Multi-wavelength Brillouin Raman random fiber laser with double Brillouin frequency shift

Abstract

In this paper, a linear full-open-cavity Raman random fiber laser generating multi-wavelength Brillouin lines with double Brillouin frequency shift is proposed. The odd-order and even-order Stokes lights are respectively output from different end. Our contrastive experiments with forward and backward Brillouin pumping schemes reveal that the signal-to-noise ratio (SNR) of the laser output by backward pump is 24.5 dB, and the SNR of the laser output by forward pump is 19.5 dB under same Raman pump power of 831.8 mW. The SNR of backward-pumped laser output is higher and the wavelength number is more than that of forward-pumped case. But the Raman pump threshold for Brillouin Stokes light generation is higher for backward-pumped laser, which results in no stable Brillouin light generation at low Raman pump power. It is believed that the results not only can provide different ideas for the further optimization of random fiber laser structure, but also can help to further expand the application range of multi-wavelength Brillouin Raman lasers in optical communication systems and optical sensing fields.