A quantum random number generator based on feedback adjustment of comparator threshold and a random sequence generation method

Abstract

The application discloses a quantum random number generator based on feedback adjustment of a comparator threshold value and a random sequence generation method. The quantum random number generator comprises a superluminescent diode, a filter, an erbium-doped fiber amplifier, a fiber coupler with a coupling ratio of 50:50, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter and a first photodetector connected with the first beam splitter, a second optical power meter and a second photodetector connected with the second beam splitter, a microcontroller connected with the first optical power meter and the second optical power meter, and a comparator connected with the microcontroller, the first photodetector and the second photodetector. The first photodetector and the second photodetector are connected with the comparator through a differential circuit. The application adjusts the threshold voltage to offset the influence of the output characteristics of a light source on the output random number.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum random number generator, and particularly relates to a quantum random number generator based on feedback adjustment of comparator threshold value and a random sequence generation method. BACKGROUND

[0002] With the continuous development of information technology, information security problems are increasingly prominent, and random numbers play a crucial role in modern science and business, such as cryptography and numerical simulation, so how to generate high-speed and high-performance random numbers becomes a crucial scientific problem. On the one hand, the random numbers generated based on deterministic mathematical algorithms are called pseudo-random numbers, which are predictable in principle. On the other hand, the random numbers generated using the uncertainty principle of quantum mechanics have unpredictable properties, which are called quantum random numbers, and the device for generating quantum random numbers is called quantum random number generator. The rapid development of quantum information technology has accelerated the research of quantum random number generator, and various different implementation schemes have been proposed and experimentally verified. According to the degree of trust in actual involvement, quantum random number generators can be divided into device-independent quantum random number generators, semi-device-independent quantum random number generators and device-reliable quantum random number generators. Device-reliable quantum random number generators assume that the light source, detector and other devices fully comply with the set physical model and are not controlled by eavesdroppers, and by designing appropriate schemes, high-speed usable quantum random numbers can be generated. This type of quantum random number generator technology is relatively mature, and in particular, continuous quantum random number generators that use vacuum state fluctuation noise, laser phase noise and amplified spontaneous emission noise to generate quantum random numbers have gradually moved towards commercialization.

[0003] The general principle of the quantum random number generator scheme based on self-delay difference is shown below. This type of scheme uses a quantum light source with a clear light intensity distribution to generate an optical signal, and an super luminescent diode (SLED) is selected as the quantum light source for example. The amplified spontaneous emission noise optical signal generated by the SLED is bandpass filtered, and then amplified by an erbium-doped fiber amplifier (EDFA). The signal is divided into two beams by a fiber coupler (FC) with a coupling ratio of 50:50. One of the optical signals is connected to an optical delay line (TODL), and then two identical photodetectors (PDs) are used to detect the intensity of the optical signal and convert it into an electrical signal. The difference between the two electrical signals is obtained by difference, and the voltage of the difference signal is v. Finally, the difference signal is coupled to a comparator (CMP) to compare with the threshold voltage v e of the comparator, and the original random sequence is output. The threshold voltage v eThe setting of the threshold voltage is related to the differential signal voltage v, that is, the probability of ensuring that the differential signal voltage is less than or greater than the threshold voltage is 50%. If the working state of the quantum random number generator is stable, the setting of the initial threshold voltage can ensure that the differential signal is equally divided, and a random sequence with the same probability of 0 and 1 is obtained, so that the randomness of the output random number is ensured. However, in practice, the quantum light source of the quantum random number generator is inevitably affected by environmental factors such as temperature, humidity, electromagnetic radiation, etc., so that the output characteristics of the quantum light source change, the coupling ratio of the FC is affected, and the threshold voltage of the comparator set initially cannot equally divide the differential signal, thereby reducing the randomness of the output random number and affecting the security of the actual quantum random number generator. SUMMARY

[0004] The present application aims at the problem that the output characteristics of the quantum light source change, the coupling ratio of the fiber coupler is affected, and the threshold voltage of the comparator set initially is invalid in the existing quantum random number generator based on delay self-difference, and the bias exists in the output random number, and proposes a quantum random number generator based on feedback adjustment of the threshold voltage of the comparator and a random sequence generation method, which offsets the influence of the change of the output characteristics of the light source on the output random number by adjusting the threshold voltage.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] The present application proposes a quantum random number generator based on feedback adjustment of the threshold voltage of the comparator, which comprises a superluminescent diode, a filter, an erbium-doped fiber amplifier, a fiber coupler with a coupling ratio of 50:50, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter and a first photodetector connected to the first beam splitter, a second optical power meter and a second photodetector connected to the second beam splitter, a microcontroller connected to the first optical power meter and the second optical power meter, and a comparator connected to the microcontroller, the first photodetector and the second photodetector; the first photodetector and the second photodetector are connected to the comparator through a differential circuit.

