Highly stable frequency tunable narrow linewidth laser and its application method

Abstract

A highly stable frequency tunable narrow linewidth laser, comprising: a temperature control circuit connected in sequence, a narrow linewidth laser, a drive circuit, a first fiber coupler connected to the output end of the narrow linewidth laser; a tunable microwave A source module; a frequency shifter connected to the first fiber coupler; a second fiber coupler connected to the optical output end of the frequency shifter; an etalon connected to the second fiber coupler; first and second power detection modules respectively connected to the second optical fiber coupler and etalon; the first and second amplifying circuits are respectively connected to the output ends of the first and second power detection modules; the first and second analog-to-digital conversion circuits are respectively connected to the first and second The analog-to-digital conversion circuit is connected; a single-chip microcomputer is connected to the output terminals of the first and second analog-to-digital conversion circuits and the driving circuit. The invention can improve the frequency stability of the narrow line width laser, reduce the line width, and realize the function of continuously tunable wavelength.

Description

technical field [0001] The invention relates to the field of narrow-linewidth lasers, in particular to a narrow-linewidth laser with high frequency stability and tunable wavelength. The laser can be applied to the fields of radar and electronic countermeasures, coherent optical communication, precision interferometry and the like. Background technique [0002] Frequency-stabilized narrow-linewidth lasers are widely used in research fields such as radar and electronic countermeasures, coherent optical communications, precision interferometry, optical frequency standards, and laser gyroscopes. According to Schawlow-Tones' laser linewidth theory, the limit of laser linewidth caused by spontaneous emission is very small, but due to unstable factors such as thermal disturbance, electronic noise and mechanical vibration, the linewidth of lasers in practical applications is much larger than the theoretical line wide limit. If there is no adjustment and control, the frequency drift...

AI Technical Summary

Problems solved by technology

The external cavity tuning frequency stabilization method uses a Littrow structure to obtain a narrow linewidth single longitudinal mode through the optical feedback of the diffraction grating in the external cavity. The external cavity laser has a significant improvement in the linewidth of the general laser, but it is difficult to guarantee the long-term The stability is sensitive to mechanical changes and temperature fluctuations; the method of locking the optical frequency to the f-p cavity is mainly based on the phase modulation optical heterodyne frequency stabilization technology of the phase modulator, which has high sensitivity and signal-to-noise ratio. Moreover, it has a large adjustment range and good frequency stabilization effect, but the adjustment process is complicated and cumbersome, and the f-p cavity itself is easily affected by changes in the external environment such as temperature changes, mechanical vibrations, etc.; the optical frequency is locked to the atomic or molecular absorption line, The frequency locking sensitivity and long-term stability of the laser can be greatly improved. However, because the absorption lines are isolated, the commonly used methods such as the saturated absorption method simply lock the optical frequency to the absorption peak, and do not have continuous wavelength tunability.

Images