A microwave photonics system dual optical path cancellation optical noise elimination method and device

Abstract

The application discloses a microwave photonics system double optical path cancellation optical noise elimination method and device. The method comprises the following steps: receiving a pulse light source signal, and inputting the pulse light source signal into a pre-constructed double optical path; collecting an output signal of the double optical path, and constructing the collected output signal of the double optical path into virtual double-channel data; determining a down-conversion signal from the virtual double-channel data by using a Fast-ICA algorithm, so as to realize elimination of an optical noise signal. The above scheme realizes elimination of optical relative intensity noise in a microwave photonics system, has fast calculation speed, can recover the down-conversion signal to the maximum extent, and improves the sensitivity of the system; and the above method does not need strict consistency of amplitudes and phases of double optical path signals, and the phases of the double optical path signals can be different by an integral multiple of a heavy frequency period, so that the method is more easily realized in engineering.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave photonics optical noise cancellation, and particularly relates to a microwave photonics system double optical path cancellation optical noise cancellation method and device. BACKGROUND

[0002] With the rapid development of civil and military radio technology, the frequency bands occupied by electromagnetic signals in space are more and more, and the working bandwidth of signals is wider and wider. New systems of electromagnetic signals such as wideband frequency modulation, time-space burst, etc. pose new challenges to electromagnetic spectrum sensing. The traditional electromagnetic spectrum sensing system uses multiple groups of antennas with different receiving frequency bands to receive electromagnetic signals. The receivers of the system usually use the sweep frequency method, which may lose the transient signals in the unscanned frequency band and cannot realize continuous and seamless capture and analysis of signals.

[0003] The development of optical down-conversion electric field measurement technology opens up a new way for the design of electromagnetic spectrum sensing systems. This technology can down-convert all signals in a wide frequency range to a single frequency range for reception, so that the signal acquisition is no longer limited by the bandwidth and sweep speed of the receiver. It can quickly obtain all signals to be measured in the wide frequency range, and has the advantages of small size, light weight, low power consumption, and low requirements for hardware performance. However, due to the influence of the relative intensity noise (RIN) of the light source, a large amplitude noise spectrum peak is generated in the low frequency range. The noise spectrum peak will block or drown the signal spectrum down-converted to this region, resulting in a decrease in the sensitivity of the system.

[0004] The existing methods for suppressing the relative intensity noise of the light source mainly include noise suppression at the light source, circuit noise subtraction, optical path noise subtraction, etc. The existing technology at least has the following problems:

[0005] The noise suppression method at the light source reduces the relative intensity noise by increasing the spectral width of the light source. However, when the spectral width is too large, it will affect the stability of the output center wavelength and the output spectrum of the light source.

[0006] The circuit noise subtraction method removes the RIN by subtracting the two beams of light after converting the optical signal into an electrical signal based on the principle that the RIN characteristics and distribution of the two beams of light are consistent. However, the phase, amplitude and polarization state of the two beams of light need to be highly consistent, otherwise the RIN cannot be eliminated.

[0007] The optical path noise subtraction method eliminates the noise of the light source by constructing a differential structure and using a differential optical probe to complete the elimination of the RIN noise. However, this method requires the design of a differential optical modulator, and the phase alignment of the optical path also needs to be completed at the differential optical probe, which has a high cost. SUMMARY

[0008] In view of the above problems, the present application is proposed to provide a microwave photonics system dual optical path cancellation optical noise elimination method and device to overcome the above problems or at least partially solve the above problems.

[0009] According to an aspect of the present application, there is provided a microwave photonics system dual optical path cancellation optical noise elimination method, comprising:

[0010] receiving a pulsed light source signal and inputting the pulsed light source signal into a pre-constructed dual optical path;

[0011] collecting an output signal of the dual optical path and constructing the collected output signal of the dual optical path into virtual dual-channel data;

[0012] determining a down-converted signal from the virtual dual-channel data by using a Fast-ICA algorithm, thereby realizing elimination of an optical noise signal.

