A bio-inspired optical directional microphone with cavity-coupled diaphragms

A bio-inspired acoustic sensor for sound source localization is presented, mimicking the internally coupled ears found in many terrestrial vertebrates and insects. It consists of two aluminum diaphragms coupled by a U-shaped cavity and detected by a low-coherence fiber optic interferometer system. A large-scale prototype with a center-to-center separation of 1″ is fabricated and experimentally demonstrated to amplify the interaural phase difference by a factor of 2 to 4 for a wide frequency range (0.5–2 kHz), which agrees well with simulation. This work presents a mechanism of using cavity-coupled diaphragms to develop acoustic sensors for sound source localization.