OTDR in a 147 km single-mode fibre in 1.55 μm wavelength region using an LD and GaInAs/InP APD at room temperature
A Rayleigh backscattered signal over 147.7 km of single-mode optical fibre has been observed for the first time by long-range, optical time-domain reflectometry (OTDR) usinga 1.54 μm high-power semiconductor laser (LD) and a GaInAs/InP APD with a small dark current at room temperature. A one-way backscattered dynamic range of 29.3 dB at room temperature has been achieved.