Dual-band dual-output microwave photonic up-conversion mixer

Abstract

This invention provides a dual-band, dual-output microwave photonic up-conversion mixer. The intermediate frequency (IF) signal and the local oscillator (LO) signal are modulated onto the light wave emitted by a laser via a polarization-multiplexed dual parallel Mach-Zehnder modulator (PDM-DPMZM), generating a polarization-multiplexed optical signal. This signal is split into two paths by an optical power beamsplitter (OPS). The two paths are then controlled by a modulation optical path consisting of a polarization controller (PC) and a polarization beamsplitter (PBS), which adjusts the phase between the two optical frequency components and linearly combines and splits the polarization components, introducing a 90° relative phase shift between the sidebands of the two optical signals. After photoelectric conversion by two balanced detectors (BPD), I / Q quadrature mixing is achieved. The resulting photocurrents each contain two up-converted frequency signals but with different relative phases. A 2×2 90° bridge (HC2) is used to phase-shift and couple the two up-converted frequency signals, achieving coherent constructive and destructive superposition of the two up-converted frequency signals, thereby realizing the separate output of the dual-band up-converted signals.

Description

Technical Field

[0001] This invention relates to the field of optical communication, and more particularly to the problem of microwave photonic signal processing in optical communication. Background Technology

[0002] Microwave frequency conversion technology is widely used in wireless communication, satellite relay, radar systems, electronic warfare, and other scenarios. The process of converting a low-frequency intermediate frequency (IF) signal to a higher-frequency radio frequency (RF) signal is called frequency up-conversion; the process of converting a high-frequency RF signal to a low-frequency IF signal is called frequency down-conversion. With the rapid development of communication technology, mixers need to have higher conversion gain, larger dynamic range, and more effective spurious suppression capabilities. Due to the speed bottleneck of electronic devices, the performance of traditional electrical mixers has faced significant challenges. In recent years, microwave photonics technology has received widespread attention and has been applied to microwave frequency conversion. Compared with traditional electrical frequency conversion methods, microwave photonics frequency conversion has many advantages, such as large bandwidth, high isolation, and resistance to electromagnetic interference. Numerous microwave photonics frequency conversion methods based on different design structures have been proposed. Currently, there are two main methods for realizing microwave photonics frequency conversion: microwave photonics frequency conversion methods based on nonlinear effects and microwave photonics frequency conversion methods based on electro-optic modulation.

[0003] Microwave photonic frequency conversion methods based on nonlinear effects mainly utilize the stimulated Brillouin scattering (SBS) effect of the medium on light. The SBS effect generates a frequency shift, which is used as the local oscillator signal of the mixer. The input useful signal is then loaded onto an electro-optic modulator and simultaneously fed into a photodetector along with the local oscillator signal for beat frequency conversion, ultimately yielding an up-converted or down-converted radio frequency (RF) signal. However, for silicon media, the SBS shift is typically between 10-11 GHz, which limits the frequency tuning range and makes wide-range tuning difficult. Another problem is that the magnitude of the SBS shift is easily affected by environmental factors such as temperature and pressure, leading to unstable signal frequencies.

[0004] One commonly used method is the microwave photonic frequency conversion method based on electro-optic modulation. The local oscillator signal and the radio frequency signal are modulated onto the optical wave using an electro-optic modulator, signal processing is performed in the optical domain, and finally, the up-converted or down-converted signal is obtained by beat frequency analysis using a photodetector. This method can increase the frequency adjustment range, is less affected by external physical factors, and has relatively stable performance. Summary of the Invention

