Ultra-narrow Linewidth Fiber Laser with Self-injection Feedback Based on Rayleigh Backscattering

摘要

A single longitudinal mode fiber laser with ultra-narrow linewidth based onself-injection feedback by using the linewidth compress mechanism of Rayleighbackscattering (RBS) are proposed and demonstrated. Since the linewidth of RBSis narrower than that of the incident light in optical fibers and they have thesame centre wavelength, the RBS can act as a mechanism to compress thelinewidth of the incident light in fiber ring laser. In addition, more RBSsignal could be collected to help further compress the laser linewidth besidesthe free spectral range is expanded when the self-injection feedback method isused. Our experimental results show that the side-mode suppression ratio of ourlaser is up to 75dB and the laser linewidth could be low to ~130Hz.