Nonlinear compensation apparatus, method, and system

Abstract

The application discloses a kind of nonlinear compensation device, method and system, it is related to communication technical field.Nonlinear compensation device includes: mixing frequency module, photoelectric conversion module and processing module.Mixing frequency module is used to convert first, second light beam into two mixing frequency signals being opposite signal each other, and transmission is given to photoelectric conversion module.Photoelectric conversion module is used to convert first mixing frequency signal into first electric signal containing first third-order intermodulation component, and for second mixing frequency signal is converted into second electric signal transmission to processing module.Processing module extracts even-order intermodulation component from second electric signal, and it is superimposed to direct current bias voltage of photoelectric conversion module, so that photoelectric conversion module generates second third-order intermodulation component equal in size and opposite in direction with first third-order intermodulation component in the process of modulating first electric signal, to make that the signal of final output does not contain odd-order intermodulation component.Thereby the nonlinear distortion of output signal is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, in particular to a nonlinear compensation device, method and system. BACKGROUND

[0002] With the rapid development of the fifth generation mobile networks (5G), its frequency band has been expanded to millimeter wave. When transmitting signals, the signals are processed by beamforming, and common beamforming is electric domain beamforming (for example, the output stage device is a power amplifier). The photodetector is a device that can convert optical signals into electrical signals. Compared with electric domain beamforming, microwave photon beamforming with a photodetector as an output stage device has the advantages of super large bandwidth, flexible frequency band, anti-interference, and easy realization of full connection of antenna array. However, as the incident light power increases, the electron concentration in the depletion region of the photodetector increases, and the electric field generated by the electrons is opposite to the internal electric field of the depletion region, thereby weakening the internal electric field. This will cause the moving speed of the photo-generated carriers to decrease, and the output current will not increase linearly with the increase of the incident light power, but a nonlinear output current is generated. Therefore, like electric domain beamforming, microwave photon beamforming also has the problem of nonlinear distortion of the output stage device.

[0003] In the prior art, the method of digital predistortion is usually used to solve the nonlinear distortion problem of the output stage device of the digital channel in electric domain beamforming. However, for a hybrid beamforming architecture including a digital channel and an analog channel, since the number of analog channels is much larger than the number of digital channels, the method of digital predistortion set at the digital channel cannot accurately pre-compensate the output stage device at each analog channel, and the difference between the output stage devices of each analog channel will also affect the digital predistortion. SUMMARY

[0004] The present application provides a nonlinear compensation device, method and system for respectively reducing the in-band and out-of-band distortion in the output signal at each analog channel and improving the linearity of the system.

[0005] The technical solution is as follows:

[0006] In a first aspect, a nonlinear compensation device is provided, which includes a mixing module, an optoelectronic conversion module connected to the mixing module, and a processing module connected to the optoelectronic conversion module. The mixing module is configured to mix a first light beam and a second light beam to obtain a first mixed signal and a second mixed signal, which are reverse signals of each other. The first light beam is a modulated signal, and the second light beam is an unmodulated signal. The optoelectronic conversion module is configured to convert the first mixed signal into a first electrical signal, convert the second mixed signal into a second electrical signal, and transmit the second electrical signal to the processing module. The first electrical signal includes at least a first odd-order intermodulation component. The processing module is configured to extract an even-order intermodulation component meeting a preset requirement from the second electrical signal, and superimpose the even-order intermodulation component on a direct current bias voltage of the optoelectronic conversion module. The optoelectronic conversion module is configured to generate a second odd-order intermodulation component in the process of modulating the first electrical signal according to the direct current bias voltage superimposed with the even-order intermodulation component, and finally obtain a target modulated signal. The target modulated signal does not contain an odd-order intermodulation component, the second odd-order intermodulation component is equal in size and opposite in direction to the first odd-order intermodulation component.

[0007] In a possible implementation of the present application, the nonlinear compensation device is arranged in an analog channel in a hybrid beamforming architecture.

