Free operation single photon detection device adopting traveling wave quenching
By combining traveling wave quenching logic, the problems of large signal delay, high after-pulse count, and low count rate in single-photon detection devices are solved, realizing the compression of avalanche pulses and high count rate, thus expanding the application scenarios of single-photon detection technology.
Patent Information
- Application Number
- CN202511987131.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-03-13
AI Technical Summary
Existing single-photon detection devices suffer from large signal delays, high after-pulse counts, and low count rates during the quenching process, making it difficult to meet the stringent requirements of scenarios such as high-frequency spectral analysis and quantum communication.
A free-running single-photon detector employing traveling wave quenching utilizes a combination of an initial quenching isolation component, at least one stage of amplification quenching component, and a quenching signal processing component to transmit and process avalanche signals along the direction of traveling wave propagation, achieving extremely short quenching delay and high count rate.
It achieves avalanche pulse width compression to the hundreds of ps level, reduces afterpulse probability, improves counting rate, meets high-frequency detection requirements, and supports flexible configuration of various transistor types.
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Figure CN121655689A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of single-photon detection technology, and more specifically, to a free-running single-photon detection device employing traveling wave quenching. Background Technology
[0002] Single-photon detection technology is the core technology for capturing extremely weak light signals, and its core device is a single-photon avalanche diode (APD) operating in Geiger mode. In Geiger mode, the APD requires a reverse bias voltage higher than its breakdown voltage. When a single photon is incident, it excites the semiconductor material to generate an initial electron-hole pair. This charge carrier is accelerated in a strong reverse electric field and strikes the crystal lattice, triggering the "avalanche multiplication effect" and generating a detectable avalanche signal. After the avalanche signal is generated, the avalanche state of the APD must be quickly shut down by a quenching circuit; otherwise, avalanche charge accumulation will occur, generating a "after-pulse" (a false trigger caused by residual charge carriers from the previous avalanche), while simultaneously limiting the detection count rate.
[0003] Existing quenching methods for single-photon detection devices are mainly divided into passive quenching and active quenching: Passive quenching: It relies on the voltage division effect of the resistor to naturally reduce the APD voltage, but its quenching time is long (usually >10ns), which cannot meet the requirements of high-speed detection. Active quenching: After identifying the avalanche signal through the discrimination circuit, the monostable circuit is triggered to output a quenching signal. Its shortest avalanche time is about 1.5ns, but there is still a significant signal delay. This delay will cause the APD avalanche charge to be unable to be released quickly, resulting in a high probability of afterpulse and a limited count rate. It is difficult to adapt to scenarios with strict requirements for "low afterpulse and high count rate" such as quantum communication and high frequency spectral analysis, such as the scheme proposed by F. Acerbi et al. in the IEEE Journal of Quantum Electronics.
[0004] Therefore, there is an urgent need for a free-running single-photon detection scheme that can shorten the quenching delay, suppress the afterpulse, and increase the count rate. Summary of the Invention
[0005] To address at least one of the aforementioned problems, this application proposes a free-running single-photon detection device employing traveling wave quenching to overcome the shortcomings of existing active quenching schemes, such as "large signal delay, high after-pulse rate, and low count rate," thereby achieving avalanche pulse compression at the level of hundreds of ps and expanding the application scenarios of single-photon detection technology.
[0006] According to a first aspect of this application, at least one embodiment of this application provides a free-running single-photon detection device employing traveling wave quenching, comprising: a single-photon avalanche diode for receiving photons and generating an avalanche signal; an initial quenching isolation component connected in parallel with the single-photon avalanche diode for receiving the avalanche signal generated by the single-photon avalanche diode and feeding back a first quenching current to the single-photon avalanche diode to initially lower the avalanche voltage of the single-photon avalanche diode; and at least one stage of amplification quenching component connected in parallel with the initial quenching isolation component for receiving the avalanche signal transmitted by the initial quenching isolation component and amplifying the avalanche signal generated by the single-photon avalanche diode. The avalanche signal is amplified, and a second quenching current is fed back to the single-photon avalanche diode to further reduce the avalanche voltage of the single-photon avalanche diode. The avalanche signal is transmitted in the traveling wave propagation direction in at least one stage of the amplification and quenching component. A quenching signal processing component is connected in parallel with the at least one stage of the amplification and quenching component to receive the avalanche signal transmitted by the at least one stage of the amplification and quenching component and to feed back a final quenching current to the single-photon avalanche diode to stabilize the voltage of the single-photon avalanche diode below the non-avalanche threshold, terminate the avalanche process, and compress the width of the avalanche pulse to a set time level.
