A dual-band radio frequency signal channelization system

Abstract

The present application provides a dual-band radio frequency signal channelization system, characterized in that it includes a polarization modulation-dual-drive Mach-Zehnder modulator, a polarization phase diversity coherent receiver, a first 90° electrical mixer, and a second 90° electrical mixer. The two-way dual-band radio frequency signals are modulated to two polarization states of an optical carrier through the polarization modulation-dual-drive Mach-Zehnder modulator to achieve separate transmission of the two-way dual-band radio frequency signals, thereby improving the utilization efficiency of a single optical carrier link. At the same time, the local oscillator light is used in the polarization phase diversity coherent receiver to confirm the cutting point of the two-way dual-band radio frequency signals, and to complete the photoelectric conversion, while suppressing harmonic components such as radio frequency leakage and mixed spurious, and finally the first 90° electrical mixer and the second 90° electrical mixer are used to complete the channelization cutting, thereby achieving the output of four-way split signals of the two-way dual-band radio frequency signals, thereby completing signal separation.

Description

Technical Field

[0001] The present application relates to the field of microwave photons and microwave photon communication technology, and in particular to a dual-band radio frequency signal channelization system. Background Art

[0002] In recent years, 5G communications, satellite communications, radar systems, and many other industries have required signals to develop towards higher frequencies, larger bandwidths, and more frequency bands. Therefore, high-performance receivers with large instantaneous bandwidth, high resolution, large dynamic range, and the ability to process multi-frequency signals are urgently needed.

[0003] The main process of channelized reception is to divide the received broadband radio frequency (RF) signal in the frequency domain, realize the single input of broadband RF signal, multiple output of narrowband low-frequency signal, and receive signals of different bands in real time and in parallel, with high sensitivity and frequency resolution. Traditional analog channelized receivers are composed of microwave devices, which leads to extremely high loss in high frequency bands and cannot achieve uniform high performance over multiple octaves. Digital channelization is based on the design of digital filter arrays, which can flexibly divide channels and switch outputs through integrated chips such as FPGA. However, using DSP to mine target information with high fidelity poses great challenges to high-speed processing chips, high-speed sampling modules and high-storage memories.

[0004] To this end, microwave photon-based channelization technology, with its advantages of low loss, light weight, small size, large bandwidth and anti-electromagnetic interference, breaks through the electronic bottleneck encountered in the traditional microwave field and has become a current research hotspot. One method is to form an optical filter array based on a set of optical filters with continuous passbands, such as Bragg grating Fabry-Perot cavities, to divide broadband signals into many sub-signals. However, this method usually requires optical filters with flat-top and steep edge frequency responses, which makes device manufacturing quite difficult. Another method is to multicast broadband RF signals on an optical frequency comb (OFC), and then use a filter with a free spectrum range (FSR) slightly detuned from the comb line spacing to generate narrowband signals, or generate a local oscillator optical frequency comb to mark the cutting position of the broadband signal. This type of method has a complex structure and is not conducive to photonic integration. At present, the most advanced commercial FPGA can process 5GHz bandwidth signals, and the bandwidth requirement of a single signal in the millimeter wave band is not large. Therefore, based on the existing technical level and application requirements, a simple, flexible, configurable dual-channel channelizer that can meet large bandwidth and high-frequency signals is the most worthy of study. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a dual-band radio frequency signal channelization system.

[0006] Based on the above purpose, the present application provides a dual-band radio frequency signal channelization system, including a polarization modulation-dual-drive Mach-Zehnder modulator, a polarization phase diversity coherent receiver, a first 90° electrical mixer and a second 90° electrical mixer;

[0007] The polarization modulation-dual-drive Mach-Zehnder modulator is used to divide the optical carrier emitted by the laser into a first optical carrier of X polarization and a second optical carrier of X polarization, and load the first dual-band radio frequency signal connected to the first optical carrier of X polarization to form a first modulated signal of X polarization, and load the second dual-band radio frequency signal connected to the second optical carrier of X polarization to form a second modulated signal of X polarization; at the same time, the second modulated signal of X polarization is polarized by 90° to form a second modulated signal of Y polarization; the polarization modulation-dual-drive Mach-Zehnder modulator is also used to combine the first modulated signal of X polarization and the second modulated signal of Y polarization to output a total modulated signal; wherein the first dual-band radio frequency signal carries a first signal and a second signal, and the second dual-band radio frequency signal carries a third signal and a fourth signal;

[0008] The polarization controller is used to input the total modulated signal into the polarization phase diversity coherent receiver;

[0009] The polarization phase diversity coherent receiver is used to beat the total modulated signal with a preset local oscillator light, and perform photoelectric conversion to output a first beat signal, a second beat signal, a third beat signal and a fourth beat signal;

[0010] The first 90° electrical mixer is used to perform channel separation on the first beat frequency signal and the second beat frequency signal to obtain the first signal and the second signal, and the second 90° electrical mixer is used to perform channel separation on the third beat frequency signal and the fourth beat frequency signal to obtain the third signal and the fourth signal.

