Highly sensitive biochemical sensor based on photonic crystal ring resonator

In this paper a bio-chemical sensor is proposed based on photonic crystal ring resonator. The sensing characteristics of two types of ring resonator structures based on square and circular ring are studied and compared. The refractive index of coupling rods, inner ring rods and coupling as well as inner ring rods combined together are varied according to the sample which is to be sensed. Normalized transmission peaks at resonance condition are plotted against wavelength using finite difference time-domain (FDTD) technique. Plane wave expansion (PWE) method has been used to calculate the photonic bandgap of the proposed structures. It is found that both types of ring resonators have shown high sensitivity when the refractive index of sample is varied from 3.1 to 3.7 in steps of 0.2.