Amorphous Carbon Coated Optical Fibers

Two long-term reliability issues for silica based optical waveguides used in adverse environments are strength degradations by static fatigue and optical loss increases due to hydrogen diffusion into the lightguide structure. Hermetic coatings can prevent the reaction of OH and H sub 2 with the optical fiber thus overcoming these long-term aging effects which can degrade fiber performance. Processing techniques for the in-line deposition of a hermetic coating will be discussed and fiber performance evaluated.