Wavelength tunable single-frequency ring cavity fiber laser utilizing external injection locking signal

Abstract The ring cavity fiber laser with saturable absorption fibers is a simple and practical technical way of achieving single-frequency laser output. However, this structure cannot obtain wavelength-tunable laser output. In this work, an external injection locking signal launched by tunable LD is used to optimize the tunability in single-frequency ring cavity fiber lasers. By aligning the external injection signal, tunable laser output ranging from 1544.13 to 1546.51 nm is achieved. The maximum output is 16.5 mW and the linewidth is less than 6.15 kHz. The operation process and the linewidth compression effect of external Injection signals are investigated. The results indicate that there is a correlation between the output signal-to-noise ratio and the output linewidth, and this wavelength-tuning structure has the potential for rapid tuning. This work provides a technical solution for achieving a tunable single-frequency laser in the ring cavity structure.