基于 45°倾斜光纤光栅的光纤激光频率梳

A highly reliable and stable erbium^-doped mode^-locked fiber laser was constructed using a 45° ^-tilted fiber grating (45°-TFG) as a fiber polarizer. Based on this, precise signal stabilization of the repetition frequency f_rep and carrierenvelope offset frequency f_ceo was achieved. When the pump power is 228 mW, the mode^-locked laser oscillator based on a 45°^-TFG can achieve an ultra^-short pulse output of 3 dB with a spectral bandwidth of 60. 4 nm and a pulse width of 68 fs. The root mean square stability of the power reaches 0. 033% within 12 hours, and it can maintain a good stretched modelocked state over a large pump range. After self^-built chirped pulse amplification, super^-continuum spectrum generation, and f- 2f self^-reference beat interference optical path, f_ceo signal with a signal-to^-noise ratio of 32 dB was obtained. Finally, by building an active feedback control circuit based on a phase^-locked loop, the f_rep and f_ceo signals were traced back to a GPS time^-frequency system, and the frequency instability of the f_rep and f_ceo signals was measured to be 2. 38×10⁻¹² and 6. 41×10⁻¹⁶ within an average time of 1 second. This is the first implementation of a fiber laser frequency comb based on a 45°^-TFG, indicating the potential of a 45°^-TFG based mode^-locked fiber laser in practical applications.