[0005] This invention proposes a dual-band, dual-output microwave photonic up-conversion mixer. The intermediate frequency (IF) signal and the local oscillator (LO) signal are modulated onto the light wave emitted by a laser via a polarization-multiplexed dual parallel Mach-Zehnder modulator (PDM-DPMZM), generating a polarization-multiplexed optical signal. This signal is split into two paths by an optical power beamsplitter (OPS). Each path then undergoes a control optical path composed of a polarization controller (PC) and a polarization beamsplitter (PBS) to adjust the phase between the optical frequency components and linearly combine and split the polarization components, introducing a 90° relative phase shift between the sidebands of the two optical signals. After photoelectric conversion by two balanced detectors (BPD), I / Q quadrature mixing is achieved. The resulting photocurrents each contain two up-converted frequency signals with different relative phases. A 2×2 90° bridge (HC2) is used to phase shift and couple the two up-converted frequency signals, achieving coherent constructive and destructive superposition of the two up-converted frequency signals, thus realizing the separate output of the dual-band up-converted signals. It includes:

[0006] As a preferred method, a continuous wave laser (CW LD) emits an angular frequency of ω. C Linearly polarized light waves have constant photoelectric field amplitude and frequency, and stable polarization direction and phase.

[0007] As a preferred method, in the PDM-DPMZM, the injected linearly polarized light wave is split into X and Y paths with equal power and injected into the X-DPMZM and Y-DPMZM respectively. By adjusting the DC bias voltage of the X-DPMZM, both sub-modulators of the X-DPMZM operate at the minimum bias point, and the main modulator operates at the quadrature bias point. The intermediate frequency signal IF is applied to the RF electrodes of the two sub-MZMs of the X-DPMZM via a 90° bridge HC1 to perform carrier-suppressed single-sideband modulation on the X-path light wave, generating a signal containing only angular frequency ω. C +ω IF The linearly polarized optical signal is modulated by IF. By adjusting the DC bias voltage of the Y-DPMZM, the sub-modulator MZM-c of the Y-DPMZM operates at its maximum transmission point. The DC bias of the sub-modulator MZM-d is set to an appropriate value so that the output light wave has the same amplitude and opposite phase as the optical carrier output by MZM-c. The bias voltage of the main modulator is zero, and the local oscillator signal LO is only applied to the RF electrode of the sub-MZM-c of the Y-DPMZM. The Y-path light wave is modulated by the Y-DPMZM to generate a signal containing ω. C +2ω LO and ω C -2ω LO Two linearly polarized light waves with LO modulation and two optical frequency components are rotated 90° by an optical polarization rotator and then orthogonally combined with an IF-modulated linearly polarized light signal, resulting in an output containing an angular frequency of ω. C +ω IF ω C +2ω LO and ωC -2ω LO A polarization-multiplexed optical signal with three optical frequency components.

[0008] As a preferred method, the optical power beam splitter (OPS) has a splitting ratio of 1:1 and is insensitive to the frequency and polarization of the light wave. It splits the polarization-multiplexed optical signal output by the PDM-DPMZM into two paths, I and Q, with equal power.

[0009] As a preferred method, in two control optical paths composed of a polarization controller (PC) and a polarization beam splitter (PBS), one control optical path rotates the polarization of the I-path light wave through the PC, so that the polarization directions of the orthogonal LO-modulated linearly polarized light wave and the IF-modulated linearly polarized light signal in the polarization multiplexed optical signal are at 45° to the transmission principal axis of the PBS. This achieves equal-power, out-of-phase projection of the two orthogonal components onto the output axis of the PBS, thereby realizing a linear combination of the LO-modulated linearly polarized light wave and the IF-modulated linearly polarized light signal, producing two paths, each containing an angular frequency of ω. C +ω IF ω C +2ω LO and ω C -2ω LO The three optical frequency components have the same polarization direction, but the three optical frequency components of the two optical signals are orthogonal in phase. The other control optical path also rotates the polarization of the Q-path light wave through the PC, so that the orthogonal LO-modulated linearly polarized light wave and IF-modulated linearly polarized light signal are projected onto the output axis of the PBS with equal power and out of phase, realizing the linear combination of LO-modulated linearly polarized light wave and IF-modulated linearly polarized light wave. However, the PC of the two control optical paths makes the three optical frequency components of the two pairs of linearly polarized light signals output by the I and Q paths have different relative phases, and the relative phase of the I and Q light waves is 90°.

