SSB (Single Side Band)-OOFDM (Optical Orthogonal Frequency Division Multiplexing) link implementation method and system for beat interference cancellation

Abstract

The invention provides a DD (Direct Detection)-SSB (Single Side Band)-OOFDM (Optical Orthogonal Frequency Division Multiplexing) link implementation method and system for beat interference cancellation, and relates to the field of optical communication. In a DD-OOFDM system, a polarization modulator and an optical band-pass filter generate a cross-polarized SSB-OOFDM signal; the SSB-OOFDM signal is injected to a single side beat interference (SSBI) cancellation receiver (BICR) after optical fiber transmission, a polarization beam splitter (PBS) splits the cross-polarized optical carrier and OOFDM side band in the SSB-OOFDM signal into two linearly-polarized SSB-OOFDM signals, a balance photo-detector (BPD) performs photoelectric conversion, differential photocurrent output by a subtracter only contains an RF (Radio Frequency)-OFDM (Orthogonal Frequency Division Multiplexing) signal, while the SSBI component is completely canceled, so that the guard interval between the optical carrier and the OOFDM side band is greatly reduced and the spectral efficiency of the system is improved. The BICR has the advantages of simple structure, low cost and insensitivity to signal wavelength, and is significant for improving the performance of the DD-OOFDM system.

Description

technical field [0001] The present invention relates to the field of optical communication, in particular to optical polarization orthogonal single sideband (SSB) modulation technology in Direct Detection Optical Orthogonal Frequency Division Multiplexing (DD-OOFDM) system and inter-signal beat frequency interference elimination receiver based on balanced detection (BICR) structure, providing a SSB-OOFDM link implementation method and system with high system performance, low structural complexity, and low cost without inter-signal beat frequency interference (SSBI). Background technique [0002] In recent years, with the continuous improvement of global informatization, the demand of human society for information transmission capacity has grown at an alarming rate. In order to meet the requirements of the existing communication system for large bandwidth, people pay more attention to the optical network with high transmission capacity. However, with the continuous increase ...

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Problems solved by technology

For example, a beat frequency interference cancellation receiver composed of an optical carrier suppression filter, a 1×2 optical coupler and a balanced detector improves the system’s tolerance to phase noise and fiber dispersion, but half the optical power It is used to suppress SSBI, but has no contribution to the received RF-OFDM signal, which reduces the sensitivity of the receiver and the power utilization of the system; the improved beat frequency interference elimination receiver consists of an optical comb filter, an Composed of 2×2 optical couplers and a balanced detector, although the optical power of the output RF-OFDM signal is increased by half, the optical comb filter used in the receiver is sensitive to wavelength and requires a steeper filtering edge, so The receiving module cannot achieve colorless work

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