9 percent palladium ii chloride obtainable from sigma aldrich corporation of st louis mo as required the activated surface of an optical fiber may be deactivated after rinsing with de ionized water by dipping the fiber in a second stannous chloride bath stannous chloride deactivator solutions of various concentrations have been found effective including the same composition as the stannous chloride sensitizing solution the deactivation step according to the present invention facilitates selective masking of a portion of an activated fiber whereby subsequent electroless metal deposition takes place only over areas of the fiber surface that remain activated after treatment with tin ii solution use of tin ii deactivation produces a masked fiber by dipping an activated optical fiber in a solution of acidified stannous chloride for about 1 60 seconds preferably about 15 seconds metallized optical fiber tips according to the present invention were processed up to and including the tin ii masking treatment as described above the catalyzed and masked optical fibers were then immersed in nimuden sx electroless nickel plating bath available from uyemura international corp ontario canada for 2 minutes at 88 u00b0 c to provide a metallized fiber having a ni u2014 p layer of about 15 mm to 20 mm long and approximately 0 44 micron thick formed at a constant deposition rate of 0 22 micron of ni u2014 p per minute the plated fibers were.