Quantum tomography and photon source optimization

Abstract

The photon source module includes a plurality of photon sources, where each photon source is configured to non-deterministically generate one or more non-entangled photons or entangled photons in response to receiving a trigger signal. When two or more photon sources produce photons simultaneously in response to the trigger signal, one photon of a first photon pair is directed to the photon processing system and one photon of a second photon pair is directed to a photon analyzer. During a repetition operation, the photon analyzer analyzes photons from each of the plurality of photon sources to determine a characteristic of each photon source, and can use this information to direct the highest quality photons to the photon processing system.

Claims

1. A quantum computing system, comprising: Multiple photon pair sources, each of the multiple photon pair sources comprising: A photon source configured to generate a photon pair in response to a trigger signal, the photon pair comprising a signal photon and an announcement photon; A beam splitter includes a beam splitter input port, a first beam splitter output port, and a second beam splitter output port, wherein the beam splitter input port is coupled to the photon source, and the beam splitter is configured to output the signal photon at the first beam splitter output port and the announcement photon at the second beam splitter output port. A detector, comprising a detector input port coupled to the second beam splitter output port and configured to detect the announced photons; and A photon detection switch includes a switch input port, a first switch output port, and a second switch output port, wherein the switch input port is coupled to the first beam splitter output port; and A photon multiplexer includes a plurality of photon routing switches, wherein each of the plurality of photon routing switches corresponds to one of the plurality of photon pair sources and includes: The input port is coupled to the first switch output port of the corresponding photon detection switch; The first multiplexer output port is coupled to the photon analyzer; and The second output port is coupled to the photon processing system.

2. The quantum computing system of claim 1, wherein, When each of the multiple photon pair sources releases a photon with each trigger signal, the photon multiplexer guides the signal photon to the photon processing system.

3. The quantum computing system of claim 1, wherein, When the plurality of photon pairs release two or more photons for each trigger signal, the photon multiplexer directs one of the signal photons to the photon analyzer.

4. The quantum computing system of claim 1, wherein, The photon processing system is a resource state generator.

5. The quantum computing system according to claim 1, wherein, The photon pair includes photons in an entangled state.

6. The quantum computing system according to claim 1, wherein, The photon source is a spatially multiplexed photon source.

7. The quantum computing system according to claim 1, wherein, The photon source is a multiple time-multiplexed photon source.

8. An apparatus comprising: A first photon source is configured to generate first photon pairs, each first photon pair comprising a first signal photon and a first announcement photon; A second photon source is configured to generate second photon pairs, each second photon pair comprising a second signal photon and a second announcement photon; A first beamsplitter includes a first beamsplitter input port and a first beamsplitter output port, wherein the first beamsplitter input port is coupled to the first photon source, and the first beamsplitter is configured to output the first signal photon at a first signal beamsplitter output port in the first beamsplitter output port, and to output the first announcement photon at a first announcement beamsplitter output port in the first beamsplitter output port. The second beam splitter includes a second beam splitter input port and a second beam splitter output port, wherein the second beam splitter input port is coupled to the second photon source, and the second beam splitter is configured to output the second signal photon at a second signal beam splitter output port in the second beam splitter output port, and to output the second announcement photon at a second announcement beam splitter output port in the second beam splitter output port. A first detector is configured to generate a first detection signal in response to the detection of the first announced photon; A second detector, configured to generate a second detection signal in response to the detection of the second announced photon; and A detection logic circuit is configured to, in response to receiving the first detection signal and the second detection signal, direct one of the first signal photons or the second signal photons to a photon analyzer and to a photon processing system.

9. The device according to claim 8, further comprising: A multiplexer that, in response to receiving one or more signals from the detection logic circuit, routes one of the first signal photons or the second signal photons to the photon analyzer and routes one of the first signal photons or the second signal photons to the photon processing system.

10. The device according to claim 8, wherein, The detection logic circuit guides the first signal photon and the second signal photon based on the quality level of each of the first signal photon and the second signal photon.

11. The device according to claim 8, wherein, In response to receiving the first signal photon or the second signal photon, the photon analyzer determines one or more characteristics of the received signal photon.

12. The device according to claim 11, wherein, One or more of the characteristics include color, jitter, wavelength, spectral width, or dispersion.

