Hermetic optical fiber seal

摘要

The invention relates to a hermetic optical fiber feedthrough or connector, and a method of hermetically sealing an optical fiber at low temperature. The method involves stripping a portion of the buffer layer of an optical fiber. The stripped portion of the fiber is inserted into a ferrule having a high coefficient of thermal expansion closely matching that of a low melt temperature solder. The ferrule is heated to melt the solder, the stripped portion of the fiber is then directly soldered into the ferrule. Upon cooling the solder and ferrule cool and shrink relatively uniformly thereby forming a compressive hermetic solder joint surrounding the stripped fiber. An epoxy may be inserted into an aperture formed in the ferrule. The epoxy forms a seal around the hermetic solder joint and bonds with the stripped fiber to improve the tolerance of the hermetic seal to mechanical deformation and increases the pull strength of the seal. Advantageously, the optical properties are not altered by the process.