Freespace tunable optoelectronic device and method

• US 20040071180A1
• Filed: 06/17/2003
• Published: 04/15/2004
• Est. Priority Date: 10/09/2002
• Status: Active Grant

• Current Assignee: API Technologies Corporation
• Original Assignee: NanoOpto (API Technologies Corporation)
• Inventors: Wang, Jian
• Granted Patent: US 7,013,064 B2
• Time in Patent Office: Days
• US Class Current: 372/102
• CPC Class Codes: H01S 3/1055 one of the reflectors being constituted by a diffraction grating

Abstract

A tunable optoelectronic device comprising: a resonant grating filter exhibiting at least one filtering characteristic as electromagnetic radiation impinges thereupon; at least one dielectric material coupling said radiation onto said resonant grating filter and movably positioned with respect to said filter so as to adjust the at least one filtering characteristic of said filter; and, at least one driving circuit for selectively positioning said at least one dielectric material so as to tune said at least one filtering characteristic.

Claims

1. A tunable optoelectronic device suitable being suitable for freespace operation comprising:

a resonant grating filter exhibiting at least one filtering characteristic as electromagnetic radiation impinges thereupon;

at least one dielectric material coupling said radiation onto said resonant grating filter and movably positioned with respect to said filter so as to adjust the at least one filtering characteristic of said filter.

2. The device of claim 1, further comprising at least one membrane supporting said dielectric material.

3. The device of claim 1, further comprising at least one controller communicatively coupled to said filter or said membrane for selectively positioning said at least one dielectric material so as to tune said at least one filtering characteristic.

4. The device of claim 2, wherein said controller is adapted to provide a voltage suitable for adjusting an electrostatic attraction between said filter and membrane.

5. The device of claim 4, wherein further comprising a micro-electromechanical-system comprising said membrane.

6. The device of claim 2, further comprising at least one electrode for receiving a voltage for controlling an electrostatic attraction between said filter and membrane.

7. The device of claim 1, wherein said impinging electromagnetic radiation passes through said dielectric material prior to impinging upon said filter.

8. The device of claim 1, wherein said filter comprises a pattern of structures selected from the group consisting of:

holes, strips, pillars and trenches.

9. The device of claim 1, wherein said filter comprises an upper cladding layer, a core and a lower cladding layer.

10. The device of claim 9, wherein said upper and lower cladding layers comprise SiO2 and said core comprises SiN.

11. The device of claim 10, wherein said upper cladding layer has a thickness of approximately 0.1 micron, said core has a thickness of approximately 0.4 microns and said lower cladding layer has a layer of approximately 1.5 microns.

12. The device of claim 10, wherein said dielectric material comprises SiN.

13. The device of claim 12, wherein said upper cladding layer has a thickness of approximately 1 micron, said core has a thickness of approximately 0.4 microns, said lower cladding layer has a layer of approximately 1.5 microns and said dielectric material has a thickness of approximately 0.4 microns.

14. The device of claim 1, further comprising a semiconductor optical amplifier, wherein said dielectric material is optically interposed between said filter and amplifier in freespace.

15. The device of claim 14, wherein said amplifier and filter define a cavity of an external cavity laser.

16. The device of claim 14, further comprising collimating optics optically interposed between said amplifier and filter.

17. The device of claim 14, wherein said amplifier is a laser.

18. The device of claim 17, wherein said laser is a type III-V semiconductor semiconductor optical amplifier.

19. The device of claim 17, wherein said laser is a Distributed Bragg Reflector laser.

20. The device of claim 15, further comprising at least one controller operatively coupled to at least said filter or dielectric material so as to adjust an operating wavelength of said external cavity laser by adjusting a distance between said dielectric material and filter.

21. A method for tuning at least one operating characteristic of a photonic device being suitable for freespace operation, said method comprising:

applying a voltage to across a resonant grating filter and at least one dielectric material coupling electromagnetic radiation onto said resonant grating filter so as to selectively position said dielectric material with respect to said filter;

determining an operating characteristic of said photonic device; and

,

adjusting said applied voltage responsively to said determined characteristic.

22. The method of claim 21, further wherein said applied voltage selectively positions at least one membrane supporting said at least one dielectric material.

23. The method of claim 22, wherein said controller is adapted to provide a voltage suitable for adjusting an electrostatic attraction between said filter and membrane.

24. The method of claim 23, wherein said voltage activates at least one micro-electro-mechanical-system comprising said membrane.

25. The method of claim 21, further comprising passing electromagnetic radiation through said dielectric material so as to couple onto said filter to enable said determining.

26. The method of claim 21, wherein said filter comprises a pattern of structures selected from the group consisting of:

holes, strips, pillars and trenches.

