Tunable multiwavelength Brillouin-Raman fiber laser in a linear cavity with spectrum reshaped by Rayleigh scattering

In this paper, we propose and experimentally study a simple linear cavity multiwavelength Brillouin-Raman fiber laser (MBRFL). The fiber feedback loop which consists of an optical circulator is placed at the end of the dispersion compensating fiber (DCF) to enhance the reflectivity of the Brillouin Stokes waves. As a result, 245 Brillouin Stokes lines with 0.072 nm channel-spacing are generated across the wavelength range of 18.6 nm from 1544.98 to 1563.58 nm when Brillouin pump (BP) is fixed to 1545 nm/−2.94 dBm and a single Raman pump (RP) laser power is set to 718 mW. The output spectrum is reshaped based on Rayleigh scattering by adding 45 km single mode fiber (SMF) in the cavity. The average optical signal to noise ratio (OSNR) about 18 dB has been measured in this structure. A tunable multiwavelength range of 20 nm from 1545 to 1565 nm is obtained. We also demonstrate the influence of BP wavelength and power on MBRFL.