Quantum entropy source control system and control method thereof

Abstract

The invention discloses a quantum entropy source control system and a control method thereof, and belongs to the technical field of entropy sources and random number generators. The control system monitors the environment temperature in real time by introducing an environment temperature sensor, and performs temperature adaptability adjustment on the output light intensity of an LED light source in an entropy source by using a fuzzy PID algorithm; the light intensity irradiated on the surface of the photoelectric detector is stable and is always maintained in a reasonable interval range; moreover, the system is high in real-time response speed, almost has no overshoot, accurately controls the light intensity, and improves the stability of the output light intensity of the entropy source. The fuzzy PID control algorithm can realize light intensity adaptive adjustment, the output light intensity stability is good, the control precision is high, and finally the entropy source outputs an original random sequence with good randomness.

Description

Technical Field

[0001] The present invention belongs to the technical field of entropy source and random number generator, and in particular relates to a quantum entropy source control system and a control method thereof. Background Art

[0002] Entropy is a physical quantity that measures the degree of disorder in a system and is used to characterize characteristics such as disorder and randomness. The entropy source is the source of unpredictable data flow. By collecting and quantifying the uncertainty in the event, the original random sequence is obtained. The entropy source is the core component of the random number generator, which is widely used in many fields such as cryptography and quantum communication.

[0003] Common entropy sources mainly include traditional physical noise entropy sources and quantum noise entropy sources. Traditional physical noise entropy sources mainly include thermal noise entropy sources and phase jitter noise entropy sources. The principle is to use the uncertainty of the physical process in the circuit to obtain a random source sequence. The quantum noise entropy source is an entropy source based on photon noise. It prepares and measures the corresponding quantum state according to the principle of quantum physics and outputs the original random sequence. The randomness of the quantum entropy source is based on the intrinsic characteristics of quantum physics. It is a true random number entropy source. The device that generates random numbers based on the quantum entropy source is called a quantum random number generator. Common quantum entropy sources are divided according to the principle, mainly including single photon entropy source, amplified spontaneous radiation entropy source and spontaneous radiation entropy source, etc. The corresponding technical solutions are branch path scheme entropy source, amplified spontaneous radiation noise entropy source and phase noise entropy source.

[0004] At present, the most studied quantum entropy source is a multi-photon state measurement scheme. Its principle is that the number of photons collected by the photodetector in multiple identical unit times conforms to the random distribution. The implementation method of this scheme is to control the light source to emit weak light to the surface of the photodetector, and after photoelectric conversion and post-processing, output the original random sequence of digital quantities. The commonly used quantum entropy source based on the multi-photon state measurement scheme needs to control the stability of the light intensity output by the light source to ensure that the light intensity incident on the surface of the subsequent photodetector is maintained in a reasonable threshold range as much as possible (that is, the light intensity cannot be too strong or too weak), so that the number of photons received on the surface of the photodetector conforms to the Poisson random distribution, and the randomness of the original random sequence output by the entropy source is ensured based on the randomness of the detected photons. If the output light intensity of the entropy source is unstable, the light intensity irradiated on the surface of the photodetector will vary greatly, resulting in the phenomenon that the photodetector is saturated or no photons are detected (that is, the light intensity exceeds the reasonable threshold range), which in turn causes the randomness of the original random sequence output by the entropy source to deteriorate. Therefore, the stability of the light intensity determines the randomness of the original random sequence output by the quantum entropy source based on the multi-photon state measurement scheme. Summary of the invention

[0005] The purpose of the present invention is to provide a quantum entropy source control system and a control method thereof, so as to solve the problem that the output light intensity of the quantum entropy source based on the multi-photon state measurement scheme in the prior art is unstable, resulting in large changes in the light intensity irradiated to the surface of the photodetector, causing the photodetector to be saturated or unable to detect any photons (that is, the light intensity exceeds a reasonable threshold range), thereby causing the randomness of the original random sequence output by the entropy source to deteriorate.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A quantum entropy source control system, comprising an LED light source, a photodetector array, an analog-to-digital converter, a temperature sensor and a controller;

[0008] The LED light source is used to emit the weak light required by the entropy source;

[0009] The photodetector array is used to respond to the weak light signal generated by the LED light source and convert it into an electrical signal;

[0010] The analog-to-digital converter is used to convert the analog electrical signal detected by the photodetector array into a digital electrical signal, which is then transmitted to the subsequent controller for LED light intensity sampling;

[0011] The temperature sensor is used to monitor the ambient temperature and transmit the temperature value to the controller;

[0012] The controller is used to obtain the temperature value of the ambient temperature sensor and the light intensity value output by the photoelectric detector in real time, drive and adjust the LED light source to emit the light intensity required by the system in real time through the fuzzy PID algorithm, and finally output the original random sequence.

[0013] As a further solution of the present invention, the LED light source is a common LED light source or an LED laser light source.

