Chaotic module link delay test system and method

Abstract

This invention relates to information technology. The purpose of this invention is to solve the problem of inaccurate measurement of time delay mismatch in current chaotic modular link systems. It provides a chaotic modular link delay testing system and method, the technical solution of which can be summarized as follows: A continuous laser is used as a test carrier, and this test carrier is split into two beams, one outputting to the chaotic modular link system under test; the other test carrier is mixed with the output of the chaotic decryption device of the chaotic modular link system under test at a 90° angle to achieve coherent detection with zero difference, obtaining a mixed optical field; the mixed optical field is then converted by photoelectric conversion to output a Q-component signal; the input Q-component signal is sampled at high speed, and a phase mismatch term is calculated; an autocorrelation operation is performed on the phase mismatch term to obtain a correlation curve; and the time delay corresponding to the second peak is calculated based on the correlation curve to obtain the measured time delay mismatch Δt. The beneficial effect of this invention is that it can quickly and accurately calculate the measured time delay mismatch Δt, and it is applicable to chaotic modular link systems.

Description

Technical Field

[0001] This application relates to information technology, and in particular to a system and method for testing the link delay of chaotic modules. Background Technology

[0002] In a chaotic module link system, a typical system includes a service carrier input, an encryption link, a decryption link, and a chaotic decryption device. The service carrier input is connected to the output of the encryption link and the input of the decryption link, respectively. The outputs of the encryption link and the decryption link are connected to the input of the chaotic decryption device. During operation, the time delay of the chaotic phase scrambling and descrambling operations applied to the service carrier needs to be strictly controlled. This ensures that when the chaotically scrambled service carrier reaches the chaotic decryption device, the synchronously descrambled signal also reaches the device precisely. The transmission delays of both need to be precisely aligned, with a delay error of less than ~10 ps. When a new chaotic module system is built, to achieve accurate time delay matching for the chaotic phase scrambling and descrambling operations applied to the service carrier, the time delay mismatch Δt needs to be precisely measured. In existing technologies, the time delay mismatch Δt is calculated by individually measuring the delay of each optical or electrical device, accumulating the results in the corresponding optical path, and then comparing the accumulated delays of the two optical paths to finally estimate a time delay mismatch Δt. However, since the delays of the photoelectric conversion devices involved cannot be accurately measured, and the delay errors of each device accumulate, the existing methods for estimating the time delay mismatch Δt are both time-consuming and have low measurement accuracy (approximately on the order of 1 to 10 ns).

[0003] Therefore, existing technologies cannot accurately and quickly measure the time delay mismatch Δt in chaotic module link systems. Summary of the Invention

[0004] The purpose of this application is to solve the problem that the delay mismatch in chaotic module link systems cannot be accurately measured, and to provide a chaotic module link delay testing system and method.

[0005] The technical solution adopted by this application to solve the above-mentioned technical problems provides a chaotic module link delay test system, including a laser beam splitter module, a balanced coherent receiver module, and a sampling analysis module. The first output terminal of the laser beam splitter module is used to connect to the service carrier input terminal of the chaotic module link system under test. The second output terminal of the laser beam splitter module is connected to the second input terminal of the balanced coherent receiver module. The first input terminal of the balanced coherent receiver module is connected to the output terminal of the chaotic decryption device of the chaotic module link system under test. The Q component output terminal of the balanced coherent receiver module is connected to the input terminal of the sampling analysis module.

[0006] The laser beam splitting module has an input terminal for inputting a continuous laser as a test carrier, and splits the test carrier into beams and outputs them through a first output terminal and a second output terminal respectively.

[0007] The balanced coherent receiving module is used to perform 90° mixing between the output of the chaotic decryption device of the test carrier and the chaotic module link system under test to achieve self-zero difference coherent detection, obtain the mixed optical field, and output the Q component signal after photoelectric conversion of the mixed optical field.

