of narrow linewidth fiber Raman amplifiers. This method employs two or more fibers with varying concentrations of the Raman gain material dopant such as GeO₂ or P₂O₅ in silicate-based glasses. These fibers are then cascaded to form an amplifier gain stage, disrupting the buildup of SBS that normally occurs in single continuous fibers. The numerical model shown is applicable to arbitrary amplifier systems for gain stage optimization and increased power scaling. We give experimental results for phosphosilicate fibers that agree well with simulation predictions that support the numerical model used.