A photonic crystal sensor array side-coupled to a linear waveguide with enhanced bandwidth

Abstract

We report a photonic crystal (PhC) sensor array consisting of six nanocavities which are side-coupled to a linear PhC waveguide. The design approach to cavities is based on rotating functional holes and changing their radius. Based on traditional linear waveguide, we also design a PhC waveguide with enhanced bandwidth by adjusting the holes on both sides of the central linear defect to weaken the Bragg reflector effect. With 3-D finite-difference time-domain (FDTD) method, the Q value and RI sensitivities for each sensor unit are adjusted from 3.67×105 to 5.41×106 and from 264 nm/RUI to 332 nm/RIU, respectively. Moreover, the free spectral range (FSR) values between every two adjacent sensing units are relatively larger enough compared with structures proposed previously. Accordingly, it provides the possibility to realize the integrated sensing and excellent sensing properties more effectively.