[0014] As a further solution of the present invention, the photodetector array is an integrated device of multiple photodetectors of the same type.

[0015] As a further solution of the present invention, the temperature sensor has an accuracy of ±0.01°C.

[0016] As a further solution of the present invention, the controller is a field programmable gate array FPGA or a complex programmable logic device CPLD.

[0017] As a further solution of the present invention, a control method according to the above-mentioned quantum entropy source control system includes the following steps:

[0018] The quantum entropy source control system is powered on and initialized;

[0019] The ambient temperature sensor obtains the real-time ambient temperature value and sets the target light intensity value according to the ambient temperature and light intensity change relationship table stored in the controller;

[0020] The system uses fuzzy PID control algorithm to drive the LED to emit light according to the target light intensity value;

[0021] The system detects the actual output light intensity of the LED light source through a photodetector array and transmits the actual value of the light intensity to the control system in real time;

[0022] The control system determines whether the light intensity meets the target setting value. If it meets and is stable, the entropy source outputs the original random sequence. Otherwise, it returns to continue using the fuzzy PID algorithm to adjust the LED output light intensity until the ideal light intensity is reached.

[0023] As a further solution of the present invention, the method of using a fuzzy PID control algorithm in the controller to drive the LED to emit light comprises the following steps:

[0024] The control system uses the error e(t) between the actual LED output light intensity and the target light intensity and the error change rate de / dt as the input of the fuzzy PID controller, the corrected Kp, Ki and Kd as the direct control output of the system, and the LED light source driving voltage u(t) as the indirect control output;

[0025] According to the error e(t) and the error change rate de / dt, the PID control parameters are adjusted in real time through the fuzzy controller, and then the LED drive voltage u(t) is adjusted in real time until the light intensity is within the target temperature threshold range.

[0026] Beneficial effects of the present invention:

[0027] 1. The present invention can adjust the light intensity fluctuation of the LED output light intensity in the quantum entropy source caused by temperature change in real time, maintain the light intensity stability of the entropy source, and finally make the entropy source output an original random sequence with better randomness.

[0028] 2. The present invention adopts fuzzy PID algorithm for light intensity control, which can automatically adjust the P, I, and D parameter values. The system has a fast real-time response speed, almost no overshoot, and can accurately control the light intensity, thereby improving the stability of the light intensity output by the entropy source. The fuzzy PID control algorithm can realize adaptive light intensity adjustment, and the output light intensity has good stability and high control accuracy, which ultimately makes the entropy source output an original random sequence with good randomness.

[0029] 3. The present invention solves the problem of the change of light intensity of the quantum entropy source with temperature and the stability of light intensity, so that the quantum entropy source can operate in a wider ambient temperature range (that is, the temperature sensitivity of the entropy source is reduced, and better stability can be achieved in the temperature range of -40°C to +85°C), and the randomness of the output original random number sequence is better.

[0030] 4. The control system and control method of the present invention are simple and easy to implement, the control system is easy to implement and integrate, can be industrialized, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] Figure 1 It is the relationship between the luminous intensity of LED light source and the ambient temperature;

[0033] Figure 2 It is a block diagram of the quantum entropy source control system of the present invention;

[0034] Figure 3 It is a principle block diagram of the quantum entropy source control method of the present invention;

[0035] Figure 4 This is the working flow chart of quantum entropy source control system. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Depend on Figure 1 It can be seen that the light intensity of the LED light source changes with the change of the ambient temperature, that is, the light intensity decreases with the increase of temperature, and its curve is not a linear relationship. For a quantum entropy source that works normally at room temperature, when the ambient temperature changes to the high temperature zone, the LED output light intensity becomes relatively weak, which may cause the photodetector to detect no photons; when the ambient temperature changes to the low temperature zone, the LED output light intensity becomes relatively strong, which may cause the photodetector to receive too many photons, resulting in saturation of the detector's photoelectric response ability. Regardless of whether the LED output light intensity becomes stronger or weaker, as long as the LED output light intensity in the quantum entropy source is unstable, it may eventually cause the randomness of the output original random sequence to deteriorate. Therefore, the control system of the present invention monitors the ambient temperature in real time by introducing an ambient temperature sensor, and uses a fuzzy PID algorithm to adjust the temperature adaptability of the output light intensity of the LED light source in the entropy source, so that the light intensity irradiated to the surface of the photodetector is stable and always maintained within a reasonable range (the photodetector within the threshold range is neither saturated nor close to the background noise, and the randomness of the original random sequence output by the entropy source is the best).

