In this paper, a demonstration of performance of a multi-wavelength Brillouin Erbium Fiber Laser (BEFL) with double Brillouin spacing (DBS) output comb and Q-switching characteristics featuring a figure-of-eight configuration is presented. It utilizes a four-port circulator to discriminate the odd and even order Stokes lines which allows, using 7 km long dispersion shifted fiber (DSF), the generation of a spectrum with DBS, multi-wavelength comb of nine lasing lines and a 0.16 nm spacing. The Q-switched pulse trains are obtained from the proposed BEFL configured with the DSF and pumped at 1480 nm and power ranging from 20 mW to 40 mW based on relaxation oscillation technique. It has the highest repetition rate of 609 kHz and the smallest pulse width of 0.73 μs at the pump power of 40 mW. The highest pulse energy of 6.15 nJ is obtained at pump power of 30 mW. The repetition rate and pulse width of the BEFL are reduced by replacing the DSF with 10 km long nonzero dispersion shifted fiber (NZ-DSF).
Investigation of Q-Switching Characteristics in Single- and Double-Spacing Multi-Wavelength Brillouin Erbium Fiber Laser