Reduced crosstalk photonic switch
Described are various configurations of reduced crosstalk optical switches. Various embodiments can reduce or entirely eliminate crosstalk using a coupler that has a power-splitting ratio that compensates for amplitude imbalance caused by phase modulator attenuation. Some embodiments implement a plurality of phase modulators and couplers as part of a dilated switch network to increase overall bandwidth and further reduce potential for crosstalk.
1. A method for routing light using a dilated switch, the method comprising:
receiving light using a plurality of switches in the dilated switch, at least one of the plurality of switches including a shaped coupler having a physical shape that compensates for attenuation differences of light input into the shaped coupler;
generating modulated light by phase shifting the light using a phase modulator in the dilated switch, the modulated light exhibiting attenuation caused by the phase modulator; and
coupling the modulated light using the shaped coupler such that constructive interference occurs for a first output port of the shaped coupler and destructive interference occurs for a second output port of the shaped coupler.
2. The method of claim 1 , wherein the dilated switch comprises four switches including the at least one of the plurality of switches having the shaped coupler.
3. The method of claim 2 , wherein two or more of the four switches have shaped couplers to compensate for attenuation differences.
4. The method of claim 1 ; wherein the at least one of the plurality of switches comprises the phase modulator and an additional phase modulator.
5. The method of claim 4 , further comprising:
splitting the light into beam components; wherein the modulated light is generated by the phase modulator using one of the beam components.
6. The method of claim 5 , wherein the light is split into beam components using an additional coupler.
7. The method of claim 6 , wherein the shaped coupler and the additional coupler are Mach-Zehnder Interferometers.
8. The method of claim 5 , wherein the light includes a data stream, and the beam components include facsimiles of the data stream.
9. The method of claim 5 , wherein the additional phase modulator receives another of the beam components, and wherein the modulated light is phase shifted such that it is out of phase from the another of the beam components.
10. The method of claim 9 , wherein the additional phase modulator is in an off-state that passes the another of the beam components un-shifted.
11. The method of claim 1 , wherein the phase modulator is a silicon-based modulator that generates the modulated light by phase shifting based on a quantity of embedded positive and negative carriers in the phase modulator.
12. The method of claim 1 , wherein each of the plurality of switches of the dilated switch comprises one or more phase modulators.
13. The method of claim 1 , wherein the shaped coupler has a power splitting ratio that compensates for attenuation in the modulated light.
14. The method of claim 1 , wherein the shaped coupler has tapered sides that modify a superposition of light in the shaped coupler such that a power splitting ratio of the shaped coupler compensates for attenuation in the modulated light.
15. The method of claim 1 , wherein the dilated switch comprises two input ports and two output ports.
16. A dilated switch comprising:
a phase modulator that generates modulated light by phase shifting light, the modulated light exhibiting attenuation caused by the phase modulator; and
a plurality of switches, at least one of the plurality of switches including a shaped coupler having a physical shape that compensates for attenuation differences of light input into the shaped coupler such that constructive interference occurs for a first output port of the shaped coupler and destructive interference occurs for a second output port of the shaped coupler.
17. The dilated switch of claim 16 , wherein the dilated switch comprises four switches including the at least one of the plurality of switches having the shaped coupler, and including another switch having another shaped coupler having the physical shape.
18. The dilated switch of claim 16 , further comprising:
an optical splitter to generate a first beam component and a second beam component, the modulated light generated by the phase modulator from the first beam component.
19. The dilated switch of claim 18 , comprising:
an additional phase modulator that operates in an off state that does not phase shift the second beam component while the first beam component is phase shifted by the phase modulator.
20. A dilated switch comprising:
a first switch component comprising a 1×2 optical coupler that inputs into a set of phase modulators that input into a 2×2 shaped optical coupler, the 2×2 shaped optical coupler having a physical shape that compensates for an attenuation difference caused by one of the set of phase modulators;
a second switch component comprising an additional 1×2 optical coupler that inputs into an additional set of phase modulators that input into an additional 2×2 shaped optical coupler, the additional 2×2 shaped optical coupler having the physical shape that compensates for an attenuation difference caused by one of the additional set of phase modulators;
a third switch component comprising a further 2×2 optical coupler that inputs into a further set of phase modulators that input into a 2×1 optical coupler; and
a fourth switch component comprising a supplementary 2×2 optical coupler that inputs into a supplementary set of phase modulators that input into a supplementary 2×1 optical coupler.