Fully protected broadcast and select all optical network

• US 7,499,647 B2
• Filed: 01/06/2003
• Issued: 03/03/2009
• Est. Priority Date: 05/22/2000
• Status: Expired due to Term

• Current Assignee: Snell Holdings, LLC (Treq Labs, Inc.)
• Original Assignee: Opvista, Inc. (Vello Systems Incorporated)
• Inventors: Way, Winston, Shi, Chao Xiang
• Primary Examiner(s): Leung, Christina Y
• Application Number:
  US10/338,088
• Publication Number:
  US 20030180047A1
• Time in Patent Office: 2,248 Days
• Field of Search: 398/3, 398/4, 398/59, 398/83, 398/84, 398/85, 398/87
• US Class Current: 398/3
• CPC Class Codes: H04B 10/503 Laser transmitters
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/564 Power control
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0294 Dedicated protection at the optical channel (1+1)
• CPC Class Codes: H04J 14/0295 Shared protection at the optical channel (1:1, n:m)
• CPC Class Codes: H04J 14/0297 Optical equipment protection
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085

Abstract

An all optical network for optical signal traffic provides at least a first ring with at least a first clockwise fiber, a second counter-clockwise fiber and a plurality of network nodes. Each node has at least a WDM transponder that with a line-side transmitter and a client-side receiver in a first direction, and a line-side receiver and a client-side transmitter in an opposing second direction. The line-side receiver includes a fixed or a tunable optical wavelength filter. At least a first add and a first drop broadband couplers are positioned on each fiber. Each coupler has first and second ports for through traffic and a third port for adding or dropping local traffic. The first add and first drop broadband couplers are configured to minimize a pass-through loss in each fiber. If there are multiple WDM transponders, their wavelengths are added to the ring either in series or in parallel. All wavelengths dropped from the ring are selected by each individual WDM transponder in a parallel or serial manner.

Claims

1. An all optical network for optical signal traffic, comprising:

a first ring with at least a first clockwise fiber, a second counter-clockwise fiber and a plurality of network nodes;

each node including at least a WDM transponder that includes a line-side transmitter and a client-side receiver in a first direction, and a line-side receiver and a client-side transmitter in an opposing second direction;

the line-side receiver including a fixed or a tunable optical wavelength filter;

at least a first add and a first drop broadband or narrowband couplers positioned on each fiber, each coupler having first and second ports for through traffic and a third port for adding or dropping local traffic, the first add and first drop broadband couplers being configured to minimize a pass-through loss in each fiber;

a first coupler pair including first and second couplers in each network node, the first coupler having first and second output ports and a first input port coupled to a line-side transmitter, the first output port being coupled to the clockwise fiber and the second output port being coupled to the counter-clockwise fiber;

the first coupler enabling the line-side transmitter to launch signals to both the clockwise and counter-clockwise fibers;

the second coupler having first and second input ports and a first output port coupled to a line-side receiver, the first input port being coupled to the clockwise fiber and the second input port coupled to the counter-clockwise fiber;

the second coupler enabling the line-side receiver to receive signals from both the clockwise and counter-clockwise fibers; and

a single hub switch coupled in the first clockwise and second counter-clockwise fibers as a central protection switch to open an optical break point in each of the first clockwise and second counter-clockwise fibers when there is no other break point in the first clockwise and second counter-clockwise fibers and to close the optical break point when there is a break point in at least one of the first clockwise and second counter-clockwise fibers.

2. The network of claim 1, wherein each of the broadband couplers on the ring is used in combination with one or more optical amplifiers configured to compensate for add/drop loss on the first ring.

3. The network of claim 2, wherein an input of each in-line amplifier is at a position where power levels of all wavelengths are equalized.

4. The network of claim 1, farther comprising:

one or more WDM transponders at each node.

5. The network of claim 4, wherein the one or more WDM transponders in each node are combined by one or more multi-port broadband power combiners.

6. The network of claim 4, wherein the one or more WDM transponders in each node are cascaded in series through narrowband optical add-drop filters.

7. The network of claim 1, wherein the first ring includes a plurality of nodes.

8. The network of claim 1, wherein the network is a passive optical network without in-line optical amplifiers and optical switches.

9. The network of claim 1, wherein the network is a non-passive network with at least one in-line optical amplifier.

10. The all optical network of claim 9, wherein at least one of the clockwise fiber or the counter-clockwise fiber is a working fiber, and the other is a protection fiber, wherein optical signal traffic travels in a clockwise direction in the clockwise fiber and in a counter-clockwise direction in the counter-clockwise fiber.

11. The network of claim 10, further comprising:

a central hub node in which the single hub switch is located.

12. The network of claim 11, wherein the central hub node includes at least one 1×

2 switch to couple transmitter power to at least one of the working fiber or the protection fiber.

