Application of modulation and demodulation of photo-electric signal in laser frequency stabilization

Laser frequency standard is high precision laser signal whose frequency is locked on the transition frequency between hyper fine energy levels of atom or molecule. Frequency modulation spectroscopy is often adopted to control the laser frequency. At the present time, the saturated absorption FM is a fashionable method of laser frequency stabilization since the molecule saturated absorption spectrum line-shape is narrower with more accuracy reference frequency. According to the physics principle, by using the technology of signal processing, spectra line-shape of FM was obtained in theory. Its properties were analyzed and optimum parameter effecting on resolution of demodulation signal was discussed. Good experiment result was obtained under the guide of theory.