为了兼顾用户端光网络单元的特点和传输速率, 在接收端采用可集成化的相干检测方案替代传统的直接检测方案, 分析了电吸收调制器的偏压特性, 搭建了速率为40Gbit/s的5km双向接入网通信系统, 对以分布式反馈激光器和电吸收调制器为上行发射机的可集成光网络单元进行了传输测试。结果表明, 在直接检测方案前向纠错(FEC)下, 双向传输下行信号接收灵敏度和上行信号接收灵敏度分别达到了-18.31dBm和-17.94dBm; 在相干检测方案FEC下, 双向传输下行信号接收灵敏度和上行信号接收灵敏度分别达到了-32.51dBm和-29.76dBm。相干检测方案的上行和下行接收灵敏度相较于直接检测分别有14.20dB和11.82dB的提升。该研究为未来用户端光网络单元提供了一种高速率可大规模部署的集成化方案。

In order to take into account the characteristics of the optical network unit and the transmission rate of the user end, an integrable coherent detection scheme was used to replace the traditional direct detection scheme at the receiving end. The bias characteristics of the electro-absorption modulator (EAM) was analyzed. A 5km bidirectional access network communication system with a rate of 40Gbit/s was built, and the transmission test of the integrable optical network unit with the distributed feedback (DFB) laser and the EAM as the upstream transmitter was carried out. Under the direct detection scheme and forward error correction (FEC), the receiving sensitivity of downstream signal and upstream signal of bidirectional transmission are -18.31dBm and -17.94dBm respectively. Under the coherent detection scheme and FEC, the receiving sensitivities of downstream and upstream signals are -32.51dBm and -29.76dBm, respectively. The results show that the upstream and downstream receiving sensitivities of the coherent detection scheme are 14.20dB and 11.82dB higher than those of the direct detection scheme, respectively. The result of this work provides a high-speed and large-scale deployment integrated scheme for the optical network unit of the future client.