Full-Open Cavity Multi-Wavelength Random Fiber Laser With Double Brillouin Frequency Spacing

A multi-wavelength Brillouin-Raman random fiber laser (BRRFL) with wavelength spacing of double Brillouin frequency shift (BFS) has been proposed for the first time, to the best of our knowledge. This BRRFL has an extremely simple full-open cavity configuration made up of only one roll of fiber, where bidirectional stimulated Raman/Brillouin scattering (SRS/SBS) and Rayleigh scattering based random distributed feedback coexist. In order to further enhance the performance of the BRRFL, a combination of erbium-doped fiber amplifier and single-mode fiber is incorporated into one side for random lasing regeneration. Both the side-mode suppression ratio (SSR) and order number of generated Brillouin Stokes lines (BSLs) show some improvements. A total of 66 BSLs with double BFS spacing has been obtained. Furthermore, the demonstrated laser system offers a wide tunable range with excellent flatness of spectral envelope. The proposed laser featuring simple structure and double BFS spacing would enable promising potentials in optical communication and sensing systems.