[0007] Further, the fiber coupler is connected to the optical delay line and the first beam splitter.

[0008] Further, the splitting ratio of the first beam splitter and the second beam splitter is 1:9.

[0009] Further, the first beam splitter, the first optical power meter and the microcontroller constitute a first circuit, the first beam splitter, the first photodetector and the differential circuit constitute a second circuit, the second beam splitter, the second photodetector and the differential circuit constitute a third circuit, and the second beam splitter, the second optical power meter and the microcontroller constitute a fourth circuit.

[0010] The application further provides a random sequence generation method of a quantum random number generator based on feedback adjustment of a comparator threshold value, comprising:

[0011] The super radiation light emitting diode emits a light signal, which is filtered by a filter to obtain a light signal with a wavelength of λ;

[0012] The filtered light signal is amplified by an erbium-doped fiber amplifier, and then is divided into two beams by a fiber coupler with a coupling ratio of 50:50, wherein one beam is connected to an optical delay line; when the delay time is r, the optical power of the delay line is P(t i +r), and the optical power of the other line is P(t i );

[0013] Then the two light signals pass through a first beam splitter and a second beam splitter with the same splitting ratio, and are divided into two paths again, wherein the two light signals corresponding to the delay line are a first line light signal and a second line light signal, and the light signal not passing through the delay line is divided into two paths by the second beam splitter, which are a third line light signal and a fourth line light signal;

[0014] The first line light signal is measured by a first optical power meter, the second line light signal is intensity detected by a first photodetector, the third line light signal is intensity detected by a second photodetector, and the fourth line light signal is measured by a second optical power meter; the optical powers P1, P2, P3 and P4 of the light signals of the respective lines are obtained;

[0015] The first photodetector and the second photodetector convert the second line light signal and the third line light signal into a second line electrical signal and a third line electrical signal, respectively, and based on P2, P3 and the response coefficients A of the first photodetector and the second photodetector, the output voltages v2 and v3 of the second line and the third line are calculated; the second line electrical signal and the third line electrical signal are differentiated by a differential circuit to obtain a differential signal with a voltage of v=v2-v3, which is transmitted to a comparator;

[0016] P1 and P4 are transmitted to a microcontroller for comparison and calculation, and the optical power values of the first line and the fourth line in T=n*t i time are accumulated, and the average value of the optical power difference between the first line light signal and the fourth line light signal is calculated wherein represents the average optical power of the first line light signal in T time, represents the average optical power of the fourth line light signal in T time; based on the corresponding threshold voltage v e is calculated The microcontroller adjusts the threshold voltage v e of the comparator based on the obtained threshold voltage.

[0017] Comparator pairs v and v e Compare, if v <v e If v > v, then output bit 0. e If the output bit is 1, then a random sequence is obtained.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention achieves real-time monitoring of optical signal intensity by adding two beam splitters. Using a feedback control method, the effective threshold voltage of the comparator is calculated based on the change in optical signal intensity, thereby adjusting the threshold voltage of the comparator. This achieves equal probability division of the differential signal and can output an unbiased random sequence. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a quantum random number generator based on feedback adjustment of the comparator threshold, according to an embodiment of the present invention. Detailed Implementation

[0021] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments:

[0022] like Figure 1 As shown, a quantum random number generator based on feedback-adjusted comparator threshold includes: a superluminescent diode (SLED), a filter, an erbium-doped fiber amplifier (EDFA), a fiber coupler (FC) with a coupling ratio of 50:50, an optical delay line (TODL), a first beam splitter (BS) and a second beam splitter with a splitting ratio of 1:9, a first optical power meter (PM) and a first photodetector (PD) connected to the first beam splitter, a second optical power meter and a second photodetector connected to the second beam splitter, and a microcontroller (MCU) connected to the first optical power meter and the second optical power meter, and a comparator (CMP) connected to the microcontroller, the first photodetector, and the second photodetector; the first photodetector and the second photodetector are connected to the comparator via a differential circuit.

[0023] Furthermore, the fiber coupler is connected to the first beam splitter via an optical delay line.

