Optical polarization multiplexing communication and interference integrated system with adjustable security level

Abstract

The invention discloses an optical polarization multiplexing communication and interference integrated system with an adjustable security level, and belongs to the field of security optical communication and microwave photons.The system divides an optical carrier into an upper branch and a lower branch which are injected into a signal modulation module and a carrier modulation module respectively; a received radar signal and an encrypted communication signal are respectively modulated on an X / Y polarization state of an upper branch optical carrier through a signal modulation module, and a Doppler signal and an up-conversion signal are respectively modulated on an X / Y polarization state of a lower branch optical carrier through a carrier modulation module; modulating signals of the upper branch and the lower branch are combined and then injected into an optical fiber loop to carry out range deception level adjustment on radar signals and encryption level adjustment on communication signals; and the adjusted signal is injected into the signal processing and transmitting module and is split into a radar interference signal and a safety communication signal to be transmitted. According to the invention, integration of radar interference and safety communication functions can be realized in a full optical domain, multi-level compatibility of interference and safety communication is realized, and the method is suitable for electronic countermeasure, wireless communication and other scenes.

Description

Technical Field

[0001] The present invention belongs to the field of secure optical communications and microwave photonics, and more particularly, relates to an optical polarization multiplexing communication and interference integrated system with adjustable security levels. Background Art

[0002] With the increasing complexity of the electromagnetic environment and the rapid development of electronic countermeasures, various jamming methods have been proposed to target unauthorized radar signals. These include noise masking, delay deception, and frequency shift deception. These methods can suppress noise, deceive distance, and deceive speed, effectively preventing unauthorized parties from locking onto targets and extracting information. Furthermore, to ensure the security of legitimate data communications, various encryption methods have been proposed, including quantum key distribution, chaotic encryption, and quantum noise stream encryption (QNSC). These methods, using encryption algorithms and keys, can transform communication information into encrypted information. Even if intercepted, unauthorized parties cannot decipher the information due to lack of the key.

[0003] Current jamming and security communication systems are typically based on digital systems. Limited by the sampling rates of components like DACs and ADCs, their operating frequency bands and bandwidths face "electronic bottlenecks." With the development of millimeter-wave technology, radar and communication applications are gradually expanding from low-frequency bands to high-frequency bands. Digital jamming and communication systems struggle to cover these expanding frequency bands.

[0004] In addition, the jamming systems and security communication systems currently used are usually separate in technology and structure, which is not conducive to system integration and resource sharing. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the existing technology, the present invention provides an integrated optical polarization multiplexing communication and interference system with adjustable security level. Its purpose is to use microwave photonic technology to realize multi-level compatible security communication and radar interference integrated design in the entire optical domain, and solve the current problems of limited working frequency bands and bandwidths of security communication and interference, low system integration, and difficult security adjustment.

[0006] To achieve the above objectives, according to a first aspect of the present invention, there is provided an integrated optical polarization multiplexing communication and jamming system with adjustable security level, comprising:

[0007] A seed light generating module, configured to equally divide the optical carrier into a first optical carrier and a second optical carrier;

[0008] a signal modulation module, configured to modulate the radar signal onto a first polarization state of the first optical carrier to obtain a radar modulation signal, modulate the encrypted communication signal onto a second polarization state of the first optical carrier to obtain a communication modulation signal, and combine the two to obtain a modulation signal a; wherein the first polarization state is one of an X polarization state and a Y polarization state, and the second polarization state is the other of the X polarization state and the Y polarization state;

[0009] The carrier modulation module is used to modulate the Doppler signal on the first polarization state of the second optical carrier to obtain a radar modulated carrier, modulate the up-converted signal on the second polarization state of the second optical carrier to obtain a communication modulated carrier, and combine the two to obtain a modulated carrier b;

