PXI (PCI eXtensions for Instrumentation) system-based passive CPT (Coherent Population Trapping) atomic clock experimental facility and method

Abstract

The invention discloses a PXI (PCI eXtensions for Instrumentation) system-based passive CPT (Coherent Population Trapping) atomic clock experimental facility, wherein a PXI system is respectively connected with a through circuit, a current source, a microwave source, a current to voltage circuit, a crystal oscillator and a frequency tester; the crystal oscillator is connected with a power divider; one of two output ends of the power divider is connected with the microwave source, while the other end is connected with the frequency tester; a coupling circuit is respectively connected with the PXI system, the current source and the microwave source; a physical system is respectively connected with the output end of the coupling circuit and the input end of the current to voltage circuit; the physical system is also connected with the through circuit. The invention further discloses a PXI system-based passive CPT atomic clock experimental method, wherein the PXI system is used as a control core for realizing the temperature control, direct current locking and feedback, microwave locking and feedback, and self-turning of working parameters. The experimental facility and method disclosed by the invention have the advantages of being simple in structure, high in degree of automation, and high in processing capability for digital signals, and are suitable for experiment research on various schemes of a passive CPT atomic clock.

Description

technical field [0001] The invention relates to the field of atomic clocks, in particular to a passive CPT atomic clock experimental device based on a PXI system, and also to an experimental method for a passive CPT atomic clock based on a PXI system, which is applicable to experimental research on working parameters and different physical schemes of a passive CPT atomic clock. Background technique [0002] The physical mechanism of the passive coherent population-pinned (CPT) atomic clock is that the two hyperfine energy levels of the ground state of the alkali metal atom form a three-level structure with an excited state energy level, and two beams of coherent two-color light interact with it. When two lasers When the frequency difference is exactly equal to the frequency corresponding to the difference between the two hyperfine energy levels of the ground state of the atom, the mutual interference between the quantum transitions makes the atom be in a coherent superpositio...

AI Technical Summary

Problems solved by technology

When the self-developed servo circuit system is used to study the physical system, the signal-to-noise ratio and resolution of the input VCSEL current are not high enough, the phase noise and spurs of the microwave that modulate the current are not good enough, and the sampling rate and resolution of the analog-to-digital converter are not good enough. The rate cannot be taken into account at the same time, and the signal processing capability of the microcontroller is limited, etc.

When using conventional electronic instruments for research, such as signal demodulation through lock-in amplifiers and temperature control through temperature controllers, since each instrument works independently and there is no control center, it is necessary to manually control the current source and microwave source. Control, all work links in the experiment need manual intervention, resulting in low test accuracy and inconvenient operation

In addition, when studying the characteristics of the physical system, it is necessary to know the ambient temperature of the atomic vapor bubble, the modulation depth of the microwave frequency modulation signal, and the influence of the microwave feedback frequency on the contrast and frequency shift of the EIT signal, as well as the most suitable demodulation signal phase and feedback PID Parameters, the current experimental method requires human adjustment for the optimization of parameters, and cannot monitor, store and analyze the intermediate data in real time, and the degree of automation is low

[0005] When conducting experimental research on different physical schemes of passive CPT atomic clocks, such as the research on Ramsey-CPT atomic clocks, there are high requirements for the sampling rate and resolution of data acquisition, the speed of digital signal processing, and the synchronization of timing. The self-developed servo circuit system and conventional electronic instruments are difficult to meet the requirements, and the scalability and portability are poor, so it is impossible to conduct comparative research on different physical solutions under the same conditions

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