[0008] The sampling and analysis module is used to sample the input Q component signal at high speed, calculate the phase mismatch term, perform autocorrelation operation on the phase mismatch term to obtain the correlation curve, and then calculate the time delay corresponding to the second peak based on the correlation curve to obtain the measured time delay mismatch Δt. The phase mismatch term refers to the phase term generated by the light field output by the chaotic decryption device due to the time delay mismatch between the encryption link and the decryption link.

[0009] Specifically, the sampling and analysis module includes a high-speed oscilloscope unit and a digital processing unit. The input terminal of the high-speed oscilloscope unit is connected to the Q component output terminal of the balanced coherent receiving module, and the output terminal of the high-speed oscilloscope unit is connected to the digital processing unit.

[0010] The high-speed oscilloscope unit is used to perform high-speed sampling of the Q component signal output from the Q component output terminal of the balanced coherent receiver module to obtain the Q component digital signal.

[0011] The digital processing unit is used to calculate the phase mismatch term based on the Q component digital signal acquired by high-speed sampling, perform autocorrelation operation on the phase mismatch term to obtain the correlation curve, and then calculate the time delay corresponding to the second peak based on the correlation curve to obtain the measured time delay mismatch Δt.

[0012] Furthermore, the Q component output of the balanced coherent receiver module includes Q... p Output terminal and Q n At the output terminal, the Q p The output terminal is used to output Q. p The electrical signal corresponding to the light field is denoted as Q. p (t); the Q n The output terminal is used to output Q. n The electrical signal corresponding to the light field is denoted as Q. n (t).

[0013] Specifically, the first input terminal of the balanced coherent receiving module is a signal optical port, and the second input terminal of the balanced coherent receiving module is a local oscillator optical port.

[0014] Furthermore, when the first input terminal of the balanced coherent receiving module is a signal optical port and the second input terminal of the balanced coherent receiving module is a local oscillator optical port, the step of calculating the phase mismatch term based on the Q component digital signal acquired by high-speed sampling includes:

[0015]

[0016] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the chaotic module link system under test is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0017] Q(t) = Q p (t)-Q n (t).

[0018] Specifically, the first input terminal of the balanced coherent receiving module is the local oscillator optical port, and the second input terminal of the balanced coherent receiving module is the signal optical port.

[0019] Furthermore, when the first input terminal of the balanced coherent receiving module is a local oscillator optical port and the second input terminal of the balanced coherent receiving module is a signal optical port, the step of calculating the phase mismatch term based on the Q component digital signal acquired by high-speed sampling includes:

[0020]

[0021] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0022] Q(t) = Q p (t)-Q n (t).

[0023] The technical solution adopted by this application to solve the above-mentioned technical problems includes, in its second aspect, a method for testing the link delay of a chaotic module, comprising the following steps:

[0024] Select a continuous laser as the test carrier, and split the test carrier into beams, outputting one beam to the link system of the chaotic module under test;

[0025] Another test carrier is mixed with the output of the chaotic decryption device of the chaotic module link system under test by 90° to achieve self-zero difference coherent detection, and the mixed optical field is obtained. The mixed optical field is then converted by photoelectric conversion to output the Q component signal.

[0026] The input Q component signal is sampled at high speed, and the phase mismatch term is calculated. The phase mismatch term is then autocorrelated to obtain the correlation curve. The time delay corresponding to the second peak is calculated based on the correlation curve to obtain the measured time delay mismatch Δt. The phase mismatch term refers to the phase term generated by the light field output by the chaotic decryption device due to the time delay mismatch between the encryption link and the decryption link.

[0027] Specifically, the 90° mixing includes:

[0028] The output of the chaotic decryption device of the chaotic module link system under test is phase-shifted by kπ+π / 2 and then coherently mixed with the test carrier, where k is an integer.

[0029] Furthermore, when k is even, the calculation method for the phase mismatch term includes:

[0030]

[0031] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0032] Q(t) = Q p (t)-Q n (t)

[0033] Here, Q p (t) refers to the Q component signal in the Q component signal. p The electrical signal Q corresponding to the light field n (t) represents the Q component signal in the Q component signal. n The electrical signal corresponding to the light field.

