日本电报电话公司(NTT)在原有的F-400光纤系统的基础上设计出传输波长为1.5μm的新型通信系统,原系统传输波长为1.3μm,它是纵贯日本本土的远距离电话通信系统的主干线。该公司为了增加陆上系统的中继距离,并避免水下系统使用中继器,正在努力开发更长波长的光纤系统。新系统采用的是1.5μm分布反馈型激光二极管,常规1.3μm零色散单模光纤和铟镓砷雪崩光电二极管。该系统在陆上的无中继传输距离为80公里,用于海底通信时无中继传输距离达120公里。这就可以在陆上 Based on the original F-400 optical fiber system, NTT designed a new communication system with a transmission wavelength of 1.5μm. The transmission wavelength of the original system is 1.3μm. It is a long-distance telephone communication system running through Japan The main line. The company is working hard to develop longer wavelength optical fiber systems to increase the repeater distance over terrestrial systems and to avoid the use of repeaters in submarine systems. The new system uses a 1.5μm distributed feedback laser diode, a conventional 1.3μm zero-dispersion single-mode fiber and an indium gallium arsenide avalanche photodiode. The system has a repeater transmission distance of 80 km on land and a repeater transmission distance of 120 km for submarine communications. This can be land