13. The network of claim 12, further comprising:

a 1×

2 coupler at a receiving end at each node to receive signals from the working and protection fibers.

14. The network of claim 11, wherein the central hub includes at least a 1×

2 coupler to couple transmitter power to the working and protection fibers.

15. The network of claim 11, wherein each node at the receiving end includes a 1×

2 switch to receive a transmitter signal from at least one of the working or protection fibers.

16. The network of claim 11, wherein the central hub node includes at least one of a wavelength combining or a splitting device.

17. The network of claim 16, wherein the wavelength combining or splitting device includes at least a pair of 1×

N DWDM multiplexers, at least a pair of 1×

N DWDM demultiplexers, and at least one transponder coupled to the first working fiber and the first protection fiber.

18. The network of claim 9, wherein a pair of open 1×

1 switches are maintained on the working and protection fibers on the first ring to reduce a fiber ring lasing phenomenon in response to gain provided by in-line amplifiers coupled to the first ring.

19. The network of claim 1 further comprising at least one of, a wavelength-dependent fixed filter or a tunable filter, in front of the line-side receiver to filter light received by the line-side receiver.

20. An all optical network for optical signal traffic, comprising:

a first ring with at least a clockwise and a counter-clockwise fibers and a plurality of network nodes;

at least a first add and a first drop broadband couplers positioned on each fiber, each coupler having first and second ports for through traffic and a third port for adding or dropping local traffic, the first add and first drop broadband couplers being configured to minimize a pass-through loss in each fiber; and

a working WDM transponder coupled to the first ring, the working WDM transponder including a line-side transmitter and a client-side receiver in a first direction, and a line-side receiver and a client-side transmitter in an opposing second direction, the client side transmitter and the client side receiver of the working WDM transponder being coupled to a receiver and a transmitter of the working client side equipment respectively;

a protection WDM transponder coupled to the first ring, the protection WDM transponder including a line-side transmitter and a client-side receiver in a first direction, and a line-side receiver and a client-side transmitter in an opposing second direction, the client side transmitter and the client side receiver of the protection WDM transponder being coupled to a receiver and a transmitter of the protection client side equipment respectively; and

first and second coupler pairs, each pair including first and second couplers, the first coupler pair coupled to the working WDM transponder and the second coupler pair coupled to the protection WDM transponder, the first coupler having first and second output ports and a first input port coupled to the WDM transponder line-side transmitter, the first output port being coupled to the clockwise fiber and the second output port being coupled to the counter-clockwise fiber;

the first coupler enabling the WDM transponder line-side transmitter to launch signals to both the clockwise and counter-clockwise fibers, the second coupler having first and second input ports and a first output port coupled to the WDM transponder line-side receiver, the first input port being coupled to the clockwise fiber and the second input port being coupled to the counter-clockwise fiber;

the second coupler enabling the WDM transponder line-side receiver to receive signals from both the clockwise and counter-clockwise fibers; and

a single hub switch coupled in the first clockwise and second counter-clockwise fibers as a central protection switch to open an optical break point in each of the first clockwise and second counter-clockwise fibers when there is no other break point in the first clockwise and second counter-clockwise fibers and to close the optical break point when there is a break point in at least one of the first clockwise and second counter-clockwise fibers.

21. The network of claim 20, further comprising:

one or more WDM transponders at each node.

22. The network of claim 21, wherein the one or more WDM transponders at each node are combined by one or more multi-port broadband power combiners.

23. The network of claim 21, wherein the one or more WDM transponders at each node are cascaded in series through narrowband optical add-drop filters.

24. An all optical network for optical signal traffic, comprising:

a first ring with at least a first clockwise and a second counter-clockwise fibers and a plurality of network nodes;

at least a first add and a first drop broadband or narrowband couplers positioned on each fiber, each coupler having first and second ports for through traffic and a third port for adding or dropping local traffic, the first add and first drop broadband couplers being configured to minimize a pass-through loss in each fiber;

a working WDM transponder coupled to the first ring, the working WDM transponder including a line-side transmitter and a client-side receiver in a first direction, and a line-side receiver and a client-side transmitter in an opposing second direction, the client side transmitter and the client side receiver of the working WDM transponder connected back to back to a receiver and a transmitter of working client equipment respectively;

a protection WDM transponder coupled to the first ring, the protection WDM transponder including a line-side transmitter and a client-side receiver in a first direction, and a line-side receiver and a client-side transmitter in an opposing second direction, the client side transmitter and the client side receiver of the protection WDM transponder coupled to a receiver and a transmitter of the protection client side equipment respectively;

