Exceeding 670-mW Linearly Polarized Single-Frequency Fiber Laser Using a 0.6-cm Polarization- Maintaining Yb-Doped Crystal-Derived Silica Fiber

Abstract

A polarization-maintaining Yb-doped crystal-derived silica fiber (PM-YCDSF) was fabricated, exhibiting a gain coefficient exceeding 5.5 dB/cm at 1030 nm, a birefringence of 6.31×10−5, and a polarization extinction ratio (PER) variation of only 2.1 dB during the temperature range of 20–200 °C. Using only 0.6 cm of active fiber, a short-cavity distributed Bragg reflector (DBR) single-frequency fiber laser (SFFL) was constructed. The laser achieved a slope efficiency of 65% and a PER of 31.5 dB. Its output power is up to 672 mW. To the best of our knowledge, this is the first DBR SFFL exceeding 670-mW linearly polarized output with only 0.6-cm active fiber. Furthermore, the laser exhibited a threshold power as low as 3 mW and an optical signal-to-noise ratio exceeding 80 dB. The power fluctuation in the mode-hop- free operation was below 0.17% (RMS) over 570 min, and the relative intensity noise stabilized at approximately −159.8 dBc/Hz above 8.8 MHz. Additionally, by employing a homemade all-fiber quarter-wave plate, a circularly polarized light with an ellipticity angle of approximately 43.58° could be maintained during the 120 min. And its output power also reached 583 mW. These results show that the PM-YCDSF is a promising gain medium for the compact and high-power-density SFFL sources applied in atomic physics, quantum sensing, biomedical imaging, precision measurement, and beyond.