Abstract

A new mechanism for passive Q-switching in fiber lasers based on cooperative dynamics of linear Rayleigh backscattering (RS) and Stimulated Brillouin Scattering (SBS) has been reported¹ recently. The matter of the mechanism is the following. Rayleigh backscattering of the light propagating in the laser cavity creates additional distributed feedback in the fiber cavity leading to a very effective linewidth narrowing. This in turn creates the conditions for SBS in the fiber. The growth of SBS then causes a series of avalanche processes leading to Q-switching. Until now, passive Q-switching caused by the above-mentioned mechanism has been realized experimentally but with pump powers higher than 2 W^1,2. At so high pump levels, the taser dynamics is complicated by a multiplicity of competing nonlinear effects impeding both the recogrution of initial RS-SBS process leading to Q-switching and comparison of experimental and theoretical results.

© 2000 IEEE