Study on highly stable single-frequency Brillouin fiber laser

Abstract

Single-frequency Brillouin fiber lasers (SF BFLs) have been attracting extensive interests because of their compact- ness, stableness and their characteristics of linewidth narrowing and noise suppression. They have important potential applications in many fields, such as fiber sensing systems, high-resolution spectroscopy and microwave photonics, and so on. In this paper, we demonstrated the SF BFL using the tunable laser source (TLS) as the Brillouin pump. When the cavity length is cut short to 10.3 m and the FSR is 20.1 MHz being comparable to the Brillouin gain linewidth, the BFL begins to operate in single-longitudinal-mode. The laser has the out power conversion efficiency of 42.5% and intensity fluctuation bellow 4%. The SF BFL’s signal to noise ratio (SNR) is 10 dB greater than the TLS. Also, the laser has good performance for suppressing the noise and the linewidth of which is measured to be below 5 kHz.