A novel tunable multi-wavelength Brillouin fiber laser with switchable frequency spacing

We propose and experimentally demonstrate a novel wavelength tunable and frequency spacing switchable multi-wavelength Brillouin fiber laser by employing optical gain and absorption during the Stimulated Brillouin scattering process. The frequency spacing can be switched by only varying the Brillouin pump power. Up to 16 Stokes lines with single Brillouin frequency spacing are observed under the lower Brillouin pump power, and 7 Stokes lines with double Brillouin frequency spacing are realized under the high Brillouin pump power by exploiting the Brillouin pump absorption. The proposed multi-wavelength laser can also be tuned from 1547 to 1569 nm and has the potential applications in the areas of optical communications and sensing.