1. A high-speed sine-gated single photon detector, comprising:

the detection circuit is used for detecting a single photon signal in incident light according to the first gate control pulse signal;

a reference circuit for generating a differential reference signal according to the second gating pulse signal;

the reference circuit is further used for eliminating a noise signal and a carrier wave generated by the detection circuit according to the differential reference signal, so that the high-speed sine-gated single photon detector can extract an avalanche signal from the noise signal;

the detection circuit is in parallel relationship with the reference circuit.

2. The high-speed sine-gated single photon detector of claim 1, wherein:

the detection circuit includes an avalanche diode D1 and a resistor R1.

3. The high-speed sine-gated single photon detector of claim 1, wherein:

the reference circuit includes an adjustable attenuator, a phase shifter, an avalanche diode D2, and a resistor R2.

4. The high-speed sine-gated single photon detector of claim 1, wherein:

the parasitic parameters of the detection circuit are consistent with the parasitic parameters of the reference circuit.

5. The high-speed sine-gated single photon detector according to any of claims 1-4, further comprising:

the device comprises a gate control pulse signal generator, a coupler, a power divider, a capacitor, a low noise amplifier and a comparator.

6. The high-speed sine-gated single photon detector of claim 1, wherein:

the first gating pulse signal and the second gating pulse signal are both sine gating pulse signals.

7. The high-speed sine-gated single photon detector of claim 3, wherein:

the phase shifter is configured to adjust a phase of the second gating pulse signal such that a phase difference between the first gating pulse signal and the second gating pulse signal is 180 °.

8. The high-speed sine-gated single photon detector of claim 3, wherein:

the adjustable attenuator is used for adjusting the amplitude of the second gating pulse signal so that the amplitude of the first gating pulse signal is the same as that of the first gating pulse signal.

Background

In a quantum communication system, a single photon detector is an important module, and the performance of the single photon detector directly affects the core performance of the quantum communication system, such as error rate, code rate and the like. The detection mode of the single photon detector can be divided into a gating mode and a free running mode, but at present, the single photon detector in the free running mode is immature in development, long in quenching time and recovery time and limited in maximum counting rate, so that the single photon detector in the free running mode is generally applied to the field of laser radar and the like, wherein the photon arrival time of the laser radar is uncontrollable.

The single photon detector based on the avalanche diode has small volume and low power consumption, and is the most practical single photon detector at present. The single photon detector usually works in a geiger door mode, and can greatly improve the detection performance. Photon-triggered avalanche pulse electrical signals are very weak, an avalanche diode has a capacitive effect, and gate pulses loaded on the avalanche diode can generate spike pulses through charging and discharging, so that a key technology for improving single photon detection performance is how to effectively extract weak avalanche pulse electrical signals from spike noises.

The single photon detector in the gate control mode can effectively improve the maximum counting rate and has better performance. Therefore, most of single-photon detectors used in the current mainstream quantum communication field are in a gating mode. The single-photon detectors with the gate control mode are generally divided into single-photon detectors with a square wave gate control mode and single-photon detectors with a sine gate control mode.

The process of extracting the avalanche pulse electric signal by the single photon detector in the sine gating mode comprises the following steps: and loading the sine gating pulse signal to an avalanche diode, simultaneously outputting the sine gating pulse signal and the avalanche pulse electric signal, and filtering the carrier wave in a filtering mode to obtain the avalanche pulse electric signal. Because the avalanche pulse electrical signal obtained by adopting the filtering mode is distorted, the time jitter of the avalanche pulse electrical signal is large, the integrity of the signal is difficult to ensure, the difficulty of noise suppression is relatively large, and the signal-to-noise ratio is not high.

A single photon detector with a part of square wave gating modes adopts a differential mode to extract an avalanche pulse electric signal, and the mode has the following defects: without two identical capacitive devices, the frequency spectrum of the gating pulse signal is complex, the generated noise spike signals are greatly different, and the bottom noise is difficult to remove. The time interval of two square wave gating pulse signals required to be controlled in a self-differential mode is accurate to one pulse period, and due to the fact that the time interval is long, generally, one arm of a single photon detector in a square wave gating mode uses a long cable, the difficulty in controlling the length is high, attenuation cannot be accurately controlled, the integrity of signals is difficult to guarantee, and the signal-to-noise ratio of the extracted avalanche pulse electrical signals is not high.

