EDGE-WAVELENGTH-SWITCHING SYSTEM, ASSOCIATED OPTICAL NETWORK, AND FAILOVER RECOVERY METHOD THEREOF

• US 20200136742A1
• Filed: 10/29/2019
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Campos, Luis Alberto, Wang, Jing, Jia, Zhensheng, Campanell, Jim, Stuart, Carmela, Zhang, Haipeng
• Granted Patent: US 11,271,669 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 10/03 Arrangements for fault recovery
• CPC Class Codes: H04B 10/07953 Monitoring or measuring OSNR, BER or Q
• CPC Class Codes: H04B 10/25891 Transmission components H04B10/40 takes precedence
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0205 Select and combine arrangements, e.g. with an optical combiner at the output after adding or dropping
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0216 Bidirectional architectures
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 11/0062 Network aspects
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0081 Fault tolerance; Redundancy; Recovery; Reconfigurability
• CPC Class Codes: H04Q 2011/0098 Mesh
• CPC Class Codes: H04Q 2213/1301 Optical transmission, optical switches

Abstract

An edge wavelength-switching system includes an optical switch and a wavelength selective switch. The optical switch includes a west hub-side port, an east hub-side port, a west local-side port, and an east local-side port. The wavelength selective switch includes (i) a multiplexed port optically coupled to the west local-side port and (ii) a bypass port optically coupled to the east local-side port, and (iii) a plurality of demultiplexed ports. An optical network includes a network hub including an M-by-N₁ wavelength-selective switch, N₁>M≥1, a first network node, and a second network node. Each of the first and second network nodes includes a respective edge wavelength-switching system. The network hub, the first network node, and the second network node are optically coupled.

Claims

1. An edge wavelength-switching system comprising:

an optical switch including a west hub-side port, an east hub-side port, a west local-side port, and an east local-side port; and

a wavelength selective switch including (i) a multiplexed port optically coupled to the west local-side port and (ii) a bypass port optically coupled to the east local-side port, and (iii) a plurality of demultiplexed ports.

2. The system of claim 1, the plurality of demultiplexed ports being N₁ in number, the west hub-side port, the east hub-side port, and D₁ of the plurality of demultiplexed ports functioning as a plurality of input/output ports of the system, wherein D₁ is less than or equal to N₁, and a total number of the plurality of input/output ports equaling (D₁+2).

3. The system of claim 1, the plurality of demultiplexed ports being N₁ in number,

the west hub-side port, the east hub-side port, and D₁ of the plurality of demultiplexed ports functioning as a plurality of input/output ports of the system, wherein D₁ is less than or equal to N₁;

the system lacking a receiver between any two input/output ports of the plurality of input/output ports.

4. The system of claim 1, further comprising:

a bidirectional optical amplifier optically coupling the west local-side port to the multiplexed port.

5. The system of claim 1, the optical switch being configured to operate in both (i) a parallel mode, in which the west and east hub-side ports are optically coupled to the west and east local-side ports respectively, and (ii) a crossed mode, in which the west and east hub-side ports are optically coupled to the east and west local-side ports respectively.

6. The system of claim 1, the edge wavelength-switching system lacking any additional wavelength selective switches other than the wavelength selective switch.

7. The system of claim 1, the wavelength selective switch further including:

a switching mechanism configured to route an optical signal entering the wavelength selective switch via the multiplexed port to any of the plurality of demultiplexed ports according to a center wavelength of the optical signal,

the switching mechanism including at least one of (i) microelectromechanical mirrors, (ii) a liquid-crystal polarizer, (iii) a liquid-crystal-on-silicon beam steerer, and (iv) tunable optical resonators.

8. An optical network comprising:

a network hub including an M-by-N₁ wavelength-selective switch, N₁>

M≥

1;

a first network node including a first instance of the edge wavelength-switching system of claim 1; and

a second network node including a second instance of the edge wavelength-switching system of claim 1;

the network hub, the first network node, and the second network node being optically coupled.

