Spiral waveguides on germanium-on-silicon nitride platform for mid-IR sensing applications

• Main Authors: Li, Wei, Anantha, P., Lee, Kwang Hong, Qiu, Hao Dong, Guo, Xin, Goh, Simon Chun Kiat, Zhang, Lin, Wang, Hong, Soref, Richard A., Tan, Chuan Seng
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2019
• Subjects: Integrated Optics Materials; Engineering::Electrical and electronic engineering; Integrated Optics Devices
• Online Access: https://hdl.handle.net/10356/106028; http://hdl.handle.net/10220/49573; http://dx.doi.org/10.1109/JPHOT.2018.2829988
• Institution: Nanyang Technological University

Spiral waveguides on a new germanium-on-silicon nitride (GON) platform with a wide transparency and a large core-clad index contrast for mid-infrared (mid-IR) sensing applications are demonstrated. Spiral waveguide sensors with a low bending loss on this platform enable compact sensors for mid-IR absorption spectroscopy. A minimum volumetric concentration of 5% isopropanol (IPA) in an IPA-acetone mixture is measured. This detection limit is three times lower than the counterpart waveguide, fabricated on the regular germanium-on-silicon platform with similar propagation loss at 3.73 μm wavelength. This silicon-compatible GON sensor is promising for applications such as environmental studies, industrial leak detection, process control, medical breath analysis, and many more.