A polymer waveguide resonator device for high-frequency ultrasound detection having a optical resonator coupled to a straight optical waveguide which serves as input and output ports. Acoustic waves irradiating the waveguide induce strain modifying the waveguide cross-section or other design property. As a consequence, the effective refractive index of optical waves propagating along the ring is modified. The sharp wavelength dependence of the high Q-factor resonator enhances the optical response to acoustic strain. High sensitivity is demonstrated experimentally in detecting broadband ultrasound pulses from a 10 MHz transducer.