Performance investigation of side-coupled interlaced symmetric-shaft-shape photonic crystal sensor arrays

•We design SSPhC sensor arrays which can be used in refractive index sensing.•The structure consists of four SSPhC cavities setting in cascade, realizing multiple sensing.•The highest sensitivity of the four sensor units is 398 nm/RIU.

We design symmetric-shaft-shape photonic crystal sensor arrays (SSPhCSAs) which can be used in refractive index sensing, and the performance of the structure is investigated. The structure consists of four symmetric-shaft-shape photonic crystal (SSPhC) cavities side-coupled to a W1 photonic crystal (PhC) waveguide. Each cavity has slightly different cavity spacing with different resonant frequency. By using two dimensional finite-difference time-domain (2D-FDTD) method, the simulation result obtained indicates the performance of the sensor arrays. The sensitivities of the four sensor units are 178, 252, 328 and 398 nm/RIU, respectively, with the detection limit of ~10−3. The crosstalk lower than ~20 dB is obtained.