Design low crosstalk ring-slot array structure for label-free multiplexed sensing

Abstract

We theoretically demonstrate a low crosstalk ring-slot array structure used for label-free multiplexed sensing. The proposed sensors array is based on an array of three ring-slot and input/output line defect coupling waveguides. Each ring-slot cavity has slightly different cavity spacing and different resonant frequency. Results obtained using two dimensional finite-difference time-domain (2D-FDTD) simulation indicate that the resonant frequencies of each sensor unit in response to the refractive index variations are independent. The refractive index sensitivity is 134 ~ 145.5 nm/RIU (refractive index unit) and the Q factors more than 104 can be achieved. The calculated detect limit lower than 1.13 × 10-4 RIU is obtained. In addition, an extremely small crosstalk lower than - 25.8 dB is achieved among the array of three ring-slot cavities. The results demonstrate that this multiplexed sensor array is a promising platform for integrated optical devices and enables highly parallel label-free detection. © 2014 by the authors; licensee MDPI, Basel, Switzerland.