A ZnO nanoparticle-coated long period fiber grating as a carbon dioxide gas sensor

Abstract

This study proposes a long period fiber grating (LPFG) with a zinc oxide (ZnO) nanoparticle layer for use as a carbon dioxide (CO2) gas sensor. Inductively coupled plasma (ICP) etching, corona treatment, and electrostatic spraying were used to fabricate this ZnO nanoparticle-coated LPFG CO2 gas sensor. Repeated gas sensor tests showed that, when a 15% CO2 mixture was injected (0.2 L/min) into a closed chamber into which the sensor had been placed, the CO2 gas was absorbed by the ZnO nanoparticle-coated LPFG sensor. In these tests, the transmission loss gradually decreased, and the maximum transmission loss was 2.039 dB. The concentration test results showed that as the concentration of CO2 introduced into the chamber was increased, the rate of the transmission loss change was increased in direct proportion. In addition, the sensitivity was 0.0513 dB/%. The results confirm that this low-cost ZnO nanoparticle-coated LPFG gas sensor was successfully applied to the measurement of CO2 gas. Therefore, the proposed ZnO nanoparticle-coated LPFG can be used to measure CO2 gas.