[0013] In some embodiments, the pre-constructed dual optical path comprises an optical coupler and a first optical path and a second optical path connected to the optical coupler, the first optical path comprising an optical electric field probe, an optical-electric converter and a low-pass filter connected in series by optical fibers, and the second optical path comprising an optical-electric converter and a low-pass filter connected in series by optical fibers;

[0014] collecting an output signal of the dual optical path and constructing the collected output signal of the dual optical path into virtual dual-channel data comprises:

[0015] the output signal collected from the first optical path is:

[0016] S CHA_out (n)=A1*V 光噪声 (n)+B1*V 下变频信号 (n)

[0017] the output signal collected from the second optical path is:

[0018] S CHB_out (n)=A2*V 光噪声 (n)

[0019] the constructed virtual dual-channel data is:

[0020]

[0021] wherein A1, A2 and B1 are parameters determined according to the dual optical path, m represents a discrete data point of the first optical path signal, n represents a discrete data point of the second optical path signal, V 光噪声 is an optical noise signal, and V 下变频信号 is a down-converted signal.

[0022] In some embodiments, before the collected output signals of the dual optical paths are configured into virtual dual-channel data, the method further comprises:

[0023] Periodically aligning or phase aligning the dual optical paths.

[0024] In some embodiments, periodically aligning the dual optical paths comprises:

[0025] Since the dual optical path signals S CHA (m) and S CHB (n) are mutually independent, the cross-correlation of the dual optical path signals is: 光噪声 下变频信号 加性白噪声

[0026] R CHA，CHB = E{S CHA (m)*S CHB (n)}

[0027] ≈ E{A1*V 光噪声 (m)*A2*V 光噪声 (n)}

[0028] = A1*A2*R 光噪声 (m-n)

[0029] wherein R CHA，CHB represents the cross-correlation of the first optical path output signal and the second optical path output signal, E represents expectation, S CHA (m) represents the first optical path output signal before periodic alignment, S CHB (n) represents the second optical path output signal before periodic alignment, m represents the discrete data point of the first optical path signal, n represents the discrete data point of the second optical path signal, and R 光噪声 represents the autocorrelation of the optical noise.

[0030] As can be seen from the above formula, the cross-correlation of the dual optical path signals mainly represents the autocorrelation of the optical noise of the two paths, and the maximum value appears at the position when the optical noise in the two signals comes from the same pulse period. Therefore, the periodic alignment of the dual optical path signals can be completed by shifting the signal according to the distance of the maximum value point of the cross-correlation envelope from the center line.

[0031] In some embodiments, phase aligning the dual optical paths comprises:

[0032] Adjusting the length of the optical fiber in the second optical path, and realizing the phase alignment of the pulse period according to the display of the oscilloscope.

[0033] ​​​In some embodiments, determining the down-converted signal from the virtual dual-channel data by using the Fast-ICA algorithm to achieve the elimination of the optical noise signal comprises:

[0034] According to the expression of the virtual dual-channel data A1, B1 and V are obtained by using the Fast-ICA algorithm 光噪声 (n) and V 下变频信号 (n);

[0035] According to V TRUE光噪声 =A1*V 光噪声 , V TRUE下变频信号 =B1*V 下变频信号 , the recovery of the real amplitude of the separated signal is completed;

[0036] wherein, V TRUE光噪声 represents the real optical noise signal after the recovery of the amplitude, and V TRUE下变频信号 represents the real down-converted signal after the recovery of the amplitude.

[0037] In some embodiments, determining the down-converted signal from the virtual dual-channel data by using the Fast-ICA algorithm further comprises:

[0038] calculating the cross-correlation coefficient of the separated signal V TRUE光噪声 , V TRUE下变频信号 and the second optical path reference signal after the alignment of the time sequence;

[0039] If the cross-correlation coefficient is less than a preset threshold, the separated signal is considered to be the signal after the elimination of the optical noise and is output; otherwise, it is considered to be the optical noise signal.

[0040] According to another aspect of the present application, a dual optical path cancellation optical noise elimination device of a microwave photonics system is provided, which comprises:

[0041] An input module is adapted to receive a pulsed light source signal and input the pulsed light source signal into a pre-constructed dual optical path.

[0042] A construction module is adapted to collect the output signal of the dual optical path and construct the collected output signal of the dual optical path into virtual dual-channel data.

[0043] A determination module is adapted to determine the down-converted signal from the virtual dual-channel data by using the Fast-ICA algorithm to achieve the elimination of the optical noise signal.

[0044] According to still another aspect of the present application, an electronic device is provided, which comprises a processor, a memory, a communication interface and a communication bus, the processor, the memory and the communication interface complete the communication among each other through the communication bus.

[0045] The memory is configured to store at least one executable instruction, and the executable instruction is configured to enable the processor to perform the operation corresponding to the optical noise cancellation method.