[0010] As a preferred method, the two optically balanced detectors (BPDs) are each composed of two symmetrical photodetectors and differential amplifier circuits, possessing identical performance parameters and sufficient response bandwidth. The four optical signals output from the two photodetectors (PBSs) are injected into the two BPDs respectively, performing square-law detection and differential superposition. The output photocurrents of both BPDs contain 2ω. LO +ω IF and 2ω LO -ω IF Two radio frequency signals that are converted at different frequencies, but their phases are orthogonal.

[0011] As a preferred method, in the two 2×2 90° microwave bridges HC, the first 90° microwave bridge HC1 is used to split the intermediate frequency (IF) signal input from the port into two orthogonal signals of equal power, enabling X-DPMZM to achieve carrier-suppressed single-sideband modulation of the optical wave; the second bridge HC2 will contain 2ω LO +ωIF and 2ω LO -ω IF However, the phase-orthogonal I-channel and Q-channel signals are spun out and coupled with equal power and orthogonal paths, resulting in the signals from the I-channel and Q-channel having an angular frequency of 2ω. LO +ω IF and 2ω LO -ω IF The phase relationship between the two radio frequency components is transformed from quadrature to in-phase and out-of-phase, and then in-phase components are superimposed and out-of-phase components are destructively superimposed at the output of HC2, respectively, to achieve 2ω of the two radio frequency components. LO +ω IF and 2ω LO -ω IF Separate and output from different ports of HC2.

[0012] As a preferred method, the present invention provides a dual-band dual-output microwave photonic upconversion mixer structure, the components required to realize the function including:

[0013] A continuous wave laser (CW LD) is used to generate an optical carrier.

[0014] A polarization-multiplexed dual parallel Mach-Zehnder modulator (PDM-DPMZM) is used to modulate the IF and LO signals onto an optical wave in parallel and perform polarization rotation and polarization orthogonal coupling.

[0015] An optical power beam splitter (OPS) is used to split the optical carrier generated by the laser into two paths, I and Q, and is insensitive to the frequency and polarization of the optical wave.

[0016] Two polarization controllers (PCs) are used to change the polarization direction and the relative phase of the polarization multiplexed signal;

[0017] Two polarization beam splitters (PBSs) are used to polarize and linearly combine polarization multiplexed optical signals that have been polarized inversely adjusted and introduced with relative phase in two polarization directions, to construct a pair of linearly polarized optical signals containing three optical frequency components. The amplitudes of these three polarization components are equal and they have a specific phase relationship.

[0018] Two optical balance detection circuits (BPDs) are used to perform optical balance detection on the four optical signals output from the two PBSs, generating two up-converted radio frequency (RF) signals respectively, and the phases of each RF signal output by the two BPDs are orthogonal.

[0019] Two 2×2 90° microwave bridges are used to couple the radio frequency photocurrents output by the two BPDs. At the same time, a 90° relative phase shift is introduced at the two output ports, so that the phase of the radio frequency signal at the same output port is converted to in-phase or out-of-phase. The conversion components at the two frequencies are coherently superimposed, thereby realizing the separation and separate output of the two. Attached Figure Description

[0020] Figure 1 The present invention provides a block diagram of a dual-band dual-output microwave photonic mixer capable of upconversion and a spectral or frequency spectrum diagram of points (a) to (j) in the block diagram.

[0021] Figure 2 The spectrum output by X-DPMZM;

[0022] Figure 3 The spectrum output by Y-DPMZM;

[0023] Figure 4 The spectrum output by PDM-DPMZM;

[0024] Figure 5 The spectrum diagram of the balanced detector I-channel output;

[0025] Figure 6 The spectrum diagram of the Q-channel output of the balanced detector;

[0026] Figure 7 The spectrum diagram of the up-converted signal output from bridge output port 1;

[0027] Figure 8 The spectrum diagram of the up-converted signal output from bridge output port 2;

[0028] Figure 9 The spectrum diagram for the frequency adjustability test of the upconversion signal from 8 to 11 GHz;

[0029] Figure 10 The spectrum diagram for the frequency adjustability test of the upconversion signal in the 13-16GHz range;

