Dual-cavity Brillouin/erbium fiber laser for DWDM

We report on the operation of a multiple wavelength dual-cavity Brillouin/erbium fiber laser (BEFL) that could output a 22 GHz comb of 2×15 channels. The all-fiber laser system consists of two erbium-doped fiber ring lasers (EDFL) that share a single mode fiber (SMF) to produce interdependent bidirectional Stokes signals. The system configuration was made such that there is a slightly higher cavity loss incurred in one the cavities and results in a small wavelength-shift in the EDFL peak gain of the cavity. Coupling of these cavities leads to a slightly broader spectrum peak from the superimposing of the two free-running EDFL spectra and this would increase the number of Stokes lines when Brillouin pump is injected into the SMF. The dual cavity BEFL system produces a stable output of 22-GHz (0.18 nm) comb of 2×15 channels at 1560 nm that can be used for dense wavelength division multiplexed (DWDM) systems