[0034] Specifically, when k is odd, the calculation method for the phase mismatch term includes:

[0035]

[0036] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam.PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0037] Q(t) = Q p (t)-Q n (t)

[0038] Here, Q p (t) refers to the Q component signal in the Q component signal. p The electrical signal Q corresponding to the light field n (t) represents the Q component signal in the Q component signal. n The electrical signal corresponding to the light field.

[0039] The beneficial effect of this application is that, in the scheme of this application, a known continuous laser is input into the chaotic module link system under test as a test carrier, and the test carrier is mixed with the output of the chaotic decryption device of the chaotic module link system under test at 90° to achieve coherent detection with zero difference, so as to obtain a mixed optical field. The mixed optical field is converted by photoelectric conversion and output as a Q component signal. The input Q component signal is sampled at high speed and the phase mismatch term is calculated. The phase mismatch term is then autocorrelated to obtain a correlation curve. The time delay corresponding to the second peak is calculated based on the correlation curve to obtain the measured time delay mismatch Δt. It can be seen that the whole scheme is simple and easy to implement, and the calculated measured time delay mismatch Δt is relatively accurate, reaching the ~10ps level, which provides the corresponding time delay mismatch Δt data for subsequent adjustment of the time delay mismatch Δt of the chaotic module link system under test. Attached Figure Description

[0040] Figure 1 This is a schematic system block diagram of the chaotic module link delay test system provided in the first aspect of the embodiments of this application after being connected with the chaotic module link system under test. Detailed Implementation

[0041] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. In the following description, specific details such as particular system structures and technologies are set forth for illustrative purposes rather than for limiting the scope of the application, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art should understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted to avoid unnecessary detail from obscuring the description of this application.

[0042] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0043] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0044] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0045] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0047] Figure 1The diagram illustrates a schematic system block diagram of a chaotic module link delay test system provided in the first aspect of this application after being connected to a chaotic module link system under test. This is an example and not a limitation. The chaotic module link delay test system includes a laser beam splitter module, a balanced coherent receiver module, and a sampling analysis module. The first output terminal of the laser beam splitter module is connected to the service carrier input terminal of the chaotic module link system under test. The second output terminal of the laser beam splitter module is connected to the second input terminal of the balanced coherent receiver module. The first input terminal of the balanced coherent receiver module is connected to the output terminal of the chaotic decryption device of the chaotic module link system under test. The Q component output terminal of the balanced coherent receiver module is connected to the input terminal of the sampling analysis module.

[0048] Here, the laser beam splitting module has an input terminal for inputting a continuous laser as a test carrier, and splits the test carrier into beams and outputs them through the first output terminal and the second output terminal respectively.

[0049] The balanced coherent receiver module is used to perform 90° mixing between the test carrier and the output of the chaotic decryption device of the link system of the chaotic module under test to achieve coherent detection with zero difference, obtain the mixed optical field, and output the Q component signal after photoelectric conversion of the mixed optical field.

[0050] The sampling and analysis module is used to sample the input Q component signal at high speed, calculate the phase mismatch term, perform autocorrelation on the phase mismatch term to obtain the correlation curve, and then calculate the time delay corresponding to the second peak based on the correlation curve to obtain the measured time delay mismatch Δt. The phase mismatch term refers to the phase term generated by the light field output by the chaotic decryption device due to the time delay mismatch between the encryption link and the decryption link.

[0051] Understandably, in this chaotic module link delay test system, a known continuous laser is used as the test carrier. The laser beam splitter is used to split the laser beam, and one beam is input to the chaotic module link system under test. After chaotic scrambling and descrambling through the encryption and decryption links, the output is sent to the chaotic decryption device. The output of the test carrier and the chaotic decryption device of the chaotic module link system under test are then mixed at 90° through a balanced coherent receiving module to achieve coherent detection with zero difference, resulting in a mixed optical field. The mixed optical field is then converted by photoelectric conversion to output a Q component signal. Finally, the sampling and analysis module performs high-speed sampling on the Q component signal and calculates the phase mismatch term. The phase mismatch term is then autocorrelated to obtain a correlation curve. The time delay corresponding to the second peak is calculated based on the correlation curve to obtain the measured time delay mismatch Δt.

