Tunable narrow linewidth and stable frequency laser based on stimulated Rayleigh scattering in non-uniform optical fiber

Abstract

A novel tunable and stable frequency fiber laser with ~4 kilohertz linewidth based on stimulated Rayleigh scattering (STRS) in non-uniform optical fiber by using a broadband light source and a tunable filter is proposed in this paper for the first time to our knowledge without ring laser configuration. Because of the variable core size and dispersion along the fiber for non-uniform optical fiber, the threshold value of stimulated Brillouin scattering (SBS) was increased by ~7 dB; hence the phenomena of STRS can be clearly demonstrated. The frequency stability of the tunable laser only depends on the tunable filter because the frequency of Rayleigh scattering in optical fiber is not sensitive to the change of environmental conditions. Such kind of narrow tunable laser sources could find widely applications in optical communication, optical sensing, optical precision metrology, and high-resolution spectroscopy.