Design of λ/4 phase shifted DFB fibre Raman laser

Abstract

The feasibility of building a distributed feedback fibre Raman laser based on a long uniform fibre Bragg grating was suggested by Perlin et al. [1]. However, such a laser requires good grating uniformity along a very long length, e.g. 1m, and has not been investigated experimentally. In this study, we demonstrated an improved design of a DFB fibre Raman laser with an optimised λ/4 phase-shifted grating structure, which enables highly efficient laser operation at low threshold with a relatively short cavity length.