[0007] For example, in some embodiments of this application, the initial quenching isolation component includes: a first switching transistor, the drain of which is connected to the cathode of the single-photon avalanche diode, and the source of which is grounded; the first switching transistor is configured to receive the avalanche signal generated by the single-photon avalanche diode and conduct under bias drive to feed back the first quenching current to the single-photon avalanche diode and initially pull down the avalanche voltage of the single-photon avalanche diode; and a first capacitor, one end of which is connected to the gate of the first switching transistor and the other end of which is connected to the anode of the single-photon avalanche diode.
[0008] For example, in some embodiments of this application, the initial quenching isolation component includes: a first switching transistor, the drain of which is connected to the anode of the single-photon avalanche diode, and the source of which is grounded; the first switching transistor is configured to: receive the avalanche signal generated by the single-photon avalanche diode, and conduct under bias drive to feed back the first quenching current to the single-photon avalanche diode, thereby initially lowering the avalanche voltage of the single-photon avalanche diode; and a first capacitor, one end of which is connected to the gate of the first switching transistor, and the other end of which is connected to the cathode of the single-photon avalanche diode.
[0009] For example, in some embodiments of this application, at least one stage of the amplification and quenching component includes: a first amplifying transistor with its source grounded; a second amplifying transistor with its source grounded, the first and second amplifying transistors being used to amplify the avalanche signal transmitted by the initial quenching isolation component; a second switching transistor with its drain connected to the drain of the first switching transistor and its source grounded, the second switching transistor being configured to: receive the avalanche signal amplified by the first and second amplifying transistors, and conduct under bias drive to feed back the second quenching current to the single-photon avalanche diode to further reduce the avalanche voltage of the single-photon avalanche diode; a second capacitor, one end of which is connected to the other end of the first capacitor and the other end of which is connected to the gate of the first amplifying transistor; a third capacitor, one end of which is connected to the drain of the first amplifying transistor and the other end of which is connected to the gate of the second amplifying transistor; a fourth capacitor, one end of which is connected to the drain of the second amplifying transistor and the other end of which is connected to the gate of the second switching transistor; a first resistor, one end of which is connected to the drain of the first amplifying transistor; and a second resistor, one end of which is connected to the drain of the second amplifying transistor and the other end of which is connected to the other end of the first resistor.
[0010] For example, in some embodiments of this application, the free-running single-photon detection device includes multiple stages of the amplification and quenching components, which are cascaded in sequence, wherein: the second capacitor of the first stage amplification and quenching component is connected to the other end of the first capacitor; and the second capacitor of each stage amplification and quenching component is connected to the drain of the second amplifying tube of the previous stage amplification and quenching component.
[0011] For example, in some embodiments of this application, the quenching signal processing component includes: an integrating capacitor, the first input of which is connected to a power supply, the integrating capacitor being used to convert the avalanche signal processed by at least one stage of the amplification and quenching component into a voltage signal; a front-end signal processing chip, the second pin of which is connected to the output of the integrating capacitor, for timing calibration of the voltage signal transmitted by the integrating capacitor; a fifth capacitor, one end of which is connected to the drain of the second amplifying transistor of the amplification and quenching component, and the other end of which is connected to the second input of the integrating capacitor; a sixth capacitor, one end of which is grounded, and the other end of which is connected to the first pin of the front-end signal processing chip; a third resistor, one end of which is connected to the first pin of the front-end signal processing chip, and the other end of which is connected to the third pin of the front-end signal processing chip; and a third switching transistor, the drain of which is connected to the first pin of the third switching transistor. The third switch is connected to the drain of the first switch and grounded. It is configured to receive the voltage signal calibrated by the pre-processing chip and conduct under bias drive, feeding back the final quenching current to the single-photon avalanche diode to stabilize its voltage below the non-avalanche threshold, terminating the avalanche process and compressing the avalanche pulse width to a set time level. A fourth resistor is connected at one end to the gate of the third switch and at the other end to the power supply. A fifth resistor is connected at one end to the gate of the third switch and at the other end to the fourth pin of the pre-processing chip. A seventh capacitor is connected at one end to the fourth pin of the pre-processing chip and at the other end as the output of the free-running single-photon detection device, outputting an avalanche pulse with a width conforming to the set time level.
[0012] For example, in some embodiments of this application, the first switch, the second switch, the third switch, the first amplifier, and the second amplifier all include: gallium nitride high electron mobility transistors, gallium arsenide high electron mobility transistors, indium phosphide high electron mobility transistors, indium gallium arsenide high electron mobility transistors, silicon-based gallium nitride high electron mobility transistors, silicon carbide-based high electron mobility transistors, two-dimensional material high electron mobility transistors, heterojunction bipolar transistors, bipolar junction transistors, field-effect transistors, metal-semiconductor field-effect transistors, metal-insulator-semiconductor heterojunction field-effect transistors, heterojunction field-effect transistors, insulated-gate bipolar transistors, power bipolar junction transistors, tunneling field-effect transistors, and / or organic field-effect transistors.
