Random number generation device based on multi-optical-path mutual injection semiconductor laser system

Abstract

The invention provides a random number generation device based on a multi-optical-path mutual injection semiconductor laser system. The random number generation device is used for solving the problem that in an existing random number generation device based on a semiconductor laser system, a chaotic signal contains a weak period oscillation component due to optical feedback external disturbance. Comprising first and second vertical-cavity surface-emitting lasers; laser output by the first vertical-cavity surface-emitting laser is divided into a first light beam and a second light beam after passing through the first optical fiber coupler, and laser output by the second vertical-cavity surface-emitting laser is divided into a third light beam and a fourth light beam after passing through the fourth optical fiber coupler; the first light beam and the third light beam pass through a second adjustable attenuator and a second polarization controller and then are input into a third optical fiber coupler, and the adjusted first light beam and the adjusted third light beam are injected into a second vertical cavity surface emitting laser and a first vertical cavity surface emitting laser through multiple optical paths of the third optical fiber coupler respectively. According to the multi-optical-path mutual injection structure, time delay characteristics can be effectively suppressed, and weak period oscillation components contained in chaotic signals can be weakened or even eliminated.

Description

Technical Field

[0001] The invention relates to the field of random number generation, in particular to a random number generation device based on a multi-light path mutual injection semiconductor laser system. Background Art

[0002] Random numbers have extensive and important applications in numerical simulation, artificial intelligence, communication security, cryptography and other fields. For example, in communication security, various encryption protocols are usually used to ensure the secure transmission of information, and the implementation of these protocols requires a large number of random numbers. At present, there are usually two ways to obtain random numbers: one is to generate random numbers based on algorithms, and the other is to generate random numbers based on physical random phenomena or processes. Among them, the random numbers generated by the algorithm use the algorithm to give outputs according to the input random number seed, so for a certain input, a fixed algorithm will give a certain output sequence. From this perspective, this type of random number is essentially deterministic and not truly random. Due to the unpredictability of physical random phenomena or processes, the random numbers generated have good randomness and unpredictability, and can generate random numbers of any length according to specific needs. The random numbers generated by this method are particularly suitable for applications with high security requirements, such as cryptography and secure communications. The chaotic laser entropy source based on the output of semiconductor lasers generates random numbers by using the nonlinearity and unpredictability of the physical phenomenon of chaotic dynamics system to generate random numbers. This generation method has high reliability and integration, and provides a lot of convenience for the miniaturization development of random number application systems.

[0003] Although a lot of research has been done on the generation of chaotic entropy sources based on semiconductor lasers, most of them are based on the generation of chaotic lasers by external disturbances such as optical feedback or single optical path injection. Such chaotic lasers usually contain obvious time delay characteristics, that is, the chaotic signal contains weak periodic oscillation components, which seriously affect the quality of the generated random numbers and reduce their randomness. In order to eliminate the time delay characteristics and improve the quality of random number production, some existing studies have adopted methods to increase the complexity of the optical feedback structure, such as adding Bragg gratings, optical amplifiers and other devices, which directly makes the system operation extremely difficult and often leads to instability of the system output, bringing difficulties to the miniaturization and integration of the system; while the existing research system structure is not complicated, but there are obvious restrictions on the feedback time of the external cavity. High-quality chaotic output can only be generated when it meets specific feedback time conditions. This increases the difficulty of system operation to a certain extent and is not conducive to the practical application of the system under complex conditions. In the post-processing part of random number generation, the existing methods will include an effective bit interception module, which will greatly reduce the utilization rate of the sampling bits, reduce the random number generation rate, and increase the complexity of the algorithm. Summary of the invention

[0004] The purpose of the present invention is to provide a random number generator based on a multi-optical mutual injection semiconductor laser system, which is used to solve the technical problem that the chaotic signal caused by the external disturbance of optical feedback in the existing random number generator based on the semiconductor laser system contains weak periodic oscillation components.

