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 10(4) 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.
Huang, L., Tian, H., Zhou, J., & Ji, Y. (2014). Design low crosstalk ring-slot array structure for label-free multiplexed sensing. Sensors (Switzerland), 14(9), 15658–15668. https://doi.org/10.3390/s140915658