Improved Design of a Ring Resonator Based Notch Filter with High Quality Factor and Sensitivity

Optical filtering is essential in various application areas due to its large bandwidth, tunability, rapid reconfigurability, and high extinction ratio. Applications such as high-speed optical connections, consistent detection technologies, optical communication systems, and wireless telecommunication systems, have all advanced in recent years. These advanced technologies require high stability, flexibility, compact sizes, narrow bandwidth, high sensitivity, and quality factor. Specifically, microring resonators (MRR) with high quality factor, high sensitivity, and compact sizes are essential for optical filtering, lasers, and sensing applications. This paper focuses on improving the sensitivity and quality factor of the generic ring resonator based notch filter. The general design has been improved, as integrating the basic notch filter into new and existing systems will reduce complexities and complications. The ring resonator structure consisted of a looped and a straight waveguide and the gap between the waveguides is minimum ensuring high coupling. A quartz cladding and a variable core material have been used. A highly enhanced quality factor, followed by higher sensitivity, is achieved by varying the core width and the core refractive index correspondingly. For the range of wavelengths of 1520nm to 1650nm, it is observed that the quality factor is refined to a maximum of 2254.043, and the sensitivity is improved to a value of 524.3nm/RIU, for the optimum core width of 0.24 μm and core material silicon carbide with refractive index 2.6353.