Multifunctional optical device having a spatial light modulator with an array of micromirrors

• US 20040008401A1
• Filed: 01/28/2003
• Published: 01/15/2004
• Est. Priority Date: 04/03/2001
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Cidra Sarl (Nordic Cultural & Educational Foundation)
• Inventors: OʼKeefe, Christian, Kersey, Alan D., Davis, Michael A., Moon, John A., Dunphy, James R., Pinto, Joseph, Sirkis, James S., Szczepanek, Paul
• Granted Patent: US 7,126,740 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• 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 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/264 with optical elements between opposed fibre ends which perform a function other than beam splitting having lens focusing means G02B6/32; utilising prism or grating G02B6/34
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: G02B 6/3516 the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array 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 6/4215 the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers G02B6/4246 takes precedence
• 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: H04B 10/00 Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
• CPC Class Codes: H04J 14/0208 Interleaved arrangements
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04Q 2011/0009 using wavelength filters
• CPC Class Codes: H04Q 2011/0018 using tunable transmitters or receivers
• CPC Class Codes: H04Q 2011/0026 : using free space propagation (e.g. lenses, mirrors)

Abstract

A reconfigurable multifunctional optical device has an optical arrangement for receiving an optical signal, each having optical bands or channels, and a spatial light modulator for reflecting the at least one optical signal provided thereon. The optical arrangement features a free optics configuration with a light dispersion element for spreading each optical signal into one or more respective optical bands or channels for performing separate optical functions on each optical signal. The spatial light modulator includes a micro-mirror device with an array of micro-mirrors, and the respective optical bands or channels reflect off respective micro-mirrors. The free optics configuration includes a common set of optical components for performing each separate optical function on each optical signal. The separate optical functions reflect off separate non-overlapping areas on the spatial light modulator. The separate optical functions include optical switching, conditioning or monitoring functions.

Claims

1. A reconfigurable multifunctional optical device comprising an optical arrangement for receiving at least one optical signal, each optical signal having one or more optical bands or channels, and a spatial light modulator for reflecting the at least one optical signal provided thereon,

the optical arrangement having a free optics configuration with a light dispersion element for spreading each optical input signal into one or more respective optical bands or channels on the spatial light modulator for performing separate optical functions on each optical signal.

2. A reconfigurable multifunctional optical device according to claim 1, wherein the separate optical functions include reflecting the at least one optical signal off separate non-overlapping areas on the spatial light modulator.

3. A reconfigurable multifunctional optical device according to claim 1, wherein the separate optical functions include different optical functions.

4. A reconfigurable multifunctional optical device according to claim 1, wherein the separate optical functions include optical switching, conditioning or monitoring functions such as either an optical add/drop multiplexer function, an optical channel monitor function, an optical cross-connect function, an optical interleaver/deinterleaver, an optical filtering function, or any some combination thereof.

5. A reconfigurable multifunctional optical device according to claim 1, wherein the light dispersion elements include either a diffraction grating, an optical splitter, a holographic device, a prism, or a combination thereof.

6. A reconfigurable multifunctional optical device according to claim 5, wherein the diffraction grating is a blank of polished fused silica or glass with a reflective coating having a plurality of grooves either etched, ruled or suitably formed thereon.

7. A reconfigurable multifunctional optical device according to claim 1, wherein the spatial light modulator includes an array of micro-mirrors and is programmable for reconfiguring the reconfigurable multifunctional optical device to perform the first optical function or the second optical function by changing a switching algorithm that drives the array of micro-mirrors.

8. A reconfigurable multifunctional optical device according to claim 7, wherein the light dispersion element is oriented to spread the optical signal along a spectral axis, wherein the spectral axis is parallel to the tilt axis of the micromirrors of the spatial light modulator.

9. A reconfigurable multifunctional optical device according to claim 1, wherein the spatial light modulator includes an array of micro-mirrors having a multiplicity of micro-mirrors that are separately controllable for tilting on an axis depending on a control signal in accordance with a switching algorithm.

10. A reconfigurable multifunctional optical device according to claim 1, wherein the at least one optical signal includes a wavelength division multiplexed (WDM) optical input signal having a plurality of wavelengths and a corresponding plurality of optical bands or channels, each optical band or channel reflecting off a respective group of micro-mirrors of the micro-mirror device.

