Stress Modulation Using Si-based Optical Microring Resonator

With the development and application needs of Micro-opto-electro mechanical system(MOEMS) sensor in the areas of military engineering, aerospace, navigation, spaceexploration and so on, optical micro-ring resonator, as one of core components of MOEMSmechanical sensors, has important research value and application prospects in informationacquisition (stress/strain), information transmission(optical communication/opticalinterconnects), information processing (optical transceiver module) field. Its “light-force”sensitive nature is an important foundation to complete the high sensitivity of mechanicalsignals detection and for realizing miniaturization and integration research of the embeddedMOEMS optical force-sensitive sensors has great significance. So, the research on“light-force” sensing properties using Si-based optical micro-ring resonator was carried out.In this paper, a new stress-modulation mechanism of optical micro-ring resonator wasproposed and researched, theoretically. The influence of characteristic parameters of thewhispering gallery mode on the test signal was analyzed. The resonant spectrum shift ofoptical micro-ring resonator was proportional to the stress obtained, and the stress detectionsensitivity of the structure was related to the initial radius and the effective refractive index ofthe waveguide.In this paper, a new optical micro-ring resonator with cantilever beam was designed, and“light-force” sensitive units of the structure were analyzed by using optical simulationsoftware FDTD, R-soft and Comsol, to achieve the optimal design of the size andperformance of optical micro-ring resonator. The use of L-Edit completed the layoutproduction of optical micro-ring resonator, which preparation processing of sensitive unitswas discussed, designed, and ultimately completed the preparation of optical micro-ringresonator sensitive units.In the experiments, optical micro-ring resonator “Force-Optical” Test System Platform wasset up, and spiral micro-displacement pressurization device was designed. The “light-through” and stress modulation performance test experiment of a single loop, bicyclic cascade opticalmicro-ring resonator sensitive cell structure were completed. The characteristic of stress/strainsensitivity was calculated theoretically. For the single loop structure, two values of93.72pm/MPa and11.06pm/microstrain were obtained experimentally, and for the bicyclic cascadestructure, the value was184.73pm/MPa and18.04pm/microstrain obtained, which also wasverified by theoretical simulations. Finally, the new stress-modulation mechanism of opticalmicro-ring resonator employed as the intermediate sensing element was verified, which couldbe applied to the research on MOEMS mechanical sensors.