[0005] A random number generating device based on a multi-optical path mutual injection semiconductor laser system comprises a first vertical cavity surface emitting laser and a second vertical cavity surface emitting laser;

[0006] The laser light outputted by the first vertical cavity surface emitting laser is divided into a first light beam and a second light beam after passing through a first optical fiber coupler, and the laser light outputted by the second vertical cavity surface emitting laser is divided into a third light beam and a fourth light beam after passing through a fourth optical fiber coupler;

[0007] The first light beam and the third light beam are both input into the third optical fiber coupler after adjusting the feedback strength through the second adjustable attenuator and the polarization direction through the second polarization controller. The adjusted first light beam is injected into the second vertical cavity surface emitting laser through the third optical fiber coupler through multiple optical paths, and the adjusted third light beam is injected into the first vertical cavity surface emitting laser through the third optical fiber coupler through multiple optical paths.

[0008] Optionally, the second light beam is divided into a fifth light beam and a sixth light beam after passing through a second optical fiber coupler;

[0009] The fifth light beam is input into the first polarization beam splitter after the polarization direction of the fifth light beam is adjusted by the fifth polarization controller. The first polarization beam splitter splits the fifth light beam into two independent outputs, which serve as the first entropy source and the second entropy source respectively.

[0010] Optionally, the sixth light beam is fed back to the first vertical cavity surface emitting laser along the original path after being reflected by the first fiber reflector and then adjusted by the first adjustable attenuator to adjust the feedback strength and the first polarization controller to adjust the polarization direction.

[0011] Optionally, the fourth light beam is divided into a seventh light beam and an eighth light beam after passing through a fifth optical fiber coupler;

[0012] The seventh light beam is input into the second polarization beam splitter after the polarization direction of the seventh light beam is adjusted by the fourth polarization controller. The second polarization beam splitter splits the seventh light beam into two independent outputs, which serve as the third entropy source and the fourth entropy source respectively.

[0013] Optionally, the eighth light beam is fed back to the second vertical cavity surface emitting laser along the original path after being reflected by the second optical fiber reflector and after being adjusted by the third adjustable attenuator to adjust the feedback strength and the third polarization controller to adjust the polarization direction.

[0014] Optionally, it also includes a first photoelectric converter, a second photoelectric converter, a third photoelectric converter and a fourth photoelectric converter for converting optical signals of the first entropy source, the second entropy source, the third entropy source and the fourth entropy source into electrical signals respectively.

[0015] Optionally, it further includes a first eight-bit analog-to-digital converter, a second eight-bit analog-to-digital converter, a third eight-bit analog-to-digital converter and a fourth eight-bit analog-to-digital converter;

[0016] The first eight-bit analog-to-digital converter, the second eight-bit analog-to-digital converter, the third eight-bit analog-to-digital converter and the fourth eight-bit analog-to-digital converter respectively quantize the electrical signal samples of the first entropy source, the second entropy source, the third entropy source and the fourth entropy source into a first bit sequence, a second bit sequence, a third bit sequence and a fourth bit sequence.

[0017] Optionally, the first bit sequence, the second bit sequence, the third bit sequence and the fourth bit sequence are interlaced to form an initial random sequence, and the initial random sequence is then subjected to a cyclic XOR operation to generate a physical random number sequence.

[0018] Optionally, the specific steps of generating a physical random number sequence by a cyclic XOR operation of the initial random sequence are:

[0019] S1: Perform bitwise XOR operation on the g-th eight-bit binary code and the n+g-th eight-bit binary code in the initial random sequence, where: g∈(1~n), and g=1 at the initial moment;

[0020] S2: Let g = g + 1 and repeat step S1 until g = n, and concatenate the operation results of step S1 in the order of operation to form a physical random number with a length of n × eight bits;

[0021] S3: Perform an eight-bit bitwise exclusive OR operation on the first n×eight-bit physical random number and the subsequent initial random sequence in units of sample points to generate a subsequent n×eight-bit physical random number;

[0022] S4: Repeat steps S1-S3 to generate a physical random number sequence of infinite length.

[0023] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0024] 1. The optical feedback structure in the present application adopts an external cavity feedback structure, which has a simple design and only requires one optical fiber reflector, and is very easy to generate chaotic oscillations.

[0025] 2. The present application adopts a multi-optical path mutual injection structure, which can broaden the bandwidth of the entropy source by adjusting the frequency detuning of the two lasers, suppress the time delay characteristics caused by the external cavity feedback structure, and improve the quality of the entropy source.

