A multiservice fiber-optic subscriber system using wavelength division multiplexing technology has been developed by Nippon Telegraph and Telephone Corporation to provide both 64 kbits/s and broad-band communication services on a single multimode fiber. The subscriber network is formed in a star topology to facilitate bidirectional connection. The system was put in service in March, 1985, as part of the information network system (INS) model system. This paper describes the configuration and characteristics of the video distribution system of this fiber-optic subscriber system. The distribution system uses analog baseband video transmission at a 0.89μm wavelength. The video channel selection is made by an FDM video tuner installed in a central office. The overall performance successfully met design objectives.

800 Mbit/s digital transmission systems, using nonredundant three-level and four-level codes, have been studied as a means of providing an economically attractive digital transmission system. These systems have been designed to be compatible with a 60 MHz analog system in repeater spacing and repeater size, so as to be easily introduced into the existing network. These systems with 11 520 telephone channels, exceed the 60 MHz analog system in both capacity and economy. Due to repeater construction factors, it became clear that the three-level code is more suitable. This paper describes the design and performance of 800 Mbit/s digital transmission systems and repeaters.