Multiple interconnected broadcast and select optical ring networks with revertible protection switch

• US 20060275035A1
• Filed: 05/02/2006
• Published: 12/07/2006
• Est. Priority Date: 05/02/2005
• Status: Abandoned Application

• Current Assignee: Vello Systems Incorporated
• Original Assignee: Vello Systems Incorporated
• Inventors: Way, Winston I.
• Application Number:
  US11/416,796
• Publication Number:
  US 20060275035A1
• Time in Patent Office: Days
• US Class Current: 398/59
• CPC Class Codes: H04B 10/27 Arrangements for networking
• CPC Class Codes: H04B 10/271 Combination of different networks, e.g. star and ring configuration in the same network or two ring networks interconnected
• CPC Class Codes: H04B 10/275 Ring-type networks
• CPC Class Codes: H04B 10/2755 Ring-type networks with a headend
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/02216 by gain equalization
• CPC Class Codes: H04J 14/0232 for downstream transmission
• CPC Class Codes: H04J 14/0235 for upstream transmission
• CPC Class Codes: H04J 14/0275 using an optical service channel
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0286 WDM hierarchical architectures
• CPC Class Codes: H04J 14/0291 Shared protection at the optical multiplex section (1:1, n:m)

Abstract

Optical communication networks having multiple interconnected optical rings and optical protection switching mechanism to reduce communication delays and improve optical signal-to-noise ratios. Optical ring networks using variable optical attenuators for protection switching are also described.

Claims

1. A method for optical communications, comprising:

dividing optical communication nodes in a given service area into a plurality of groups of communication nodes that are in different areas within the given service area;

linking communication nodes in each group to form a single broadcast-and-select ring network so that a plurality of broadcast-and-select single ring networks are formed in the groups, respectively;

interconnecting the single ring networks to allow for direct optical communications between any two of the single ring networks so that each single ring network has a junction node that is optically linked to other single ring networks;

providing a gate node in each single ring network that is located at or near a middle location in the single ring network with respect to the junction node, wherein the gate node has a switching mechanism to close or open an optical link at the gate node in response to a control signal; and

closing an optical link in a gate node in a single ring network when there is an optical break in the single ring network while keeping the optical link in gate nodes in other single ring networks closed.

2. The method as in claim 1, further comprising using at least one variable optical attenuator in a gate node to achieve the switching mechanism.

3. The method as in claim 1, further comprising using at least one optical switch in a gate node to achieve the switching mechanism.

4. The method as in claim 1, further comprising using at least one broadband optical coupler at the junction node to couple optical signals between different single ring networks so that any node in any single ring can communicate with any other node in the same ring or different rings.

5. The method as in claim 1, further comprising using an optical link to connect two junction nodes in two separate single ring networks.

6. The method as in claim 1, further comprising using a single junction node to be shared by and to link all single ring networks.

7. The method as in claim 1, further comprising configuring the single ring networks to have equal or approximately equal ring circumferences.

8. The method as in claim 1, comprising using an optical switch as the gate switch which has an open position and a close position.

9. The method as in claim 1, comprising using a variable optical attenuator as the gate switch which has a maximum attenuation sufficiently to turn off optical transmission.

10. The method as in claim 1, further comprising reverting a gate node in a single ring network back to open after a break in the single ring network which causes the gate node to close the optical link at the node gate is repaired.

11. The method as in claim 1, further comprising using at least one optical amplifier in a gate node to achieve the switching mechanism.

12. The method as in claim 1, further comprising:

providing a variable optical attenuator in a communication node to control light power through the communication node; and

increasing an attenuation of the variable optical attenuator when a fiber break occurs next to the node to block optical transmission.

13. The method as in claim 12, further comprising:

measuring leakage light through the variable optical attenuator next to the fiber break; and

decreasing the attenuation of the variable optical attenuator upon detection of the leakage light after the fiber break is repaired while simultaneously opening the optical link in the gate node.

14. An optical ring network, comprising:

optical communication nodes connected to form an optical ring, wherein at least a portion of the nodes are configured to include at least one variable optical attenuator (VOA) which has a maximum optical attenuation at which optical transmission through the VOA is prohibited; and

a protection switching mechanism to detect an optical failure in the ring and to select at least one node to control the VOA in the selected node to prohibit optical transmission when an optical failure is detected.

15. The network as in claim 14, wherein the optical ring is a dual-fiber ring.

16. The network as in claim 14, wherein the optical ring is a single fiber ring.