Detunable Fabry-Perot interferometer and an add/drop multiplexer using the same

• US 20030123125A1
• Filed: 12/31/2002
• Published: 07/03/2003
• Est. Priority Date: 03/20/2000
• Status: Active Grant

• Current Assignee: NP Photonics Incorporated
• Original Assignee: NP Photonics Incorporated
• Inventors: Little, Michael J.
• Granted Patent: US 6,747,775 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 99/008 separating the processed structure from a mother substrate
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/29358 Multiple beam interferometer external to a light guide, e.g. Fabry-Pérot, etalon, VIPA plate, OTDL plate, continuous interferometer, parallel plate resonator G02B6/29347, G02B6/29349, G02B6/2935, G02B6/29361 take precedence; resonator evanescently coupled to light guide G02B6/29335
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• 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 6/362 Vacuum holders for optical elements
• CPC Class Codes: G02B 6/3692 with surface micromachining involving etching, e.g. wet or dry etching steps surface micromachining involving subtractive techniques B81C1/00055
• CPC Class Codes: G02B 6/4226 Positioning means for moving the elements into alignment, e.g. alignment screws, deformation of the mount
• CPC Class Codes: H04J 14/00 Optical multiplex systems

Abstract

A detunable Fabry-Perot interferometer, and method of tuning a Fabry-Perot interferometer are provided. The Fabry-Perot interferometer includes a first mirror, a second mirror oriented with respect to tie first mirror so as to define a Fabry-Perot cavity therebetween, and an actuator configured to adjust a resonant wavelength of the Fabry-Perot cavity by varying a gap between the first and second mirrors, wherein the actuator is configured to selectively maintain the first and second mirrors in a substantially non-parallel relationship while the resonant wavelength of the Fabry-Perot interferometer is varied. The detunable Fabry-Perot interferometer can be employed in a multiplexer of a telecommunications system, as provided.

Claims

1. A Fabry-Perot interferometer, comprising:

a first mirror;

a second mirror oriented with respect to tie first mirror so as to define a Fabry-Perot cavity therebetween; and

an actuator configured to adjust a resonant wavelength of the Fabry-Perot cavity by varying a gap between the first and second mirrors, wherein the actuator is configured to selectively maintain the first and second mirrors in a substantially non-parallel relationship while the resonant wavelength of the Fabry-Perot interferometer is varied.

2. The Fabry-Perot interferometer according to claim 1, wherein, when the actuator maintains the first and second mirror in a substantially parallel relationship with respect to one another, the Fabry-Perot interferometer passes a predetermined wavelength of light therethrough, and when the actuator maintains the first and second mirrors in a substantially non-parallel relationship with respect to one another, the Fabry-Perot interferometer reflects substantially wavelengths of light.

3. The Fabry-Perot interferometer according to claim 1, wherein the first mirror is fixed, and the second mirror is movable by the actuator to adjust the gap between the first and second mirrors.

4. The Fabry-Perot interferometer according to claim 1, wherein the first and second mirrors are partially reflective.

5. The Fabry-Perot interferometer according to claim 1, wherein the fltst mirror is affixed to a mirror support.

7. The Fabry-Perot interferometer according to claim 5, wherein the mirror support has an anti-reflective coating on a surface opposite to a surface to which the first n±

ror is affixed.

8. The Fabry-Perot interferometer according to claim 1, wherein the second mirror is affixed to a compliant optical support, and portion of the compliant optical support is substantially flexible.

9. The Fabry-Perot interferometer according to claim 1, wherein the second mirror is affixed to a compliant optical support, wherein at least a portion of the compliant optical support comprises silicon, and another portion of the compliant optical support comprises a compliant material.

10. The Fabry-Perot interferometer according to claim 9, wherein the compliant material comprises a elastomer.

11. The Fabry-Perot interferometer according to claim 1, wherein the second mirror is affixed to a compliant optical support is movable by the actuator.

