Optical fibers with a light absorbing coating

摘要

Optical fibers having one or more polymeric coatings have been found to be sensitive to extraneous light arising either as incident light from outside the optical fiber or as light escaping the fiber at bends and being reflected back into the fiber by a coating acting as a secondary cladding. In either case the extraneous light intensity may be reduced by placing at least one light absorbing component in a coating. Where the light absorbing component is placed in a coating between the primary cladding of the optical fiber and the secondary cladding both sources of extraneous light may be reduced or eliminated. Particulate amorphous carbon is an effective light absorber because of the broad range of optical wavelengths absorbed and because of its efficiency of absorption (high extinction coefficient) over this range.