[0008] The nonlinear compensation device provided in the application first performs mixing frequency processing on the first light beam and the second light beam through the mixing frequency module to obtain first mixed frequency signals and second mixed frequency signals which are reverse signals of each other, and then obtains first electric signals and second electric signals from the first mixed frequency signals and the second mixed frequency signals through the photoelectric conversion module. Since the first electric signals include first odd-order intermodulation components, it indicates that there is nonlinear distortion in the first electric signals. Therefore, in order to reduce the nonlinear distortion of the target modulation signals finally output by the photoelectric conversion module, the second electric signals are sent to the processing module, so that the processing module can obtain even-order intermodulation components meeting preset requirements from the second electric signals. The even-order intermodulation components meeting the preset requirements are superimposed on the direct current bias voltage of the photoelectric conversion module. Since the even-order intermodulation components are superimposed on the direct current bias voltage of the photoelectric conversion module, the direct current bias voltage of the photoelectric conversion module will change, and therefore the photoelectric conversion module modulates the first electric signals according to the direct current bias voltage after superimposition, and generates second odd-order intermodulation components in the modulation process. Since the second odd-order intermodulation components are equal in size and opposite in direction to the first odd-order intermodulation components, the second odd-order intermodulation components and the first odd-order intermodulation components cancel each other out in the process of modulating the first electric signals, so that the target modulation signals finally output do not contain odd-order intermodulation components, thereby reducing the nonlinear distortion of the target modulation signals finally output by the photoelectric conversion module. Therefore, when the device of the application is applied to each analog channel in the hybrid beamforming architecture, the in-band and out-of-band distortions in the output signals can be reduced, and the linearity of the system can be improved.

[0009] In a possible implementation manner of the application, the even-order intermodulation components meeting the preset requirements refer to even-order intermodulation components capable of obtaining the second odd-order intermodulation components.

[0010] In a possible implementation manner of the application, the nonlinear compensation device further comprises a radio frequency output module connected to the first output end of the photoelectric conversion module. The radio frequency output module is configured to shift the target modulation signals output by the photoelectric conversion module through the first output end to a radio frequency carrier frequency and output.

[0011] The radio frequency output module can send the target modulation signals shifted to the radio frequency carrier frequency through an antenna or other sending module.

[0012] In a possible implementation manner of the application, the nonlinear compensation device further comprises a power amplifier. An input end of the power amplifier is connected to the first output end of the photoelectric conversion module, and an output end of the power amplifier is connected to the radio frequency output module. The power amplifier is configured to amplify the target modulation signals output by the photoelectric conversion module through the first output end and provide the radio frequency output module.

[0013] The power amplifier can amplify the signals to be output.

[0014] In a possible implementation of the present application, the processing module comprises a conversion unit and a bias unit. An input end of the conversion unit is connected to the second output end of the photoelectric conversion module, for extracting the even-order intermodulation component meeting the preset requirement from the second electrical signal. An output end of the conversion unit is connected to an input end of the bias unit. The bias unit is configured to superimpose the even-order intermodulation component meeting the preset requirement to the direct current bias voltage of the photoelectric conversion module (such as the first photoelectric detector). In this way, the direct current bias voltage of the photoelectric conversion module can be changed.

[0015] In a possible implementation of the present application, the conversion unit comprises a direct current isolator and an active filter. An input end of the direct current isolator is configured to receive the second electrical signal, an output end of the direct current isolator is connected to an input end of the active filter, and an output end of the active filter is connected to the bias unit. The direct current isolator is configured to isolate the direct current component in the second electrical signal to obtain a second target electrical signal. The active filter is configured to filter out the even-order intermodulation component meeting the preset requirement from the second target electrical signal and provide the even-order intermodulation component meeting the preset requirement to the bias unit.

[0016] In the present application, active filters, bias devices and other low-frequency analog devices are used, and high-speed analog-to-digital conversion devices or digital-to-analog conversion devices are not required, so that the cost is lower and the implementation is easier.

[0017] In a possible implementation of the present application, the photoelectric conversion module comprises a first photoelectric detector and a second photoelectric detector. The first photoelectric detector and the second photoelectric detector are both connected to the mixing module, and the first photoelectric detector and the second photoelectric detector are both connected to the processing module. The first photoelectric detector is configured to convert the first mixed signal into the first electrical signal. The second photoelectric detector is configured to convert the second mixed signal into the second electrical signal and transmit the second electrical signal to the processing module. The first photoelectric detector is further configured to generate the second odd-order intermodulation component in the process of modulating the first electrical signal according to the direct current bias voltage superimposed with the even-order intermodulation component, and finally obtain the target modulation signal.

[0018] In the present application, the photoelectric detector is used as the output stage, which has the advantages of super large bandwidth, flexible frequency band, anti-interference and easy realization of full connection of antenna array.

