Optical Ring Networks Having Node-To-Node Optical Communication Channels For Carrying Data Traffic

An optical communication system, comprising:

• a plurality of optical ring nodes connected to form an optical ring having a first optical ring path to carry light through the optical ring nodes along a first direction and a second optical ring path to carry light through the optical ring nodes along a second, opposite direction,
• wherein the optical ring is configured to support (1) broadcast-and-select optical WDM signals carrying communication traffic to the optical ring nodes without regeneration at each optical ring node in each of the first and second optical ring paths, and (2) at least one node-to-node optical WDM signal carrying communication traffic from one optical ring node to an adjacent optical ring node by regeneration at each optical ring node in each of the first and second optical ring paths, and
• wherein each ring node comprises:
• a broadcast-and-select add and drop module to produce at least one of the broadcast-and-select optical WDM signals and to split a fraction of light in the broadcast-and-select optical WDM signals for detection while transmitting rest of the light in the broadcast-and-select optical WDM signals;
• a node-to-node optical transmitter to produce the node-to-node optical WDM signal;
• an optical coupler to receive the node-to-node optical WDM signal from the node-to-node optical transmitter and to split the node-to-node optical WDM signal into a first node-to-node optical WDM signal and a second node-to-node optical WDM signal;
• a first optical add coupler coupled to the first optical ring path to direct the first node-to-node optical WDM signal to the first optical ring path;
• a second optical add coupler coupled to the second optical ring path to direct the second node-to-node optical WDM signal to the second optical ring path;
• a first optical drop coupler coupled to the first optical ring path upstream from the first optical add coupler to selectively couple light of the first node-to-node optical WDM signal out of the first optical ring path while transmitting light of the broadcast-and-select optical WDM signals;
• a second optical drop coupler coupled to the second optical ring path upstream from the second optical add coupler to selectively couple light of the second node-to-node optical WDM signal out of the second optical ring path while transmitting light of the broadcast-and-select optical WDM signals;
• and
• an optical receiver coupled to receive the first and second node-to-node optical WDM signals from the first and second optical drop couplers.

The system as in claim 15, comprising:

• an optical probe transmitter coupled to the optical ring network to supply to the optical ring network an optical probe signal at a probe wavelength which is different from wavelengths of the broadcast-and-select optical WDM signals and the node-to-node optical WDM signal;
• a probe monitor in at least one optical ring node to split a portion of the optical probe signal and to monitor the optical probe signal to detect an optical failure in the optical ring network;
• and
• a protection switch in the optical ring network to create a default optical break point when the probe monitor indicates that there is no optical failure in the optical ring network and to close the default optical break point when the probe monitor indicates that there is an optical failure,
• wherein the optical ring network is responsive to a status of the monitored optical probe signal to control the protection switch and the optical ring nodes to sustain communications in the optical ring network outside a location of the optical failure and to restore communications in the optical ring network after the optical failure is repaired.

A method for optical communication in a ring network, comprising:

• using broadcast-and-select optical WDM signals at different wavelengths to carry communication traffic to optical ring nodes in the ring network, each optical ring node splitting a fraction of the broadcast-and-select optical WDM signals for detection while transmitting rest of light of the broadcast-and-select optical WDM signals to a next optical ring node;
• using at least one node-to-node optical WDM signal carrying node-to-node communication traffic from one optical ring node to an adjacent optical ring node by regeneration at each optical ring node, wherein the node-to-node optical WDM signal is at a wavelength different from wavelengths of the broadcast-and-select optical WDM signals;
• designating each broadcast-and-select optical WDM signal to a selected optical ring node for sending data from the selected optical ring node to one or more other optical ring nodes;
• and
• operating the optical ring nodes to share a bandwidth of the node-to-node optical WDM signal to transmit data from one optical ring node to one or more other optical ring nodes through the node-to-node communication traffic.