Self-Seeded Multiwavelength Dual-Cavity Brillouin-Erbium Fiber Laser

A self-seeded multiwavelength Brillouin-erbium fiber laser (BEFL) is demonstrated in dual-cavity system. The BEFL comprised of two matching ring-cavities of erbium-doped fiber (EDF) lasers combined through sharing of a 25-km-long single-mode fiber (SMF). The self-seeded signal in BEFL is initiated by the oscillating waves generated from EDFs which cause spontaneous scattering and backscattered Stokes wave in the fiber. Stimulated Brillouin scattering (SBS) is established by resonance interaction between backscattered Stokes wave and induced acoustic wave which will then act as Brillouin-pump to excite higher order Stokes lines. The forward propagating lasing signal in one cavity seeds backward Stokes wave in the other cavity and avalanched several higher order Stokes alternately through cooperative SBS and Rayleigh backscattering process in the SMF. High stability and repeatable of more than 67 Stoke lines with 0.088 nm line spacing was produced from 100 mW 980 nm-pump powers. The superimposed free-running oscillating frequencies from the EDF resonators produce stable gain bandwidth of 5.64 nm and it is vital in assisting the generation of multi-Stoke signals.