Highly stable optical frequency atomic clock based on dual-frequency Faraday semiconductor laser

Abstract

The invention provides a high-stable optical-frequency atomic clock based on a dual-frequency Faraday semiconductor laser. The high-stable optical-frequency atomic clock includes a dual-frequency Faraday semiconductor laser, a half-wave plate, a third polarization beam splitter prism (10), a modulation transfer spectrum frequency stabilization module (11), a servo Feedback circuit (12), high-frequency detector (13), spectrum analyzer (14) and frequency counter (15), the dual-frequency Faraday semiconductor laser includes laser diode (1), collimating lens (2), Faraday atom filter and the laser cavity mirror (7), one of the output laser beams enters the modulation transfer spectrum frequency stabilization module, and the other beam enters the dual-wavelength laser beat signal spectrum and counts respectively. By adjusting the temperature and magnetic field conditions, the transmission spectrum of the present invention can obtain two stable transmission peaks with similar transmittance, and realize the stable output of the dual-wavelength laser. The atomic clock of the present invention can get rid of the optical comb, and the second stability is better than 10 ‑14 .

Description

【Technical field】 [0001] The invention belongs to the technical field of atomic clocks, and in particular relates to a high-stable optical-frequency atomic clock based on frequency selection of a Faraday atomic filter to realize a dual-wavelength semiconductor laser. 【Background technique】 [0002] In 1967, since the SI unit second was defined at the microwave transition frequency between the ground state energy levels of the cesium atom, since then, the microwave frequency standard of the cesium atom has received attention and continued to develop, and people have done a lot of work on the frequency standard of the cesium atom (cesium atomic clock) . Cesium atomic microwave frequency standard is composed of light, microwave resonance physical unit and circuit unit. The microwave frequency generation and control circuit controls the microwave source through the signal of the photodetector; the microwave clock needs a microwave source and an optical system, and the stability...

AI Technical Summary

Problems solved by technology

Since the Faraday filter only allows the two frequency laser longitudinal modes whose frequency interval is the working atomic transition wavelength to pass, the whole system can work, and the Doppler absorption peak of the CPT atomic gas cell is required to be more than that of the Faraday filter. The Puller transmission peaks have the same size and opposite directions, so the working conditions are very harsh and it is difficult to achieve

Moreover, the frequency stability of the output laser of the laser atomic clock based on coherent population number trapped mode locking is poor, so the frequency stability of this laser atomic clock is also poor, and the frequency stability that can be achieved by the existing technology is about 10-7 times square

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