MODELING AND PERFORMANCE EVALUATION OF FERROCENE-BASED POLYMER CLAD TAPERED OPTICAL-FIBER GAS SENSORS

The possibility of utilizing certain polymers, known as variable-index materials, as cladding in tapered optical fibers for gas sensing is e xplored. We have shown that any small variation in the refractive inde x of the cladding of a tapered single-mode fiber has a direct influenc e on the transmission characteristic of the tapered region. A 4% devia tion in the refractive index of a certain polymer is obtained upon the exposure of the polymer to ammonia. Sensitivity, repeatability, and s electivity of several fabricated sensors are also illustrated. (C) 199 8 Society of Photo-Optical Instrumentation Engineers.