Chaotic module link delay test system and method

Abstract

The invention relates to information technology. The invention aims to solve the problem that the time delay mismatch quantity cannot be accurately measured in the current chaos module link system, and provides a chaos module link time delay test system and method, and the technical scheme can be summarized as follows: a continuous laser is adopted as a test carrier, and the test carrier is subjected to beam splitting; one path is output to a chaos module link system to be tested; 90-degree frequency mixing is carried out on the other path of test carrier and the output of a chaos decryption device of the tested chaos module link system so as to realize self-homodyne coherent detection, a frequency mixing light field is obtained, and after photoelectric conversion is carried out on the frequency mixing light field, a Q component signal is output; the method comprises the following steps: performing high-speed sampling on an input Q component signal, performing operation to obtain a phase mismatch item, performing self-correlation operation on the phase mismatch item to obtain a correlation curve, and calculating time delay corresponding to a secondary peak according to the correlation curve to obtain a measured time delay mismatch amount delta t. The method has the beneficial effects that the measured time delay mismatch amount delta t can be quickly and accurately calculated, and the method is suitable for a chaos module link system.

Description

Technical Field

[0001] The present application relates to information technology, and in particular to a chaos module link delay test system and method. Background Art

[0002] In the chaotic module link system, it generally includes a service carrier input end, an encryption link, a decryption link and a chaotic decryption device. The service carrier input end is connected to the output end of the encryption link and the input end of the decryption link respectively. The output end of the encryption link and the output end of the decryption link are connected to the input end of the chaotic decryption device respectively. When it is used, the delay of the chaotic phase scrambling and descrambling operation applied to the service carrier needs to be strictly controlled so that when the chaotically scrambled service carrier is transmitted to the chaotic decryption device, the synchronized chaotic descrambling signal is also just transmitted to the chaotic decryption device. The transmission delay of the two needs to be accurately aligned, and the delay error should be less than 10ps. When a new chaotic module system is built, in order to achieve accurate delay matching of the chaotic phase scrambling and descrambling operations applied to the service carrier, it is necessary to accurately measure the delay mismatch Δt of the two. In the prior art, when calculating the above-mentioned delay mismatch Δt, the delay of each optical device or electrical device is measured separately, then accumulated in the corresponding optical path, and then the accumulated delay of the two optical paths is compared to finally estimate a delay mismatch Δt. However, since the delay of the photoelectric conversion device involved cannot be accurately measured, and the error of the delay of each device will also accumulate, the existing scheme for estimating the delay mismatch Δt is time-consuming and the measurement accuracy is not high (approximately 1 to 10ns).

[0003] Therefore, the prior art cannot accurately and quickly measure the delay mismatch Δt in the chaotic module link system. Summary of the invention

[0004] The purpose of this application is to solve the problem that it is currently impossible to accurately measure the delay mismatch in the chaotic module link system, and to provide a chaotic module link delay test system and method.

[0005] In the technical solution adopted by the present application to solve the above-mentioned technical problems, the first aspect provides a chaotic module link delay test system, including a laser beam splitting module, a balanced coherent receiving module and a sampling and analysis module, wherein the first output end of the laser beam splitting module is used to be connected to the service carrier input end of the chaotic module link system under test, the second output end of the laser beam splitting module is connected to the second input end of the balanced coherent receiving module, the first input end of the balanced coherent receiving module is connected to the output end of the chaotic decryption device of the chaotic module link system under test, and the Q component output end of the balanced coherent receiving module is connected to the input end of the sampling and analysis module;

[0006] The laser beam splitting module has an input end for inputting a continuous laser as a test carrier, and splits the test carrier and outputs it through the first output end and the second output end respectively;

[0007] The balanced coherent receiving module is used to perform 90° mixing on the test carrier and the output of the chaotic decryption device of the tested chaotic module link system to achieve self-homodyne coherent detection, obtain a mixed light field, and output a Q component signal after photoelectric conversion of the mixed light field;

[0008] The sampling and analysis module is used to perform high-speed sampling on the input Q component signal, calculate and obtain a phase mismatch term, and perform autocorrelation operation on the phase mismatch term to obtain a correlation curve, and then calculate the delay corresponding to the second peak according to the correlation curve to obtain the measured delay mismatch amount Δt; the phase mismatch term refers to the phase term generated by the light field output by the chaotic decryption device due to the 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 end of the high-speed oscilloscope unit is connected to the Q component output end of the balanced coherent receiving module, and the output end 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 on the Q component signal outputted from the Q component output terminal of the balanced coherent receiving module to obtain a Q component digital signal;

