用于短距离光通信系统中的先进调制格式研究

摘要

High-order external modulation and coherent detection technology are generally used in long-haul optical communica-tion systems to improve the overall system transmission capacity.However,a low-cost direct modulation-direct detection tech-nology tends to be more used in short-haul optical communication systems.In this case,it is necessary to adopt advanced multi-level modulation to realize high-rate large-capacity transmission.Currently,there are three principal modulation schemes considered internationally,i.e.Pulse Amplitude Modulation (PAM),Direct Detection-Orthogonal Frequency Division Multi-plexing (DD-OFDM)modulation,Carrierless Amplitude/Phase (CAP)modulation.This paper analyzes and compares their principles and performances,hoping to use them as the basis for the design of future short-haul large-capacity optical communi-cation systems.%在长距离光通信系统中，采用高阶外调制和相干接收技术来提高系统总的传输容量。但是在短距离光通信系统中更倾向于使用低成本的直接调制-直接检测技术，此时，要实现高速、大容量传输就必须采用多电平调制。目前国际上主流的调制方案有三种：PAM(脉冲幅度调制)、DD-OFDM(直接检测-正交频分复用)调制和 CAP(无载波幅度相位)调制，文章对这三种方案的原理与性能进行了分析与比较，希望以此作为未来短距离大容量光通信系统设计的依据。