[0024] Furthermore, the first beam splitter, the first optical power meter, and the microcontroller constitute a first circuit; the first beam splitter, the first photodetector, and the differential circuit constitute a second circuit; the second beam splitter, the second photodetector, and the differential circuit constitute a third circuit; and the second beam splitter, the second optical power meter, and the microcontroller constitute a fourth circuit.

[0025] Based on the above embodiments, another aspect of the present invention proposes a method for generating random sequences using a quantum random number generator based on feedback adjustment of the comparator threshold, comprising:

[0026] The superluminescent diode emits a light signal, which is then filtered by a filter to obtain a light signal with a wavelength of λ.

[0027] The filtered optical signal is amplified by an erbium-doped fiber amplifier, and then split into two beams by a 50:50 fiber coupler, one of which is connected to an optical delay line; when the delay time is r, the optical power of the delay line is P(t). i +r), the optical power of the other line is P(t) i );

[0028] The two optical signals are then split into two paths again by a first beam splitter and a second beam splitter with a splitting ratio of 1:9, respectively. The two optical signals corresponding to the delay lines are the first ( Figure 1 1) Line optical signal and 2) Figure 1 The optical signal from line 2, which has not passed through the delay line, is split into two paths by the second beam splitter, namely the third ( Figure 1 3) Line optical signal and fourth ( Figure 1 4) Line optical signal;

[0029] The optical power of the first line optical signal is measured using a first optical power meter. The intensity of the second line optical signal is detected using a first photodetector. The intensity of the third line optical signal is detected using a second photodetector. The optical power of the fourth line optical signal is measured using a second optical power meter. The optical power (intensity) P1, P2, P3, and P4 of each line optical signal are obtained respectively. Specifically, when the center wavelength of the light output from the light source and the coupling ratio of the fiber coupler remain stable, the optical power of the first line optical signal is P1 = 0.1 * P(t) i +r), the optical power of the second line optical signal is P2 = 0.9 * P(t) i +r), the optical power of the third line optical signal is P3 = 0.1 * P(t) i The optical power of the fourth line optical signal is P4 = 0.9 * P(t). i ).

[0030] The first photoelectric detector and the second photoelectric detector respectively convert the second line optical signal and the third line optical signal into the second line electrical signal and the third line electrical signal, the output voltage value is proportional to the optical power (optical intensity) of the optical signal, the response coefficient of PD is A, the output voltages v2 and v3 of the second line and the third line are calculated based on P2, P3 and the response coefficient A of the first photoelectric detector and the second photoelectric detector; the second line electrical signal and the third line electrical signal are differentiated through a differential circuit to obtain a differential signal with a voltage value v=v2-v3, which is transmitted to a comparator; specifically, v2=0.9*P(t i +r)*A, and v3=0.9*P(t i +r)*A.

[0031] The optical power P1 measured by the first line and the optical power P4 measured by the fourth line are transmitted to the microcontroller for comparison and calculation, and the optical power values of the first line and the fourth line in T=n*t i time are accumulated, and the average value of the optical power difference between the first line optical signal and the fourth line optical signal is calculated Wherein represents the average optical power of the first line optical signal in T time, represents the average optical power of the fourth line optical signal in T time; based on the corresponding threshold voltage v is calculated. The microcontroller adjusts the threshold voltage v e of the comparator based on the obtained threshold voltage v

[0032] The comparator compares the sampling voltage v with v e , if v e , then a bit 0 is output, and if v>v e , then a bit 1 is output, so that a random sequence is obtained.

[0033] The present application ensures the effectiveness of the threshold voltage of the comparator by monitoring the optical power in real time and dynamically adjusting the threshold voltage of the comparator, can divide the sampled differential signal with equal probability, and ensures the stability of the quantum random number generator system.

[0034] The above only shows the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A quantum random number generator based on feedback adjustment of a comparator threshold, characterized by, The application relates to a super-radiation light-emitting diode, a filter, an erbium-doped optical fiber amplifier, a 50:50 fiber coupler, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter connected with the first beam splitter, a first photodetector, a second optical power meter connected with the second beam splitter, a second photodetector, a microcontroller connected with the first optical power meter and the second optical power meter, and a comparator connected with the microcontroller, the first photodetector and the second photodetector; the first photodetector and the second photodetector are connected with the comparator through a differential circuit; and the fiber coupler is connected with the first beam splitter through the optical delay line. The splitting ratios of the first beam splitter and the second beam splitter are 1:

9.

2. The quantum random number generator based on feedback adjustment of comparator threshold value according to claim 1, characterized in that, The first beam splitter, the first optical power meter and the microcontroller form a first circuit, the first beam splitter, the first photodetector and the differential circuit form a second circuit, the second beam splitter, the second photodetector and the differential circuit form a third circuit, and the second beam splitter, the second optical power meter and the microcontroller form a fourth circuit.

