ETCHED POLYMER OPTICAL FIBER BRAGG GRATINGS FOR ETHANOL VAPOR SENSING.

For the first time to the best of our knowledge, we report an ethanol vapor sensor based on etched fiber Bragg gratings (FBGs) written into step-index polymer optical fibers (POFs). The end of POF with grating was etched by immersion in a mixture of acetone and methanol (ratio 2:1). The etching rate was computed equal to 3.44 µm/minute. Then, the etched FBG was exposed to ethanol vapors mixed with dry air in different concentrations at room temperature. The sensitivity of this sensor is equal to 56 pm/% of ethanol vapor concentration. [ABSTRACT FROM AUTHOR]