Study on the Performance of Passive Digital Phase Demodulation Algorithm Based on 3×3 Coupler and the Hardware Implementation

摘要

Four kinds of passive phase demodulation algorithms based on 3×3 couplers are introduced and analyzed in this paper. The performance of these algorithms in noisy environment are theoretically investigated and simulation under five conditions including ideal situation, amplitude noise, phase noise, coupler asymmetry, and weak signal is employed. The proposed arctangent scheme utilizing three outputs is designed and implemented in hardware system based on programmable logic devices and high speed digital-to-analog converters. The performance of the proposed hardware scheme is verified experimentally by applying into the optical fiber interference system.