Optical waveguides – With disengagable mechanical connector
Reexamination Certificate
1999-11-10
2002-04-09
Healy, Brian (Department: 2874)
Optical waveguides
With disengagable mechanical connector
C385S055000, C385S076000, C385S077000, C385S078000
Reexamination Certificate
active
06367984
ABSTRACT:
FIELD OF THE INVENTION
The invention relates in general to optical fiber adapters used to couple the connector of a first optical fiber cable to the connector of a second optical fiber cable. More particularly, the invention relates to an improved optical fiber adapter constructed as a one-piece tubular body with an alignment sleeve holder for capturing an alignment sleeve used to couple the ferrules of the two optical fiber connectors having the same diameter ferrules together, or alternatively provided with a stepped alignment sleeve for coupling optical fiber connectors having dissimilarly sized ferrules together.
BACKGROUND OF THE INVENTION
The use and construction of optical fiber cables, and of optical fiber adapters, also referred to as couplers and more recently as build-outs, used for coupling optical fiber cables together is well known. Optical fiber cables are provided with optical fiber connectors at their ends, the connectors being one of the several known types of connectors, namely being either an SC, an ST®, an FC, or an LC type of optical fiber connector. As is known, the SC, ST®, and FC connectors are each provided with a 2.5 millimeter diameter ferrule which houses the optical fiber therein along a longitudinal axis of the connector, whereas the LC type of optical fiber connector is provided with a smaller 1.25 millimeter diameter ferrule.
The earliest types of optical fiber adapters were made using a simple coupler formed as a tubular body sized and shaped to allow an alignment sleeve to be passed therethrough, and in which the ferrules of the respective optical fiber connectors were placed so that the ferrules abutted one another within the alignment sleeve for the purpose of transmitting an optical signal from one optical fiber cable to the other. An example of such an early type of optical fiber coupling is disclosed in U.S. Pat. No. 5,082,345 to Cammons, et al., assigned to AT&T Bell Laboratories, a predecessor in interest to the assignee of this invention. The coupler of Cammons, et al. was adapted to couple two of the same type of optical fiber connectors together, but first required that the ferrule of a first one of the two connectors be passed into one of the ends of the alignment sleeve and then passing both the alignment sleeve and the ferrule together into the body of the adapter, whereupon the second ferrule was passed into the alignment sleeve. The device of Cammons was not provided with a means for separately securing the alignment sleeve within the body of the adapter, rather the ferrule of the first optical fiber connector was used for this purpose. Should the alignment sleeve of the “345 patent have been placed in the adapter prior to one of the ferrules being passed therein, the first ferrule inserted into the adapter would have pushed the alignment sleeve out of the adapter, making the coupling of two optical fiber connectors quite difficult to accomplish in the field.
Another example of an early optical fiber adapter is disclosed in U.S. Pat. No. 5,212,752 to Stephenson, et al., also assigned to AT&T Bell Laboratories. The '752 patent discloses a one-piece coupler used for coupling the ends of two optical fiber cables having an SC connector at their respective ends together. As with the patent to Cammons, et al., the '752 patent was designed for use only with identically sized and shaped optical fiber connectors, in this instance SC connectors.
Accordingly, and as these two patents demonstrate, the problem that developed with these early optical fiber couplers was that as the number of differing types of optical fiber connectors increased, for example the SC, ST®, FC, and LC family of optical fiber connectors now being widely used, the situation frequently arose in the field in which a first optical fiber cable having a first type of optical fiber connector was to be connected to a second optical fiber cable having a second type of optical fiber connector.
An early solution to the problem of coupling differing types of optical fibers together was addressed in U.S. Pat. No. 5,067,783 to Lampert, also assigned to AT&T Bell Laboratories. The '783 patent to Lampert discloses an optical fiber connector build-out system having a first piece and a separate second piece which together formed the optical fiber adapter or build-out, and allowed an FC to ST® optical fiber connection, as well as ST® to ST®, and FC to FC optical fiber connections. Although Lampert represented an advance in the art, the problem still persisted that as newer types of optical fiber connectors were developed, namely the LC and SC family of optical fiber connectors, there remained a continuing need to provide a universal system of coupling different types of optical fiber connectors together.
The universal optical fiber build-out system of U.S. Pat. No. 5,274,729 to King, et al. was developed to solve the ongoing problem of coupling the myriad of differing types of optical fiber connectors together, which patent is also assigned to AT&T Bell Laboratories. The '729 patent to King, et al. allowed for the connection of SC, ST®, and FC connectors to one another, as desired. More recently, in a patent application entitled “Universal Modular Optical Fiber Build-Out”, filed in the U.S. Patent Office on Apr. 1
st,
1999, U.S. patent application No. 09/282,926, and assigned to Lucent Technologies, Inc., the successor in interest to AT&T Bell Laboratories, a system was developed for coupling not only the larger 2.5 millimeter diameter ferrules of the SC, ST®, and FC connectors to one another, but also allowing, for the first time, the smaller 1.25 millimeter diameter ferrules of the LC connectors to be quickly and easily coupled to optical fiber cables terminated with any one of the 2.5 millimeter diameter ferrules of the SC, ST®, and FC connectors.
A problem that has arisen with the systems of Lampert, King, et al. and the aforementioned U.S. patent application is that in order to couple differing types of optical fiber connectors together, the optical fiber build-outs, or adapters, have been constructed of a first half for the first optical fiber connector, and of a separate second half for the second, potentially differing, type of optical fiber connector in order to allow for these couplings. This requires that two pieces be used to construct one optical fiber adapter, which construction is more costly in that it requires a larger parts inventory to accommodate “straight” and “hybrid” couplings, and may also lead to an increase in labor costs needed to assemble these optical fiber build-outs/adapters in the field. In essence, a pair of connectors is required, which connectors must themselves first be connected to one another, in order to construct the adapter used to couple the two optical fiber cables together. Moreover, the fact that the two halves of the build-out are joined together to construct the build-out presents a potential point of structural weakness within the adapter.
What is needed, therefore, is a simple one-piece optical fiber adapter of a more robust design, one which is more rigid and thus more durable, and yet which is made of the same low-cost and high durability plastic materials of the aforementioned and more recent optical fiber build-out systems, the use of which will hopefully lead to lower inventory costs, lower manufacturing costs, and also require less labor in the field by eliminating the step of first constructing the adapter prior to connecting the ends of optical fiber cables/connectors together, and which will also fit into the same footprint, i.e. panel opening, formed in the mounting panels of the junction boxes and/or switch stations at which these panels are found, and at which the optical fiber cables are terminated and/or coupled together. Moreover, there is a need for such an improved one-piece tubular optical fiber adapter which can be used for coupling any one of the known types of optical fiber connectors to any other one of the known types of optical fiber connectors, be it an LC, SC, ST®, and/or FC size and sty
Sheldon Steven E.
Stephenson Daniel L.
Fails, Esq. Charles H.
Healy Brian
Lucent Technologies - Inc.
Needle & Rosenberg P.C.
Pak Sung
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