An ultra-high-speed large-bandwidth radio frequency spectrum analyzer with 100% capture rate

Abstract

This invention relates to the field of radio frequency (RF) analysis, and particularly to an ultra-high-speed RF spectrometer with a 100% capture rate. It comprises a mode-locked fiber laser connected by optical fibers, a bandpass optical filter, a first chirped Bragg grating, a second chirped Bragg grating, a modulator, and a photodetector. The mode-locked fiber laser generates a pump signal; the optical filter filters out the ultra-high repetition rate optical pulse signal emitted by the mode-locked fiber laser; the first and second chirped Bragg gratings are in series, providing a large amount of second-order dispersion and eliminating third-order and higher-order dispersion; the modulator loads any radio frequency signal to be measured onto the optical pulse signal; and the photodetector converts the optical pulse radio frequency signal into a corresponding electrical radio frequency signal for output. This invention achieves a 100% capture rate, a measurement frame rate of over 100 MHz, and a measurement bandwidth of over tens of GHz, effectively filling a current technological gap.

Description

Technical Field

[0001] This invention relates to the field of radio spectrum analysis, and particularly to an ultra-wide bandwidth radio spectrometer, and more specifically to an ultra-high speed radio spectrometer with 100% capture rate. Background Technology

[0002] Radio frequency (RF) analysis refers to the method of transforming time-domain signals to the frequency domain for analysis. It involves performing a Fourier transform on the amplitude envelope of the field to obtain the spectral intensity. With the increasing complexity of electromagnetic environments, fields such as radar and wireless communication typically require RF analyzers to have real-time analysis capabilities. Key parameters include resolution, bandwidth, frame rate, and capture rate. Resolution refers to the minimum frequency interval that can be precisely distinguished between two frequencies. Bandwidth refers to the frequency range within which the system can operate. Frame rate describes the number of spectra that the system can capture per second, reflecting the system's measurement rate. Capture rate refers to the degree of continuous signal acquisition. Currently, Keysight's commercial RF spectrometer, model N9041B, while achieving Hz-level resolution and a maximum bandwidth of 110 GHz, has a refresh rate only in the Hz-kHz range.

[0003] RF analyzers based on time-domain optics overcome the low measurement speed of electrospectroscopy. Utilizing a joint time-frequency distribution, they can intuitively and quickly solve for the frequency domain characteristics of a given high-speed time-domain signal, achieving real-time RF analysis. However, time-domain optics-based RF analyzers are limited by the mapping mechanism, with frame rates typically on the order of 10MHz, and bandwidth limited to below 40GHz due to system distortion. Furthermore, because the time analysis windows do not overlap (i.e., gaps exist between windows), continuous time signals are truncated by discontinuous time analysis windows. Therefore, the signal capture rate of this approach is typically below 50%, ultimately leading to the loss of some time signals.

[0004] To overcome the shortcomings of time-domain optics-based spectral analyzers, the dispersive delay line is designed to satisfy the Talbot self-imaging condition, which is an integer multiple of the pulse sampling rate. This allows for good resolution of the spectra of continuous and heavily overlapping time signals at the system output, achieving a resolution of 340 MHz and a 100% capture rate (SR Konatham, et al., Real-time gap-free dynamic waveform spectral analysis with nanosecond resolutions through analog signal processing, Nature Communications, 11, 3309 (2020)). However, limited by the time-domain Talbot effect mechanism, the system bandwidth of this scheme is less than 3 GHz, severely restricting its applicability. Therefore, current technology struggles to simultaneously achieve 100% signal capture rate, ultra-high speed with frame rates exceeding 100 MHz, and large bandwidth exceeding tens of GHz, resulting in technological gaps in related radar and other applications. Summary of the Invention

[0005] The technical problem to be solved by this invention is to propose an ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate, so as to make up for the shortcomings of current technology in signal capture rate and frame rate, and expand the application scope of radio frequency analysis.

[0006] To solve the above-mentioned technical problems, the present invention proposes an ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate, comprising a mode-locked fiber laser, a bandpass optical filter, a first chirped Bragg grating, a second chirped Bragg grating, a modulator, and a photodetector connected by optical fibers.

