Fiber-optic chemical sensor using polyaniline as modified cladding material

An intrinsic fiber-optic chemical sensor is developed by replacing a certain portion of the original cladding with a chemically sensitive material, specifically, polyaniline. Both the light absorption coefficient and the refractive index of the polymer change upon its exposure to different chemical vapors. These changes induce the optical intensity modulation of the transmitted optical signal. Therefore, the developed structure is proposed for optical sensor applications. The performance of the sensor depends on the optical properties of the replaced cladding material, the cladding modification process, and the properties of the transmitted light within the optical fiber.