Comprehensive Investigation on the Role of Temporal Property of Pump Laser in a Single-Frequency Raman Fiber Amplifier

Based on a single-frequency Raman fiber amplifier (RFA) operating at 1120 nm pumped by different laser oscillators at 1070 nm, the role of a temporal property of pump laser in a single-frequency RFA is investigated in detail. The pump lasers with different temporal properties are achieved by varying the bandwidth of the low reflectivity grating that consist of the laser cavity. The experimental results show that a copumped single-frequency RFA could provide a well platform to reflect the intensity stability of the pump laser, and the optical-to-optical conversion efficiency of the RFA varies with the intensity stability of the pump laser. On the other side, the optical-to-optical conversion efficiency of the counter-pumped RFA is independent of the intensity stability of the pump laser. Nevertheless, the intensity stability of the signal laser would be affected by the intensity stability of the pump laser. The experimental results are theoretically analyzed by using our spectral evolution model. Theoretical results are consistent well with the experimental ones, which also reveal that low-noise RFA could be achieved by using intensity stable pumping.