Photonic crystal-based high performance cascaded micro ring resonator using topological interface state: design, analysis, and application

We propose a photonic crystal-based cascaded micro ring resonator to increase the quality factor using the concept of two-dimensional constrained topological edge states. The topological features of the photonic crystal are used to acquire the increased quality factor by finite-difference time-domain (FDTD) numerical simulation. Two micro ring resonators with different band topologies that come together at an interface and are confined inside a slab of dielectric material give rise to a topological edge state. The transmission dropout issue arises whenever the quality factor is enhanced in a conventional photonic system, which can be improved remarkably by employing the present approach. As an application, the proposed topological edge state structure is used to increase the sensitivity and quality factor of the pressure sensor. In FDTD simulation, resonance wavelength shifts are employed to calculate the pressure of a system, while structural deformation and refractive index change are used as input parameters. The proposed structure is incredibly small and suitable for photonic integrated circuits.