Fiber-optic point-to-multipoint interface configuration for broad-band ISDN

The physical layer characteristics and hardware implementation of broadband ISDN user-network interfaces are discussed. Optical fiber cable is employed as the transmission medium due to its broad bandwidth and low loss characteristics. For terminal connections in customer premises, a point-to-multipoint wiring configuration is adopted. The techniques needed to develop the fiber-optic point-to-multipoint transmission capability to realize an effective fiber-optic point-to-multipoint interface are discussed. A frame phase alignment procedure, a burst-mode automatic optical output power circuit for a laser diode, and bit timing extraction and DC-wandering cancellation for optical bursty signals are introduced. Experimental results demonstrate the feasibility of 1-km optical interface transmission at speeds over 140 Mb/s in a point-to-multipoint wiring configuration connecting up to eight terminals