[0026] 3. The post-processing method of the present application includes only two parts: interleaving of sampling points and cyclic XOR operation. The algorithm is simple to implement and does not include a valid bit interception module. It not only improves the utilization rate of the sampling bits, but also enables all sampling bits to be used to generate random numbers, thereby increasing the generation rate of physical random numbers.

[0027] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings of the present invention are as follows.

[0029] Figure 1 Schematic diagram of the structure of the random number generating device of the present invention.

[0030] Figure 2 This is a flow chart of the entropy source signal post-processing of the present invention.

[0031] In the figure: VCSEL1-first vertical cavity surface emitting laser; VCSEL2-second vertical cavity surface emitting laser; FC1-first fiber coupler; FC2-second fiber coupler; FC3-third fiber coupler; FC4-fourth fiber coupler; FC5-fifth fiber coupler; VA1-first adjustable attenuator; VA2-second adjustable attenuator; PC1-first polarization controller; PC2-second polarization controller; PC3-third polarization controller; PC4-fourth polarization controller; FM1-first fiber reflector; FM2-second fiber reflector; PBS1-first polarization beam splitter; PBS2-second polarization beam splitter; PD1-first photoelectric converter; PD2-second photoelectric converter; PD3-third photoelectric converter; PD4-fourth photoelectric converter; ADC1-first eight-bit analog-to-digital converter; ADC2-second eight-bit analog-to-digital converter; ADC3-third eight-bit analog-to-digital converter; ADC4-fourth eight-bit analog-to-digital converter; XOR-exclusive OR operation module. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0033] Example:

[0034] like Figure 1A random number generating device based on a multi-optical path mutual injection semiconductor laser system is shown, comprising a first vertical cavity surface emitting laser VCSEL1 and a second vertical cavity surface emitting laser VCSEL2;

[0035] The laser light outputted by the first vertical cavity surface emitting laser VCSEL1 is divided into a first light beam and a second light beam after passing through a first fiber coupler FC1, and the laser light outputted by the second vertical cavity surface emitting laser VCSEL2 is divided into a third light beam and a fourth light beam after passing through a fourth fiber coupler FC4;

[0036] The first light beam and the third light beam are both input into the third fiber coupler FC3 after adjusting the feedback strength through the second adjustable attenuator VA2 and the polarization direction through the second polarization controller PC2. The adjusted first light beam is injected into the second vertical cavity surface emitting laser VCSEL2 through the third fiber coupler FC3 through multiple optical paths. The adjusted third light beam is injected into the first vertical cavity surface emitting laser VCSEL1 through the third fiber coupler FC3 through multiple optical paths.

[0037] like Figure 1 As shown, the second light beam is divided into a fifth light beam and a sixth light beam after passing through the second fiber coupler FC2, and the fifth light beam is input into the first polarization beam splitter PBS1 after the polarization direction is adjusted by the fifth polarization controller PC5, and the first polarization beam splitter PBS1 divides it into two independent outputs, which are used as the first entropy source and the second entropy source respectively;

[0038] The sixth light beam is fed back to the first vertical cavity surface emitting laser VCSEL1 along the original path after the feedback intensity is adjusted by the first adjustable attenuator VA1 and the polarization direction is adjusted by the first polarization controller PC1 and then reflected by the first fiber reflector FM1.

[0039] like Figure 1 As shown, the fourth light beam is divided into a seventh light beam and an eighth light beam after passing through the fifth fiber coupler FC5, and the seventh light beam is input into the second polarization beam splitter PBS2 after the polarization direction is adjusted by the fourth polarization controller PC4, and the second polarization beam splitter PBS2 divides it into two independent outputs, which are respectively used as the third entropy source and the fourth entropy source;

[0040] The eighth light beam is fed back to the second vertical cavity surface emitting laser VCSEL2 along the original path after the feedback intensity is adjusted by the third adjustable attenuator VA3 and the polarization direction is adjusted by the third polarization controller PC3 and then reflected by the second fiber reflector FM2.

