Preparation and application of a novel chemical sensor based on mode-filtered light detection

A novel mode-filtered light chemical sensor is reported. This sensor operates by the detection of the mode-filtered light emanating from an uncoated optical fiber based on the changes of analyte refractive index. Compared to measuring changes in the transmitted light at the end of the fiber optic, it has great advantage in signal-to-noise ratio against a low background. A good result is obtained by detecting ethanol in alcohol solutions within the ethanol concentration range of 0–50% (v/v) (r=0.9972). The sensor is also applied to the measurement of the sample spirit, and the result is satisfactory.