05532864 is referenced by 69 patents and cites 20 patents.

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. Therefore, in the event of a pump failure to at least a portion of an optical amplifier, the optical monitoring signal will still be transmitted through the that portion of the amplifier without substantial attenuation. In this manner, a wavelength division multiplexed optical communication system is provided with optical monitoring channels which do not occupy a portion of the amplifier gain spectrum and which can survive the failure of an optical amplifier.

Title
Optical monitoring channel for wavelength division multiplexed optical communication system
Application Number
8/457292
Publication Number
5532864
Application Date
June 1, 1995
Publication Date
July 2, 1996
Inventor
David R Huber
Annapolis
MD, US
Steve W Chaddick
Annapolis
MD, US
Stephen B Alexander
Millersville
MD, US
Agent
Margaret A Burke
Assignee
Ciena Corporation
MD, US
IPC
H01S 3/00
H04B 10/02
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