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

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

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

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

[0015]

[0016] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

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

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

[0020]

[0021] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

[0023] In the technical solution adopted by the present application to solve the above technical problems, a second aspect provides a chaotic module link delay test method, comprising the following steps:

[0024] A continuous laser is selected as a test carrier, and the test carrier is split and output to the chaotic module link system under test;

[0025] The other test carrier is mixed with the output of the chaotic decryption device of the chaotic module link system under test by 90 degrees to realize self-homodyne coherent detection, and a mixed light field is obtained, and the mixed light field is converted into a Q component signal after photoelectric conversion;

[0026] The input Q component signal is sampled at high speed, and a phase mismatch term is obtained by calculation. The phase mismatch term is autocorrelated to obtain a correlation curve, and then the delay corresponding to the second peak is calculated according to the correlation curve to obtain the measured 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 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 self-coherently mixed with the test carrier, where k is an integer.

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

[0030]

[0031] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

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

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

[0035]

[0036] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field.PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

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

[0039] The beneficial effect of the present application is that, in the scheme of the present application, a known continuous laser is input as a test carrier in the chaotic module link system under test, and the test carrier is mixed by 90° with the output of the chaotic decryption device of the chaotic module link system under test to realize self-zero difference coherent detection, so as to obtain a mixed light field, and the mixed light field is subjected to photoelectric conversion to output a Q component signal; the input Q component signal is sampled at a high speed, and a phase mismatch term is obtained by calculation, and an autocorrelation operation is performed on the phase mismatch term to obtain a correlation curve, and then the delay corresponding to the second peak is calculated according to the correlation curve to obtain the measured delay mismatch amount Δt. It can be seen that the whole scheme is simple and easy, and the calculated measured delay mismatch amount Δt is relatively accurate, which can reach the order of ~10ps, and provides corresponding delay mismatch amount Δt data for subsequent adjustment of the delay mismatch amount Δt of the chaotic module link system under test. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic system block diagram of the chaotic module link delay test system provided in the first aspect of the embodiment of the present application after being connected to the chaotic module link system under test. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In the following description, specific details such as specific system structures and technologies are proposed for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed description of well-known systems, devices, circuits and methods is omitted to prevent unnecessary details from hindering the description of the present application.

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

[0043] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0044] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0045] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0046] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0047] Figure 1A schematic system block diagram of the chaotic module link delay test system provided in the first aspect of an embodiment of the present application after being connected to the chaotic module link system under test is shown. As an example but not limitation, the chaotic module link delay test system includes a laser beam splitting module, a balanced coherent receiving module and a sampling and analysis module, wherein the first output end of the laser beam splitting module is used to be connected to the service carrier input end of the chaotic module link system under test, the second output end of the laser beam splitting module is connected to the second input end of the balanced coherent receiving module, the first input end of the balanced coherent receiving module is connected to the output end of the chaotic decryption device of the chaotic module link system under test, and the Q component output end of the balanced coherent receiving module is connected to the input end of the sampling and analysis module.

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

[0049] The balanced coherent receiving module is used to perform 90° mixing on the test carrier and the output of the chaotic decryption device of the chaotic module link system under test to realize self-homodyne coherent detection, obtain the mixed light field, and output the Q component signal after photoelectric conversion of the mixed light field.

[0050] The sampling and analysis module is used to perform high-speed sampling on the input Q component signal, calculate the phase mismatch term, and perform autocorrelation operation on the phase mismatch term to obtain a correlation curve, and then calculate the delay corresponding to the second peak according to the correlation curve to obtain the measured 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 delay mismatch between the encryption link and the decryption link.

[0051] It can be understood that in the chaotic module link delay test system, a known continuous laser is used as a test carrier, which is split by a laser beam splitting module and input to the chaotic module link system under test. After being chaotically scrambled and descrambled by the encryption link and the decryption link, the laser is output to the chaotic decryption device. The test carrier and the output of the chaotic decryption device of the chaotic module link system under test are mixed by 90° through a balanced coherent receiving module to achieve self-zero difference coherent detection to obtain a mixed light field. The mixed light field is converted into a photoelectric field and then outputted as a Q component signal. Finally, the sampling and analysis module performs high-speed sampling on the Q component signal, calculates a phase mismatch term, and performs autocorrelation on the phase mismatch term to obtain a correlation curve. The delay corresponding to the second peak is calculated according to the correlation curve to obtain the measured delay mismatch Δt.