[0007] The mode-locked fiber laser is used to generate optical pulses with a repetition frequency of over 100 MHz as pump signals.

[0008] The optical filter is used to receive the ultra-high repetition rate optical pulse signal emitted by the mode-locked fiber laser, and then filter out a portion of the spectrum as an analysis window;

[0009] The first chirped Bragg grating and the second chirped Bragg grating form a serial structure. The first chirped Bragg grating provides a large amount of second-order dispersion and accumulates a small amount of third-order and higher-order dispersion, while the second chirped Bragg grating provides the opposite small amount of second-order dispersion and the opposite large amount of third-order and higher-order dispersion, thereby achieving the goal of providing a large amount of second-order dispersion while eliminating third-order and higher-order dispersion.

[0010] The modulator is used to load any radio frequency signal under test onto an optical pulse signal that has a large amount of second-order dispersion while eliminating third-order and higher-order dispersion.

[0011] The photodetector is used to collect the pulse signal output from the positive port of the second chirped Bragg grating and convert the optical pulse radio frequency signal into a corresponding electrical radio frequency signal for output.

[0012] Furthermore, the first chirped Bragg grating and the second chirped Bragg grating form a serial structure. Specifically, the forward port of the first chirped Bragg grating performs dispersion stretching on the filtered optical pulse signal, and the dispersion-stretched optical pulse signal enters the reverse port of the second chirped Bragg grating. The reverse port of the second chirped Bragg grating performs a first third-order or higher-order dispersion compensation on the optical pulse signal, and the optical pulse signal loaded with the radio frequency signal under test after the first third-order or higher-order dispersion compensation enters the reverse port of the first chirped Bragg grating. The reverse port of the first chirped Bragg grating performs dispersion compression on the modulated optical pulse signal, and the dispersion-compressed optical pulse signal enters the forward port of the second chirped Bragg grating. The forward port of the second chirped Bragg grating performs a second third-order or higher-order dispersion compensation on the dispersion-compressed optical pulse signal.

[0013] Furthermore, the first chirped Bragg grating disperses and stretches the optical pulse signal, ensuring that the spectral information of the continuous time signal within a certain time analysis window does not overlap with that of adjacent time analysis windows.

[0014] Preferably, the ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate of the present invention has the following parametric characteristics:

[0015]

[0016] Among them, T r Let Φ be the time-domain period of the optical pulse signal, Φ be the total dispersion of the optical pulse signal, and Δω be the total dispersion of the optical pulse signal. p Δω represents the spectral width of a bandpass optical filter. r T is the operating bandwidth of the radio spectrum analyzer. rmin This represents the minimum value of the laser's time-domain period.

[0017] Preferably, the ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate of the present invention has the following parametric characteristics:

[0018]

[0019] The repetition frequency of the optical pulse signal is f. rep =1 / T r f repmax This represents the maximum repetition frequency of the laser.

[0020] Preferably, the filter is a bandpass optical filter.

[0021] The specific principles of this invention are as follows:

[0022] 1) The output pulse signal of a mode-locked fiber laser with an ultra-high repetition rate is given by a time-domain period of T. r Then its repetition frequency is f rep =1 / T r Suppose that the bandpass optical filter has Δω p The spectral width, and assuming the filtered optical pulse has A fliter The envelope of (t) and the pulse width of τ. Since mode-locked fiber lasers can achieve repetition frequencies above GHz, the spectrometer of this invention has ultra-high-speed characteristics.

[0023] 2) The cascaded combination of the first and second chirped Bragg gratings performs dispersion stretching on the filtered light pulse. Through reasonable dispersion design, a dispersion combination with near-zero second-order dispersion and third-order and higher-order dispersions is achieved. Assuming the total dispersion of the dispersion combination is Φ, then the pulse envelope A... fliter (t) becomes envelope A after undergoing dispersion. disp (t):

[0024]

[0025] In the formula, A p (t) represents the aperture function. In particular, when the dispersion Φ is much greater than the pulse width τ, that is, when Φ >> τ, the aperture function A p (t) The term can be ignored, and it can be simplified to:

[0026]

[0027] Here, FT represents the Fourier transform of the signal.