[0052] The secondary peak here refers to the minimum value other than the primary peak.

[0053] See Figure 1To provide a sampling analysis module, in some embodiments, the sampling analysis module may include a high-speed oscilloscope unit and a digital processing unit, wherein the input terminal of the high-speed oscilloscope unit is connected to the Q component output terminal of the balanced coherent receiver module, and the output terminal of the high-speed oscilloscope unit is connected to the digital processing unit.

[0054] Here, the high-speed oscilloscope unit is used to sample the Q component signal output from the Q component output terminal of the balanced coherent receiver module at high speed to obtain the Q component digital signal;

[0055] The digital processing unit is used to calculate the phase mismatch term based on the Q component digital signal acquired by the high-speed sampling, perform autocorrelation operation on the phase mismatch term to obtain the correlation curve, and then calculate the time delay corresponding to the second peak based on the correlation curve to obtain the measured time delay mismatch Δt.

[0056] It is understandable that in the above embodiments, in order to meet the needs of subsequent analysis and calculation, a digital processing unit should be used first, and a high-speed oscilloscope unit should be used for high-speed sampling to reduce errors and make the subsequent analysis and calculation results more accurate.

[0057] Since the Q component signal output by a balanced coherent receiver module generally includes Q... p The electrical signal and Q corresponding to the light field n The electrical signal corresponding to the light field; therefore, in some embodiments, the Q component output of the balanced coherent receiver module may include Q... p Output terminal and Q n Output terminal, where Q p The output terminal is used to output Q. p The electrical signal corresponding to the light field is denoted as Q. p (t); Q n The output terminal is used to output Q. n The electrical signal corresponding to the light field is denoted as Q. n (t).

[0058] It is understandable that Q in the above embodiments p Output terminal and Q n The output terminal is the corresponding output terminal in the existing balanced coherent receiver, which is a relatively mature technology in the existing technology, and will not be described in detail here.

[0059] Since the input terminals of a balanced coherent receiver module generally include a signal optical port and a local oscillator optical port, in some embodiments, the first input terminal of the balanced coherent receiver module may be the signal optical port, and the second input terminal of the balanced coherent receiver module may be the local oscillator optical port.

[0060] It is understood that in the above embodiments, the output of the chaotic decryption device of the chaotic module link system under test is input to the balanced coherent receiving module through the signal optical port, while the test carrier is input to the balanced coherent receiving module through the local oscillator optical port.

[0061] When the first input terminal of the balanced coherent receiver module is a signal optical port, and the second input terminal of the balanced coherent receiver module is a local oscillator optical port, in some embodiments, the phase mismatch term calculated based on the Q component digital signal acquired by high-speed sampling may include:

[0062]

[0063] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0064] Q(t) = Q p (t)-Q n (t).

[0065] As can be seen from the formula above, it is only necessary to obtain Q. p (t) and Q n (t), and then combined with the known data, the corresponding phase mismatch term Δφ(t) can be calculated. Then, autocorrelation operation is performed on it to find the time delay corresponding to the second peak (minimum) of the corresponding curve, which is the time delay mismatch Δt.

[0066] In some embodiments, the first input terminal of the balanced coherent receiver module can be set as the local oscillator optical port, while the second input terminal of the balanced coherent receiver module can be set as the signal optical port.

[0067] It is understood that in the above embodiments, the output of the chaotic decryption device of the chaotic module link system under test is input to the balanced coherent receiving module through the local oscillator optical port, while the test carrier is input to the balanced coherent receiving module through the signal optical port.

[0068] When the first input terminal of the balanced coherent receiver module is a local oscillator optical port, and the second input terminal of the balanced coherent receiver module is a signal optical port, in some embodiments, the phase mismatch term calculated based on the Q component digital signal acquired by high-speed sampling may include:

[0069]

[0070] Where Δφ(t) refers to the phase mismatch term, Rd A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0071] Q(t) = Q p (t)-Q n (t).

