Artikel omfattende en sjælden jordarts- eller overgangsmetaldoteret optisk fiber

• Main Authors: JIN, SUNGHO, LEMAIRE, PAUL JOSEPH, WALKER, KENNETH LEE
• Format: Patent
• Language: Danish
• Published: 01.12.1997
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; DEVICES USING STIMULATED EMISSION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES; METALLURGY; MINERAL OR SLAG WOOL; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS; TRANSMISSION

We have discovered that silica-based optical fibers (e.g., 33) that are doped with Ge, Al and a rare earth (e.g., Er) can be very susceptible to hydrogen-induced attenuation change. For instance, such fiber can exhibit loss increase rates that are, at 20 DEG C, 10 times larger than those of a standard single mode fiber. We also believe that transition metal-doped silica-based fibers can exhibit large hydrogen-induced attenuation change. In many circumstances (e.g., amplifier fiber, attenuator fiber) significant attenuation change of optical fiber is undesirable. We disclose that such change can be substantially eliminated by provision of hydrogen gettering material and/or a "hermetic" fiber coating. It is currently preferred to provide silica cladding material that is a hydrogen getter, and also provide a "hermetic" fiber coating. Containment of the fiber, together with a quantity of a gettering material (e.g., ErFe2) in an essentially hermetic enclosure is also disclosed.