An amplified distributed feedback fiber laser for distributed and interference sensing

Abstract

A narrow linewidth laser composed of an Erbium doped distributed feedback fiber laser (DFB-FL) and an all-single-mode-fiber amplification structure is proposed. The cavity of the DFB-FL is a phase-shifted grating in the Erbium doped fiber and fabricated by ultraviolet laser inscribing and phase mask dithering. A master oscillator power amplifier in all-single-mode-fiber structure is pumped by the residual pump laser from the DFB-FL. The amplified distributed feedback fiber laser with a 57dB signal-to-noise ratio has a linewidth of 2 kHz with low phase noise. The systematic tests about laser linewidth and phase noise are carried out. The results show that these characteristics are comparable to other commercial narrow linewidth laser products. As a stable narrow linewidth laser source, it is attractive and useful in applications in the distributed sensing and the interference sensing fields.