METHOD FOR CONTRASTING COATED OPTICAL FIBER AND DEVICE FOR CONTRASTING COATED OPTICAL FIBER

摘要

PURPOSE: To obtain a device for contrasting coated optical fibers capable of easily changing the frequency of a low-frequency signal without discriminating the contrasting of the coated optical fibers with light signals exclusive of the light signal modulated by the prescribed low-frequency signal. CONSTITUTION: This device has a light receiving element 13 which receives the leakage light of the incident light signal modulated by the prescribed frequency on the coated optical fiber by a light emitting element 11 and outputs the electric signal corresponding to the received leakage light, a contrast discriminating means which compares the modulation frequency of the output signal of the light receiving element 13 and the prescribed frequency and outputs the signal when coincidence is attained and a measurement result circuit 22 which announces the contrast of the coated optical fibers in accordance with the output signal of this contrast discriminating means.