Optical network architecture for hierarchical modulation

摘要

A disclosed optical transport system is configured to use hierarchical modulation for better utilization of the available BER margin, e.g., to increase data-transport capacity per carrier wavelength in the system. For example, hierarchical modulation may be used to reduce the number of carrier wavelengths assigned to support a given volume of bidirectional data transport between a set of nodes in an optical backbone network. An embodiment of the disclosed optical transport system can advantageously be constructed by modifying a conventional WDM system, e.g., by adding configurable hierarchical-layer mappers at some of the nodes and modifying some of the ROADMs used therein to enable a drop-and-continue mode of operation.

主权项

1. A system comprising:
a first node configured to generate, for transmission over an optical path, a first hierarchically modulated optical signal having a base layer and an enhancement layer; and a second node configured to generate, for transmission over the optical path, a second hierarchically modulated optical signal having a base layer and an enhancement layer, wherein:
the first node is further configured to receive data from the second node by demodulating and decoding either the base layer or the enhancement layer of the second hierarchically modulated optical signal; andthe second node is further configured to receive data from the first node by demodulating and decoding either the base layer or the enhancement layer of the first hierarchically modulated optical signal; wherein the first node comprises:
a sorter configured to sort data frames received for transmission over the optical path in accordance with destination; anda cross-connect switch configured to distribute the data frames sorted by the sorter to a plurality of coding modules; and wherein the cross-connect switch is further configured to:
direct the data frames having a first destination to a first coding module of the plurality of coding modules, said first coding module being configured to encode the data frames directed thereto by the cross-connect switch for transmission over the optical path using a base layer of a designated hierarchically modulated optical signal; anddirect the data frames having a second destination to a second coding module of the plurality of coding modules, said second coding module being configured to encode the data frames directed thereto by the cross-connect switch for transmission over the optical path using an enhancement layer of the designated hierarchically modulated optical signal.