Temperature control of micro-mirrors of an optical switch substrate

• US 6,633,693 B1
• Filed: 03/27/2001
• Issued: 10/14/2003
• Est. Priority Date: 03/27/2001
• Status: Expired due to Fees

• Current Assignee: Rembrandt Communications LP (Rembrandt IP Management, LLC)
• Original Assignee: Tellium, Inc. (DZS, Inc.)
• Inventors: Lin, Lih, Framski, Walter, Peale, David R.
• Primary Examiner(s): Duverne, Jean F.
• Application Number:
  US09/817,238
• Time in Patent Office: 931 Days
• Field of Search: 385/18, 385/16, 385/17, 385/19, 385/20, 385/25, 385/31, 385/33, 385/93, 385/15, 385/40, 359/290, 359/627, 359/291, 359/618
• US Class Current: 385/18
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation

Abstract

A temperature control system is provided for an optical switch including steerable micro-mirrors. The system includes at least one sensor and associated sensing circuitry for measuring the temperature of a micro-mirror or a region of a substrate near a micro-mirror. The system also includes a controller that responds to a signal provided by the sensing circuitry. The controller response may include activating heating or cooling devices the region that is sensed to adjust the temperature of the region.

Claims

1. A temperature control system for one or more micro-mirrors of an optical device, comprising:

a temperature sensor located adjacent a micro-mirror of an optical device, wherein the temperature sensor senses the temperature near the micro-mirror and generates a temperature signal indicative of the sensed temperature;

a thermal element located adjacent the micro-mirror and that adjusts the temperature near the micro-mirror; and

a temperature controller that compares the temperature signal to a signal indicative of a desired temperature and generates control signals based on the comparison for controlling the thermal element to adjust the temperature adjacent the micro-mirror until the temperature near the micro-mirror corresponds to the desired temperature.

2. The temperature control system according to claim 1, wherein said temperature sensor is located on the micro-mirror.

3. The temperature control system according to claim 1, wherein said thermal element is located on the micro-mirror.

4. The temperature control system according to claim 1, wherein the temperature sensor and thermal element are formed on a MEMS-based optical switching substrate.

5. The temperature control system according to claim 1, wherein the thermal element comprises a heating element.

6. The temperature control system according to claim 5, wherein the heating element comprises a resistor.

7. The temperature control system according to claim 1, wherein the thermal element comprises a cooling element.

8. The temperature control system according to claim 7, wherein the cooling element comprises a thermoelectric cooler.

9. The temperature control system according to claim 1, wherein the thermal element is a heating and cooling element.

10. An optical switching substrate comprising:

a substrate;

a plurality of micro-mirrors formed on the substrate and tiltable relative to the substrate about first and second axes;

a temperature sensor located on the substrate adjacent at least one of the micro-mirrors, wherein the temperature sensor senses the temperature near the at least one micro-mirror and generates a temperature signal indicative of the sensed temperature;

a thermal element located on the substrate and in thermal contact with the at least one micro-mirror and that adjusts the temperature near the at least one micro-mirror; and

a temperature controller that receives the temperature signal and generates control signals for controlling the thermal element to adjust the temperature adjacent the micro-mirror until the temperature near the micro-mirror corresponds to a desired temperature.

11. The optical switching substrate according to claim 10, wherein said temperature sensor is located on the micro-mirror.

12. The optical switching substrate according to claim 10, wherein said temperature sensor is located on said substrate between at least two of the micro-mirrors.

13. The optical switching substrate according to claim 10, wherein the thermal element is located between at least two of the micro-mirrors.

14. The optical switching substrate according to claim 10, further comprising a plurality of thermal elements distributed over a surface of the substrate between the micro-mirrors.

15. The optical switching substrate according to claim 10, further comprises a plurality of temperature sensors and a plurality of thermal elements, wherein at least one of the temperature sensors and at least one of the thermal elements is provided for each of the micro-mirrors.

16. The optical switching substrate according to claim 10, further comprises a plurality of temperature sensors and a plurality of thermal elements, wherein at least one of the temperature sensors and at least one of the thermal elements is provided for a mirror group comprising a plurality of the micro-mirrors.

17. The optical switching substrate according to claim 10, wherein the thermal element comprises a resistor for heating the substrate responsive to the control signals.

18. The optical switching substrate according to claim 10, wherein the thermal element comprises a thermoelectric cooler for cooling the substrate.

19. The optical switching substrate according to claim 10, wherein the thermal element is a heating and cooling element.

20. An optical switch for selectively coupling optical signals on plurality of optical inputs to selected optical outputs, comprising:

a switching substrate;

a plurality of micro-mirrors formed on the substrate and tiltable relative to the substrate about first and second axes, wherein said micro-mirrors reflect the optical signals in optical paths between the optical inputs and optical outputs;

a temperature sensor located on the substrate adjacent at least one of the micro-mirrors, wherein the temperature sensor senses the temperature near the at least one micro-mirror and generates a temperature signal indicative of the sensed temperature;

a thermal element located on the substrate adjacent the at least one micro-mirror and that adjusts the temperature near the at least one micro-mirror; and

a temperature controller that receives the temperature signal and generates control signals for controlling the thermal element to adjust the temperature adjacent the micro-mirror until the temperature near the micro-mirror corresponds to a desired temperature.

21. The optical switch according to claim 20, wherein said temperature sensor is located on the micro-mirror.

22. The optical switch according to claim 20, wherein said temperature sensor is located on said substrate between at least two of the micro-mirrors.

23. The optical switch according to claim 20, wherein the thermal element is located between at least two of the micro-mirrors.

24. The optical switch according to claim 20, further comprising a plurality of thermal elements distributed over a surface of the substrate between the micro-mirrors.

25. The optical switch according to claim 20, further comprises a plurality of temperature sensors and a plurality of thermal elements, wherein at least one of the temperature sensors and at least one of the thermal elements is provided for each of the micro-mirrors.

26. The optical switch according to claim 20, further comprises a plurality of temperature sensors and a plurality of thermal elements, wherein at least one of the temperature sensors and at least one of the thermal elements is provided for a mirror group comprising a plurality of the micro-mirrors.

27. The optical switch according to claim 20, wherein the thermal element comprises a resistor for heating the substrate responsive to the control signals.

28. The optical switch according to claim 20, wherein the thermal element comprises a thermoelectric cooler for cooling the substrate.

29. The optical switch according to claim 20, wherein the thermal element is a heating and cooling element.