Tunable Brillouin-Erbium Comb Fiber Laser in a Linear Cavity With a Single-Mode Tellurite Fiber

We demonstrate a Brillouin-erbium fiber laser in a linear cavity with a single-mode tellurite fiber. Only 132-m tellurite fiber is used in the cavity because of the high Brillouin gain coefficient. Both the backward and forward Brillouin lines are reflected into the cavity, which experience dual-pass Brillouin gain. With a tunable filter, the gain is equalized in the erbium-doped fiber bandwidth. About 40 comb lines spaced by 7.91 GHz are obtained and the line number is kept in the tunable range from 1528 to 1565 nm with 37 nm. The average output power fluctuates from 44 to 48 mW in the tunable range.