Inter-satellite coherent optical communication system based on composite axis phase-locking

Abstract

An inter-satellite coherent optical communication system based on composite axis phase-locking can be applied to an inter-satellite optical communication system with a wide range of signal optical frequencies and high-speed changes. Using the combination of laser temperature tuning and external tuning, the real-time tracking of the optical phase of the local oscillator to the optical phase of the received signal is realized. At the receiving end, the field programmable gate array (FPGA) is used as the digital signal processor to realize the extraction of the phase error signal and the frequency difference signal between the signal light and the local oscillator light. The optical temperature tuning port of the local oscillator is driven according to the signal light and the frequency difference signal of the local oscillator to realize frequency unloading. The feature of the invention is to combine the wide range and low bandwidth of temperature tuning with the narrow range and high bandwidth of external tuning. In the initial stage of phase-locking, temperature scanning is used to quickly enter the loop. After phase-locking, the frequency is unloaded in real time through temperature tuning to ensure that the system can maintain stable operation of the loop in the wide-range frequency drift caused by the Doppler effect. The invention can realize inter-satellite high-sensitivity homodyne coherent optical communication.

Description

Inter-satellite coherent optical communication system based on composite axis phase-locking technical field The invention belongs to the satellite optical communication field of homodyne coherent detection, and this system device will The low bandwidth is combined with the narrow range, high bandwidth characteristics of external tuning. Real-time compensation for inter-satellite Doppler effect can be achieved, The stable operation of the optical phase-locked loop is realized. The phase error signal is extracted by undersampling, which reduces the need for back-end electronics. device bandwidth requirements. Background technique [0002] With the improvement of the communication rate requirements of communication satellites, the traditional intensity modulation direct detection communication system can no longer be used. fulfil requirements. The coherent optical communication system can meet the requirements of communication satellites for communication speed and com...

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Problems solved by technology

This dual frequency-locked loop increases the complexity of the system

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