Optical switch and method for aligning optical switch components

• US 6,529,652 B1
• Filed: 03/15/2001
• Issued: 03/04/2003
• Est. Priority Date: 03/15/2001
• Status: Expired due to Fees

• Current Assignee: Rembrandt Communications LP (Rembrandt IP Management, LLC)
• Original Assignee: Tellium, Inc. (DZS, Inc.)
• Inventors: Brener, Igal
• Primary Examiner(s): Palmer, Phan T. H.
• Application Number:
  US09/754,254
• Time in Patent Office: 719 Days
• Field of Search: 385/16-24, 385/25, 385/31, 359/291, 359/224, 359/223, 359/292
• US Class Current: 385/16
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• 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 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3586 Control or adjustment details, e.g. calibrating testing optical equipment G01M11/00
• CPC Class Codes: G02B 6/359 of the position of the moving element itself during switching, i.e. without monitoring the switched beams

Abstract

An optical switch having a fiber/lens array and a switching substrate may be properly aligned using one or more static mirrors or photodetectors provided on the switching substrate. The static mirrors may be designed to reflect incident light back into an input fiber, where the back reflected light may be detected, or to a detector provided at a predetermined position. Accordingly, the position of the switching substrate and/or fiber/lens array may be adjusted until reflected light having predetermined power is detected. In another embodiment, the position of the switching substrate and/or fiber/lens array may be adjusted until predetermined power is detected by the photodetectors provided on the switching substrate.

Claims

1. An optical switch comprising:

an input optical array comprising input optical fibers and micro-lenses optically aligned with the input optical fibers;

an output optical array comprising output optical fibers and micro-lenses optically aligned with the output optical fibers;

an optical switching mechanism for selectively coupling input optical signals from the input optical fibers to selected output optical fibers, said optical switching mechanism including a first switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the input optical array, said static alignment micro-mirror of the first substrate provided at an angle α

1 relative to the surface of the first substrate so as to reflect the optical signal carried by an input optical fiber back into the input optical fiber, and a second switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the output optical array, said static alignment micro-mirror of the second substrate provided at an angle α

2 relative to the surface of the second substrate so as to reflect the optical signal carried by an output optical fiber back into the output optical fiber.

2. The optical switch according to claim 1, wherein each input optical fiber is integrated with a corresponding one of the micro-lenses.

3. An optical switch comprising:

an input optical array comprising input optical fibers and micro-lenses optically aligned with the input optical fibers;

an output optical array comprising output optical fibers and micro-lenses optically aligned with the output optical fibers;

an optical switching mechanism for selectively coupling input optical signals from the input optical fibers to selected output optical fibers, said optical switching mechanism including a first switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the input optical array, said static alignment micro-mirror of the first substrate provided at an angle α

1 relative to the surface of the first substrate so as to reflect the optical signal carried by an input optical fiber back into the input optical fiber, and a second switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the output optical array, said static alignment micro-mirror of the second substrate provided at an angle α

2 relative to the surface of the second substrate so as to reflect the optical signal carried by an output optical fiber back into the output optical fiber; and

a plurality of photodetectors coupled to a first group of the optical input fibers, said photodetectors for detecting the power of the optical signal back-reflected into the first group of optical input fibers by said static alignment micro-mirrors of the first switching substrate.

4. The optical switch according to claim 3, further comprising at least one light source coupled to the first group of the input optical fibers, said light source generating optical signals of a predetermined wavelength detectable by said photodetectors and propagating the optical signals of the predetermined wavelength.

5. The optical switch according to claim 4, wherein said predetermined wavelength differs from a wavelength of optical signals directed to the movable micro-mirrors by a second group of input optical fibers different from the first group.

6. An optical switch comprising:

an input optical array comprising input optical fibers and micro-lenses optically aligned with the input optical fibers;

an output optical array comprising output optical fibers and micro-lenses optically aligned with the output optical fibers;

an optical switching mechanism for selectively coupling input optical signals from the input optical fibers to selected output optical fibers, said optical switching mechanism including a first switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the input optical array, said static alignment micro-mirror of the first substrate provided at an angle α

1 relative to the surface of the first substrate so as to reflect the optical signal carried by an input optical fiber back into the input optical fiber, and a second switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the output optical array, said static alignment micro-mirror of the second substrate provided at an angle α

2 relative to the surface of the second substrate so as to reflect the optical signal carried by an output optical fiber back into the output optical fiber; and

a plurality of photodetectors coupled to a first group of the optical output fibers, said photodetectors for detecting the power of light back-reflected into the first group of optical output fibers by the static alignment micro-mirrors of the second switching substrate.

