In-service cable-monitoring technique for hybrid fiber/coaxial networks based on frequency domain analysis incorporated with optical time-domain reflectometer and fiber benders

An integrated on-line cable-monitoring technique for hybrid fiber/coaxial ( HFC) networks is proposed and experimentally demonstrated. The in-service m onitoring of fiber optic cable and coaxial cable is achieved simultaneously by an optical time-domain reflectometer (OTDR) and the frequency domain an alysis (FDA) method, respectively, where the FDA results are encoded in the additional dummy fiber through digitally modulated fiber benders. This tec hnique can be easily developed into an automated in-service surveillance sy stem to provide real-time monitoring to enhance HFC network reliability. (C ) 2000 society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)0 1002-3].