Optical switch fabric with redundancy

• US 7,248,760 B1
• Filed: 03/15/2005
• Issued: 07/24/2007
• Est. Priority Date: 06/06/2001
• Status: Expired due to Term

• Current Assignee: Calient Networks Incorporated
• Original Assignee: Calient Networks Incorporated
• Inventors: Corbalis, Charles Matthew, Fant, Walt Joseph, Helkey, Roger Jonathan
• Primary Examiner(s): HYEON, HAE M
• Application Number:
  US11/081,265
• Time in Patent Office: 861 Days
• Field of Search: 385/16, 385/17
• US Class Current: 385/16
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0043 Fault tolerance
• CPC Class Codes: H04Q 2011/0052 Interconnection of switches
• CPC Class Codes: H04Q 2011/0056 Clos
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring

Abstract

An optical switch fabric with an input stage, an output stage, and a center stage coupled in a cascaded manner. The center stage includes (1) a minimum number of center switches greater than one that cause the optical switch fabric to be strict-sense nonblocking and (2) at least one additional center switch to provide redundancy for the optical switch fabric. A module is described that includes optical input and output switches coupled to an optical center stage of an optical switch fabric. The module includes an interior cavity that contains free space beams from both the optical input switch and the optical output switch. A method is described for reconfiguring a redundant optical switch into a multilevel optical switch without interrupting operation of the signals carried by the optical switch by adding additional switch components and reconfiguring the fiber interconnection between switch elements.

Claims

1. A method for reconfiguring an optical switch without interrupting working optical signals, comprising:

initially routing working optical signals between input and output stages of the optical switch through a choice of first and second sets of fiber lines via a first center stage switch and third and fourth sets of fiber lines via a second center stage switch;

rerouting any working optical signals from the third and fourth sets of fiber lines to the first and second sets of fiber lines;

moving the fourth set of fiber lines from the second center stage switch to a third center stage switch;

rerouting any working optical signals from the second set of fiber lines to the fourth set of fiber lines; and

moving the second set of fiber lines from the first center stage switch to a fourth center stage switch.

2. The method of claim 1, further comprising rerouting the working optical signals through a choice of first, second, third, and fourth sets of fiber lines via respective first, fourth, second, and third center stage switches.

3. The method of claim 2, further comprising:

adding one or more additional switches to the input stage;

adding one or more additional switches to the output stage;

connecting additional fiber lines to the additional switches in the input and output stages to provide optical signal paths between the additional switches in the input and output stages via the first, second, third, and fourth center stage switches.

4. A method for reconfiguring an optical switch without interrupting working optical signals, comprising:

initially routing working optical signals between input and output stages of the optical switch through a choice of first, second, third, and fourth sets of fiber lines via respective first, second, third, and fourth center stage switches;

rerouting any working optical signals from the fourth set of fiber lines to the first set of fiber lines;

moving the fourth set of fiber lines from the fourth center stage switch to the first center stage switch;

rerouting any working optical signals from the third set of fiber lines to the fourth set of fiber lines;

moving the third set of fiber lines from the third center stage switch to the second center stage switch;

rerouting the working optical signals through a choice of first and fourth sets of fiber lines via the first center stage switch and second and third sets of fiber lines via the second center stage switch.

5. The method of claim 4, further comprising:

removing the third and fourth center stage switches from the optical switch;

removing fiber lines connected to the third and fourth center stage switches.