Patent ID: 9228890
Filing Date: 2016-01-05
CPC Classification: G01H

Claim Text:
1. A method of measuring an acoustic distribution, the method comprising: using a distributed acoustic sensor which comprises: calculating acoustic frequencies for all of the two or more fiber Bragg gratings disposed at the optical fiber to determine an acoustic distribution along the longitudinal direction of the optical fiber, by repeating a measurement step more than two times while changing an emission wavelength of the light source unit, the measurement step comprising: at the light source unit, a difference of two different emission wavelengths arbitrarily selected from among the two or more fiber Bragg gratings is greater than a maximum value Δλa of a wavelength width of an optical pulse output at each of the two or more emission wavelengths; and at the optical fiber, a minimum value Δλb of a reflection bandwidth of the two or more fiber Bragg gratings is greater than the maximum value Δλa of the wavelength width.