[0011] Optionally, the polarization modulation-dual-drive Mach-Zehnder modulator includes an optical coupler, a first sub-Mach-Zehnder modulator, a second sub-Mach-Zehnder modulator, a 90° polarization rotator and a polarization beam combiner;

[0012] The optical coupler is used to divide the optical carrier into a first optical carrier and a second optical carrier, wherein the first optical carrier and the second optical carrier are the same;

[0013] The first sub-Mach-Zehnder modulator is used to modulate the first optical carrier into the first optical carrier of the X polarization, and modulate the first signal and the second signal carried by the first dual-band broadband radio frequency signal onto the first optical carrier of the X polarization respectively, and output the first modulated signal of the X polarization;

[0014] The second sub-Mach-Zehnder modulator is used to modulate the second optical carrier into the second optical carrier of the X polarization, and modulate the third signal and the fourth signal carried by the second dual-band broadband radio frequency signal onto the second optical carrier of the X polarization respectively, and output the second modulated signal of the X polarization; the 90° polarization rotator performs a 90° polarization rotation on the second modulated signal of the X polarization to form a second modulated signal of the Y polarization;

[0015] The polarization beam combiner is used to combine the X-polarized first modulation signal and the Y-polarized second modulation signal into the total modulation signal.

[0016] Optionally, the polarization phase diversity coherent receiver includes a first polarization beam splitter, a second polarization beam splitter, a first 90° optical mixer, a second 90° optical mixer, a first balanced detector group, and a second balanced detector group;

[0017] The first polarization beam splitter uses X polarization and Y polarization to separate the first modulation signal of X polarization and the second modulation signal of Y polarization respectively, and inputs the separated first modulation signal of X polarization and the separated second modulation signal of Y polarization into the first 90° optical mixer and the second 90° optical mixer respectively;

[0018] The second polarization beam splitter is used to split the preset local oscillation light into a first local oscillation light and a second local oscillation light, and input the first local oscillation light and the second local oscillation light into a first 90° optical mixer and a second 90° optical mixer respectively, wherein the first local oscillation light and the second local oscillation light are the same;

[0019] The first 90° optical mixer is used to phase shift the first local oscillator light, and superimpose it with the separated X-polarized first modulation signal, output a superimposed signal of four X-polarized first modulation signals and the phase-shifted first local oscillator light, and input it into a first balanced detector group;

[0020] The second 90° optical mixer is used to phase shift the second local oscillator light, and superimpose it with the separated Y-polarized second modulation signal, output four-way Y-polarized second modulation signal and the superimposed signal of the second local oscillator light, and input it into the second balanced detector group;

[0021] The first balanced detector group respectively beats the four input X-polarized first modulation signals with the superimposed signal of the first local oscillation light to form a first beat signal and a second beat signal; the second balanced detector group respectively beats the four input Y-polarized second modulation signals with the superimposed signal of the second local oscillation light to convert them into a third beat signal and a fourth beat signal.

[0022] Optionally, a polarization controller is further included, which is connected between the polarization beam combiner and the first polarization beam splitter and is used to control the X polarization state of the total modulated signal to be aligned with the main axis of the first polarization beam splitter to depolarize the total modulated signal.

[0023] Optionally, the first signal and the second signal waveforms are a1(t) and a2(t), the center frequencies are ω1 and ω2, and the bandwidths are B a1 , B a2 The waveforms of the third signal and the fourth signal are a3(t) and a4(t), the center frequencies are ω3 and ω4, and the bandwidths are B b1 , B b2 , the optical carrier frequency is ω c , the preset local oscillator frequency is ω LO , which satisfies

[0024] Optionally, a first DC bias voltage is input to the DC bias voltage input port of the first sub-Mach Zehnder, so that the first sub-Mach Zehnder modulator operates at a minimum bias point to implement carrier suppressed double-sideband modulation, so that the first dual-band broadband signal is modulated onto the first optical carrier of X polarization and the first modulated signal of X polarization is output; a second DC bias voltage is input to the DC bias voltage input port of the second sub-Mach Zehnder, so that the second sub-Mach Zehnder modulator operates at a minimum bias point to implement carrier suppressed double-sideband modulation, so that the second dual-band broadband signal is modulated onto the second optical carrier of X polarization and the second modulated signal of X polarization is output.