[0013] For example, in some embodiments of this application, a biasing component is further included, which is connected to the single-photon avalanche diode, the initial quenching isolation component, at least one stage of the amplification quenching component, and the quenching signal processing component, respectively, to provide operating voltage to the single-photon avalanche diode, the initial quenching isolation component, at least one stage of the amplification quenching component, and the quenching signal processing component.
[0014] For example, in some embodiments of this application, the single-photon avalanche diode includes: InGaAs / InP, Si and / or Ge / Si.
[0015] Through the above exemplary embodiments, the free-running single-photon detection device employing traveling wave quenching provided in this application has at least one of the following beneficial effects: Extremely short quenching delay, compressed avalanche pulse: By using traveling wave quenching logic (initial quenching - amplified quenching - final quenching), the processing delay of the avalanche signal is compressed, and the avalanche pulse width is synchronously compressed to the order of hundreds of ps. Low afterpulse, high count rate: Hundreds of ps quenching can quickly release the avalanche charge of the APD, reducing the probability of afterpulse; at the same time, the free operation mode without external clock constraints can achieve a high count rate to meet the requirements of high frequency detection. Strong device compatibility: Switching transistors and amplifying transistors can be selected from various types such as GaN HEMT and GaAs HEMT, and the APD supports InGaAs / Si base, which can be flexibly configured according to the detection band and voltage requirements.
[0016] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description
[0017] The above and other objects, features, and advantages of this application will become more apparent from the detailed description of exemplary embodiments with reference to the accompanying drawings. The drawings described below are merely some embodiments of this application and are not intended to limit the scope of this application.
[0018] Figure 1 A schematic diagram of the overall circuit structure of a free-running single-photon detection device employing traveling wave quenching is shown in an exemplary embodiment. Figure 2 Another embodiment of the overall circuit structure of an exemplary free-running single-photon detection device employing traveling wave quenching is shown; Figure 3 A schematic diagram of an exemplary amplifier tube is shown. Detailed Implementation
[0019] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.
[0020] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.
[0021] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.
[0022] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.
[0023] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.
[0024] Figure 1 A schematic diagram of the overall circuit structure of a free-running single-photon detection device employing traveling wave quenching, as shown in an exemplary embodiment, is illustrated.
[0025] like Figure 1 As shown, the free-running single-photon detection device employing traveling wave quenching includes: a single-photon avalanche diode (APD), an initial quenching isolation component 101, at least one stage of amplification quenching component 102, and a quenching signal processing component 103.
[0026] Among them, the single-photon avalanche diode (APD) is used to operate in Geiger mode, receive incident photons, and convert the single-photon signal into an initial avalanche signal through the avalanche multiplication effect, providing a signal source for subsequent detection.
[0027] According to some embodiments, single-photon avalanche diodes include: InGaAs, Si, Ge / Si, etc.
[0028] The initial quenching isolation component 101 is connected in parallel with the single-photon avalanche diode (APD) to receive the avalanche signal generated by the APD and to feed back the first quenching current to the APD, so as to initially lower the avalanche voltage of the APD and slow down the spread rate of the avalanche effect.
[0029] At least one stage of amplification and quenching component 102 is connected in parallel with the initial quenching and isolation component 101. This component receives the avalanche signal transmitted by the initial quenching and isolation component 101, amplifies the avalanche signal, and feeds back a second quenching current to the single-photon avalanche diode (APD) to further reduce the avalanche voltage of the APD. The avalanche signal propagates in the traveling wave direction within the at least one stage of amplification and quenching component.
[0030] According to some embodiments, the amplification quenching component 102 may include one or more stages. This application uses the example of the amplification quenching component 102 including two stages for illustration, but this application is not limited thereto.
[0031] The quenching signal processing component 103 is connected in parallel with at least one stage amplification quenching component 102 to receive the avalanche signal transmitted by the at least one stage amplification quenching component 102 and feed back the final quenching current to the single-photon avalanche diode APD to stabilize the voltage of the single-photon avalanche diode APD below the non-avalanche threshold, terminate the avalanche process, and compress the width of the avalanche pulse to the set time level.
[0032] The specific circuit structure is as follows: Figure 1 As shown, the initial quenching isolation component 101 includes: a first switching transistor S1 and a first capacitor C1.