[0010] A security level adjustment module includes an optical combiner, an input optical switch, an optical fiber loop, a polarization controller, and a first control module; the optical combiner is used to combine signals a and b to obtain signal c, and the optical fiber loop includes an optical coupler, an optical amplifier, a delay optical fiber, and a loop optical switch; the first control module is used to control the input optical switch to be turned on to allow signal c to enter the optical coupler; the first control module is also used to control the loop optical switch to be turned on, so that after signal c enters the optical coupler, a portion passes through the optical amplifier, the delay optical fiber, and the loop optical switch and then re-enters the optical coupler for continuous circulation, while the other portion enters the polarization controller for polarization state restoration to obtain the target signal; the delay optical fiber is used to provide a delay for radar distance deception, and the optical amplifier is used to compensate for the loss of the optical coupler and optical fiber, while providing ASE noise to mask the encrypted signal and increase the encryption level of the communication signal; the first control module controls the number of cycles of signal c in the optical fiber loop by controlling the connection time of the input optical switch and the loop optical switch, thereby obtaining different levels of radar signal distance deception and communication signal encryption levels;

[0011] Among them, the number of cycles N of the signal c in the optical fiber loop and the distance deception amount of the radar signal satisfy the relationship: Δτ is the delay of each optical fiber loop, c is the speed of light in the optical fiber; N and the noise increment of the communication signal satisfy the relationship ΔP N (f) = 2N(G-1)n sp hν,G、n sp are the gain and spontaneous emission coefficient of the optical amplifier, h is the Planck constant, and ν is the photon frequency;

[0012] The signal processing and transmission module is used to obtain the interference signal d in the electrical domain by beating the radar modulation signal and the radar modulation carrier in the target signal and send it, and to obtain the encrypted communication signal e in the electrical domain by beating the communication modulation signal and the communication modulation carrier in the target signal and send it.

[0013] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0014] 1. The present invention provides an integrated optical polarization multiplexing communication and jamming system with adjustable security levels. Based on microwave photonic technology, it achieves an integrated design for radar jamming and secure communications across the entire optical domain. This expands the system's operating frequency band and bandwidth, enabling millimeter-wave secure communications and jamming of millimeter-wave radar signals. Due to the advantages of optoelectronic integration, the system boasts a compact structure, making it suitable for deployment in a variety of flexible electronic countermeasures scenarios. Furthermore, the system utilizes optical polarization multiplexing to process and transmit radar jamming signals and secure communication signals. In the optical fiber link, radar and communication signals are modulated at different frequency bands, effectively avoiding polarization crosstalk damage. The jamming and communication signals emitted by the signal processing and transmission module can be transmitted simultaneously and at the same frequency, conserving wireless channel resources. Furthermore, the system utilizes optical fiber loops to adjust security levels. For radar jamming, it can achieve varying levels of distance deception and distance-pushing jamming. For secure communications, it can increase noise masking, making it more difficult for unauthorized parties to decipher the key, and achieve varying levels of encryption. The multi-level compatibility of radar jamming and secure communications significantly improves the system's security performance.

[0015] 2. The present invention provides an integrated optical polarization multiplexing communication and jamming system with adjustable security level. The Doppler signal used can be a sawtooth wave signal or a high-power single-tone signal. By programming and adjusting the form of the Doppler signal, single-false target frequency shift interference and multiple-false target frequency shift interference can be achieved respectively. Combined with an optical fiber loop, distance-speed joint interference can be achieved. The multi-dimensional and multi-functional interference further improves the interference performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram of an integrated optical polarization multiplexing communication and interference system with adjustable security level provided by the present invention.

[0017] Figure 2 is a spectrum diagram of each node in the system in Example 1 of the present invention; wherein, Figure 2 (a) to (e) represent Figure 1 The spectrum of signals a~e in.

[0018] Figure 3 is a simulation result diagram provided by Example 1 of the present invention; wherein, Figure 3 (a) to (c) in the figure represent the frequency spectrum of the interference signal d when the delay is 0μs, 500μs, and 1000μs, respectively.

