LAUSR

Concentric triple microring resonators with a single opening on the flexible SU-8 substrate are proposed and theoretically demonstrated for simultaneous detection of refractive index (RI) and pressure changes. Since an opening defect is introduced, the mode splitting occurs, which forms a symmetric and an asymmetric standing wave mode (SWM). The energy distribution of the two SWMs is quite different so that the sensitivities of the RI and pressure in the SWMs can be distinguished. The RI sensitivities of 186.37 nm/RIU and 107.69 nm/RIU and the pressure sensitivities of 1.42 pm/KPa and 1.07 pm/KPa are obtained corresponding to the symmetric and the asymmetric SWMs, respectively. By solving a second-order sensitivity inverse matrix, the change in RI and pressure can be measured simultaneously, thereby eliminating the influence of the strain-optical coupling effect in the field of biosensing application. The proposed structure has great potential in achieving simultaneous measurement of multiple parameters.