Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
2001-08-20
2004-01-06
Moskowitz, Nelson (Department: 3663)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S337100, C359S341410
Reexamination Certificate
active
06674559
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to optical information processing, and more particularly to optical automatic gain control using stable, non-absorbing optical hard limiters.
BACKGROUND OF THE INVENTION
In today's information age, optical communication technologies are being used more and more frequently for transmitting information at very high speeds. Traditionally, information processing equipment (such as switches, routers, and computers) process information electronically. Therefore, optical communications are often converted into electronic form for processing by the information processing equipment. This electronic processing is slow relative to the speed of the optical communications themselves, and thus often becomes a “bottleneck” of optical communication and processing systems.
A communication channel can be used more efficiently to transmit information if an encoding scheme is used to assign binary values to discrete intensity levels. This is difficult in an optical communication system due to the difficulty in controlling the intensity of the signal due to attenuation in the optical fiber. Therefore, it is difficult to establish a reference intensity level for optical communications over the optical fiber.
Automatic gain control can be used to normalize packets of varying intensities. Automatic gain control for optical communications is often accomplished by detecting the optical signal, transforming the optical signal in an electronic signal, processing the signal electronically, converting the processed electronic signal back into an optical form, and retransmitting the converted optical signal. Unfortunately, this process is limited by the speed of the electronics.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, optical automatic gain control (AGC) is accomplished using stable, non-absorbing optical hard limiters and various optical logic gates derived therefrom. The AGC mechanism preserves the ratios between signal levels and provides an adjustable amount of gain.
An optical automatic gain controller typically includes a number of AGC stages, where, in each AGC stage, a threshold input signal derived from an optical input signal is compared against a predetermined threshold for the AGC stage, and a gain input signal also derived from the optical input signal is amplified if and only if the threshold input signal is below the predetermined threshold. The threshold is reduced in each successive AGC stage.
REFERENCES:
patent: 4128300 (1978-12-01), Stotts et al.
patent: 4262992 (1981-04-01), Berthold, III
patent: 4573767 (1986-03-01), Jewell
patent: 4764889 (1988-08-01), Hinton et al.
patent: 4864536 (1989-09-01), Lindmayer
patent: 4894818 (1990-01-01), Fujioka et al.
patent: 4930873 (1990-06-01), Hunter
patent: 4932739 (1990-06-01), Islam
patent: 4962987 (1990-10-01), Doran
patent: 4992654 (1991-02-01), Crossland et al.
patent: 5078464 (1992-01-01), Islam
patent: 5144375 (1992-09-01), Gabriel et al.
patent: 5315422 (1994-05-01), Utaka et al.
patent: 5349593 (1994-09-01), Lomashevitch et al.
patent: 5461507 (1995-10-01), Westland et al.
patent: 5479384 (1995-12-01), Toth et al.
patent: 5488501 (1996-01-01), Barnsley
patent: 5537243 (1996-07-01), Fatehi et al.
patent: 5617232 (1997-04-01), Takemori
patent: 5623366 (1997-04-01), Hait
patent: 5655039 (1997-08-01), Evans
patent: 5706118 (1998-01-01), Takano
patent: 5739933 (1998-04-01), Dembeck et al.
patent: 5831731 (1998-11-01), Hall et al.
patent: 5999283 (1999-12-01), Roberts et al.
patent: 5999284 (1999-12-01), Roberts
patent: 6005791 (1999-12-01), Gudesen et al.
patent: 6041126 (2000-03-01), Terai et al.
patent: 6044341 (2000-03-01), Takahashi
patent: 6456221 (2002-09-01), Low et al.
patent: 6512416 (2003-01-01), Burns et al.
patent: 2002/0061738 (2002-05-01), Simmons et al.
“Wave proagation in nonlinear photonic band-gap materials” Li, et. al., Physical Review B: Condensed Matter vol. 53, No. 23, 15577-15585 (Jun. 15, 1996).
“The Interaction of Electromagnetic Radiation with Magnetic Media” http://www.qub.ac.uk/mp/con/magnetics_group/magnetoptics.html.
“Three-Dimensional Arrays in Polymer Nanocomposites” Kumacheva, et al., Advanced Material, 1999, 11, No. 3.
“Intergrable, Low-Cost, All-Optical WDM Signal Processing: Narrowband Hard Limiters and Analog-to-Digital Converters” Sargent, et al., Jan. 2000.
“Nonlinear Distributed Feedback Structures for Optical Sensor Protection” Brzozowski, et al., Apr. 2000.
“Optical Signal Processing Using Nonlinear Distributed Feedback Structures” Brzozowski, et al., IEEE Journal of Quantum Electronics, vol. 36, No. 5, May 2000.
“All-Optical Analog-to-Digital Converter for Photonic Networks Using Multilevel Signaling” Brzozowski, et al., Jun. 2000.
“Photonic Crystals for Intergrated Optical Computing” Brzozowski, et al., Jun. 2000.
“Nonlinear distributed-feedback structures as passive optical limiters” Brzozowski, et al., J. Opt. Soc. Am B, vol. 17, No. 8, Aug. 2000.
“Stability of Periodic Nonlinear Optical Structures for Limiting and Logic”, Brzozowski, et al., Sep. 2000.
“Transmission Regimes of Periodic Nonlinear Optical Structures” Pelinovsky, Dmitry, Rapid Communications, Physical Review E, vol. 62, No. 4, Oct. 2000.
“Nonlinear Disordered Media for Broad-Band Optical Limiting” Brzozowski, et al., IEEE Journal of Quantum Electronics, vol. 36, No. 11, Nov. 2000.
“Realization of All-Optical Ultrafast Logic Gates Using Triple Core Asymmetric Nonlinear Directional Coupler”, Natasa Trivunac-Vukovic, Journal of Optical Communications, 2001.
“All-Optical Analog-to Digital Converters, Hardlimiters, and Logic Gates”, Brzozowski, et al., Journal of Lightwave Technology, vol. 19, No. 1, Jan. 2001.
“Stable All-Optical Limiting in Nonlinear Periodic Structures”, Pelinovsky, et al., Feb. 8, 2001.
“All-Optical Signal Processing and Packet Forwarding Using Nonmonotonic Intensity Transfer Characteristics”, Johnson, E.V., A thesis submitted in conformity with the requirements for the degree of Master of Applied Science Graduate Department of electrical and Computer Engineering Univeristy of Toronto, 2001.
Johnson Erik V.
Sargent Edward H.
Moskowitz Nelson
Nortel Networks Limited
Steubing McGuinness & Manaras LLP
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