Ultra-Wide Bandwidth Brillouin-Raman Random Fiber Laser With Augmented Synergistic Nonlinearity

We propose a Brillouin-Raman random fiber laser with enhanced synergistic nonlinearity for ultra-wide bandwidth Brillouin comb generation. The augmented synergistic nonlinearity, including enhanced Rayleigh scattering (RS) effect, stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS), is achieved in a hybrid fiber (a fiber combination of a 7.2-km dispersion compensation fiber and a 10-km single-mode fiber) under a strong Raman pumping condition. Under the strong Raman pumping condition, more Stokes lines are generated due to the enhanced RS-induced oscillations of Brillouin Stokes lines at short wavelength band, thus suppressing self-lasing cavity mode oscillations at long wavelength band. In the experiments, the multi-wavelength Brillouin comb with an ultra-wide bandwidth of 63.5 nm (1513 nm–1576.5 nm) with frequency spacing of double Brillouin frequency shift, which is the largest bandwidth from Brillouin fiber lasers, to the best of our knowledge, has been achieved. The proposed ultra-wide bandwidth Brillouin-Raman fiber laser has potential applications in optical communication, optical wavelength division multiplexing, and fiber sensing.