1. A varactor with an actuator, wherein a first actuator surface of the actuator is embodied on a substrate, and a second actuator surface is embodied on a first movable membrane,
wherein
the varactor additionally provides a second movable membrane;
the first movable membrane is arranged above an upper side of the substrate; and
the second movable membrane is arranged below the lower side of the substrate facing away from the upper side.
2. The varactor according to claim 1,
wherein,
the first actuator surface provides an electrically conducting connection to a first terminal of a direct-voltage source;
the second actuator surface provides an electrically conducting connection to a second terminal of the direct-voltage source; and
a direct voltage adjusted in the direct-voltage source is set to form an electrostatic force on the first movable membrane and on the second movable membrane.
3. The varactor according to claim 1,
wherein the first movable membrane provides a first capacitor surface, and wherein the second movable membrane provides a second capacitor surface.
4. The varactor according to claim 1,
wherein the first movable membrane and the second movable membrane are embodied from electrically insulating material.
5. The varactor according to claim 1,
wherein the first movable membrane provides a first varactor terminal, and wherein the second movable membrane provides a second varactor terminal.
6. The varactor according to claim 1,
wherein the substrate provides a third capacitor surface, and the substrate provides a third varactor terminal.
7. The varactor according to claim 1,
wherein a capacitor surface and a second actuator surface are embodied in each case on the first movable membrane and on the second movable membrane, and wherein the respective capacitor surface is arranged at a distance from the actuator surface.
8. The varactor according to claim 1,
wherein the first movable membrane and the second membrane are mounted in a movable manner through a fixing at one end of the respective membrane.
9. The varactor according to claim 8,
wherein the distance between the second actuator surface and the fixing of the respective membrane is smaller than the distance between the respective capacitor surface and the fixing of the membrane.
10. The varactor according to claim 8,
wherein the distance between the second actuator surface and the fixing of the respective membrane is greater than the distance between the respective capacitor surface and the fixing of the membrane.
11. The varactor according to claim 1,
wherein the first movable membrane and the second movable membrane are mounted through a fixing clamped in the centre of the respective membrane.
12. The varactor according to claim 1,
wherein the first movable membrane and the second movable membrane are mounted through a fixing clamped in each case at two ends of the membrane.
13. The varactor according to claim 12,
wherein the first movable membrane and the second movable membrane each provide two second actuator surfaces,
wherein a capacitor surface is arranged in each case between the two second actuator surfaces.
14. The varactor according to claim 1,
wherein the first movable membrane and the second movable membrane provides a tapering in the region of a fixing.
15. The varactor according to claim 1,
wherein a capacitor surface and a second actuator surface are embodied in each case on the first movable membrane and on the second movable membrane, and wherein the distance between the respective capacitor surface and the substrate is smaller than the distance between the second actuator surface and the substrate.
16. The varactor according to claim 1,
wherein a capacitor surface and a second actuator surface are embodied in each case on the first movable membrane and on the second movable membrane, and wherein the distance between the respective capacitor surface and the substrate is greater than the distance between the second actuator surface and the substrate.
17. The varactor according to claim 1,
wherein a capacitor surface and a second actuator surface are embodied in each case on the first movable membrane and on the second movable membrane, and wherein the respective capacitor surface provides a size different from the second actuator surface.
18. The varactor according to claim 1,
wherein a capacitor surface is embodied in each case in a different size on the first movable membrane and on the second movable membrane.
19. A varactor system with at least two varactors according to claim 1,
wherein all varactors are connected in parallel.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A device for Orbital Angular Momentum (OAM) based optical communications comprising:
a first spatial light modulator configured to down-convert a first plurality of higher-order OAM modes from a communication signal to a second plurality of higher-order OAM modes and a first Gaussian mode;
a second spatial light modulator configured to drop the first Gaussian mode and add a second Gaussian mode to the second plurality of higher-order OAM modes, wherein the first Gaussian mode is different from the second Gaussian mode; and
a third spatial light modulator configured to up-convert the second plurality of higher-order OAM modes and the second Gaussian mode to a third plurality of higher-order OAM modes for further communications.
2. The device of claim 1, wherein the third spatial light modulator comprises two parts, an inner part configured to up-convert the at least one second Gaussian mode, and an outer part, surrounding the inner part, configured to up-convert the second plurality of OAM modes.
3. The device of claim 1, wherein the second spatial light modulator comprises an inner part, and an outer part, surrounding the inner part, the inner part reflects the at least first Gaussian mode, and the outer part reflects the modes of the second plurality of OAM modes other than the first Gaussian mode.
