中文摘要：

光8DPSK（optical Differential 8-Phase Shift Keying）是一种多级相位调制新码型，是光通信领域研究的前沿，文章介绍了光8DPSK调制格式原理和调制解调方式，用Matlab做了仿真，绘制出了频谱图、眼图，并对占空比为0．5的RZ-8DPSK信号做了详细分析，调制和解调了64个伪随机码序列，仿真绘制了光脉冲时序图、相位差图和平衡接收后的电信号时序图。

英文摘要：

As a new multi phase modulation keying, optical Differential 8-Phase Shift Keying （8DPSK） is a subject in the most advanced research field of optical communications. This paper introduces the modulation format principle of optical 8DPSK and the way of its modulation and demodulation. With the help of Matlab, we simulate 8DPSK modulation and demodulation; draw the spectrum diagram and eye diagram and make detailed analysis of the RZ-SDPSK signals with a duty circle of 0.5, modulate and demodulate 64 PRBS signals, draw the optical pulse sequence diagram, phase-difference diagram and the electrical signal sequence diagram after balanced reception.