Patent ID: 8015878

Claim:
An optical sound or vibration detection system, the optical sound detection system comprising: a laser source for generating a laser beam; an optical fiber configured to receive a sound or vibration signal, the optical fiber comprising: a core that comprises a photoelastically active material; an input coupling port optically coupled to the laser source for coupling the laser beam into the core of the optical fiber; and an output coupling port for emitting laser light propagated through the core, the output coupling port configured to diffract the emitted laser light; an optical sensor at a detection plane spaced apart from the output coupling port and aligned to detect a portion of a diffraction pattern formed by the emitted laser light diffracted from the output coupling port of the optical fiber, the photoelastically active material of the optical fiber core adapted to modify the propagated laser light responsive to the sound or vibration signal such that the diffraction pattern is characteristic of the sound or vibration signal, the optical sensor adapted to produce a signal corresponding to the detected portion of the diffraction pattern; and a signal processor for processing the signal produced by the optical sensor.