Investigations On A Optical Bean-shaped Ring-resonator Sensor In SOI Platform

With the development of optical waveguide devices, optical sensor become a promising platform to in many applications, including environment protection, medicine diagnose and biological product. Silicon photonics devices are widely used for sensing scenarios owing to the overlap interaction between optical evanescent wave and bio-analytes absorbed on device surfaces or in the surrounding medium. The purpose of this thesis is to develop a high-performance optical sensing system based on a silicon-on-isolator platform.Firstly, we design a novel optical bean-shaped resonator sensor integrated with MZI structure(BR-MZI). We calculate the total transmission spectra by transfer-matrix method. Also we optimize the device design following the interference conditions of MZI and the bean-shaped resonator. We analysis the performance of our BR-MZI device, such as the sensitivity, limit of detection, extinction ratio and Q factor by MATLAB. The sensor device with 30×12 μm2 footprintprovides a high sensitivity of 677.1 nm/RIU. The limit of detect is 10-6 and the quasi- free spectra range is 469 nm.Secondly, we push our design further by many different methods, including two cascade BR-MZI, a BR-MZI with two coupling straight waveguides, a two cascade BR-MZI with two coupling straight waveguides and a two-channel BR-MZI. By careful optimizations, we finally can obtain even better performances with regard to the sensitivity and quasi-FSR.Finally, we investigate how to couple light from silicon nano-waveguide to optical fiber. We simulate the two-dimension and three-dimension models of grating coupler by using Opti FDTD software and Rsoft software. In our three-dimension model, a 38% coupling efficiency is achieved with a twenty-one degrees offset in the vertical direction.The grating coupler design and BR-MZI novel device with a high sensitivity in a wide wavelength span and its interesting cascade ability show a great potential to the future ultra-compact and high-sensitivity integrated sensor arrays.