[0028] 3) The modulator loads the time signal u(t) to be measured onto the stretching optical pulse. Let the signal have a Δω u If the spectral width is such that the envelope of the modulated optical pulse becomes A' disp (t):

[0029] A' disp (t)=A disp (t)×u(t) ⑶

[0030] 4) When the opposite port of the chirped Bragg grating combination is compressed, the total dispersion of the dispersion combination is -Φ, and the envelope of the final output light pulse becomes v(t):

[0031]

[0032] As can be seen from formula (4), the time signal to be measured, u(t), is first affected in time by the aperture function A. p (t) Windowing is applied, and then the spectrum corresponding to the time signal under test is mapped along the time domain. The frequency-to-time mapping relationship satisfies:

[0033] Δt=|Φ|Δω ⑸

[0034] In existing real-time RF analysis schemes, to avoid signal aliasing, overlapping stretch pulses are not allowed, which can be described by the formula:

[0035] T r >|Φ|Δω p 6

[0036] However, there are gaps between non-overlapping stretching pulses. When a continuous time signal is loaded, this discontinuous time analysis window, composed of stretching pulses with gaps, will cause the continuous time signal to be truncated by the window during loading, resulting in information loss, which means that a 100% capture rate cannot be achieved.

[0037] This invention has found that when the dispersion is large enough to cause partial overlap of the stretching pulses, according to formula (4), the spectral information of the continuous-time signal to be measured will appear simultaneously in multiple time analysis windows corresponding to it. In other words, the overlap of time analysis windows essentially means that the spectral information of the continuous-time signal to be measured corresponding to the overlapping portion will appear repeatedly in multiple time analysis windows, without affecting the different time analysis windows. Therefore, when using large dispersion to cause partial overlap of the stretching pulses, it is only necessary to ensure that the spectral information of the continuous-time signal in a certain time analysis window does not overlap with adjacent time analysis windows, thus preventing crosstalk, to achieve a 100% signal capture rate. This can be described by the formula:

[0038]

[0039] Where, Δω p Δω represents the spectral width of a bandpass optical filter. r T is the system's operating bandwidth. rmin This is the minimum value of the laser's time-domain period. The upper part of Equation (7) describes the condition requiring large dispersion to cause the stretched pulses to overlap in order to achieve a 100% signal capture rate, while the lower part of Equation (7) describes the condition that the spectral information of the continuous-time signal does not alias with adjacent time analysis windows, thus preventing crosstalk. Furthermore, it should be noted that for a bandwidth of Δω... u The modulator, when the modulation mode is single-sideband modulation, Δω r =Δω u When the modulation method is double-sideband modulation, Δω r =2Δω u .

[0040] f rep =1 / T r Substituting into formula (7), we can obtain the formula described by frame rate:

[0041]

[0042] Among them, f repmax This is the maximum repetition frequency of the laser, which is also the maximum frame rate of the system.

[0043] 5) A high-bandwidth photodetector converts optical signals into electrical signals, which can be observed using a high-speed real-time oscilloscope, thus achieving a frame rate of f. rep Ultra-high-speed real-time RF spectrum analysis with 100% capture rate. When the pulse width of the pulse signal acquired by the real-time oscilloscope is τ... o At that time, the system resolution δf is:

[0044]

[0045] The above derivation applies to ultra-narrow pulses with pulse widths on the order of ps and below, and to any pure second-order dispersion module. Under the condition of satisfying formula (7), a 100% signal capture rate can be achieved. Meanwhile, as shown in formula (8), the reciprocal of the dispersion |Φ| determines the system's frame rate f. rep With the system bandwidth Δω r The upper limit of the product is that the smaller the dispersion |Φ|, the larger the product. However, as shown in formula (9), a decrease in dispersion |Φ| will lead to a deterioration in system resolution. Therefore, in actual system design, a trade-off can be made according to the requirements. For example, in application scenarios where resolution requirements are not high, appropriately reducing dispersion |Φ| can achieve a higher frame rate or bandwidth. Secondly, in the case of third-order and higher-order dispersion elimination, the system bandwidth is mainly limited by the modulator bandwidth. Existing on-chip modulators have achieved a bandwidth of 100GHz, so the current system bandwidth can achieve 100GHz. As the modulator bandwidth is further expanded, the system bandwidth will be expanded accordingly. Therefore, this system can achieve 100% signal capture and ultra-high-speed RF analysis, and its frame rate and detection bandwidth can be flexibly designed according to actual needs.