[0025] Optionally, the X-polarized first modulated signal output is:

[0026]

[0027] Where β1=π / V π1 is the modulation index of the first dual-band RF signal, V π1 is the first DC bias voltage, J n (·) is the first kind nth order Bessel function, E in (t) is the optical carrier emitted by the laser, a1(t)cosω1t+a2(t)cosω2t is the first dual-band RF signal;

[0028] The second modulated signal output of the Y polarization is:

[0029]

[0030] Where β2 = π / V π2is the modulation index of the second dual-band RF signal, V π2 is the second DC bias voltage, J n (·) is the first kind nth order Bessel function, E in (t) is the optical carrier emitted by the laser, and b1(t)cosω3t+b2(t)cosω4t is the second dual-band RF signal.

[0031] Optionally, the first 90° optical mixer outputs a superposition signal of four X-polarized first modulation signals and the first local oscillation light after phase shift:

[0032] Where E x1 、E x2 、E x3 、E x4 are respectively the superposition signals of the four-way X-polarized first modulation signals output by the first 90° optical mixer and the first local oscillator light after phase shift, E x is the separated X-polarized first modulation signal, E LO It is the first local oscillation light;

[0033] The superposition signal of the second modulation signal with four Y polarizations output by the second 90° optical mixer and the second local oscillation light after phase shift is:

[0034] Where E y1 、E y2 、E y3 、E y4 The four Y-polarized second modulation signals output by the second 90° optical mixer and the superposition signals of the second local oscillation light after phase shift, E y is the separated Y-polarized second modulation signal, E LO It is the second local oscillation light.

[0035] Optionally, the first balanced detector group respectively beats the input four X-polarized first modulation signals with the superposition signal of the first local oscillation light to form a first beat signal and a second beat signal, respectively:

[0036] X R ∝4{a1(t)[-sin(ω1-ω LO )t]+a2(t)sin(ω LO -ω2)t},

[0037] X I ∝4[a1(t)cos(ω1-ω LO )t+a2(t)cos(ω LO -ω2)t];

[0038] The second balanced detector group converts the input four-way Y-polarized second modulation signal and the superposition signal of the second local oscillation light into a third beat frequency signal and a fourth beat frequency signal respectively:

[0039] Y R ∝4{b1(t)[-sin(ω3-ω LO )t]+b2(t)sin(ω LO -ω4)t},

[0040] Y I ∝4[b1(t)cos(ω3-ω LO )t+b2(t)cos(ω LO -ω4)t].

[0041] Optionally, the first 90° electrical mixer is used to perform channel separation on the first beat frequency signal and the second beat frequency signal to obtain the first signal and the second signal respectively:

[0042] a1=X I +X Q∠π / 2 =-8·a1(t)sin(ω1-ω LO )t,

[0043] a2=X I∠π / 2 +X Q =8·a2(t)cos(ω LO -ω2)t;

[0044] The second 90° electrical mixer is used to perform channel separation on the third beat frequency signal and the four beat frequency signals to obtain the third signal and the fourth signal respectively:

[0045] b1=Y I +Y Q∠π / 2 =-8·b1(t)sin(ω3-ω LO )t,

[0046] b2=Y I∠π / 2 +Y Q =8·b2(t)cos(ω LO -ω4)t.

[0047] From the above description, it can be seen that the dual-band RF signal channelization system provided by the present application realizes the separate transmission of the two-way dual-band RF signals by modulating the two-way dual-band RF signals to the two polarization states of the optical carrier through the polarization modulation-dual-drive Mach-Zehnder modulator, thereby improving the utilization efficiency of the single optical carrier link. At the same time, the local oscillator light is used in the polarization phase diversity coherent receiver to confirm the cutting point of the two-way dual-band RF signals, and complete the photoelectric conversion, while suppressing the harmonic components such as RF leakage and mixed spurious, and finally, the channelization cutting is completed through the first 90° electrical mixer and the second 90° electrical mixer, so as to realize the four-way split signal output of the two-way dual-band RF signals and complete the signal separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 This is a schematic diagram of the structure of an embodiment of the present application;

[0050] Figure 2 This is a schematic diagram of the first dual-band radio frequency signal in an embodiment of the present application;

[0051] Figure 3a-3d A schematic diagram of a superposition signal of four X-polarized first modulation signals output by the first 90° optical mixer and the first local oscillation light after phase shift in an embodiment of the present application;

[0052] Figure 4a This is a schematic diagram of the first beat frequency signal in an embodiment of the present application;

