Wide-angle, aliasing-free beam steering using aperiodic emitter arrays
A transmission circuit includes an array of subarrays of emitters with quasi-periodic spacing. A first subarray of emitters emits a source signal, and a second subarray of emitters emits the source signal. The first and second subarrays are separated by a subarray spacing that quasi-periodic, wherein the spacing between different subarrays is different. The quasi-periodic subarray spacing is to cause constructive interference of a main lobe of the emissions from the subarrays, and to cause non-constructive interference of sidelobes of the emissions. The spacing between emitters in the subarrays can vary from one subarray to another.
1. A transmission circuit, comprising:
a signal generation circuit to provide a source signal;
a first subarray of emitters coupled to the signal generation circuit, to emit the signal from the transmission circuit, the first subarray having at least three emitters with periodic emitter spacing, where any adjacent emitters of the first subarray have a same first emitter spacing;
a second subarray of emitters coupled to the signal generation circuit, to emit the signal from the transmission circuit, the second subarray having at least three emitters with periodic emitter spacing, where any adjacent emitters of the second subarray have a same second emitter spacing, the second emitter spacing different from the first emitter spacing; and
a third subarray of emitters coupled to the signal generation circuit, to emit the signal from the transmission circuit, the third subarray having at least three emitters with periodic emitter spacing, where any adjacent emitters of the third subarray have a same third emitter spacing, the third emitter spacing different from the first emitter spacing and the second emitter spacing;
wherein the subarrays are separated by aperiodic spacing, with a first subarray spacing between the first and second subarrays that is different from a second subarray spacing between the second and third subarrays.
2. The transmission circuit of claim 1 , wherein the transmission circuit comprises an optical transmission circuit, and the first subarray of emitters, the second subarray of emitters, and the third subarray of emitters comprise optical emitters.
3. The transmission circuit of claim 2 , wherein the first, second, and third subarrays comprise grating couplers.
4. The transmission circuit of claim 2 , further comprising a phased array of waveguides to convey an optical signal from the signal generation circuit to the optical emitters.
5. The transmission circuit of claim 4 , wherein the phased array of waveguides is to electrically cause phase offsets in the waveguides responsive to application of control signal voltages to the phased array of waveguides to beamsteer the optical signal emission from the emitters.
6. The transmission circuit of claim 1 , wherein the aperiodic spacing of the subarrays comprises spacing calculated based on a wavelength of the source signal, to cause constructive interface of a main lobe of emissions from the first, second, and third subarrays, and cause destructive interference of sidelobes of the emissions.
7. The transmission circuit of claim 6 , wherein the second subarray spacing is greater than the first subarray spacing.
8. The transmission circuit of claim 6 , wherein the second emitter spacing is greater than the first emitter spacing, and the third emitter spacing is greater than the second emitter spacing.
9. The transmission circuit of claim 1 , further comprising:
a first phase tuner between the first and second subarrays to control propagation of the source signal between the first and second subarrays.
10. The transmission circuit of claim 1 , wherein the first, second, and third subarrays couple to each other in a serial feed architecture where the first subarray couples to the source generation circuit to receive the source signal, the second subarray couples to the source generation circuit via the first subarray, and the third subarray couples to the source generation circuit via the second subarray.
11. The transmission circuit of claim 1 , wherein a largest emitter spacing of the subarrays is smaller than smallest subarray spacing between the subarrays.
12. An apparatus to transmit a wireless signal, comprising:
a photonic integrated circuit (I/C) including
a signal generation circuit to provide an optical signal;
a first subarray of emitters coupled to the signal generation circuit, to emit the optical signal from the transmission circuit, the first subarray having at least three emitters with periodic emitter spacing, where any adjacent emitters of the first subarray have a same first emitter spacing;
a second subarray of emitters coupled to the signal generation circuit, to emit the optical signal from the transmission circuit, the second subarray having at least three emitters with periodic emitter spacing, where any adjacent emitters of the second subarray have a same second emitter spacing, the second emitter spacing different from the first emitter spacing; and
a third subarray of emitters coupled to the signal generation circuit, to emit the optical signal from the transmission circuit, the third subarray having at least three emitters with periodic emitter spacing, where any adjacent emitters of the third subarray have a same third emitter spacing, the third emitter spacing different from the first emitter spacing and the second emitter spacing;
wherein the subarrays are separated by aperiodic spacing, with a first subarray spacing between the first and second subarrays that is different from a second subarray spacing between the second and third subarrays; and
a photodetector to receive a reflection signal in response to emission of the optical signal from the multiple subarrays.
13. The apparatus of claim 12 , wherein the emitters comprise grating couplers.
14. The apparatus of claim 12 , further comprising a phased array of waveguides to convey an optical signal from the signal generation circuit to the emitters.
15. The apparatus of claim 14 , wherein the phased array of waveguides is to electrically cause phase offsets in the waveguides responsive to application of control signal voltages to the phased array of waveguides to beamsteer the optical signal emission from the emitters.
16. The apparatus of claim 12 , wherein the aperiodic spacing of the subarrays comprises spacing calculated based on a wavelength of the source signal, to cause constructive interface of a main lobe of emissions from the first, second, and third subarrays, and cause destructive interference of sidelobes of the emissions.
17. The apparatus of claim 16 , wherein the second subarray spacing is greater than the first subarray spacing.
18. The apparatus of claim 16 , wherein the second emitter spacing is greater than the first emitter spacing, and the third emitter spacing is greater than the second emitter spacing.
19. The apparatus of claim 12 , wherein the first, second, and third subarrays couple to each other in a serial feed architecture where the first subarray couples to the source generation circuit to receive the source signal, the second subarray couples to the source generation circuit via the first subarray, and the third subarray couples to the source generation circuit via the second subarray.
20. The apparatus of claim 12 , wherein a largest emitter spacing of the subarrays is smaller than smallest subarray spacing between the subarrays.