[0033] In this configuration, the drain of the first switching transistor S1 is connected to the cathode of the single-photon avalanche diode (APD), and the source is grounded. One end of the first capacitor C1 is connected to the gate of the first switching transistor S1, and the other end is connected to the anode of the APD.
[0034] The first switch S1 is configured to receive the avalanche signal generated by the single-photon avalanche diode APD, and conduct under bias drive to feed back the first quenching current to the single-photon avalanche diode APD, thereby initially lowering the avalanche voltage of the single-photon avalanche diode APD.
[0035] The at least one-stage amplification and quenching component 102 includes: a first amplifying tube A1, a second amplifying tube A2, a second switching tube S2, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, and a second resistor R2.
[0036] The source of the first amplifying transistor A1 is grounded. The source of the second amplifying transistor A2 is grounded. The first and second amplifying transistors A1 and A2 are used to amplify the avalanche signal transmitted by the initial quenching isolation component 101. The drain of the second switching transistor S1 is connected to the drain of the first switching transistor S1, and its source is grounded. One end of the second capacitor C2 is connected to the other end of the first capacitor C1, and the other end is connected to the gate of the first amplifying transistor A1. One end of the third capacitor C3 is connected to the drain of the first amplifying transistor A1, and the other end is connected to the gate of the second amplifying transistor A2. One end of the fourth capacitor C4 is connected to the drain of the second amplifying transistor A2, and the other end is connected to the gate of the second switching transistor S2. One end of the first resistor is connected to the drain of the first amplifying transistor A1. One end of the second resistor R2 is connected to the drain of the second amplifying transistor A2, and the other end is connected to the other end of the first resistor R1.
[0037] According to some embodiments, considering the positive and negative pulses of the avalanche signal, the amplifying transistor should coordinate with the switching transistor to take into account the correct direction of the avalanche signal. For example, the first amplifying transistor A1 and the second amplifying transistor A2 of this application are cascaded to amplify the amplitude of the avalanche signal while maintaining the polarity of the avalanche signal.
[0038] The second switch S2 is configured to receive the avalanche signal amplified by the first amplifier A1 and the second amplifier A2, and conduct under bias drive to feed back the second quenching current to the single-photon avalanche diode APD, so as to further reduce the avalanche voltage of the single-photon avalanche diode APD.
[0039] According to some embodiments, considering the overshoot and dynamic characteristics caused by the blocking capacitor, the conduction time between the first switch S1 and the second switch S2 can be set to overlap or the interval can be as small as possible to avoid the adverse effects of the blocking capacitor on quenching.
[0040] According to the example embodiment, in the case of a multi-stage amplification and quenching assembly, the multi-stage amplification and quenching assemblies are cascaded sequentially, wherein: the second capacitor of the first-stage amplification and quenching assembly is connected to the other end of the first capacitor; the second capacitor of each stage amplification and quenching assembly is connected to the drain of the second amplifying tube of the previous stage amplification and quenching assembly. The avalanche signal is transmitted in the multi-stage amplification and quenching assembly according to the "traveling wave propagation direction" (i.e., from the first stage amplification and quenching assembly to the next stage amplification and quenching assembly, the avalanche signal is transmitted and amplified stage by stage), forming a progressive "amplification-quenching" logic, avoiding signal delay superposition.
[0041] like Figure 1As shown, the circuit structure of the second-stage amplification and quenching component is the same as that of the first-stage amplification and quenching component, and its working principle is also the same. Two amplifying transistors further amplify the avalanche signal while maintaining its polarity. The switching transistor receives the amplified avalanche signal and, powered by the bias component, enhances and quenches the avalanche state of the single-photon avalanche diode (APD) based on the avalanche signal.
[0042] The quenching signal processing component 103 includes: an integrating capacitor CINT, a front-end signal processing chip 1031, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a third switching transistor S3.
[0043] The avalanche signal is converted into a voltage signal by the integrating capacitor CINT, which is connected to the power supply after being processed by at least one stage of amplification and quenching components. Pin 2 of the pre-amplifier chip 1031 is connected to the output of the integrating capacitor CINT, used for timing calibration of the voltage signal transmitted by CINT to eliminate delay deviations in each stage of the components and ensure the timing accuracy of the avalanche signal. One end of the fifth capacitor C5 is connected to the drain of the second amplifying transistor A2 of the amplification and quenching component, and the other end is connected to the second input of the integrating capacitor CINT. One end of the sixth capacitor C6 is grounded, and the other end is connected to pin 1 of the pre-amplifier chip 1031. One end of the third resistor R3 is connected to pin 1 of the pre-amplifier chip 1031, and the other end is connected to pin 3 of the pre-amplifier chip 1031. The drain of the third switching transistor S3 is connected to the drain of the first switching transistor S1, and its source is grounded. One end of the fourth resistor R4 is connected to the gate of the third switching transistor S3, and the other end is connected to the power supply. One end of the fifth resistor R5 is connected to the gate of the third switch S3, and the other end is connected to pin 4 of the pre-amplifier signal processing chip 1031. One end of the seventh capacitor C7 is connected to pin 4 of the pre-amplifier signal processing chip 1031, and the other end serves as the output of the free-running single-photon detector, outputting an avalanche pulse with a width conforming to a set time order for subsequent system reading.