[0046] In summary, theoretical and experimental results demonstrate that the ultra-high-speed, wide-bandwidth RF spectrometer with 100% capture rate proposed in this invention can achieve a 100% capture rate, a measurement frame rate of over 100 MHz, and a measurement bandwidth of over tens of GHz, effectively filling a current technological gap. Furthermore, the use of a chirped Bragg grating, which has both small size and low loss, effectively reduces the size of the RF spectrometer and improves the system signal-to-noise ratio. Attached Figure Description

[0047] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments; however, the large bandwidth arbitrary second-order dispersion module and modulator applicable to time-domain optics of the present invention are not limited to the embodiments.

[0048] Figure 1 This is a schematic diagram of the structure of the ultra-high-speed radio frequency analyzer with 100% signal capture, which is a specific embodiment of the present invention.

[0049] Figure 2 (a) is the time analysis window for partial overlap after dispersive stretching in Case Study 1.

[0050] Figure 2 (b) To implement the continuous radio frequency signal modulation on the time analysis window in Case 1.

[0051] Figure 2 (c) is the final output RF spectrum in Implementation Case 1.

[0052] Figure 3 This is a bandwidth characterization diagram of the radio spectrometer used in Case Study 1.

[0053] Figure 4 This is a characterization diagram of the mapping accuracy of the radio spectrometer in Case Study 1.

[0054] Figure 5 This is a resolution characterization diagram of the radio spectrometer used in Case Study 1.

[0055] Figure 6 (a) is the time analysis window for partial overlap after dispersive stretching in Case Study 2.

[0056] Figure 6 (b) To implement the continuous radio frequency signal modulation on the time analysis window in Case 2.

[0057] Figure 6 (c) is the final output RF spectrum in Implementation Case 2.

[0058] Figure 7 This is a bandwidth characterization diagram of the radio spectrometer used in Case Study 2.

[0059] Figure 8 The mapping accuracy characterization diagram for the RF spectrometer in Case Study 2.

[0060] Figure 9 The resolution characterization diagram of the RF spectrometer used in Case Study 2.

[0061] Figure 10 (a) is a characterization diagram of the ability of the RF spectrometer in Case 2 to identify combinations of single-frequency signals and swept-frequency signals in real time.

[0062] Figure 10(b) The recognition result of the signal at a given time in Case 2.

[0063] Figure 11 (a) is a characterization diagram of the ability of the RF spectrometer in Case 2 to identify combinations of single-frequency signals and frequency-hopping signals in real time.

[0064] Figure 11 (b) The recognition result of the signal at a given time in Case 2. Detailed Implementation

[0065] like Figure 1 The diagram shown is a schematic representation of a high-speed real-time radio spectrometer with 100% capture rate according to a specific embodiment of the present invention. This diagram is not a connection diagram of the actual device. The high-speed real-time radio spectrometer with 100% capture rate includes a mode-locked fiber laser 1, a bandpass optical filter 2, a forward port 3 of a first chirped Bragg grating, a reverse port 4 of a second chirped Bragg grating, a modulator 5, a reverse port 6 of the first chirped Bragg grating, a forward port 7 of the second chirped Bragg grating, and a photodetector 8.

[0066] Among them, the mode-locked fiber laser 1 utilizes existing mature products, which generates ultra-high frame rate optical pulses with a repetition frequency of over 100 MHz as pump signals, enabling the RF spectrometer of the present invention to have ultra-high speed performance.

[0067] The bandpass optical filter 2 receives the ultra-high repetition rate optical pulse signal emitted by the mode-locked fiber laser, and then filters out a portion of the spectrum to be used as an analysis window.