[0019] In a possible implementation of the present application, the nonlinear compensation device further comprises a direct current bias module. The direct current bias module is configured to provide the first photoelectric detector and the second photoelectric detector with a direct current bias voltage.

[0020] In a possible implementation of the present application, the mixing module is a 3dB coupler. The 3dB coupler has the advantages of small power consumption and high power capacity.

[0021] In a possible implementation of the present application, the first light beam is signal light, and the second light beam is local light.

[0022] In a second aspect, a nonlinear compensation method is provided, including: a nonlinear compensation device performing mixing processing on a received first light beam and a second light beam to obtain first mixed signals and second mixed signals that are reverse signals of each other. The first light beam is a modulated signal, and the second light beam is an unmodulated signal. The nonlinear compensation device obtains a first electrical signal from the first mixed signals, and the first electrical signal contains first odd-order intermodulation components. The nonlinear compensation device obtains a second electrical signal from the second mixed signals. The nonlinear compensation device superimposes even-order intermodulation components that meet preset requirements in the second electrical signal on a direct current bias voltage. The nonlinear compensation device generates second odd-order intermodulation components in a process of modulating the first electrical signal according to the direct current bias voltage superimposed with the even-order intermodulation components, and finally obtains a target modulated signal. The target modulated signal does not contain odd-order intermodulation components, the second odd-order intermodulation components are equal in size and opposite in direction to the first odd-order intermodulation components.

[0023] In a possible implementation of the present application, after the target modulated signal is obtained, the method provided by the present application further includes: the nonlinear compensation device shifting the target modulated signal to a radio frequency carrier frequency and outputting.

[0024] In a possible implementation of the present application, shifting the target modulated signal to a radio frequency carrier frequency and outputting includes: the nonlinear compensation device performing amplification processing on the target modulated signal. The nonlinear compensation device shifts the target modulated signal after the amplification processing to a radio frequency carrier frequency and outputs.

[0025] In a possible implementation of the present application, superimposing the even-order intermodulation components that meet the preset requirements in the second electrical signal on the direct current bias voltage of the first photodetector includes: the nonlinear compensation device isolating direct current components in the second electrical signal to obtain a second target electrical signal. The nonlinear compensation device filters the even-order intermodulation components that meet the preset requirements from the second target electrical signal, and superimposes the even-order intermodulation components that meet the preset requirements on the direct current bias voltage of the first photodetector.

[0026] In a third aspect, a nonlinear compensation system is provided, including a signal processor, a digital channel, one or more analog channels, and a sending module. The signal processor is configured to transmit a to-be-transmitted signal to the digital channel, and the digital channel corresponds to the one or more analog channels. Each analog channel has the nonlinear compensation device in the above-described embodiments. Each analog channel receives a first light beam and a second light beam, and transmits a target modulated signal through the nonlinear compensation device.

[0027] It can be understood that the beneficial effects of the second aspect and the third aspect described above can be referred to the related description in the first aspect described above, and will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of the working principle of a photoelectric detector provided by the present application;

[0029] Figure 2 is a curve diagram of a nonlinear output provided by the present application;

[0030] Figure 3 is a schematic diagram of an existing nonlinear compensation architecture provided by the present application;

[0031] Figure 4 is a beamforming architecture diagram provided by an embodiment of the present application;

[0032] Figure 5 is a schematic diagram of a nonlinear compensation device structure provided by an embodiment of the present application;

[0033] Figure 6 is another schematic diagram of a nonlinear compensation device structure provided by an embodiment of the present application;

[0034] Figure 7 is a schematic diagram of a nonlinear output device provided by an embodiment of the present application;

[0035] Figure 8 is a schematic diagram of a nonlinear compensation device structure with a direct current bias module provided by an embodiment of the present application;

[0036] Figure 9 is another schematic diagram of a nonlinear compensation device structure with a direct current bias module provided by an embodiment of the present application;

[0037] Figure 10 is a schematic diagram of a processing module in a nonlinear compensation device provided by an embodiment of the present application;

[0038] Figure 11 is another schematic diagram of a processing module in a nonlinear compensation device provided by an embodiment of the present application;

[0039] Figure 12 is a schematic diagram of a conversion unit in a processing module provided by an embodiment of the present application;

[0040] Figure 13 is another schematic diagram of a conversion unit in a processing module provided by an embodiment of the present application;

[0041] Figure 14 is a signal output simulation diagram provided by an embodiment of the present application;

[0042] Figure 15 is another signal output simulation diagram provided by an embodiment of the present application;

[0043] Figure 16 is a flow diagram of a nonlinear compensation method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the terms "first", "second", etc. are used to distinguish the same or similar items with basically the same function and role. For example, the first photodetector and the second photodetector are only used to distinguish different photodetectors, and do not limit the order. Those skilled in the art can understand that the terms "first", "second", etc. do not limit the number and execution order, and the terms "first", "second", etc. also do not necessarily mean different.

