A RESIN-FILLED OPTICAL MIXING ROD COUPLER.

This memorandum describes a technique for making optical mixing rod splitters and combiners using plastic materials to form a waveguide type mixing region. The mixing rod consists of a Teflon(R) FEP tube filled with a transparent, RTV resin. A bundle of end-cleaved plastic-clad silica fibers is placed in one end of the filled tube. A single large-core, plastic fiber is located at the opposite end. The liquid silicone RTV is injected into the tube such that it captures both the fiber bundle and the plastic fiber, holding them in place. This technique solves many of the problems encountered in making optical mixing rods including expensive fiber preparation and alignment. For the best device, a 1 x 9 splitter/combiner with diamond -cleaved fiber end faces, combiner and splitter efficiencies in the range of 60-70% were achieved.