EXTENDED-RANGE OPTICAL-TIME DOMAIN-REFLECTOMETRY SYSTEM AT 1.65 MU-M BASED ON DELAYED RAMAN AMPLIFICATION

We describe both theoretical and experimental results obtained in an i nvestigation of a new technique for increasing the dynamic range of 1. 65-mu m optical time domain-reflectometry (OTDR) systems. utilizes del ayed Raman amplification of a 1.65-mu m signal pulse by a 1.53-mu m pu mp pulse. occurs when the two pulses overlap, and this position is det ermined by the initial delay between the pulses and the fiber dispersi on. An increase in dynamic range of 17.5 dB has been observed, and the OTDR backscattered Rayleigh signal was detected up to 100 km. No sign ificant noise penalty is introduced as a result of the directionality of the Raman gain. (C) 1998 Optical Society of America.