Dynamics of ultimate spectral narrowing in a semiconductor fiber-grating laser with an intra-cavity saturable absorber

Abstract

The ultimate spectrum-narrowing and side-mode suppression due to the presence of a saturable absorber in an external cavity of a fiber Bragg grating semiconductor laser is numerically simulated. The proposed algorithm describes an effect of absorption bleaching in a saturable absorber using earlier measurements and shows the evolution of a dynamic grating in the laser cavity. The simulations confirm for the first time an empirical theory of spectral line narrowing in a laser with an intra-cavity saturable absorber.