We propose a stable and high optical signal-to-noise ratio(OSNR)compound linear-cavity single-longitudinal-mode(SLM)erbium-doped silica fiber laser.It consists of three uniform fiber Bragg gratings(FBGs)and two fiber couplers to form a simple asymmetric four-cavity structure to select the longitudinal mode.The stable SLM operation at the wavelength of 1544.053 nm with a 3 dB bandwidth of 0.014 nm and an OSNR of~60 dB was verified experimentally.Under laboratory conditions,a power fluctuation performance of less than 0.05 dB for 5 h and wavelength variation of less than 0.01 nm for about 150 min is demonstrated.Finally,the characteristic of laser output power as a function of pump power is investigated.The proposed system provides a simple and cost-effective approach to realize a stable SLM fiber laser.
