Optical waveguides – With optical coupler
Reexamination Certificate
2002-06-04
2004-07-13
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With optical coupler
C385S089000, C385S024000, C385S088000, C398S150000
Reexamination Certificate
active
06763157
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention most generally relates to the alignment of planar arrays of electro-optical devices with optical link connectors used for multi-channel optical data communications; and more particularly to a method for mapping the results of the physical alignment of an optical array to a multi-channel optical link connector where multiple electro-optical devices are available for each optical channel to optimize an emitter/detector pair and provide redundancy.
2. Background Art
Integrated circuit technology allows large numbers of VCSEL (Vertical Cavity Surface Emitting Laser) laser emitter optical transmitters and p-i-n diode photo detector optical receivers to be constructed as large, two dimensional planar arrays, with one or more such arrays mounted on a common ASIC (Application Specific Integrated Circuit) substrate, as by flip-chip methods, also known as hybridization mounting techniques, each emitter and/or detector of the array making electrical connections with circuitry previously constructed in the ASIC substrate. This compound device, when coupled with precision alignment to a terminal end or node of a multi-channel optical link such as the end of a fiber optic bundle, provides an electro/optical communications interface where an electronic signal is converted by a VCSEL to an optical signal, directed at a end face of a single channel optical core of a terminator/connector, and hence along an optical transmission path fiber within the bundle, to be discharged via a carefully aligned receiving end fiber terminator/connector into a photo diode opto-electronic receiver on the same or another optical array of the same or another ASIC substrate, and converted by that photo detector back into an electronic signal. Fiberoptic communications channels provide significantly greater speed and effective bandwidth capabilities as compared to electrically conductive leads.
Each core end of the optical fiber bundle terminator or connector must be carefully aligned with its VCSEL on one end and corresponding detector on the end in order for the optical communications channel to be effective. Light pipes and image guides are commonly used to terminate a fiber bundle and connect the individual light fibers to their respective optical elements in planar photo arrays. These must be carefully aligned without actual contact and mechanically fastened to the planar array or its ASIC substrate so as to maintain optical alignment. Sufficient misalignment between the optical face of the array and the terminator face, in any of the Z-axis parameters of lateral offset, rotation, tilt, and spacing as between a multi-channel fiber terminator and a photo optic array, can cause a significant number of optical channels to be unusable.
As the density of the arrays of emitters and detectors increases, coupling a multi-channel fiber optic cable, image guide, or other optical connector or terminating device to the transceiver array becomes an increasingly more arduous task. Lateral offset and rotation alignment are particularly burdensome, while spacing and tilt alignment are more easily controlled with proper mechanical connectors and spacing structures.
What is needed is a device and system for self alignment of emitters and detectors that can determine the optimal emitter/detector pair as well as establish spare detectors and emitters that can be used when the primary emitter/detector pair degrades in performance. Such an invention should allow multiplexing of emitters operating at a single wavelength to be transmitted in a single fiber and be demultiplexed at the other end by the detectors. There can be a memory section that stores the insertion loss values of the mapping process to enable redundant emitters and detectors to quickly switch over form faulty emitters or detectors.
SUMMARY OF THE INVENTION
The invention is devised in the light of the problems of the prior art described herein. Accordingly it is a general object of the present invention to provide a novel and useful apparatus and technique that can solve the problems described herein.
It is an objective of the invention to provide a method for determining the alignment of a multi-channel optical link connector to a planar optical array.
It is another objective of the invention to provide a method for determining the alignment of each of the channels of a multi-channel optical link connector to the optical devices on a planar optical array.
It is a further objective to provide a method for determining the alignment of both ends of each of the channels of a multi-channel optical link to the optical devices of respective planar optical arrays.
An object of the invention is a self-aligning apparatus for electro-optical devices and optical connectors, comprising at least one planar array containing a plurality of optical detectors and a plurality of optical emitters with respective drive circuitry for said emitters and said detectors. There is at least one optical link connecting the emitters and the detectors of the planar array, wherein the optical link establishes an illumination area within the plurality of detectors. A processing section is coupled to the detectors and coupled to the emitters, wherein the processing section controls light signals from the emitters to the illumination area and wherein the processing section performs selective measurements of the light signals with the detectors, and wherein the processing section selects a primary emmiter/detector pair based on the measurements.
Another object is the self-aligning apparatus, wherein based on the measurements the plurality of optical detectors comprise one or more spare detectors that are switchably connectable, or one or more spare emitters that are switchably connectable.
An additional object is the self-aligning apparatus, further comprising a monitoring section coupled to the primary emitter/detector pair to monitor performance of the primary emmitter/detector pair. Based on said measurements, one or more spare emitter/detector pairs can be substituted for the primary emitter/detector pair.
And a further object is the self-aligning apparatus, wherein the optical links are optical couplers selected from the group comprising ordered fiber bundle, image guide, waveguide, pigtail and microlenses. In addition, the optical links can be transmissive mediums selected from the group comprising free space optics and guided wave optics.
In one embodiment of the self-aligning apparatus, the processing section cycles through the detectors one at a time with one or more emitters active to precisely locate the illumination area. The cycling establishes a mapping of the measured values. Therefore, the device can include a memory section, wherein a table of insertion loss values from the selective measurements are stored in the memory section.
An additional object is the self-aligning apparatus, wherein the emitters and the detectors are located on separate planar arrays. The emitters can be located on different planar arrays and can even be separated from each other, as the present system performs a multiplexing/demultiplexing function.
Yet a further object is the self-aligning apparatus, wherein the emitters function as detectors by changing a voltage polarity of the emitters.
It should be apparent to those skilled in the art that the optical detector is a device that converts energy of incident radiation into electrical energy. There are various types of such devices and the present invention is not limited to a specific device. Likewise, the emitter is a device that emits radiation when electrical energy is applied, and is not specific to any one device.
An optical communications device with built-in redundancy, comprising at least one array containing a plurality of optical detectors and at least one array containing a plurality of optical emitters with respective drive circuitry for the emitters and detectors, wherein a group of emitters form an emitter channel and a group of detectors form a detector channel and
Sundaram Mani
Williams Richard J.
Maine & Asmus
Palmer Phan T. H.
Teraconnect Inc.
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