Optical interleaver/deinterleaver device having an array of micro-mirrors
View Patent ↗A reconfigurable optical interleaver/deinterleaver device combines/separates a pair of optical input signals from and/or to an optical WDM input signal. The interleaver device includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors that 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 pair of collimators, diffraction gratings and Fourier lens collectively collimate, separate and focus the optical input channels and optical add channels onto the array of micro-mirrors. Each optical channel is focused on a plurality of micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels.
1. An optical interleaver/de-interleaver device including an optical arrangement for receiving two or more optical signals, each optical signal having a respective set of at least one optical band or channel, and including a spatial light modulator having a micro-mirror device with an array of micro-mirrors for reflecting the one or more optical signals provided thereon, characterized in that
the optical arrangement comprises a free optic configuration having one or more light dispersion elements for separating the two or more optical signals so that each optical band or channel is reflected by a respective plurality of micro-mirrors to selectively either combine two respective sets of the 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.
2. An optical interleaver/de-interleaver device according the claim 1 , wherein the one or more light dispersion elements include either a diffraction grating, an optical splitter, a holographic device, a prism, or a combination thereof.
3. An optical interleaver/de-interleaver device according the claim 2 , 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.
4. An optical interleaver/de-interleaver device according the claim 2 , wherein the diffraction grating is tilted and rotated approximately 90° in relation to the spatial axis of the dispersed optical signal.
5. An optical interleaver/de-interleaver according to claim 2 , wherein the diffraction grating has a low PDL.
6. An optical interleaver/de-interleaver according the claim 1 , wherein the spatial light modulator is programmable for reconfiguring the optical interleaver/de-interleaver by changing a switching algorithm that drives the array of micro-mirrors.
7. An optical interleaver/de-interleaver according the claim 6 , wherein the spatial light modulator is 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 reflected optical signals.
8. An optical interleaver/de-interleaver according the claim 6 , wherein the switching algorithm is based on the wavelength of the optical signal and the one or more optical bands or channels being switched.
9. An optical interleaver/de-interleaver according the 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.
10. An optical interleaver/de-interleaver according the claim 1 , wherein the two or more optical signals include a wavelength division multiplexed (WDM) optical signal having a plurality of wavelengths and a corresponding plurality of optical bands or channels, each optical channel reflecting off a respective group of micro-mirrors of the micro-mirror device.
11. An optical interleaver/de-interleaver according the claim 1 , wherein the respective group of micro-mirrors are collectively tilted to reflect channels in the two or more optical signals.
12. An optical interleaver/de-interleaver according the claim 1 , wherein each micro-mirror is tiltable in either a first position or a second position along an axis either parallel to the spectral axis of the micro-mirror device, parallel to the spatial axis of the micro-mirror device, or at an angle of 45° in relation to the spatial axis.
13. An optical interleaver/de-interleaver according the claim 1 , wherein the optical arrangement includes one or more optical portions that provide the two or more optical signals to the spatial light modulator.
14. An optical interleaver/de-interleaver according the claim 13 , wherein the one or more optical portions include either one or more waveguides, one or more capillary tubes, or a combination thereof.
15. An optical interleaver/de-interleaver according the claim 14 , wherein the one or more optical portions provide the two or more optical signals to the spatial light modulator.
16. An optical interleaver/de-interleaver according the claim 14 , wherein the one or more waveguides includes a pair of circulators.
17. An optical interleaver/de-interleaver according the claim 14 wherein the one or more capillary tubes includes a pair of capillary tubes.
18. An optical interleaver/de-interleaver according the claim 14 , wherein the one or more circulators includes a three port circulator.
19. An optical interleaver/de-interleaver according the claim 13 , 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.
20. An optical interleaver/de-interleaver according the claim 13 , wherein the one or more optical portions include a collimator, a reflective surface, a dispersion device, a bulk lens, or a combination thereof.
21. An optical interleaver/de-interleaver according the claim 20 , wherein the collimator includes either an aspherical lens, an achromatic lens, a doublet, a GRIN lens, a laser diode doublet, or a combination thereof.
22. An optical interleaver/de-interleaver according the claim 20 , wherein the reflective surface includes a mirror.
23. An optical interleaver/de-interleaver according the claim 20 , wherein the reflective surface is curved.
24. An optical interleaver/de-interleaver according the claim 20 , wherein the bulk lens includes a Fourier lens.
25. An optical interleaver/de-interleaver according the claim 13 , wherein the one or more optical portions provide the two or more optical as different channels having different wavelengths on the spatial light modulator.
26. An optical interleaver/de-interleaver according the claim 25 , wherein the different channels have a desired cross-sectional geometry, including elliptical, rectangular, square or polygonal.
27. An optical interleaver/de-interleaver according the 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. An optical interleaver/de-interleaver according the claim 13 , wherein the one or more optical portions further comprise a further optical portion for receiving the two or more optical signals from the spatial light modulator and providing these same optical signals back to the spatial light modulator.
29. An optical interleaver/de-interleaver according the claim 28 , wherein the further optical portion includes a pair of reflective surfaces and lens, one reflective surface arranged at one focal length in relation to one lens and the spatial light modulator, and another reflective surface arranged at a different focal length in relation to another lens and the spatial light modulator.
30. An optical interleaver/de-interleaver according the claim 29 , wherein the one focal length is twice the length of the other focal length.
31. An optical interleaver/de-interleaver according the claim 29 , wherein the further optical portion includes a single reflective surface and lens arrangement.
32. An optical interleaver/de-interleaver according the claim 31 , wherein the lens is arranged between a reflective surface and the spatial light modulator.
33. An optical interleaver/de-interleaver according to claim 13 , wherein the one or more optical portions include one or more optical PDL mitigating devices for minimizing polarization dependence loss (PDL).
34. An optical interleaver/de-interleaver according to claim 33 , 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.
35. An optical interleaver/de-interleaver according to claim 33 , wherein the one or more optical PDL mitigating devices include a pair of optical PDL mitigating devices.
36. An optical interleaver/de-interleaver according to claim 33 , 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.
37. An optical interleaver/de-interleaver according to claim 36 , 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.
38. An optical interleaver/de-interleaver according to claim 33 , wherein the one or more optical PDL mitigating devices includes a λ/4 plate.
39. An optical interleaver/de-interleaver according to claim 13 , wherein the optical arrangement includes a chisel prism having multiple faces for modifying the direction of the one or more optical signals.
40. An optical interleaver/de-interleaver according to claim 13 , 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.
41. An optical interleaver/de-interleaver according to claim 39 , 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.
42. An optical interleaver/de-interleaver multiplexer according to claim 13 , wherein the one or more optical portions includes three optical portions, including a first optical portion for providing a first optical signal having one or more first channels to be interleaved to the spatial light modulator, a second optical portion for providing a second optical signal having one or more second channels to be interleaved to the spatial light modulator, and a third optical portion for providing the optical output signal having interleaved channels from the spatial light modulator.
43. An optical interleaver/de-interleaver according to claim 1 , wherein the free optic configuration includes a lens and a grating arranged such that the lens is placed at a distance “d” from the grating that is shorter than focal length “f” of the lens.
44. An optical add/drop multiplexer according to claim 1 , wherein the free optic configuration includes a lens and a grating arranged such that the lens is placed a distance “d” from the grating that is longer than focal length “f” of the lens.