The routing problem in optical network is defined as determining individual wavelength paths in a Dense Wave Division Multiplexing (DWDM) network considering functions such as regeneration, amplification, Reconfigurable Optical Add/Drop Multiplexers (ROADMs), Fixed Optical Add/Drop Multiplexes (FOADMs), optical cross connects, wavelength converters, and the like. Some descriptions of this are in IETF RFC 6163 “Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs),” April 2011, the contents of which are incorporated by reference herein. In addition to the aforementioned functions, other aspects in routing include wavelength continuity, non-linear impairments, and the like. As such, routing of individual optical channels can be an extremely complex proposition. As technology evolves, impairment effects, signal loss, etc. are becoming less applicable in the routing considerations. This is also the case in campus, metro, and/or regional networks in which degree size (e.g., typically four or less) and distance are such that various aspects can be eliminated in the routing problem. Further, conventional photonic networks cannot perform restoration from line faults at the speed expected for protection. By photonic, this refers to switching at the wavelength level as opposed to switching at a Time Division Multiplexing (TDM) level (e.g., Optical Transport Network (OTN), Synchronous Optical Network (SONET, Synchronous Digital Hierarchy (SDH), etc.).
Two exemplary photonic networks include a broadcast and select optical network and an all-broadcast optical network. The broadcast and select optical network forms individual nodes based on WSSs and 1: N splitters to form a ROADM degree architecture. Examples of broadcast and select optical networks are described in commonly assigned U.S. patent application Ser. No. 11/970,575 filed Jan. 8, 2008 and entitled “WAVELENGTH-SWITCHED OPTICAL ADD-DROP MULTIPLEXER WITH WAVELENGTH BROADCASTING CAPABILITY” and commonly assigned U.S. patent application Ser. No. 12/103,204 filed Apr. 15, 2008 and entitled “DIRECTIONLESS RECONFIGURABLE OPTICAL ADD-DROP MULTIPLEXER SYSTEMS AND METHODS,” the contents of each are incorporated by reference herein. Examples of all-broadcast optical networks are described in commonly assigned U.S. patent application Ser. No. 12/436,470 filed May 6, 2009 and entitled “OPTICAL ROUTING DEVICE AND OPTICAL NETWORK USING SAME” and commonly assigned U.S. patent application Ser. No. 13/371,920 filed Feb. 13, 2012 and entitled “COLORLESS, DIRECTIONLESS, AND GRIDLESS OPTICAL NETWORK, NODE, AND METHOD,” the contents of each are incorporated by reference herein.
USPTO Backgrounds
USPTO Backgrounds