[0046] According to another aspect of the present application, a computer readable storage medium is provided, and the storage medium stores at least one executable instruction, and the executable instruction is configured to enable the processor to perform the operation corresponding to the optical noise cancellation method.

[0047] According to the microwave photonics system double optical path cancellation optical noise cancellation method, the optical relative intensity noise in the microwave photonics system is cancelled, the calculation speed is fast, the down-converted signal can be recovered to the maximum extent, and the sensitivity of the system is improved; and the above method does not require strict consistency of the amplitudes and phases of the double optical path signals, and the phases of the double optical path signals can differ by an integer multiple of the frequency period, and the method is easier to implement in engineering.

[0048] The above description is only a summary of the technical scheme of the present application, in order to enable the technical means of the present application to be more clearly understood and implemented according to the content of the specification, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0049] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present application. Moreover, the same reference numerals in the attached drawings indicate the same or similar components. In the drawings:

[0050] Figure 1 A flow chart of the microwave photonics system double optical path cancellation optical noise cancellation method provided by an embodiment of the present application is shown;

[0051] Figure 2 A structural schematic diagram of the double optical path provided by an embodiment of the present application is shown;

[0052] Figure 3 A structural schematic diagram of the double optical path phase alignment provided by an embodiment of the present application is shown;

[0053] Figure 4 A flow chart of the optical noise cancellation in the double optical path provided by an embodiment of the present application is shown;

[0054] Figure 5 A comparison diagram of the signal spectrum envelope after the optical noise is cancelled and the signal spectrum envelope before the optical noise is cancelled provided by an embodiment of the present application is shown;

[0055] Figure 6A structural schematic diagram of a dual optical path cancellation optical noise elimination device of a microwave photonics system is shown.

[0056] Figure 7 A structural schematic diagram of an electronic device is shown. DETAILED DESCRIPTION

[0057] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0058] The following terms are explained as follows:

[0059] Radio technology: Radio technology is not limited by time and space in propagation, uses radio waves as the main medium, and uses frequency to realize transmission and reception between signals. Current radio technology has become a very important part of daily life, and has been widely used in many fields and has achieved good results, fully embodying the importance of radio technology application in modern society.

[0060] Fast-ICA: Independent component analysis (ICA) is a very effective data analysis tool proposed in recent years, which is mainly used to extract original independent signals from mixed data, and is widely concerned as an effective method of signal separation. Fast ICA algorithm (Fast ICA) is based on fixed-point recursive algorithm, which is suitable for any type of data, and its existence makes it possible to analyze high-dimensional data using ICA. This algorithm is a fast optimization iterative algorithm, which is different from ordinary neural network algorithm. This algorithm uses batch processing, that is, a large number of sample data are involved in the calculation in each iteration. However, from the perspective of distributed parallel processing, this algorithm can still be called a neural network algorithm. Fast-ICA algorithm has forms based on fourth-order cumulant, likelihood maximum, and negative entropy maximum. In addition, the algorithm uses fixed-point iterative optimization algorithm, which makes the convergence more rapid and robust.

[0061] Optical frequency comb: Optical frequency comb (OFC) refers to an optical spectrum composed of a series of uniformly spaced frequency components with coherent stable phase relationship in the frequency spectrum. With the rapid development of optical communication technology, OFC has attracted more and more attention due to its wide application in the fields of optical arbitrary waveform generation, multi-wavelength ultrashort pulse generation, and dense wavelength division multiplexing.

[0062] Down conversion: in the receiver, if the intermediate frequency signal obtained after mixing is lower than the original signal, this kind of mixing method is called down conversion. The purpose of down conversion is to reduce the carrier frequency of the signal or directly remove the carrier frequency to obtain the baseband signal.

[0063] Pulse repetition frequency: the full name is pulse repetition frequency, and the English abbreviation is PRF. It is a concept of pulse radar. The pulse radar transmits pulse modulated signals, and the PRF refers to the number of pulse modulated signals transmitted by the radar transmitter per second.

[0064] Additive white Gaussian noise: (AWGN) is a mathematical model used to simulate the channel between the transmitter and the receiver. This model is a linearly increasing wideband noise with constant spectral density and Gaussian distributed amplitude.

[0065] As shown in Figure 1 The microwave photonics system double optical path cancellation optical noise elimination method comprises the following steps:

[0066] Step 110, receiving a pulsed light source signal, and inputting the pulsed light source signal into a pre-constructed double optical path;

[0067] Step 120, collecting the output signal of the double optical path, and constructing the collected output signal of the double optical path into virtual double-channel data;

[0068] Step 130, determining a down conversion signal from the virtual double-channel data by using a Fast-ICA algorithm, so as to realize elimination of the optical noise signal.

