An optical ring resonator sensor array module for a passive SONAR system. The module includes a supporting structure; a silicon substrate mounted on the supporting structure, and a top plate mounted over the silicon structure. The silicon substrate includes an optical waveguide having an input and an output and a plurality of optical ring resonators distributed across the silicon substrate to form a two-dimensional pattern. Each optical ring resonator is positioned adjacent to the optical waveguide and each has a different predetermined diameter. The top plate includes a plurality of diaphragms, one for each of the plurality of optical ring resonators. The diaphragms are distributed on the top plate such that each of the plurality of diaphragms is positioned over an associated one of the plurality of optical ring resonators. In addition, each of the diaphragms is configured to flex in response to externally applied acoustical pressure.