[0053] Figure 4b This is a schematic diagram of the first beat frequency signal after being deflected by the first 90° electrical mixer in the embodiment of the present application;

[0054] Figure 4c This is a schematic diagram of the second beat frequency signal in the embodiment of the present application;

[0055] Figure 4d This is a schematic diagram of the second beat frequency signal after being deflected by the first 90° electrical mixer in the embodiment of the present application;

[0056] Figure 5a This is a schematic diagram of a first signal output by a first 90° electrical mixer according to an embodiment of the present application;

[0057] Figure 5b This is a schematic diagram of a second signal output by a first 90° electrical mixer according to an embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0059] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0060] refer to Figure 1A dual-band radio frequency signal channelization system includes a polarization modulation-dual-drive Mach-Zehnder modulator 1, a polarization controller 5, a polarization phase diversity coherent receiver 2, a first electrical 90° mixer and a second electrical 90° mixer. In this case, for two dual-band radio frequency signals with a close interval, if the signals are to be separated, the two dual-band radio frequency signals need to be channelized. Here, the two radio frequency signals are first modulated, the first dual-band radio frequency signal is loaded onto a first optical carrier of X polarization to form a first modulated signal of X polarization, the second dual-band radio frequency signal is loaded onto a second optical carrier of X polarization to form a second modulated signal of X polarization, and the second modulated signal of X polarization is polarized by 90° rotation to form a second modulated signal of Y polarization; and the first signal and the second signal carried by the first dual-band radio frequency signal and the second dual-band radio frequency signal are polarized by 90° rotation to form a second modulated signal of Y polarization. The third signal and the fourth signal carried in the signal are implemented here as two polarization states of the optical carrier as the medium, and the same link realizes the transmission of dual-band information. In order to realize the separate output of the first signal, the second signal, the third signal, and the fourth signal, it is necessary to demodulate the first modulation signal of X polarization and the second modulation signal of Y polarization. The total modulation signal formed by combining the first modulation signal of X polarization and the second modulation signal of Y polarization is input into the polarization phase diversity coherent receiver 2 through the polarization controller 5. The polarization phase diversity coherent receiver 2 is used to realize the beat frequency of the local oscillator light and the separated first modulation signal of X polarization and the separated second modulation signal of Y polarization to realize the photoelectric conversion. Finally, the first 90° electrical mixer 3 is used to realize the channelization separation of the first signal and the second signal, and the second 90° electrical mixer is used to realize the channelization separation of the third signal and the fourth signal.

[0061] In an optional embodiment, the polarization modulation-dual-drive Mach-Zehnder modulator 1 includes an optical coupler 11, a first sub-Mach-Zehnder modulator 12, a second sub-Mach-Zehnder modulator 13, a 90° polarization rotator 14 and a polarization combiner 15, and also includes a first laser 6. The first laser 6 is used to provide an optical carrier. The optical carrier passes through the coupler to divide the optical carrier into two optical carriers, namely the first optical carrier and the second optical carrier. It can be understood that the first optical carrier and the second optical carrier are the same. There is a sub-Mach-Zehnder modulator on each of the upper and lower arms of the polarization modulation-dual-drive Mach-Zehnder modulator 1, namely the first sub-Mach-Zehnder modulator 12 and the second sub-Mach-Zehnder modulator 13. The first sub-Mach-Zehnder modulator 12 modulates the first optical carrier into a first optical carrier with X polarization. The first dual-band RF signal carries the first signal and the second signal through the first The two RF signal input ports of the sub-Mach-Zehnder modulator 12 are modulated onto the first optical carrier with X polarization to output the first modulated signal with X polarization. The second sub-Mach-Zehnder modulator 13 modulates the second optical carrier into the second optical carrier with X polarization. The second dual-band RF signal carrying the third signal and the fourth signal is modulated onto the second optical carrier with X polarization through the two RF signal input ports of the second sub-Mach-Zehnder modulator 14 to output the second modulated signal with X polarization. The 90° polarization rotator 14 performs a 90° polarization rotation on the output second modulated signal with X polarization to form a second modulated signal with Y polarization, and outputs the second modulated signal with Y polarization. Here, the two polarization states of the optical carrier are used as media, and the same link realizes the separate transmission of two dual-band signals, thereby improving the utilization efficiency of a single optical carrier link. Then, the polarization combiner 15 is used to combine the first modulated signal and the second modulated signal.

[0062] In an optional implementation, a first DC polarization voltage is input to a DC bias voltage input port of the first sub-Mach-Zehnder modulator 12, and a second DC bias voltage is input to a DC bias voltage input port of the second sub-Mach-Zehnder modulator 13. Both the first sub-Mach-Zehnder modulator 12 and the second sub-Mach-Zehnder modulator 13 operate at a minimum bias point to achieve suppressed carrier double-sideband modulation.

