Construction method of mode-division multiplexing fiber-optic communication system and a constructed fiber-optic communication system

Abstract

The present invention relates to a construction method of a mode-division multiplexing fiber-optic communication system, which includes following contents: converting multiple-input optical signals into optical propagation modes supported by a graded-index ring-core optical fiber at a transmitting end, after being multiplexed by a mode multiplexer, injecting the optical signals into the graded-index ring-core optical fiber for transmission; using a mode de-multiplexer to separate optical signals of different mode groups at a receiving end firstly; and for the separation of internal modes of the same mode group, adopting a multi-channel reception and a digital signal processing method based on a multiple-input multiple-output equalization for processing: for the separation of modes in a base mode group and a high-order mode group, using a digital signal processing algorithm including a 2×2 multiple-input multiple-output equalization and a digital signal processing algorithm including a 4×4 multiple-input multiple-output equalization for recovery processing, respectively. The method according to the present invention only needs to add an optical receiver and a digital signal processing module based on the 4×4 multiple-input multiple-output equalization repeatedly while adding the mode group to expand communication capacity. Compared with the prior art, the present invention has the characteristics of low complexity, high scalability and easy upgrading.