Optical monitoring for OXC fabric

• US 6,507,421 B1
• Filed: 10/08/1999
• Issued: 01/14/2003
• Est. Priority Date: 10/08/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Guardian Corp. (Broadcom, Inc.), Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Neilson, David Thomas, Bishop, David John, Giles, Randy Clinton
• Primary Examiner(s): Pascal, Leslie
• Assistant Examiner(s): Phan, Hanh
• Application Number:
  US09/414,621
• Time in Patent Office: 1,194 Days
• Field of Search: 359/117, 359/128, 359/110, 359/124, 359/127, 359/130, 359/139, 359/159, 385/17, 385/18, 385/16, 385/24, 385/19, 385/20, 385/21, 385/22, 385/23
• US Class Current: 398/56
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• 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 2011/0083 Testing; Monitoring

Abstract

An optical crossconnect (OXC) fabric including an array of tiltable mirrors, a reflector and a plurality of optical fibers controls the position of the mirrors to optimize the transfer of a signal between an input optical fiber and an output optical fiber by monitoring the optical signal at an optical translation unit in each of the input optical fiber and the output optical fiber. The optical translation units are operable for regenerating the optical signals transmitted through the fibers.

Claims

1. An optical crossconnect device, comprising:

an input fiber;

an output fiber;

an array of tiltable mirrors comprising a plurality of mirrors, each mirror being tiltable about at least one tilting axis for directing a signal received from said input fiber to said output fiber;

a controller operatively connected to said array of tiltable mirrors for positioning said mirror of said array of tiltable mirrors about said at least one tilting axis so that an input signal received from said input fiber is directed toward said output fiber; and

an input buffer connected to said input fiber and an output buffer connected to said output fiber, said controller being connected to said input buffer and to said output buffer for monitoring an input optical signal transmitted from said input fiber to said array of mirrors and for monitoring an output optical signal received by said output fiber from said array of mirrors, and said controller being operatively connected to said array of mirrors for operatively adjusting a position of said mirror of said array of mirrors in response to a monitored difference between said input optical signal in said input buffer and said output optical signal in said output buffer.

2. The device of claim 1, wherein said input buffer comprises an input optical translation unit connected to said input fiber for regenerating an optical signal in said input fiber and said output buffer comprises an output optical translation unit for regenerating an optical signal in said output fiber.

3. The device of claim 2, wherein each of said input optical translation device and said output optical translation device comprises an optical-to-electrical converter for converting an optical signal to an electrical signal, a regeneration unit for receiving the electrical signal and regenerating the electrical signal, and an electrical-to-optical converter to converting the regenerated signal back to an optical signal.

4. The device of claim 3, wherein said controller is connected to said electrical signal in said input optical translation device between said regeneration unit and said electrical-to-optical converter and said controller is connected to said electrical signal in said output optical translation device between said optical-to-electrical converter and said regeneration unit.

5. The device of claim 1, wherein said input fiber comprises an array of input fibers and said output fiber comprises an array of output fibers.

6. The device of claim 1, wherein said array of tiltable mirrors comprises a plurality of tiltable mirrors, each of said tiltable mirrors being rotatable about two relatively perpendicular axes.

7. The device of claim 1, wherein said controller is connected for receiving a routing command and includes means for coarsely adjusting said mirrors of said array of mirrors in response to said routing command and for finely adjusting a position of said mirrors of said array of mirrors in response to the monitored difference between said input optical signal in said input buffer and said output optical signal in said output buffer.

8. The device of claim 1, further comprising a reflector, wherein said tiltable mirrors are positionable so that the input signal received from said input fiber is directed toward said output fiber via said reflector.

9. A method of controlling a mirror position in a optical crossconnect fabric comprising an array of tiltable mirrors, said optical crossconnect fabric receiving a plurality of I/O fibers each including an optical translation unit for regenerating an optical signal, wherein said tiltable mirrors are operable for directing the optical signal from an input one of the plurality of I/O fibers to an output one of the plurality of I/O fibers, said method of controlling a mirror position comprising the steps of:

monitoring a level of an optical signal being transmitted to the array of tiltable mirrors in the optical translation unit from the input one of the plurality of fibers;

monitoring a level of an optical signal directed from the array of tiltable mirrors in the optical translation unit to the output one of the plurality of fibers;

comparing the monitored input optical signal to the monitored output optical signal to calculate a difference between the monitored input optical signal and the monitored output optical signal;

determining whether the calculated difference between the monitored input optical signal and the monitored output optical signal is greater than a predetermined threshold level; and

adjusting the array of mirrors to minimize the calculated difference between the monitored input optical signal and the monitored output optical signal if it is determined in said step of determining that the calculated difference between the monitored input optical signal and the monitored output optical signal is greater than the threshold level.

10. The method of claim 9, wherein the optical translation units each include an optical-to-electrical converter for converting the optical signal into an electrical signal, and wherein each of said steps of monitoring a level of an optical signal from the input one of the plurality of fibers and of monitoring a level of an optical signal directed to the output one of the plurality of fibers includes monitoring the electrical signal in the optical translation units.

11. The method of claim 9, wherein said step of adjusting the array of mirrors comprises coarsely adjusting the array of mirrors in response to an external routing command and finely adjusting said array of mirrors in response to the calculated difference between the monitored input optical signal and the monitored output optical signal.