在级联相位调制的100 Gbit/s光信号传输系统中,提出了占空比为33%的光交错相移键控归零码(RZ-SDPSK)和占空比为67%的光交错相移键控载波抑制归零码(CSRZ-SDPSK)的产生和检测方案。通过50 km的普通单模光纤(SMF)和8 km的色散补偿光纤(DCF)传输后,当入纤功率相同时,CSRZ-SDPSK码具有较高的色散容限;如果仅考虑一阶偏振模色散(PMD),RZ-SDPSK信号具有较好的抗PMD特性。入纤功率在0~10dBm范围内调节时,两种码型码有相似的传输特性。通过125 GHz带宽的三阶高斯滤波器后,RZ-SDPSK码接收性能较优,并且三阶高斯带通滤波器(DBPF)的带宽值必须大于100 GHz,才能有效地恢复信号时钟。
We propose and demonstrate the generation and detection of two new return-to-zero staggered differential phase-shift keying(RZ-SDPSK) modulation formats with 33% duty cycle and 67% duty cycle for 100 Gbit/s transmission.The their transmission characteristics shows that the generated RZ-SDPSK signal with 33% duty cycle is especially suited for single carrier transmission in the metropolitan area network without first-order-PMD compensation and with a lower bandwidth OBPF,and the CSRZ-SDPSK with 67% duty cycle signal has higher dispersion and nonlinear tolerance.To extract clock signals effectively,the bandwidth of OBPF should be larger than 100 GHz.