High-performance Pc-otdr Technology Research

This paper presents a approach to design a 1 .55um single-mode fiber optical time-domain reflectometer with pc-bus interface (PC-OTDR). The approach uses a pulsed semiconductor lasers, a low-noise and low-temperature receiver with a PIN diode detector and FET transimpedance amplifier together, and means of digital-averaging and digital-filtering signal processing, to reduce the receiver's noise to a minimum. It uses a Y type fiber distributor to reduce the reflection form the front of tested fiber too. By enhancing the receiver s sensitivity and signal-noise ratio we can enlarge the dynamic range of PC-OTDR greatly. The width of pulse can be selected by programming to ensure the spatial resolution for all kinds of application. Changed the traditional structure, the PC-OTDR obtain more stronger ability of exchanging data with computer. So it can use soft to process signal to improve the dynamic range of PC-OTDR again. We obtain a virtual-instrument system and present the idea on testing parameter optimized. The PC-OTDR fit the application of in-service monitoring system for optical fiber communication networks. It structure another testing system easy.By means of receiver, AID converter, pc-bus interface, system soft designed and made, we structure experiment system. A PC-OTDR with dynamic range of 38dB, 10-rn spatial resolution is demonstrated by experiment results. The system with pc-bus structure can be integrated in one card. Using soft developed under VC++6.O, a virtual instrument system can be obtained.