Linear digital phase demodulation method for high-spectral-efficiency coherent optical link

Abstract

The invention discloses a linear digital phase demodulation method for a high-spectral-efficiency coherent optical link, and relates to the technical field of optical communication, the technical field of microwaves and the field of digital signal processing. The method is as shown in figure 1 in the specification, and comprises two lasers CW1 and CW2, a polarization multiplexing Mach-Zehnder modulator PDMMZM, a 25km single-mode optical fiber SMF, two polarization controllers PC1 and PC2, an integrated coherent receiver ICR, an analog-to-digital converter ADC and a digital signal processing module DSP. Intensity modulation and phase modulation are respectively carried out on two radio frequency signals RF in an optical carrier orthogonal polarization state by using PDMMZM, the polarizationstates of a modulated optical signal and a local oscillation optical signal are manually adjusted through two PCs, the modulated optical signal and the local oscillation optical signal are sent to anICR for coherent detection, and then the signals are sent to a DSP module through ADC sampling to complete linear demodulation. According to the invention, coherent detection is combined with a digital signal processing technology to realize signal demodulation. The method has the advantages of high spectral efficiency, good linearity, high sensitivity, capability of effectively suppressing phasenoise and the like.

Description

technical field [0001] The invention relates to the technical field of optical communication, microwave technology and digital signal processing, and mainly relates to using photonics technology to realize high spectral efficiency transmission of radio frequency signals and using digital signal processing to realize linear demodulation of optical phase modulation. Background technique [0002] In the field of optical communication technology, larger transmission bandwidth, larger transmission distance, higher spectral efficiency and higher reception 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 put forward higher requirements for the performance of communication systems. The traditional optical communication system mainly adopts the method of intensity modulation / direct demodulation (IMDD), which directly modulates the intensity of the optical carr...

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

Images