Power Asymmetric Ring Configuration for Tunable Fiber Laser With Reduced Path

Single longitudinal mode (SLM) fiber lasers are of significant research and practical value due to their unique performance and broad application potential in modern science, technology and industry. A SLM erbium-doped fiber laser (EDFL) with a power asymmetric ring configuration is proposed and experimentally validated. Compared with other saturable absorber structures, the proposed scheme with few fiber mode significantly reduces the optical path inside the cavity, requiring only one transmission through the main laser cavity. It is demonstrated to exhibit a remarkably narrow linewidth and an exceptional optical signal-to-noise ratio (OSNR). Experimental investigations reveal that a coefficient of 0.4 yields enhanced stability, with the maximum variations in the central wavelength confined to 0.008 nm. The wavelength of the proposed SLM EDFL exhibits a tuning range of 1552.460 nm to 1552.620 nm. The EDFL with a high OSNR of 68.78 dB and an narrow linewidth of 840 Hz is achieved at a pump power of 100 mW. This study presents a groundbreaking new approach to the design and performance of such lasers.