A tunable multi-wavelength Brillouin-erbium linear cavity fiber laser with higher optical signal to noise ratio

We experimentally demonstrated a widely tunable multi-wavelength Brillouin-erbium fiber laser by utilizing a double-pass pre-amplification Brillouin pump (BP) within a single-linear laser cavity. Owing to this pre-amplification technique, the laser can operate at low pump power and exhibit a low threshold operation of 35 mW pump power to create the first Stokes signal. By adjusting the polarization controller (PC), self-lasing cavity modes' oscillation can be tuned over 10 nm from 1562 nm to 1572 nm. We experimentally showed that the proposed novel fiber laser structure can achieve up to similar to 33 output channels with a constant wavelength spacing of 0.088 nm at 7.4 dBm of BP power and 250 mW of the 980 nm pump power by varying the wavelength of the BP and adjusting the PC. In addition, an average of 32 stable output channels could all be tuned over 12 nm with an average optical signal to noise ratio of 25 dB.