[0068] The first chirped Bragg grating and the second chirped Bragg grating form a serial structure. The first chirped Bragg grating provides a large amount of second-order dispersion and accumulates a small amount of third-order and higher-order dispersion, while the second chirped Bragg grating provides the opposite small amount of second-order dispersion and the opposite large amount of third-order and higher-order dispersion. This achieves the goal of providing a large amount of second-order dispersion while eliminating third-order and higher-order dispersion, thereby avoiding pulse broadening and nonlinear mapping caused by third-order and higher-order dispersion, and thus expanding the measurement bandwidth of the system.

[0069] Specifically, the serial structure involves the following steps: the forward port 3 of the first chirped Bragg grating performs dispersion stretching on the filtered optical pulse signal; the reverse port 4 of the second chirped Bragg grating performs first-order or higher-order dispersion compensation on the stretched optical pulse signal; the modulator 5 loads any radio frequency signal to be tested onto the stretched optical pulse signal; the reverse port 6 of the first chirped Bragg grating performs dispersion compression on the optical pulse signal modulated by the modulator; and the forward port 7 of the second chirped Bragg grating performs further third-order or higher-order dispersion compensation on the dispersion-compressed optical pulse signal.

[0070] Unlike existing time-domain optics-based RF spectrometers that do not allow overlap caused by dispersion stretching, the RF spectrometer of this invention features a large amount of second-order dispersion in the optical pulse signal, causing partial overlap of the stretched optical pulses. This eliminates gaps in the real-time time analysis window, thereby ensuring 100% signal capture of the loaded RF signal. Simultaneously, based on the dispersion stretching of the optical pulse signal, the spectral information of continuous time signals within a certain time analysis window is prevented from aliasing with adjacent time analysis windows, thus overcoming signal crosstalk caused by signal aliasing between adjacent time analysis windows that is easily generated by dispersion stretching. Having simultaneously achieved the above two objectives, the RF spectrometer of this invention has the following parametric characteristics:

[0071]

[0072] Among them, T r Let Φ be the time-domain period of the optical pulse signal, Φ be the total dispersion of the optical pulse signal, and Δω be the total dispersion of the optical pulse signal. p Δω represents the spectral width of a bandpass optical filter. r T is the operating bandwidth of the radio spectrum analyzer. rmin This represents the minimum value of the laser's time-domain period.

[0073] The time-frequency domain transform is expressed with the following parametric characteristics:

[0074]

[0075] The repetition frequency of the optical pulse signal is f. rep =1 / T r f repmax This represents the maximum repetition frequency of the laser.

[0076] In addition, chirped Bragg gratings have smaller size and lower loss, which can effectively reduce system size and improve system signal-to-noise ratio.

[0077] Table 1 below shows several sets of performance indicators that can be achieved simultaneously by the present invention for different dispersion values ​​|Φ|. The center wavelength of the simulated bandpass optical filter is 1550nm, the 3dB bandwidth is 1.5nm, the modulation method is single-sideband modulation, and the electrical bandwidth limit of 59GHz is simulated.

[0078] Table 1 shows the performance parameters that can be achieved simultaneously under different dispersion levels according to the present invention.

[0079] <![CDATA[Dispersion amount |Φ| (ps 2 )]]> <![CDATA[Frame frequency f rep (MHz)]]> <![CDATA[Bandwidth Δf r (GHz)]]> Resolution δf (MHz) 3000 530 100 390 3000 265 200 395 2000 795 100 590 2000 397 200 580 1000 1590 100 1200 1000 795 200 1220

[0080] Example 1

[0081] To verify that the proposed scheme can theoretically realize an ultra-high-speed real-time RF analyzer with a 100% capture rate, this scheme simulates and demonstrates a real-time RF analyzer with a frame rate of 500MHz, a bandwidth of more than 100GHz, and a resolution of 400MHz, thus verifying that the proposed scheme can realize an ultra-high-speed real-time RF analyzer with a 100% capture rate.

[0082] Figure 1 A schematic diagram of an ultra-high-speed real-time radio spectrum analyzer with 100% capture rate is shown in a specific embodiment of the present invention.

[0083] Figure 2 (a) shows the partial overlap of a 500MHz optical pulse after dispersion stretching, resulting in a distinct interference pattern. The dispersion module simulates the elimination of third-order and higher-order dispersion, with a total dispersion of Φ = 3000 ps. 2 Dispersion of the third order and above can be ignored.

