Chromatic dispersion compensation device having an array of micromirrors
View Patent ↗A chromatic dispersion compensation device selectively delays a respective portion of spectral sections of each respective optical channel of an optical WDM input signal to compensate each optical channel for dispersion compensation, and includes a spatial light modulator having a micromirror device with a two-dimensional array of micromirrors. The micromirrors tilt or flip between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A collimator, diffraction gratings, and Fourier lens collectively collimate, disperse and focus the optical input channels onto the array of micromirrors. Each optical channel is focused onto micromirrors of the micromirror device, which effectively pixelates the optical channels. To compensate an optical channel for chromatic dispersion, a portion of the spectral sections of each channel is delayed a desired time period by tilting an array of mirrors (i.e., spectral array) disposed in each spectral section at different spatial positions on the micromirror device.
1. A chromatic dispersion compensation device for receiving an optical signal having one or more optical channels, characterized in that
the chromatic dispersion compensation device comprises a spatial light modulator having a micro-mirror device with an array of micro-mirrors for selectively reflecting a respective spectral portion of a plurality of spectral bands or sections of the one or more channels to compensate each channel for chromatic dispersion.
2. A chromatic dispersion compensation device according to claim 1 , wherein the array of micro-mirrors selectively delays by a desired time period the respective spectral portion of the plurality of spectral bands or sections of each respective optical channel of the optical signal.
3. A chromatic dispersion compensation device according to claim 2 , wherein the chromatic dispersion compensation device comprises an optical arrangement for providing the optical signal along an optical path to the array of micromirrors.
4. A chromatic dispersion compensation device according to claim 3 , wherein the optical arrangement is a free optics arrangement and the desired time period is delayed by increasing or decreasing the optical path that each spectral portion of the plurality of spectral bands or sections of each respective optical channel propagates in free space.
5. A chromatic dispersion compensation device according to claim 1 , wherein the spatial light modulator is programmable for reconfiguring the chromatic dispersion compensation device to compensate each channel for chromatic dispersion by changing a switching algorithm that drives the array of micro-mirrors.
6. A chromatic dispersion compensation device according to claim 1 , wherein the array of micro-mirrors includes 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.
7. A chromatic dispersion compensation device according to claim 1 , wherein the optical signal is a wavelength division multiplexed (WDM) optical signal having a plurality of wavelengths and a corresponding plurality of optical channels, each optical channel reflecting off a respective group of micro-mirrors of the micro-mirror device.
8. A chromatic dispersion compensation device according to claim 5 , wherein the spatial light modulator is selectively reconfigurable by statically or dynamically modifying the switching algorithm to accommodate different channel spacing, the shape of the light beam, or the center wavelength of the light beam of the optical signal.
9. A chromatic dispersion compensation device according to claim 5 , wherein the switching algorithm is based on the wavelength of the optical signal and the one or more optical channels being compensated for chromatic dispersion.
10. A chromatic dispersion compensation 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 optical input signal, parallel to the spatial axis of the optical input signal, or at an angle of 45 degrees in relation to the spatial axis.
11. A chromatic dispersion compensation device according to claim 3 , wherein the optical arrangement includes a free optics arrangement that provides the optical signal to the spatial light modulator, and also provide a compensated optical signal having each channel compensated for chromatic dispersion from the spatial light modulator.
12. A chromatic dispersion compensation device according to claim 11 , wherein the free optics arrangement includes either one or more circulators, one or more waveguides, or a combination thereof.
13. A chromatic dispersion compensation device according to claim 12 , wherein the one or more circulators includes a pair of circulators.
14. A chromatic dispersion compensation device according to claim 12 , wherein the one or more waveguides includes a pair of capillary tubes.
15. A chromatic dispersion compensation device according to claim 13 , wherein the one or more circulators includes a three port circulator.
16. A chromatic dispersion compensation device according to claim 11 , wherein the free optics arrangement includes a respective optical portion for each channel.
17. A chromatic dispersion compensation device according to claim 11 , wherein the free optics arrangement includes a collimator, a reflective surface, a dispersion element, a bulk lens, or a combination thereof.