[0045] It should be noted that in the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design presented as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or advantageous than other embodiments or design solutions. Rather, the use of the words "exemplary" or "for example" is intended to present related concepts in a specific manner.

[0046] In the present application, "at least one" means one or more, and "multiple" means two or more. The association relationship of the associated objects is described, which means that there can be three relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" or similar expressions means any combination of these items, including any combination of single item or multiple items. For example, at least one of a, b, or c, can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0047] Before introducing the embodiments of the present application, first, the related terms involved in the embodiments of the present application are explained as follows:

[0048] 1. Photodetector: a device capable of converting optical signals into electrical signals. It is commonly used in the fields of microwave photonics, optical communication, laser radar, and millimeter wave communication.

[0049] 2. Nonlinear output current: In a photodetector, such as a photodiode, the movement speed of the carriers decreases, resulting in that the output current does not increase linearly with the increase of the input optical power.

[0050] 3. Beamforming: also known as beamforming or spatial filtering, it adjusts the parameters of the basic units of the phase array so that signals at certain angles undergo constructive interference, while signals at other angles undergo destructive interference.

[0051] 4. Hybrid beamforming architecture: This is a beamforming architecture that combines digital beamforming and analog beamforming, where part of the beamforming is done by digital processing in the baseband and part of the beamforming is done by an analog RF beamformer.

[0052] Before providing a detailed explanation of the embodiments of this application, the application scenarios of these embodiments will be described first.

[0053] Common photodetectors are PIN diodes (positive-intrinsic-negative diodes), such as... Figure 1 As shown, the p-type and n-type material regions of a PIN diode are composed of an intrinsic (i) region with slight n-type doping. When the PIN diode is operating normally, the bias voltage completely depletes the carriers in the intrinsic region. When the energy of an incident photon is greater than or equal to the bandgap energy of the intrinsic region, it excites an electron in the valence band of the intrinsic region to absorb the photon's energy, generating an electron-hole pair, i.e., photogenerated carriers. When the high internal electric field of the intrinsic region separates the electron-hole pairs, the electrons and holes flow towards both ends under the influence of the bias voltage and are then collected at the boundary through the electrodes, thus forming a current in the external circuit. As the incident light power increases, the concentration of electrons generated in the intrinsic region increases. The electric field generated by the photogenerated electrons is opposite in direction to the internal electric field, thus weakening the internal electric field and significantly reducing the carrier mobility. Ultimately, this results in the output current not increasing linearly with the increase of the input light power, i.e., a nonlinear output current is generated, such as... Figure 2 .

[0054] Currently, digital predistortion methods are commonly used when dealing with nonlinear output currents. For example... Figure 3As shown, for a power amplifier with nonlinear distortion, its transfer function can be expressed as y = f(x). By introducing a feedback branch, a portion of the output signal can be converted to a digital intermediate frequency (IF) via a down-conversion module and an analog-to-digital converter. Then, a model training module continuously learns and provides feedback by comparing the ideal output with the actual output, adjusting the obtained model parameters to approximate the inverse function of the power amplifier's transfer function, y = f^(-1). Since y = f(f^(-1)) = x, the signal, after passing through a digital predistorter and the power amplifier, will obtain an ideal linear output. This is the solution in traditional electrical beamforming, i.e., beamforming using a power amplifier as the output stage. However, for hybrid beamforming, the aforementioned nonlinear compensation only applies to the output of each digital channel. Since the number of analog channels is far greater than the number of digital channels, there are insufficient degrees of freedom to perform precise pre-compensation for each analog channel.

[0055] To this end, this application proposes a nonlinear compensation method, device, and system. The method uses photodetector bias modulation for nonlinear compensation, which can compensate for the third-order nonlinearity of the photodetector itself, as well as complete the third-order nonlinear distortion compensation of the entire link in which the photodetector is located.

