Gain enhancement of fiber optical parametric amplifier via introducing phase-shifted fiber Bragg grating for phase matching

Abstract

The gain enhancement properties of a fiber optical parametric amplifier (FOPA) are investigated by inserting a phase-shifted fiber Bragg grating (PS-FBG) between two highly nonlinear dispersion shift fibers (HNL-DSFs). The PS-FBG is adopted to reduce the power and change the phase of the idler wave, and thus to change the phase mismatch parameter and relative phase difference among the four involved waves in four-wave mixing (FWM). The influence of reflectivity and phase shift of the PS-FBG on the gain properties of FOPA is focused on. It is shown that, with the introduction of PS-FBG, the gain of FOPA is enhanced significantly. With the increase of reflectivity of PS-FBG, the gain increases first and reaches its maximum at the optimal reflectivity. Besides, the π-phase shift contributes to the highest gain of FOPA. The effect of insertion loss is also considered. The FOPA with PS-FBG provides a new tool to obtain gain enhancement, which is extremely useful for the optical communication system.