A wide variety of fiber devices can be created by adding special coatings on tapered sections of optical fibers. In this work we present the fundamentals for the fabrication of tapered optical fibers coated with functional polymers. The required aspects of light propagation in tapered sections of optical fibers are introduced and the relevant parameters enabling light interaction with external media are discussed. A special case of interest is the addition of polymeric coatings with prescribed thicknesses in the tapered sections allowing for adjusting the light propagation features. We assess the use of liquid polymer coatings with varying thicknesses along the taper profile that can be tailored for tuning the transmission features of the devices. Hence, we introduce a methodology for obtaining coatings with predefined geometries whose optical properties will depend on the polymer functionality. As demonstrated with numerical simulations, the use of functional polymer coatings in tapered optical fibers allows for obtaining a wide variety of functionalities. Thus, controlled polymer coating deposition may provide a simple means to fabricate fiber devices with adjustable transmission characteristics.
Part of the book: Fiber Optics