Ultra-Narrow-Bandwidth Single-Frequency Self-Sweeping Ytterbium-Doped Fiber Laser

The sterling merits of single-frequency self-sweeping fiber laser in linewidth, compact design, wavelength and pulse dynamics make it a promising tool for laser measurement. In this letter, we proposed an ultra-narrow-bandwidth ytterbium-doped self-sweeping fiber laser by using a reflector including collimator and mirror. The self-sweeping state was achieved by a 2 m long fiber saturable absorber, and was confirmed by the unique pulse intensity. The central wavelength of laser located at 1065.382 nm along with a self-sweeping range within 2 pm. The radio frequency spectrum observed the relaxation oscillation and beat frequency signals. Especially, the nonlinear saturable absorption feature was confirmed by fitting the intervals of beat frequency signals. The behaviors of relaxation oscillation peaks were summarized and fitted by the empirical formula. This work provides a new self-sweeping laser tool with a narrow bandwidth and can be applied in laser ranging and tunable microwave signal generation.