Design of Temperature Sensor Based on One-Dimensional Photonic Crystal Containing Si–BGO Layer

Abstract

This paper describes the theoretical investigation of enhancement in temperature sensitivity using one-dimensional (1D) symmetric defective photonic crystal (PC) containing Si (Silicon) and Bi4Ge3O[Formula: see text] (Bismuth Germanate, BGO) material. The proposed sensor consists of a defect layer (air defect) sandwiched between two 1D-PCs with a symmetrical and asymmetrical structure composed of Si and BGO, respectively. Sensor performance has been evaluated by calculating the transmittance spectra of the proposed structure. In order to obtain the transmittance spectra, a transfer matrix method (TMM) is employed. The principle of temperature sensing is based on the shift in the resonant wavelength (or peak) of the transmission mode with a change in temperature. This is due to the temperature-dependent refractive index of the Si and BGO layers. Analysis of the transmittance spectra shows that temperature sensitivity of 1D-PC structure can be enhanced by using a symmetric defective PC with and without an external defect layer over asymmetric defective PC. It is found that symmetric defective PC with and without defect shows sensitivity equal to 0.173[Formula: see text]nm/∘C and 0.140[Formula: see text]nm/∘C, whereas asymmetric defective PC shows 0.125[Formula: see text]nm/∘C, for the same parameters. Further, the results show that symmetric defective 1D-PC (without the presence of any external defect layer) gives a higher Q-factor than a symmetric and asymmetric defective 1D-PC with an external defect layer. The proposed structure is cost-effective, easy to fabricate and compact in size.