[0030] Figure 11 This is a spurious-free dynamic range performance test chart. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] Figure 1This invention provides a system principle block diagram and a spectral or frequency spectrum diagram of points (a) to (j) in the block diagram. The invention provides a dual-band dual-output microwave photonic mixing method and system capable of upconversion. The light wave emitted by the laser is injected into a polarization-multiplexed dual parallel Mach-Zehnder modulator (PDM-DPMZM). The optical signal output from the modulator is split into two paths by a power beam splitter (OPS), which are then sent to two control optical paths. Each control optical path consists of a polarization controller (PC) and a polarization beam splitter (PBS). To construct an I / Q orthogonal structure to achieve phase cancellation of unwanted signals, the PC in the lower channel is adjusted to introduce a 90° phase shift. After photoelectric conversion by a balanced detector, I / Q mixing is achieved. The generated photocurrent passes through a 2×2 90° microwave bridge, from which two electrical signals of different frequencies are output from the two channels of the bridge, thereby realizing the dual-band dual-output upconversion function. To achieve the above effect, the following steps are required:

[0033] First, a continuous-wave laser generates an optical carrier with a center carrier frequency of 193.100 THz, a linewidth of 10 MHz, and a power of 19 dBm, expressed as E. in (t)=E0e jωct E0 represents the amplitude of light, ω C This represents the angular frequency of the light. The generated linearly polarized light carrier is injected into an integrated PDM-DPMZM, which consists of an optical power beamsplitter, two parallel sub-DPMZMs (X-DPMZM and Y-DPMZM), a 90° polarization rotator (90°PR), and a polarization beam combiner (PBC). The intermediate frequency (IF) signal is generated by a sine wave generator at a frequency of 2 GHz and a power of 13 dBm. The local oscillator (LO) signal has a frequency of 6 GHz and a power of 19 dBm. The X-DPMZM is used to modulate the IF signal, where the two sub-modulators Xa and Xb operate at the minimum bias point, and the main modulator operates at the quadrature bias point. Assuming the modulator extinction ratio is infinitely large, the linearly polarized light signal output from the X-DPMZM can be expressed as:

[0034]

[0035] In the formula, ω IF Let be the angular frequency of the IF signal. The modulation index β1 of X-DPMZM is πV. IF / V π V IF V represents the amplitude of the IF signal. π This represents the half-wave voltage of the modulator. Since the IF signal power injected into the X-DPMZM is relatively small, the effects of second-order and higher-order sidebands can be ignored. The spectrum of the X-DPMZM output is shown below. Figure 2As shown, the optical carrier rejection ratio can reach 29.0 dB. The Y-DPMZM also contains two sub-modulators, Ya and Yb. Ya operates at the maximum transmission point, generating the optical carrier and positive and negative second-order optical sidebands under the drive of the LO signal; Yb only requires a suitable DC bias voltage V. DC The linearly polarized light signal output from the Y-DPMZM can be expressed as:

[0036]

[0037] In the formula, ω LO Let ω be the angular frequency of the LO signal. In Y-DPMZM, the modulation index β2 = πV is given by β2. LO / Vπ, the modulation index β3 of Yb = πV DC / V π V LO V is the amplitude of the LO signal. DC The amplitude of the DC signal. To suppress the optical carrier in Y-DPMZM, the following conditions must be met:

[0038] J0(β2)=cosβ3

[0039] The DC bias voltage V of the modulator Yb is adjusted. DC This ensures that the optical carrier of the Y-DPMZM is completely suppressed. The output spectrum of the Y-DPMZM at this time is as follows: Figure 3 As shown, the optical carrier rejection ratio reaches 27.8 dB. When the optical carrier is suppressed, the linearly polarized light signal output from the Y-DPMZM can be expressed as...