[0063] In an alternative embodiment, if Figure 2 As shown, suppose the optical carrier emitted by the laser is where ω c is the frequency of the optical carrier emitted by the laser, the waveforms of the first signal and the second signal carried by the first dual-band RF signal input by the first sub-Mach-Zehnder modulator 12 are a1(t) and a2(t), the center frequencies are ω1 and ω2, and the bandwidths are B a1 , B a2The waveforms of the third signal and the fourth signal carried by the second dual-band RF signal input by the second sub-Mach-Zehnder modulator 13 are a3(t) and a4(t), respectively, the center frequencies are ω3 and ω4, respectively, and the bandwidths are B b1 , B b2 , then the first dual-band modulation signal is a1(t)cosω1t+a2(t)cosω2t, and the second dual-band modulation signal is b1(t)cosω3t+b2(t)cosω4t. Then the first modulation signal of X polarization output after modulation by the first sub-Mach-Zehnder modulator 12 is:

[0064]

[0065] Where β1=π / V π1 is the modulation index of the first dual-band RF signal, V π1 is the first DC bias voltage, J n (·) is the first kind nth order Bessel function, E in (t) is the optical carrier emitted by the laser; and after being modulated by the second sub-Mach-Zehnder modulator 13, the second modulated signal of Y polarization output by the 90° polarization rotator 14 is:

[0066]

[0067] Where β2 = π / V π2 is the modulation index of the second dual-band RF signal, V π2 is the second DC bias voltage, J n (·) is the first kind nth order Bessel function, E in (t) is the optical carrier emitted by the laser.

[0068] In an optional embodiment, the polarization controller 5 is connected between the polarization combiner 15 and the first polarization beam splitter 21. The polarization controller 5 adjusts the polarization state of the total modulation signal so that the X polarization state of the total modulation signal is aligned with the main axis of the first polarization beam splitter 21, so as to facilitate the subsequent depolarization of the total modulation signal.

[0069] In an optional implementation, the polarization phase diversity coherent receiver includes a first polarization beam splitter 21, a second polarization beam splitter 22, a first optical 90° mixer, a second optical 90° mixer, a first balanced detector group, and a second balanced detector group. The first polarization beam splitter 21 uses X polarization and Y polarization to separate the first modulated signal of X polarization and the second modulated signal of Y polarization respectively, and uses the second laser 7 to provide a preset local oscillator light to the second polarization beam splitter 22: Among them, ω LO is the frequency of the preset local oscillator light, and the frequency of the preset local oscillator light satisfies

[0070] The second polarization beam splitter 22 splits the preset local oscillation light to form the same first local oscillation light and the second local oscillation light. The separated X-polarized first modulation signal and the first local oscillation light are input to the two input ports of the first 90° optical mixer 23. The separated Y-polarized second modulation signal and the second local oscillation light are input to the two input ports of the second 90° optical mixer 24. In the first 90° optical mixer 23, the phase of the first local oscillation light is first shifted by 0°, 90°, 180° and 270°. The separated X-polarized first modulation signal is superimposed on the four-path phase-shifted first local oscillation light, and the superimposed signals of the four-path X-polarized first modulation signal and the first local oscillation light are output, as shown in FIG. Figure 3a-3d As shown, that is:

[0071] Among them, E x1 、E x2 、E x3 、E x4 The first 90° optical mixer 23 outputs four X-polarized first modulation signals and the superposition signals of the first local oscillation light after phase shift, E x is the separated X-polarized first modulation signal, E LO To preset the local oscillator light signal, the four-way separated X-polarized first modulated signal and the superimposed signal of the first local oscillator light after phase shift are input into the first balanced detector group. Here, it should be noted that the first balanced detector group includes two balanced detectors (BPD), namely the first balanced detector 25 (BPD1) and the second balanced detector 26 (BPD2). Figure 4a-4dIn the two balanced detectors, the second signal carried in the first modulated signal of X polarization in the superimposed signal beats with the local oscillator light signal of X polarization after phase shift to form an intermediate frequency signal (IF1), and the first signal carried in the first modulated signal of X polarization in the superimposed signal beats with the local oscillator light signal of X polarization after phase shift to form an intermediate frequency signal (IF2). In the first beat signal output from BPD1, IF1 and IF2 are in phase, both with a phase of 0°, and in the second beat signal output from BPD2, the phase of IF1 is -90°, and the phase of IF2 is 90°, and then the first beat signal and the second beat signal are input into the first 90° electrical mixer 3. Similarly, the second balanced detector 26 group includes two balanced detectors (BPD), namely, the third balanced detector 27 (BPD3) and the fourth balanced detector 28 (BPD4). In BPD3 and BPD4, the fourth signal carried by the second modulated signal of Y polarization in the superimposed signal beats with the local oscillator light signal of Y polarization after phase shift to form an intermediate frequency signal (IF3), and the third signal carried by the first modulated signal of Y polarization in the superimposed signal beats with the local oscillator light signal of Y polarization after phase shift to form an intermediate frequency signal (IF4). In the third beat signal output from PD3, IF3 and IF4 are in phase, both of which are 0°, while in the fourth beat signal output from BPD4, the phase of IF3 is -90°, while the phase of IF4 is 90°. It should be noted that interference such as harmonic components can be eliminated by the first balanced detector 25 group and the second balanced detector 26 group, and then the third beat signal and the fourth beat signal are input to the second 90° electrical mixer 4; the first beat signal and the second beat signal output from the first 90° optical mixer 23 are respectively:

[0072] X R ∝4{a1(t)[-sin(ω1-ω LO )t}+a2(t)sin(ω LO -ω2)t},

[0073] X I ∝4[a1(t)cos(ω1-ω LO )t+a2(t)cos(ω LO -ω2)t].

[0074] The third beat frequency signal and the fourth beat frequency signal output by the second 90° optical mixer 24 are respectively:

[0075] Y R ∝4{b1(t)[-sin(ω3-ω LO )t]+b2(t)sin(ω LO -ω4)t},

[0076] Y I∝4[b1(t)cos(ω3-ω LO )t+b2(t)cos(ω LO -ω4)t].

[0077] refer to Figure 5a and Figure 5b As shown, in the first output port of the first 90° electrical mixer 3, the first beat frequency signal is first phase-shifted by 90°, and then coupled with the second beat frequency signal, so that the IF1 phases of the first beat frequency signal and the second beat frequency signal are opposite (90°, -90°), and cancellation is achieved. The IF2 phases of the first beat frequency signal and the second beat frequency signal are both 90°, and finally the IF2 signal with doubled power is output, that is, the intermediate frequency signal carrying the first signal. In the second output port of the first 90° electrical mixer 3, the second beat frequency signal is now phase-shifted by 90°, and then coupled with the first beat frequency signal, so that the IF1 phases of the first beat frequency signal and the second beat frequency signal are both 0°, and the IF2 phases of the first beat frequency signal and the second beat frequency signal are opposite (0°, 180°), and cancellation is achieved. Finally, the IF1 signal with doubled power is output, that is, the intermediate frequency signal carrying the second signal, and the channel separation of the first signal and the second signal is achieved. The output first signal and the second signal are respectively:

[0078] a1=X I +X Q∠π / 2 =-8·a1(t)sin(ω1-ω LO )t,

[0079] a2=X I∠π / 2 +X Q =8·a2(t)cos(ω LO -ω2)t;

[0080] Similarly, in the third output port of the second 90° electrical mixer 4, the third beat frequency signal is first phase-shifted by 90° and then coupled with the fourth beat frequency signal. Then, the IF3 phases of the third beat frequency signal and the fourth beat frequency signal are opposite (90°, -90°), and cancellation is achieved. The IF4 phases of the third beat frequency signal and the fourth beat frequency signal are both 90°. Finally, the IF4 signal with doubled power is output, that is, the intermediate frequency signal carrying the third signal. In the fourth output port of the second 90° electrical mixer 4, the fourth beat frequency signal is now phase-shifted by 90° and then coupled with the third beat frequency signal. Then, the IF3 phases of the first beat frequency signal and the second beat frequency signal are both 0°. The IF4 phases of the first beat frequency signal and the second beat frequency signal are opposite (0°, 180°), and cancellation is achieved. Finally, the IF3 signal with doubled power is output, that is, the intermediate frequency signal carrying the fourth signal. The output first signal and the second signal are respectively:

[0081] b1=YI +Y Q∠π / 2 =-8·b1(t)sin(ω3-ω LO )t,

[0082] b2=Y I∠π / 2 +Y Q =8·b2(t)cos(ω LO -ω4)t.

[0083] So far, the system has completed the channel separation of the first signal, the second signal, the third signal and the fourth signal.