[0041] In this embodiment, the first vertical cavity surface emitting laser VCSEL1 and the second vertical cavity surface emitting laser VCSEL2 are simultaneously lased in the X-PC polarization mode and the Y-PC polarization mode under the disturbance of parallel light feedback and multi-path injection, and chaotic laser output is generated respectively. In this embodiment, the chaotic light mutual injection structure adopts a multi-path mutual injection structure composed of a fiber coupler. The multi-path mutual injection structure is composed of a 2×2 fiber coupler, and the incident light path and the output light path are respectively connected to the two ends of the 2×2 fiber coupler. The incident laser can form multiple incident light paths in the fiber coupler, and then injected into the vertical cavity surface emitting laser, so that the light intensity of each injection light path is relatively weak, the periodic oscillation characteristics of the output chaotic laser are weakened, the complexity is enhanced, and this structure is simple and easy to integrate. By adjusting the frequency detuning of the two lasers, the output of the semiconductor laser can present more complex dynamic characteristics and more stable output, which can broaden the bandwidth of the entropy source, and at the same time can effectively suppress the time delay characteristics in the chaotic light, and improve the quality of the chaotic signal.

[0042] In this embodiment, the optical feedback structure in the present application adopts an external cavity feedback structure, which has a simple design and only requires one optical fiber reflector, and is very easy to generate chaotic oscillations.

[0043] like Figure 2 As shown, the device also includes a first photoelectric converter PD1, a second photoelectric converter PD2, a third photoelectric converter PD3 and a fourth photoelectric converter PD4 for converting optical signals of the first entropy source, the second entropy source, the third entropy source and the fourth entropy source into electrical signals respectively.

[0044] like Figure 2 As shown, the device also includes a first eight-bit analog-to-digital converter ADC1, a second eight-bit analog-to-digital converter ADC2, a third eight-bit analog-to-digital converter ADC3 and a fourth eight-bit analog-to-digital converter ADC4;

[0045] The first eight-bit analog-to-digital converter ADC1, the second eight-bit analog-to-digital converter ADC2, the third eight-bit analog-to-digital converter ADC3 and the fourth eight-bit analog-to-digital converter ADC4 respectively quantize the electrical signal samples of the first entropy source, the second entropy source, the third entropy source and the fourth entropy source into a first bit sequence, a second bit sequence, a third bit sequence and a fourth bit sequence.

[0046] As an embodiment of the present application, the first bit sequence, the second bit sequence, the third bit sequence and the fourth bit sequence are interleaved to form an initial random sequence, and the initial random sequence is then subjected to a cyclic XOR operation module XOR operation to generate a physical random number sequence. The specific steps of generating a physical random number sequence after the initial random sequence is subjected to a cyclic XOR operation module XOR operation are as follows:

[0047] S1: Perform bitwise XOR operation on the g-th eight-bit binary code and the n+g-th eight-bit binary code in the initial random sequence, where: g∈(1~n), and g=1 at the initial moment;

[0048] S2: Let g = g + 1 and repeat step S1 until g = n, and concatenate the operation results of step S1 in the order of operation to form a physical random number with a length of n × eight bits;

[0049] S3: Perform an eight-bit bitwise exclusive OR operation on the first n×eight-bit physical random number and the subsequent initial random sequence in units of sample points to generate a subsequent n×eight-bit physical random number;

[0050] S4: Repeat steps S1-S3 to generate a physical random number sequence of infinite length.

[0051] In this embodiment, n is any non-zero integer, that is, Figure 2 a and b can be equal or unequal Figure 2 Entropy sources 1 to 4 represent the first to fourth entropy sources, respectively, where a, b∈(1 to 4); equality indicates that they come from the same entropy source, and inequality indicates that they come from different entropy sources. The post-processing method of the present application includes only two parts: sampling point interleaving and cyclic XOR operation. The algorithm is simple to implement, and it does not include a valid bit interception module, which not only improves the utilization rate of the sampling bits, but also enables all sampling bits to be used to generate random numbers, thereby improving the generation rate of physical random numbers.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A random number generating device based on a multi-optical path mutual injection semiconductor laser system, characterized in that: comprising a first vertical cavity surface emitting laser and a second vertical cavity surface emitting laser; The laser light outputted by the first vertical cavity surface emitting laser is divided into a first light beam and a second light beam after passing through a first optical fiber coupler, and the laser light outputted by the second vertical cavity surface emitting laser is divided into a third light beam and a fourth light beam after passing through a fourth optical fiber coupler; The first light beam and the third light beam are both input into the third optical fiber coupler after adjusting the feedback strength through the second adjustable attenuator and the polarization direction through the second polarization controller. The adjusted first light beam is injected into the second vertical cavity surface emitting laser through the third optical fiber coupler through multiple optical paths, and the adjusted third light beam is injected into the first vertical cavity surface emitting laser through the third optical fiber coupler through multiple optical paths.