4. The device of claim 1, comprising a fourth spatial light modulator configured to down-convert a fourth plurality of higher-order OAM modes from a communication signal to a fifth plurality of higher-order OAM modes and a third Gaussian mode.
5. The device of claim 4, wherein the third Gaussian mode is the second Gaussian mode.
6. The device of claim 4, wherein the second spatial light modulator is configured to drop the third Gaussian mode, and add the first Gaussian mode to the fifth plurality of higher-order OAM modes.
7. The device of claim 6, comprising a fifth spatial light modulator configured to up-convert the fifth plurality of higher-order OAM modes and the first Gaussian mode to a sixth plurality of higher-order OAM modes for further communication.
8. The device of claim 7, wherein the fifth spatial light modulator comprises two parts, an inner part configured to up-convert the first Gaussian mode, and an outer part, surrounding the inner part, configured to up-convert the fifth plurality of higher-order OAM modes.
9. The device of claim 8, wherein the inner part of the fifth spatial light modulator is configured such that the angle of reflection of the first Gaussian mode is greater than the angle of incidence of the first Gaussian mode.
10. The device of claim 9, wherein the outer part of the fifth spatial light modulator is configured such that the angle of reflection of the second plurality of higher-order OAM modes is less than the angle of incidence of the second plurality of higher-order OAM modes.
11. An Orbital Angular Momentum (OAM) based optical communication system comprising:
a reconfigurable adddrop multiplexer configured and arranged to process a plurality of multiplexed OAM mode channels to selectively extract a first OAM mode channel of the plurality of multiplexed OAM mode channels and also insert a second OAM mode channel into the plurality of multiplexed OAM mode channels to replace the first OAM mode channel; and
a switch having two or more input ports and two or more output ports, wherein each of the ports has at least two multiplexed OAM modes, and the switch being configured and arranged to exchange data among the two or more input ports and the two or more output ports using a selection of two or more OAM modes.
12. The OAM system of claim 11, configured and arranged to change both an OAM mode and a polarization of a channel.
13. The OAM system of claim 12, wherein the switch is configured and arranged to change both the OAM mode and the polarization of the channel, the switch comprising:
a first spatial light modulator having different regions, a first of the different regions configured to redirect a Gaussian beam out of alignment with a first OAM beam and also convert the Gaussian beam into a second OAM beam different from the first OAM beam, and a second of the different regions configured to redirect the first OAM beam and shift an OAM charge of the first OAM beam;
a second spatial light modulator configured to generate the first OAM beam and the Gaussian beam from a first polarization optical signal;
a polarization beam splitter configured to split a received optical signal into the first polarization optical signal and a second polarization optical signal;
a half wave plate configured to modify the second polarization optical signal; and
a mirror configured to redirect the modified second polarization optical signal to the first spatial light modulator.
14. The OAM system of claim 13, configured and arranged to exchange data between any two of multiple multiplexed OAM beams.
15. The OAM system of claim 14, comprising:
a first programmable spatial light modulator configured to receive and convert the multiple multiplexed OAM beams;
a selective exchange spatial light modulator comprising different regions having different patterns that effect selective manipulation of OAM modes received from the first programmable spatial light modulator; and
a second programmable spatial light modulator configured to receive and covert the OAM modes manipulated at the selective exchange spatial light modulator.
16. The OAM system of claim 11, wherein the reconfigurable adddrop multiplexer comprises:
a first programmable spatial light modulator configured and arranged to selectively down-convert the first OAM mode channel to a Guassian mode that is spatially separated from remaining ones of the plurality of multiplexed OAM mode channels;
a grating having an inner part and an outer part that surrounds the inner part, wherein the inner part corresponds to the spatially separated Guassian mode, and the outer part corresponds to the remaining ones of the plurality of multiplexed OAM mode channels; and
a second programmable spatial light modulator configured and arranged to selectively up-convert any Guassian mode channel, which has been added to the plurality of multiplexed OAM mode channels, to the first OAM mode of the first OAM mode channel.
17. The OAM system of claim 16, wherein each of the first programmable spatial light modulator and the second programmable spatial light modulator comprises a liquid crystal on silicon-based spatial light modulator.
18. The OAM system of claim 11, wherein the switch comprises:
a down conversion stage configured to transform a selected OAM mode on each of the input ports to a Gaussian mode;
a mode-dependent beam-steering element configured to redirect the Gaussian modes from the input ports to swap their alignments with respect to remaining OAM modes from the input ports; and
an up conversion stage configured to transform the redirected Gaussian modes to selected OAM modes for provision to the output ports.
19. The OAM system of claim 18, wherein the switch comprises cascaded 2\xd72 optical switches.