Methods for performing in-service upgrades of optical wavelength cross connects

• US 6,813,408 B2
• Filed: 03/08/2002
• Issued: 11/02/2004
• Est. Priority Date: 03/08/2002
• Status: Expired due to Fees

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: PTS Corporation
• Inventors: Bortolini, Edward J.
• Primary Examiner(s): Williams, Joseph
• Assistant Examiner(s): Dong, Dalei
• Application Number:
  US10/093,843
• Publication Number:
  US 20030169961A1
• Time in Patent Office: 970 Days
• Field of Search: 385/15-18, 398/48-50, 370/228, 714/4
• US Class Current: 385/17
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• 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 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• CPC Class Codes: H04J 14/0219 Modular or upgradable architectures
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• 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 2011/0043 Fault tolerance
• CPC Class Codes: H04Q 2011/0052 Interconnection of switches

Abstract

Methods are provided for upgrading a K_i1×K_j1 optical wavelength cross connect to a K_i2×K_j2 optical wavelength cross connect without taking the cross connect out of service. Each K_i×K_j cross connects has a working fabric with multiple optical components and has a protection fabric. The working fabric receives optical traffic from K_i input optical signals and transmits K_j output optical signals. The protection fabric is configured to bypass at least one of the optical components in the event of a fault. The upgrade of the K_i1×K_j1 optical wavelength cross connect proceeds by upgrading the protection fabric to accommodate at least K_i2 input optical signals. Sequentially, each of the optical components included on the working fabric is upgraded. The optical traffic received by that optical component is bypassed to the protection fabric. Thereafter, that optical component is upgraded to accommodate at least K_i2 input optical signals. Thereafter, the bypassed optical traffic is returned to that optical component.

Claims

1. A method for performing an in-service upgrade of a K_i1×

K_j1 optical wavelength cross connect to a K_i2×

K_j2 optical wavelength cross connect, each K_i×

K_j optical wavelength cross connect comprising (1) a working fabric having a plurality of optical components, the working fabric configured with a capacity to receive optical traffic from K_i input optical signals and to transmit K_j output optical signals, and (2) a protection fabric having a capacity to accommodate at least K_i1 input optical signals and configured to bypass at least one of the optical components in the event of a fault, the method comprising;

upgrading the protection fabric to increase the capacity of the protection fabric to accommodate at least K_i2 input optical signals; and

sequentially, for each of the optical components included on the working fabric,

bypassing optical traffic received by that optical component to the protection fabric;

thereafter, upgrading that optical component to accommodate at least K_i2 input optical signals; and

thereafter, returning the bypassed optical traffic to that optical component;

wherein K_i2>

K_i1.

2. The method recited in claim 1 wherein upgrading the protection fabric comprises increasing a number of the optical components included on the working fabric that may be bypassed simultaneously.

3. The method recited in claim 1 wherein, before upgrading, the protection fabric is configured to bypass a plurality of the optical components included on the working fabric, the method further comprising bypassing additional optical traffic to the protection fabric in response to a fault.

4. The method recited in claim 1 wherein at least one of the optical components included on the working fabric comprises a wavelength routing element adapted for selectively routing wavelength components between a first optical signal and a plurality of second optical signals according to a configurable state of such wavelength routing element.

5. The method recited in claim 4 wherein the wavelength routing element comprises a four-pass wavelength routing element.

6. The method recited in claim 4 wherein the wavelength routing element comprises a two-pass wavelength routing element.

7. The method recited in claim 1 wherein the protection fabric comprises a wavelength routing element adapted for selectively routing wavelength components between a first optical signal and a plurality of second optical signals according to a configurable state of such wavelength routing element.

8. The method recited in claim 7 wherein the wavelength routing element comprises a four-pass wavelength routing element.

9. The method recited in claim 7 wherein the wavelength routing element comprises a two-pass wavelength routing element.

10. The method recited in claim 1 further comprising adding additional optical components to the working fabric to accommodate K_j2−

K_j1 additional output optical signals.

11. The method recited in claim 1 wherein the K_i×

K_j optical wavelength cross connect further comprises a plurality of optical splitters configured to direct an equivalent to each of the input optical signals either to at least one of the optical components included on the working fabric or to the protection fabric, the method further comprising increasing a splitting capacity of each of the optical splitters.

12. The method recited in claim 11 wherein each of the optical splitters is configured to direct equivalents to all of the optical components included on the working fabric.

13. The method recited in claim 11 wherein increasing the splitting capacity of each of the optical splitters comprises adding a further optical splitter to an output of such each of the optical splitters corresponding to a bypassed optical component while that optical component is bypassed.

14. The method recited in claim 1 wherein K_i2=2K_i1.

15. The method recited in claim 1 wherein K_i1=K_j1 and K_i2=K_j2.

16. A method for performing an in-service upgrade of a K_i1×

K_j1 optical wavelength cross connect to a K_i2×

K_j2 optical wavelength cross connect, each K_i×

K_j optical wavelength cross connect comprising (1) a working fabric having K_j wavelength routing elements, each adapted for selectively routing wavelength components from K_i equivalent input optical signals to a corresponding output optical signal according to a configurable state of such wavelength routing element, and configured on the working fabric to receive the K_i equivalent input optical signals from K_i input optical signals transmitted through a plurality K_i of optical splitters, and (2) a protection fabric having a capacity configured to accommodate at least K_i1 input optical signals and configured to bypass at least one of the wavelength routing elements in the event of a fault, the method comprising;

adding K_j2−

K_j1 wavelength routing elements, each additional wavelength routing element being adapted for routing spectral bands from K_j2 equivalent input optical signals to a corresponding output signal;

upgrading the protection fabric to increase the capacity of the protection fabric to accommodate at least K_i2 input optical signals; and

sequentially, for each of the K_j1 wavelength routing elements initially included on the working fabric,

bypassing optical traffic received by that wavelength routing element to the protection fabric;

thereafter, upgrading that wavelength routing element to receive K_i2 equivalent input optical signals and adding a further optical splitter to each optical-splitter output connected with that wavelength routing element; and

thereafter, returning the bypassed optical traffic to that wavelength routing element;

wherein K_i2>

K_i1.

17. The method recited in claim 16 wherein upgrading the protection fabric comprises increasing a number of the wavelength routing elements included on the working fabric that may be bypassed simultaneously.

18. The method recited in claim 16 wherein, before upgrading, the protection fabric is configured to bypass a plurality of the wavelength routing elements included on the working fabric, the method further comprising bypassing additional optical traffic to the protection fabric in response to a fault.

19. The method recited in claim 16 wherein K_i=K_j1 and K_i2=K_j2.