[0019] Figure 4 is a simulation result diagram provided by Example 1 of the present invention; wherein, Figure 4(a) to (c) in the figure represent the spectrum of the encrypted communication signal e intercepted by the illegal party when the delay is 0μs, 250μs, and 500μs, respectively. Figure 4 (d) to (f) in the figure represent the frequency spectra of the communication signal e decrypted by the legitimate party when the delay is 0μs, 250μs, and 500μs, respectively.

[0020] Figure 5 is a spectrum diagram of each node in the system in embodiment 2 of the present invention; wherein, Figure 5 (a) to (e) represent Figure 1 The spectrum of signals a~e in the figure. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0022] Microwave photonics technology offers advantages such as high frequency, wide bandwidth, low loss, and strong resistance to electromagnetic interference. It can be used to overcome existing electronic bottlenecks and build jamming and communication systems in the millimeter-wave frequency band. Furthermore, microwave photonics technology possesses a rich physical dimension and can process multiple signals through time-division multiplexing, wavelength-division multiplexing, polarization-division multiplexing, and space-division multiplexing, making it ideally suited for the integrated design of jamming and secure communication systems and functions.

[0023] Based on this, the embodiment of the present invention provides an optical polarization multiplexing communication and interference integrated system with adjustable security level, such as Figure 1 Shown, including:

[0024] The seed light generating module is used to equally divide the optical carrier into the first and second optical carriers.

[0025] The seed light generating module includes an optical beam splitter, which is used to equally divide the optical carrier into two upper and lower branches, namely the first and second optical carriers.

[0026] Preferably, the seed light generating module further includes a laser for generating an optical carrier.

[0027] A signal modulation module is used to modulate the radar signal on a first polarization state of a first optical carrier to obtain a radar modulation signal, modulate the encrypted communication signal on a second polarization state of the first optical carrier to obtain a communication modulation signal, and combine the radar modulation signal and the communication modulation signal to obtain a modulation signal a; wherein the first polarization state is one of the X and Y polarization states, and the second polarization state is the other of the X and Y polarization states.

[0028] The following description is made by taking an example where the first polarization state is an X polarization state and the second polarization state is a Y polarization state.

[0029] The signal modulation module is used to modulate the received radar signal and the encrypted security communication signal on the X and Y polarization states of the upper branch optical carrier (i.e., the first optical carrier) respectively in a one-to-one correspondence;

[0030] The signal modulation module includes a receiving antenna and a dual-polarization dual parallel Mach-Zehnder modulator (DP-DPMZM);

[0031] The receiving antenna is used to receive enemy radar signals. The DP-DPMZM includes a first optical polarization beam splitter, a DPMZM-X, a DPMZM-Y, and a first optical polarization beam combiner. The first optical polarization beam splitter is used to split the upper branch optical carrier into two optical carriers with X and Y polarization states. Both the DPMZM-X and DPMZM-Y use carrier suppressed single-sideband modulation.

[0032] The received radar signal is modulated onto an optical carrier in the X-polarization state through DPMZM-X. The resulting radar modulated signal is expressed as:

[0033]

[0034] Among them, A radar1 (t) is the amplitude of the radar modulation signal, f c and f radar are the optical carrier frequency and the radar signal center frequency respectively.

[0035] The encrypted secure communication signal is modulated onto the baseband of the Y-polarization optical carrier via DPMZM-Y. The resulting communication modulation signal is expressed as:

[0036]

[0037] Among them A comm.1 (t) is the amplitude of the communication modulation signal. The first optical polarization combiner is used to combine the radar modulation signal in the X polarization state with the communication modulation signal in the Y polarization state to obtain a modulation signal a.

[0038] The encryption method for the secure communication signal is quantum noise stream encryption (QNSC) or noise-like encryption. Taking QNSC as an example, a plaintext signal and a key signal are generated through digital signal synthesis. The key signal is used to perform a high-order mapping of the plaintext signal to produce a higher-order encrypted signal. The legitimate recipient uses the shared key to recover the original plaintext signal. However, an illicit recipient, lacking the key, cannot extract the plaintext signal obscured by quantum noise. The illicit recipient must fully decipher the encryption algorithm and key to recover the original plaintext signal.

