Optical fibers have been extensively employed in a variety of fields. However, the need of high strength, excellent resistance to moisture permeation and tolerance to heat becomes apparent when such optical fibers are used in nuclear power plants and chemical plants in particular. Plastic coatings as conventional made of optical fibers cables would be replaced by the optical fiber coated with a layer of metal.

Several techniques have been applied to make a metal coating for the optical fibers. Dipping method, to pass optical fibers through a bath containing metal melt, was found the simplest. This dipping method, however, suffers from a disadvantage of a generation of a microbent due to the differences of the linear expansion between metal and the silica substrate [1]. Moreover, the control of the thickness was found difficult using the dipping method. Chemical vapor deposition was also used to form the metal coating on optical fibers.