在国家自然科学基金网(NSFCNet)上已实现由400 km×10 Gbit/s传输链路直接升级的一路400 km×40 Gbit/s光传输实验的基础上,采用自行研制的40×40 Gbit/s载波抑制归零(CS-RZ) 码多波长光发送源,进行了160 km的1.6 Tbit/s(40×40 Gbit/s)波分复用(WDM)光传输实验。实验结果表明,对于常规中短距离10 Gbit/s传输链路可以直接升级至40 Gbit/s。但是由于40 Gbit/s传输系统的色散容限小于60 ps/nm,而且传输光纤与色散补偿模块的色散斜率不匹配,要实现40通道40 Gbit/s的传输,必须对40个信道分别进行精细的色散补偿。这也说明,对于宽带的40 Gbit/s多波长系统,有必要优化设计或更新传输链路。

A 40×40 Gbit/s multi-wavelength carrier-suppressed return-to-zero (CS-RZ) format optical transmitter is designed. Based on this transmitter and the experiment of one channel 400 km×40 Gbit/s optical transmission which was upgraded from the National Natural Science Foundation of China Net (NSFCNet, 400 km×10 Gbit/s), a 40×40 Gbit/s wavelength division multiplexing (WDM) optical transmission is also realized. The results show that it is feasible to upgrade a middle and short haul 10 Gbit/s WDM optical transmission system to 40 Gbit/s. However, the chromatic dispersion must be compensated precisely in every channel, since the dispersion tolerance of 40 Gbit/s system is lower than 60 ps/nm and the dispersion slope of the transmission optical fiber does not match well the dispersion slope of the dispersion compensation module. The results also show that the system optimization or the links renewal is necessary for 40 Gbit/s WDM system.