[0084] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0085] Although the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0086] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A dual-band radio frequency signal channelization system, characterized in that: It includes a polarization modulation-dual-drive Mach-Zehnder modulator, a polarization phase diversity coherent receiver, a first 90° electrical mixer, a second 90° electrical mixer and a polarization controller; The polarization modulation-dual-drive Mach-Zehnder modulator is used to divide the optical carrier emitted by the laser into a first optical carrier of X polarization and a second optical carrier of X polarization, and load the first dual-band radio frequency signal connected to the first optical carrier of X polarization to form a first modulated signal of X polarization, and load the second dual-band radio frequency signal connected to the second optical carrier of X polarization to form a second modulated signal of X polarization; at the same time, the second modulated signal of X polarization is polarized by 90° to form a second modulated signal of Y polarization; the polarization modulation-dual-drive Mach-Zehnder modulator is also used to combine the first modulated signal of X polarization and the second modulated signal of Y polarization to output a total modulated signal; wherein the first dual-band radio frequency signal carries a first signal and a second signal, and the second dual-band radio frequency signal carries a third signal and a fourth signal; The polarization controller is used to input the total modulated signal into the polarization phase diversity coherent receiver; The polarization phase diversity coherent receiver is used to beat the total modulated signal with a preset local oscillator light, and perform photoelectric conversion to output a first beat signal, a second beat signal, a third beat signal and a fourth beat signal; The first 90° electrical mixer is used to perform channel separation on the first beat frequency signal and the second beat frequency signal to obtain the first signal and the second signal, and the second 90° electrical mixer is used to perform channel separation on the third beat frequency signal and the fourth beat frequency signal to obtain the third signal and the fourth signal.

2. The dual-band radio frequency signal channelization system according to claim 1, characterized in that: The polarization modulation-dual-drive Mach-Zehnder modulator comprises an optical coupler, a first sub-Mach-Zehnder modulator, a second sub-Mach-Zehnder modulator, a 90° polarization rotator and a polarization beam combiner; The optical coupler is used to divide the optical carrier into a first optical carrier and a second optical carrier, wherein the first optical carrier and the second optical carrier are the same; The first sub-Mach-Zehnder modulator is used to modulate the first optical carrier into the first optical carrier of the X polarization, and modulate the first signal and the second signal carried by the first dual-band broadband radio frequency signal onto the first optical carrier of the X polarization respectively, and output the first modulated signal of the X polarization; The second sub-Mach-Zehnder modulator is used to modulate the second optical carrier into the second optical carrier of the X polarization, and modulate the third signal and the fourth signal carried by the second dual-band broadband radio frequency signal onto the second optical carrier of the X polarization respectively, and output the second modulated signal of the X polarization; the 90° polarization rotator performs a 90° polarization rotation on the second modulated signal of the X polarization and outputs a second modulated signal of the Y polarization; The polarization beam combiner is used to combine the X-polarized first modulation signal and the Y-polarized second modulation signal into the total modulation signal.

3. The dual-band radio frequency signal channelization system according to claim 2, characterized in that: The polarization phase diversity coherent receiver comprises a first polarization beam splitter, a second polarization beam splitter, a first 90° optical mixer, a second 90° optical mixer, a first balanced detector group and a second balanced detector group; The first polarization beam splitter uses X polarization and Y polarization to separate the first modulation signal of X polarization and the second modulation signal of Y polarization respectively, and inputs the separated first modulation signal of X polarization and the separated second modulation signal of Y polarization into the first 90° optical mixer and the second 90° optical mixer respectively; The second polarization beam splitter is used to split the preset local oscillation light into a first local oscillation light and a second local oscillation light, and input the first local oscillation light and the second local oscillation light into a first 90° optical mixer and a second 90° optical mixer respectively, wherein the first local oscillation light and the second local oscillation light are the same; The first 90° optical mixer is used to phase shift the first local oscillator light, and superimpose it with the separated X-polarized first modulation signal, output a superimposed signal of four X-polarized first modulation signals and the phase-shifted first local oscillator light, and input it into a first balanced detector group; The second 90° optical mixer is used to phase shift the second local oscillator light, and superimpose it with the separated Y-polarized second modulation signal, output four-way Y-polarized second modulation signal and the superimposed signal of the second local oscillator light, and input it into the second balanced detector group; The first balanced detector group respectively beats the four input X-polarized first modulation signals with the superimposed signal of the first local oscillation light to form a first beat signal and a second beat signal; the second balanced detector group respectively beats the four input Y-polarized second modulation signals with the superimposed signal of the second local oscillation light to convert them into a third beat signal and a fourth beat signal.

4. The dual-band radio frequency signal channelization system according to claim 3, characterized in that: The polarization controller is connected between the polarization beam combiner and the first polarization beam splitter, and is further used to control the X polarization state of the total modulated signal to be aligned with the main axis of the first polarization beam splitter, so as to depolarize the total modulated signal.