[0072] As can be seen from the formula above, it is only necessary to obtain Q. p (t) and Q n (t), and then combined with the known data, the corresponding phase mismatch term Δφ(t) can be calculated. Then, autocorrelation operation is performed on it to find the time delay corresponding to the second peak (minimum) of the corresponding curve, which is the time delay mismatch Δt.

[0073] The principle of this application is as follows:

[0074] Assume the optical field emitted by a continuous-wave laser (CW) can be expressed by the following equation:

[0075] E CW (t)=A CW ·exp[i·(ω0t+φ0+φ N (t))]

[0076] Among them, A CW The amplitude of the optical field of the continuous laser is represented by ω, which is a constant value. ω0 represents the angular frequency of the continuous laser, φ0 represents the initial phase of the continuous laser, and φ N (t) represents the phase noise of the continuous laser, and i represents the imaginary unit.

[0077] After the light field is subjected to chaotic perturbations by the encryption and decryption links, the output from the chaotic decryption device can be expressed as:

[0078]

[0079] Among them, C A (t) and C B (t) represent the electrical signals after the chaotic encryption light field (the light field input to the chaotic decryption device after the encryption link) and the chaotic decryption light field (the light field input to the chaotic decryption device after the decryption link) are detected by their respective photodetectors, V π A is the half-wave voltage of the phase modulator used in the chaotic module link system. PM This represents the amplitude of the light field output from the output terminal of the chaotic decryption device in the tested chaotic module link system.

[0080] High-speed photodetectors typically have DC blocking characteristics, therefore C A (t) and C B If (t) is an AC signal fluctuating around 0, then the modulation depth is defined as follows:

[0081]

[0082] Where C(t) represents the above C A (t) or C B (t), V pp Indicates the corresponding signal (C) A (t) or C B The peak-to-peak value of (t) is given by max{} and min{}, which represent the maximum and minimum values ​​of the time-domain variable, respectively.

[0083] The AC signal approximately satisfies:

[0084] max{C(t)}≈-min{C(t)}

[0085] The peak-to-peak value V of C(t) can be controlled by controlling the light power incident on the photodetector. pp , so that η PM ≤1.

[0086] So:

[0087]

[0088] For E PM (t) After implementing a kπ+π / 2 phase shift and then self-coherent mixing, the electrical signal after photoelectric conversion can be expressed as:

[0089]

[0090] Among them, R d The efficiency of photoelectric conversion (i.e., the responsivity of photoelectric conversion in the photodetector of the balanced receiver module) is represented by k, which can take any integer, including negative integers, 0, and positive integers.

[0091] From the above formula, we can obtain:

[0092]

[0093] Where U(t) represents an intermediate quantity for convenient subsequent calculations, and R d A CW 2 and R d A PM 2 Corresponding to E respectively CW (t) and E PM (t) The electrical signal being detected can be measured separately.

[0094] When k is even (including negative even numbers), according to the above formula... From the periodicity of the cosine function, we can obtain:

[0095]

[0096] Therefore:

[0097]

[0098] When k is odd (including negative odd numbers), the same applies according to the above formula. From the periodicity of the cosine function, we can obtain:

[0099]

[0100] Therefore:

[0101]

[0102] And because of C A (t-Δt) and C B Δφ(t) is a chaotic synchronization signal with a very high correlation coefficient (typically exceeding 92%). Therefore, performing autocorrelation on Δφ(t) yields the time delay corresponding to the second peak of the correlation curve, which is the time delay mismatch Δt. Simultaneously, because C... A (t-Δt) and C B (t) is a subtraction relationship, therefore this peak should have the characteristic of being concave downwards (minimum value).

[0103] In reality, a coherent receiver can be conveniently used to achieve a phase shift of ±π / 2. Typically, coherent receivers employ balanced detection, i.e., balanced coherent receivers, which can further improve the signal-to-noise ratio.