2. A random number generating device based on a multi-optical path mutual injection semiconductor laser system according to claim 1, characterized in that: The second light beam is divided into a fifth light beam and a sixth light beam after passing through a second optical fiber coupler; The fifth light beam is input into the first polarization beam splitter after the polarization direction of the fifth light beam is adjusted by the fifth polarization controller. The first polarization beam splitter splits the fifth light beam into two independent outputs, which serve as the first entropy source and the second entropy source respectively.

3. A random number generating device based on a multi-light path mutual injection semiconductor laser system according to claim 2, characterized in that: The sixth light beam is fed back to the first vertical cavity surface emitting laser along the original path after the feedback intensity is adjusted by the first adjustable attenuator and the polarization direction is adjusted by the first polarization controller and then reflected by the first optical fiber reflector.

4. The random number generating device based on a multi-optical path mutual injection semiconductor laser system according to claim 2, characterized in that: The fourth light beam is divided into a seventh light beam and an eighth light beam after passing through a fifth optical fiber coupler; The seventh light beam is input into the second polarization beam splitter after the polarization direction of the seventh light beam is adjusted by the fourth polarization controller. The second polarization beam splitter splits the seventh light beam into two independent outputs, which serve as the third entropy source and the fourth entropy source respectively.

5. A random number generating device based on a multi-optical path mutual injection semiconductor laser system according to claim 4, characterized in that: The eighth light beam is fed back to the second vertical cavity surface emitting laser along the original path after the feedback intensity is adjusted by the third adjustable attenuator and the polarization direction is adjusted by the third polarization controller and then reflected by the second optical fiber reflector.

6. The random number generating device based on a multi-light path mutual injection semiconductor laser system according to claim 4, characterized in that: It also includes a first photoelectric converter, a second photoelectric converter, a third photoelectric converter and a fourth photoelectric converter for converting the optical signals of the first entropy source, the second entropy source, the third entropy source and the fourth entropy source into electrical signals respectively.

7. The random number generating device based on a multi-optical path mutual injection semiconductor laser system according to claim 4, characterized in that: Also included is a first eight-bit analog-to-digital converter, a second eight-bit analog-to-digital converter, a third eight-bit analog-to-digital converter, and a fourth eight-bit analog-to-digital converter; The first eight-bit analog-to-digital converter, the second eight-bit analog-to-digital converter, the third eight-bit analog-to-digital converter and the fourth eight-bit analog-to-digital converter respectively quantize the electrical signal samples of the first entropy source, the second entropy source, the third entropy source and the fourth entropy source into a first bit sequence, a second bit sequence, a third bit sequence and a fourth bit sequence.

8. The random number generating device based on a multi-light path mutual injection semiconductor laser system according to claim 7, characterized in that: The first bit sequence, the second bit sequence, the third bit sequence and the fourth bit sequence are interlaced and combined to form an initial random sequence, and the initial random sequence is then subjected to a cyclic XOR operation to generate a physical random number sequence.

9. The random number generating device based on a multi-light path mutual injection semiconductor laser system according to claim 8, characterized in that: The specific steps of generating a physical random number sequence through a cyclic XOR operation of the initial random sequence are as follows: S1: Perform bitwise XOR operation on the g-th eight-bit binary code and the n+g-th eight-bit binary code in the initial random sequence, where: g∈(1~n), and g=1 at the initial moment; S2: Let g = g + 1 and repeat step S1 until g = n, and concatenate the operation results of step S1 in the order of operation to form a physical random number with a length of n × eight bits; S3: Perform an eight-bit bitwise exclusive OR operation on the first n×eight-bit physical random number and the subsequent initial random sequence in units of sample points to generate a subsequent n×eight-bit physical random number; S4: Repeat steps S1-S3 to generate a physical random number sequence of infinite length.

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