Stephen E Alexander

US Patent:

6344915, Feb 5, 2002

Filed:

Jun 19, 1998

Appl. No.:

09/152892

Inventors:

Stephen B. Alexander - Millersville MD
Cecil D. Smith - Annapolis MD
Roy C. Litz - Freeland MD
Robert M. Corwin - Finksburg MD
Donald T. Newman - Severna Park MD

Assignee:

Ciena Corporation - Linthicum MD

International Classification:

H04B 1016

US Classification:

359177, 359179, 359134, 3593412, 35934144

Abstract:

The present invention provides a system and method for intelligently shutting down an optical energy source in a communication system having optical amplifiers upon detection of a system failure.

US Patent:

6404948, Jun 11, 2002

Filed:

Jan 26, 2001

Appl. No.:

09/770367

Inventors:

Stephen B. Alexander - Millersville MD
Jean-Luc Archambault - Severna Park MD
Victor Mizrahi - Columbia MD
Henry H. Yaffe - Reisterstown MD

Assignee:

Ciena Corporation - Linthicum MD

International Classification:

G02B 628

US Classification:

385 24, 385 15, 385 31, 385 37, 385 42, 359115, 359124, 359130

Abstract:

In accordance with the present invention, optical channels to be demultiplexed are supplied to first and second optical fibers via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups of channels. Each group of channels is next demultiplexed with sub-demultiplexers into individual channels, each of which is then sensed with a corresponding photodetector. Although the optical splitter introduces an optical power loss at the input to the demultiplexer, the interference filters and sub-demultiplexers create little additional loss. As a result, the total power loss associated with the present invention is significantly less than that obtained with a conventional n channel demultiplexer based on a 1Ãn splitter. Accordingly, large numbers of channels, e. g. , in excess of forty can be readily demultiplexed and detected.

US Patent:

6618176, Sep 9, 2003

Filed:

Feb 26, 2001

Appl. No.:

09/793645

Inventors:

Stephen B. Alexander - Millersville MD
Steve W. Chaddick - Annapolis MD
Roy C. Litz - Freeland MD
Cecil D. Smith - Severna Park MD

Assignee:

Ciena Corporation - Linthicum MD

International Classification:

H04J 1402

US Classification:

359133, 359110, 359124

Abstract:

The present invention provides a remodulating channel selector for a wavelength division multiplexed optical communication system. The remodulating selector receives a WDM input signal, selects a particular optical channel from the WDM signal and places the information from the selected signal onto a newly-generated optical output signal. The wavelength of the output optical signal can be the same as or different from one of the optical channels which comprises the WDM input signal. When used in a WDM optical communication system with remodulators at the transmission input, the remodulating selectors provide complete control over the interfaces with optical transmitters and receivers, permitting use with a broad range of optical equipment.

US Patent:

7369780, May 6, 2008

Filed:

Jul 15, 2003

Appl. No.:

10/618684

Inventors:

Stephen B. Alexander - Millersville MD, US
Steve W. Chaddick - Annapolis MD, US
Roy C. Litz - Freeland MD, US
Cecil D. Smith - Severna Park MD, US

Assignee:

Ciena Corporation - Linthicum MD

International Classification:

H04B 10/04
H04B 10/12

US Classification:

398183, 398185, 398186

Abstract:

The present invention provides a remodulating channel selector for a wavelength division multiplexed optical communication system. The remodulating selector receives a WDM input signal, selects a particular optical channel from the WDM signal and places the information from the selected signal onto a newly-generated optical output signal. The wavelength of the output optical signal can be the same as or different from one of the optical channels which comprises the WDM input signal. When used in a WDM optical communication system with remodulators at the transmission input, the remodulating selectors provide complete control over the interfaces with optical transmitters and receivers, permitting use with a broad range of optical equipment.

