Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
1998-12-31
2001-10-23
Font, Frank G. (Department: 2877)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
Reexamination Certificate
active
06305850
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to multifiber connectors and, more particularly, to the alignment and insertion of a plurality of optical fibers into a multifiber ferrule.
BACKGROUND OF THE INVENTION
Multifiber cables are being increasingly employed in a wide variety of applications. As such, multifiber connectors must frequently be mounted upon the end portion of a multifiber cable in order to facilitate connection of the cable with another multifiber cable or with any of a variety of optical devices. Typically, the multifiber cables are ribbonized such that the plurality of optical fibers are maintained in a side-by-side relationship by a matrix material.
Multifiber connectors generally include a multifiber ferrule, such as a DC ferrule or an MT ferrule, that define a relatively large opening proximate the rear end of the ferrule for receiving the multifiber ribbon. Conventional multifiber ferrules also define a plurality of bores or microholes proximate the forward end of the ferrule for receiving individual ones of the optical fibers of the multifiber ribbon. In order to feed or guide the optical fibers into the respective bores, the lateral cross-sectional size of the opening proximate the rear end of the ferrule is typically reduced as the opening advances from the rear end of the ferrule into medial portions of the ferrule. As such, the opening serves to guide a multifiber ribbon through the ferrule and into general alignment with the plurality of bores defined by the forward end of the ferrule. While the opening is effective for guiding a multifiber ribbon, the opening does not provide much, if any, guidance for individual ones of the optical fibers.
Typically, the spacing between the bores defined by a multifiber ferrule and the spacing between the optical fibers of a multifiber ribbon are approximately equal. As such, even though the matrix material has been stripped from the end portions of the optical fibers prior to inserting the multifiber ribbon into the opening defined by the rear portion of the ferrule, the multifiber ribbon will maintain the spacing of the end portions of the optical fibers. Thus, the end portions of the optical fibers of the multifiber ribbon can be inserted into respective bores defined by the ferrule once the multifiber ribbon has been guided into general alignment with the plurality of bores by the opening defined by the rear portion of the ferrule.
Multifiber connectors can also include a lead-in tube to guide the multifiber ribbon into the opening defined by the rear portion of the ferrule. Typically, the lead-in tube is a cylindrical tube that serves to guide the multifiber ribbon as a whole and not individual ones of the optical fibers. As such, a conventional lead-in tube guides the multifiber ribbon into the opening defined by the rear portion of the multifiber ferrule, but does not further guide the optical fibers through the ferrule and into the respective bores defined by the forward portion of the ferrule.
While conventional multifiber ferrules and their associated lead-in tubes provide sufficient guidance for the optical fibers of a multifiber ribbon due to the correspondence between the spacing of the optical fibers of a multifiber ribbon and the spacing of the openings defined by the forward portion of the ferrule, problems arise in instances in which a multifiber ferrule is to be mounted upon the end portions of a plurality of loose optical fibers, i.e., a plurality of nonribbonized optical fibers. In this instance, a technician could attempt to individually insert the end portion of each optical fiber through the opening defined by the rear portion of the multifiber ferrule and into the respective bore defined by the forward portion of the multifiber ferrule. As will be apparent, the extremely small size of the multifiber ferrule and the optical fibers would make this insertion process extremely tedious and quite time consuming. In addition, attempts to insert an individual optical fiber into a respective bore defined by the forward portion of a ferrule may fail to appropriately align the end portion of the optical fiber with the respective bore such that the end portion of the optical fiber would be stubbed into ferrule, thereby possibly damaging the optical fiber.
Accordingly, a technician generally forms the plurality of loose optical fibers into a ribbon format in order to mount a multifiber ferrule upon the end portions of a plurality of loose optical fibers. For example, end portions of the plurality of optical fibers can be inserted into a fixture that establishes a desired spacing between the optical fibers. A tape, such as a KAPTON™ tape, can then be wrapped about the plurality of optical fibers in order to secure the end portions of the optical fibers in a ribbonized format having the desired spacing. Thereafter, a multifiber ferrule can be mounted on the end portions of the plurality of optical fibers that have been bound together by tape. While this ribbonization of a plurality of otherwise loose optical fibers facilitates the mounting of a multifiber ferrule upon the end portions of the optical fibers, the ribbonization of the plurality of loose optical fibers is somewhat time consuming. In addition, this technique for ribbonizing a plurality of loose optical fibers generally requires a specialized fixture for receiving the end portions of the optical fibers and for establishing the spacing therebetween. While techniques have therefore been developed to mount multifiber ferrules upon the end portions of a plurality of loose optical fibers, a need still exists for improved techniques for mounting multifiber ferrules upon the end portions of a plurality of loose optical fibers in a rapid manner without damaging the optical fibers.
SUMMARY OF THE INVENTION
A multifiber connector subassembly is therefore provided that includes a ferrule and a multifiber alignment adapter for individually guiding the plurality of individual optical fibers into alignment with respective ones of the bores or microholes defined by the ferrule. In this regard, the ferrule includes a forward portion that defines the plurality of bores for receiving respective end portions of a plurality of optical fibers. The ferrule also generally includes a rear portion defining an opening of a predetermined shape. According to the present invention, the multifiber alignment adapter defines a plurality of lengthwise extending passageways for receiving respective ones of the plurality of optical fibers. The multifiber alignment adapter also has a forward end having an exterior shape that corresponds to the predetermined shape of the opening defined by the rear portion of the ferrule. As such, the forward end of the multifiber alignment adapter can be positioned within the opening defined by the rear portion of the ferrule such that each passageway defined by the multifiber alignment adapter is aligned with a respective bore defined by the ferrule. Accordingly, the multifiber connector subassembly of the present invention can guide each individual optical fiber through a passageway and into the respective bore defined by the ferrule without being stubbed or otherwise damaged.
Each bore defined by the ferrule has a lengthwise extending axis. Likewise, each passageway defined by the multifiber alignment adapter has a lengthwise extending axis. Accordingly, the forward end of the multifiber alignment adapter is preferably positioned within the opening defined by the rear portion of the ferrule such that the lengthwise extending axis of each passageway of the multifiber alignment adapter extends collinearly with the lengthwise extending axis of the respective bore defined by the ferrule.
The multifiber alignment adapter of the present invention includes an adapter body extending lengthwise between opposed forward and rear ends. The adapter body defines the plurality of passageways which, in one advantageous embodiment, are a plurality of lengthwise extending grooves. While the adapter body need only define grooves along a port
Luther James P.
Wagner Karl M.
Corning Cable Systems LLC
Font Frank G.
Stafira Michael P.
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