Future applications of ultrasonography in (bio-)medical imaging require ultrasound sensor matrices with small sensitive elements. Promising are opto-mechanical ultrasound sensors (OMUS) based on a silicon photonic ring resonator embedded in a silicon-dioxide acoustical membrane. This work presents new OMUS modelling: acousto-mechanical non-linear FEM and photonic circuit equations. We show that initial wafer stress needs to be considered in the design: the acoustical resonance frequency changes considerably and OMUS sensitivity differs for up-or downwards buckled membranes. Simulated acoustical resonance frequency agrees well with measurements, assuming realistic SOI wafer stress. Measured sensitivity showed large device-to-device variation and simulations agree within this order of magnitude. We conclude that careful modeling of stress is necessary (b) for the design of robust and sensitive sensors.

This paper presents a new type of accelerometer, the Micro-Opto-Mechanical Accelerometer (MOMA). Micro-opto-mechanical pressure sensors and microphones demonstrated already the excellent sensitivity on a very large pressure range which is possible thanks to their photonic read-out (1Pa precision over kPa range). In this paper, we design in the same technology an optical accelerometer using analytical equations as well as Finite Element simulations. The model takes into account the mechanical deformation of the device, its effect on the elongation of the waveguide, and also includes the optical losses. Using the opto-mechanical model, an optimum design is obtained varying device dimensions and waveguide positions in order to increase the accelerometer sensitivity.

Micro-opto-mechanical Microphone (MOMM) based on integrated optical Mach-Zehnder interferometers (MZI) are promising for future application in medical environments. However, the design of next generation MOMM systems on chip remains challenging due to the intrinsic multi-physics characteristics related to acoustic, mechanical, optical and electrical effects. We therefore developed a methodology composed of acoustic, mechanic, optical, and electronic sections for fast design of high performance MOMM systems. The feasibility has been demonstrated as the operational characteristics of the fabricated MOMM (i.e. resonance frequency, dynamic range, the sensitivity and SNR) align well with the measured references.