[0044] The third switch S3 is configured to receive the voltage signal calibrated by the pre-processing chip 1031 and conduct under bias drive, feeding back the final quenching current to the single-photon avalanche diode (APD) to stabilize the voltage of the APD below the non-avalanche threshold, terminating the avalanche process and compressing the width of the avalanche pulse to a set time level. For example, the width of the avalanche pulse can be compressed to the order of hundreds of ps. This application uses this as an example only, but is not limited thereto.
[0045] According to an example embodiment, the free-running single-photon detection device also includes a biasing component 104.
[0046] like Figure 1 As shown, the biasing component 104 includes a positive bias terminal (V_Bias_Positive) and a negative bias terminal (V_Bias_Negative). The biasing component 104 is connected to the single-photon avalanche diode (APD), the initial quenching isolation component 101, at least one stage amplification quenching component 102, and the quenching signal processing component 103, respectively, to provide suitable operating voltages to these components. The biasing component 104 provides a reverse bias to the APD to maintain Geiger mode, provides the necessary voltage for each switching transistor to conduct, and provides a static operating bias to each amplifying transistor. The voltage can be flexibly adjusted via the positive and negative bias terminals to adapt to different device selection requirements.
[0047] According to some embodiments, the first switching transistor, the second switching transistor, the third switching transistor, the first amplifying transistor, and the second amplifying transistor are all transistors with switching functions, including: gallium nitride high electron mobility transistors (GaN HEMTs), gallium arsenide high electron mobility transistors (GaAs HEMTs), indium phosphide high electron mobility transistors (InP HEMTs), indium gallium arsenide high electron mobility transistors (InGaAs HEMTs), silicon-based gallium nitride high electron mobility transistors (GaN-on-Si HEMTs), silicon carbide-based high electron mobility transistors (SiC-GaN HEMTs), two-dimensional material (graphene, MoS2, black phosphorus) high electron mobility transistors (HEMTs); heterojunction bipolar transistors (HBTs), such as silicon-germanium (SiGe) heterojunction bipolar transistors (SiGe). HBTs include bipolar junction transistors (BJTs), field-effect transistors (MOSFETs), metal-semiconductor field-effect transistors (MESFETs), metal-insulator-semiconductor heterojunction field-effect transistors (MISHFETs), heterojunction field-effect transistors (HJFETs), insulated gate bipolar transistors (IGBTs), power bipolar junction transistors (PowerBJTs), tunneling field-effect transistors (TFETs), organic field-effect transistors (OFETs), etc., which can adapt to different operating voltages. The operating voltage can be set through V_Bias_Positive and V_Bias_Negative.
[0048] Among them, GaN HEMT has the highest quenching voltage, which means it has the strongest quenching effect.
[0049] This application Figure 1 The circuit structure is explained using field-effect transistors as the switching transistor and the amplifying transistor. If... Figure 1If the switching transistor and the amplifying transistor are transistors, then the gate of the field-effect transistor corresponds to the base of the transistor, the source of the field-effect transistor corresponds to the emitter of the transistor, and the drain of the field-effect transistor corresponds to the collector of the transistor, and so on.
[0050] According to the example embodiment, the switching times of the first, second, and third switching transistors, as well as the delay times of the first and second amplifying transistors, need to be matched to achieve a good quenching function. Furthermore, the avalanche signals at the gates of the first, second, and third switching transistors increase in strength; therefore, the switching gain at the gates of the first, second, and third switching transistors should decrease in strength to ensure that the quenching current is within a reasonable range.
[0051] According to some embodiments, any of the amplifying tubes in this application can also adopt a distributed amplifier topology, such as... Figure 3 As shown, the classic structure of a distributed amplifier uses field-effect transistors (FETs) as the core amplification unit. Multiple FETs are connected to their gates and drains via two parallel artificial transmission lines (Gate Transmission Line RFin and Drain Transmission Line RFout), forming a distributed network of "transmission line series amplification transistors." The input signal synchronously triggers all FETs along the gate transmission line, and the amplified signals from each transistor are superimposed on the drain transmission line for output. This multi-transistor parallel amplification compensates for insufficient gain in a single transistor, while the transmission line characteristics expand the bandwidth. However, to reduce time delay, it is necessary to ensure phase velocity matching between the gate and drain lines (to avoid delay superposition caused by asynchronous signal transmission). Additionally, adding a low-frequency AC terminator optimizes gain flatness, indirectly reducing frequency-dependent delay fluctuations.