[0039] The carrier modulation module is used to modulate the Doppler signal on the first polarization state of the second optical carrier to obtain a radar modulated carrier, modulate the up-converted signal on the second polarization state of the second optical carrier to obtain a communication modulated carrier, and combine the radar modulated carrier and the communication modulated carrier to obtain a modulated carrier b.

[0040] The carrier modulation module includes a dual-polarization dual-drive Mach-Zehnder modulator (DP-DDMZM). The DP-DDMZM includes a second optical polarization beam splitter, DDMZM-X, DDMZM-Y, and a second optical polarization beam combiner. The second optical polarization beam splitter is used to split the lower branch optical carrier (i.e., the second optical carrier) into two optical carriers in X and Y polarization states. The Doppler signal used for frequency shift deception is modulated onto the optical carrier in the X polarization state by the DDMZM-X to obtain a radar modulated carrier. The up-converted signal is modulated onto the optical carrier in the Y polarization state by the DDMZM-Y to obtain a communication modulated carrier. The second optical polarization beam combiner is used to combine the radar modulated carrier in the X polarization state with the communication modulated carrier in the Y polarization state to obtain a modulated carrier b.

[0041] The Doppler signal is a sawtooth wave signal or a high-power single-tone signal.

[0042] When the Doppler signal is a sawtooth wave signal, the radar modulated carrier is expressed as:

[0043]

[0044] Among them, A radar2 (t) is the amplitude of the radar modulated carrier, f d is the Doppler signal frequency, expressed as: A SAW is the amplitude of the sawtooth wave signal, T SAW is the sawtooth wave signal period, V π is the half-wave voltage of the modulator.

[0045] When the Doppler signal is a high-power single-tone signal, the radar modulated carrier is expressed as:

[0046]

[0047] Among them, f d is the frequency of a single tone signal.

[0048] The up-converted signal is a single-tone signal. The communication modulated carrier obtained is expressed as:

[0049]

[0050] Among them, A comm.2 (t) is the amplitude of the communication modulation carrier, f comm.is the frequency of a single tone signal.

[0051] A security level adjustment module includes an optical combiner, an input optical switch, an optical fiber loop, a polarization controller, and a first control module. The optical combiner is used to combine signals a and b to obtain signal c. The optical fiber loop includes an optical coupler, an optical amplifier, a delay optical fiber, and a loop optical switch. When the input optical switch is turned on, signal c enters the optical coupler. When signal c has completely entered, the loop optical switch is turned on. A portion of signal c entering the optical coupler passes through the optical amplifier, the delay optical fiber, and the loop optical switch and then re-enters the optical coupler for continuous circulation. Another portion enters the polarization controller for polarization state restoration to obtain a target signal. The delay optical fiber is used to provide a delay for radar range deception. The optical amplifier is used to compensate for losses in the optical coupler and optical fiber, while providing ASE noise to mask the encrypted signal and increase the encryption level of the communication signal. The first control module controls the number of cycles of the control signal c in the optical fiber loop by controlling the on-time of the input optical switch and the loop optical switch, thereby obtaining different levels of delay and ASE noise, corresponding to different levels of radar signal range deception and communication signal encryption.

[0052] Specifically, the optical combiner is used to combine modulated signal a and modulated carrier b to produce signal c. The fiber loop includes an optical coupler, an optical amplifier, a delay fiber, and a loop optical switch. The first control module controls the connection of the input optical switch and the loop optical switch to control signal c to enter the fiber loop at a specified time. The optical coupler is a 1:1 optical coupler that couples signal c into the optical fiber. Half of the optical signal input to the coupler participates in the fiber loop, while the other half enters the polarization controller, which aligns its polarization state with that of the third polarization beam splitter in the signal transmission module. The delay fiber is used to provide delay for radar range spoofing. The optical amplifier is used to compensate for losses in the optical coupler and optical fiber, while also providing ASE noise. ASE noise is used to mask encrypted signals, making it more difficult for unauthorized receivers to decipher the encryption key and thus increasing the level of communication signal encryption. The polarization controller is used to restore the polarization state of signal c. By controlling the number of times signal c circulates in the fiber loop, different levels of delay and ASE noise can be achieved, corresponding to different levels of radar signal range spoofing and communication signal encryption.

