CPT atomic frequency standard laser frequency modulation index locking device and method

Abstract

The invention discloses a CPT atomic frequency standard laser frequency modulation index locking device and method. The power of a microwave signal superposed on VCSEL drive current is modulated; simultaneously, synchronous phase-discrimination of a light inspection signal is carried out, so that a signal that the extreme value of a Doppler absorption line is changed with the modulation index of a frequency modulation laser is obtained; furthermore, the signal is converted into a negative feedback correction signal; and the microwave power is controlled by utilization of obtained negative feedback of the correction signal, so that the modulation index of the frequency modulation laser is stabilized. The device is simple in structure; a laser frequency modulation index locking function can be realized by increasing a few components in the existing CPT atomic frequency standard device; the CPT spectral line signal obtained by the device is the strongest after locking; furthermore, change of the CPT atomic frequency standard performance due to the factors, such as random temperature change and aging of a microwave device, can be reduced; the CPT atomic frequency standard performance can be improved; and the CPT atomic frequency standard laser frequency modulation index locking device and method disclosed by the invention are suitable for small CPT atomic frequency standards.

Description

technical field [0001] The invention belongs to the technical field of atomic frequency standards, and in particular relates to a passive coherent population trapping (CPT, Coherent Population Trapping) atomic frequency standard modulation index locking device and method, through which the performance of the CPT atomic frequency standard can be improved. Background technique [0002] CPT atomic frequency standard is a small size, low power consumption, fast start-up device that provides high stability and high accuracy frequency signals, which can meet the needs of many applications such as navigation, communication, precise positioning, precision timing and precision measurement. [0003] The coherent two-color laser interacts with the alkali metal atoms to couple the two hyperfine energy levels of the ground state of the atom to the common excited state energy level. When the optical frequency difference of the coherent two-color light is strictly equal to the split between...

AI Technical Summary

Problems solved by technology

Factors such as fluctuations in ambient temperature and VCSEL aging will cause changes in laser current, resulting in changes in modulation depth; factors such as temperature fluctuations and aging of microwave devices will cause changes in microwave power, which will also cause changes in modulation depth, resulting in VCSEL output. The change of optical power distribution of coherent polychromatic light in each frequency component, thus causing the performance change of CPT atomic frequency standard

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