7. An optical switch comprising:

an input optical array comprising input optical fibers and micro-lenses optically aligned with the input optical fibers;

an output optical array comprising output optical fibers and micro-lenses optically aligned with the output optical fibers;

an optical switching mechanism for selectively coupling input optical signals from the input optical fibers to selected output optical fibers, said optical switching mechanism including a switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the output optical array, said static alignment micro-mirror of the second substrate provided at an angle α

relative to the surface of the second substrate so as to reflect the optical signal carried by an output optical fiber back into the output optical fiber.

8. The optical switch according to claim 7, wherein each output optical fiber is integrated with a corresponding one of the micro-lenses.

9. An optical switch comprising:

an input optical array comprising input optical fibers and micro-lenses optically aligned with the input optical fibers;

an output optical array comprising output optical fibers and micro-lenses optically aligned with the output optical fibers;

an optical switching mechanism for selectively coupling input optical signals from the input optical fibers to selected output optical fibers, said optical switching mechanism including a switching substrate having a plurality of movable micro-mirrors and at least one static alignment micro-mirror on a surface thereof facing the output optical array, said static alignment micro-mirror of the second substrate provided at an angle α

relative to the surface of the second substrate so as to reflect the optical signal carried by an output optical fiber back into the output optical fiber; and

a plurality of photodetectors coupled to a first group of the optical output fibers, said photodetectors for detecting the power of light back-reflected into the first group of optical output fibers by said static alignment micro-mirrors of the first switching substrate.

10. The optical switch according to claim 9, further comprising at least one light source, said light source generating optical signals of a predetermined wavelength detectable by said photodetectors.

11. The optical switch according to claim 10, wherein said predetermined wavelength differs from a wavelength of optical signals directed to the movable micro-mirrors.

12. A combination for an optical switch comprising:

an optical array comprising optical fibers and micro-lenses optically aligned with the optical fibers; and

a switching substrate having a plurality of movable micro-mirrors and static alignment micro-mirrors on a surface thereof facing the optical array, wherein each of said static alignment micro-mirrors is provided at an angle α

relative to the surface of the substrate so as to reflect an optical signal carried by an optical fiber back into the input optical fiber and each of said movable micro-mirrors for reflecting optical signals carried by the optical fibers at a selectable angle away from the optical array.

13. The combination according to claim 12, wherein the movable micro-mirrors and static alignment micro-mirrors are provided in an array on the surface of the switching substrate.

14. The combination according to claim 13, wherein the array is rectangular and the static alignment micro-mirrors are provided at least at the corners of the array.

15. The combination according to claim 12, wherein each optical fiber is integrated with a corresponding one of the micro-lenses.

16. The combination according to claim 12, wherein said predetermined wavelength differs from a wavelength of optical signals directed to the movable micro-mirrors by a second group of the optical fibers different from the first group.

17. The combination according to claim 12, wherein the switching substrate comprises a microelectromechanical system (MEMS) chip.

18. A combination for an optical switch comprising:

an optical array comprising optical fibers and micro-lenses optically aligned with the optical fibers; and

a switching substrate having a plurality of movable micro-mirrors and static alignment micro-mirrors on a surface thereof facing the optical array, wherein each of said static alignment micro-mirrors is provided at an angle α

relative to the surface of the substrate so as to reflect an optical signal carried by an optical fiber back into the input optical fiber and each of said movable micro-mirrors for reflecting optical signals carried by the optical fibers at a selectable angle away from the optical array; and

a plurality of photodetectors coupled to a first group of the optical fibers, said photodetectors for detecting the power of light back-reflected into the first group of optical fibers by said static alignment micro-mirrors of the first switching substrate.

