A Linear Digital Phase Demodulation Method for High Spectrum Efficiency Coherent Optical Links

Abstract

The invention discloses a linear digital phase demodulation method of a coherent optical link with high spectral efficiency. The method relates to the technical fields of optical communication, microwave technology and digital signal processing. The method is shown in Figure 1 of the accompanying drawings, including two lasers CW1 and CW2, a polarization multiplexing Mazeng modulator PDM-MZM, a 25km single-mode fiber SMF, two polarization controllers PC1 and PC2, and integrated coherent reception Machine ICR, analog-to-digital converter ADC, digital signal processing module DSP. Use PDM‑MZM to perform intensity modulation and phase modulation on the two radio frequency signals RF in the orthogonal polarization state of the optical carrier, manually adjust the polarization state of the modulated optical signal and the local oscillator optical signal through two PCs, and send them to the ICR for coherence Detection, and then sent to the DSP module through ADC sampling to complete linear demodulation. The invention adopts coherent detection combined with digital signal processing technology to realize signal demodulation, and has the advantages of high frequency spectrum efficiency, good linearity, high sensitivity, effective suppression of phase noise and the like.

Description

technical field [0001] The present invention relates to the fields of optical communication technology, microwave technology and digital signal processing, and mainly relates to the realization of high spectral efficiency transmission of radio frequency signals by photonics technology and the linear demodulation of optical phase modulation by digital signal processing. Background technique [0002] In the field of optical communication technology, greater transmission bandwidth, greater transmission distance, higher spectral efficiency and higher receiving sensitivity are always the goals pursued by researchers. The advent of the 5G era and the explosive growth of information generated by the popularization of the Internet have placed higher requirements on the performance of communication systems. The traditional optical communication system mainly adopts the method of intensity modulation / direct demodulation (IMDD), in which the intensity of the optical carrier is directly...

AI Technical Summary

Problems solved by technology

Homodyne detection requires strict matching of local oscillator light and signal light, which can obtain high sensitivity and low processing bandwidth, but requires an optical phase-locked loop, which has high requirements on device performance and is easily affected by environmental factors

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