The implementation of optical transmission systems requires connectors to couple the optical fibers together. In telecommunications applications, these connectors must be routinely coupled and uncoupled during installation, testing and maintenance. It is desirable, therefore, that the connectors be durable, relatively maintenance free and capable of low-loss interconnection after repeated use.
Molded optical fiber connectors, either directly molded onto the end of an optical fiber or subsequently affixed thereto, are particularly well-suited for telecommunications applications. One such optical connector, for example, is disclosed in U.S. Pat. No. 4,107,242 to P. K. Runge, issued Aug. 15, 1978 and in a related application to the same inventor, Ser. No. 630,930, filed Nov. 11, 1975, now abandoned, and assigned to the present assignee. The referenced connector utilizes two tapered plugs which are accurately aligned end to end in a sleeve. Precise molding and dimensional stability of the connector alignment surfaces are required to provide a 0.4 dB coupling loss over many years of service.
In an application to L. Curtis, Ser. No. 837,398, filed Sept. 28, 1977, now U.S. Pat. No. 4,173,389 Nov. 6, 1979, and assigned to the present assignee, a sleeve member is inserted in the mold to eliminate surface defects in the connector. The sleeve traps the gas bubbles formed during molding, thereby eliminating voids which would otherwise be formed. While this technique works satisfactorily, dimensional stability and precise symmetry of the alignment surfaces can still be a problem. In addition, the molding of a connector about an optical fiber produces bending of the fiber. Such bends cause attenuation of the optical signal and, if severe, fiber breakage.