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Updated: May 10, 2026

Fabrication of Silica Ultra High Quality Factor Microresonators
Published on: July 2, 2012
Design and modeling of eye-shaped double-slot GaAs microring resonator for CO2 sensing
Faezeh Pakfetrat1, Mahdi Bahadoran2, Shadab Dabagh3,4
1Department of Physics, Shiraz University of Technology, Shiraz,, 31371555, Fars, Iran.
Abstract:
Monitoring of CO2 is crucial because of its profound impact on both environmental and human health. A novel highly sensitive refractive index (RI) sensor, utilizing a double-slot microring resonating structure, has been designed and numerically assessed for the sensitive detection of gas media. The structure consisted of a circular microring resonator nested in a racetrack resonating configuration mimicking the structure of an eye-shaped microring resonator (ESMRR). This system was simulated and designed for a GaAs double-slot core waveguide deposited on a suitable Al0.5Ga0.5As substrate. Optical transfer function of ESMRR and related equations were derived using Mason rule, while the numerical analysis was performed using the variational finite difference time domain (var- FDTD) method. The free spectral range (FSR) was extended to 137.68 nm that led to a remarkable bulk sensitivity of 1217.39 nm/RIU and a resolution of 4.93 × 10-6 RIU. The proposed sensing structure was envisioned for CO2 sensing and demonstrated an impressive sensitivity of 24.4 pm/ppm for CO2 detection with an estimated detection limit of 0.82 ppm.
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