[0069] In summary, the embodiment of the present application provides a microwave photonics system double optical path cancellation optical noise elimination method, which firstly obtains double-channel data by constructing a double optical path, then performs Fast-ICA fast independent component analysis on the obtained double-channel data, and further obtains the main frequency information such as the real down conversion signal.

[0070] In some embodiments, referring to the optical path structure shown in Figure 2 To construct virtual double channels, the original optical down conversion system is improved: a 1:1 power divider is used to divide the femtosecond pulsed light source into two paths, one path of light directly enters the optical probe; the other path of light enters the optical probe after passing through the optical electric field sensor. The electrical signals output by the two optical probes are collected by two channels of the same low-speed acquisition card through the same low-pass filter set.

[0071] In an optional embodiment, the pre-constructed double optical path comprises an optical coupler and a first optical path and a second optical path connected to the optical coupler, the first optical path comprises an optical electric field probe, an optical-electric converter and a low-pass filter connected in series by optical fibers, and the second optical path comprises an optical-electric converter and a low-pass filter connected in series by optical fibers.

[0072] collecting the output signals of the double optical paths, and constructing the collected output signals of the double optical paths as virtual double-channel data comprises:

[0073] The output signal collected from the first optical path is:

[0074] S CHA_out (n) = A1*V 光噪声 (n) + B1*V 下变频信号 (n)

[0075] The output signal collected from the second optical path is:

[0076] S CHB_out (n) = A2*V 光噪声 (n)

[0077] According to the signal modulation principle of the optical down-conversion system, when there is an electromagnetic signal in space, the signal output by the acquisition card is a linear combination of optical noise and a down-converted electromagnetic signal; when there is no electromagnetic signal in space, only optical noise exists in the discrete signal output. Therefore, the virtual double-channel data constructed is:

[0078]

[0079] wherein A1, A2 and B1 are parameters determined according to the double optical paths, m represents a discrete data point of the first optical path signal, n represents a discrete data point of the second optical path signal, V 光噪声 is an optical noise signal, and V 下变频信号 is a down-converted signal.

[0080] In some embodiments, V 光噪声 (n) exists in the two output signals of the acquisition card, but V CHA_out (n1) and V CHB_out (n2) exist with a time delay in time sequence because the lengths of the two optical fibers are different. The Fast-ICA algorithm is sensitive to the selection of initial values, and in order to improve the separation accuracy of the algorithm, the two optical paths also need to be time-aligned.

[0081] Specifically, before collecting the output signals of the double optical paths and constructing the collected output signals of the double optical paths as virtual double-channel data, the double optical paths are periodically aligned or phase-aligned. In the above alignment, the phases can differ by an integer number of the repetition frequency period, and the amplitude consistency of the two optical paths is not required.

[0082] Specifically, in some embodiments, periodically aligning the double optical paths comprises:

[0083] Because the double optical path signals S CHA (m) and S CHBV in (n) 光噪声 , V 下变频信号 and Awgn 加性白噪声 are mutually independent, so the cross-correlation operation of the two optical signals can be obtained as follows:

[0084] R CHA，CHB = E{S CHA (m)*S CHB (n)}

[0085] ≈ E{A1*V 光噪声 (m)*A2*V 光噪声 (n)}

[0086] = A1*A2*R 光噪声 (m-n)

[0087] From the above formula, the cross-correlation of the two optical signals is mainly the autocorrelation of the two optical noises, and the maximum value appears when the optical noises in the two signals come from the same pulse period. Therefore, the period alignment of the two optical signals can be completed by shifting the signal according to the distance of the maximum value point of the cross-correlation envelope from the center line.

[0088] In some embodiments, the phase alignment of the two optical paths includes:

[0089] Adjusting the length of the optical fiber in the second optical path, and achieving the phase alignment of the pulse period according to the display of the oscilloscope, wherein the phase alignment optical path is shown in Figure 3 .

[0090] In some embodiments, the elimination of the optical noise signal is achieved by determining the down-converted signal from the virtual double-channel data using the Fast-ICA algorithm, which includes:

[0091] According to the expression of the virtual double-channel data , the parameters A1 and B1 are obtained using the Fast-ICA algorithm. Specifically, a large amount of virtual double-channel data can be obtained according to the experiment, and the down-converted signal and the optical noise signal can be determined according to the Fast-ICA algorithm. The specific process can refer to the general execution process of the Fast-ICA algorithm, which will not be described here.