12. The Fabry-Perot interferometer according to claim 10, wherein the compliant optical support comprises:

an island, to which the second mirror is affixed; and

a frame, wherein the island and the frame are flexibly joined by a complaint member.

13. The Fabry-Perot interferometer according to claim 12, wherein at least a portion of the actuator is attached to the island.

14. The Fabry-Perot interferometer according to claim 12, wherein the compliant member comprises an elastomer.

15. The Fabry-Perot interferometer according to claim 12, wherein the island and the frame comprise silicon.

16. The Fabry-Perot interferometer according to claim 12, wherein the actuator comprises:

a plurality of electrodes positioned on a surface of the island opposite a surface to which the second mirror is attached; and

an electrode disposed on an actuator support.

17. The Fabry-Perot interferometer according to claim 16, wherein the actuator support comprises silicon.

18. The Fabry-Perot interferometer according to claim 16, further comprising an anti-reflective coating formed the surface of the island where the fttst plurality of electrodes are formed.

19. A wavelength-division-multiplexer system comprising the Fabry-Perot interferometer of claim 1.

6. The Fabry-Perot interferometer according to claimS, wherein the mirror support comprises silicon.

20. A Fabry-Perot interferometer, comprising:

a first mirror;

a second mirror oriented with respect to the first mirror so as to define a Fabry-Perot cavity therebetween; and

an actuator configured to tune a resonant wavelength of the Fabry-Perot cavity between a first wavelength and a second wavelength by varying a gap between the first and second mirrors, wherein the actuator controls the relationship between the first and second mirrors to suppress transmission of intervening resonant wavelengths while the resonant wavelength of the Fabry-Perot cavity is tuned from the first wavelength to the second wavelength.

21. The Fabry-Perot interferometer of claim 20, wherein the actuator controls a tilt of the first or second mirror to suppress the transmission of intervening wavelengths.

22. A multiplexer for a telecommunications system, comprising:

an input pathway though which a main optical signal is input into the multiplexer;

an output pathway though which a main optical signal is output from the multiplexer;

an add pathway though which an optical channel is added to the main optical signal;

a drop pathway though which an optical channel is removed from the main optical signal;

an auxiliary pathway containing a tunable Fabry-Perot interferometer;

a first circulator joining the auxiliary pathway to the input pathway and the output pathway; and

a second circulator joining the auxiliary pathway to the add pathway and the drop pathway, wherein the Fabry-Perot interferometer comprises;

a first mirror;

a second mirror oriented with respect to the first mirror so as to define a Fabry-Perot cavity therebetween; and

an actuator configured to adjust a resonant wavelength of the Fabry-Perot cavity by varying a gap between the first and second mirrors, wherein the actuator is configured to selectively maintain the first and second mirror in a substantially non-parallel relationship while the resonant wavelength of the Fabry-Perot interferometer is varied.

23. A method of tuning a Fabry-Perot interferometer between a first resonant wavelength and a second resonant wavelengths, comprising:

suppressing transmission of resonant wavelengths that lie between the first and second resonant wavelengths while adjusting a gap between the first and second Fabry-Perot cavity mirrors to tune between the first and second resonant wavelengths.

24. The method of tuning a Fabry-Perot interferometer according to claim 23, wherein the resonant wavelengths that lie between the first and second wavelengths are suppressed by tilting the first or second Fabry-Perot mirror with respect to the other.

25. The method of tuning a Fabry-Perot interferometer according to claim 24, wherein the first and second mirror are oriented so as to be substantially parallel to one another after the Fabry-Perot interferometer is tuned from the first resonant wavelength to the second resonant wavelength.

26. The method of tuning a Fabry-Perot interferometer according to claim 23, wherein the step of adjusting the gap between the first and second Fabry-Perot cavity mirrors comprises maintaining the first Fabry-Perot cavity mirror in a fixed position and moving the second Fabry-Perot cavity mirror.