5. The dual-band radio frequency signal channelization system according to claim 3, characterized in that: The first signal and the second signal waveforms are a1(t) and a2(t) respectively, the center frequencies are ω1 and ω2 respectively, and the bandwidths are B a1 , B a2 The waveforms of the third signal and the fourth signal are a3(t) and a4(t), the center frequencies are ω3 and ω4, and the bandwidths are B b1 , B b2 , the optical carrier frequency is ω c , the preset local oscillator frequency is ω LO , which satisfies 6. The dual-band radio frequency signal channelization system according to claim 3, characterized in that: A first DC bias voltage is input to the DC bias voltage input port of the first sub-Mach-Zehnder, so that the first sub-Mach-Zehnder modulator operates at a minimum bias point, and carrier suppressed double-sideband modulation is realized, so that the first dual-band radio frequency signal is modulated onto the first optical carrier of X polarization and the first modulated signal of X polarization is output; a second DC bias voltage is input to the DC bias voltage input port of the second sub-Mach-Zehnder, so that the second sub-Mach-Zehnder modulator operates at a minimum bias point, and carrier suppressed double-sideband modulation is realized, so that the second dual-band radio frequency signal is modulated onto the second optical carrier of X polarization and the second modulated signal of X polarization is output.

7. The dual-band radio frequency signal channelization system according to claim 5, characterized in that: The first modulated signal output of the X polarization is: Where β1=π / V π1 is the modulation index of the first dual-band RF signal, V π1 is the first DC bias voltage, J n (·) is the first-order Bessel function of the first kind, Ein(t) is the optical carrier emitted by the laser, and a1(t)cosω1t+a2(t)cosω2t is the first dual-band RF signal; The second modulated signal output of the Y polarization is: Where β2 = π / V π2 is the modulation index of the second dual-band RF signal, V π2 is the second DC bias voltage, J n (·) is the first kind nth order Bessel function, Ein(t) is the optical carrier emitted by the laser, and b1(t)cosω3t+b2(t)cosω4t is the second dual-band RF signal.

8. The dual-band radio frequency signal channelization system according to claim 7, characterized in that: The first 90° optical mixer outputs a superposition signal of four X-polarized first modulation signals and the first local oscillator light after phase shift: Where E x1 、E x2 、E x3 、E x4 are respectively the superposition signals of the four-way X-polarized first modulation signals output by the first 90° optical mixer and the first local oscillator light after phase shift, E x is the separated X-polarized first modulation signal, E LO It is the first local oscillation light; The superposition signal of the second modulation signal with four Y polarizations output by the second 90° optical mixer and the second local oscillation light after phase shift is: Where E y1 、E y2 、E y3 、E y4 The four Y-polarized second modulation signals output by the second 90° optical mixer and the superposition signals of the second local oscillation light after phase shift, E y is the separated Y-polarized second modulation signal, E LO It is the second local oscillation light.

9. The dual-band radio frequency signal channelization system according to claim 8, characterized in that: The first balanced detector group respectively beats the input four X-polarized first modulation signals with the superposition signal of the first local oscillation light to form a first beat signal and a second beat signal, respectively: X R ∝4{a1(t)[-sin(ω1-ω LO )t]+a2(t)sin(ω LO -ω2)t}, X I ∝4[a1(t)cos(ω1-ω LO )t+a2(t)cos(ω LO -ω2)t]; The second balanced detector group converts the input four-way Y-polarized second modulation signal and the superposition signal of the second local oscillation light into a third beat frequency signal and a fourth beat frequency signal respectively: Y R ∝4{b1(t)[-sin(ω3-ω LO )t]+b2(t)sin(ω LO -ω4)t}, Y I ∝4[b1(t)cos(ω3-ω LO )t+b2(t)cos(ω LO -ω4)t]。 10. The dual-band radio frequency signal channelization system according to claim 9, characterized in that: The first 90° electrical mixer is used to perform channel separation on the first beat frequency signal and the second beat frequency signal to obtain the first signal and the second signal respectively: a1=X I +X Q∠ π2=-8·a1(t)sin(ω1-ω LO )t, a2=X I∠ π2+X Q =8·a2(t)cos(ω LO -ω2)t; The second 90° electrical mixer is used to perform channel separation on the third beat frequency signal and the four beat frequency signals to obtain the third signal and the fourth signal respectively: b1=Y I +Y Q∠ π2=-8·b1(t)sin(ω3-ω LO )t, b2=Y I∠ π2+Y Q =8·b2(t)cos(ω LO -ω4)t。

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