[0052] Figure 2 This illustrates yet another embodiment of the overall circuit structure of an exemplary free-running single-photon detection device employing traveling wave quenching.
[0053] Figure 2 The overall circuit structure of the free-running single-photon detector shown is similar to Figure 1The overall circuit structure of the free-running single-photon detection device shown is basically the same, except that the single-photon avalanche diode (APD) is reversed, and the connection order of the switching transistors of the initial quenching isolation component 101, at least one stage amplification quenching component 102, and quenching signal processing component 103 is also changed. Specifically, the source of the first switching transistor S1 of the initial quenching isolation component 101 is connected to the anode of the single-photon avalanche diode (APD), and the drain is grounded. One end of the first capacitor C1 is connected to the gate of the first switching transistor S1, and the other end is connected to the cathode of the single-photon avalanche diode (APD). The source of the second switching transistor S2 of the at least one stage amplification quenching component 102 is connected to the anode of the single-photon avalanche diode (APD), and the drain is grounded. The source of the third switching transistor S3 of the quenching signal processing component 103 is connected to the anode of the single-photon avalanche diode (APD), and the drain is grounded.
[0054] Figure 2 The overall circuit structure of the free-running single-photon detector shown is similar to Figure 1 The overall circuit structure of the free-running single-photon detection devices shown is basically the same, and the core working principle is exactly the same. The only difference lies in the connection method of the single-photon avalanche diode (APD) and the corresponding terminal of the quenching current: Figure 1 In this circuit, the drains of the first, second, and third switching transistors are all connected to the cathode of the APD. The avalanche voltage is lowered and the avalanche process is terminated by feeding a quenching current back to the APD cathode; this is known as cathode quenching. Figure 2 In this configuration, the APD is reverse-connected, and the sources of the first, second, and third switching transistors are all connected to the anode of the APD. A quenching current is fed back to the anode of the APD to lower the avalanche voltage and terminate the avalanche process, i.e., anode quenching. Therefore, this application addresses... Figure 2 The specific working process of the device shown will not be described in detail.
[0055] The following describes the implementation process of the free-running single-photon detection device of this application in a specific scenario, in order to... Figure 1 Taking the free-running single-photon detector shown as an example, such as Figure 1 As shown: 1. Bias configuration stage: The bias component provides the working voltage for each component - the single-photon avalanche diode APD obtains a 26V reverse bias (higher than the breakdown voltage), each switching transistor obtains a drain bias and a gate bias, each amplifying transistor obtains a drain bias, and the free-running single-photon detection device enters the detection state.
[0056] 2. Avalanche signal generation stage: A single near-infrared photon is incident on the photosensitive region of the single-photon avalanche diode (APD), exciting the initial electron-hole pair. This charge carrier is accelerated in a strong electric field of 26V, triggering the avalanche multiplication effect. The single-photon avalanche diode (APD) outputs an initial avalanche signal with an amplitude of about 50μA and a width of about 1ns.
[0057] 3. Initial Quenching Stage: The initial avalanche signal is coupled to the gate of the first switching transistor through the first capacitor, triggering the first switching transistor to turn on. The first switching transistor feeds back the first quenching current to the single-photon avalanche diode (APD), and the voltage of the single-photon avalanche diode (APD) drops from 26V to 24V within 50ps, initially suppressing avalanche propagation.
[0058] 4. Traveling Wave Amplification and Quenching Stage: After initial quenching, the avalanche signal is coupled to the first amplifying transistor through the second capacitor, amplified to 1V by the first amplifying transistor, and then coupled to the second amplifying transistor through the third capacitor, further amplified to 5V; the 5V amplified signal is coupled to the gate of the second switching transistor through the fourth capacitor, triggering the second switching transistor to conduct and feeding back the second quenching current; the voltage of the single-photon avalanche diode APD drops from 24V to 22V within 30ps, and the avalanche effect is significantly reduced; the second-stage amplification and quenching component repeats the above process, amplifying the avalanche signal to 5V again, triggering the second switching transistor of the second stage to conduct and feeding back the third quenching current, and the voltage of the single-photon avalanche diode APD drops to 20V within 30ps (below the breakdown voltage of 25V).
