A Photonics-Based Compressive Sensing Measurement Method and Device

Abstract

The present invention provides a photonics-based compressive sensing measurement method and apparatus. The method includes: loading a radio frequency signal and a pseudo-random signal onto first and second Mach-Zehnder modulators to obtain first and second optical signals; after the first and second optical signals are orthogonal, combining them into an orthogonal optical signal with first and second polarization states; adjusting the orthogonal optical signal and inputting it to a polarization beam splitter so that the first and second polarization states of the orthogonal optical signal form first, second, third, and fourth angles with the main axes of the first and second output ends of the polarization beam splitter respectively; inputting the first and second optical fields output from the first and second output ends to a balanced photodetector to obtain a photocurrent; and approximately calculating the mixing result of the radio frequency signal and the pseudo-random signal from the photocurrent. The present invention can identify high-frequency signals at a far lower rate than the Nyquist sampling rate with a simple apparatus, without the need to pre-measure the optical link parameters or set special modulation coefficients, is simple and easy to implement, and effectively reduces costs and losses, and can be widely applied to actual systems such as radar and communication.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave photonics, and particularly relates to a photonics-based compressive sensing measurement method and device. Background Art

[0002] In the fields of modern electronic warfare or wireless communication, intercepting microwave signals and accurately identifying their frequencies is of great significance. In practical applications, this kind of identification needs to be realized within a relatively wide frequency range, and at the same time, low cost, low power loss, high accuracy rate, and good real-time performance are required. Traditional means first convert the intercepted signal into a digital signal through an analog-to-digital converter, and then calculate its frequency by fast Fourier transform. According to the Nyquist sampling theorem, to recover the information contained in the original signal, the sampling rate needs to be at least twice the maximum frequency in the frequency components contained in the intercepted signal. In this way, when the sampling rate is very large, the analog-to-digital converter in traditional means has difficulties in storing and real-time processing data.

[0003] When the frequency domain of the intercepted signal satisfies sparsity, the frequency information of the intercepted signal can be recovered by the method of compressive sensing under extremely low sampling rate conditions. Compressive sensing includes a measurement process and a reconstruction process. The measurement process includes multiplying the intercepted radio frequency signal by a pseudo-random sequence (mixing), low-pass filtering (integration), and downsampling; the reconstruction process is to recover the original signal by algorithms such as basis pursuit algorithm and orthogonal matching pursuit. The key point of the entire measurement process lies in the mixing of the intercepted signal and the pseudo-random sequence. When mixing in the electrical domain, the working bandwidth and center frequency are severely restricted. Microwave photonics has advantages such as low loss, good tuning ability, and anti-electromagnetic interference, so many photonics-based compressive sensing schemes have been proposed. However, existing schemes often involve complex system structures, or there are other interference terms generated in addition to multiplying the intercepted radio frequency signal by the pseudo-random sequence, or the parameters of the optical link need to be measured, and these disadvantages limit the application scope of photonics-based compressive sensing schemes. Summary of the Invention

[0004] Based on the above problems, the present invention provides a photonics-based compressive sensing measurement method and device, which can identify high-frequency signals under conditions far lower than the Nyquist sampling rate using a simple device.

[0005] The present invention provides a photonics-based compressive sensing measurement method, including:

[0006] Loading a radio frequency signal onto a first Mach-Zehnder modulator to obtain a first optical signal, and loading a pseudo-random signal onto a second Mach-Zehnder modulator to obtain a second optical signal;

[0007] The first optical signal and the second optical signal are orthogonally combined into an orthogonal optical signal, which has two polarization states, namely the first polarization state and the second polarization state. Among them, the first polarization state is the same as the polarization state of the first optical signal, and the second polarization state is the same as the polarization state of the second optical signal;

[0008] Adjust the orthogonal optical signal and input it into a polarization beam splitter. The polarization beam splitter includes a first output end and a second output end. Among them, the first polarization state of the orthogonal optical signal forms a first angle with the main axis of the first output end, the first polarization state of the orthogonal optical signal forms a second angle with the main axis of the second output end, the second polarization state of the orthogonal optical signal forms a third angle with the main axis of the first output end, and the second polarization state of the orthogonal optical signal forms a fourth angle with the main axis of the second output end;

[0009] Input the first optical field output from the first output end and the second optical field output from the second output end into a balanced photodetector to obtain a photocurrent;

[0010] Perform an approximate calculation on the photocurrent to obtain the mixing result of the radio frequency signal and the pseudo-random signal.