[0040]

[0041] The Y-polarized light signal, after passing through a 90° polarization rotator, is combined with the X-polarized light signal via a polarization combiner. The expression can be given as follows:

[0042]

[0043] The output spectrum after polarization beam combining is shown below. Figure 4 As shown in the diagram. Subsequently, the optical signal is split into two paths (I-path and Q-path) by an optical power beamsplitter. In each path, the orthogonally polarized multiplexed signal is converted into linearly polarized light after passing through a PC and a PBS. The I-path and Q-path together generate four polarized optical signals, which can be represented as follows:

[0044]

[0045] Where α and β are the polarization angles of the I-path and Q-path PBS, respectively. and The phase difference between the two polarization states introduced by the I-path and Q-path PCs are respectively. To maximize the output optical power, the polarization angles α and β of the PBS are both adjusted to 45°. According to the differential characteristics of the BPD, the electrical signal expressions of the I-path and Q-path outputs after passing through the BPD should be:

[0046]

[0047]

[0048] in The response of BPD. When When the I-path and Q-path are orthogonal, the expression for the output photocurrent is:

[0049]

[0050]

[0051] The photocurrent output spectrum diagrams for I-channel and Q-channel are shown below. Figure 5 and Figure 6 As shown in the spectrum diagram, the signal contains eight different frequency components (2GHz, 4GHz, 8GHz, 10GHz, 12GHz, 14GHz, 22GHz, and 26GHz). The 2GHz signal represents the frequency leakage of the IF signal, and the 12GHz signal represents the frequency leakage of twice the LO signal. The 4GHz and 8GHz signals are respectively ω... LO -ω IF and ω LO +ω IF Frequency leakage, 4 ω at 22 GHz and 4 ω at 26 GHz. LO -ω IF and 4ω LO +ω IF Frequency leakage; 10GHz and 14GHz are 2ω respectively. LO -ω IF and 2ω LO +ω IF Two useful signal frequencies need to be output. The appearance of the above six spurious frequency components is due to the limited extinction ratio of the optical modulator, and their power is at least 30dB lower than the useful signal. The amplitude of the spurious frequency components can be further reduced by increasing the extinction ratio of the optical modulator. After passing through a 2×2 90° microwave bridge, the expression of the two ports of the bridge output is as follows:

[0052]

[0053]

[0054] The output signal spectrum diagrams of bridge output ports 1 and 2 are as follows: Figure 7 and Figure 8 As shown. From Figure 7 It can be seen that the 10GHz frequency has the highest power in output port 1, which is the up-conversion signal required by this scheme, and the unwanted signal spurious rejection ratio can reach 30.6dB. Meanwhile, from... Figure 8 It can be seen that the 14GHz frequency in output port 2 has the highest power, which is the up-conversion signal of the other band required by this scheme, and the unwanted signal spurious rejection ratio can reach 28.1dB. From the above two equations, it can be seen that the two output ports generate two signals of different frequencies, realizing the dual-band dual-output harmonic up-conversion function.

[0055] Frequency tunability testing was then conducted, with the IF signal adjusted from 1GHz to 4GHz in 0.5GHz steps, while the LO signal frequency was maintained at 6GHz. Test results show that this scheme can achieve frequency tunability of the upconversion signal in the range of 8-11GHz (X-band) and 13-16GHz (Ku-band), with spurious signal rejection ratios of 30.6dB and 27.6dB, respectively. The test results are shown in the figure below. Figure 9 and Figure 10 As shown.