[0092] According to V TRUE光噪声 = A1*V 光噪声 , V TRUE下变频信号 = B1*V 下变频信号 , the recovery of the true amplitude of the separated signal is completed.

[0093] In some embodiments, the determination of the down-converted signal from the virtual double-channel data using the Fast-ICA algorithm further includes:

[0094] computing the separated signal V TRUE光噪声 , V TRUE下变频信号 the cross-correlation coefficient of the second optical path reference signal after alignment with the time sequence;

[0095] If the cross-correlation coefficient is less than a preset threshold, the separated signal is considered as a signal after eliminating the optical noise and is output; otherwise, it is considered as an optical noise signal.

[0096] Figure 4 A detailed embodiment is shown as an example. As shown in the figure, the elimination method of this embodiment includes the following steps:

[0097] Step 401, a computer acquires an optical path 1 signal and an optical path 2 reference signal from a collection card.

[0098] The optical path 1 signal is a mixed signal of an optical frequency comb down-converted spatial electromagnetic signal and an optical noise signal; the optical path 2 reference signal is a signal containing only optical noise. The optical noise signals in the two signals are correlated, and the optical noise signal and the optical frequency comb down-converted spatial electromagnetic signal are not correlated.

[0099] Step 402, cross-correlation operation is performed on the two signals, and the maximum position of the cross-correlation complex envelope deviates from the midpoint of the cross-correlation sequence length by a deviation point number. The time delay operation is performed on the two signals by the deviation point number, and the time sequence alignment of the two signals is completed.

[0100] Step 403, a virtual double channel is constructed using the two signals after time sequence alignment, and Fast-ICA algorithm is used to complete the separation of the optical noise signal V and the optical frequency comb down-converted signal according to the principle that the optical noise signals in the signals are correlated and the optical noise signal and the optical frequency comb down-converted spatial electromagnetic signal are not correlated.

[0101] Step 404, according to the parameters A1 and B1 are obtained. And according to V TRUE光噪声 =A1*V 光噪声 , V TRUE下变频信号 =B1*V 下变频信号 down-converted signal, the real amplitude of the separated signal is recovered.

[0102] Step 405, the separated signal V 光噪声 , V 下变频信号 is computed, and the cross-correlation coefficient of the optical path 2 reference signal after alignment with the time sequence is computed.

[0103] Step 406, if the cross-correlation coefficient is less than 0.1, the separated signal is considered as a signal after eliminating the optical noise and is output; otherwise, it is considered as an optical noise signal.

[0104] In an actual experiment, as shown inFigure 5 The upper curve in the figure is the envelope of the spectrum of the optical path 1 signal before optical noise elimination, and the lower curve is the envelope of the spectrum of the optical path 1 signal after optical noise elimination. Figure 5 The signal in the figure is a common pulse signal directly filled into the MZ modulator using a signal source, the frequency is 1.04 GHz, and the position after frequency down conversion is 2.82 MHz. Figure 5 As can be seen from the figure, the relative intensity noise in the range of 0-20 MHz is eliminated by about 10-30 dB, the optical noise in the range of 90-110 MHz is eliminated by about 20 dB, and the signal-to-noise ratio of the signal is improved by about 18 dB after optical noise elimination.

[0105] By the method described in the embodiment, the elimination of optical relative intensity noise and optical interference noise in a microwave photonics system is realized, the calculation speed is fast, the down-converted signal submerged or blocked by optical noise can be recovered to the maximum extent, and the sensitivity of the system is improved; and the method described in the embodiment does not require strict consistency of the amplitudes and phases of the two optical paths, the phases of the two optical paths can differ by an integer multiple of the repetition frequency period, and the method is easier to implement in engineering.

[0106] According to another aspect of the present application, referring to FIG. 6, Figure 6 A microwave photonics system double optical path cancellation optical noise elimination device 600 is provided, and the device comprises:

[0107] An input module 610 is adapted to receive a pulsed optical source signal and input the pulsed optical source signal into a pre-constructed double optical path;

[0108] A construction module 620 is adapted to collect an output signal of the double optical path and construct the collected output signal of the double optical path into virtual double-channel data;

[0109] A determination module 630 is adapted to determine a down-converted signal from the virtual double-channel data by using a Fast-ICA algorithm, so as to realize elimination of an optical noise signal.

