异步采样全保偏光纤光梳系统研制

Development of asynchronous sampling full polarization maintaining fiber optical comb system

为了获得长期稳定的光梳光源,利用压电陶瓷(PZT)和步进电机双级反馈控制方案,研制了两台基于非线性放大环形镜(NALM)锁模的异步采样光纤光梳系统。研究表明:该系统重复频率为75 MHz,5 min内重复频率的锁定峰峰值为±2 mHz,标准差为0.70 mHz,90 h内锁定峰峰值为±10 mHz,标准差为1.26 mHz;光纤光梳输出端口的脉冲平均功率为30 mW,经3 m保偏单模光纤压缩后脉冲宽度约为90 fs;激光器的重复频率差Δf在1 Hz~500 kHz范围内连续可调,当异步采样频差Δf为80 Hz时,扫描周期为12.5 ms,可探测出信噪比为6.3的太赫兹信号。该方案避免使用传统机械延迟线,具有重复频率差精确可调、采样速度快、抗干扰能力强等优点。

In order to obtain a long-term stable optical comb light source,two asynchronous sampling fiber optical comb systems based on nonlinear amplifying loop mirror(NALM)mode locking were developed by using piezoelectric ceramics(PZT)and a stepper motor two-stage feedback control scheme.The research shows that the system has a repetition rate of 75 MHz,the locked peak-to-peak value of the repetition rate within 5 min is±2 mHz,the standard deviation is 0.70 mHz,the locked peak-to-peak value within 90 h is±10 mHz and the standard deviation is 1.26 mHz.The average power of the pulse at the comb output port is 30 mW,and the pulse width is about 90 fs after compression by 3 m polarization-maintaining single-mode fiber.The laser repetition rate differenceΔf is continuously adjustable in the range of 1 Hz to 500 kHz,when asynchronous sampling.When the frequency differenceΔf is 80 Hz,the scanning period is 12.5 ms,and a terahertz signal with a signal-to-noise ratio of 6.3 can be detected.This scheme avoids the use of traditional mechanical delay lines,and has the advantages of accurate and adjustable repetition rate difference,fast sampling speed,and strong anti-interference ability.