为了提高相干接收的超高密度波分复用无源光网络(UDWDM-PON)上行链路的谱效率,提出了一种差分二进制相移键控与幅移键控联合调制技术(DBPSK/ASK)。DBPSK/ASK-2联合调制技术通过引入相位信息使得传统ASK-2信号的谱效率由1 bit/s/Hz增加到2 bit/s/Hz。通过采用低成本的硅基马赫-曾德尔调制器和分布反馈激光器,基于DBPSK/ASK-2调制的2.5 G波特率上行链路在标准单模光纤传输80 km后的接收灵敏度为-46 dBm,相比四阶脉冲幅度调制(PAM-4)有6 dB的性能提升。

A hybrid DBPSK and ASK modulation (DBPSK/ASK) is proposed to improve the up-link spectrum efficiency in UDWDM-PON. By employing the phase information, DBPSK/ASK-2 improves the 1 bit/s/Hz spectrum efficiency of ASK-2 to 2 bit/s/Hz. With the low-cost silicon Mach-Zehnder modulator and distributed feed back laser, the 2.5 Gband up-link signal based on DBPSK/ASK-2 modulation achieves -46 dBm receiver sensitivity after 80 km standard single mode fiber transmission, which has 6 dB improvement compared to PAM-4.