[0011] Further, the method further includes: splitting a linearly polarized optical signal into a first linearly polarized optical signal and a second linearly polarized optical signal, inputting the first linearly polarized optical signal into a first Mach-Zehnder modulator, and inputting the second linearly polarized optical signal into a second Mach-Zehnder modulator.

[0012] Further, the expressions of the first polarization state E x (t) and the second polarization state E y (t) are respectively:

[0013] E x (t) = E 0 exp(j2πf 0 t){exp[jβ 1 cos(2πft) + jπ / 2] + exp[-jβ 1 cos(2πft) - jπ / 2]}

[0014] = -2E 0 exp(j2πf 0 t)sin[β 1 cos(2πft)]

[0015] E y (t) = E 0 exp(j2πf 0 t){exp[jβ 2 r(t) + jπ / 2] + exp[-jβ 2 r(t) - jπ / 2]}

[0016] = -2E 0 exp(j2πft 0 )sin[β 2 r(t)]

[0017] where β 1 = πV 1 / Vπ and β 2 = πV 2 / Vπ are the modulation coefficients corresponding to the RF signal and the pseudo-random signal, Vπ is the half-wave voltage of the first Mach-Zehnder modulator and the second Mach-Zehnder modulator, V 1 、V 2 are the amplitudes of the RF signal and the pseudo-random signal, and r(t) is a pseudo-random sequence consisting of {+1, -1}.

[0018] Furthermore, the first optical field E 1 (t) output from the first output end and the second optical field E 2 (t) output from the second output end satisfy:

[0019]

[0020] Furthermore, the expression of the photocurrent i(t) is:

[0021]

[0022] where E 1 (t) * and E 2 (t) * are the conjugates of the first optical field E 1 (t) and the second optical field E 2 (t), respectively.

[0023] Furthermore, the approximate calculation of the photocurrent to obtain the mixing result of the RF signal and the pseudo-random signal includes:

[0024] i(t) ∝ 16J 1 (β 1 )cos(2πft)sin[β 2 r(t)]

[0025] ≈ 16J 1 (β 1 )cos(2πft)β 2 r(t)

[0026] where J 1 (β 1 ) is the first-order coefficient corresponding to the Bessel expansion.

[0027] Another aspect of the present invention provides a photonics-based compressive sensing measurement device, comprising:

[0028] A first Mach-Zehnder modulator for modulating a radio frequency signal to obtain a first optical signal;

[0029] A second Mach-Zehnder modulator for modulating a pseudo-random signal to obtain a second optical signal;

[0030] A polarization beam combiner for combining the first optical signal and the second optical signal into an orthogonally polarized optical signal;

[0031] A polarization beam splitter for splitting the orthogonally polarized optical signal into two polarization states according to a certain power ratio, and outputting a first optical field and a second optical field;

[0032] A balanced photodetector with two built-in photodetectors for converting the first optical field and the second optical field into photocurrents.

[0033] Further, the device further comprises:

[0034] A laser for generating a linearly polarized optical signal;

[0035] A coupler for splitting the linearly polarized optical signal into a first linearly polarized optical signal and a second linearly polarized optical signal.

[0036] Further, the device further comprises:

[0037] An arbitrary waveform generator for generating a pseudo-random sequence;

[0038] A voltage source for controlling the first Mach-Zehnder modulator and the second Mach-Zehnder modulator to be both at the minimum bias point;

[0039] A polarization controller for adjusting the polarization angle of the orthogonally polarized optical signal.

[0040] Further, the first Mach-Zehnder modulator and the second Mach-Zehnder modulator are connected in a push-pull manner.

