Optical fiber acoustic sensor

A Synchronous Phase-Detection System for an Optical Interferometric Sensor

“…The two most common fiberoptic sensors are the acoustic sensor [2,3] and the rate gyroscope [4,5]. The basic concepts of these two sensors are described in the following passages.…”

“…If E s and E r are assumed to be linearly polarized in the same direction, the power of the incident field is linearly proportional to |EjJ 2 and the detected output s(t) is linearly proportional to the field power or s(t)a|E.I 2 = E.E. , where K is a constant of proportionality relating to the efficiency of the detector.…”

Sensitivity analysis of the Sagnac-effect optical-fiber ring interferometer

“…The squared terms of the signal and scattered light are of the same form, i.e.,~~~~~~~~~~~~~~~~~~~~ (5) Recalling that the scattering processes are assumed reciprocal so that each scattered component in ttte CW direction is equal to that in the CCW direction, then , by defining an optical intensity I ~A j 2 , we get, for the averaged photodetector output current, the expression (6) where D -~'-is the detector conversion factor with hv -quantum efficiency of the detector v -laser frequency q -electronic charge h -Planck ' s constant and…”

Advanced fiber-optic acoustic sensors

“…These features make fiber-optics a very promising technology for acoustic sensors. The first systems were reported in 1977 by Bucaro et al and Cole et al [1][2][3]. Their preliminary works marked the beginning of fiber-optic acoustic sensing that, since then, continued to be developed.…”