Abstract
In this paper we introduce a multi gas sensor system based on refractive index changes in a 2D slab photonic crystal. The sensor is formed by a L3 resonant cavity sandwiched between two W1.06 waveguides in the photonic crystal. The sensor configuration is similar to an Add-Drop filter structure. The transmission spectrums of the sensor with different ambient refractive indices ranging from n = 1.0 to n = 1.1 are calculated. The simulation results show that a change in ambient RI of Delta n = 0.0008 is apparent with a corresponding change in output wavelength of the sensor of 2.4 nm. The properties of the sensor are simulated using the 3D finite-difference time-domain (FDTD) method. The Q-factor of the sensor is also optimized, with highest values reaching over 30,000. The sensor system is hybrid integrated with a wireless RF chip which processes the sensor data and transmits them in effect turning the entire system into a wireless sensor mote.