[0053] Among them, the number of cycles N of the signal c in the optical fiber loop and the distance deception amount of the radar signal satisfy the relationship: Δτ is the delay of each optical fiber loop, and c is the speed of light in the optical fiber;

[0054] The number of cycles N of the signal c in the optical fiber loop and the noise increment of the communication signal (a sign of increased encryption) satisfy the relationship ΔP N (f) = 2N(G-1)nsp hν,G、n sp are the gain and spontaneous emission coefficient of the optical amplifier, h is the Planck constant, and ν is the photon frequency;

[0055] In particular, for a QNSC signal, the increment of the number of cycles N of the signal c in the optical fiber loop and the noise masking signal number (NMS) of the communication signal (a parameter specifically used to evaluate the degree of QNSC encryption) is: in, is the PD responsivity, P LO is the communication modulated carrier optical power, B is the communication modulated signal bandwidth, P s is the optical power of the communication modulation signal, and M is the QNSC signal order.

[0056] Preferably, the optical fiber loop further comprises an optical filter, which is placed between the loop optical switch and the delay optical fiber and is used to filter out-of-band ASE noise to avoid saturation of the optical amplifier.

[0057] Preferably, the first control module is further configured to control the input optical switch to be turned off to reduce optical power while controlling the loop optical switch to be turned on.

[0058] The signal processing and transmission module is used to obtain the interference signal d in the electrical domain by beating the radar modulation signal and the radar modulation carrier in the target signal and send it, and to obtain the encrypted communication signal e in the electrical domain by beating the communication modulation signal and the communication modulation carrier in the target signal and send it.

[0059] It can be understood that the encrypted communication signal loaded on the second polarization state of the first optical carrier is a baseband signal with a center frequency of 0; the encrypted communication signal e transmitted by the signal processing and transmission module is an encrypted communication signal after up-conversion with a center frequency of f comm. .

[0060] Specifically, the signal processing and transmission module includes an optical polarization beam splitter (i.e., a third optical polarization beam splitter), a radar jamming signal transmission front end, and a communication signal transmission front end. The third optical polarization beam splitter is used to split the security-level-adjusted signal c (i.e., the target signal) into two signals in X and Y polarization states; the X polarization state signal includes a radar modulated signal and a radar modulated carrier, and the Y polarization state signal includes a communication modulated signal and a communication modulated carrier.

[0061] The radar jamming signal transmitting front end includes:

[0062] an interference light detector, configured to obtain an interference signal d in the electrical domain by beating the radar modulated signal in the first polarization state with the radar modulated carrier;

[0063] An interference transmitting antenna, used for transmitting an interference signal d;

[0064] The communication signal transmission front end includes:

[0065] a communication optical detector, configured to obtain an encrypted communication signal e in the electrical domain by beating the communication modulated signal in the second polarization state with the communication modulated carrier;

[0066] The communication transmitting antenna is used to send the encrypted communication signal e.

[0067] Preferably, the radar jamming signal transmitting front end further includes a second control module, an interference optical switch and a communication optical switch;

[0068] The second control module controls the interference light switch to allow the radar modulated signal and the radar modulated carrier to enter the interference light detector at a specified time;

[0069] The second control module controls the communication optical switch to allow the communication modulation signal and the communication modulation carrier to enter the interference light detector at a specified time.

[0070] Preferably, the interference signal transmitting front end further includes: an interference light attenuator arranged between the interference light switch and the interference light detector; the communication signal transmitting front end further includes: a communication light attenuator arranged between the communication light switch and the communication light detector.

[0071] That is, the interference light switch is used to control the X-polarization state signal to enter the transmitting front end at a specified time; the interference light attenuator is used to adjust the power injected into the light detector; the interference light detector is used to beat the radar modulated signal and the radar modulated carrier to generate an interference signal d in the electrical domain.

