Optical-fiber feedthrough in pressure housing

The structure for introducing fibers into the pressure housing of a submarine optical repeater is studied. As a result of investigations into sealing materials, fiber strength, and optical characteristics, the following structure is adopted. Fibers, whose primary coat is metal instead of silicone, are fixed by epoxy resin to withstand water pressure, and the outside surface of the resin is covered with solder to keep the resin free from water vapor. Experimental results show that this structure meets the requirements.