[0041] A photonics-based compressive sensing measurement method and device provided by the present invention have the following beneficial effects:

[0042] (1) Only one modulator is used, with a simple structure, which is convenient for integration and application in different fields, and has broad application prospects.

[0043] (2) A simple electro-optical modulation method is used, without the need to set a specific power to meet different modulation coefficients, greatly reducing the operation difficulty.

[0044] (3) The use of a balanced photodetector directly eliminates the DC component, eliminating the need for additional electrical components such as DC blockers, resulting in a compact structure with a good scope of application. Description of the Drawings

[0045] Figure 1 Flowchart of a photonics-based compressive sensing measurement method according to the present invention;

[0046] Figure 2 Schematic diagram of a photonics-based compressive sensing measurement device according to the present invention;

[0047] Figure 3A Time-domain waveform diagram obtained by simulating the intercepted RF signal in an embodiment of the present invention;

[0048] Figure 3B Spectrum diagram obtained by simulating the intercepted RF signal in an embodiment of the present invention;

[0049] Figure 3C Time-domain waveform diagram obtained by simulating the pseudo-random sequence in an embodiment of the present invention on a relatively long time scale;

[0050] Figure 3D Time-domain waveform diagram obtained by simulating the pseudo-random sequence in an embodiment of the present invention on a relatively short time scale;

[0051] Figure 4A Time-domain waveform diagram obtained by simulating the intercepted RF signal after passing through the random mixing module in an embodiment of the present invention;

[0052] Figure 4B Time-domain waveform diagram obtained by simulating after passing through the low-pass filter module in an embodiment of the present invention;

[0053] Figure 4C Time-domain waveform diagram obtained by simulating after passing through the downsampling module in an embodiment of the present invention;

[0054] Figure 5A Time-domain waveform diagram of the recovered signal obtained by simulating through the orthogonal matching pursuit method in an embodiment of the present invention;

[0055] Figure 5B Spectrum diagram of the recovered signal obtained by simulating through the fast Fourier transform in an embodiment of the present invention.

[0056] In the figure:

[0057] 1 - Polarization - multiplexed Mach - Zehnder modulator; 101 - Coupler; 102 - First Mach - Zehnder modulator; 103 - Second Mach - Zehnder modulator; 104 - Polarization rotator; 105 - Polarization beam combiner; 2 - Random mixing module; 201 - Laser; 202 - Arbitrary waveform generator; 203 - Voltage source; 204 - Polarization controller; 205 - Polarization beam splitter; 206 - Balanced photodetector; 3 - Low - pass filtering module; 4 - Downsampling module. Detailed implementation manners

[0058] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. Additionally, it should be noted that for the sake of description, only parts related to the present application are shown in the drawings, rather than all the content. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations can be implemented in parallel, concurrently or simultaneously. In addition, the order of the operations can be rearranged. When the operations are completed, the process can be terminated, but there may also be additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, sub - program, etc.

[0059] The present invention provides a photonics - based compressive sensing measurement method and device, which can identify high - frequency signals using a simple device under conditions far lower than the Nyquist sampling rate.

[0060] As Figure 1 shown is a flowchart of a photonics - based compressive sensing measurement method of the present invention. It includes:

[0061] S101, loading a radio - frequency signal and a pseudo - random signal onto the first and second Mach - Zehnder modulators to obtain first and second optical signals;

[0062] S102, orthogonally combining the first and second optical signals into an orthogonally polarized optical signal with first and second polarization states;

[0063] S103, adjusting the orthogonally polarized optical signal and inputting it into a polarization beam splitter, such that the first and second polarization states of the orthogonally polarized optical signal form first, second, third, and fourth angles with the main axes of the first and second output ends of the polarization beam splitter respectively;

[0064] S104, inputting the first and second optical fields output from the first and second output ends into a balanced photodetector to obtain a photocurrent;

[0065] S105. Approximately calculate the photocurrent to obtain the mixing result of the radio frequency signal and the pseudo-random signal.

[0066] Figure 2 A photonics-based compressive sensing measurement device of the present invention.