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

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

[0054] Here, the high-speed oscilloscope unit is used to perform high-speed sampling on the Q component signal outputted from the Q component output terminal of the balanced coherent receiving module to obtain a Q component digital signal;

[0055] The digital processing unit is used to obtain a phase mismatch term based on the Q component digital signal obtained by high-speed sampling, and perform autocorrelation operation on the phase mismatch term to obtain a correlation curve, and then calculate the delay corresponding to the second peak based on the correlation curve to obtain the measured delay mismatch amount 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 preferentially, and a high-speed oscilloscope unit should be used for high-speed sampling, which can reduce errors and make the subsequent analysis and calculation results more accurate.

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

[0058] It can be understood that Q in the above embodiment p Output and Q n The output end is the corresponding output end in the existing balanced coherent receiver, which is a relatively mature technology in the prior art and will not be described in detail here.

[0059] Since the input end of the balanced coherent receiving module generally includes a signal optical port and a local oscillator optical port, in some embodiments, the first input end of the balanced coherent receiving module may be the signal optical port, and the second input end of the balanced coherent receiving module may be the local oscillator optical port.

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

[0061] When the first input end of the balanced coherent receiving module is a signal optical port, and the second input end of the balanced coherent receiving module is a local oscillator optical port, in some embodiments, the phase mismatch term obtained by calculating the Q component digital signal obtained by high-speed sampling may include:

[0062]

[0063] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

[0065] It can be understood that according to the above formula, we only need 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, and then an autocorrelation operation is performed on it to find the time delay corresponding to the secondary peak (minimum) of the corresponding curve, which is the required time delay mismatch Δt.

[0066] In addition, in some embodiments, the first input end of the balanced coherent receiving module can be set as a local oscillator optical port, and the second input end of the balanced coherent receiving module can be set as a signal optical port.

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

[0068] When the first input end of the balanced coherent receiving module is a local oscillator optical port, and the second input end of the balanced coherent receiving module is a signal optical port, in some embodiments, the phase mismatch term obtained by calculating the Q component digital signal obtained by high-speed sampling may include:

[0069]

[0070] Where Δφ(t) is the phase mismatch term, Rd A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

[0072] It can be understood that according to the above formula, we only need 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, and then an autocorrelation operation is performed on it to find the time delay corresponding to the secondary peak (minimum) of the corresponding curve, which is the required time delay mismatch Δt.

[0073] The principles of this application are as follows:

[0074] Assume that the light field emitted by a continuous laser CW can be expressed by the following formula:

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

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

[0077] After the light field passes through the chaotic perturbations of the encryption link and the decryption link, it can be expressed as follows when output from the chaotic decryption device:

[0078]

[0079] Among them, C A (t) and C B (t) represent the electrical signals of the chaotic encrypted light field (the light field input to the chaotic decryption device after passing through the encryption link) and the chaotic decrypted light field (the light field input to the chaotic decryption device after passing through the decryption link) after being detected by their respective photodetectors, V π is the half-wave voltage of the phase modulator used in the chaotic module link system, A PM Represents the amplitude of the light field outputted from the output end of the chaotic decryption device of the chaotic module link system under test.

[0080] Usually high-speed photodetectors have DC isolation characteristics, so C A (t) and C B (t) is an AC signal that fluctuates around 0, 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 (t)), max{} and min{} 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 incident light power to the photodetector pp , so that η PM ≤1.

[0086] So:

[0087]

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

[0089]

[0090] Among them, R d It represents the efficiency of photoelectric conversion (i.e., the responsivity of photoelectric conversion of the photodetector in the balanced receiving module). k can be any integer, including negative integers, 0 and positive integers.

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

[0092]

[0093] Among them, U(t) represents an intermediate quantity that is convenient for subsequent calculations, R d A CW 2 and R d A PM 2 Corresponding to E CW (t) and E PM (t) The detected electrical signal can be tested separately.

[0094] When k is an even number (including negative even numbers), according to the above formula And the periodicity of the cosine function can be obtained:

[0095]

[0096] So we have:

[0097]

[0098] When k is an odd number (including negative odd numbers), according to the above formula And the periodicity of the cosine function can be obtained:

[0099]

[0100] So we have:

[0101]

[0102] Also because C A (t-Δt) and C B (t) is a chaotic synchronization signal with a very high correlation coefficient (usually the correlation coefficient reaches more than 92%), so the autocorrelation operation is performed on Δφ(t), and the delay corresponding to the secondary peak of the corresponding correlation curve is the delay mismatch Δt. At the same time, because C A (t-Δt) and C B (t) are in a subtractive relationship, so this secondary peak should have the characteristic of being concave downward (minimum value).