3. The quantum random number generator based on feedback adjustment of comparator threshold value according to claim 1, characterized in that, The application relates to a super-radiation light-emitting diode, a filter, an erbium-doped optical fiber amplifier, a 50:50 fiber coupler, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter connected with the first beam splitter, a first photodetector, a second optical power meter connected with the second beam splitter, a second photodetector, a microcontroller connected with the first optical power meter and the second optical power meter, and a comparator connected with the microcontroller, the first photodetector and the second photodetector; the first photodetector and the second photodetector are connected with the comparator through a differential circuit; and the fiber coupler is connected with the first beam splitter through the optical delay line.

4. A method for generating a random sequence based on a quantum random number generator with feedback-regulated comparator threshold according to any one of claims 1 to 3, characterized in that The splitting ratios of the first beam splitter and the second beam splitter are 1:

9. The first beam splitter, the first optical power meter and the microcontroller form a first circuit, the first beam splitter, the first photodetector and the differential circuit form a second circuit, the second beam splitter, the second photodetector and the differential circuit form a third circuit, and the second beam splitter, the second optical power meter and the microcontroller form a fourth circuit. The filtered optical signal is amplified by an erbium-doped fiber amplifier, and then is divided into two beams by a fiber coupler with a coupling ratio of 50:50, one of which is connected to an optical delay line; when the delay time is r, the optical power of the delay line is , and the optical power of the other line is ; The application relates to a super-radiation light-emitting diode, a filter, an erbium-doped optical fiber amplifier, a 50:50 fiber coupler, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter connected with the first beam splitter, a first photodetector, a second optical power meter connected with the second beam splitter, a second photodetector, a microcontroller connected with the first optical power meter and the second optical power meter, and a comparator connected with the microcontroller, the first photodetector and the second photodetector; the first photodetector and the second photodetector are connected with the comparator through a differential circuit; and the fiber coupler is connected with the first beam splitter through the optical delay line. The splitting ratios of the first beam splitter and the second beam splitter are 1:

9. The first beam splitter, the first optical power meter and the microcontroller form a first circuit, the first beam splitter, the first photodetector and the differential circuit form a second circuit, the second beam splitter, the second photodetector and the differential circuit form a third circuit, and the second beam splitter, the second optical power meter and the microcontroller form a fourth circuit. The application relates to a super-radiation light-emitting diode, a filter, an erbium-doped optical fiber amplifier, a 50:50 fiber coupler, an optical delay line, a first beam splitter and a second beam splitter with the same splitting ratio, a first optical power meter connected with the first beam splitter, a first photodetector, a second optical power meter connected with the second beam splitter, a second photodetector, a microcontroller connected with the first optical power meter and the second optical power meter, and a comparator connected with the microcontroller, the first photodetector and the second photodetector; the first photodetector and the second photodetector are connected with the comparator through a differential circuit; and the fiber coupler is connected with the first beam splitter through the optical delay line. The splitting ratios of the first beam splitter and the second beam splitter are 1:

9. The first beam splitter, the first optical power meter and the microcontroller form a first circuit, the first beam splitter, the first photodetector and the differential circuit form a second circuit, the second beam splitter, the second photodetector and the differential circuit form a third circuit, and the second beam splitter, the second optical power meter and the microcontroller form a fourth circuit. obtaining optical power of each line optical signal , , , ; The first photoelectric detector and the second photoelectric detector respectively convert the second line optical signal and the third line optical signal into a second line electrical signal and a third line electrical signal, and calculate the output voltages of the second line and the third line based on , and the response coefficients A of the first photoelectric detector and the second photoelectric detector respectively , ; the second line electrical signal and the third line electrical signal are differentiated through a differential circuit to obtain a differential signal with a voltage of v= - , which is transmitted to a comparator; Will and transmitted to the microcontroller for comparison calculation, cumulative T = n* The optical power values of the first line and the fourth line in the T time are calculated to obtain the average value of the optical power difference between the first line optical signal and the fourth line optical signal - , wherein represents the average optical power of the first line optical signal in T time, represents the average optical power of the fourth line optical signal in T time; based on The corresponding threshold voltage is calculated = *A, the microcontroller adjusts the threshold voltage of the comparator based on the threshold voltage obtained ;​ The comparator compares v with and outputs a bit 0 if v and a bit 1 if v , thus obtaining a random sequence.

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