Single-photon detection device and single-photon detection method

1 . A single-photon detection device, comprising a plurality of interference units, wherein each of the plurality of interference units comprises:

a signal divider configured to divide input signals into first signals and second signals, wherein the input signals comprise electrical signals generated by a single-photon sensor in response to incident photons and interference signals generated by a capacitive response of gating signals, and both the first signals and the second signals comprise the electrical signals and the interference signals;

a first signal path coupled to the signal divider and configured to receive and transmit the first signals;

a second signal path coupled to the signal divider and configured to receive the second signals and filter out and transmit signals with a preset frequency component from the second signals, wherein the second signal path comprises a narrow band filter with a passband including the preset frequency component;

an independent phase shifter arranged in the second signal path and configured to shift a phase of the transmitted signals by 180 degrees, wherein the phase shifter comprises one or more of an RF transmission line, an analog voltage-controlled phase shifter, a numerical control step phase shifter, a capacitance network phase shifter, an inductance network phase shifter and a capacitance-inductance hybrid network phase shifter; and

a coupler coupled to the first signal path and the second signal path and configured to receive and couple output signals of the first signal path and the second signal path and output the coupled signals;

wherein the plurality of interference units is cascaded, and the second signal path of each of the interference units filters out the interference signals corresponding to one of the frequency components of the gating signals.

2 . The single-photon detection device according to claim 1 , wherein a difference between transmission distances of the first signal path and the second signal path is less than a first preset value.

3 . The single-photon detection device according to claim 1 , wherein the passband bandwidth of the narrow band filter is less than or equal to 10 MHz, and the narrow band filter comprises one or more of a surface acoustic wave filter, a bulk acoustic wave filter and a dielectric filter.

4 . The single-photon detection device according to claim 1 , wherein the first signal path comprises:

a power attenuator configured to adjust a power of the first signal to make a power difference between the output signals of the first signal path and the second signal path less than a second preset value,

wherein the power attenuator comprises one or more of an analog voltage-controlled attenuator, a numerical control step attenuator and a resistance network attenuator.

5 . The single-photon detection device according to claim 1 , wherein the signal divider and the coupler each comprises a three-port RF matcher, and the three-port RF matcher comprises a first end, a second end and a third end; the three-port RF matcher of the signal divider is configured as follows:

the first end is coupled to the single-photon sensor and configured to receive the input signals;

the second end is coupled to the first signal path and configured to output the first signals; and

the third end is coupled to the second signal path and configured to output the second signals;

wherein the three-port RF matcher of the coupler is configured as follows:

the second end is coupled to the second signal path and configured to receive the output signals of the second signal path;

the third end is coupled to the first signal path and configured to receive the output signals of the first signal path; and

the first end outputs signals formed by coupling the output signals of the first signal path and the output signals of the second signal path.

6 . The single-photon detection device according to claim 5 , wherein the three-port RF matcher comprises a directional coupler, and a second end and a third end of the directional coupler have a preset signal isolation degree.

7 . The single-photon detection device according to claim 1 , further comprising:

the single-photon sensor configured to receive the incident photons and convert the incident photons into the electrical signals;

a DC voltage source coupled to the single-photon sensor and configured to provide DC bias voltage for the single-photon sensor to make the single-photon sensor in a critical breakdown state; and

a gating signal generator coupled to the single-photon sensor and configured to provide the gating signals for the single-photon sensor.

8 . The single-photon detection device according to claim 7 , wherein the gating signals comprise periodic signals, and the preset frequency component comprises one of the frequency components of the gating signals.

9 . The single-photon detection device according to claim 1 , further comprising:

a plurality of signal amplifiers, wherein each of the signal amplifiers is arranged in front of one of the interference units in a transmission direction of the input signals and configured to amplify the input signals; and

a low-pass filter arranged behind the plurality of interference units in the transmission direction of the input signals and configured to perform low-pass filtering on the output signals filtered by the plurality of interference units.

10 . An integrated circuit chip, comprising the single-photon detection device according to claim 1 integrated thereon.

11 . A method for single-photon detection using the single-photon detection device according to claim 1 , comprising:

providing, by a DC voltage source, DC bias voltage for the single-photon sensor so as to make the single-photon sensor in a critical breakdown state;

providing, by a gating signal generator, the gating signals for the single-photon sensor;

receiving the incident photons and converting the incident photons into the electrical signals, by the single-photon sensor;

dividing, by the signal divider, the input signals into the first signals and the second signals, the input signals comprising the electrical signals and the interference signals generated by the capacitive response of the gating signals;

receiving and transmitting the first signals, by the first signal path;

receiving the second signals, and filtering out and transmitting signals with the preset frequency component from the second signals, by the second signal path;

shifting, by the phase shifter, the phase of transmission signals by 180 degrees; and

receiving and coupling output signals of the first signal path and the second signal path, and outputting the coupled signals, by the coupler;

wherein the single-photon detection device comprises the plurality of interference units cascaded, the preset frequency component comprises one of the frequency components of the gating signals, and the method further comprises:

filtering out, by the second signal path of each of the interference units, the interference signals corresponding to one of the frequency components of the gating signals.

12 . The method according to claim 11 , wherein a difference between transmission distances of the first signal path and the second signal path is less than a first preset value.

13 . The method according to claim 11 , wherein the second signal path comprises the narrow band filter with a passband including the preset frequency component, and the passband bandwidth of the narrow band filter is less than or equal to 10 MHz; and the method further comprises:

filtering, by the narrow band filter, the second signals.

14 . The method according to claim 11 , wherein the first signal path comprises a power attenuator, and the method further comprises:

adjusting, by the power attenuator, a power of the first signal to make a power difference between the output signals of the first signal path and the second signal path less than a second preset value.

15 . The method according to claim 11 , wherein the signal divider and the coupler each comprises a three-port RF matcher, and the three-port RF matcher comprises a first end, a second end and a third end; the three-port matcher of the signal divider is configured as follows: the first end is coupled to the single-photon sensor, the second end is coupled to the first signal path, and the third end is coupled to the second signal path; the three-port matching device of the coupler is configured as follows: the second end is coupled to the second signal path, and the third end is coupled to the first signal path; and the method further comprises:

receiving, by the first end of the three-port RF matcher of the signal divider, the input signals;

outputting, by the second end of the three-port RF matcher of the signal divider, the first signals;

outputting, by the third end of the three-port RF matcher of the signal divider, the second signals;

receiving, by the second end of the three-port RF matcher of the coupler, the output signals of the second signal path;

receiving, by the third end of the three-port RF matcher of the coupler, the output signals of the first signal path; and

outputting, by the first end of the three-port RF matcher of the coupler, signals formed by coupling the output signals of the first signal path and the output signals of the second signal path.

16 . The method according to claim 11 , wherein the single-photon detection device further comprises a plurality of signal amplifiers and a low-pass filter, each of the signal amplifiers is arranged in front of one of the interference units in a transmission direction of the input signals, the low-pass filter is arranged behind the plurality of interference units in a transmission direction of the input signals, and the method further comprises:

amplifying, by the plurality of signal amplifiers, the input signals; and

performing, by the low-pass filter, low-pass filtering on the output signals filtered by the plurality of interference units.