Patent ID: 9287972
Filing Date: 2016-03-15
CPC Classification: G01H,H04B

Claim Text:
1. A distributed optical fiber sound wave detection device that uses an optical fiber as a sensor, comprising: an optical pulse emission unit that causes an optical pulse to be incident into the optical fiber from one end of the optical fiber; and a Rayleigh scattered light reception unit that receives Rayleigh scattered light produced inside the optical fiber by the incidence of the optical pulse, wherein the optical pulse emission unit outputs the optical pulse that is modulated using a code sequence which has a predetermined length based on a length dimension of the optical fiber and by which the optical pulse is divided into a plurality of cells of a predetermined width, and the Rayleigh scattered light reception unit includes: a phase variation derivation unit that performs demodulation corresponding to the modulation in the optical pulse emission unit on the Rayleigh scattered light and determines a phase variation thereof from the demodulated Rayleigh scattered light; and a sound wave detection unit that determines a sound wave that has struck the optical fiber from the phase variation determined by the phase variation derivation unit.