ABSTRACT
An Optical Fiber Chemical Sensor (OFCS) detects the existence of and measures the concentration of a compound in a sample through detecting the interaction of the compound with light propagating inside an optical fiber. When a light beam is injected into an optical fiber, the light travels down the fiber through a series of total internal reflections at the interface of the optical fiber core and cladding layer. Three types of special optical fibers, porous solid optical fibers (PSOF), liquid core waveguides (LCW), and hollow waveguides (HWG), have been used in designing Active Core-OFCS (AC-OFC). Some very sensitive chemical sensors have been developed using these special optical fibers. An optical fiber ammonia sensor has been developed by using a short piece of such a porous glass fiber impregnated with a pH indicator as a transducer. Photonic band-gap HWG is a recent development of optical fibers. HWG-based AC-OFCS have the potential to achieve high sensitivity and fast response detection.