[0059] 5. Final Quenching and Signal Output Stage: The signal after second-stage amplification and quenching is coupled to the integrating capacitor CINT through the fifth capacitor. The integrating capacitor CINT converts the signal into a voltage signal, which is then transmitted to the front-end signal processing chip. The front-end signal processing chip performs timing calibration on the voltage signal. The calibrated voltage signal is coupled to the gate of the third switch through the fifth resistor, triggering the third switch to turn on. The third switch feeds back the final quenching current, and the voltage of the single-photon avalanche diode APD stabilizes to 18V (below the non-avalanche threshold) within 20ps, completely terminating the avalanche process. At the same time, the calibrated signal is output through the seventh capacitor, resulting in an avalanche pulse with a width of approximately 80ps and an amplitude of approximately 3V, which is then read by the subsequent quantum communication system.
[0060] 6. Reset phase: Each switch returns to the off state, the bias component maintains the 26V reverse bias of the single-photon avalanche diode APD, and the device returns to the detection state, waiting for the next incident photon.
[0061] Through the above example embodiments, the free-running single-photon detection device using traveling wave quenching provided by this application has the following beneficial effects: This application can achieve extremely short quenching delay and compress avalanche pulses. By using the traveling wave quenching logic of "initial quenching - amplification quenching - final quenching", the processing delay of avalanche signals is effectively compressed, and the avalanche pulse width is reduced to the order of hundreds of ps. Secondly, this application can achieve the dual advantages of low afterpulse and high count rate. The fast quenching at the order of hundreds of ps can release the avalanche charge of the single-photon avalanche diode (APD) in time, significantly reducing the probability of afterpulse. At the same time, the free-running mode without external clock constraints can achieve a high count rate, which fully meets the needs of high-frequency detection scenarios. In addition, the switching transistor and amplifying transistor of this application can be selected from various types such as gallium nitride high electron mobility transistor (GaN HEMT) and gallium arsenide high electron mobility transistor (GaAsHEMT), and the APD supports InGaAs-based, Si-based and / or Ge / Si, which can be flexibly configured according to the actual detection band and voltage requirements.
[0062] It should be clearly understood that this application describes how specific examples are formed and used, but this application is not limited to any details of these examples. Rather, based on the teachings of the disclosure of this application, these principles can be applied to many other embodiments.
[0063] Furthermore, it should be noted that the above figures are merely illustrative representations of the processes included in the method according to exemplary embodiments of this application, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.
[0064] Exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, arrangements, or implementation methods described herein; rather, this application is intended to cover various modifications and equivalent arrangements that fall within the objectives and scope of the appended claims.
Claims
1. A free-running single-photon detection device employing traveling wave quenching, characterized in that, include: Single-photon avalanche diode is used to receive photons and generate avalanche signals; An initial quenching isolation component is connected in parallel with the single-photon avalanche diode to receive the avalanche signal generated by the single-photon avalanche diode and to feed back a first quenching current to the single-photon avalanche diode to initially lower the avalanche voltage of the single-photon avalanche diode. At least one amplification and quenching component is connected in parallel with the initial quenching and isolation component to receive the avalanche signal transmitted by the initial quenching and isolation component, amplify the avalanche signal, and feed back a second quenching current to the single-photon avalanche diode to further reduce the avalanche voltage of the single-photon avalanche diode. The avalanche signal is transmitted in the traveling wave propagation direction in at least one amplification and quenching component. A quenching signal processing component is connected in parallel with at least one of the amplification and quenching components to receive the avalanche signal transmitted by the at least one amplification and quenching component and to feed back the final quenching current to the single-photon avalanche diode, so as to stabilize the voltage of the single-photon avalanche diode below the non-avalanche threshold, terminate the avalanche process, and compress the width of the avalanche pulse to a set time level.
2. The free-running single-photon detection device as described in claim 1, characterized in that, The initial quenching isolation component includes: The first switching transistor has its drain connected to the cathode of the single-photon avalanche diode and its source grounded. The first switching transistor is configured as follows: The avalanche signal generated by the single-photon avalanche diode is received and turned on under bias drive, and the first quenching current is fed back to the single-photon avalanche diode to initially pull down the avalanche voltage of the single-photon avalanche diode; The first capacitor has one end connected to the gate of the first switching transistor and the other end connected to the anode of the single-photon avalanche diode.
3. The free-running single-photon detection device as described in claim 1, characterized in that, The initial quenching isolation component includes: The first switching transistor has its drain connected to the anode of the single-photon avalanche diode and its source grounded. The first switching transistor is configured as follows: The avalanche signal generated by the single-photon avalanche diode is received and turned on under bias drive, and the first quenching current is fed back to the single-photon avalanche diode to initially pull down the avalanche voltage of the single-photon avalanche diode; The first capacitor has one end connected to the gate of the first switching transistor and the other end connected to the cathode of the single-photon avalanche diode.
