Single-frequency kHz-linewidth 1070 nm Laser Based on Yb:YAG Derived Silica Fiber

A kHz-linewidth single-frequency laser at 1070 nm was demonstrated based on homemade heavily Yb3+-doped Yb:YAG-derived silica fiber (YDSF), which was fabricated by molten-core fabrication method. Stable single-longitudinal-mode (SLM) lasing operation was achieved by adopting ring cavity configuration, where a piece of un-pumped polarization maintaining Yb3+-doped fiber (PM-YDF) was utilized as a saturable absorber (SA). A maximum output power of the stable single longitudinal mode continuous wave laser up to 40 mW was obtained with a pump power of 542 mW at 976 nm. The optical signal-to-noise ratio (OSNR) was ~60 dB, and the laser linewidth was measured to be less than 4.3 kHz, which is limited by the measurement setup. The fluctuation of center wavelength of the laser was less than 0.1 pm within 10 min. Wavelength tuning from 1069.99 to 1070.42 nm was achieved by controlling the temperature of the fiber Bragg grating (FBG).