Disclosure of Invention

The embodiment of the invention provides a high-speed sine-gated single photon detector, which is used for solving the defects of difficulty in ensuring signal integrity and low signal-to-noise ratio in the prior art.

In order to achieve the above object, a technical solution related to a high-speed sine-gated single photon detector provided in an embodiment of the present invention includes:

and the detection circuit is used for detecting the single photon signal in the incident light according to the first gate control pulse signal.

And the reference circuit is used for generating a differential reference signal according to the second gating pulse signal.

The reference circuit is further used for eliminating a noise signal and a carrier wave generated by the detection circuit according to the differential reference signal, so that the high-speed sine-gated single photon detector provided by the embodiment of the invention can extract an avalanche pulse electrical signal from the noise signal.

The detection circuit is in parallel relationship with the reference circuit.

As a preferred embodiment of the present invention, the detection circuit includes an avalanche diode D1 and a resistor R1.

As a preferred embodiment of the present invention, the reference circuit comprises an adjustable attenuator, a phase shifter, an avalanche diode D2 and a resistor R2.

In a preferred embodiment of the present invention, the parasitic parameters of the detection circuit are identical to the parasitic parameters of the reference circuit.

The high-speed sine-gated single photon detector also comprises a gated pulse signal generator, a coupler, a power divider, a capacitor, a low-noise amplifier and a comparator.

In a preferred embodiment of the present invention, the first gating pulse signal and the second gating pulse signal are both sinusoidal gating pulse signals.

In a preferred embodiment of the present invention, the phase shifter is configured to adjust the phase of the second gating pulse signal such that the phase difference between the first gating pulse signal and the second gating pulse signal is 180 °.

As a preferred embodiment of the present invention, the adjustable attenuator is configured to adjust the amplitude of the second gating pulse signal so that the amplitude of the first gating pulse signal is the same as the amplitude of the first gating pulse signal.

The high-speed sine-gated single photon detector provided by the embodiment of the invention has the following beneficial effects:

(1) a sinusoidal gating differential mode is used for eliminating sinusoidal signal carriers, so that the problem that the integrity of signals is difficult to ensure due to filtering is avoided, and the signal-to-noise ratio can be improved;

(2) compared with a square wave gating differential mode, the sine gating differential mode is easy to realize high speed, single spectrum in differential and easy to control.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of an internal circuit of a conventional single photon detector adopting a double avalanche diode balance method.

Fig. 2 is a schematic diagram of an internal circuit of the high-speed sine-gated single photon detector according to the embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

As shown in FIG. 1, the single photon detector adopts a double avalanche photodiode balance method, and two avalanche photodiodes with consistent capacitance characteristics are selected, wherein one avalanche diode APD1 is used for detecting photons, and the other avalanche diode APD2 is used for simulating generation of spike noise signals. The gate pulse signals with opposite phases generate spike noise signals with opposite phases and consistent shapes on the avalanche photodiode APD1 and the avalanche diode APD2, and finally, the two paths of spike noise signals are added at the output end, so that the spike noise can be removed, and the avalanche pulse electrical signals can be extracted. The scheme has the following defects: the frequency spectrum of the square wave gating pulse signal is complex and is not easy to control, the generated noise spike signals are greatly distinguished, and bottom noise is difficult to remove, so that the signal-to-noise ratio of the extracted avalanche pulse electrical signal is not high.

As shown in fig. 2, the high-speed sine-gated single photon detector provided in the embodiment of the present invention includes a detection circuit, a reference circuit, a gated pulse signal generator, a coupler, a power divider, a capacitor, a low noise amplifier, and a comparator, where:

the detection circuit is used for detecting a single photon signal in incident light according to the first gate control pulse signal.

As an alternative embodiment of the invention, the first gating pulse signal is a sinusoidal gating pulse signal.

Specifically, the first gate pulse signal enters the detection circuit through a terminal a.

The reference circuit is used for generating a differential reference signal according to the second gating pulse signal.

