Locating acoustic emission with an amplitude–multiplexed acoustic sensor array based on a modified Mach–Zehnder interferometer

We report on an amplitude–division-multiplexed interferometric sensor array for locating acoustic emission. Preliminary experiments were carried out with a modified Mach–Zehnder interferometer consisting of two sensing arms and a reference arm and demonstrated a one–dimensional location accuracy of a few centimeters. The system can be extended for two– and three–dimensional location of acoustic emissions by the addition of one or two more sensing arms, respectively, in the interferometer.