Rb^(87)原子钟锁频精度的优化

The Optimization of Accuracy to Lock the Frequency about Rb^(87) Atomic Clocks

在原子钟系统研究中,激光频率的微小变化会导致CPT共振信号幅值的大幅度减小。根据饱和吸收稳频原理,设计了一种比例积分锁频电路,通过对激光器频率调制后的解调曲线进行判断,在FPGA中进行处理并通过PI控制模块及时反馈回激光器中。实验结果表明,运用此电路后闭环锁定100 ms内激光频率的相对起伏为390kHz,频率稳定度为1.307 09×10^(-10),满足当前原子钟稳定性的要求。

In the study of atomic clock system,small changes of laser frequency can lead the amplitude of CPT resonance signal to decrease significantly.On the principle of saturated absorption frequency stabilization,we designed a proportional integral locking frequency circuit,by making ajudgment to the demodulation curve after laser frequency modulation,processing in the FPGA and feeding back the error signal to the laser by PI control module timely.Experiment result showed that,the relative fluctuation of laser frequency is 390 kHz with in 100 ms after closed-loop locking using this circuit,frequency stability reached 1.307 09×10^-10,will meet the requirements of the stability of CPT atomic clocks.