Fiber-optic interferometric sensor for the detection of acoustic emission within composite materials

Abstract

An optical-fiber Michelson interferometric acoustic emission sensor is described. The sensor uses ordinary singlemode fiber and is embedded in the composite material under test. Signals are demodulated through the active homodyne. This system provides a novel approach for material nondestructive evaluation.

A Fiber Optic Ultrasound Sensor for Monitoring the Cure of Epoxy

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<title>Extrinsic Fabry-Perot ultrasonic detector</title>

“…The change in transmission t in Eq. (1) is directly related to the thermal expansion of the cylinder material (416 stainless) via the relationship Ls = aJAT (2) a= 105cm/cm/0K L = 10 mm (length of hollow tube bonded to resonant cylinder)…”

Stabilization of optical Fabry–Perot sensor by active feedback control of diode laser

“…Optical fiber interferometric sensors have been shown useful in many applications, such as strain [1,2], pressure [3][4][5], material property analysis [6,7], and partial discharge detection [8,9]. Fiber Fabry-Perot interferometers (FFPI) have found increasing applications in the past decades for the detection and measurement of a large variety of physical parameters because of their high sensitivity and high-frequency response [3,4,10,11], showing advantages of being simple and compact in size, insensitive to environmental fluctuations, and suitable for point measurements with minimal cross talks.…”