An apparatus comprises a housing having a first melting temperature and a fiber bundle extending through the housing. The fiber bundle comprises a plurality of fibers having a second melting temperature. An end of each of the plurality of fibers extends past an edge of the housing. The apparatus further comprises a first seal between the plurality of fibers themselves and a second seal between the plurality of fibers and an inner surface of the housing. The seals each comprise a glass material having a third melting temperature lower than the first two melting temperatures. The second seal is configured to be formed as a result of the fiber bundle being inserted into the housing. The glass material coats a tip of each of the plurality of fibers and at least a portion of a side of each of the plurality of fibers near an end of the fiber bundle.