Design of fiber acoustic sensors based on 33 coupler phase demodulation

In order to transport acoustic signal passively in some emergent cases, a fiber acoustic sensor was designed based on the principle of an optical fiber Michelson interferometer, processing techniques of elastic discs and optical fiber adhesion, 33 coupler phase demodulation. The expressions of three phase differences of output signals were presented, and the average phase differences were calculated based on the least square method. Simulation data and test data were acquired. Experimental results demonstrate that a fiber acoustic sensor can restore acoustic signal accurately and effectively within designed bandwidth. A fiber acoustic sensor can be used in emergent environments such as severe electro-magnetic situation. The test results verify the feasibility of a fiber acoustic sensor.