Design of a Narrow Band Filter Based on a Photonic Crystal Cavity for CO2 Sensing Application

Reyhaneh Jannesari; Thomas Grille; Gerald Stocker; Bernhard Jakoby

doi:10.3390/s23104958

Design of a Narrow Band Filter Based on a Photonic Crystal Cavity for CO₂ Sensing Application

Sensors (Basel). 2023 May 22;23(10):4958. doi: 10.3390/s23104958.

Authors

Reyhaneh Jannesari¹, Thomas Grille², Gerald Stocker², Bernhard Jakoby¹

Affiliations

¹ Institute for Microelectronics and Microsensors, Johannes Kepler University, 4040 Linz, Austria.
² Infineon Technologies Austria AG, 9520 Villach, Austria.

Abstract

This paper investigates the use of a miniaturized filter based on a triangular lattice of holes in a photonic crystal (PhC) slab. The plane wave expansion method (PWE) and finite-difference time-domain (FDTD) techniques were utilized to analyze the dispersion and transmission spectrum, as well as the quality factor and free spectral range (FSR) of the filter. A 3D simulation has demonstrated that for the designed filter, an FSR of more than 550 nm and a quality factor of 873 can be attained by adiabatically coupling light from a slab waveguide into a PhC waveguide. This work designs a filter structure that is implemented into the waveguide and is suitable for a fully integrated sensor. The small size of the device provides a strong potential for the realization of large arrays of independent filters on a single chip. The fully integrated character of this filter has further advantages such as reducing power loss in coupling light from sources to filters and also from filters to waveguides. The ease of fabrication is another benefit of completely integrating the filter.

Keywords: FDTD; PWE; band gap engineering; filter; mid-IR sensor; photonic crystal.

Grants and funding

This work was supported by the COMET-K2 “Center for Symbiotic Mechatronics” of the Linz Center of Mechatronics (LCM), funded by the Austrian federal government and the federal state of Upper Austria. Open Access Funding by the University of Linz.