[0067] An embodiment of the present invention specifically includes the following steps:

[0068] The linearly polarized optical signal generated by the laser 201 is expressed as E 0 exp(j2πf 0 t), where E 0 and f 0 are the amplitude and frequency of the optical carrier respectively, t represents time, and j represents the imaginary unit. The optical field in this linearly polarized state is divided into a first linearly polarized optical signal and a second linearly polarized optical signal through the coupler 101. The first linearly polarized optical signal is input into the first Mach-Zehnder modulator 102, and the second linearly polarized optical signal is input into the second Mach-Zehnder modulator 103.

[0069] According to the frequency f and amplitude V 1 of the intercepted radio frequency signal, it is expressed as V 1 cos(2πft). As shown in Figure 3A and 3B , the time-domain waveform diagram and frequency spectrum diagram obtained by simulating the intercepted radio frequency signal are respectively shown. It is loaded onto the first Mach-Zehnder modulator 102 in the polarization multiplexing Mach-Zehnder modulator 1 as the radio frequency signal through the radio frequency input port.

[0070] Use an arbitrary waveform generator 202 to generate a pseudo-random sequence V 2 r(t). As shown in Figure 3C and 3D , the time-domain waveform diagrams of the pseudo-random sequence on a longer time scale and a shorter time scale are respectively shown. It is loaded onto the second Mach-Zehnder modulator 103 in the polarization multiplexing Mach-Zehnder modulator 1 as the pseudo-random signal through the radio frequency input port.

[0071] Both the first Mach-Zehnder modulator 102 and the second Mach-Zehnder modulator 103 include a radio frequency input port and two bias voltage input ports. Connect the positive and negative electrodes of the voltage source 203 to the two bias voltage input ports of each of them respectively. Adjust the voltage source 203 so that the voltage between the two bias voltage input ports of each of them is π, so that both the first Mach-Zehnder modulator 102 and the second Mach-Zehnder modulator are at the minimum bias point.

[0072] The first optical signal output from the output end of the first Mach-Zehnder modulator 102 is input into the polarization beam combiner 105, and the second optical signal output from the output end of the second Mach-Zehnder modulator 103 passes through the polarization rotator 104 so that the second optical signal is orthogonal to the first optical signal and is input into the polarization beam combiner 105. After passing through the polarization beam combiner 105, the orthogonal first optical signal and the second optical signal are combined into an orthogonal optical signal. The orthogonal optical signal has two polarization states, namely the first polarization state and the second polarization state, where the first polarization state is the same as the polarization state of the first optical signal, and the second polarization state is the same as the polarization state of the second optical signal.

[0073] The first polarization state E x (t) and the second polarization state E y (t) are respectively expressed as:

[0074] E x (t) = E 0 exp(j2πf 0 t){exp[jβ 1 cos(2πft) + jπ / 2] + exp[-jβ 1 cos(2πft) - jπ / 2]}

[0075] = -2E 0 exp(j2πf 0 t)sin[β 1 cos(2πft)]

[0076] E y (t) = E 0 exp(j2πf 0 t){exp[jβ 2 r(t) + jπ / 2] + exp[-jβ 2 r(t) - jπ / 2]}

[0077] = -2E 0 exp(j2πf 0 t)sin[β 2 r(t)]

[0078] Where β 1 = πV 1 / Vπ and β 2 = πV 2 / Vπ are the modulation coefficients corresponding to the radio frequency signal and the pseudo-random signal, Vπ is the half-wave voltage of the first Mach-Zehnder modulator 102 and the second Mach-Zehnder modulator 103, V 1 、V 2 are the amplitudes of the radio frequency signal and the pseudo-random signal, and r(t) is a pseudo-random sequence composed of {+1, -1}.