13. The device according to claim 8, wherein, During repeated operation of the first photon source and the second photon source, the photon analyzer determines one or more characteristics of a first signal photon generated by the first photon source and one or more characteristics of a second signal photon generated by the second photon source.

14. The device according to claim 13, wherein, The photon analyzer compares one or more characteristics of the first signal photon with one or more characteristics of the second signal photon.

15. The device according to claim 14, wherein, In response to the comparison, the photon analyzer sends an instruction that causes the photon processing system to receive more first signal photons than second signal photons.

16. The device of claim 9 further includes a cross switch that redirects signal photons routed by the multiplexer to the photon analyzer back to the photon processing system.

17. A method for generating photons, the method comprising: A first photon pair is generated using a first photon source, the first photon pair comprising a first signal photon and a first announcement photon; A second photon pair is generated using a second photon source, the second photon pair comprising a second signal photon and a second announcement photon; A first detection signal is generated in response to the detection of the first announced photon; A second detection signal is generated in response to the detection of the second announced photon; as well as In response to the first detection signal, the first photon detection switch is switched to route the first signal photon to the multiplexer; In response to the second detection signal, a second photon detection switch is switched to route the second signal photon to the multiplexer; In response to the detection logic circuit receiving the first detection signal and the second detection signal, the first signal photon is routed to the photon analyzer and the second signal photon is directed to the photon processing system.

18. The method according to claim 17, wherein, The routing is performed by the multiplexer controlled by the detection logic circuit.

19. The method according to claim 18, wherein, The detection logic circuit guides the multiplexer to route the first signal photon and the second signal photon based on the quality level of each of the first signal photon and the second signal photon.

20. The method of claim 17, wherein, In response to receiving the first signal photon or the second signal photon, the photon analyzer determines one or more characteristics of the received signal photon.

21. The method according to claim 20, wherein, One or more of the characteristics include color, jitter, wavelength, spectral width, or dispersion.

22. The method according to claim 21, wherein, During repeated operation of the first photon source and the second photon source, the photon analyzer determines one or more characteristics of the first signal photon and one or more characteristics of the second signal photon.

23. The method according to claim 22, wherein, In response to determining one or more characteristics of the first signal photon and the second signal photon, the photon analyzer sends an instruction that causes the photon processing system to receive more first signal photons than second signal photons.

24. A photon source, comprising: Multiple photon sources are configured to generate photon pairs in response to receiving a trigger signal rather than deterministically, wherein each photon pair includes a signal photon and an announcement photon, and each photon source includes a beamsplitter including a beamsplitter input port, a first beamsplitter output port, and a second beamsplitter output port, wherein the beamsplitter input port is coupled to each photon source, and the beamsplitter is configured to output the signal photon at the first beamsplitter output port and the announcement photon at the second beamsplitter output port; Multiple photon detectors, each photon detector including a detector input port coupled to the output port of the second beam splitter and configured to detect the announced photon, and coupled to a corresponding photon source among the multiple photon sources and configured to generate a corresponding detection signal when the announced photon in each generated photon pair is detected; Multiple photon detection switches, each photon detection switch including a switch input port, a first switch output port, and a second switch output port, wherein the switch input port is coupled to the first beam splitter output port; and A photonic multiplexer includes multiple photonic routing switches, each coupled to a corresponding photon source and configured to direct a corresponding signal photon to a photonic processing system or a photonic analyzer. The multiplexer includes an input port, a first multiplexer output port, and a second output port. The input port is coupled to the first switch output port of the corresponding photon detection switch, the first multiplexer output port is coupled to the photonic analyzer, and the second output port is coupled to the photonic processing system. A photon detection logic circuit is configured to receive each corresponding detection signal and, in response to receiving more than one detection signal for each trigger signal, send a control signal to the plurality of photon routing switches, the plurality of photon routing switches causing one signal photon to be routed to the photon analyzer and causing one signal photon to be routed to the photon processing system.

25. The photon source according to claim 24, wherein, In response to receiving the signal photon, the photon analyzer determines one or more characteristics of the signal photon.

26. The photon source according to claim 25, wherein, After receiving multiple trigger signals, the photon analyzer determines one or more characteristics of the signal photons generated by each of the multiple photon sources and rates the quality of each photon source.

27. The photon source according to claim 26, wherein, In response to receiving more than one detection signal for each trigger signal, the photon analyzer sends one or more signals that route signal photons from the highest quality photon source to the photon processing system.

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