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High Spatial-Resolution and Sensitivity Interferometric OTDR

Many kinds of silica-based glass waveguide circuits1 and LiNbO3 waveguides devices2 have been proposed. These devices are highly potential for optical communication systems and optical sensor systems. To develop these waveguide devices, a diagnosing system for detecting fault locations and characterizing them is necessary. The interferometric optical-time-domain reflectometer (OTDR) is promising to apply to diagnosing the optical devices, because of high spatial- resolution and high sensitivity compared with conventional OTDR systems. The interferometric OTDR was based on the Michelson interferometer using a low-coherent light source3. The reflectance profile inside the optical components is described by the distribution of the interferometric signal power between the reflection light from the scattering centers and the reference light.