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.