ELECTROLESS METALLIZATION OF OPTICAL FIBER FOR HERMETIC PACKAGING

摘要

An electroless process has been developed to deposit nickel and goldonto optical fibers using aqueous chemistry. The key to the process is a sensitizationof a surface of an optical fiber using a dilute aqueous stannous fluoride solution inabsence of oxygen. Stannous fluoride solution is prepared by dissolving crystallineSnF2 in deionized water. Subsequent treatment includes immersion of sensitizedoptical fiber in a palladium chloride/HCI aqueous solution and commerciallyavailable electroless nickel and electroless gold solutions. The process is compatiblewith either chemical or fusion lensing operations by using a strippable polymercoating to selectively metallize near the fiber end. The solder joints to the metallizedfiber are hermetic as determined by helium leak testing and solder pull-test strengthstypically range from 3-5 pounds, depending on the type of solder. This electrolessplating process for metallizing optical fibers makes feasible the incorporation ofsoldered fiber into packages which might be otherwise prohibitively expensive ormechanically infeasible with the sputtered metallization. The process is useful forall lightwave components which require either hermeticity or high reliability opticalfiber attachment.