[0103] In reality, a coherent receiver can be conveniently used to achieve a phase shift of ±π / 2. Usually, a coherent receiver adopts a balanced detection method, that is, a balanced coherent receiver, which can further improve the signal-to-noise ratio.

[0104] Assume a balanced coherent receiver, the transmission function S of its light field is:

[0105]

[0106] E PM (t) and E CW (t) Input the signal optical port (S port) and the local oscillator optical port (LO port) of the balanced coherent receiver for mixing, and four optical fields will be obtained, which are expressed as follows:

[0107]

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

[0109]

[0110] Rd Represents the responsivity of the photoelectric conversion of the photodetector in the balanced receiving module.

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

[0112] We can get:

[0113]

[0114] After differentiating the I-channel signal and the Q-channel signal, we get:

[0115]

[0116] At this time, it corresponds to the case where k is an odd number, that is, the phase term in the above formula satisfies the formula

[0117] have to:

[0118]

[0119] therefore:

[0120]

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

[0122] At the same time, the input optical field of the local oscillator optical port and the signal optical port can be exchanged, that is, E PM (t) and E CW (t) The signals are input into the local oscillator optical port (LO port) and the signal optical port (S port) of the balanced coherent receiver for mixing. At this time, four optical fields are obtained, which are expressed as follows:

[0123]

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

[0125]

[0126] R d Represents the responsivity of the photoelectric conversion of the photodetector in the balanced receiving module.

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

[0128]

[0129] After differentiating the I-channel signal and the Q-channel signal, we get:

[0130]

[0131]

[0132] At this time, it corresponds to the case where k is an even number, that is, the phase term in the above formula satisfies the formula have to:

[0133]

[0134] therefore:

[0135]

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

[0137] A second aspect of an embodiment of the present application provides a chaotic module link delay test method, comprising the following steps:

[0138] A continuous laser is selected as a test carrier, and the test carrier is split and output to the chaotic module link system under test;

[0139] The other test carrier is mixed with the output of the chaotic decryption device of the chaotic module link system under test by 90 degrees to realize self-homodyne coherent detection, and a mixed light field is obtained, and the mixed light field is converted into a Q component signal after photoelectric conversion;

[0140] The input Q component signal is sampled at high speed, and a phase mismatch term is obtained by calculation. The phase mismatch term is autocorrelated to obtain a correlation curve. The delay corresponding to the second peak is calculated based on the correlation curve to obtain the measured 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 delay mismatch between the encryption link and the decryption link.

[0141] It can be understood that when this embodiment is looking 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, so that the chaotic module link system can be adjusted subsequently according to 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 self-coherently mixed with the test carrier, where k is an integer.

[0144] It can be understood that, referring to the above principle description, k here can be a positive integer, 0 or a negative integer.

[0145] In some embodiments, when k is an even number, the calculation method of the phase mismatch term may include:

[0146]

[0147] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

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

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

[0151]

[0152] Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is:

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

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

[0155] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean 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 the present application.

[0156] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units / modules are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0157] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by 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 embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0158] If the integrated unit is implemented in the form of 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, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device that can carry the computer program code to the camera device / terminal device, recording medium, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, a mobile hard disk, a disk or an optical disk. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media does not include electrical carrier signals and telecommunication signals.

[0159] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0160] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0161] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

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

[0163] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. Chaotic module link delay test system, characterized in that: It comprises a laser beam splitting module, a balanced coherent receiving module and a sampling and analysis module, wherein the first output end of the laser beam splitting module is used to be connected to the service carrier input end of the chaotic module link system under test, the second output end of the laser beam splitting module is connected to the second input end of the balanced coherent receiving module, the first input end of the balanced coherent receiving module is connected to the output end of the chaotic decryption device of the chaotic module link system under test, and the Q component output end of the balanced coherent receiving module is connected to the input end of the sampling and analysis module; The laser beam splitting module has an input end for inputting a continuous laser as a test carrier, and splits the test carrier and outputs it through the first output end and the second output end respectively; The balanced coherent receiving module is used to perform 90° mixing on the test carrier and the output of the chaotic decryption device of the tested chaotic module link system to achieve self-homodyne coherent detection, obtain a mixed light field, and output a Q component signal after photoelectric conversion of the mixed light field; The sampling and analysis module is used to perform high-speed sampling on the input Q component signal, calculate and obtain a phase mismatch term, and perform autocorrelation operation on the phase mismatch term to obtain a correlation curve, and then calculate the delay corresponding to the second peak according to the correlation curve to obtain the measured delay mismatch amount Δt; the phase mismatch term refers to the phase term generated by the light field output by the chaotic decryption device due to the delay mismatch between the encryption link and the decryption link.

