Optical waveguides – With optical coupler – Particular coupling structure
Reexamination Certificate
2003-07-25
2004-06-08
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With optical coupler
Particular coupling structure
C385S033000, C385S053000, C385S047000, C385S093000
Reexamination Certificate
active
06748144
ABSTRACT:
TECHNICAL FIELD
The present invention relates to optical structures. More specifically, the present invention relates to a system and method for coupling and redirecting optical energy between two optical waveguides oriented at a predetermined angle relative to each other, such as an angle having a magnitude of ninety degrees.
BACKGROUND OF THE INVENTION
Communication networks rely on optical networks to transmit complex communication data, such as voice and video traffic. This voice and video traffic propagated over the optical network usually takes the form of high frequency optical signals that have a relatively high bit rate.
To support these high frequency optical signals, optical networks typically comprise a large volume of fiber optic cables that extend over long distances. Because the fiber optic cables extend over long distances, these cables usually encounter obstacles or redirection that are common with any utility line. In other words, the fiber optic cables of optical networks can be routed under streets and highways with multiple twists, turns, and junctions. The fiber optic cables also can extend between buildings in above-ground supporting environments, such as between telephone poles that have several changes in direction.
In many of these routing situations, the fiber optic cables are directed at various angles relative to the origination or starting point of the fiber optic cable. To change direction or to connect a fiber optic cable to another fiber optic cable, an operation known as splicing can be performed to connect fiber optic cables together.
The splicing of fiber optic cables can be a tedious and time-consuming process. For example, splicing fiber optic cables is similar to handling cables with diameters that approach the diameter of a human hair. For a typical splice of a fiber optic cable, two separate fiber optic cables are cut. Next, their ends are polished and then their ends are compressed together.
While the ends are compressed together, it is necessary for the geometric center of these human hair-size cables to be properly aligned. If these human hair-like fiber optic cables are not properly aligned, substantial losses in optical power can occur at the splice. In other words, optical energy leaving one fiber optic cable is not completely transferred into the other fiber optic cable because of the misalignment of the fiber optic cables relative to each other.
After splicing, the junction or splice can be placed in one of several different types of protective enclosures to protect the splice from exposure to environmental effects. For example, the splice can be placed within a splice box, a conduit, or within a breakout panel. These protective enclosures can be placed in a manhole, in a pedestal, or in drop points adjacent to the subscribers of the optical network. Protecting splices with enclosures demonstrates that splicing of fiber optic cables can be a costly and time consuming process that does not guarantee optical coupling efficiency.
In addition to the problems associated with splicing, fiber optic cables cannot be bent at very large angles such as ninety degrees without suffering substantial optical power losses. To prevent such power losses, fiber optic cables are gradually routed around the obstacles at angles substantially less than ninety degrees. The gradual routing of fiber optic cables requires an even distribution of the weight for the additional cable needed to make this cable routing.
The gradual routing can also relieve the physical stresses within a fiber optic cable that are associated with the bending of the fiber optic cable at these gradual angles. Stress caused by the gradual routing of a fiber optic cable should be minimized in order to eliminate micro-bending. Micro-bending can cause greater losses at longer optical wavelengths, such as the optical wavelengths that support dense wavelength division multiplexing.
The gradual routing of fiber optic cables at angles substantially less than ninety degrees around objects is usually referred to as a wide bending radius technique. Another major drawback of larger bending techniques, in addition to the problems of stress and the amount of cable to perform the operation, is that such techniques require a substantial amount of space. To alleviate the problems of fiber optic cable splice connections and wide bending radius techniques, optical connectors have been proposed to couple one fiber optic cable oriented in a first direction and a second fiber optic cable oriented in a second direction. However, conventional optical connectors are usually permanent in nature, meaning that adjustments to the connector and any optics contained in the connector cannot be made during installation in the field. If there are any problems with the optics contained within the conventional optical connector, the connector usually must be discarded instead of repaired. Further, if any adjustments to the optics within the optical connector are necessary, such adjustments cannot be made in the field since the connectors are typically designed to permanently encase or house the optics contained therein.
Another drawback of conventional optical connectors is that very few of these conventional optical connectors can withstand the harsh operating environments of optical cables. For example, optical connectors can be exposed to high temperatures as well as fluids for certain applications. The optical connectors must be able to withstand harsh temperatures and to keep out any fluids that may come in contact with the fiber optic cables and the connector.
Accordingly, there is a need in the art for a system and method for coupling and redirecting optical energy between two optical waveguides oriented at a predetermined angle relative to each other. There is also a need in the art for a system and method for coupling and redirecting optical energy between two optical waveguides that permits adjustments to the optics housed in the optical coupler while in the field or operating environment. In other words, there is a need in the art for an optical coupler that has fielded adjustable optics to permit the adaptation of the optical coupler to various types and sizes of optical waveguides.
Further, there is also a need in the art for an optical coupler that is impervious to any liquids that are present in the operating environment of the optical couple and optical waveguides. There is also a need in the art for optical couplers that can withstand harsh operating environments where the optical coupler can be subjected to high temperatures.
A further need exists in the art for optical couplers that employ optical waveguide connectors that can comprise the size and dimensions of any one of industry standard connectors known in the art. There is also a need in the art for optical couplers that can meet or exceed industry standards for optical connectors.
Additionally, the need exists in the art for optical couplers that can maximize the optical energy transfer between two optical waveguides, while minimizing any back reflection or other optical return losses. There is also a need in the art for optical couplers that provide automatic core-to-core alignment of optical wave guides in free space. Further, there is also a need in the art for optical couplers that can provide a junction or connection point between different types of optical waveguides, such as single mode optical fibers, or optical waveguides, such as multi-mode optical fibers.
SUMMARY OF THE INVENTION
The present invention is generally drawn to a system and method for coupling and redirecting optical energy between two optical waveguides oriented at a predetermined angle relative to each other. More specifically, the present invention provides an optical waveguide coupler that can be adjusted in the field and which can couple and redirect optical energy from a first optical waveguide oriented in a first position into a second optical waveguide oriented in second position different from the fist position. That is, the optical waveguide coupler accordi
Cyber Operations, LLC
King & Spalding LLP
Palmer Phan T. H.
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