▎ 摘　　要

In this work, a study on a graphene oxide (GO)-coated fiber Bragg grating (FBG) sensor for ethanol detection in petrol is reported. The fiber Bragg gratings (FBGs) used in the present experiment were fabricated in-house using a high repetition rate (similar to 5.5 kHz), with frequency-doubled copper vapour laser output radiation. The sensor head was made by partially removing the cladding of the FBG region using hydrofluoric acid (HF) and then coating a GO layer onto it. This GO-coated etched FBG (EFBG) shows a significant enhancement (by a factor of ten) in the detection of ethanol in comparison with un-coated EFBG. The present sensor is based on the measurements of change in intensity of the reflection spectra with the variation of concentration of ethanol in petrol. Ethanol detection using this technique is almost independent of the sample temperature within C. A minimum of 0.5% ethanol in petrol was detected with GO-coated EFBG compared to 5% using un-coated EFBG. The sensitivity obtained with the GO-coated sensor was about 0.18 dBm/%.