Sensitivity limits of guided modes in silicon integrated waveguide-based sensors

摘要

We present a numerical study of the sensitivity of guided modes due to the presence of small mechanical vibrations. Analysis is performed utilising finite elements method (FEM) with help of both 2D and 3D models, where changes to the field distributions associated with the guided modes are computed in order to read the position of a conducting plate suspended over a waveguide. The sensitivity related to the guided modes is analysed and a possibility to improve the sensitivity by combining the sensing effect of several modes is investigated. By utilising FEM, the optical response to the system is studied in terms of both indiviudal response to the perturbation and the collective response by using the concept of multimode interference (MMI). The preliminary models predict a theoretical sensitivity limit of 2.4 %m in terms of normalised power transmission for a MMI of only 4.1 μm length.