[0084] Figure 2 (b) shows that when the intensity modulator loads a 5 GHz cosine signal onto the stretching pulse, the signal is captured by 100%.

[0085] Figure 2 (c) gives the final radio spectrum of the 5 GHz cosine signal mapped in the time domain. The single-sideband carrier suppression modulation method is used. In each time analysis window, the pulse is mapped only to the right of the pump pulse (the pulse with reduced intensity). The interval between adjacent time analysis windows is 2 ns, corresponding to a frame rate of 500 MHz.

[0086] Figure 3 The bandwidth characterization diagram of this RF spectrometer verifies an operating bandwidth greater than 100 GHz.

[0087] Figure 4 This is a graph characterizing the mapping accuracy of the local RF spectrometer. The RF signal was swept from 2 GHz to 100 GHz, and the actual mapped frequency matched the set frequency.

[0088] Figure 5 This is a resolution characterization diagram of the local spectral analyzer. Under the bandwidth limitation of a real-time oscilloscope simulating 59 GHz, the resolution of the local spectral analyzer is below 400 MHz within its system bandwidth.

[0089] Example 2

[0090] To verify that this scheme can actually realize a high-speed real-time radio spectrum analyzer with a 100% capture rate, according to formula (8), the frame rate of the system can be arbitrarily selected according to actual needs. In this scheme, a real-time radio spectrum analyzer with a frame rate of 233MHz, a bandwidth greater than 60GHz, and a resolution of up to 600MHz with a 100% capture rate was experimentally implemented, which verified that this scheme can realize a high-speed real-time radio spectrum analyzer with a 100% capture rate.

[0091] A schematic diagram of an ultra-high-speed real-time radio spectrum analyzer with 100% capture rate, specifically implemented in the present invention, is still shown. Figure 1 As shown.

[0092] Figure 6 (a) shows the partial overlap of a 233 MHz optical pulse after dispersion stretching, resulting in a distinct interference pattern. The dispersion of the first and second chirped Bragg gratings, after proper design, yields a total dispersion of Φ = 4320 ps. 2 Dispersion of the third order and above can be ignored.

[0093] Figure 6 (b) shows that when the intensity modulator loads a 5 GHz cosine signal onto the stretching pulse, the signal is captured 100%, where the bandwidth of the intensity modulator is 40 GHz.

[0094] Figure 6 (c) gives the final radio spectrum of the 5 GHz cosine signal mapped in the time domain. Due to the use of double-sideband carrier suppression modulation, two symmetrical pulses are presented in each time analysis window. The interval between adjacent time analysis windows is 4.29 ns, corresponding to a frame rate of 233 MHz.

[0095] Figure 7 The image shows the bandwidth characterization of the local RF spectrometer. Due to the 40 GHz bandwidth of the intensity modulator, the signal power above 40 GHz is significantly attenuated, but the working bandwidth of more than 60 GHz is still verified.

[0096] Figure 8 This is a graph characterizing the mapping accuracy of the local RF spectrometer. The RF signal was swept from 1 GHz to 60 GHz, and the actual mapped frequency matched the set frequency.

[0097] Figure 9 This is a resolution characterization graph for the local RF spectrometer. Using a high-speed PD probe with a 70 GHz bandwidth and observed on a Keysight DSAZ594 real-time oscilloscope, the resolution was below 600 MHz within the system bandwidth.

[0098] Figure 10(a) This characterizes the real-time frequency identification capability of the local spectral analyzer for a combination of a 10 GHz single-frequency signal and a 6-14 GHz swept-frequency signal. Each loop represents a 4.29 ns time interval, or a 233 MHz frame rate. At any given moment, the frequencies of the two signals can be accurately identified. The frequency of the single-frequency signal does not change with time and is represented as a flat line in the graph; while the frequency of the swept-frequency signal changes continuously with time and is represented as a continuous diagonal line in the graph.

[0099] Figure 10 (b) is Figure 10 (a) shows the frequency identification results at the times corresponding to the three dashed lines. The two signals were accurately distinguished, and obvious interference occurred when the frequencies of the two signals were close.

