Method and apparatus for bridging optical signals in an optical network

• US 6,813,407 B2
• Filed: 08/26/2003
• Issued: 11/02/2004
• Est. Priority Date: 11/02/1999
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Ramaswami, Rajiv, Ward, Robert R.
• Primary Examiner(s): HEALY, BRIAN
• Application Number:
  US10/648,025
• Publication Number:
  US 20040076365A1
• Time in Patent Office: 434 Days
• Field of Search: 385/15, 385/16, 385/24, 385/88, 385/89, 398/45, 398/49, 398/50
• US Class Current: 385/16
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: H04J 14/0293 Optical channel protection
• CPC Class Codes: H04J 14/0297 Optical equipment protection
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 11/0062 Network aspects
• CPC Class Codes: H04Q 2011/0009 using wavelength filters
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)
• CPC Class Codes: H04Q 2011/0035 using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical
• CPC Class Codes: H04Q 2011/0041 Optical control
• CPC Class Codes: H04Q 2011/0043 Fault tolerance
• CPC Class Codes: H04Q 2011/005 Arbitration and scheduling
• CPC Class Codes: H04Q 2011/0058 Crossbar; Matrix
• CPC Class Codes: H04Q 2011/0073 Provisions for forwarding or routing, e.g. lookup tables
• CPC Class Codes: H04Q 2011/0081 Fault tolerance; Redundancy; Recovery; Reconfigurability
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring
• CPC Class Codes: H04Q 2011/0088 Signalling aspects

Abstract

Methods, apparatus and systems for regenerating, monitoring and bridging optical signals through an optical cross-connect switch to provide increased reliability. A self testing method, apparatus and system for an optical cross-connect switch. An optical-to-electrical-to-optical converter (O/E/O) is provided in an optical cross-connect switch to provide optical-electrical-optical conversion. I/O port cards having an optical-to-electrical-to-optical converter are referred to as smart port cards while I/O port cards without an optical-to-electrical-to-optical converter are referred to as passive port cards. Test port/monitor cards are also provided for testing optical cross-connect switches. Methods, apparatus and systems for performing bridging, test access, and supporting redundant optical switch fabrics are also disclosed.

Claims

1. A method of bridging optical signals in optical network equipment, the method comprising:

receiving an optical signal;

splitting the optical signal into at least two similar optical signals;

processing the at least two similar optical signals in the optical network equipment; and

selecting one of at least two outputs of the optical network equipment that has a resultant optical output signal responsive to the processing of one of the at least two similar optical signals in the optical network equipment.

2. The method of claim 1 wherein

the optical network equipment is an optical cross-connect switch and the processing of the at least two similar optical signals therein includes routing the at least two similar optical signals respectively over at least two optical paths to the at least two outputs.

3. The method of claim 1 wherein

one of the at least two outputs of the optical network equipment has failed and another of the at least two outputs is selected that has the resultant output responsive to the processing.

4. The method of claim 1 wherein

the splitting of the optical signal into the at least two similar optical signals and the processing of the at least two similar optical signals in the optical network equipment provides redundancy to increase reliability of the optical network equipment.

5. The method of claim 1 further comprising

prior to the splitting of the optical signal into the at least two similar optical signals, converting the optical signal into an electrical signal.

6. The method of claim 1 further comprising

converting the resultant optical output signal into an electrical signal.

7. The method of claim 6 further comprising

converting the electrical signal into an optical output signal from the optical network equipment.

8. An apparatus for bridging optical signals in optical network equipment comprising:

a splitter to split an input optical signal into the optical network equipment into two similar optical signals;

the optical network equipment to similarly process the two similar optical signals into two similar resultant optical output signals at two outputs if no failure exists; and

a switch to select one of the two outputs having a resultant optical output signal as the output optical signal from the optical network equipment.

9. The apparatus of claim 8 wherein

the optical network equipment is an optical cross-connect switch and the similar process of the two similar optical signals therein includes routing the two similar optical signals respectively over two optical paths to the two outputs.

10. The apparatus of claim 8 wherein

one of the two outputs of the optical network equipment is faulty and the other one of the two outputs is selected by the switch that has the resultant optical output signal as the output optical signal from the optical network equipment.

11. The apparatus of claim 8 wherein

the splitter and the optical network equipment provide redundancy for the input optical signal in generating the output optical signal to increase reliability of the optical network equipment.

12. The apparatus of claim 8 wherein

the splitter is an optical splitter.

13. The apparatus of claim 12 further comprising

an optical-electrical-optical converter to convert the input optical signal into an electrical signal and the electrical signal into an optical signal.

14. The apparatus of claim 13 wherein

the optical-electrical-optical converter and the optical splitter are in an input path of a smart port card of the optical network equipment.

15. The apparatus of claim 8 further comprising

an optical-electrical converter to convert the input optical signal into an electrical signal, and wherein the splitter includes

a first electrical-optical converter coupled to the optical-electrical converter, the first electrical-optical converter to convert the electrical signal into one of the two similar optical signals, and

a second electrical-optical converter coupled to the optical-electrical converter, the second electrical-optical converter to convert the electrical signal into another one of the two similar optical signals.

16. The apparatus of claim 8 wherein

the switch is an optical switch.

