Tunable narrow linewidth linear cavity fiber laser based on a one-way round-trip structure

摘要

A tunable single-longitude-mode (SLM) linear cavity fiber laser based on a one-way round-trip structure with a saturable absorber (SA) is demonstrated. A one-way round-trip structure, which is combined by two circulators, is introduced to the linear cavity to suppress the backward amplified spontaneous emission noise and isolate the interference of pump light to SA. The SA is implemented by using a section of unpumped erbium-doped fiber. As the temperature increases from 10 degrees C to 45 degrees C, the laser wavelength shifts linearly form 1549.948 nm to 1550.336 nm with the recorded sensitivity of similar to 11.01 pm/degrees C. A SLM erbium-doped fiber laser (EDFL) with a high OSNR of 48 dB and an ultra-narrow linewidth of 585 Hz is obtained at the pump power of 100 mW. In accordance with the designed SLM operation, the EDFL has excellent stability in the center wavelength and the output power. The maximum fluctuations of the center wavelength and output power are 0.016 nm and 0.01 dB respectively.