[0038] A quantum entropy source control system, such as Figure 2As shown, it includes an LED light source, a photodetector array, an analog-to-digital converter, a temperature sensor, and a controller;

[0039] The LED light source is used to emit the weak light required by the entropy source, which can be a common LED light source or an LED laser light source;

[0040] The photodetector array is used to respond to the weak light signal generated by the LED light source and convert it into an electrical signal;

[0041] Specifically, the photodetector array is an integrated device of multiple photodetectors of the same type (the integration of multiple photodetectors can effectively improve the output bit rate of the original random sequence of the entropy source), and a single photodetector includes an avalanche photodiode, an image sensor, and a phototransistor, etc.;

[0042] The analog-to-digital converter is used to convert the analog electrical signal detected by the photodetector array into a digital electrical signal, which is then transmitted to the subsequent controller for LED light intensity sampling; specifically, the photodetector array converts the number of photons received per unit time into the number of electrons, and the analog-to-digital converter converts the sampled number of electrons into a digital electrical signal and outputs it to the controller;

[0043] The temperature sensor is used to monitor the ambient temperature and transmit the temperature value to the controller;

[0044] Preferably, the temperature sensor is an internally integrated high-precision platinum resistor PT100 or PT1000 temperature sensor with an accuracy of up to ±0.01°C;

[0045] The controller is the control unit of the entropy source, which is used to obtain the temperature value of the ambient temperature sensor and the light intensity value output by the photoelectric detector in real time, drive and adjust the LED light source to emit the required light intensity of the system in real time through the fuzzy PID algorithm, and finally output the original random sequence (a random sequence containing only 0 and 1 and their combinations);

[0046] The controller is a field programmable gate array (the FPGA has an internal integrated flash to ensure an information security environment) or a complex programmable logic device (CPLD).

[0047] like Figure 4 As shown, when the control system works:

[0048] The quantum entropy source control system is powered on and initialized;

[0049] The ambient temperature sensor obtains the real-time ambient temperature value and sets the target light intensity value according to the ambient temperature and light intensity change relationship table stored in the controller;

[0050] The system uses fuzzy PID control algorithm to drive the LED to emit light according to the target light intensity value;

[0051] The system detects the actual output light intensity of the LED light source through a photodetector array and transmits the actual value of the light intensity to the control system in real time;

[0052] The control system determines whether the light intensity meets the target setting value. If it meets and is stable, the entropy source outputs the original random sequence. Otherwise, it returns to continue using the fuzzy PID algorithm to adjust the LED output light intensity until the ideal light intensity is reached.

[0053] The control system can reduce the temperature sensitivity of the quantum entropy source and enable the quantum entropy source to generate an original random sequence with better randomness.

[0054] The controller adopts fuzzy PID algorithm to perform light intensity stability control, which can effectively improve the light intensity responsiveness and stability of the system.

[0055] like Figure 3 As shown, the control system uses the error (e(t)) between the actual LED output light intensity and the target light intensity and the error change rate (de / dt) as the input of the fuzzy PID controller, the corrected Kp, Ki and Kd as the direct control output of the system, and the LED light source driving voltage u(t) as the indirect control output.

[0056] When the system is working, the PID control parameters are adjusted in real time through the fuzzy controller according to the light intensity error and the error change rate, and then the LED driving voltage u(t) is adjusted in real time (the LED driving voltage determines the intensity of its radiated light intensity) until the ideal light intensity is obtained (that is, the light intensity is within the target temperature threshold range).

[0057] Specific:

[0058] Assume the ambient temperature is T a At this time, the entropy source control system drives the LED to emit the light intensity required by the system, which is P s , the actual light intensity of the system is P a , the entropy source control system is based on the required light intensity P s and the actual light intensity P a The error e(t) (i.e. e(t) = P s -P a ) and the error change rate de / dt are used as the input of the fuzzy PID controller, with ΔK p , ΔK i and ΔK d As the output of the fuzzy controller, the fuzzy subset and fuzzy domain are determined based on experience, and then the fuzzy assignment table is established using the triangular function as the membership function of the input and output of the fuzzy controller;

[0059] In order to achieve the system's rapid response capability and output light intensity stability and accuracy, based on actual control experience, the system fuzzy control rule is: when the system light intensity error e(t) is large, no matter how the light intensity error change rate de / dt changes, in order to improve the system's rapid response capability, the controller's ΔK p Take the maximum value, ΔK i and ΔK d Take the minimum value; when the light intensity deviation e(t) and the error change rate de / dt are moderate, in order to control the overshoot and take into account the response speed, ΔK should be reduced p , appropriately increase ΔK i and ΔK d When the light intensity deviation e(t) is small, in order to increase the system stability, when the error change rate de / dt decreases, ΔK should be reduced. p , increase ΔK i and ΔK d , when the error change rate de / dt increases, ΔK should be reduced p and ΔK d , increase ΔK i .

