This paper presents the characterization of frequency response and mode shape at the 1st harmonic frequency of a Micro-Opto-Mechanical Acoustic Sensors (MOMAS) with a Mach-Zehnder Interferometer (MZI) readout system. In previous research, the static modeling and characterization has been demonstrated. In this paper, we investigate the capability of using MOMAS in ultrasound domain as a Micro-Opto-Mechanical Acoustic Sensor (MOMAS). We characterize the resonance frequency and mode shapes of three MOMAS by using a laser Doppler vibrometer(LDV) and a piezo shaker. The resonance frequencies range from 75kHz to 262kHz and the mode shapes are between a standard circular plate and a membrane mode. The results are compared with analytical models and finite element simulations to examine the effect of residual stress.