This paper presents an optical fiber Mach-Zehnder interferometer configured as an ultra-sensitive sound detector.
We used a 633nm, 0.5 mW, He-Ne laser, two 3dB couplers, a few meter of telecomm fiber, an U-bench mount to
increase the sensitivity of the device and an acquisition system composed by a photodiode and an amplifier
connected to a laptop and to an oscilloscope. The optoelectronic device enables us to record acoustic signals from
sources at distances longer than 4 meters, converting the interference patterns induced by the sound waves into a
digital signal. The ease of its applicability, thanks to its small size and low weight, and its ultra-sensitivity makes
this laser microphone a very attractive solution to issues such as monitoring, no-detectable sensing and perimeter