Simplified optical correlation-domain reflectometry employing proximal reflection point

We develop a new configuration of simplified optical correlation-domain reflectometry using a proximal reflection point. The experimental setup is basically composed of standard silica fibers and includes neither an optical frequency shifter such as an acousto-optic modulator nor an explicit reference path. The light reflected at the proximal reflection point, which is artificially fabricated near an optical circulator, is used as the reference light. Unlike the conventional silica-based setup, this configuration can perform a distributed reflectivity measurement along the distal half of the sensing fiber. After demonstration of the basic operation, the incident optical power dependence of the reflectivity distribution is investigated, and the existence of the optimal incident power is clarified.