Influence of a bidirectional recycling residual pump on the Stokes signal characteristics of a linear cavity Brillouin fiber laser

Abstract

The effect of a bidirectional recycling residual pump on the Brillouin Stokes signal threshold, as well as on its power, is experimentally investigated. The laser cavity is formed with two optical mirrors as the resonator reflectors which allow bidirectional residual pump recycling that causes bidirectional Brillouin gains. These gains significantly reduce the threshold power and increase the Stokes signal power. For the same single mode fiber length, the Brillouin Stokes signal threshold is reduced by up to 75% and 50% in the laser structure compared to its values in conventional and recycling Brillouin threshold reduction techniques, respectively. In addition, the effect of Brillouin gains on the Stokes signal power is illustrated and exhibits no additional gain in the laser cavity as compared with the recycling technique, especially for long fibers >8 km. © 2013 Astro Ltd.