In-Fiber Mach–Zehnder Interferometer Sensor for Ultrasound Sensing

Ultrasound sensing plays an essential role in various applications[1], including biomedical imaging, non-destructive testing, and underwater communication, and the realization of these versatile scenarios relies on suitable ultrasonic sensors. Traditional ultrasonic sensors, such as piezoelectric transducers, although widely used, often face limitations in terms of size, sensitivity, bandwidth and environmental robustness. In recent years, optical fiber sensors[2] have emerged as a promising alternative, offering numerous advantages such as compact size, broad bandwidth and immunity to electromagnetic interference. Here, we present an in-fiber Mach-Zehnder interferometer sensor specifically designed for ultrasound sensing.