Characteristics of the single-wavelength ring cavity Brillouin fiber laser operated in L-band region

We experimentally demonstrated the characteristics of a single-wavelength Brillouin fiber laser that operated in the L-band region. The 4 km of a single mode fiber plays a significant role as a nonlinear gain medium to generate stimulated Brillouin scattering effect and causes the frequency shift with ∼ 0.08 nm spacing. At a pump power of 350 mW, a Brillouin pump wavelength of 1580 nm and 50% of output coupling ratio, the Brillouin threshold power at 6.3 mW is obtained. The highest average Brillouin Stokes power of 4.07 mW has been produced at 10 mW of Brillouin pump power at 50% of output coupling ratio. The tuning range of 30 nm is recorded without any unwanted oscillating modes appeared from 1570 nm to 1600 nm. The 70% of the output coupling ratio is found to produce flattened output for BS power and signal to noise ratio. The highest value for optical signal to noise ratio is recorded at 41.36 dB, with 50% of output coupling ratio and at 1600 nm of Brillouin pump wavelength.