| US 7,499,652 B2 | ||
| Modular add/drop multiplexer including a wavelength selective switch | ||
| Shan Zhong, Ellicott City, Md. (US); and Charles Haggans, Boulder, Colo. (US) | ||
| Assigned to Ciena Corporation, Linthicum, Md. (US) | ||
| Filed on Sep. 14, 2007, as Appl. No. 11/855,427. | ||
| Application 11/855427 is a division of application No. 10/768057, filed on Feb. 02, 2004, granted, now 7,308,197. | ||
| Claims priority of provisional application 60/444284, filed on Jan. 31, 2003. | ||
| Claims priority of provisional application 60/443898, filed on Jan. 31, 2003. | ||
| Prior Publication US 2008/0002974 A1, Jan. 03, 2008 | ||
| Int. Cl. H04J 14/02 (2006.01) | ||
| U.S. Cl. 398—83 [398/48] | 7 Claims |
| 1. An expandable network element, comprising:
a wavelength selective switch having a plurality of input ports and a plurality of output ports, each of said plurality of
input ports being coupled to a respective one of a plurality of input optical communication paths, and each of said plurality
of output ports being coupled to a respective one of a plurality of output optical communication paths, wherein one of said
input optical communication paths carries an optical service channel;
a plurality of first optical splitters, each of said plurality of first optical splitters being coupled to a respective one
of said plurality of input optical communication paths;
a second optical splitter having an input coupled to one of said first plurality of optical splitters, a first output and
a second output;
an optical demultiplexer coupled to said first output, said second output being a supplemental output not coupled to an optical
demultiplexer, wherein said optical demultiplexer comprises a plurality of optical filtering elements, each of said optical
filtering elements being tunable;
an additional optical demultiplexer coupled to said input optical communication path, said additional optical demultiplexer
being configured to select said optical service channel; and
a control circuit coupled to said additional demultiplexer and said optical demultiplexer, said control circuit being configured
to control said optical filtering elements in response to said optical service channel.
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