9. The optical network of claim 8, the first network node being optically coupled, via a demultiplexed port of its plurality of demultiplexed ports, to premise host equipment that includes a transceiver, the optical network further comprising:

a processor communicatively coupled to the first network node; and

a memory configured to store (i) a temporal sequence of bit-error rates received from the transceiver and (ii) non-transitory computer-readable failover instructions that, when executed by the processor, control the processor to;

determine a bit-error-rate severity from the temporal sequence of bit-error rates; and

control the optical switch of the first network node to switch from normal mode to failover mode when the bit-error-rate severity exceeds a predetermined severity threshold.

10. The optical network of claim 9, the network hub including:

an optical switch including a hub-side port A, a hub-side port B, a local-side port A, and a local-side port B; and

a 2-by-N₃ wavelength selective switch including (i) a first multiplexed port optically coupled to the hub-side port A, (ii) a second multiplexed port optically coupled to the hub-side port B, and (iii) N₃ demultiplexed ports, and (iv) a switching mechanism configured to optically couple to any of the N₃ demultiplexed ports to either the first or the second multiplexed port, N₃>

2.

11. The optical network of claim 10, the memory further comprising:

a frequency map that includes a plurality of frequency sub-bands each designated as one of a drop sub-band and a bypass sub-band; and

non-transitory computer-readable wavelength-routing instructions that, when executed by the processor, control the first network node to;

route each of the bypass sub-bands to the bypass port of the wavelength selective switch of the first network node.

12. The optical network of claim 10, further comprising:

a first bidirectional optical amplifier optically coupling the first multiplexed port to the hub-side port A; and

a second bidirectional optical amplifier optically coupling the second multiplexed port to the hub-side port B.

13. The optical network of claim 9, the network hub including:

a fiber-optic splitter including a hub-side splitter-port, a first local-side splitter-port, and a second local-side splitter-port; and

a 1-by-N₃ wavelength selective switch including (i) a first multiplexed port optically coupled to the hub-side splitter-port, (ii) N₃ demultiplexed ports, and (iii) a means to optically couple to any of the N₃ demultiplexed ports to the first multiplexed port, N₃>

1.

14. The optical network of claim 12, the memory further comprising:

a frequency map that includes a plurality of frequency sub-bands spanning a frequency range and each designated as one of a drop sub-band and a bypass sub-band; and

non-transitory computer-readable wavelength-routing instructions that, when executed by the processor, control the first network node to;

route bypass frequencies to the bypass port of the wavelength selective switch of the first network node, bypass frequencies including all frequencies within the frequency range and not part of a drop sub-band.

15. The optical network of claim 8, the network hub, the first network node, and the second network node being optically coupled via one of a ring topology and a bus topology.

16. The optical network of claim 8, the network hub including a hub-output port and a hub-input port, the optical switch of the first network node including a first west hub-side port and a first east hub-side port, the optical switch of the second network node including a second west hub-side port and a second east hub-side port, and further comprising:

a first optical fiber segment optically coupling the first west hub-side port to the hub-output port;

a second optical fiber segment optically coupling the first east hub-side port to the second west hub-side port; and

a third optical fiber segment optically coupling the second east hub-side port to the hub-output port.

17. A failover recovery method for an optical network, the method comprising:

determining a bit-error-rate severity from a temporal sequence of bit-error rates generated at a first premise host equipment optically coupled to a network node, of the optical network, that is optically coupled to a hub of the optical network via a first optical-fiber path; and

when the bit-error-rate severity exceeds a predetermined value, rerouting optical signals transmitted between the first premise host equipment and the hub such that the optical signals travel along a second optical-fiber path differing from the first optical-fiber path.

18. The method of claim 17, further comprising:

transmitting a random bit stream from a second premise host equipment to a transceiver of the first premise host equipment via a hub of the optical network and the network node; and

generating, at the first premise host equipment, the temporal sequence of bit-error rates from the random bit stream.

19. The method of claim 17, rerouting optical signals including controlling an optical switch of the network node to switch from normal mode to failover mode.

20. The method of claim 17, further comprising:

determining the bit-error-rate severity by computing a number of consecutive bit-error rates of the temporal sequence of bit-error rates that exceeds a predetermined threshold bit-error-rate value.