US Patent:

7809270, Oct 5, 2010

Filed:

Apr 8, 2008

Appl. No.:

12/099479

Inventors:

Stephen B. Alexander - Millersville MD, US
Steve W. Chaddick - Annapolis MD, US
Roy C. Litz - Freeland MD, US
Cecil D. Smith - Severna Park MD, US

Assignee:

Ciena Corporation - Linthicum MD

International Classification:

H04J 14/02
H04B 10/04

US Classification:

398 79, 398183

Abstract:

The present invention provides a remodulating channel selector for a wavelength division multiplexed optical communication system. The remodulating selector receives a WDM input signal, selects a particular optical channel from the WDM signal and places the information from the selected signal onto a newly-generated optical output signal. The wavelength of the output optical signal can be the same as or different from one of the optical channels which comprises the WDM input signal. When used in a WDM optical communication system with remodulators at the transmission input, the remodulating selectors provide complete control over the interfaces with optical transmitters and receivers, permitting use with a broad range of optical equipment.

US Patent:

8306424, Nov 6, 2012

Filed:

Aug 24, 2010

Appl. No.:

12/862419

Inventors:

Stephen B. Alexander - Millersville MD, US
Steve W. Chaddick - Annapolis MD, US
Roy C. Litz - Freeland MD, US
Cecil D. Smith - Severna Park MD, US

Assignee:

Ciena Corporation - Hanover MD

International Classification:

H04J 14/02

US Classification:

398 79, 398 43, 398 82, 398 97, 398160

Abstract:

The present invention provides a remodulating channel selector for a wavelength division multiplexed optical communication system. The remodulating selector receives a WDM input signal, selects a particular optical channel from the WDM signal and places the information from the selected signal onto a newly-generated optical output signal. The wavelength of the output optical signal can be the same as or different from one of the optical channels which comprises the WDM input signal. When used in a WDM optical communication system with remodulators at the transmission input, the remodulating selectors provide complete control over the interfaces with optical transmitters and receivers, permitting use with a broad range of optical equipment.

US Patent:

8582705, Nov 12, 2013

Filed:

Dec 10, 2007

Appl. No.:

11/953305

Inventors:

Michael Y. Frankel - Baltimore MD, US
John P. Mateosky - West River MD, US
Stephen B. Alexander - Annapolis MD, US

Assignee:

Ciena Corporation - Hanover MD

International Classification:

H04L 7/00

US Classification:

375354, 327141, 370503, 709248, 713375, 714 12

Abstract:

The present invention provides a serializer/deserializer (SERDES) circuit that can cover both client- and network-side interfaces for high-speed data rates. The present invention leverages commonality between the client and network (also known as line) side, and accommodates differences in a flexible manner. In one exemplary embodiment, the present invention provides a four-channel implementation to meet the requirement of both interfaces. The SERDES circuit can be capable of supporting both 40 Gb/s and 56 Gb/s data rates, can include an integrated DQPSK pre-coder and I/Q input/output signals, and can support RZ clock recovery. Additionally, the SERDES circuit can include differential coding support, electronic pre-emphasis, receiver-side electronic dispersion compensation, and the like.

US Patent:

55328644, Jul 2, 1996

Filed:

Jun 1, 1995

Appl. No.:

8/457292

Inventors:

Stephen B. Alexander - Millersville MD
Steve W. Chaddick - Annapolis MD
David R. Huber - Annapolis MD

Assignee:

Ciena Corporation - Columbia MD

International Classification:

H04B 1002
H01S 300

US Classification:

359177

Abstract:

The present invention provides a wavelength division multiplexed optical communication system which includes an optical monitoring channel which is capable of surviving the failure of an optical amplifier. The optical communication system comprises a plurality of optical transmitters which optically communicate with an optical waveguide which carries the multiplexed optical transmission signal. At least one multiple-stage optical amplifier having at least first and second stages is positioned along said optical waveguide. The optical amplifier includes a first and second stages comprising doped fibers having a first gain wavelength band. An optical connecting element having a plurality of ports is positioned between the first and second stages. At least one of an optical monitoring signal transmitter and an optical monitoring signal receiver optical communicates with at least one port of the optical connecting element such that the optical monitoring signal passes through at least one of the first and second stages of the optical amplifier. The optical monitoring signal wavelength is selected to be greater than the longest wavelength of the first gain wavelength band such that the optical monitoring signal is not substantially attenuated by an unpumped optical amplifier.