11. A reconfigurable multifunctional optical device according to claim 1, wherein the spatial light modulator is selectively reconfigurable by statically or dynamically modifying a switching algorithm to accommodate different channel spacing, the shape of the light beam, or the center wavelength of the light beam of the at least one optical signal.

12. A reconfigurable multifunctional optical device according to claim 8, wherein the switching algorithm is based on the wavelength of the at least one optical signal.

13. A reconfigurable multifunctional optical device according to claim 10, wherein the respective group of micro-mirrors are collectively tilted to reflect channels in the at least one optical signal.

14. A reconfigurable multifunctional optical device according to claim 1, wherein each micro-mirror is tiltable in either a first position or a second position along an axis either substantially parallel to the spectral axis of the at least one optical signal, parallel to the spatial axis of the at least one optical signal, or at an angle of 45 degrees in relation to the spatial axis.

15. A reconfigurable multifunctional optical device according to claim 1, wherein the optical arrangement includes one or more optical portions that provide the at least one optical signal to the spatial light modulator, and also provide reflected optical signals depending on the first optical function and the second optical function.

16. A reconfigurable multifunctional optical device according to claim 15, wherein the one or more optical portions include either one or more circulators, one or more waveguides, or a combination thereof.

17. A reconfigurable multifunctional optical device according to claim 16, wherein the one or more circulators includes a pair of circulators.

18. A reconfigurable multifunctional optical device according to claim 16, wherein the one or more waveguides includes a pair of capillary tubes.

19. A reconfigurable multifunctional optical device according to claim 16, wherein the one or more circulators includes a three port circulator.

20. A reconfigurable multifunctional optical device according to claim 15, wherein the one or more optical portions include a pair of optical portions, including one optical portion for providing one optical signal to the spatial light modulator, and another optical portion for providing another optical signal to the spatial light modulator.

21. A reconfigurable multifunctional optical device according to claim 15, wherein the one or more optical portions include a collimator, a reflective surface, the dispersion element, a bulk lens, or a combination thereof.

22. A reconfigurable multifunctional optical device according to claim 21, wherein the collimator includes either an aspherical lens, an achromatic lens, a doublet, a GRIN lens, a laser diode doublet, or a combination thereof.

23. A reconfigurable multifunctional optical device according to claim 21, wherein the reflective surface includes a mirror.

24. A reconfigurable multifunctional optical device according to claim 21, wherein the bulk lens includes a Fourier lens.

25. A reconfigurable multifunctional optical device according to claim 12, wherein the one or more optical portions provide one optical signal, the other optical signal, or a combination thereof as different channels having different wavelengths on the spatial light modulator.

26. A reconfigurable multifunctional optical device according to claim 25, wherein the different channels have a desired cross-sectional geometry, including elliptical, rectangular, square or polygonal.

27. A reconfigurable multifunctional optical device according to claim 25, wherein the spatial light modulator is configured so one group of channels is spaced at 100 GHz and another group of channels is spaced at 50 GHz.

28. A reconfigurable multifunctional optical device according to claim 15, wherein the one or more optical portions include one or more optical PDL mitigating devices for minimizing polarization dependence loss (PDL).

29. A reconfigurable multifunctional optical device according to claim 28, wherein one optical PDL mitigating device is arranged between a waveguide and a grating in the optical arrangement, and another optical PDL mitigating device is arranged between a grating and the spatial light modulator.

30. A reconfigurable multifunctional optical device according to claim 28, wherein the one or more optical PDL mitigating devices include a pair of optical PDL mitigating devices.

31. A reconfigurable multifunctional optical device according to claim 28, wherein the one or more optical PDL mitigating devices includes one optical PDL mitigating device having a polarization splitter for splitting each channel into a pair of polarized light beams and a rotator for rotating one of the polarized light beams of each optical channel.

32. A reconfigurable multifunctional optical device according to claim 31, wherein the one or more optical PDL mitigating devices includes another optical PDL mitigating device having a rotator for rotating one of the previously rotated and polarized light beams of each optical channel and a polarization splitter for combining the pair of polarized light beams of each channel.

33. A reconfigurable multifunctional optical device according to claim 28, wherein the one or more optical PDL mitigating devices includes a λ

/4 plate.

34. A reconfigurable multifunctional optical device according to claim 1, wherein the diffraction grating has a low PDL.

35. A reconfigurable multifunctional optical device according to claim 15, wherein the optical arrangement includes a chisel prism having multiple faces for modifying the direction of the at least one optical signal.

