title: Study on the Sensing Coating of the Optical Fibre CO₂ Sensor.
abstract: Optical fibre carbon dioxide (CO₂) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO₂ optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and response time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2-3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use.
authors.affiliation: InPhoTech, 17 Słomińskiego St31, 00-195 Warszawa, Poland. kwysokinski@inphotech.pl.
authors.forename: Karol
authors.initials: K
authors.lastname: Wysokiński
authors.affiliation: InPhoTech, 17 Słomińskiego St31, 00-195 Warszawa, Poland. mnapierala@inphotech.pl.|IPT Safety, Ceramiczna St 8A, 20-150 Lublin, Poland. mnapierala@inphotech.pl.
authors.forename: Marek
authors.initials: M
authors.lastname: Napierała
authors.affiliation: Polish Centre for Photonics and Fibre Optics, Rogoźnica 312, 36-060 Głogów Małopolski, Poland. tstanczyk@pcfs.org.pl.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Stańczyk
authors.affiliation: InPhoTech, 17 Słomińskiego St31, 00-195 Warszawa, Poland. slipinski@inphotech.pl.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Lipiński
authors.affiliation: InPhoTech, 17 Słomińskiego St31, 00-195 Warszawa, Poland. tnasilowski@inphotech.pl.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Nasiłowski
keywords: CO2 sensors; absorption-based sensors; chemical sensors; gas sensors; indicator dyes; optical fiber sensors; silica gels; sol-gel coatings