Mid-infrared absorption gas sensing using a silicon strip waveguide

Christian Ranacher, Cristina Consani, Andreas Tortschanoff, Reyhaneh Jannesari, Markus Bergmeister, Thomas Grille, Bernhard Jakoby

Research output: Contribution to journalArticlepeer-review


Optical sensing is an emerging field for photonic microsystems that operate in the mid-infrared spectral range. In this work we present a photonic gas sensor based on infrared evanescent field absorption, designed for CO2 sensing. The sensing structure comprises a strip waveguide on a silicon nitride layer. A modal analysis was performed using the finite element and the finite difference time domain method. The fabricated waveguides were characterized and the concept was validated with quantitative CO2 measurements. The measured transmittance at various CO2 concentrations was fitted using the Beer–Lambert law, and the results proved that the presented concept is feasible for CO2 gas sensing. The devised demonstrator device allowed to detect CO2 concentrations down to 5000 ppm, which is the workplace exposure limit in most jurisdictions.
Original languageEnglish
Pages (from-to)117-123
Number of pages7
JournalSensors and Actuators A: Physical
Publication statusPublished - 1 Jul 2018


  • Evanescent field absorption
  • Integrated silicon photonics
  • Optical gas sensing
  • Silicon waveguide


Dive into the research topics of 'Mid-infrared absorption gas sensing using a silicon strip waveguide'. Together they form a unique fingerprint.

Cite this