Methods and apparatus for reconfigurable add drop multiplexers
First Claim
1. A Reconfigurable Optical Add Drop Multiplexer (ROADM), comprising:
- add paths configured to add optical signals from tributary paths to inter-node network paths;
drop paths configured to drop optical signals from the inter-node network paths to tributary paths;
express paths configured to pass optical signals to the inter-node network paths, an insertion loss for the express paths being lower than an insertion loss of the add paths or drop paths; and
a wavelength-selective switch (WSS) optically disposed in the express paths, the WSS including multiple parallel non-cascaded sub-WSSs and an optical coupler optically coupled to the multiple parallel non-cascaded sub-WSSs.
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Accused Products
Abstract
Optical networks are increasingly employing optical network nodes having multiple interfaces to allow a node to direct optical signals received at any interface to any other interface connected to the node. Constructing a larger wavelength selective switching (WSS) module used in such a node can be complex and expensive. A method an apparatus for constructing a large WSS using parallelism is provided. In example embodiments, a larger WSS may include multiple parallel non-cascaded smaller WSSs and an optical coupler configured to optically couple the multiple parallel, non-cascaded smaller WSSs. This technique may be used to construct both N×1 and 1×N WSSs. Because the technique employs multiple parallel, non-cascaded WSSs, all inputs of a larger N×1 WSS and all outputs of a larger 1×N WSS are available receive or transmit external signals rather than being rather than being unavailable due to, for example, cascading smaller WSS devices together.
69 Citations
20 Claims
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1. A Reconfigurable Optical Add Drop Multiplexer (ROADM), comprising:
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add paths configured to add optical signals from tributary paths to inter-node network paths; drop paths configured to drop optical signals from the inter-node network paths to tributary paths; express paths configured to pass optical signals to the inter-node network paths, an insertion loss for the express paths being lower than an insertion loss of the add paths or drop paths; and a wavelength-selective switch (WSS) optically disposed in the express paths, the WSS including multiple parallel non-cascaded sub-WSSs and an optical coupler optically coupled to the multiple parallel non-cascaded sub-WSSs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of multiplexing optical signals at an optical node in an optical network with a reconfigurable optical add drop module (ROADM), the method comprising:
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adding optical signals from tributary paths to inter-node network paths by way of add paths; dropping optical signals from the inter-node network paths to tributary paths by way of drop paths; coupling express paths to the inter-node network paths an insertion loss for the express paths being lower than an insertion loss of the add paths or drop paths; performing parallel non-cascaded wavelength-selective switching with a wavelength-selective switch (WSS) of optical signals having multiple wavelengths; and coupling optical paths associated with the parallel non-cascaded wavelength-selective switching to a common optical path. - View Dependent Claims (11, 12, 13)
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14. An optical input block in a reconfigurable optical add drop multiplexer (ROADM) comprising:
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an input signal port configured to receive an optical input signal, the optical input signal including plural wavelengths; at least one dedicated express output port configured to transport multiple wavelengths to another ROADM device; at least one dedicated drop port configured to transport a single wavelength to an optical transponder device; at least one express drop port configured to operate as an express port or a drop port; and at least two wavelength filtering devices, the at least two wavelength filtering devices configured to direct the wavelengths to the at least one dedicated express port, the at least one dedicated drop port, and the at least one express drop port. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification