System and method for photonic analog-to-digital conversion
A system for analog-to-digital conversion, preferably including one or more optical inputs, optical sources, phase remodulators, and/or photonic circuits, and optionally including detector banks and/or digital electronics. A method for analog-to-digital conversion, preferably including receiving an optical input signal, generating a phase-modulated optical signal, and/or generating a plurality of optical outputs, and optionally including generating a plurality of electrical outputs and/or encoding a digital representation of the outputs.
1. A method for analog-to-digital conversion, the method comprising:
receiving an analog input signal and a first optical carrier;
based on the analog input signal, modulating a phase of the first optical carrier to generate a phase-modulated optical signal;
at a photonic circuit, receiving the phase-modulated optical signal and a second optical carrier;
at the photonic circuit, generating a spatially-separated plurality of optical outputs based on the phase-modulated optical signal, comprising, at a coupler of the photonic circuit, interfering the phase-modulated optical signal with the second optical carrier;
at a detector bank comprising a plurality of detectors, receiving the spatially-separated plurality of optical outputs, wherein each optical output of the spatially-separated plurality of optical outputs is received by a different detector of the plurality of detectors; and
at the detector bank, generating a set of binary outputs, comprising, for each optical output of the spatially-separated plurality of optical outputs: generating, based on the optical output, a respective binary output of the set;
wherein the set of binary outputs is indicative of a value associated with the analog input signal.
2. The method of claim 1 , wherein the first optical carrier is substantially identical to the second optical carrier.
3. The method of claim 1 , further comprising:
receiving an optical carrier input; and
splitting the optical carrier input into the first and second optical carriers.
4. The method of claim 1 , wherein the analog input signal is an optical signal.
5. The method of claim 4 , wherein modulating the phase of the first optical carrier to generate the phase-modulated optical signal comprises, at a non-linear optical element:
receiving the analog input signal and the first optical carrier; and
modulating the phase of the first optical carrier via a non-linear optical effect.
6. The method of claim 5 , wherein the first optical carrier is the analog input signal.
7. The method of claim 6 , wherein the non-linear optical effect results in self-phase modulation of the first optical carrier within the non-linear optical element.
8. The method of claim 5 , wherein:
the first optical source comprises light within a first wavelength band;
the analog input signal comprises light within a second wavelength band, wherein the first and second wavelength bands are non-overlapping; and
the non-linear optical effect results in cross-phase modulation of the first optical carrier within the non-linear optical element.
9. The method of claim 8 , further comprising, after modulating the phase of the first optical carrier, separating the light within the second wavelength band from the phase-modulated optical signal via spectral filtering.
10. The method of claim 1 , wherein:
the analog input signal is an electrical signal;
the analog input signal is received at a phase modulator; and
the phase modulator modulates the phase of the first optical carrier to generate the phase-modulated optical signal.
11. The method of claim 10 , wherein the phase modulator is a microresonator.
12. The method of claim 10 , wherein:
the first optical carrier comprises light within a plurality of wavelength channels;
the phase modulator is a wavelength-selective modulator associated with a modulation band, wherein the modulation band is tunable, in response to the analog input signal, over a modulation window that spans the plurality of wavelength channels; and
modulating the phase of the first optical carrier to generate the phase-modulated optical signal comprises modulating the phase of light of a first wavelength channel of the plurality.
13. The method of claim 12 , wherein:
the plurality of wavelength channels consists of k wavelength channels;
the spatially-separated plurality of optical outputs consists of m single-channel outputs; and
generating the spatially-separated plurality of optical outputs further comprises:
receiving, from the coupler, a spatially-separated plurality of multi-channel signals consisting of n multi-channel signals, wherein n=m/k; and
for each multi-channel signal of the plurality, at a respective spectral filter bank, splitting the multi-channel signal into k single-channel outputs.
14. The method of claim 10 , further comprising:
receiving an optical analog signal; and
generating the analog input signal based on the optical analog signal.
15. The method of claim 1 , wherein the first and second optical carriers are substantially static.
16. The method of claim 1 , wherein the coupler comprises a multi-mode interference coupler.
17. The method of claim 1 , wherein the set of binary outputs defines a one-hot representation of the value.
18. The method of claim 17 , further comprising, based on the set of binary outputs, generating a serialized digital representation of the value.
19. The method of claim 1 , wherein each binary output of the set is an electrical output.
20. The method of claim 1 , wherein the value is indicative of an intensity of the analog input signal.