[0110] In some embodiments, the pre-constructed double optical path comprises an optical coupler and a first optical path and a second optical path connected to the optical coupler, the first optical path comprises an optical electric field probe, an optical-electric converter and a low-pass filter connected in series by optical fibers, and the second optical path comprises an optical-electric converter and a low-pass filter connected in series by optical fibers;

[0111] The construction module 620 is adapted to:

[0112] The output signal collected from the first optical path is: S CHA_out (n)=A1*V 光噪声 (n)+B1*V 下变频信号 (n)

[0113] The output signal collected from the second light path is:

[0114] S CHB_out (n) = A2*V 光噪声 (n)

[0115] The constructed virtual double-channel data is:

[0116]

[0117] Wherein, A1, A2 and B1 are parameters determined according to the double light paths, m represents a discrete data point of the first light path signal, n represents a discrete data point of the second light path signal, V 光噪声 is an optical noise signal, V 下变频信号 is a down-converted signal.

[0118] In some embodiments, the constructing module 620 is further adapted to:

[0119] Periodically align or phase align the double light paths.

[0120] In some embodiments, periodically aligning the double light paths comprises:

[0121] Since the V CHA , V CHB and Awgn 光噪声 in the double light path signals S 下变频信号 (m) and S 加性白噪声 (n) are mutually independent, a cross-correlation operation on the double light path signals can obtain:

[0122] R CHA，CHB = E{S CHA (m)*S CHB (n)}

[0123] ≈ E{A1*V 光噪声 (m)*A2*V 光噪声 (n)}

[0124] = A1*A2*R 光噪声 (m-n)

[0125] From the above formula, the cross-correlation of the double light path signals mainly shows the autocorrelation result of the optical noise of the two light paths, and the maximum value appears at the position when the optical noise in the two light paths comes from the same pulse period. Therefore, the period alignment of the double light path signals can be completed by shifting the signal according to the distance of the maximum value point of the cross-correlation envelope from the center line.

[0126] In some embodiments, phase aligning the double light paths comprises:

[0127] Adjust the length of the fiber in the second light path, and according to the display of the oscilloscope, realize the phase alignment of the pulse period.

[0128] In some embodiments, the determining module 630 is adapted to:

[0129] According to the expression of the virtual double-channel data The parameters A1 and B1 are obtained by using the Fast-ICA algorithm.

[0130] According to V TRUE光噪声 =A1*V 光噪声 , V TRUE下变频信号 =B1*V 下变频信号 , the recovery of the true amplitude of the separated signal is completed.

[0131] In some embodiments, the determining module 630 is further adapted to:

[0132] Calculate the cross-correlation coefficient of the separated signal V TRUE光噪声 , V TRUE下变频信号 and the second light path reference signal after time series alignment.

[0133] If the cross-correlation coefficient is less than a preset threshold, the separated signal is considered to be the signal after the optical noise is eliminated, and is output; otherwise, it is considered to be an optical noise signal.

[0134] The embodiment of the application provides a non-volatile readable computer readable storage medium, the computer readable storage medium stores at least one executable instruction, and the computer executable instruction can execute the optical noise elimination method in the above-mentioned any method embodiment.

[0135] Figure 7 The structure schematic diagram of the electronic device embodiment of the application is shown, and the specific implementation of the electronic device is not limited in the specific embodiment of the application.

[0136] As Figure 7 shown, the electronic device can include a processor 702, a communications interface 704, a memory 706, and a communications bus 708.

[0137] The processor 702, the communications interface 704, and the memory 706 can communicate with each other through the communications bus 708. The communications interface 704 is used for communicating with network elements such as clients or other servers. The processor 702 is used for executing the program 1110, and can execute the related steps in the above-mentioned optical noise elimination method for the electronic device.

[0138] In particular, the program 710 can include program code including computer operation instructions.

[0139] The processor 702 can be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to perform the operations of the embodiments of the present application. The one or more processors included in the electronic device can be the same type of processor, such as one or more CPUs, or different types of processors, such as one or more CPUs and one or more ASICs.

[0140] The memory 706 is configured to store the program 710. The memory 706 can include a high-speed RAM memory, and can also include a non-volatile memory, such as at least one disk memory.

[0141] The program 710 can be specifically configured to cause the processor 702 to perform the operations corresponding to the above-mentioned embodiments of the light noise elimination method based on the correlation feature and Fast-ICA.

