APPARATUS FOR TESTING OPTICAL FIBER BY USING DETECTOR HAVING VIRTUALLY BROADENED DYNAMIC RANGE

摘要

An optical fiber testing apparatus for testing an optical fiber as to presence and location of a fault such as breakage by inputting a pulsed coherent light beam to the optical fiber and synthesizing a return light beam reflected back from the optical fiber with a reference light beam having a frequency deviated from the pulsed light beam by a predetermined amount, wherein the synthesized waveform is detected through optical heterodyning. The electric signal obtained from the heterodyning detection is detected by an envelope detector, of which dynamic range is effectively virtually broadened by using correcting data prepared previously. The optical fiber test can be accomplished through a single measurement without involving expensiveness of hardware.