We motivate how integrated waveguides (WGs) can be part of an on-chip non-dispersive infrared sensor system for environmental sensing. We report the hurdles in maintaining WG quality when integrating emitter and detector structures on the same chip. Thus, we introduce the concept of how to determine the intrinsic loss and a process scheme to protect WG structures from damage caused during fabrication. This could pave the way to systems for environmental sensing with a minimal footprint.

We investigated the feasibility of indium tin oxide (ITO) as an alternative plasmonic material to replace noble metals for sensing applications in the mid-infrared region. An ITO-based plasmonic slot waveguide was numerically designed and analysed for a wavelength of 4.26 µm, which is the absorption band of CO₂. As the proposed structure shows low propagation lengths, we concluded that ITO appears not to be an appropriate candidate for plasmonic waveguiding systems.