[0142] The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other apparatus. Various general purpose systems can be used with these teachings, or with modifications that take into account the teachings herein. In accordance with the foregoing description, those skilled in the art can readily construct a structure required to construct such a system. Furthermore, the embodiments of the present application are not directed to any particular programming language. It will be appreciated that the present application described herein can be implemented by using various programming languages, and the description of the specific language above is to disclose the best mode of the present application.

[0143] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not described in detail in order not to obscure the understanding of the present specification.

[0144] Similarly, it is to be understood that the embodiments of the application can be alternately grouped together in a single embodiment, drawing, or description thereof for the purpose of conciseness and to help with the understanding of one or more of the various aspects of the application. However, this method of disclosure is not to be interpreted as reflecting an intention that the claimed application requires more features than the claims do. On the contrary, as the following claims reflect, a separate aspect of the application lies in each separate feature individually. Thus, any claim that depends on another is to be interpreted as alternately standing on its own as a separate embodiment. By way of example, any element in one claim can be combined with any of the elements in another claim to create a new claim.

[0145] Those skilled in the art will appreciate that the modules in the apparatuses in the embodiments can be adapted and placed in one or more apparatuses other than the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and further can be divided into more sub-modules or sub-units or sub-components. Any combination of all the features disclosed in the specification (including the accompanying claims, abstract and drawings), and any method or of the apparatuses disclosed can be taken, except that at least some of such features and / or processes or units are mutually exclusive, unless specifically stated otherwise. Each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by alternative features serving the same, equivalent or similar purpose, unless specifically stated otherwise.

[0146] Furthermore, those skilled in the art will appreciate that different embodiments of the application have different features and that not all embodiments of the application have the same features. For example, in the following claims, any of the claims can be used to enable a single claim to be interpreted to cover one or more embodiments of the application, and an embodiment of the application can be written as any of the claims. The application(s) can relate to each individual embodiment, or a combination of some or all of the embodiments.

[0147] The various component embodiments of the application can be implemented in hardware, or as software modules running in one or more processors, or in combinations thereof. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functionality of some or all of the components according to the embodiments of the application. The application can also be implemented as a program of instructions for performing part or all of the methods described herein, e.g., a computer program and a computer program product. Such program of instructions of the present application can be stored on a computer readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier medium, or in any other form.

[0148] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unitary claim, several devices, systems or means can be listed, comprising means for carrying out a certain task. The use of the term'means' in a claim is intended to refer to a combination of devices, systems or means for performing a task. The word 'first','second', 'third', etc. do not imply any order. The use of these terms is to be construed as use of the terms 'first','second', 'third', etc. to name the names. The steps of the above-described embodiments, unless otherwise specified, are not to be construed as limiting the order of execution.

Claims

1. A method for eliminating phase-extinction noise in a dual-optical-path microwave photonics system, the method comprising: Receive pulsed light source signals and input the pulsed light source signals into a pre-constructed dual optical path; The pre-constructed dual optical path uses a 1:1 power divider to split the light from the femtosecond pulse source into two paths. One path of light goes directly into the photodetector; the other path of light enters the photodetector after passing through an optical electric field sensor. The electrical signals output by the two photodetectors pass through the same low-pass filter bank and are acquired by two channels of the same low-speed acquisition card. The output signals of the dual optical paths are collected, and the collected output signals of the dual optical paths are constructed into virtual dual-channel data; The down-conversion signal is determined from the virtual dual-channel data using the Fast-ICA algorithm, thereby eliminating optical noise signals.

2. The method for eliminating dual-path phase extinction noise in a microwave photonics system according to claim 1, characterized in that, The pre-constructed dual optical path includes an optical coupler and a first optical path and a second optical path connected to the optical coupler. The first optical path includes an optical electric field probe, a photoelectric converter, and a low-pass filter connected in series by optical fibers. The second optical path includes a photoelectric converter and a low-pass filter connected in series by optical fibers. Acquiring the output signals of the dual optical paths and constructing the acquired output signals of the dual optical paths into virtual dual-channel data includes: The output signal collected from the first optical path is: With CHA_out (n)=A1*V 光噪声 (n)+B1*V 下变频信号 (n) The output signal acquired from the second optical path is: SCHB _out (n) = A² * V optical noise(n) The constructed virtual dual-channel data is as follows: Where A1, A2, and B1 are parameters determined based on the dual optical paths, m represents discrete data points of the first optical path signal, n represents discrete data points of the second optical path signal, and V 光噪声 For optical noise signal, V 下变频信号 This is a down-converted signal.

