Thulium-doped fiber random laser by using randomly-spaced fiber Bragg grating array

A thulium-doped fiber random laser by using a randomly-spaced fiber Bragg grating array as the feedback media is proposed. It possesses a half-open cavity structure formed with a highly reflective fiber Bragg grating and is pumped with a 793 nm laser diode. Stable random lasing at 1944.9 nm with threshold power of 0.69 W is achieved.

I. Introduction

Random fiber lasers (RFLs) possess special characteristics including relatively simple technology (no need to build precise cavities), and low spatial or temporal coherence. They have been widely studied in recent years and show good potentials in various applications such as sensing, parallel imaging and microscopy [1]–[4]. However, most RFLs are based on backward Rayleigh scattering effect in single-mode fibers. The scattering coefficient is very low so long-distance fiber up to tens of km is usually required [5]–[9]