18. A chromatic dispersion compensation device according to claim 17 , wherein the collimator includes either an aspherical lens, an achromatic lens, a doublet, a GRIN lens, a laser diode doublet, or a combination thereof.
19. A chromatic dispersion compensation device according to claim 17 , wherein the reflective surface includes a mirror.
20. A chromatic dispersion compensation device according to claim 19 , wherein the reflective surface is curved.
21. A chromatic dispersion compensation device according to claim 17 , wherein the bulk lens includes a Fourier lens.
22. A chromatic dispersion compensation device according to claim 1 , wherein the one or more optical channels have a desired cross-sectional geometry, including an elliptical, a rectangular, a square or a polygonal shape.
23. A chromatic dispersion compensation device according to claim 5 , wherein the spatial light modulator is configured so one group of optical channels is spaced at 100 GHz and another group of optical channels is spaced at 50 GHz.
24. A chromatic dispersion compensation device according to claim 11 , wherein the free optics arrangement further comprise a further optical portion for receiving a reflected optical signal from the spatial light modulator and providing a re-reflected or dispersed optical signal back to the spatial light modulator.
25. A chromatic dispersion compensation device according to claim 24 , wherein the further optical portion includes a light dispersion element for dispersing the reflected optical signal and providing a dispersed optical signal back to the spatial light modulator.
26. A chromatic dispersion compensation device according to claim 24 , wherein the further optical portion includes a reflective surface for re-reflecting the reflected optical signal back to the spatial light modulator for delaying each respective spectral portion or section to compensate each channel for chromatic dispersion.
27. A chromatic dispersion compensation device according to claim 11 , wherein the free optics arrangement includes one or more optical PDL mitigating devices for minimizing polarization dependence loss (PDL).
28. A chromatic dispersion compensation device according to claim 27 , 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.
29. A chromatic dispersion compensation device according to claim 27 , wherein the one or more optical PDL mitigating devices include a pair of optical PDL mitigating devices.
30. A chromatic dispersion compensation device according to claim 27 , 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.
31. A chromatic dispersion compensation device according to claim 30 , 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.
32. A chromatic dispersion compensation device according to claim 27 , wherein the one or more optical PDL mitigating devices includes a λ/4 plate.
33. A chromatic dispersion compensation device according to claim 17 , wherein the dispersion element has a low PDL.
34. A chromatic dispersion compensation device according to claim 11 , wherein the optical arrangement includes a chisel prism having multiple faces for modifying the direction of the optical signal.
35. A chromatic dispersion compensation device according to claim 34 , wherein the multiple faces include at least a front face, a rear face, a top face and a bottom face.
36. A chromatic dispersion compensation device according to claim 34 , wherein the optical light from the free optics arrangement 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 free optics arrangement.
37. A chromatic dispersion compensation device according to claim 1 , wherein the optical signal includes a plurality of channels, each having at least one respective spectral band or section.
38. A chromatic dispersion compensation device according to claim 1 , wherein the optical signal includes at least one channel having respective spectral bands or sections arranged in non-uniform spectral arrays on the array of micro-mirror.
39. A chromatic dispersion compensation device according to claim 38 , wherein the non-uniform spectral arrays include arrays having a different length, width, number or combination thereof on the array of micro-mirrors.
40. A chromatic dispersion compensation device according to claim 1 , wherein the optical signal includes a plurality of channels that are non-linearly disposed on the array of micro-mirrors.
41. A chromatic dispersion compensation device according to claim 17 , wherein the dispersion element includes a diffraction grating, a tilted grating, an echelle grating, an etalon, a prism or a holographic optical device.
42. A chromatic dispersion compensation device according to claim 11 , wherein the optical arrangement includes a field correction lens for respectively compensating for the one or more channels reflecting of the spatial light modulator.
43. A chromatic dispersion compensation device according to claim 24 , wherein the further optical portion includes a mirror for re-reflecting the optical signal back to the spatial light modulator.
44. A chromatic dispersion compensation device according to claim 24 , wherein the further optical portion includes a second light dispersion element for re-dipersing the optical signal back to the spatial light modulator.