Regular Article

Research on sensing characteristics of diamond multilayer waveguide structure racetrack micro-ring resonator

¹ School of Mathematics and Information Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066004, Hebei, P.R. China
² Institute of Electrical Engineering, Yanshan University, Qinhuangdao 066004, P.R. China

^* e-mail: gtydb666@163.com

Received: 15 October 2021
Received in final form: 10 December 2021
Accepted: 10 December 2021
Published online: 31 January 2022

Abstract

A racetrack micro-ring resonant cavity sensor based on the diamond's material is proposed in this paper. In the model, the vertical-section of the waveguide adopts a five-layer ridge-type waveguide structure based on CH₃NH₃PbI₃, SiO₂ and diamond, i.e. CH₃NH₃PbI₃-SiO₂-Diamond-SiO₂-CH₃NH₃PbI₃. First, on the basis of the resonant principle and coupled mode theory, this study investigated the light field intensity distribution characteristics of the integral resonant cavity, the longitudinal section of a single straight waveguide, the racetrack micro-ring, and the longitudinal section of the straight waveguide by using the finite element method in COMSOL. The analysis shows that the introduction of CH₃NH₃PbI₃ as an isolation layer can avoid the light scattering loss and leakage loss, and significantly enhance the filtering performance. In addition the sensing characteristics of the Add-drop racetrack resonator were further studied. Results showed that the structure could achieve a quality factor of 10⁵, and the sensitivity could reach 14833.33 dB/RIU. In the detection system with a signal-to-noise ratio of 30 dB, the detection limit was 2.02 × 10⁻⁷ RIU. Compared with the traditional All-pass single micro-ring resonator, the proposed structure shows advantages of high tenability, high sensitivity and low detection limit.