Fabrication of Etched Mono Mode Fiber for the Use as Chemical Sensor : Fabrication&analysis of etched single mode fiber for the use as chemical sensor based on evanescent field leakage theory

Optical and fiber optic chemical sensors have been reported extensively in literature on last two decades. Fiber optic sensors have since then found applications in chemical, biochemical, bio medical and environmental sensing. In general, Fiber optic sensors are classified as intrinsic and extrinsic type sensors. In the extrinsic type of sensors the optical fiber is only used as a means of light transport to an external sensing system. The intrinsic fiber optic sensors differ from extrinsic sensors, where light does not have to leave the optical fiber to perform the sensing function. In the intrinsic fiber optic sensors, the optical fiber structure is modified and the fiber itself plays an active role in the sensing function. Examples of intrinsic fiber sensors include, fibers with Bragg gratings, Long period gratings modified cladding or micro or macro bends. Some of these techniques use the evanescent field interaction for the sensing purpose. One of the accessing method of evanescent wave from the optical fiber is to reduce the cladding thickness. This book describes different aspects of chemical etching and fiber optic sensing.