For the past 40 years, acoustic sensing has been a major avenue for the growth of interfero- metric fiber-optic sensors. Fiber-optic acoustic sensors have found uses in military, commer- cial, and medical applications. An interferometric fiber-optic acoustic sensor is presented utilizing the Michelson interferometer configuration with Faraday mirrors to eliminate po- larization fading. A 3 × 3 coupler is used as the beamsplitting component, and a symmetric demodulation algorithm is applied to recover the phase signal. This sensor has a theoretical resolution of 5.5 pico-strains and room to improve. Such improvements are discussed in the conclusion. / Master of Science / For the past 40 years, acoustic sensing has been a major avenue for the growth of fiber-optic sensors. The optical fiber itself acts essentially like a microphone that is sensitive to acoustic emissions in the audible range up into the ultrasonic range. Because of the fiber’s innate resistance to harsh environments, fiber-optic acoustic sensors have found uses in military, commercial, and, more recently, medical applications. The extremely high sensitivity achievable with a fiber-optic acoustic sensor is demonstrated using a simple arrangement of now readily available fiber-optic components and digital signal processing.