first and second coupler pairs, each pair including first and second couplers, the first coupler pair coupled to the working WDM transponder and the second coupler pair coupled to the protection WDM transponder, the first coupler having first and second output ports and a first input port coupled to the WDM transponder line-side transmitter, the first output port being coupled to the clockwise fiber and the second output port being coupled to the counter-clockwise fiber;

the first coupler enabling the WDM transponder line-side transmitter to launch signals to both the clockwise and counter-clockwise fibers, the second coupler having first and second input ports and a first output port coupled to the WDM transponder line-side receiver, the first input port being coupled to the clockwise fiber and the second input port being coupled to the counter-clockwise fiber;

the second coupler enabling the WDM transponder line-side receiver to receive signals from both the clockwise and counter-clockwise fibers;

a 1×

2 coupler configured to launch client optical signals to the WDM working transponder and the WDM protection transponder;

a 1×

2 coupler configured to permit client equipment to receive signals from either the working WDM transponder or the protection WDM transponder, wherein a client-side transmitter on the WDM equipment is turned off to reduce coherent crosstalk and interference; and

a single hub switch coupled in the first clockwise and second counter-clockwise fibers as a central protection switch to open an optical break point in each of the first clockwise and second counter-clockwise fibers when there is no other break point in the first clockwise and second counter-clockwise fibers and to close the optical break point when there is a break point in at least one of the first clockwise and second counter-clockwise fibers.

25. The network of claim 24, further comprising:

one or more WDM transponders at each node.

26. The network of claim 25, wherein the one or more WDM transponders at each node are combined by one or more multi-port broadband power combiners.

27. The network of claim 25, wherein the one or more WDM transponders at each node are cascaded in series through narrowband optical add-drop filters.

28. An optical communication system, comprising:

a ring network comprising a first fiber ring to carry clockwise optical signals, a second fiber ring to carry counter-clockwise optical signals, and a plurality of network nodes coupled to send light to and to receive light from each of the first and second fiber rings,

wherein each network node comprises;

a first pair of optical couplers coupled to the first and second fiber rings, respectively, to add at least one optical add signal to the first and second fiber rings, respectively, and to transmit optical signals in the first and second fiber rings,

a node add means for directing the optical add signal into the first pair of optical couplers,

a second pair of optical couplers coupled to the first and second fiber rings, respectively, to drop at least one portion of light from each of the first and second fiber rings, respectively, as an optical drop signal and to transmit remaining light in the first and second fiber rings, where the optical drop signal and the optical add signal are at different optical wavelengths,

a node drop means for receiving the optical drop signal from the second pair of optical couplers as a drop signal, and

a node transponder to produce the optical add signal to the node add means and to receive the drop signal from the node drop means; and

wherein the ring network further comprises;

a single hub switch coupled in the first and second fiber rings as a central protection switch to open an optical break point in each of the first and second fiber rings when there is no other break point in the first and second fiber rings and to close the optical break point when there is a break point in at least one of the first and second fiber rings.

29. The system as in claim 28, wherein the node add means comprises a first optical coupler and the node drop means comprises a second optical coupler.

30. The system as in claim 28, wherein each network node further comprises a protection equipment in communication with the first and second fiber rings to provide redundancy protection of the network node in communication with the ring network, wherein the protection equipment comprises:

a first pair of protection optical couplers coupled to the first and second fiber rings, respectively, to add at least one optical add signal to the first and second fiber rings, respectively, and to transmit optical signals in the first and second fiber rings,

a protection equipment add means for directing the optical add signal into the first pair of add optical couplers,

a second pair of protection optical couplers coupled to the first and second fiber rings, respectively, to drop at least one optical drop signal from the first and second fiber rings, respectively, and to transmit other optical signals the first and second fiber rings,

a protection equipment drop means for receiving the optical add signal from the second pair of add optical couplers as a drop signal, and

a protection equipment transponder to produce the optical add signal to the node add optical coupler and to receive the drop signal from the node drop optical coupler.

31. The system as in claim 30, wherein the node transponder is coupled to client side working equipment to add a client side add signal to the first and second fiber rings and to drop a client side drop signal to the client side working equipment, and

wherein the protection equipment transponder is coupled to client side protection equipment different from the client side working equipment to add the client side add signal to the first and second fiber rings and to drop the client side drop signal to the client side protection equipment as a protection against a communication failure with the client side working equipment.

32. The system as in claim 31, wherein each of the node transponder and the protection equipment transponder comprises:

a line-side transmitter to produce the optical add signal to the node add means;

a client-side receiver to receive a client input signal;

a line-side receiver to receive the drop signal from the node drop means; and

a client-side transmitter to send a client output signal, wherein the client side transmitter and the client side receiver are connected to a receiver and a transmitter of the client equipment, respectively.

