Compact 980-nm All-Polarization-Maintaining Dispersion-Managed Figure-9 Yb-Doped Fiber Laser

The 980-nm ultrafast laser with an all-polarization-maintaining (all-PM) fiber structure has the advantages in terms of robustness and compactness, rendering it an appealing and promising light source for applications such as underwater resource exploration and high-speed communication. In this study, we report a compact and stable all-PM dispersion-managed figure-9 Yb-doped fiber laser operating at 980 nm, designed to overcome the inherent challenges of three-level systems in this wavelength regime. The incorporation of a 980-nm chirped fiber Bragg grating serves multiple roles as a dispersion compensator, output coupler, and filter, enable robust mode-locking operation from 50.1 to 71.1 MHz repetition rate. By optimizing the net cavity dispersion near zero, a compressed pulse duration of 187 fs with a 3-dB bandwidth of 8.2 nm was obtained at 59.6 MHz repetition rate. Moreover, this all-PM fiber configuration and dispersion management strategy can effectively suppress noise and achieve exceptional long-term stability. This study provides a robust, cost-effective, and alignment-free solution for the generation of high-reliability femtosecond pulses in the 980 nm region.