36. A reconfigurable multifunctional optical device according to claim 35, wherein the multiple faces include at least a front face, first and second beveled front faces, a rear face, a top face and a bottom face.

37. A reconfigurable multifunctional optical device according to claim 35, wherein optical light from first or second optical portions passes through one or more faces of the chisel prism, reflects off one or more internal surfaces of the chisel prism, reflects off the spatial light modulator, again reflects off the one or more internal surfaces of the chisel prism, and passes back to the first or second optical portions.

38. A reconfigurable multifunctional optical device according to claim 1, wherein

the reconfigurable multifunctional optical device includes an optical add/drop multiplexer configuration;

and

the dispersion element spreads at least one optical signal and an optical add signal so that each optical band or channel is reflected by one respective plurality of micro-mirrors of the spatial light modulator to selectively add or drop the one or more optical bands or channels to and/or from the at least one optical signal.

39. A reconfigurable multifunctional optical device according to claim 1, wherein

the reconfigurable multifunctional optical device includes an optical cross-connect configuration;

and

the light dispersion element spreads two or more optical signals so that each optical band or channel is reflected by one respective plurality of micro-mirrors of the spatial light modulator to selectively switch the one or more optical bands or channels between the two or more optical signals.

40. A reconfigurable multifunctional optical device according to claim 1, wherein the reconfigurable multifunctional optical device includes an optical channel monitor configuration having a light detector, the light dispersion element directing one or more reflected optical bands or channels reflected by one respective plurality of micro-mirrors of the spatial light modulator to provide an optical output signal, and the light detector detecting the one or more reflected optical bands or channels in the optical output signal.

41. A reconfigurable multifunctional optical device according to claim 1, wherein

the reconfigurable multifunctional optical device includes an interleaver/deinterleaver configuration;

and

the light dispersion element spreads two or more optical signals so that each optical band or channel is reflected by one respective plurality of micro-mirrors of the spatial light modulator to selectively either combine two respective sets of at least one-optical band or channel into one optical output signal, or de-combine one set of the at least one optical band or channel into two optical output signals each having a different set of the at least one optical band or channel.

42. A reconfigurable multifunctional optical device according to claim 1, wherein

the reconfigurable multifunctional optical device includes a chromatic dispersion compensation configuration for receiving an optical signal having one or more optical channels;

and

the spatial light modulator selectively reflects a respective spectral portion of a plurality of spectral bands or sections of the one or more channels from one respective plurality of micro-mirrors of the spatial light modulator to compensate each channel for chromatic dispersion.

43. A reconfigurable multifunctional optical device according to claim 1, wherein

the reconfigurable multifunctional optical device includes an optical blocking filter for receiving an optical signal having one or more optical bands or channels;

and

the spatial light modulator selectively deflects the one or more optical bands or channels from one respective plurality of micro-mirrors of the spatial light modulator to eliminate a selected band or channel or a specified selection of bands or channels from the optical signal provided along an optical return path.

44. A reconfigurable multifunctional optical device according to claim 1, wherein the at least one optical signal includes two or more optical input signals.

45. A reconfigurable multifunctional optical device according to claim 1, wherein the at least one optical signal includes one optical input signal, wherein one optical function is performed on the one optical input signal for providing an optical output signal, and wherein a second optical function is performed on the one optical output signal.

46. A reconfigurable multifunctional optical device according to claim 21, wherein the lens distance between the spatial light modulator and the bulk lens is greater than the focal length of the bulk lens.

47. A reconfigurable multifunctional optical device according to claim 21, wherein the lens distance between the spatial light modulator and the bulk lens is less than the focal length of the bulk lens.

48. A reconfigurable multifunctional optical device according to claim 1, wherein the free optics configuration includes a common set of optical components for performing the separate optical functions on each optical signal.

49. A reconfigurable multifunctional optical device according to claim 1, wherein the optical arrangement disperses optical channels so they are substantially separated.

50. A reconfigurable multifunctional optical device according to claim 1, wherein the optical arrangement disperses optical channels so they are substantially overlapping.

51. A reconfigurable multifunctional optical device according to claim 8, wherein the light dispersion element is oriented to spread the optical signal along a spectral axis, wherein the spectral axis is perpendicular to the tilt axis of the micromirrors of the spatial light modulator.