频率调制光谱稳频法的信号处理算法研究

Research on Signal Processing Algorithm of the Laser Frequency Stabilization Based on Frequency Modulation Spectroscopy

频率调制光谱稳频法利用参考气体对激光吸收量来反馈控制激光波长稳定,反馈信号的提取通过调节参考信号与吸收分量同相的方式实现。为免除移相的麻烦,提出利用吸收分量和色散分量的合成信号作为反馈信号,通过仿真证明可以利用合成信号作为反馈信号。该合成信号的提取利用两正交参考信号与合成信号耦合的方式实现,该方式方便了信号的提取,免除了调相的麻烦。最后还提出一种判定激光波长偏移的方法。

Laser frequency stabilization method based on frequency modulation spectroscopy has been applied in space spectrum instrument as this method is simple and the frequency stability is very high.The amplitude of the absorption signal is used as the feedback signal.And the amplitude of the signal is usually acquired by a reference signal with the same frequency and phase.As the phase between the absorption signal and the reference signal is unknown,phase shifter is used in this method.In order to remove the phase shifter,it uses the mixed signal of absorption and dispersion as the feedback signal.The amplitude and the phase of the mixed signal can tell us the real wavelength of the laser.Two orthogonal reference signals are used to acquire the mixed signal,so the phase shifter is removed in this method.At last a method which is used to judge the position of the wavelength is also put forward.