[0056] Finally, to verify the linearity of the scheme, the spurious-free dynamic range of the system was measured through simulation. Two-tone signals at 2 GHz and 2.1 GHz were used as the intermediate frequency (IF) signal. The final measured spurious-free dynamic range of the scheme was 96.8 dB·Hz. 2 / 3 Test image as follows Figure 11 As shown.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dual-band, dual-output microwave photonic upconversion mixing method, characterized in that: The laser emits an angular frequency of ω C The linearly polarized light wave is injected into the polarization-multiplexed dual parallel Mach-Zehnder optical modulator PDM-DPMZM, and is spun by a 90° microwave bridge HC1 with an angular frequency of ω. IF The intermediate frequency signal and angular frequency are ω LO The local oscillator signal is parallel modulated and orthogonally polarized. The optical signal output from the optical modulator is split into I and Q paths by the optical power beamsplitter (OPS), and sent to two parallel control optical paths. Each control optical path consists of a polarization controller (PC) and a polarization beamsplitter (PBS). To construct the I / Q structure and achieve unwanted signal cancellation, the PC in the two optical paths is adjusted to introduce a 90° relative phase shift between the sidebands of the two optical signals. At the same time, the polarization projection and linear combination of the IF modulated optical signal and the LO modulated optical signal are realized, further splitting into four linearly polarized beams. These beams are then orthogonally mixed and photoelectric converted by two optical balance detectors (BPD). The resulting I and Q path photocurrents both contain an angular frequency of 2ω. LO −ω IF and 2ω LO +ω IF The two up-converted radio frequency signals are orthogonal in phase (I / Q). The resulting photocurrent is phase-shifted and cross-coupled by a 2×2 90° microwave bridge HC2 to achieve coherent superposition. The two up-converted radio frequency signals are separated and output from the two output ports of the 90° microwave bridge HC2, thereby realizing the separation and output of dual-band up-converted radio frequency signals.

2. The method as described in claim 1, characterized in that, The laser is a continuous wave laser (CW LD). The continuous wave laser (CW LD) emits an angular frequency of ω. C Linearly polarized light waves have constant photoelectric field amplitude and frequency, and stable polarization direction and phase.

3. The method according to claim 1, characterized in that, The polarization-multiplexed dual parallel Mach-Zehnder modulator PDM-DPMZM: In the PDM-DPMZM, the injected linearly polarized light wave is split into X and Y paths by equal power and injected into the X-DPMZM and Y-DPMZM respectively. By adjusting the DC bias voltage of the X-DPMZM, both sub-modulators of the X-DPMZM operate at the minimum bias point, and the main modulator operates at the quadrature bias point. The intermediate frequency signal IF is applied to the RF electrodes of the two sub-MZMs of the X-DPMZM via a 90° bridge HC1 to perform carrier-suppressed single-sideband modulation on the X-path light wave, generating a signal containing only angular frequency ω. C +ω IF The linearly polarized optical signal is modulated by IF. By adjusting the DC bias voltage of the Y-DPMZM, the sub-modulator MZM-c of the Y-DPMZM operates at its maximum transmission point. The DC bias of the sub-modulator MZM-d is set to an appropriate value so that the output light wave has the same amplitude and opposite phase as the optical carrier output by MZM-c. The bias voltage of the main modulator is zero, and the local oscillator signal LO is only applied to the RF electrode of the sub-MZM-c of the Y-DPMZM. The Y-path light wave is modulated by the Y-DPMZM to generate a signal containing ω. C +2ω LO and ω C −2ω LO Two linearly polarized light waves with LO modulation and two optical frequency components are rotated 90° by an optical polarization rotator and then orthogonally combined with an IF-modulated linearly polarized light signal, resulting in an output containing an angular frequency of ω. C +ω IF ω C +2ω LO and ω C −2ω LO A polarization-multiplexed optical signal with three optical frequency components.

4. The method according to claim 1, characterized in that, The optical power beam splitter OPS: The splitting ratio is 1:1, and it is insensitive to the frequency and polarization of the light wave. The polarization-multiplexed optical signal output by the PDM-DPMZM is split into two paths, I and Q, with equal power.

