Mirror drift compensation in an optical circuit switch

• US 9,063,295 B2
• Filed: 08/05/2013
• Issued: 06/23/2015
• Est. Priority Date: 08/05/2013
• Status: Active Grant

• Current Assignee: CALIENT Technologies, Inc.
• Original Assignee: CALIENT Technologies, Inc.
• Inventors: Miglani, Jitender, Deacon, Mike, Thattai, Vijayan, Sagaram, Sushma
• Primary Examiner(s): Liu, Li
• Application Number:
  US13/958,889
• Publication Number:
  US 20150036973A1
• Time in Patent Office: 687 Days
• Field of Search: 398 45- 51, 385 16- 18, 359/221.2
• US Class Current: 1/1
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 6/26 Optical coupling means G02B6/36, G02B6/42 take precedence
• CPC Class Codes: G02B 6/35 having switching means by changing the optical properties of the medium G02F1/00
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3588 of the processed beams, i.e. controlling during switching of orientation, alignment, or beam propagation properties such as intensity, size or shape
• CPC Class Codes: G02B 6/359 of the position of the moving element itself during switching, i.e. without monitoring the switched beams
• CPC Class Codes: H04J 14/00 Optical multiplex systems
• CPC Class Codes: H04Q 11/0003 Details
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0039 Electrical control

Abstract

Methods of operating an optical circuit switch and optical circuit switches are disclosed. To make a connection between a first port and a second port, baseline voltages may be determined, baseline voltages being voltages that, if respectively applied to one or more electrode coupled to a first mirror element uniquely associated with the first port and one or more electrode coupled to a second mirror element uniquely associated with the second port, cause the first and second mirror elements to rotate to make the connection in the absence of accumulated mirror element drift. Accumulated drift data associated with one or both of the first mirror element and the second mirror element may be retrieved from a memory. One or more of the baseline voltages may be modified based on the accumulated drift data to provide corrected voltages, and the corrected voltages may be applied to the electrodes.

Claims

1. A method for making a connection from a first port to a second port through an optical circuit switch, comprising:

determining baseline voltages that, if respectively applied to one or more electrode coupled to a first mirror element uniquely associated with the first port and one or more electrode coupled to a second mirror element uniquely associated with the second port, cause the first and second minor elements to rotate to make the connection in the absence of accumulated minor element drift;

retrieving, from a memory, accumulated drift data associated with one or both of the first minor element and the second mirror element;

modifying one or more of the baseline voltages based on the accumulated drift data to provide corrected voltages;

applying the corrected voltages to the electrodes;

receiving a break command to break the connection between the first port and the second port;

applying at-rest voltages to the electrodes; and

periodically decaying the accumulated drift data associated with one or both of the first and second mirror elements in accordance with a predetermined decay function.

2. The method of claim 1, further comprising:

periodically adjusting the voltages applied to the electrodes to minimize an insertion loss of the connection; and

periodically updating the accumulated drift data associated with one or both of the first and second mirror elements based on differences between the adjusted voltages applied to the electrodes and the respective baseline voltages.

3. The method of claim 1, wherein the decay function is linear.

4. The method of claim 1, wherein the decay function is exponential.

5. The method of claim 1, wherein the decay function is stored in a lookup table.

6. The method of claim 1, wherein the accumulated drift data comprises differences between the adjusted voltages applied to the electrodes and the respective baseline voltages.

7. An optical circuit switch, comprising:

a first port;

a second port;

a controller configured to;

determine baseline voltages that, if respectively applied to one or more electrode coupled to a first mirror element uniquely associated with the first port and one or more electrode coupled to a second mirror element uniquely associated with the second port, cause the first and second minor elements to rotate to make a connection from the first port to the second port in the absence of accumulated minor element drift;

modify one or more of the baseline voltages based on stored accumulated drift data associated with one or both of the first and second minor elements to provide corrected voltages;

cause the corrected voltages to be applied to the electrodes to make the connection from the first port to the second port;

receive a break command to break the connection between the first port and the second port;

cause respective at-rest voltages to be applied to the electrodes; and

periodically decay the accumulated drift data associated with one or both of the first and second mirror elements in accordance with a predetermined decay function.

8. The optical circuit switch of claim 7, wherein the controller is further configured to:

periodically adjust the voltages applied to the electrodes to minimize an insertion loss of the connection; and

periodically update the stored accumulated drift data associated with one or both of the first and second mirror elements based on differences between the adjusted voltages applied to the electrodes and the respective baseline voltages.

9. The optical circuit switch of claim 7, wherein the decay function is linear.

10. The optical circuit switch of claim 7, wherein the decay function is exponential.

11. The optical circuit switch of claim 7, wherein the decay function is stored in a lookup table.

12. The optical circuit switch of claim 7, wherein the accumulated drift data comprises differences between the adjusted voltages applied to the electrodes and the respective baseline voltages.