Fiber-Wrapped Mandrel Microphone for Low-Noise Acoustic Measurements

A low-noise fiber optic microphone has been developed using a fiber-wrapped mandrel as the acoustic transducer. The microphone has an average sensitivity of 0.206 rad/Pa between acoustic frequencies of 50 Hz and 16 kHz and a minimum detectable pressure as low as 3 μPa/Hz
^1/2
. The noise floor of the microphone approaches the thermal limit set by the length of fiber used in the system. Performance of the microphone is comparable to a current state-of-the-art condenser microphone. The design is small, lightweight, and readily packaged into multiplexed systems, making it an ideal candidate for use in acoustic sensor array systems.