A Mach-Zehnder Photonic MEMS Microphone with High Sensitivity, 1/F Noise Suppression, and Broadband Response

We propose a photonic MEMS microphone based on a fiber Mach-Zehnder interferometer (MZI) which optically transducers the membrane mounted at the end of a fiber under incident acoustics. As a result of the optical transduction, an outstanding sensitivity to weak acoustic waves is shown compared to commercial capacitive MEMS microphones. In addition, a flat noise spectrum with suppressed 1/f noise is demonstrated, which has been rarely reported before. It is also experimentally shown that the photonic MEMS microphone exhibits a broadband response from 20 Hz to 20 KHz, with the highest signal-to-noise ratio (SNR) up to 60.33 dB at 2 KHz. This is achieved using simple small-size photonic components without any amplification and processing circuits, showing its promising applications for high-sensitive sound detection.