中文摘要：

不同用户接入终端的出现使得光接入系统中上行链路的通信带宽需求急剧增加,低传输成本、高频带利用率的上行多进制光信号接入成为必然选择。设计了一种上行八进制相移键控信号并进行零差相干探测的新方案。该方案中,在光网络单元中级联3个相位电光调制器实现了高频带利用率八进制相移键控光信号的产生,在光线路终端中采用下行光信号载波作为混频源结合数字信号处理模块,实现了上行光信号的零差相干探测,相比较只采用相干探测技术的方案其接收机灵敏度值的提高超过了2 d B。

英文摘要：

Since the emergence of different user access terminals, the communication bandwidth requirement of uplink is increasing in optical access systems, and the uplink optical signal access scheme with low transmission cost and high frequency band utilization rate has become the inevitable choice. A novel scheme of transmitting 8 phase-shift keying （8PSK） signals in upstream link and using homodyne coherent detection optical access is designed and its research is carried out. In this scheme, high frequency band utilization rate 8PSK optical signals is generated through using cascaded three phase modulators at the optical network unit （ONU）, and at the optical line terminal （OLT） the optical carder of downstream signals is used as mixing source and DSP module is also be adopted to achieve homodyne coherent detection of upstream signals for enhancing the receiver sensitivity than 2 dB, compared with only using coherent detection.