Abstract

The evanescent wave coupling of a microring resonator is controlled by changing the gap distance between the bus waveguide and the microring waveguide. However, the interdependence of the bus waveguide’s width and the coupling is not well understood. In this paper, we investigate the dependence of coupling strength on the bus waveguide’s width. The strength of the evanescent wave coupling is analytically calculated using coupled-mode theory (CMT) and numerically calculated by three-dimensional finite-difference-time-domain (FDTD) simulation. The analytic and numerical simulation results show that the phase-matching condition in evanescent wave coupling does not provide maximum coupling strength, because both phase-matching and mode confinement influence the coupling. The analytic and simulation results for the evanescent coupling correspond to the experimental results. The optimized bus-waveguide width that provides maximum coupling strength results in intrinsic quality factors of up to 1.3 × 10⁶. This study provides reliable guidance for the design of microring resonators, depending on various applications.

© 2021 Optical Society of Korea

Analysis of coupled microcircular resonators coupled to a bus waveguide with high output efficiency

Shi-Jiang Wang, Yue-De Yang, and Yong-Zhen Huang
Opt. Lett. 35(12) 1953-1955 (2010)

Micro-resonator with metallic mirrors coupled to a bus waveguide

Steve Zamek, Liang Feng, Mercedeh Khajavikhan, Dawn T. H. Tan, Maurice Ayache, and Yeshaiahu Fainman
Opt. Express 19(3) 2417-2425 (2011)

Combining FDTD and coupled-mode theory for self-pulsing modeling in coupled nonlinear microring resonators

Nessim Jebali, Loïc Bodiou, Joël Charrier, Andrea Armaroli, and Yannick Dumeige
J. Opt. Soc. Am. B 37(9) 2557-2563 (2020)

Z-domain modeling approach of a multilayer sextuple-coupled micro-ring resonator with 1 × 5 input–output bus waveguides as optical filters

Binshati Chatterjee and Sanjoy Mandal
Appl. Opt. 58(28) 7868-7877 (2019)

Study of coupling loss on strongly-coupled, ultra compact microring resonators

Chih-Wei Tseng, Chih-Wei Tsai, Kaung-Cheng Lin, Ming-Chang Lee, and Yung-Jui Chen
Opt. Express 21(6) 7250-7257 (2013)