| 摘要 |
A fiber optic coupler is formed by inserting a plurality of optical fibers into the longitudinal bore of a glass tube so that at least a portion of each fiber extends from at least one end of the tube. The midregion of the tube is collapsed onto the fibers, uncollapsed bore portions remaining at the tube end regions. Each bore portion is connected to the tube end surface by a funnel that facilitates the fiber insertion step. The central portion of the midregion is stretched to reduce the diameter thereof. In a first embodiment, glue is applied to the funnel. Before the glue is cured, a sufficient period of time is allowed to elapse to permit said glue to flow by capillary action between the fibers and the adjacent portion of the wall of the bore portion. The glue flows at least 3 mm into the bore portion beyond the bottom of the funnel. The glue that flows by capillary action fails to completely surround the fibers with glue. The glue is then cured. In a second embodiment, a hollow filament is inserted into the uncollapsed bore portion and a vacuum is applied to the filament. Glue, which is applied to the funnel, is drawn into the uncollapsed bore portion due to the evacuated condition thereof, thus filling the uncollapsed bore portion to the desired level. <IMAGE> |
