A high Q-factor photonic crystal microring-resonator based pressure sensor

Abstract In this work, a high Q-factor photonic crystal microring resonator (PC-MRR) based pressure sensor is reported. This sensor is designed based on SOI technology. The modelling and analysis of integrated optical (IO) resonator and mechanical diaphragm are carried out by using the Finite Element Method (FEM) and the Finite-Difference Time-Domain (FDTD) method respectively. The sensor consists of IO hexagonal microring resonator in between the two straight waveguides created by using a line defects and which is integrated on the diaphragm. When the pressure is applied to the flexible photonic crystal based ring resonator structure, the surface average stress changes to a higher value, which is estimated by FEM. The change in the stress causes a change in the refractive index of the IO resonator, in turn a shift in resonant wavelength at the drop port of the PC-MRR is observed for the applied pressure and this shift is red-shifted with increasing the pressure and it is observed by using the FDTD method. The device with a diaphragm is shown to exhibit high sensitivity of 1.37 nm/1 MPa and high Q-factor of 26,180 and also provides a linear wavelength shift in the output characteristics for the pressure range of 0 to 6 MPa.