Demonstration of a high-temperature fiber-optic gas sensor made with a sol-gel process to incorporate a fluorescent indicator

To make a gas sensor suitable for use at high temperatures, we have used a sol-gel-processing technique to bond a copper-exchanged zeolite fluorescenc e indicator onto the end of an all-silica optical fiber. Experimental resul ts from single-fiber prototype sensors show they can be used to measure eit her the oxygen concentration or the equivalence ratio for gas mixtures cont aining weak or strong reductants, respectively. (C) 1999 Optical Society of America. OCIS codes: 060.2370, 160.6060, 300.2530.