[0104] Suppose a balanced coherent receiver has an optical field transfer function S as follows:

[0105]

[0106] E PM (t) and E CW (t) When the signal optical port (S port) and local oscillator optical port (LO port) of the balanced coherent receiver are mixed, four optical fields are obtained, as shown below:

[0107]

[0108] In the above formula, the four optical fields are detected by a photodetector, and the corresponding electrical signals are obtained as follows:

[0109]

[0110] Rd This indicates the responsivity of the photodetector in the balanced receiving module.

[0111] Substituting E into the above formula CW (t)=A CW ·exp[i·(ω0t+φ0+φ N (t))] and

[0112] We can obtain:

[0113]

[0114] After differentially dividing the I-channel signal and the Q-channel signal respectively, we get:

[0115]

[0116] This corresponds to the case where k is odd, i.e., the phase term in the above equation satisfies the following expression.

[0117] have to:

[0118]

[0119] therefore:

[0120]

[0121] Then perform autocorrelation on Δφ(t) to find the time delay corresponding to the second peak of the correlation curve, which is the time delay mismatch Δt.

[0122] Simultaneously, the input optical fields of the local oscillator port and the signal optical port can be exchanged, that is, E PM (t) and E CW (t) The signals are mixed by inputting them into the local oscillator (LO) port and the signal (S) port of the balanced coherent receiver, respectively. This results in four optical fields, as shown below:

[0123]

[0124] In the above formula, the four optical fields are detected by a photodetector, and the corresponding electrical signals are obtained as follows:

[0125]

[0126] R d This indicates the responsivity of the photodetector in the balanced receiving module.

[0127] Substituting E into the above formula CW (t)=A CW ·exp[i·(ω0t+φ0+φ N (t))] and We can obtain:

[0128]

[0129] After differentially dividing the I-channel signal and the Q-channel signal respectively, we get:

[0130]

[0131]

[0132] This corresponds to the case where k is even, i.e., the phase term in the above equation satisfies the following equation. have to:

[0133]

[0134] therefore:

[0135]

[0136] Then perform autocorrelation on Δφ(t) to find the time delay corresponding to the second peak of the correlation curve, which is the time delay mismatch Δt.

[0137] The second aspect of this application provides a method for testing the link delay of a chaotic module, including the following steps:

[0138] Select a continuous laser as the test carrier, and split the test carrier into beams, outputting one beam to the link system of the chaotic module under test;

[0139] Another test carrier is mixed with the output of the chaotic decryption device of the chaotic module link system under test by 90° to achieve self-zero difference coherent detection, and the mixed optical field is obtained. The mixed optical field is then converted by photoelectric conversion to output the Q component signal.

[0140] The input Q component signal is sampled at high speed, and the phase mismatch term is calculated. The phase mismatch term is then autocorrelated to obtain the correlation curve. The time delay corresponding to the second peak is calculated based on the correlation curve to obtain the measured time delay mismatch Δt. The phase mismatch term refers to the phase term generated by the light field output by the chaotic decryption device due to the time delay mismatch between the encryption link and the decryption link.

[0141] It is understood that in this embodiment, when searching for the delay mismatch Δt of the chaotic module link system, a known continuous laser is used as a test carrier (corresponding to the service carrier) to accurately calculate the delay mismatch Δt of the entire chaotic module link system. This allows the chaotic module link system to be adjusted subsequently using the delay mismatch Δt so that the delay mismatch Δt of the adjusted chaotic module link system meets the predetermined requirements.

[0142] In some embodiments, 90° mixing may include:

[0143] The output of the chaotic decryption device of the chaotic module link system under test is phase-shifted by kπ+π / 2 and then coherently mixed with the test carrier, where k is an integer.

[0144] As can be understood from the above explanation of the principle, k here can be a positive integer, 0, or a negative integer.