19. The combination according to claim 18, further comprising at least one light source coupled to the first group of optical fibers, said light source generating optical signals of a predetermined wavelength detectable by said photodetectors.

20. A method of aligning components of an optical switch comprising an optical array including optical fibers and micro-lenses optically aligned with the optical fibers and a switching substrate having a plurality of movable micro-mirrors and static alignment micro-mirrors on a surface thereof facing the optical array, each said static alignment micro-mirror provided at an angle α

relative to the surface of the substrate, the method comprising;

detecting the power of back-reflected optical signals in the plurality of optical fibers; and

moving at least one of the optical array and the switching substrate until the detected power in the plurality of optical fibers reaches a predetermined value.

21. An optical switch comprising:

an input optical array comprising input optical fibers and micro-lenses optically aligned with the input optical fibers;

an output optical array comprising output optical fibers and micro-lenses optically aligned with the output optical fibers;

an optical switching mechanism for selectively coupling optical signals from the input optical fibers to selected output optical fibers, said optical switching mechanism including a first switching substrate having a plurality of movable micro-mirrors and at least photodetector on a surface thereof facing the input optical array, wherein said photodetector is positioned to detect the optical signals carried by an input optical fiber, and a second switching substrate having a plurality of movable micro-mirrors and at least one photodetector on a surface thereof facing the output optical array, the photodetector positioned to detect the optical signals carried by an output optical fiber.

22. The optical switch according to claim 21, wherein each of the first and second switching substrates include multiple photodetectors, the photodetectors and movable micro-mirrors provided in an array.

23. The optical switch according to claim 22, wherein the arrays are rectangular and the photodetectors are provided at least at the corners of the arrays.

24. The optical switch according to claim 21, further comprising at least one light source, said light source generating optical signals of a predetermined wavelength detectable by said photodetectors.

25. The optical switch according to claim 21, wherein said predetermined wavelength differs from a wavelength of optical signals directed to the movable micro-mirrors.

26. The optical switch according to claim 21, wherein the first and second switching substrates comprise microelectromechanical system (MEMS) chips.

27. The combination according to claim 21, further comprising at least one static micro-mirrors provided on the surface of the switching substrate.

28. The combination according to claim 21, wherein the switching substrate comprises a microelectromechanical system (MEMS) chip.

29. A combination for an optical switch comprising:

an optical array comprising optical fibers and micro-lenses optically aligned with the optical fibers; and

a switching substrate having a plurality of movable micro-mirrors and a plurality of photodetectors on a surface thereof facing the optical array, the micro-mirrors and the photodetectors provided in an array so that each micro-mirror and photodetector corresponds to a micro-lens of the optical array.

30. The combination according to claim 29, further comprising at least one light source coupled to a first group of said optical fibers, said light source generating optical signals of a predetermined wavelength detectable by said photodetectors.

31. The combination according to claim 30, wherein said predetermined wavelength differs from a wavelength of optical signals directed to the movable micro-mirrors and carried by a second group of optical fibers different from the first group.

32. A method of aligning components of an optical switch comprising an optical array including optical fibers and micro-lenses optically aligned with the optical fibers and a switching substrate having a plurality of movable micro-mirrors and a plurality of photodetectors arranged in an array so that each micro-mirror and each photodetector corresponds to a micro-lens of the optical array, the method comprising:

transmitting light of a predetermined wavelength in the optical fibers optically aligned with the micro-lenses corresponding to the plurality of photodetectors;

detecting the power of optical signals detected by said photodetectors; and

moving at least one of the optical array and the switching substrate until the detected power reaches a predetermined value.

33. A method of aligning components of an optical switch comprising an optical array including optical fibers and micro-lenses optically aligned with the optical fibers and a switching substrate having a plurality of movable micro-mirrors and static alignment micro-mirrors on a surface thereof facing the optical array, each said static alignment micro-mirror provided at an angle α

relative to the surface of the substrate, the method comprising;

positioning at least one optical detector at a desired position relative to one of the optical array and the switching substrate;

directing optical signals from the optical fibers to the static alignment micro-mirrors;

detecting optical signals reflected by the static alignment micro-mirrors using the detector; and

moving the other of the optical array and the switching substrate until the detected power reaches a predetermined value.