2. The chaotic module link delay test system according to claim 1, characterized in that: The sampling and analysis module includes a high-speed oscilloscope unit and a digital processing unit, the input end of the high-speed oscilloscope unit is connected to the Q component output end of the balanced coherent receiving module, and the output end of the high-speed oscilloscope unit is connected to the digital processing unit; The high-speed oscilloscope unit is used to perform high-speed sampling on the Q component signal outputted from the Q component output terminal of the balanced coherent receiving module to obtain a Q component digital signal; The digital processing unit is used to obtain a phase mismatch term based on the Q component digital signal obtained by high-speed sampling, and perform autocorrelation operation on the phase mismatch term to obtain a correlation curve, and then calculate the delay corresponding to the second peak based on the correlation curve to obtain the measured delay mismatch amount Δt.

3. The chaotic module link delay test system according to claim 1, characterized in that: The Q component output terminal of the balanced coherent receiving module includes Q p Output and Q n The output terminal, the Q p Output terminal for output Q p The electrical signal corresponding to the light field is denoted as Q p (t); Q n Output terminal for output Q n The electrical signal corresponding to the light field is denoted as Q n (t).

4. The chaotic module link delay test system as claimed in claim 3, characterized in that: The first input end of the balanced coherent receiving module is a signal optical port, and the second input end of the balanced coherent receiving module is a local oscillator optical port.

5. The chaotic module link delay test system as claimed in claim 4, characterized in that: The phase mismatch term obtained by calculating the Q component digital signal obtained by high-speed sampling includes: Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is: Q(t)=Q p (t)-Q n (t)。 6. The chaotic module link delay test system as claimed in claim 3, characterized in that: The first input end of the balanced coherent receiving module is a local oscillator optical port, and the second input end of the balanced coherent receiving module is a signal optical port.

7. The chaotic module link delay test system according to claim 6, characterized in that: The phase mismatch term obtained by calculating the Q component digital signal obtained by high-speed sampling includes: Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is: Q(t)=Q p (t)-Q n (t)。 8. Chaos module link delay test method, characterized in that: The following steps are involved: A continuous laser is selected as a test carrier, and the test carrier is split and output to the chaotic module link system under test; The other test carrier is mixed with the output of the chaotic decryption device of the chaotic module link system under test by 90 degrees to realize self-homodyne coherent detection, and a mixed light field is obtained, and the mixed light field is converted into a Q component signal after photoelectric conversion; The input Q component signal is sampled at high speed, and a phase mismatch term is obtained by calculation. The phase mismatch term is autocorrelated to obtain a correlation curve, and then the delay corresponding to the second peak is calculated according to the correlation curve to obtain the measured 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 delay mismatch between the encryption link and the decryption link.

9. The chaotic module link delay test method according to claim 8, characterized in that: The 90° mixing includes: The output of the chaotic decryption device of the chaotic module link system under test is phase-shifted by kπ+π / 2 and then self-coherently mixed with the test carrier, where k is an integer.

10. The chaotic module link delay test method according to claim 9, characterized in that: When k is an even number, the calculation method of the phase mismatch term includes: Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is: Q(t)=Q p (t)-Q n (t) Here, Q p (t) refers to the Q component signal Q p The electrical signal corresponding to the light field, Q n (t) represents the Q component signal Q n The electrical signal corresponding to the light field; When k is an odd number, the calculation method of the phase mismatch term includes: Where Δφ(t) is the phase mismatch term, R d A represents the responsiveness of the photoelectric conversion of the photodetector in the balanced receiving module. CW A represents the amplitude of the continuous laser light field. PM represents the light field amplitude outputted from the output end of the chaotic decryption device of the chaotic module link system under test, acos() represents the arccosine function, and the calculation method of Q(t) is: Q(t)=Q p (t)-Q n (t) Here, Q p (t) refers to the Q component signal Q p The electrical signal corresponding to the light field, Q n (t) represents the Q component signal Q n The electrical signal corresponding to the light field.

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