ZERO DEAD-ZONE OTDR WITH HIGH-SPATIAL-RESOLUTION FOR SHORT HAUL APPLICATIONS

The existence of dead-zones is an important drawback for optical time- domain reflectometers (OTDR), specially in short haul applications wit h a large number of optical components, In this letter, we present an OTDR system with high spatial resolution based on the time-correlated single photon counting (TC-SPC) technique. This system overcomes the d ead-zone problem by monitoring the spontaneous Stokes Raman emission ( SSRE) to avoid the intense Fresnel reflections, The high sensitivity o f the TC-SPC technique (-120 dBm) permits a high-loss budget within re asonable measurement integration times.