17. The apparatus of claim 16 further comprising

an optical-electrical-optical converter coupled to the optical switch, the optical-electrical-optical converter to convert the resultant optical output signal into an electrical signal and the electrical signal into the output optical signal from the optical network equipment.

18. The apparatus of claim 17 wherein

the optical-electrical-optical converter and the optical switch are in an output path of a smart port card of the optical network equipment.

19. The apparatus of claim 8 wherein

the switch includes

a first optical-electrical converter to convert one of the two resultant output signals into a first electrical signal,

a second optical-electrical converter to convert another one of the two resultant output signals into a second electrical signal,

a multiplexer coupled to the first optical-electrical converter to receive the first electrical signal and to the second optical-electrical converter to receive the second electrical signal, the multiplexer to select between the first electrical signal and the second electrical signal as its output electrical signal, and

an electrical-optical converter coupled to the multiplexer to receive the output electrical signal, the electrical-optical converter to convert the output electrical signal into the output optical signal of the optical network equipment.

20. An apparatus for bridging optical signals in optical network equipment comprising:

a splitter to split an input optical signal into the optical network equipment into two similar optical signals;

a first optical switch fabric to couple optical signals from one network connection to another network connection, the first optical switch fabric to receive one of the two similar optical signals and generate a first switched optical signal;

a second optical switch fabric to couple the optical signals from the one network connection to the another network connection, the second optical switch fabric to receive another one of the two similar optical signals and generate a second switched optical signal; and

a switch to receive the first and second switched optical signals and to select between the first switched optical signal and the second switched optical signal as the output optical signal from the optical network equipment.

21. The apparatus of claim 20 wherein

the first optical switch fabric provides one optical path for data signals of the incoming optical signal and the second optical switch fabric provides a redundant optical path for data signals of the incoming optical signal.

22. The apparatus of claim 20 wherein

either one of the first and second switched optical signals is faulty and the other one is selected by the switch as the output optical signal from the optical network equipment.

23. The apparatus of claim 20 wherein

the splitter is a passive splitter.

24. The apparatus of claim 20 wherein

splitter is an optical splitter.

25. The apparatus of claim 20 further comprising

an optical-electrical-optical converter coupled to the splitter, the optical-electrical-optical converter to convert the input optical signal into an electrical signal and the electrical signal into a regenerated optical signal to couple into the splitter as the input optical signal.

26. The apparatus of claim 25 wherein

the electrical signal to provide monitoring of the input optical signal.

27. The apparatus of claim 25 wherein

the optical-electrical-optical converter and the splitter are in an input path of a smart port card of the optical network equipment.

28. The apparatus of claim 20 further comprising

an optical-electrical converter to convert the input optical signal into an electrical signal, and wherein the splitter couples one of the two similar optical signals into the first optical switch fabric and the other one of the two similar optical signals into the second optical switch fabric, the splitter including

a first electrical-optical converter coupled to the optical-electrical converter, the first electrical-optical converter to convert the electrical signal into one of the two similar optical signals, and

a second electrical-optical converter coupled to the optical-electrical converter, the second electrical-optical converter to convert the electrical signal into another one of the two similar optical signals.

29. The apparatus of claim 20 wherein

the switch is a passive switch.

30. The apparatus of claim 20 wherein

the switch is an optical switch.

31. The apparatus of claim 30 further comprising

an optical-electrical-optical converter coupled to the optical switch, the optical-electrical-optical converter to convert the optical output signal into an electrical signal and the electrical signal into an output optical signal to output from the optical network equipment as the optical output signal.

32. The apparatus of claim 31 wherein

the optical-electrical-optical converter and the optical switch are in an output path of a smart port card of the optical network equipment.

33. The apparatus of claim 20 wherein

the switch includes

a first optical-electrical converter to convert the first switched optical signal into a first electrical signal,

a second optical-electrical converter to convert the first switched optical signal into a second electrical signal,

a multiplexer coupled to the first optical-electrical converter to receive the first electrical signal and to the second optical-electrical converter to receive the second electrical signal, the multiplexer to select between the first electrical signal and the second electrical signal as its output electrical signal, and

an electrical-optical converter coupled to the multiplexer to receive the output electrical signal, the electrical-optical converter to convert the output electrical signal into the output optical signal of the optical network equipment, the output electrical signal for monitoring the output optical signal of the optical network equipment.

34. A method of bridging optical signals in an optical cross-connect switch to increase reliability, the method comprising:

receiving an optical signal;

splitting the optical signal into two similar optical signals;

coupling one of the two similar optical signals into a first optical switch fabric and the another one of the two similar optical signals into a second optical switch fabric;

routing the two similar optical signals over optical paths respectively in the first optical switch fabric and the second optical switch fabric to two outputs; and

selecting one of the two similar optical signals at the two outputs as an optical output signal of the optical cross-connect switch.

35. The method of claim 34 wherein

one of the two similar optical signals has failed to reach a respective one of the two outputs and the other of the two outputs is selected by the selecting which has the other of the two similar optical signals present.

36. The method of claim 34 further comprising

prior to the splitting of the optical signal into the two similar optical signals, converting the optical signal into an electrical signal.

37. The method of claim 34 further comprising

converting the optical output signal into an electrical signal for monitoring.

38. The method of claim 37 further comprising

converting the electrical signal into an optical signal to be output as the output optical signal from the optical network equipment.