As an alternative embodiment of the invention, the second gating pulse signal is a sinusoidal gating pulse signal.

Specifically, the second gate control pulse signal is input to the reference circuit through a terminal B.

The reference circuit is also used for eliminating a noise signal and a carrier wave in the detection circuit according to the differential reference signal, so that the high-speed sine-gated single photon detector can extract an avalanche pulse electric signal from the noise signal.

Specifically, the differential reference signal is differentiated from the noise signal in the detection circuit at the terminal C to eliminate the noise signal and the carrier in the detection circuit.

The detection circuit is in parallel relationship with the reference circuit.

As an alternative embodiment of the invention, the detection circuit comprises an avalanche diode D1 and a resistor R1.

Specifically, the avalanche diode D1 operates in the 200 MHz gated geiger mode. Photons are incident on the avalanche diode D1 to form an avalanche current, which passes through the resistor R1 to generate an avalanche pulse electrical signal.

As an alternative embodiment of the present invention, the reference circuit includes an adjustable attenuator, a phase shifter, an avalanche diode D2, and a resistor R2.

As an alternative embodiment of the invention, the parasitic parameters of the detection circuit coincide with those of the reference circuit.

The parasitic parameters of the circuit are very many, the generation reasons are mainly resistors, inductors, capacitors and the like in components and circuit boards, capacitors can be formed among parallel conductors, and the inductors and the capacitors in the components and the components can generate coupling effect due to the inductors which are arranged in order.

As an optional embodiment of the present invention, a phase difference between the first gating pulse signal and the second gating pulse signal is 180 ° and amplitudes of the first gating pulse signal and the second gating pulse signal are the same, so that the differential reference signal and the noise signal in the detection circuit can be cancelled in the differential mode network, that is, the avalanche pulse electrical signal hidden in the noise signal can be extracted.

The gated pulse signal generator is used for preparing a sinusoidal gated pulse signal.

The coupler is used for dividing the sinusoidal gating pulse signal into two parts according to different power proportions, sending the part of the sinusoidal gating pulse signal with small proportion to the monitoring module, and sending the part of the sinusoidal gating pulse signal with large proportion to the power divider.

The power divider is used for dividing the received sinusoidal gating pulse signal into two parts according to the same power proportion, sending one part of the sinusoidal gating pulse signal (a first gating pulse signal) to the detection circuit, and sending the other part of the sinusoidal gating pulse signal (a second gating pulse signal) to the adjustable attenuator.

The adjustable attenuator is used for adjusting the amplitude of the second gating pulse signal, so that the amplitude of the first gating pulse signal is the same as that of the second gating pulse signal.

The phase shifter is used for adjusting the phase of the second gating pulse signal so that the phase difference between the first gating pulse signal and the second gating pulse signal is 180 degrees.

In particular, since the first gating pulse signal and the second gating pulse signal have the same amplitude and opposite phases, the noise signal (differential reference signal) generated in the detection circuit and the noise signal generated in the detection circuit have the same amplitude and opposite phases.

The capacitor is used for filtering the extracted direct current bias voltage signal of the avalanche pulse electric signal.

The low noise amplifier is used for amplifying the avalanche pulse electric signal.

The comparator is used for converting the amplified avalanche pulse electrical signal into a digital pulse signal.

The high-speed sine-gated single photon detector provided by the embodiment of the invention comprises a detection circuit and a reference circuit, wherein the detection circuit is used for detecting a single photon signal in incident light according to a first gating pulse signal, and the reference circuit is used for generating a differential reference signal according to a second gating pulse signal. The reference circuit is also used for eliminating noise signals and carriers generated by the detection circuit according to the differential reference signals, so that the high-speed sine gated single photon detector can extract avalanche pulse electrical signals from the noise signals generated by the detection circuit, and the detection circuit and the reference circuit are in parallel connection, thereby effectively ensuring the integrity of signals and improving the signal-to-noise ratio.

It will be appreciated that the relevant features of the method and apparatus described above are referred to one another. In addition, "first", "second", and the like in the above embodiments are for distinguishing the embodiments, and do not represent merits of the embodiments.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

It should be noted that the above-mentioned embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the protection scope of the present invention.