[0072] When the Doppler signal is a sawtooth wave, the interference signal d is expressed as:

[0073] I radar (t) = A radar (t)exp[j2π(f radar -f d )t];

[0074] At this time, the interference signal d contains a false target with a high harmonic suppression ratio at the same time, and the frequency shift deception is f d .

[0075] When the Doppler signal is a single-tone signal, the interference signal d is expressed as:

[0076]

[0077] At this time, the interference signal d contains multiple false targets at the same time, and the frequency shift deception is nf d, n∈Z. The interference transmitting antenna is used to transmit the interference signal d in the form of a wireless signal.

[0078] The structure and function of the communication signal transmitting front end are similar to those of the radar jamming signal transmitting front end, and are used to beat the communication modulation signal and the communication modulation carrier in the Y polarization state signal at a specified time to generate an encrypted communication signal e in the electric domain, which is expressed as: comm. (t) = A comm. (t)exp(j2πf comm. t), and transmits the encrypted communication signal e in the form of a wireless signal at the specified time.

[0079] The encrypted communication signal e is decrypted and demodulated at the receiver end that receives the encrypted communication signal e.

[0080] Example 1: Integration of single false target jamming and secure communications

[0081] In this embodiment, in the seed light generation module, the optical carrier generated by the laser is divided into two branches, upper and lower, by an optical beam splitter. In the signal modulation module, the upper branch optical carrier is injected into DP-DPMZM. The radar signal frequency is 36GHz, the pulse length is 2.5μs, and the period is 5ms. It is modulated on the optical carrier in the X polarization state through DPMZM-X. The communication signal bandwidth is 4GHz, the modulation format is 16QAM, and it is mapped to 2 through the QNSC algorithm. 16The QAM encrypted signal has a signal length of 2.5 μs. The encrypted communication signal is modulated onto a baseband optical carrier in the Y polarization state using DPMZM-Y. In the carrier modulation module, the downlink optical carrier is injected into the DP-DDMZM. ​​The Doppler signal is a sawtooth signal with a Doppler frequency of 32 MHz and is modulated onto an optical carrier in the X polarization state using DDMZM-X. The upconverted signal has a frequency of 36 GHz and is modulated onto an optical carrier in the Y polarization state using DDMZM-Y. In the security level adjustment module, the modulated signal a output by the DP-DPMZM and the modulated carrier b output by the DP-DDMZM are combined into a beam combiner to produce signal c. When the input optical switch is turned on, signal c enters the optical coupler. When signal c has fully entered, the loop optical switch is turned on, and the input optical switch is turned off. The delay fiber in the optical loop is a 500 m standard single-mode fiber with a delay of 2.5 μs. The noise figure of the optical amplifier is 4 dB. Signal c circulates different times in the optical fiber loop, which can obtain different levels of delay and ASE noise, corresponding to different levels of radar signal distance deception and communication signal encryption. In the signal processing and transmission module, the signal c, which has been adjusted for security level, is divided into two signals in X / Y polarization states by a third optical polarization beam splitter. The interference optical switch is turned on at a set of specified times. At this time, the radar modulation signal and the radar modulation carrier in the X polarization state signal beat the frequency to obtain the interference signal d and transmit it. The frequency of the interference signal d is 35.968 GHz, which contains distance-speed composite deception information. The communication optical switch is turned on at another set of specified times (it can be turned on at the same time as the interference optical switch). At this time, the communication modulation signal and the communication modulation carrier in the Y polarization state signal beat the frequency to obtain the communication signal e and transmit it. The center frequency of the communication signal e is 36 GHz. The signal spectrum of each node of the system in this embodiment is as follows Figure 2 As shown in (a) to (e).

