An Optical Fiber Fabry-Perot Microphone Based on Corrugated Silver Diaphragm

A corrugated silver diaphragm-based optical fiber microphone (OFM), formed by extrinsic Fabry-Perot interferometric structure, was proposed. The sensor's sensitivity was improved by releasing diaphragm's initial stress with the help of corrugations. A simple “gray-scale exposure” method was proposed to fabricate the corrugation. Experimental results indicated that the mechanical sensitivity of the fabricated corrugated diaphragm (CD) was 52 nm/Pa, which was twice that of the planar diaphragm under the same parameters. Other characteristics of the fabricated microphone were also tested in detail. The proposed CD-based OFM showed the advantages of high sensitivity, simplicity and low cost, which was expected to be applied in the field of weak acoustic sensing.