A simple approach for stable single polarization,single frequency,and linear cavity erbium doped fiber laser is proposed and demonstrated.A Fabry-Pérot filter,polarizer and saturable absorber are used together to ensure stable single frequency,single polarization operation.The optical signal-to-noise ratio of the laser is approximately 57 dB,and the Lorentz linewidth is 13.9 kHz.The polarization state of the laser with good stability is confirmed and the degree of polarization is>99%.
We present a stable linear-cavity single longitudinal mode (SLM) erbium-doped silica fiber laser. It consists of four fiber Bragg gratings (FBGs) directly written in a section of photosensitive erbium-doped fiber (EDF) to form an asymmetric three-cavity structure. The stable SLM operation at a wavelength of 1545.112 nm with a 3-dB bandwidth of 0.012 nm and an optical signal-to-noise ratio (OSNR) of about 60 dB is verified experimentally. Under laboratory conditions, the performance of a power fluctuation of less than 0.05 dB observed from the power meter for 6 h and a wavelength variation of less than 0.01 nm obtained from the optical spectrum analyzer (OSA) for about 1.5 h are demonstrated. The gain fiber length is no longer limited to only several centimeters for SLM operation because of the excellent mode-selecting ability of the asymmetric three-cavity structure. The proposed scheme provides a simple and cost-effective approach to realizing a stable SLM fiber laser.
