Wide-range fast-tuning three-stage composite shaft phase locking method and structure in homodyne coherent detection

Abstract

The invention discloses a wide-range fast-tuning three-stage composite shaft phase locking method and structure in homodyne coherent detection, belongs to the technical field of space laser communication coherent detection, and aims to solve the problems in the prior art. A temperature tracking loop is responsible for large-range frequency capture in an initial state, wherein the capture range canreach dozens of GHz, and the frequency difference between a local oscillator source and a signal source is pulled into the bandwidth of a PZT tracking loop after passing through the loop; the PZT tracking loop is started, and the frequency offset is achieved by controlling a piezoelectric ceramic column of a local oscillation source, wherein the frequency shift range of the loop is 3 GHz, the bandwidth of the loop is several KHz, the tuning speed is high, and the tuning range is smaller than that of the temperature tracking loop; the frequency difference is pulled into the bandwidth of a last-stage AOFS tracking loop; the AOFS tracking loop is started, and the speed and precision tuning of the frequency are realized by controlling the external actuator. According to the invention, the tuning range of the loop is at least dozens of megahertz, but the tuning speed reaches the maximum value, the loop bandwidth can reach the megahertz magnitude, and the control precision is higher than KHz.

Description

technical field

[0001] The invention relates to a wide-range fast-tuning three-stage compound axis phase-locking method and structure in homodyne coherent detection, and belongs to the technical field of space laser communication coherent detection. Background technique

[0002] For space laser communication technology, it is developing in the direction of high speed and long distance. Satellite, air-ground and other long-distance channels. For the above application background, the traditional direct detection method can no longer meet the demand, and the coherent detection technology has gradually aroused a research boom. For coherent detection technology, it has the characteristics of high detection sensitivity, long communication distance, large capacity, and compatibility with multiple modulation formats, so it is suitable for long-distance, fast-speed communication links. Compared with the traditional detection unit, the homodyne coherent detection unit also needs to ...

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