Wavelength-precisely tunable erbium-doped fiber laser based an all-fiber Michelson interferometer

Abstract A tunable erbium-doped fiber laser (EDFL) based on a Michelson interferometer (MI) configuration and dual parallel fiber Bragg gratings (FBGs) is proposed and experimentally validated. The system integrates the MI with a broadband FBG inscribed using femtosecond laser technology. Precise wavelength tuning is achieved through strain-induced shifts in the Bragg wavelength, enabling constructive interference and wavelength selection within the laser cavity. The experimental results demonstrate a tuning range from 1561.39 to 1561.95 nm, with a narrow wavelength spacing of 0.04 nm. The laser exhibits high stability, with wavelength fluctuations limited to 0.012 nm and power variations within 0.55 dB over a 50 min evaluation period. The proposed structure not only simplifies the system, but also maintains excellent performance, representing a significant advancement in tunable fiber laser technology with enhanced tuning accuracy, stability, and compactness. This design offers flexibility for applications in optical sensing, communication, and spectroscopy.