[0079] Following the polarization multiplexed Mach-Zehnder modulator 1 are a polarization controller 204 and a polarization beam splitter 205. The above-mentioned orthogonal optical signals are input into the polarization controller 204 and the polarization beam splitter 205. The polarization controller 204 is rotated so that the first polarization state of the orthogonal optical signal forms an angle of 45° with the main axis of the first output end of the polarization beam splitter 205 and an angle of 45° with the main axis of the second output end, and the second polarization state of the orthogonal optical signal forms an angle of 45° with the main axis of the first output end of the polarization beam splitter 205 and an angle of 135° with the main axis of the second output end. Then, the first optical field E 1 (t) output from the first output end of the polarization beam splitter 205 and the second optical field E 2 (t) output from the second output end satisfy:

[0080]

[0081] The first optical field and the second optical field are input into a balanced photodetector 206. The balanced photodetector 206 has two built-in photodetectors, which convert the optical signal into an electrical signal to obtain a photocurrent. The expression of the photocurrent:

[0082]

[0083] where E 1 (t) * and E 2 (t) * are the conjugates of the first optical field E 1 (t) and the second optical field E 2 (t), respectively.

[0084] Then, an approximate calculation is performed on the photocurrent: Under the condition of small-signal modulation, only the first term of the Bessel expansion is considered. Additionally, it is assumed that r(t) is very small, and sin(β 2 r(t)) is approximately equal to β 2 r(t). Then, the above formula can be expressed as:

[0085] i(t) ∝ 16J 1 (β 1 ) cos(2πft) sin[β 2 r(t)]

[0086] ≈ 16J 1 (β 1 ) cos(2πft) β 2 r(t)

[0087] where J 1 (β 1 ) is the corresponding first-order coefficient after applying the Bessel expansion.

[0088] So far, we have obtained the mixing result of the radio frequency signal and the pseudo-random signal as shown in the above formula, without any other interference terms. The simulation result is as Figure 4A shown.

[0089] Integrate the mixed signal through a low-pass filtering module to filter out high-frequency components:

[0090] Set the length of the low-pass filtering module to P (P = N / M), and set its shape to rectangular or Gaussian. The low-pass filtering module is represented as h(n), where n = 1, 2,..., P. Then the matrix H can be represented as:

[0091]

[0092] The simulation result is as Figure 4B shown.

[0093] Pass the above analog signal through a downsampling module, and keep one sampling point out of every P sampling points of the obtained digital signal. The specific process is represented as:

[0094] D ij = δ(i - j / M), where i = 1...M and j = 1...N

[0095] The simulation result is as Figure 4C shown.

[0096] So far, the observation process included in compressive sensing has been completed. The reconstruction process of compressive sensing mainly relies on various algorithms, such as basis pursuit matching, orthogonal matching pursuit, etc.

[0097] Figure 5A shows the time-domain waveform diagram of the recovered signal obtained after using the orthogonal matching pursuit algorithm; Figure 5B is the spectrogram obtained through fast Fourier transform.

[0098] The present invention provides a compressive sensing measurement device based on photonics. According to the above-mentioned compressive sensing measurement method based on photonics, the identification of high-frequency signals can be achieved under the condition far lower than the Nyquist sampling rate.

[0099] A compressive sensing measurement device based on photonics according to an embodiment of the present invention includes a random mixing module 2, a low-pass filtering module 3, and a downsampling module 4. The random mixing module 2 is used to multiply the input signal by a pseudo-random sequence; the low-pass filtering module 3 is used to filter out high-order frequency components; the downsampling module 4 is used to convert an analog signal into a digital signal under the condition that the sampling rate is far lower than the Nyquist sampling rate.

[0100] The above-mentioned random mixing module 2 includes: a laser 201 for generating a linearly polarized optical signal; a coupler 101 for splitting the linearly polarized optical signal into a first linearly polarized optical signal and a second linearly polarized optical signal; a polarization multiplexing Mach-Zehnder modulator 1 for realizing electro-optical modulation of a radio frequency signal and a pseudo-random signal on two polarization states respectively; an arbitrary waveform generator 202 for generating a pseudo-random sequence; a voltage source 203 for controlling a first Mach-Zehnder modulator 102 and a second Mach-Zehnder modulator 103 to make them both at the minimum bias point; a polarization controller 204 for adjusting the polarization angle of the orthogonal optical signal; a polarization beam splitter 205 for splitting the orthogonal optical signal into two polarization states according to a certain power ratio and outputting a first optical field and a second optical field; a balanced photodetector 206 with two built-in photodetectors for converting the first optical field and the second optical field into photocurrents, that is, the electrical signals obtained by the two photodetectors can be directly subtracted to obtain the photocurrent.