[0100] Figure 11 (a) This characterizes the real-time frequency identification capability of the local spectral analyzer for combinations of 2-6 GHz swept signals and 8-12 GHz frequency hopping signals. At any given moment, the frequencies of both signals can be accurately identified. Similarly, the frequency of the swept signal changes continuously over time, appearing as a continuous diagonal line in the figure; while the frequency of the frequency hopping signal remains constant for a period of time before suddenly jumping to another frequency, appearing as a discontinuous step in the figure.

[0101] Figure 11 (b) is Figure 11 (a) shows the frequency identification results at the times corresponding to the three dashed lines, indicating that the two signals were accurately distinguished.

[0102] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-speed, wide-bandwidth radio spectrometer with 100% capture rate, characterized in that, It includes a mode-locked fiber laser connected by optical fibers, a bandpass optical filter, a first chirped Bragg grating, a second chirped Bragg grating, a modulator, and a photodetector; The mode-locked fiber laser is used to generate optical pulses with a repetition frequency of over 100 MHz as pump signals. The optical filter is used to receive the ultra-high repetition rate optical pulse signal emitted by the mode-locked fiber laser, and then filter out a portion of the spectrum as an analysis window; The first chirped Bragg grating and the second chirped Bragg grating form a serial structure. The first chirped Bragg grating provides a large amount of second-order dispersion and accumulates a small amount of higher-order dispersion, while the second chirped Bragg grating provides the opposite small amount of second-order dispersion and the opposite large amount of third-order and higher-order dispersion, thereby achieving the goal of providing a large amount of second-order dispersion while eliminating third-order and higher-order dispersion. The modulator is used to load any radio frequency signal under test onto an optical pulse signal that has a large amount of second-order dispersion while eliminating third-order and higher-order dispersion. The photodetector is used to collect the pulse signal output from the positive port of the second chirped Bragg grating and convert the optical pulse radio frequency signal into a corresponding electrical radio frequency signal for output.

2. The ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate according to claim 1, characterized in that, The first chirped Bragg grating and the second chirped Bragg grating form a serial structure, specifically, The forward port of the first chirped Bragg grating performs dispersion stretching on the filtered light pulse signal, and the dispersion-stretched light pulse signal enters the reverse port of the second chirped Bragg grating. The inverting port of the second chirped Bragg grating performs a first third-order or higher-order dispersion compensation on the optical pulse signal. After the first third-order or higher-order dispersion compensation, the optical pulse signal loaded with the radio frequency signal under test enters the inverting port of the first chirped Bragg grating. The inverting port of the first chirped Bragg grating performs dispersion compression on the modulated optical pulse signal, and the dispersion-compressed optical pulse signal enters the forward port of the second chirped Bragg grating. The forward port of the second chirped Bragg grating performs third-order or higher-order dispersion compensation on the dispersion-compressed optical pulse signal.

3. The ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate according to claim 2, characterized in that, The first chirped Bragg grating disperses and stretches the optical pulse signal, preventing the spectral information of the continuous time signal within a certain time analysis window from overlapping with that of adjacent time analysis windows.

4. The ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate according to claim 3, characterized in that, It has the following parametric characteristics: Among them, T r Let Φ be the time-domain period of the optical pulse signal, Φ be the total dispersion of the optical pulse signal, and Δω be the total dispersion of the optical pulse signal. p Δω represents the spectral width of a bandpass optical filter. r T is the operating bandwidth of the radio spectrum analyzer. rmin This represents the minimum value of the laser's time-domain period.

5. The ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate according to claim 3, characterized in that, It has the following parametric characteristics: Where Φ is the total dispersion of the optical pulse signal, and the repetition frequency of the optical pulse signal is f. rep =1 / T r T r Let Δω be the time-domain period of the optical pulse signal. p Δω represents the spectral width of a bandpass optical filter. r f is the operating bandwidth of the radio spectrometer. repmax This represents the maximum repetition frequency of the laser.

6. The ultra-high-speed, wide-bandwidth radio spectrometer with 100% capture rate according to claim 1, characterized in that, The filter is a bandpass optical filter.

Images