[0082] This embodiment was simulated and analyzed based on VPI transmission Maker and MATLAB software. The characteristics of this method will be illustrated based on the following sets of simulation results:

[0083] Figure 3 is a simulation result diagram provided by Example 1 of the present invention, wherein: Figure 3 (a) to (c) represent the frequency spectra of the interference signal d at delays of 0μs, 500μs, and 1000μs, respectively. In the distance deception dimension, 400 levels of interference signals can be generated without significant degradation in power and signal-to-noise ratio. In the speed deception dimension, the interference signal produces a frequency shift equal to the Doppler frequency compared to the initial radar signal, and the harmonic suppression ratio of the false target is always higher than 28dB. Combined with delay deception, a high-quality distance-speed composite deception false target can be generated. It should be noted that the present invention is applicable to different radar signal frequencies or Doppler frequencies, and is not limited to the relevant parameters used in this embodiment.

[0084] Figure 4 is a simulation result diagram provided by Example 1 of the present invention, wherein: Figure 4 (a) to (c) in the figure represent the spectrum of the encrypted communication signal e intercepted by the illegal party when the delay is 0μs, 250μs, and 500μs, respectively. Figure 4 (d) to (f) represent the spectrum of the communication signal e decrypted by the legitimate party at delays of 0μs, 250μs, and 500μs, respectively. 200 levels of communication signal encryption can be generated. The noise masking number (NMS) of the encrypted signal intercepted by the illegal party increases with the number of cycles, making it increasingly difficult for the illegal party to decipher the key. The vector error magnitude (EVM) of the communication signal recovered by the legitimate party after decryption is less than 10%, and the bit error rate is lower than the hard judgment line of 3.8e-8, indicating consistently good communication quality. It should be noted that the present invention is applicable to different communication signal frequencies, bandwidths, and modulation formats, and is not limited to the relevant parameters used in this embodiment.

[0085] Example 2: Integration of multiple false target jamming and secure communications

[0086] In this embodiment, the Doppler signal is a high-power single-tone signal with a frequency of 32MHz. The rest of the system structure and parameter settings are the same as those in Example 1. In the signal processing and transmission module, the interference signal d obtained contains multiple false targets with a frequency of (36+n×0.032)GHz, n∈Z, and contains distance-speed composite deception information. The center frequency of the obtained communication signal e is 36GHz. The signal spectrum of each node in the system in this embodiment is as follows Figure 5 As shown in (a) to (e).

[0087] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An integrated optical polarization multiplexing communication and jamming system with adjustable security level, characterized in that: include: A seed light generating module, configured to equally divide the optical carrier into a first optical carrier and a second optical carrier; a signal modulation module, configured to modulate the radar signal onto a first polarization state of the first optical carrier to obtain a radar modulation signal, modulate the encrypted communication signal onto a second polarization state of the first optical carrier to obtain a communication modulation signal, and combine the two to obtain a modulation signal a; wherein the first polarization state is one of an X polarization state and a Y polarization state, and the second polarization state is the other of the X polarization state and the Y polarization state; The carrier modulation module is used to modulate the Doppler signal on the first polarization state of the second optical carrier to obtain a radar modulated carrier, modulate the up-converted signal on the second polarization state of the second optical carrier to obtain a communication modulated carrier, and combine the two to obtain a modulated carrier b; A security level adjustment module includes an optical combiner, an input optical switch, an optical fiber loop, a polarization controller, and a first control module; the optical combiner is used to combine signals a and b to obtain signal c, and the optical fiber loop includes an optical coupler, an optical amplifier, a delay optical fiber, and a loop optical switch; the first control module is used to control the input optical switch to be turned on to allow signal c to enter the optical coupler; the first control module is also used to control the loop optical switch to be turned on, so that after signal c enters the optical coupler, a portion passes through the optical amplifier, the delay optical fiber, and the loop optical switch and then re-enters the optical coupler for continuous circulation, while the other portion enters the polarization controller for polarization state restoration to obtain the target signal; the delay optical fiber is used to provide a delay for radar distance deception, and the optical amplifier is used to compensate for the loss of the optical coupler and optical fiber, while providing ASE noise to mask the encrypted signal and increase the encryption level of the communication signal; the first control module controls the number of cycles of signal c in the optical fiber loop by controlling the connection time of the input optical switch and the loop optical switch, thereby obtaining different levels of radar signal distance deception and communication signal encryption levels; Among them, the number of cycles N of the signal c in the optical fiber loop and the distance deception amount of the radar signal satisfy the relationship: Δτ is the delay of each optical fiber loop, c is the speed of light in the optical fiber; N and the noise increment of the communication signal satisfy the relationship ΔP N (f) = 2N(G-1)n sp hν,G、n sp are the gain and spontaneous emission coefficient of the optical amplifier, h is the Planck constant, and ν is the photon frequency; The signal processing and transmission module is used to obtain the interference signal d in the electrical domain by beating the radar modulation signal and the radar modulation carrier in the target signal and send it, and to obtain the encrypted communication signal e in the electrical domain by beating the communication modulation signal and the communication modulation carrier in the target signal and send it.