[0145] In some embodiments, when k is even, the method for calculating the phase mismatch term may include:

[0146]

[0147] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0148] Q(t) = Q p (t)-Q n (t)

[0149] Here, Q p (t) refers to the Q component signal in the Q component signal. p The electrical signal Q corresponding to the light field n (t) represents the Q component signal in the Q component signal. n The electrical signal corresponding to the light field.

[0150] When k is odd, the calculation method for the phase mismatch term may include:

[0151]

[0152] Where Δφ(t) refers to the phase mismatch term, R d A represents the responsivity of the photodetector in the balanced receiving module. CW A represents the amplitude of the optical field in a continuous laser beam. PM The amplitude of the optical field output from the output terminal of the chaotic decryption device in the tested chaotic module link system is represented by acos(), which represents the inverse cosine function. The calculation method for Q(t) is as follows:

[0153] Q(t) = Q p (t)-Q n (t)

[0154] Here, Q p(t) refers to the Q component signal in the Q component signal. p The electrical signal Q corresponding to the light field n (t) represents the Q component signal in the Q component signal. n The electrical signal corresponding to the light field.

[0155] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0156] It should be noted that the information interaction and execution process between the above-mentioned devices / units / modules are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0157] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0158] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a photographing device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. It should be noted that the content contained in the computer-readable medium may be appropriately added to or subtracted from the content as required by the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium may not include electrical carrier signals and telecommunication signals.

[0159] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0160] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0161] In the embodiments provided in this application, it should be understood that the disclosed apparatus / network devices and methods can be implemented in other ways. For example, the apparatus / network device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0162] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0163] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A chaotic module link latency test system, characterized by, The laser beam splitting module, the balanced coherent receiving module and the sampling analysis module, the first output end of the laser beam splitting module is used for connecting with the service carrier input end of the measured chaotic module link system, the second output end of the laser beam splitting module is connected with the second input end of the balanced coherent receiving module, the first input end of the balanced coherent receiving module is connected with the output end of the chaotic decryption device of the measured chaotic module link system, and the Q component output end of the balanced coherent receiving module is connected with the input end of the sampling analysis module; The laser beam splitting module, the balanced coherent receiving module and the sampling analysis module, the first output end of the laser beam splitting module is used for connecting with the service carrier input end of the measured chaotic module link system, the second output end of the laser beam splitting module is connected with the second input end of the balanced coherent receiving module, the first input end of the balanced coherent receiving module is connected with the output end of the chaotic decryption device of the measured chaotic module link system, and the Q component output end of the balanced coherent receiving module is connected with the input end of the sampling analysis module; The balanced coherent receiving module is used for performing 90° frequency mixing on the test carrier and the output of the chaotic decryption device of the measured chaotic module link system to realize self-zero difference coherent detection, obtaining mixed light field, and outputting Q component signals after photoelectric conversion of the mixed light field; The sampling analysis module is used for high-speed sampling of the input Q component signals, and obtaining phase mismatch items by calculation, and performing autocorrelation operation on the phase mismatch items to obtain a correlation curve, and calculating the time delay corresponding to the second peak of the correlation curve to obtain the measured time delay mismatch amount Δt.

2. The chaotic module link delay test system of claim 1, wherein, The sampling analysis module includes a high-speed sampling unit and a digital processing unit, the input end of the high-speed sampling unit is connected with the Q component output end of the balanced coherent receiving module, and the output end of the high-speed sampling unit is connected with the digital processing unit. The high-speed sampling unit is used for high-speed sampling of the Q component signals output by the Q component output end of the balanced coherent receiving module to obtain Q component digital signals. The digital processing unit is used for obtaining phase mismatch items by calculation according to the Q component digital signals obtained by high-speed sampling, and performing autocorrelation operation on the phase mismatch items to obtain a correlation curve, and calculating the time delay corresponding to the second peak of the correlation curve to obtain the measured time delay mismatch amount Δt.

3. The chaotic module link delay test system of claim 1, wherein, The Q component output end of the balanced coherent receiving module comprises Q p output end and Q n output end, the Q p output end is used for outputting Q p corresponding to the optical field, denoted as Q p (t);the Q n output end is used for outputting Q n corresponding to the optical field, denoted as Q n (t).