[0101] The above-mentioned polarization multiplexing Mach-Zehnder modulator 1 includes: a coupler 101; a first Mach-Zehnder modulator 102; a second Mach-Zehnder modulator 103; a polarization rotator 104; a polarization beam combiner 105; wherein,

[0102] The coupler 101 is used for splitting the linearly polarized optical signal into a first linearly polarized optical signal and a second linearly polarized optical signal; the first Mach-Zehnder modulator 102 is used for modulating a radio frequency signal to obtain a first optical signal; the second Mach-Zehnder modulator 103 is used for modulating a pseudo-random signal to obtain a second optical signal; the polarization rotator 104 is used for rotating the polarization state of the second optical signal output from the output end of the second Mach-Zehnder modulator 103 by 90° to make it orthogonal to the first optical signal; the polarization beam combiner 105 is used for combining the first optical signal and the second optical signal into an orthogonal optical signal.

[0103] In this embodiment, both the first Mach-Zehnder modulator 102 and the second Mach-Zehnder modulator 103 include a radio frequency input port and two bias voltage input ports, and both have upper and lower branch arms. The first Mach-Zehnder modulator 102 and the second Mach-Zehnder modulator 103 are connected in a push-pull manner, and the modulation coefficients between the two branch arms are opposite.

[0104] A photonics-based compressive sensing measurement method and device provided by the present invention have the following beneficial effects:

[0105] (1) Only one modulator is used, the structure is simple, it is convenient to integrate and apply to different fields, and it has broad application prospects.

[0106] Miniaturization and low power consumption are the inevitable trends in the development of microwave photonics. Therefore, it is very meaningful to meet the integration requirements while realizing the original functions. The link of the present invention is simple and does not involve large devices such as long-distance optical fibers, wide-spectrum light sources, and spectral filters, which has a higher possibility for integration. Although some existing technical solutions do not involve the above-mentioned large devices, they often use two or more discrete modulators, which increases the difficulty of component integration. The polarization multiplexing Mach-Zehnder modulator used in this solution is composed of two modulators, but the overall is already an integrated component, which is equivalent to a modulator, with a simple structure, easy to integrate and apply to different fields, and has broad application prospects.

[0107] (2) Using a simple optoelectronic modulation method, there is no need to set a specific power to meet different modulation coefficients, which greatly reduces the operation difficulty.

[0108] When the existing optical mixing scheme involves a modulator to complete the measurement purpose, it is necessary to adjust the power of the incident RF signal to be measured to a special value to meet the required specific conditions, which is very limited in practical applications. Because in practical applications, there are generally real-time requirements. For example, in electronic warfare and communication, after the receiver receives the signal, it is necessary to measure the frequency information of this signal in a very short time. If a specific power value is required for subsequent measurements, a power detection feedback system may need to be introduced, which will lead to a complex system and also greatly increase the time, limiting the practicality.

[0109] (3) The use of a balanced photodetector directly eliminates the DC component, without the need to add additional electrical devices such as DC blockers, with a compact structure and good applicability.

[0110] Generally, the photocurrent output by the photodetector contains a DC component. If you want to remove this DC component, the conventional solution is to add a DC blocker at the output of the photodetector to filter out the DC component, or use an AC-coupled photodetector. The balanced photodetector used in the technical solution of the present invention has two small photodetectors inside. After the currents output by these two small detectors are subtracted, it is used as the total output. In this way, through ingenious design, the output current can be made to not contain a DC component. In addition, some solutions are to eliminate interference terms such as DC by pre-measuring the link parameters, which brings many inconveniences to practical applications.

[0111] In summary, the present invention provides a photonics-based compressive sensing measurement method and apparatus, which can identify high-frequency signals using a simple device under conditions far below the Nyquist sampling rate. The advantages of the present invention are simple structure, no need to set specific power to meet different modulation coefficients, no need to pre-measure the parameters of the optical link, no interference terms except the desired product term after mixing, and have many advantages such as low cost, low power consumption, and good applicability, and can be applied to electronic warfare or communication systems.

