New Methods for Evaluating Optical Fiber Coating Materials

Optical fibers are crucial in the field of telecommunications, offering the advantages of low loss. broad bandwidth, fine diameter, light weight, freedom from electromagnetic induction, freedom from crosstalk, and efficiency in resource consumption. In comparison to the copper conductors used in conventional telecommunications cables, however, they are at a disadvantage in terms of their low mechanical strength, which makes them brittle. From the processes of fiber drawing, coating and cabling to the laying of the cables, they are subjected to tensile force, and subsequently, under a variety of environments, they must have superior static and dynamic fatigue characteristics. For this reason optical fibers, immediately after drawing, are covered by a coating of resin to improve their mechanical strength. This paper describes methods for evaluating the degree of curing of optical fiber coating materials, and then introduces a method for evaluating the degree of resin curing using a rigid-body pendulum-type viscoelasticity testing apparatus.