2. The system according to claim 1, wherein The up-converted signal is a single-tone signal, and the expression of the encrypted communication signal e is: I comm. (t)=A comm. (t)exp(j2πf comm. t) Among them, f comm. is the frequency of the single tone signal, that is, the frequency of the communication signal e, A comm. (t) is the amplitude of the encrypted communication signal, j is the imaginary unit; The Doppler signal is a sawtooth wave signal or a high-power single-tone signal; When the Doppler signal is a sawtooth wave, the expression of the interference signal d is: I radar (t)=A radar (t)exp[j2π(f radar -f d )t] Among them, f radar is the center frequency of the radar signal, A radar is the amplitude of the interference signal, f d is the frequency of the single tone signal, i.e. the frequency shift deception of the interference signal d; When the Doppler signal is a high-power single-tone signal, the expression of the interference signal d is: Among them, nf d is the frequency shift deception of the interference signal d, n∈Z.

3. The system according to claim 1, wherein: The optical fiber loop further includes an optical filter, which is placed between the loop optical switch and the delay optical fiber.

4. The system according to claim 1, wherein The signal modulation module includes: a receiving antenna for receiving radar signals; DP-DPMZM, used to split the first optical carrier into first and second polarization states, modulate the radar signal on the first polarization state of the first optical carrier to obtain a radar modulation signal, modulate the encrypted secure communication signal on the second polarization state of the first optical carrier to obtain a communication modulation signal, and combine the two to obtain a modulation signal a; The carrier modulation module includes a DP-DDMZM, which is used to divide the second optical carrier into a first polarization state and a second polarization state, modulate the Doppler signal on the first polarization state of the second optical carrier to obtain a radar modulated carrier, modulate the up-converted signal on the second polarization state of the second optical carrier to obtain a communication modulated carrier, and combine the two to obtain a modulated carrier b.

5. The system according to claim 1, wherein: The signal processing and transmission module includes: an optical polarization beam splitter, configured to split the target signal into a first polarization state and a second polarization state; an interference light detector, configured to obtain an interference signal d in the electrical domain by beating the radar modulated signal in the first polarization state with the radar modulated carrier; An interference transmitting antenna, used for transmitting an interference signal d; a communication optical detector, configured to obtain an encrypted communication signal e in the electrical domain by beating the communication modulated signal in the second polarization state with the communication modulated carrier; The communication transmitting antenna is used to send the encrypted communication signal e.

6. The system according to claim 5, wherein: The signal processing and transmission module also includes a second control module, an interference optical switch and a communication optical switch: The second control module controls the interference light switch to allow the radar modulated signal and the radar modulated carrier to enter the interference light detector at a specified time; The second control module controls the communication optical switch to allow the communication modulation signal and the communication modulation carrier to enter the interference light detector at a specified time.

7. The system according to claim 6, wherein: The signal processing and transmitting module further includes an interference light attenuator arranged between the interference light switch and the interference light detector, and a communication light attenuator arranged between the communication light switch and the communication light detector.

8. The system according to claim 1, wherein: The seed light generating module includes a beam splitter.

9. The system according to claim 8, wherein The seed light generating module further includes a laser.

10. The system according to claim 1, wherein: The encryption method of the communication signal is quantum noise stream encryption or noise-like encryption.

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