Additional PVC or similar protective coatings can be made by extrusion after the drawing process. Typical coating materials used are acrylate, silicone and (for fibers with high temperature resistance) polyimide, but there are also carbon and metal coatings for special applications. for telecom fibers frequently consist of two or more different layers for optimum suppression of microbends. Multiple coating layers may be applied using a suitable sequence of coating cups (applicators) and curing facilities. For that purpose, the fiber can (after having be cooled down enough) be fed through a coating applicator, followed by a curing oven and/or a UV irradiator for curing the coating. ![]() A protective polymer coating is usually applied directly before winding up the fiber.īefore the fiber is wound up, one usually applies a thin polymer coating for mechanical and chemical protection. This also leads to a quite constant fiber core diameter, which is important for various reasons. During the pulling process, the fiber diameter is held constant by automatically adjusting the pulling speed (and possibly the furnace temperature) with an automatic feedback system (containing a diameter monitor just below the furnace). It is then wound up on a spool, using a spinning machine. When the preform is heated in a furnace (oven) at the top of the drawing tower, such that its bottom part becomes soft, a thin fiber can be pulled out of the bottom of the preform and cooled to become solid. Carefully controlled pulling is required for obtaining a constant fiber diameter. Along its axis, the preform contains a region with increased refractive index, which will form the fiber core. The preform is a glass rod with a diameter between about 1 cm and 10 cm and roughly 1 m to 2 m length. Most glass fibers are fabricated by pulling from a so-called preform in a fiber-drawing tower, an apparatus which is typically several meters high. Fiber Pulling from a Preform Figure 1: A fiber drawing tower. In the following, this article first discusses how a fiber can be made from a preform, then how preforms are fabricated, and finally methods not requiring a preform. based on extrusion, are common for plastic optical fibers and for some specialty glasses. ![]() Preform-based methods are most important at least in the context of glass fibers (which are mostly silica fibers), whereas direct methods, e.g. In a first step, these can be divided into methods involving a so-called fiber preform and methods of direct fiber production. There is a wide range of methods for the fabrication of optical fibers. How to cite the article suggest additional literature Encyclopedia > letter F > Fiber fabrication Fiber Fabricationĭefinition: the fabrication of optical fibers
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