Cavity-coupled photonic crystal waveguide as highly sensitive platform for pressure sensing

In this paper, a pressure sensing platform based on cavity-coupled photonic crystal waveguide is proposed for hydrostatic pressure sensing. A label-free waveguide-cavity coupled with high-Q, is designed and analyzed to exhibit high sensitivity against wide range of pressures. The introduction of a cavity in the structure leads to a sharp resonance which makes it useful for detection of pressure change. It is observed through 2-D Finite Difference Time Domain (FDTD) method that the resonant wavelength of sensor is shifted by increasing the refractive index (RI) that is imposed by the hydrostatic pressure presence. The reported sensitivity and quality factor of the proposed platform are acceptable for wide range of pressures. The proposed design also demonstrates separated resonant peaks for different index (RI) and a good linear relation between the cutoff wavelength and the pressure, which allow high selective label-free pressure detection.