3. The method for eliminating dual-optical-path phase extinction noise in a microwave photonics system according to claim 2, characterized in that, Before acquiring the output signals of the dual optical paths and constructing the acquired output signals of the dual optical paths into virtual dual-channel data, the method further includes: The dual optical paths are periodically and phase-aligned.

4. The method for eliminating dual-path phase extinction noise in a microwave photonics system according to claim 3, characterized in that, Periodic alignment of the dual optical paths includes: Due to the dual-optical-path signal S CHA (m) and S CHB V in (n) 光噪声 V 下变频信号 and Awgn 加性白噪声 Since the signals are uncorrelated pairwise, cross-correlation of the dual optical path signals yields the following: R CHA，CHB =E{S CHA (m)*S CHB (n)} ≈E{A1*V 光噪声 (m)*A2*V 光噪声 (n)} =A1*A2*R 光噪声 (m-n) Among them, R CHA，CHB The cross-correlation between the output signals of the first and second optical paths is represented by E, which represents the desired result. CHA (m) represents the output signal of the first optical path before periodic alignment, S CHB (n) represents the output signal of the second optical path before periodic alignment, m represents the discrete data points of the first optical path signal, n represents the discrete data points of the second optical path signal, and R 光噪声 This represents the autocorrelation of optical noise; As can be seen from the above formula, the cross-correlation of the dual-optical-path signals is mainly manifested as the autocorrelation result of the two optical noises. Its maximum value appears when the optical noise in the two signals comes from the same pulse period. Therefore, by shifting the signal according to the distance of the maximum value point of the cross-correlation envelope from the center line, the period alignment of the dual-optical-path signals can be completed.

5. The method for eliminating dual-optical-path phase extinction noise in a microwave photonics system according to claim 3, characterized in that, Phase alignment of the dual optical paths includes: Adjust the length of the optical fiber in the second optical path and, according to the oscilloscope display, achieve phase alignment of the pulse period.

6. The method for eliminating dual-optical-path phase extinction noise in a microwave photonics system according to claim 2, characterized in that, The Fast-ICA algorithm is used to determine the down-conversion signal from the virtual dual-channel data, thereby eliminating optical noise signals, including: According to the expression of the virtual dual-channel data A1, B1, and V are obtained using the Fast-ICA algorithm. 光噪声 (n) and V 下变频信号 (n); According to V TRUE光噪声 =A1*V 光噪声 V TRUE下变频信号 =B1*V 下变频信号 This completes the recovery of the true amplitude of the separated signal; Among them, V TRUE光噪声 V represents the true optical noise signal after amplitude recovery. TRUE下变频信号 This represents the actual downconverted signal after the amplitude recovery.

7. The method for eliminating dual-optical-path phase extinction noise in a microwave photonics system according to claim 6, characterized in that, Determining the down-conversion signal from the virtual dual-channel data using the Fast-ICA algorithm further includes: Calculate the separated signal V after recovering the true amplitude. TRUE光噪声 V TRUE下变频信号 Cross-correlation coefficient of the second optical path reference signal aligned with the time series; If the cross-correlation coefficient is less than a preset threshold, the separated signal is considered to be the signal after eliminating optical noise and is output; otherwise, it is considered to be an optical noise signal.

8. A dual-path phase extinction noise cancellation device for a microwave photonics system, the device comprising: The input module is adapted to receive pulsed light source signals and input the pulsed light source signals into a pre-constructed dual optical path. The pre-constructed dual optical path uses a 1:1 power divider to split the light from the femtosecond pulsed light source into two paths. One path of light goes directly into the photodetector; the other path of light enters the photodetector after passing through an optical electric field sensor. The electrical signals output by the two photodetectors are collected by two channels of the same low-speed acquisition card through the same low-pass filter bank. The construction module is adapted to acquire the output signals of the dual optical paths and construct the acquired output signals of the dual optical paths into virtual dual-channel data; The determination module is adapted to use the Fast-ICA algorithm to determine the down-conversion signal from the virtual dual-channel data, thereby achieving the elimination of optical noise signals.

9. An electronic device, comprising: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction that causes the processor to perform an operation corresponding to the method according to any one of claims 1-7.

10. A computer-readable storage medium storing at least one executable instruction that causes a processor to perform an operation corresponding to the method according to any one of claims 1-7.

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