33. The system as in claim 30, wherein each network node further comprises:

a client side add optical coupling element to couple a first part of a client side optical add signal from client side equipment to the node transponder and a second part of the client side optical add signal to the protection equipment transponder; and

a client side drop optical coupling element to couple a first client side optical drop signal from the node transponder to the client side equipment and a second client side optical drop signal from the protection equipment transponder to the client side equipment.

34. The system as in claim 33, wherein each of the node transponder and the protection equipment transponder comprises:

a line-side transmitter to produce the optical add signal to the node add means;

a client-side receiver to receive a client input signal;

a line-side receiver to receive the drop signal from the node drop means; and

a client-side transmitter to send a client output signal, wherein the client side transmitter and the client side receiver are connected to a receiver and a transmitter of the client equipment, respectively.

35. The system as in claim 28, wherein the node transponder comprises:

a line-side transmitter to produce the optical add signal to the node add means;

a client-side receiver to receive a client input signal;

a line-side receiver to receive the drop signal from the node drop means; and

a client-side transmitter to send a client output signal, wherein the client side transmitter and the client side receiver are connected to a receiver and a transmitter of client equipment, respectively.

39. The system as in claim 30, further comprising a protection equipment at a site of each network node in communication with the first and second fiber rings to provide redundancy protection of the network node in communication with the ring network.

40. The system as in claim 39, wherein each network node and a corresponding protection equipment are both coupled to communicate with a common client equipment in communication with the ring network.

41. The system as in claim 40, further comprising:

an optical coupler to combined client-side optical transmission signals from the network node and the corresponding protection equipment as a client side optical output to the common client equipment; and

a mechanism to turn off optical transmission from the corresponding protection equipment to the common client equipment when the network node operates normally and to turn on optical transmission from the corresponding protection equipment to the common client equipment when the network node fails to transmit to the common client equipment.

42. The system as in claim 39, wherein each network node and a corresponding protection equipment are respectively coupled to communicate with client working equipment and separate client protection equipment which provides redundancy for the client working equipment in communication with the ring network.

36. An optical communication system, comprising:

a ring network comprising a first fiber ring to carry clockwise optical signals, a second fiber ring to carry counter-clockwise optical signals, a plurality of network nodes coupled to send light to and to receive light from each of the first and second fiber rings, and a single hub switch coupled in the first and second fiber rings to provide a central protection switching in the ring network,

wherein the single hub switch is controlled to open an optical break point in each of the first and second fiber rings when there is no other break point in the first and second fiber rings and to close the optical break point when there is a break point in at least one of the first and second fiber rings, and

wherein each network node is coupled to the first and second fiber rings to broadcast information to the ring network and to selectively receive information from the ring network, and

wherein each network node comprises;

a pair of add optical couplers coupled to the first and second fiber rings, respectively, to add at least one optical add signal to the first and second fiber rings, respectively, and to transmit light in the first and second fiber rings,

a node add element configured to direct the optical add signal into the pair of add optical couplers,

a pair of drop optical couplers coupled to the first and second fiber rings, respectively, to drop at least one portion of light from each of the first and second fiber rings, respectively, as an optical drop signal and to transmit remaining light in the first and second fiber rings, where the optical drop signal and the optical add signal are at different optical wavelengths,

a node drop element configured to receive the optical drop signal from the pair of drop optical couplers as a drop signal, and

a node transponder to produce the optical add signal to the node add element and to receive the drop signal from the node drop element,

wherein each network node does not have an optical switch to generate a physical break point in the first and second fiber rings.

37. The system as in claim 36, wherein the node transponder comprises a tunable optical filter that selects a wavelength of light in the drop optical signal and selectively detects an optical signal at the selected wavelength in the drop optical signal.

38. The system as in claim 36, wherein the node transponder further comprises:

a line-side transmitter to produce the optical add signal to the node add element;

a client-side receiver to receive a client input signal;

a line-side receiver comprising an tunable optical filter to select a wavelength of light in the drop optical signal and operating to detect an optical signal at the selected wavelength in the drop signal; and

a client-side transmitter to send a client output signal, wherein the client side transmitter and the client side receiver are connected to a receiver and a transmitter of the client equipment, respectively.

43. The system as in claim 36, wherein the hub switch comprises a first optical switch connected in the first fiber ring and a second optical switch connected in the second fiber ring.

44. The system as in claim 36, wherein the node add element is an optical switch to direct the optical add signal to either one of the pair of add optical couplers.

45. The system as in claim 36, wherein the node add element is an optical coupler to direct the optical add signal to each of the add optical couplers.

46. The system as in claim 36, wherein the node drop element is an optical switch to select one of the drop optical couplers to being connected to the node transponder which receives the drop signal from the selected drop optical coupler.

47. The system as in claim 36, wherein the node drop element is an optical coupler to couple the drop signals from both the drop optical couplers to the node transponder.