Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
1999-10-20
2001-12-04
Schuberg, Darren (Department: 2872)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
C385S076000, C385S087000
Reexamination Certificate
active
06325549
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to connectors for interconnecting optical fibers to each other and to other optical components.
2. Description of the Related Art
Optical fiber communication systems are increasingly being used to transport data in the form of light pulses over long distances because they exhibit a very large capacity for carrying information, are light-weight, and are immune to electromagnetic interference. Important components of any optical fiber communication system are connectors for the optical fibers. These connectors may function as splices for connecting the ends of two optical fibers, or may be used to connect an optical fiber to other optical components.
It is important for the connector to properly align the optical fiber so that the insertion losses are minimized at the point at which the optical fiber is coupled to another optical fiber or to an optical component.
Optical fibers are usually formed of a thin glass or plastic fiber. Accordingly, the connector must also protect the end of the thin fiber from physical damage. In addition, the connector itself must not damage the end of the fiber during the connection or disconnection process.
Prior art connectors typically use a ferrule in which the end of an optical fiber is cemented in place to protect the end of the fiber from physical damage. The ferrule containing the end of the optical fiber is then aligned via insertion of the ferrule into a socket or plug. Because the end of the optical fiber is cemented in the ferrule, the fiber is held at an exact aligned location in the ferrule and the end of the fiber is physically protected.
A typical prior art connector device is disclosed in U.S. Pat. No. 5,768,455 (Konik). This prior art device includes a ferrule
12
for holding a length of bare fiber. The ferrule itself is held in a plug frame
13
(see FIG.
2
).
Another prior art connector is shown in U.S. Pat. No. 5,638,474 (Lampert et al.). This prior art connector also employs a ferrule
140
which is held within a base member
150
. The ferrule
140
receives the buffered fiber
33
which does not include the outer jacket
31
or strengthening members
32
that are placed over the buffered fiber.
More than one optical fiber may be inserted into a ferrule as shown in the prior art connector of U.S. Pat. No. 5,712,939 (Shahid) and U.S. Pat. No. 5,862,281 (Shahid), in which the fibers are held in place by a mold and the mold is filled with a material that encapsulates the fibers and forms a plug. The encapsulation of the end portions of the fibers is similar to the cementing of the above prior art devices in ferrules. Another prior art connector for holding multiple optical fibers is shown in U.S. Pat. No. 5,625,733 which has a cylindrical ferrule
100
,
101
(see FIGS.
1
and
2
); this particular connector is specifically designed for connecting optical fibers to optical devices.
The prior art connectors thus far described permanently connect the end of an optical fiber within a ferrule or plug. The Volition fiber optic cable systems manufactured by 3M, on the other hand, comprise plug and socket assemblies for connecting the ends of optical fibers. In the 3M systems the end of the optical fiber is free within the plug and is only held in the plug a preset distance from the end of the fiber. Within the socket, the free end of the plug-carried optical fiber is guided along a V-groove until it abuts the end of the socket-carried optical fiber. The plug and socket are designed so that there is a force urging the optical fibers into abutment when the plug is fully inserted into the socket. A specific type of glass optical fiber is used in this system. In addition, the Volition systems require the use of factory-assembled patch cords.
Accordingly, a significant problem and drawback of these prior art devices is that it is difficult, and in some cases impossible, to field mount the connectors to an optical fiber.
SUMMARY OF THE INVENTION
The present invention provides a connector for connecting an end of a first optical fiber to either another optical fiber or an optical device. The connector herein described is specifically designed for a plastic optical fiber (POF) having an outer diameter of 0.5 mm; however, the inventive connector can be used with any optical fiber that exhibits similar robustness. The connector includes a fiber holder portion, such as a sleeve, which receives the bare POF. The sleeve may also comprise a larger diameter portion which receives a fiber jacket. To terminate the POF, a portion of the fiber jacket is removed from the end of the POF to be terminated, and the bare end of the POF is inserted in the sleeve. A fiber clamp is then used to retain the optical fiber in the connector. The connector also includes a positioning guide comprising radial extending members which extend radially inward from a radially inner wall of the connector such that the radial inner ends of the positioning grips retain the optical fiber in a central position in the connector. The positioning guide may also extend at an angle to and toward the insertion direction. This configuration facilitates installation and provides enhanced prevention of unintended removal of the POF.
The connector may be designed so that the connector embodies a standard type of connector such as an LC-style connector or an RJ-45 connector or any other known or applicable form of connector.
The connector may additionally be configured with a half sleeve having a longitudinal V-groove so that two such connectors may be used to interconnect the ends of two POFs. In this embodiment, the connectors are arranged so that the V-groove of each opposes the other to retain the POFs in place.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
REFERENCES:
patent: 4838641 (1989-06-01), Morimoto et al.
patent: 5499310 (1996-03-01), Ueda
patent: 5712939 (1998-01-01), Shahid
patent: 0 177 937 (1986-04-01), None
patent: 0 517 346 (1992-12-01), None
patent: 0 869 378 (1997-02-01), None
Lucent Technologies Inc
Schuberg Darren
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