A Mechanically Robust and Highly Sensitive Fiber-Optic Microphone

Conventional fiber-optic microphones (FOMs) are often limited by the tradeoff between sensitivity and mechanical robustness. To overcome this issue, a novel FOM based on a decoupled multilayer architecture is proposed and experimentally demonstrated. Through structural decoupling, the proposed design improves mechanical robustness without compromising acoustic sensitivity. Experimental results show that the proposed FOM achieves a sensitivity of −111.66 dB re 1 rad/$\mu $Pa/m, showing enhanced sensitivity compared with conventional structures. In addition, the sensor exhibits a high signal-to-noise ratio, good linearity, and lower susceptibility to assembly-induced stress and fiber damage. Application tests show that, compared with the conventional FOM, the proposed FOM reduces the automatic speech recognition (ASR) error rate by approximately 85% and demonstrates potential for equipment fault diagnosis, as exemplified by conveyor-belt monitoring. These results indicate that the proposed decoupled multilayer architecture provides an effective design strategy for high-performance fiber-optic acoustic sensing units.