Photonic pressure sensor in silicon on insulator

A pressure sensor consisting of a Photonic Integrated Circuit (PIC) in Silicon-On-Insulator (SOI) technology. Sensor is based on the resonance shift principle. It contains an SOI waveguide-based ring resonator which is coupled to access waveguides by means of an MMI. The pressure under investigation acts on the locally thinned substrate, and alters the optical properties of the ring. The pressure can be retrieved by measuring the resonance wavelength of the ring structure. Using a standardized SOI layer stack, the properties of the sensor can be tuned by designing the geometry of the device. The data on our test structures is collected using Vertical Grating Couplers (VGCs) to launch and collect the optical signals. This enables us to do on-wafer testing without the need to dice the wafer, and to have a relatively large alignment tolerance. The final device will be equipped with V-groove fibre coupling interfaces, which is a proven and robust concept for CMOS-based PICs. The output signal of the device contains information about both pressure and temperature. In order to retrieve the actual pressure, we will account for the temperature-induced deformations of the PIC as well.