4. The chaotic module link delay test system of claim 3, wherein, The first input end of the balanced coherent receiving module is a signal light port, and the second input end of the balanced coherent receiving module is a local oscillator light port.

5. The chaotic module link delay test system of claim 4, wherein, The phase mismatch items obtained by calculation according to the Q component digital signals obtained by high-speed sampling include: wherein, Δ (t) is a phase mismatch term, R d represents the responsivity of the photoelectric conversion of the photodetector in the balanced receiving module, A CW represents the light field amplitude of the continuous laser, A PM represents the light field amplitude output by the output end of the chaotic decryption device of the measured chaotic module link system, acos() represents the inverse cosine function, and the calculation manner of the Q(t) is: 。 6. The chaotic module link delay test system of claim 3, wherein, The first input end of the balanced coherent receiving module is a local oscillator light port, and the second input end of the balanced coherent receiving module is a signal light port.

7. The chaotic module link delay test system of claim 6, wherein, The phase mismatch items obtained by calculation according to the Q component digital signals obtained by high-speed sampling include: wherein Δ (t) is a phase mismatch term, R d represents the responsivity of the photoelectric conversion of the photodetector in the balanced receiving module, A CW represents the light field amplitude of the continuous laser, A PM represents the light field amplitude output by the output end of the chaotic decryption device of the measured chaotic module link system, acos() represents an inverse cosine function, and the Q(t) is calculated in the following manner: 。 8. A method of testing for link delay in a chain of chaotic modules, characterized by, The method comprises the following steps: A continuous laser is selected as a test carrier, and the test carrier is split into two paths, one of which is output to the measured chaotic module link system; The other path of the test carrier is mixed with the output of the chaotic decryption device of the measured chaotic module link system to realize self-zero difference coherent detection, obtain mixed light field, and output Q component signals after photoelectric conversion of the mixed light field; The other path of the test carrier is mixed with the output of the chaotic decryption device of the measured chaotic module link system to realize self-zero difference coherent detection, obtain mixed light field, and output Q component signals after photoelectric conversion of the mixed light field; The input Q component signal is high-speed sampled, and a phase mismatch term is calculated, and autocorrelation operation is performed on the phase mismatch term to obtain a correlation curve, and then a time delay corresponding to a secondary peak of the correlation curve is calculated to obtain a measured time delay mismatch Δt; the phase mismatch term refers to a phase term generated by an optical field output by a chaotic decryption device due to time delay mismatch between an encryption link and a decryption link.

9. The chaotic module link delay test method of claim 8, wherein, The 90° mixing includes: The output of the chaotic decryption device of the measured chaotic module link system is subjected to kπ+π / 2 phase shift and then self-coherent mixing with a test carrier, wherein k is an integer.

10. The chaotic module link time delay test method of claim 9, wherein, when k is an even number, the operation method of the phase mismatch term includes: wherein Δ (t) is a phase mismatch term, R d represents the responsivity of the photoelectric conversion of the photodetector in the balanced receiving module, A CW represents the light field amplitude of the continuous laser, A PM represents the light field amplitude output by the output end of the chaotic decryption device of the measured chaotic module link system, acos() represents the inverse cosine function, and the calculation manner of the Q(t) is: Here, Q p (t) refers to the Q p component signal corresponding to the optical field, Q n (t) represents the Q n component signal corresponding to the optical field; when k is an odd number, the operation method of the phase mismatch term includes: wherein Δ (t) is a phase mismatch term, R d represents the responsivity of the photoelectric conversion of the photodetector in the balanced receiving module, A CW represents the light field amplitude of the continuous laser, A PM represents the light field amplitude output by the output end of the chaotic decryption device of the measured chaotic module link system, acos() represents the inverse cosine function, and the Q(t) is calculated in the following manner: Here, Q p (t) is the Q p component signal corresponding to the optical field, Q n (t) is the Q n component signal corresponding to the optical field.

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