5. The method according to claim 1, characterized in that, The two control optical paths, each consisting of a polarization controller (PC) and a polarization beam splitter (PBS), are as follows: A control optical path rotates the polarization of the I-path light wave via a PC, causing the polarization directions of the orthogonal LO-modulated linearly polarized light wave and IF-modulated linearly polarized light signal in the polarization multiplexed optical signal to be at 45° to the transmission principal axis of the PBS. This achieves equal-power, out-of-phase projection of the two orthogonal components onto the output axis of the PBS, thereby realizing a linear combination of the LO-modulated linearly polarized light wave and the IF-modulated linearly polarized light signal, producing two paths, each containing an angular frequency of ω. C +ω IF ω C +2ω LO and ω C −2ω LO The three optical frequency components have the same polarization direction, but the three optical frequency components of the two optical signals are orthogonal in phase. The other control optical path also rotates the polarization of the Q-path light wave through the PC, so that the orthogonal LO-modulated linearly polarized light wave and IF-modulated linearly polarized light signal are projected onto the output axis of the PBS with equal power and out of phase, realizing the linear combination of LO-modulated linearly polarized light wave and IF-modulated linearly polarized light wave. However, the PC of the two control optical paths makes the three optical frequency components of the two pairs of linearly polarized light signals output by the I and Q paths have different relative phases, and the relative phase of the I and Q light waves is 90°.

6. The method according to claim 1, characterized in that, The two optical balance detectors (BPDs): Each device consists of two symmetrical photodetectors and differential amplifier circuits, possessing identical performance parameters and sufficient response bandwidth. Four optical signals output from the two photodetectors (PBS) are injected into the two photobalanced detectors (BPDs) respectively, undergoing square-law detection and differential superposition. The output photocurrents of both devices contain 2ω. LO +ω IF and 2ω LO −ω IF Two radio frequency signals that are converted at different frequencies, but their phases are orthogonal.

7. The method according to claim 1, characterized in that, The two 2×2 90° microwave bridges HC: The first 90° microwave bridge HC1 is used to take the input from the port with an angular frequency of ω IF The intermediate frequency (IF) signal is split into two orthogonal signals of equal power, enabling X-DPMZM to achieve carrier-suppressed single-sideband modulation of light waves; The second 90° microwave bridge HC2 will contain an angular frequency of 2ω. LO +ω IF and 2ω LO −ω IF However, the phase-orthogonal I-channel and Q-channel signals are spun out and coupled with equal power and orthogonal paths, resulting in the signals from the I-channel and Q-channel having an angular frequency of 2ω. LO +ω IF and 2ω LO −ω IF The phase relationship between the two radio frequency components is transformed from quadrature to in-phase and out-of-phase, respectively. Then, at the output of HC2, the in-phase components are superimposed with phase extension and the out-of-phase components are superimposed with phase cancellation, respectively, achieving two angular frequencies of 2ω. LO +ω IF and 2ω LO −ω IF The radio frequency components are separated and output from different ports of HC2.

8. A dual-band dual-output microwave photonic upconversion mixer, characterized in that, It includes: A continuous wave laser (CW LD) is used to generate an optical carrier. A polarization-multiplexed dual parallel Mach-Zehnder modulator (PDM-DPMZM) is used to modulate the IF and LO signals onto an optical wave in parallel and perform polarization rotation and polarization orthogonal coupling. An optical power beam splitter (OPS) is used to split the optical carrier generated by the laser into two paths, I and Q, and is insensitive to the frequency and polarization of the optical wave. Two polarization controllers (PCs) are used to change the polarization direction and the relative phase of the polarization multiplexed signal; Two polarization beam splitters (PBSs) are used to polarize and linearly combine polarization multiplexed optical signals that have been polarized inversely adjusted and introduced with relative phase in two polarization directions, to construct a pair of linearly polarized optical signals containing three optical frequency components. The amplitudes of these three polarization components are equal and they have a specific phase relationship. Two optical balance detection circuits (BPDs) are used to perform optical balance detection on the four optical signals output from the two PBSs, generating two up-converted radio frequency (RF) signals respectively, and the phases of each RF signal output by the two BPDs are orthogonal. Two 2×2 90° microwave bridges HC, one of which is used to split the intermediate frequency (IF) signal into two phase-quadrature signals of equal power, enabling X-DPMZM to achieve carrier-suppressed single-sideband modulation of optical waves; Another method is used to couple the radio frequency photocurrents of the two BPD outputs, while introducing a 90° relative phase shift at the two output ports, so that the phase of the radio frequency signal at the same output port is converted to in-phase or out-of-phase, and the conversion components at the two frequencies are coherently superimposed, thereby realizing the separation and separate output of the two.

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