Grated waveguide-based optical cavities as compact sensors for sub-nanometre cantilever deflections, and small refractive-index changes

The paper reports on theoretical and experimental results of integrated optical (IO) cavities defined by grated waveguides in $Si_3N_4$ and Si, for the accurate detection of cantilever deflection and bulk index changes

Refractometric sensor based on silicon photonic wires

We have characterized the refractive index sensing properties of a compact refractometric sensor based on a grated silicon photonic wire. A resolution of $10^{-5}$ in refractive index has been measured

Tuning a racetrack ring resonator by an integrated dielectric MEMS cantilever

The principle, fabrication and characterization of a dielectric MEMS cantilever located a few 100 nm above a racetrack ring resonator are presented. After fabrication of the resonators on silicon-on-insulator (SOI) wafers in a foundry process, the cantilevers were integrated by surface micromachining techniques. Off-state deflections of the cantilevers have been optimized to appropriately position them near the evanescent field of the resonator. Using electrostatic actuation, moving the cantilevers into this evanescent field, the propagation properties of the ring waveguide are modulated. We demonstrate 122 pm tuning of the resonance wavelength of the optical ring resonator (in the optical C-band) without change of the optical quality factor, on application of 9 V to a 40 µm long cantilever. This compact integrated device can be used for tuning/switching a specific wavelength, with very little energy for operation and negligible cross talk with surrounding device

Integrated optics sensors for multi-sensing platforms

An overview is presented of research projects on optical sensing, in the Integrated Optical MicroSystems group of the MESA+ Institute for Nanotechnology at the University of Twente

Fabrication of microcantilever-based IO grated waveguide sensors for detection of nano-displacements

We propose a novel and highly sensitive integrated read-out scheme, capable of detecting sub-nanometre deflections of a cantilever in close proximity to a grated waveguide structure. A very compact and stable sensor element can be realized by monolithically integrating a microcantilever structure with the grated waveguide (GWG), using conventional layer deposition and sacrificial layer etching techniques. The platform integrating a high quality GWG and a low initial bending cantilever has been fabricated and characterized