Optical waveguides – With optical coupler – Switch
Reexamination Certificate
2000-07-07
2002-07-02
Lee, John D. (Department: 2874)
Optical waveguides
With optical coupler
Switch
C385S018000, C385S023000, C359S813000, C359S814000
Reexamination Certificate
active
06415068
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This present invention relates to a microlens switching assembly and optical switching using a microlens switching assembly.
2. Background of the Invention
Optical switches are becoming important components in fiber-optic communication networks for fast switching. In particular, advancements in the optical application of microelectromechanical systems (MEMS) has made fiber communication networks one of the most promising markets for optical microelectromechanical systems. Micro-optomechanical switches offer a cost-effective method for improving reliability and flexibility of communication networks.
There are two major types of micro-optomechanical switches currently known. One involves movable optical fibers or optical waveguides. The second involves movable micromirrors inserted in the light path in free space. A light beam traveling the light path between optical fibers or waveguides is reflected by a micromirror along a different light path so that the beam may be coupled to a desired output optical fiber or waveguide. Micromirror switches provide distinct advantages over switches that move the optical fibers or waveguides themselves. In particular, the size of the switch is very small because the beam can be reflected at an arbitrary angle. Multiple switching is also possible in a single device because the light beams will not interfere with each other in free space. Also, only a small driving force is required to move the micromirrors, much less than that needed to move optical fibers and waveguides.
Further development of micromirror switches has been directed to reducing the insertion loss due to coupling loss across the free space and reflection loss at the micromirror. The coupling loss may be decreased by having a small distance between the ends of the fibers or waveguides, by collimating the light beam, and by accurate alignment. The reflection loss may be decreased by smoother mirror surfaces and by mirror surfaces covered by high reflectance metals.
SUMMARY OF THE INVENTION
This invention provides systems and methods that use a microlens to selectively direct a signal from a source to a receiver.
This invention separately provides systems and methods that use a microlens to attenuate a signal received by a receiver from a source by directing the signal at least partially away from the receiver.
This invention separately provides systems and methods that use a microlens to selectively direct a signal from a source to one or more receivers of an array of receivers to switch the signal between the receivers of the array.
This invention separately provides systems and methods that use a microlens to selectively direct a signal from an input optical fiber to an output optical fiber.
This invention separately provides systems and methods that use a microlens to attenuate a signal received by an output optical fiber from an input optical fiber by directing the signal at least partially away from the output optical fiber.
This invention separately provides systems and methods that use a microlens to selectively direct a signal from an input optical fiber to one or more output optical fibers of an array of output optical fibers to switch the signal between the output optical fibers of the array.
This invention separately provides systems and methods that use a microlens to selectively direct laser light from a laser light source to a photodetector.
This invention separately provides systems and methods that use a microlens to selectively direct laser light from a laser light source to one or more photodetectors of an array of photodetectors to switch between the photodetectors of the array.
In various exemplary embodiments of the systems and methods of this invention, a microelectromechanical system (MEMS) drives a microlens between various positions. The microelectromechanical system may be comb-drive actuated and may include an elastically suspended support member that carries the microlens. The driver, the support member and the elastic suspension structure each may be made using a semiconductor material.
The microelectromechanical system-based comb-drive actuated microlens switching assembly according to this invention provides fast switching of signals. In various exemplary embodiments, the microlens switching assembly offers one or more advantages of small size, multiple switching and/or small required driving force. Further, in various exemplary embodiments, the microlens does not require any additional collimation device to reduce coupling loss. Additionally, in various exemplary embodiments, the microlens switching assembly involves only linear movement of the microlens, thus reducing complexity and increasing accuracy and reliability.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of various exemplary embodiments of the systems and methods according to this invention.
REFERENCES:
patent: 5025346 (1991-06-01), Tang et al.
patent: 5734490 (1998-03-01), Rabarot et al.
patent: 5861992 (1999-01-01), Gelbart
patent: 5923480 (1999-07-01), Labeye
patent: 6091537 (2000-07-01), Sun et al.
patent: 6229640 (2001-05-01), Zhang
patent: 6295171 (2001-09-01), Chao et al.
Publications “Micromachined Optical Switches for Free-Space Bean Steering” by Hiroyuki Fujita, et al., pp. 19-20, “MEM Mirrors Application in Optical Cross-Connects” by Herzel Laor pp. 21-22 and “Micromechanical Fiber Optic Switches Based on Electromagnetic Torsion Mirrors” by H. Toshiyoshi, et al., pp. 23-24, all of the IEEE/LEOS Summer Topical Meeting in Monterey, CA, ISSN: 1099-4742, Jul. 1998.
Scanning Microlens Shuttles Fabricated Using Silicon-On-Insulator Wafers,Decai Sun, Chingwen Yeh and Michel Rosa, Xerox Palo Alto Research Center (No date).
Doan Jennifer
Lee John D.
Oliff & Berridg,e PLC
Xerox Corporation
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