DETECTION OF GASES WITH POROUS-CLAD TAPERED FIBERS

The detection of gases by the attenuation of the transmitted power in a multimode step-index tapered fiber with porous cladding is described . The results have been compared with those obtained for a uniform fib er. It has been shown that, for given fiber parameters, the absorptivi ty of the gas and its diffusion coefficient in the porous cladding, th e sensor response time, and the minimum detectable concentration of th e gas depend on the taper ratio. The higher the taper ratio, the small er the response time and the minimum detectable concentration.