Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
2001-06-28
2004-01-13
Nguyen, Khiem (Department: 2839)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
Reexamination Certificate
active
06676301
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an enhanced optical coupler, and in particular, to an enhanced optical coupler that is used to optically couple and align a light emitter or light detector with an optical fiber connector.
2. Background Information
Computer and communication systems are now being developed in which optical devices, such as optical fibers, are used as a conduit (also known as a wave guide) for modulated light waves to transmit information. These systems typically include a light emitter or a light detector optically connected to the optical fibers. A typical light emitter may be a so-called edge emitter, or a surface emitter, such as a vertical cavity surface emitting laser (VCSEL). A typical light detector may be a photodiode. A generic term of either a light emitter or a light detector is an “optoelectronic transducer.” The optical fibers, which collectively form a fiber-optic cable or ribbon, are typically coupled to the respective light detector and the light emitter, so that optical signals can be transmitted back and forth, for example.
As an example, optoelectronic transducers convert electrical signals to or from the optical signals; the optical signals carry data to a receiver (light detector) from a transmitter (light emitter) via the fiber-optic ribbon at very high speeds. Typically, the optical signals are converted into, or converted from, the associated electrical signals using known circuitry. Such optoelectronic transducers are often used in devices, such as computers, in which data must be transmitted at high rates of speed.
The conventional light emitter allows for integrated two-dimensional array configurations. For example, the active regions of a conventional VCSEL can be arranged in a linear array, for instance 12 active regions spaced about 250 microns apart, or in area arrays, for example, 16×16 arrays or 8×8 arrays. Of course, other arrangements of the arrays are also possible. Nevertheless, linear arrays are typically considered to be preferable for use with optoelectronic transducers, since it is generally considered easier to align the optical fibers that collect the light emitted from the VCSELs in a linear array, than in an area array. Moreover, it is also possible to utilize the active regions singly, i.e., without being arranged in an array.
The optoelectronic transducers are normally located on either input/output cards or port cards that are connected to an input/output card. Moreover, in a computer system, for example, the input/output card (with the optoelectronic transducer attached thereto) is typically connected to a circuit board, for example a mother board. The assembly may then be positioned within a chassis, which is a frame fixed within a computer housing. The chassis serves to hold the assembly within the computer housing.
Typically, each optical fiber of the ribbon is associated with a respective active region. Further, it is conventional for the ends of the optical fibers of the ribbon to terminate in a fiber connector. Such fiber connectors usually have an industry standard configuration, such as the MTP® fiber connectors manufactured by US Conec, Ltd. of Hickory, N.C. However, fiber connectors having the industry standard configuration are not suitable for connecting directly with the sensitive active regions of the typical light emitters or light detectors. Should direct contact occur between the respective active regions and the fiber connector, the fiber connector would likely damage the active regions, causing the light emitter or light detector to become inoperative. It is thus conventional to space the fiber connector away from the active regions. However, as will be appreciated, by providing a space, it thus becomes desirable to provide a way of optically coupling the active regions with the spaced apart fiber connector, so that the optical signals can be accurately and efficiently transmitted therebetween.
One conventional manner of optically coupling the active regions with the fiber connector is to provide a lens assembly in the space therebetween. However, lens assemblies tend to be complicated and expensive. Thus, it is also known to provide a fiber optic coupler between the active regions and the fiber connector. However, the conventional fiber optic coupler has a limited length, due to manufacturing constraints. Thus, the known fiber connectors must be positioned relatively close to the active regions, which may limit design options.
Moreover, it is important to ensure that most of the light emitted from the active regions of the light emitter reaches the respective optical fibers, and that most of the light emitted from the optical fibers reaches the respective active regions of the light detector. It is thus desirable to ensure that the fiber optic coupler is precisely aligned with the respective active regions and the fiber ends disposed within the fiber connector.
SUMMARY OF THE INVENTION
It is, therefore, a principal object of this invention to provide an enhanced optical coupler.
It is another object of the invention to provide an enhanced optical coupler that solves the above mentioned problems.
These and other objects of the present invention are accomplished by the enhanced optical coupler disclosed herein.
According to one aspect of the invention, the optical coupler includes at least two plates disposed in a superposed relationship. In the exemplary aspect of the invention, the plates are essentially rectangular. Although the plates can have other shapes without departing from the spirit and scope of the invention, it is currently believed to be preferable if at least a portion of two end faces, such as opposing end faces, of the plates have a flat, planar configuration. This configuration allows the respective end faces to be brought relatively close to the active regions and fiber connector. Further, the end faces can be arranged perpendicular to a primary surface of the plates, or arranged at an angle. Moreover, one end face can be arranged perpendicularly and the other end face can be angled, for example, the end face closest to the active regions. This angled configuration may help to prevent light from being reflected back to the active regions. Moreover, since the plates are to be superposed together, it is desirable if the abutting surfaces of the plates are flat and planar. Further, the plates can mirror one another in their configuration, or have an asymmetrical configuration. For example, one of the plates may have a notch or a radius formed in the end face to accommodate wiring or other components that may be connected to the light detector/light emitter, so as to not interfere with the placement of the optical coupler.
The plates may be formed from fused silica, ceramic, or a highly filled polymer (i.e., a polymer that has a filling, such as glass), for example. These materials can be readily etched for forming the features of the optical coupler, and allow optical fibers contained within the coupler (which are separate from the optical fibers of the ribbon) to be polished without damaging the end faces of the plates. Further, such materials have similar coefficients of thermal expansion to the optical fibers, so that the various components expand and contract together. In contrast, if the plates were formed of a conventional plastic material, the material would tend to melt and coat the end faces of the optical fibers during the polishing stage. Further, plastic plates would not expand and contract with the fibers.
Moreover, the plates are preferably joined together using an adhesive, such as an epoxy resin, for example. However, the plates may be joined together using other means without departing from the spirit of the invention.
In another aspect of the invention, at least one of the plates, and preferably both of the plates have grooves formed therein. When the plates are superposed and joined together, the respective grooves of one plate face the respective grooves of the other plate to form a plurality o
Chan Benson
Johnson Glen Walden
Kuczynski Joseph
Malagrino Jr. Gerald Daniel
Moon James Robert
Nguyen Khiem
Rabin & Berdo PC
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