4. The free-running single-photon detection device as described in claim 2 or 3, characterized in that, At least one of the amplification and quenching components includes: The first amplifier tube has its source grounded; The second amplifying transistor has its source grounded. The first and second amplifying transistors are used to amplify the avalanche signal transmitted by the initial quenching isolation component. The second switching transistor has its drain connected to the drain of the first switching transistor, and its source grounded. The second switching transistor is configured as follows: The avalanche signal amplified by the first and second amplifier tubes is received and turned on under bias drive to feed back the second quenching current to the single-photon avalanche diode, so as to further reduce the avalanche voltage of the single-photon avalanche diode; The second capacitor has one end connected to the other end of the first capacitor and the other end connected to the gate of the first amplifier tube. The third capacitor has one end connected to the drain of the first amplifier tube and the other end connected to the gate of the second amplifier tube. The fourth capacitor has one end connected to the drain of the second amplifier transistor and the other end connected to the gate of the second switch transistor. The first resistor has one end connected to the drain of the first amplifier tube; The second resistor has one end connected to the drain of the second amplifier tube and the other end connected to the other end of the first resistor.
5. The free-running single-photon detection device as described in claim 4, characterized in that, The free-running single-photon detection device includes multiple stages of the aforementioned amplification and quenching components, which are cascaded sequentially, wherein: The second capacitor of the amplification and quenching component in the first stage is connected to the other end of the first capacitor; The second capacitor of each stage of the amplification and quenching component is connected to the drain of the second amplifying tube of the previous stage of the amplification and quenching component.
6. The free-running single-photon detection device as described in claim 4, characterized in that, The quenching signal processing component includes: An integrating capacitor, the first input terminal of which is connected to a power supply, is used to convert the avalanche signal after being processed by at least one stage of the amplification and quenching component into a voltage signal. The second pin of the front-end signal processing chip is connected to the output terminal of the integrating capacitor, and is used to perform timing calibration on the voltage signal transmitted by the integrating capacitor. The fifth capacitor has one end connected to the drain of the second amplifying tube of the amplification and quenching component, and the other end connected to the second input terminal of the integrating capacitor. The sixth capacitor has one end grounded and the other end connected to the first pin of the front-end signal processing chip; The third resistor has one end connected to the first pin of the front-end signal processing chip and the other end connected to the third pin of the front-end signal processing chip. The third switching transistor has its drain connected to the drain of the first switching transistor and its source grounded. The third switching transistor is configured as follows: The system receives the voltage signal calibrated by the front-end signal processing chip and turns it on under bias drive to feed back the final quenching current to the single-photon avalanche diode, so as to stabilize the voltage of the single-photon avalanche diode below the non-avalanche threshold, terminate the avalanche process, and compress the width of the avalanche pulse to a set time level. The fourth resistor has one end connected to the gate of the third switching transistor and the other end connected to the power supply. The fifth resistor has one end connected to the gate of the third switching transistor and the other end connected to the fourth pin of the front-end signal processing chip. The seventh capacitor has one end connected to the fourth pin of the pre-stage signal processing chip, and the other end serves as the output terminal of the free-running single-photon detection device, outputting an avalanche pulse with a width conforming to the set time order.
7. The free-running single-photon detection device as described in claim 6, characterized in that, The first switching transistor, the second switching transistor, the third switching transistor, the first amplifying transistor, and the second amplifying transistor all include: Gallium nitride high electron mobility transistor, gallium arsenide high electron mobility transistor, indium phosphide high electron mobility transistor, indium gallium arsenide high electron mobility transistor, silicon-based gallium nitride high electron mobility transistor, silicon carbide-based high electron mobility transistor, two-dimensional material high electron mobility transistor, heterojunction bipolar transistor, bipolar junction transistor, field-effect transistor, metal-semiconductor field-effect transistor, metal-insulator-semiconductor heterojunction field-effect transistor, heterojunction field-effect transistor, insulated gate bipolar transistor, power bipolar junction transistor, tunneling field-effect transistor and / or organic field-effect transistor.
8. The free-running single-photon detection device as described in claim 1, characterized in that, Also includes: A biasing component is connected to the single-photon avalanche diode, the initial quenching isolation component, at least one stage of the amplification quenching component, and the quenching signal processing component, respectively, to provide operating voltage to the single-photon avalanche diode, the initial quenching isolation component, at least one stage of the amplification quenching component, and the quenching signal processing component.
9. The free-running single-photon detection device as described in claim 1, characterized in that, The single-photon avalanche diode includes: InGaAs / InP, Si and / or Ge / Si.