Multi-wavelength Brillouin-erbium fiber laser with more than 95 lines based on a dual-ring structure

We demonstrate a multi-wavelength Brillouin fiber laser based on a dual-ring structure to take advantage of the forward and backward Brillouin gain simultaneously with an injected tunable scanning lasing. We used two erbium-doped fiber amplifiers for the amplification of the seed lasing and the operated Brillouin laser. The cascaded stimulated Brillouin effect in the section of dispersion-shifted fiber contributes to the free oscillation suppression in cavity. When the laser operates at the center wavelength of 1565 nm, the output spectra shows the maximum Brillouin lines of more than 95 with a wavelength spacing of about 0.08 nm under the maximum pump. Through adjusting of the seed wavelength and the tunable filter in cavity, the output spectra can be shifted from 1540 to 1570 nm. This fiber laser will find potential applications in optical measurement and sensing because of its large line number, stability, tunability and fixed wavelength spacing. (C) 2019 The Japan Society of Applied Physics