[0112] The specific embodiments described above have further elaborated on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A photonics-based compressive sensing measurement method, characterized in that, it includes: Loading a radio frequency signal onto a first Mach-Zehnder modulator to obtain a first optical signal, and loading a pseudo-random signal onto a second Mach-Zehnder modulator to obtain a second optical signal; Orthogonally combining the first optical signal and the second optical signal to form an orthogonal optical signal, the orthogonal optical signal having two polarization states, namely a first polarization state and a second polarization state, wherein the first polarization state is the same as the polarization state of the first optical signal, and the second polarization state is the same as the polarization state of the second optical signal; Adjusting the orthogonal optical signal and inputting it into a polarization beam splitter, the polarization beam splitter including a first output end and a second output end, wherein the first polarization state of the orthogonal optical signal forms a first angle with the main axis of the first output end, the first polarization state of the orthogonal optical signal forms a second angle with the main axis of the second output end, the second polarization state of the orthogonal optical signal forms a third angle with the main axis of the first output end, and the second polarization state of the orthogonal optical signal forms a fourth angle with the main axis of the second output end; Inputting the first optical field output from the first output end and the second optical field output from the second output end into a balanced photodetector to obtain a photocurrent; Performing approximate calculation on the photocurrent to obtain the mixing result of the radio frequency signal and the pseudo-random signal; The first polarization state of the orthogonal optical signal and the second polarization state are respectively expressed as follows: where β 1 = πV 1 / Vπ and β 2 = πV 2 / Vπ are the modulation coefficients corresponding to the RF signal and the pseudo-random signal, Vπ is the half-wave voltage of the first Mach-Zehnder modulator and the second Mach-Zehnder modulator, V 1 、V 2 are the amplitudes of the RF signal and the pseudo-random signal, r(t) is a pseudo-random sequence composed of {+1, -1}; Dividing a linearly polarized optical signal into a first linearly polarized optical signal and a second linearly polarized optical signal, the first linearly polarized optical signal being input into a first Mach-Zehnder modulator, and the second linearly polarized optical signal being input into a second Mach-Zehnder modulator.

2. The method according to claim 1, characterized in that, The first optical field output from the first output end and the second optical field output from the second output end satisfy: 。 3. The method according to claim 1, characterized in that, The photocurrent is expressed as: Among them, and are respectively the conjugates of the first optical field and the second optical field .

4. The method according to claim 1, characterized in that, The performing approximate calculation on the photocurrent to obtain the mixing result of the radio frequency signal and the pseudo-random signal includes: wherein is the first-order coefficient corresponding to the application of the Bessel expansion.

5. A photonics-based compressive sensing measurement device for performing the photonics-based compressive sensing measurement method according to any one of claims 1-4 above, characterized in that, it includes: A first Mach-Zehnder modulator for modulating a radio frequency signal to obtain a first optical signal; A second Mach-Zehnder modulator for modulating a pseudo-random signal to obtain a second optical signal; A polarization beam combiner for combining the first optical signal and the second optical signal into an orthogonal optical signal; A polarization beam splitter for splitting the orthogonal optical signal into two polarization states according to a certain power ratio and outputting a first optical field and a second optical field; A balanced photodetector with two built-in photodetectors for converting the first optical field and the second optical field into a photocurrent; The device further includes: A laser for generating a linearly polarized optical signal; A coupler for splitting the linearly polarized optical signal into a first linearly polarized optical signal and a second linearly polarized optical signal; The device further includes: An arbitrary waveform generator for generating a pseudo-random sequence; A voltage source for controlling the first Mach-Zehnder modulator and the second Mach-Zehnder modulator to both be at the minimum bias point; A polarization controller for adjusting the polarization angle of the orthogonal optical signal.

6. The device according to claim 5, characterized in that, The first Mach-Zehnder modulator and the second Mach-Zehnder modulator are connected in a push-pull manner.

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