Detection of Volatile Organic Compounds Using an Optical Fiber Sensor Coated with a Sol-Gel Silica Layer Containing Immobilized Nile Red

Arun Mallik, Dublin Institute of Technology
Dejun Liu, Dublin Institute of Technology
Gerald Farrell, Dublin Institute of Technology
Yuliya Semenova, Dublin Institute of Technology

Document Type Conference Paper

Proceedings Vol. 10323, 25th International Conference on Optical Fiber Sensors, Jeju, Republic of Korea, 2017.


A simple volatile organic compound (VOC) sensor based on a tapered small core singlemode fiber (SCSMF) structure is reported. The tapered SCSMF fiber structure with a waist diameter of 7.0 μm is fabricated using a customized microheater brushing technique. Silica based material containing immobilized Nile red was prepared by a sol-gel method and was used as a coating applied to the surface of the tapered fiber structure. Different coating thicknesses created by a 2-pass and 4-pass coating process are investigated. The experiments demonstrate that both sensors show a linear response at different gas concentrations to all three tested VOCs (methanol, ethanol and acetone). The sensor with a thicker coating shows better sensitivities but longer response and recovery times. The best measurement resolutions for the 4-pass coating sensor are estimated to be 2.3 ppm, 1.5 ppm and 3.1 ppm for methanol, ethanol and acetone, respectively. The fastest response and recovery time of 1 min and 5 min are demonstrated by the sensor in the case of methanol.