Final Project MAE 546 Interferometry-Based Fiber Optic Microphone Using Graphene DiaphragmIntroduction of Conventional Microphones and Fiber Optic MicrophoneMicrophone is a type of device that includes an acoustic sensor -electrical that converts sound into electrical signals. Conventional microphones use the mechanism of electromagnetic induction (dynamic microphone) or capacitance variation (condenser microphone). Microphones have numerous applications in our daily lives, such as telephones, hearing aids, engineering, radio and television broadcasting, voice recognition and so on. Instead of detecting changes in capacitance or magnetic field as with conventional microphones, the fiber optic microphone converts acoustic waves into electrical signals by detecting changes in light intensity. It can achieve a wide dynamic and frequency range, compared to conventional high-fidelity microphones. A great advantage of the fiber optic microphone is the absence of reaction or influence by electric, magnetic, electrostatic or radioactive fields. It is therefore ideal for use in areas where conventional microphones are ineffective or dangerous, such as industrial turbines or magnetic resonance environments. Additionally, the fiber optic microphone is resistant to environmental changes in temperature and humidity and can be manufactured for any directionality. The distance between the microphone light source and the photodetector can be several kilometers without using preamplifiers or other electrical devices, which makes fiber optic microphones suitable for industrial acoustic monitoring. Possessing these qualities, fiber optic microphones are used in some specific applications such as infrasound monitoring and noise cancellation. They have...... half of the paper......)/(3r^4 (1-σ^2 )D(∂I/∂X))The fundamental resonant frequency f of the graphene diaphragm can be expressed asf=t/(2πr^2 ) √(E/(12ρ(1-σ^2)))The sensitivity of the microphone is given by ∂X/∂P×∂I/∂X and the unit is W/ Pa. The displacement sensitivity ∂I/∂X could be determined by the optical properties of the fibers and needs to be measured. From previous research, the measurement can be performed by mounting fibers on a manually controlled micrometer transducer and then placed near a mirror mounted on a piezoelectric transducer. Advantages and Discussion The ultra-small thickness of graphene could significantly improve the pressure sensitivity of FPI sensors. Furthermore, graphene has much better mechanical strength than other thin-film materials, including metal and silica, and can withstand static pressure up to MPa. DiscussionMicrophone shadow effects.