OPTICAL TIME DOMAIN REFLECTOMETER, TEST METHOD FOR OPTICAL TRANSMISSION PATH, AND TEST SYSTEM FOR OPTICAL TRANSMISSION PATH

摘要

According to the present invention, a light source (2) outputs monitoring light (ML). A light detection part (4) detects reflected light (BL) from an optical transmission path (TL) and outputs a detection signal (VB) that indicates the intensity of the reflected light (BL). An optical multiplexer/demultiplexer (3) outputs monitoring light (ML) inputted from the light source (2) to the optical transmission path (TL) and outputs reflected light (BL) inputted from the optical transmission path (TL) to the light detection part (4). A processing part (1) detects first timing at which the detection signal (VB) becomes smaller than a first threshold value, detects second timing at which the value of the detection signal (VB) becomes smaller than a second threshold value, and calculates a first rate of change for the detection signal (VB) for the period between the first and second timings. The processing part (1) also varies the first and second threshold values, finds the first rate of change for a plurality of periods, and, when a second rate of change between first rates of change for two adjacent periods is larger than a threshold value, detects the first or second timing of one period as a breakage location.