Study of the Modeling of a Photonic Crystal Structure using COMSOL for the Design of a Temperature Sensor

Abstract

in this paper, we present a design of a two-dimensional photonic crystal-based temperature sensor (PhCs_2D). It is designed to detect temperature based on the effective modulation of the refractive index of silicon (n_Si). This temperature is monitored by the sensor for values ranging from T = 0°C to °T = 68°C. To analyze the detection principle, this two-dimensional square lattice structure is based on a Photonic Crystal Ring Resonator with a Swiss Cross in the middle (PCRR). The resonator is wedged between two parallel waveguides in a square lattice based on silicon rods immersed in the air, hence the refractive index equal to 3.46. This resonator has been studied as a promising solution due to the deformation, the extreme sensitivity as well as the variation of the position of the rods or cavities within the PhC resonators. It plays a relevant role in the detection of different temperature levels (T) over a wide dynamic range. We investigate the propagation and transmission of this structure that opens an optical channel drop filter (CDF) and the study is extended for tuning the channel filter (CDF) wavelength with temperature. The band diagram is analyzed and the transmission characteristics are obtained using plane wave expansion (PWE) and finite element method (F.E.M) respectively. This method evaluates the functional parameters of the sensor such as: resonance wavelength (λ_res), quality factor (Q), dynamic range, transmission efficiency and sensitivity (S). Our results show a resonance wavelength shift of the PCRR that increases linearly with increasing temperature. In this work, shift is used for sensor application. By F.E.M simulation under COMSOL software, we were able to obtain a resonance wavelength at 1640nm, a quality factor at 410 and a sensitivity of 370.6 pm/℃. The exceptional sensing capability makes PhC resonators a promising opto-mechanical sensing element to be integrated into various transducers for temperature sensing applications.