Optical fiber sensor using tailored porous sol-gel fiber core

Novel techniques for fabricating a porous sol-gel fiber, doping chemical reagent into the fiber, and constructing an optical fiber chemical sensor using the porous fiber as a transducer, have been invented. A moisture sensor employing a CoCl₂ doped porous sol-gel fiber as a transducer has been constructed as an example. The test result of the moisture sensor verified a conclusion from theoretical analysis. That is an optical fiber chemical sensor using an active fiber core as a transducer should have a much higher sensitivity than that of active coating based sensor.