Multi-gas detection using Fabry-Perot interferometers on silicon chip

This work presents an all optical on chip integrated gas sensor array for sensing multiple gas simultaneously using non-specific polymers as the sensing material. The individual sensors are vertically etched into silicon. They are made of two Bragg mirrors forming a Fabry-Perot cavity which is functionalized with different polymers such as polyethylene glycol (PEG), SU-8 and polydimethylsiloxane (PDMS). Multi-gas detection was achieved for various gas mixtures of isopropyl alcohol (IPA), H2O, valeric acid and butanol. Using a linear model, we report limits of detection as low as 8.1 parts per million (ppm) for valeric acid within mixtures.