Ring Resonator-Based Optical Filter and Splitter for Integrated Photonics

Author : Jamal Derbali

Abstract :This work presents a novel metadevice integrated onto an optical platform that simultaneously functions as both an optical filter and an optical splitter, leveraging a dropped cavity-ring resonator configuration within a two-dimensional square photonic crystal (2D-PC). The device structure consists of two waveguides coupled via a ring resonator embedded in a defect cavity. For filtering, the PC is composed of silicon rods (ε=12), while for splitting, it utilizes alumina rods (ε=8.9). By precisely engineering the geometrical parameters, the waveguide width (w) and, critically, the ring resonator thickness (g), the transmission characteristics are dynamically controlled. Simulation results using the Finite Difference Time Domain (FDTD) method demonstrate that for specific g values, the structure acts as a high-efficiency filter, selectively transmitting one resonant mode while strongly attenuating another. Furthermore, by tuning g, the same core structure transitions into a highly efficient 1×3 optical splitter, directing nearly 99% of the incident light to a single output port or equally distributing it among all three output ports, depending on the chosen g. This dual-functionality, achieved through simple geometric tuning without altering the fundamental architecture, offers a promising route for compact, multi-functional components in integrated photonic circuits for applications such as wavelength division multiplexing and signal routing.

Keywords :Photonic Crystal, Ring Resonator, Optical Filter, Optical Splitter, Dropped Cavity, FDTD, Integrated Photonics.

Conference Name :International Conference on Dimensionless Physical Quantities, Physics and Mathematics (ICDPQPM -25)

Conference Place Abha, Saudi Arabia

Conference Date 27th Oct 2025