27. The method of claim 26, wherein said pattern has a period on the order of approximately 0.9 microns.

28. The method of claim 28, wherein said structures have a depth of on the order of approximately 0.02 microns.

30. The method of claim 28, wherein said structures have a depth of on the order of approximately 0.05 microns.

31. The method of claim 30, wherein said pattern is chirped.

32. A method of making a optoelectric device, comprising:

forming a lower cladding, a core and an upper cladding;

patterning a plurality of nanostructures into said upper cladding;

transferring said patterned nanostructures into said upper cladding; and

,

building a membrane on said formed nanostructure.

33. The method of claim 32, further comprising

forming lower electrode pattern;

depositing sacrificial layer;

forming holes into the sacrificial layer suitable for membrane support;

depositing membrane layer;

forming window on said membrane layer;

depositing top electrode contact; and

,

removing said sacrificial layer through the window.

34. A free-spaced optical performance monitor suitable for monitoring an incoming transmission, said monitor comprising

a device;

and,

a detector,

wherein said device is suitable for being selectively wavelength tuned, thereby selectively sampling the incoming transmission incident at said detector, said detector responding to the selected wavelength, thereby creating a measured spectrum.

35. The monitor of claim 34, wherein the spectral shape of said device is known, and wherein the spectral shape is deconvolved with said measured spectrum, thereby producing a real spectrum.

36. The monitor of claim 34, wherein said device operates in reflection.

37. The monitor of claim 34, wherein said device operated in transmission.

38. A free-space module suitable for interacting with an incoming transmission utilizing a wavelength tunable device, the free-space module comprising:

a demultiplexer suitable for dividing the energy propagation into parts, each part comprising approximately an equal wavelength portion of said energy propagation; and

,

a plurality of reflectors suitable for interacting with the divided energy propagation, each reflector comprising an upper cladding and a lower cladding having a core substantially disposed there between and suitable for being optically coupled to said demultiplexer;

a pattern of nanostructures positioned substantially on said upper cladding distal to said core so as to define a reflectivity for the energy propagating through said demultiplexer; and

, a movable membrane aligned with said pattern of nanostructures so as to at least partially define a gap there between;

wherein, said gap may be selectively controlled upon actuation of said movable membrane so as to cause a corresponding change in said reflectivity, thereby determining the add/drop characteristics of operating wavelength portion.

39. The module of claim 38, further comprising a circulator optically coupled to said demultiplexer, said circulator being suitable for input and output coupling.

40. The module of claim 38, wherein said demultiplexer includes at least one of a grating, grism, and prism.

41. The module of claim 38, wherein said demultiplexer includes an echelle grating.

42. The module of claim 38, wherein said plurality of reflectors includes at least one reflector suitable for use as a tunable narrow-band reflective mirror.

43. The module of claim 38, wherein said plurality of reflectors includes at least one reflector suitable for use as a tunable notch filter.

44. The module of claim 38, wherein at least one of said plurality of reflectors substantially transmits wavelengths to be dropped from the module.

45. The module of claim 38, wherein at least one of said plurality of reflectors substantially reflects wavelengths continuing to propagate.

46. The module of claim 38, wherein at least one of said plurality of reflectors is configured to transmit a previously substantially unused wavelength, thereby injecting this wavelength into the system.

47. An optical performance monitor suitable for use in monitoring electromagnetic radiation, said monitor comprising:

a resonant grating filter exhibiting at least one filtering characteristic as electromagnetic radiation impinges thereupon;

at least one dielectric material coupling said radiation onto said resonant grating filter and movably positioned with respect to said filter so as to adjust the at least one filtering characteristic of said filter; and

,

a detector for monitoring said radiation after said radiation impinges upon said resonant grating filter,

wherein, a portion of said radiation impinging upon said resonant grating filter is selected by said filter as determined by the position of said at least one dielectric material, said portion being monitored by said detector,

wherein, said at least one filtering characteristic is known, and

wherein, said monitored signal is mathematically manipulated with said at least one filtering characteristic, thereby resulting in the real spectrum of the electromagnetic radiation.

48. A dynamic gain equalizer being suitable for balancing channels associated with an electromagnetic signal, said equalizer comprising:

at least one resonant grating filter exhibiting at least one filtering characteristic as said electromagnetic signal impinges thereupon, said filtering characteristic including at least one pass-band and at least one edge of said pass-band;

at least one dielectric material coupling said signal onto said resonant grating filter and movably positioned with respect to said filter so as to adjust the at least one filtering characteristic of said filter,

wherein, at least one of said channels is operated upon by said filter as determined by the position of said at least one dielectric material, and,

wherein, said filtering characteristic is suitably offset with respect to said at least one channel to facilitate utilizing said edge of said pass band to at least partially gain equalize said channel with respect to said channels.