[0060] The system establishes the output ΔK according to the fuzzy control rules p , ΔK i and ΔK d The fuzzy rule table is constructed, and the center of gravity method is used to establish the fuzzy controller output parameter ΔK p , ΔK i and ΔK d A fuzzy control query table is generated and stored in the controller;

[0061] The system automatically queries the fuzzy query table inside the controller according to the actual control situation, and then calculates the value based on the proportional factor and ΔK p , ΔK i and ΔK d The values ​​of Kp, Ki and Kd are adjusted according to the value of , and finally the adjusted P, I, D parameters (Kp, Ki and Kd) are applied to the PID controller. The output of the PID controller is u(t) (u(t) is a function of Kp, Ki and Kd). The voltage u(t) is the real-time driving voltage of the LED, which directly determines the intensity and stability of the entropy source light intensity.

[0062] When the ambient temperature changes, the system will automatically set the required light intensity according to the ambient temperature change (keeping the entropy source light intensity always within a reasonable threshold range). The control system will use the fuzzy PID control algorithm to automatically readjust the PID control parameters (Kp, Ki and Kd) based on the error and error change rate between the new required light intensity and the actual light intensity, and then adjust the LED drive voltage u(t) value in real time. The real-time drive voltage u(t) determines the intensity and stability of the entropy source light intensity. Therefore, the entropy source light intensity can be adaptively adjusted in real time as the ambient temperature changes, and the real-time response speed of the system can be improved, the overshoot can be reduced, and the stability of the entropy source light intensity can be increased.

[0063] The fuzzy PID control method can improve the light intensity response speed and stability of the quantum entropy source and ensure the randomness of the original random sequence output by the entropy source.

[0064] When the quantum entropy source is working, the controller outputs voltage to drive the LED light source to emit weak light; the weak light irradiates the surface of the photodetector array, and is sampled by the post-stage analog-to-digital converter, which converts the number of photons responded by the photodetector into digital electrical signals and transmits them to the field programmable logic gate array or complex programmable logic device;

[0065] The field programmable logic gate array or complex programmable logic device obtains the light intensity error and error change rate by reading the digital value of the light intensity conversion, and then adjusts the LED drive voltage in real time through the fuzzy PID algorithm to ensure the stability of the LED output light intensity. The LED light intensity in the entropy source is stable, so that the original random sequence output by the entropy source has good randomness and stability.

[0066] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A quantum entropy source control system, characterized in that: It includes an LED light source, a photodetector array, an analog-to-digital converter, a temperature sensor, and a controller; The LED light source is used to emit the weak light required by the entropy source; The photodetector array is used to respond to the weak light signal generated by the LED light source and convert it into an electrical signal; The analog-to-digital converter is used to convert the analog electrical signal detected by the photodetector array into a digital electrical signal, which is then transmitted to the subsequent controller for LED light intensity sampling; The temperature sensor is used to monitor the ambient temperature and transmit the temperature value to the controller; The controller is used to obtain the temperature value of the ambient temperature sensor and the light intensity value output by the photoelectric detector in real time, drive and adjust the LED light source to emit the light intensity required by the system in real time through the fuzzy PID algorithm, and finally output the original random sequence.

2. A quantum entropy source control system according to claim 1, characterized in that: The LED light source is a common LED light source or an LED laser light source.

3. A quantum entropy source control system according to claim 1, characterized in that: The photodetector array is an integrated device of multiple photodetectors of the same type.

4. A quantum entropy source control system according to claim 1, characterized in that: The temperature sensor has an accuracy of ±0.01°C.

5. A quantum entropy source control system according to claim 1, characterized in that: The controller is a field programmable gate array FPGA or a complex programmable logic device CPLD.

6. The control method according to claim 1, characterized in that: The steps include: The quantum entropy source control system is powered on and initialized; The ambient temperature sensor obtains the real-time ambient temperature value and sets the target light intensity value according to the ambient temperature and light intensity change relationship table stored in the controller; The system uses fuzzy PID control algorithm to drive the LED to emit light according to the target light intensity value; The system detects the actual output light intensity of the LED light source through a photodetector array and transmits the actual value of the light intensity to the control system in real time; The control system determines whether the light intensity meets the target setting value. If it meets and is stable, the entropy source outputs the original random sequence. Otherwise, it returns to continue using the fuzzy PID algorithm to adjust the LED output light intensity until the ideal light intensity is reached.

7. A quantum entropy source control system according to claim 6, characterized in that: The method of using fuzzy PID control algorithm in the controller to drive LED to emit light comprises the following steps: The control system uses the error e(t) between the actual LED output light intensity and the target light intensity and the error change rate de / dt as the input of the fuzzy PID controller, the corrected Kp, Ki and Kd as the direct control output of the system, and the LED light source driving voltage u(t) as the indirect control output; According to the error e(t) and the error change rate de / dt, the PID control parameters are adjusted in real time through the fuzzy controller, and then the LED drive voltage u(t) is adjusted in real time until the light intensity is within the target temperature threshold range.

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