Patent ID: 7505643

Claim:
An optical cable identification apparatus for identifying an optical cable by looping-back one end of each of two strands of optical fiber in an optical cable to be identified and applying a disturbance to the optical cable to be identified, the optical cable identification apparatus comprising: an optical unit configured to apply light to the two strands of the optical fiber in the optical cable to be identified after phase-modulating the light at a predetermined modulation frequency, interfere the light applied to the two strands in opposite directions, and detect light having a different intensity resulting from a phase difference due to the phase modulation and a phase difference due to the disturbance of the optical cable; a signal processor configured to receive a signal of the detected light, and demodulate the signal to an audio signal; and a sound output unit configured to receive the audio signal from the signal processor and transform the audio signal into a sound, wherein the signal processor is configured to delay outputting of the signal for a predetermined period to facilitate distinguishing the sound from the disturbance applied to the optical cable by a worker in a remote site.