A Doppler frequency shift compensation system and compensation method in coherent optical communication

Abstract

The invention applies to the field of coherent light communication and provides a Doppler frequency shift compensation system and compensation method in the coherent light communication. The Doppler frequency shift compensation system comprises a tunable laser, a coherent light receiving system, multiway baseband filters, multiway analog-to-digital converters (ADCs) and a digital signal processor(DSP). Local oscillation light is generated by the tunable laser. The coherent light receiving system mixes signal light and the local oscillation light, converts the light into multiway electric signals and outputs the multiway electric signals. The multiway electric signals are input into the multiway baseband filters for filtering and then enter the multiway ADCs for sampling. The sampled electric signals are demodulated in the DSP. After frequency deviation between the signal light and the local oscillation light is calculated, a wavelength of the local oscillation light is fed back and adjusted, so the wavelength is kept consistent with that of the signal light. Through application of the embodiment of the invention, a frequency of the local oscillation light can be accurately adjusted and the frequency shift of the signal light resulting from the Doppler effect can be rapidly compensated, thereby maintaining the stable working of the system.

Description

technical field [0001] The invention belongs to the field of optical communication, and in particular relates to a Doppler frequency shift compensation system and compensation method in coherent optical communication. Background technique [0002] The coherent optical communication system has the advantages of high sensitivity, long relay distance, good selectivity, and large communication capacity. In the application scenarios of satellite ground communication and inter-satellite communication, it has great development potential. [0003] However, according to the principle of coherent optical communication, it is necessary to mix the laser light (local oscillator light) generated by local oscillation with the input signal light in the optical mixer to obtain the same frequency, phase and amplitude as the signal light. Regularly changing intermediate frequency signals. Then the intermediate frequency signal is processed. In practical applications, the frequency differenc...

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Problems solved by technology

[0005] The purpose of the embodiments of the present invention is to provide a Doppler frequency shift compensation system and compensation method in coherent optical communication, so as to solve the problem that the signal light produces a large frequency deviation under the action of the Doppler effect, which affects the normal operation of the coherent optical communication system The problem

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