[0056] The following is a detailed explanation of a nonlinear compensation device, method, and system provided in the embodiments of this application.

[0057] Figure 4 This is a schematic diagram of a hybrid beamforming architecture, such as... Figure 4 As shown, the architecture includes one or more analog channels 402, each analog channel 402 being used for mixing to obtain a radio frequency output signal. Each analog channel 402 includes the nonlinear compensation device 50 provided in this embodiment of the application.

[0058] In one possible embodiment of this application, such as Figure 4 As shown, the hybrid beamforming architecture also includes a beam emitting device 401 for generating and emitting beam pairs to one or more analog channels 402 (e.g., analog channel 1 to analog channel n). There can be one or more beam pairs. Each beam pair includes a first beam (signal light) and a second beam (local oscillator light), emitted by a pair of laser emitters. For example, the beam emitting device 401 includes one or more pairs of laser emitters, each pair emitting a signal light and a local oscillator light to one or more analog channels 402.

[0059] As an example, the beam emitting device 401 includes a pair of laser emitters, namely laser emitter A and laser emitter B, laser emitter A emitting signal light to one or more analog channels 402, and laser emitter B emitting local oscillator light to one or more analog channels 402 (e.g., analog channel 1 to analog channel n).

[0060] As another example, the beam emitting device 401 includes two pairs of laser emitters, namely laser emitter A, laser emitter B, laser emitter C, and laser emitter D. Laser emitter A emits signal light, and laser emitter B emits local oscillator light to m analog channels 402 out of a plurality of analog channels 402. Laser emitter C emits signal light, and laser emitter D emits local oscillator light to the other analog channels 402 besides the m analog channels 402.

[0061] It is worth noting that the signal light is a modulated continuous laser emitted by a laser transmitter, used to mix with the local oscillator light to generate a microwave signal. The local oscillator light is an unmodulated continuous laser emitted by a laser transmitter, used to mix with the signal light to generate a microwave signal.

[0062] In one possible embodiment of this application, such as Figure 4 As shown, the hybrid beamforming architecture may further include a transmission module 403. The transmission module 403 is connected to one or more of the analog channels 402 described above. The transmission module 403 is used to transmit the target modulated signal obtained after processing by the nonlinear compensation device 50 in the analog channel 402. For example, the transmission module 403 may be an antenna, a transmitter, etc.

[0063] The following embodiment uses a beam emitting device 401 to emit a pair of beams to multiple analog channels 402, each analog channel 402 including a nonlinear compensation device 50 as an example.

[0064] like Figure 5 As shown, Figure 5 This is a schematic diagram of a nonlinear compensation device provided in an embodiment of this application. The nonlinear compensation device 50 includes: a mixing module 501, a photoelectric conversion module 502 connected to the mixing module 501, and a processing module 503 connected to the photoelectric conversion module 502.

[0065] The mixing module 501 is used to perform mixing processing on the first beam and the second beam to obtain a first mixed signal and a second mixed signal that are opposite signals to each other. The first beam is a modulated signal, and the second beam is an unmodulated signal.

[0066] The photoelectric conversion module 502 is configured to convert the first mixed frequency signal into a first electrical signal, convert the second mixed frequency signal into a second electrical signal, and transmit the second electrical signal to the processing module 503. The first electrical signal comprises at least a first odd-order intermodulation component.

[0067] The processing module 503 is configured to extract an even-order intermodulation component meeting a preset requirement from the second electrical signal, and superimpose the even-order intermodulation component on a direct current bias voltage of the photoelectric conversion module 502.

[0068] The photoelectric conversion module 502 is configured to generate a second odd-order intermodulation component in the process of modulating the first electrical signal according to the direct current bias voltage superimposed with the even-order intermodulation component, and finally obtain a target modulation signal. The target modulation signal does not contain the first odd-order intermodulation component. The second odd-order intermodulation component is equal in size and opposite in direction to the first odd-order intermodulation component.

[0069] In an embodiment of the present application, the first mixed frequency signal and the second mixed frequency signal are opposite signals, which can be understood as the first mixed frequency signal and the second mixed frequency signal being opposite numbers.

[0070] In the nonlinear compensation device provided by the present application, the first light beam and the second light beam are first mixed by the mixing module to obtain the first mixed frequency signal and the second mixed frequency signal which are opposite signals. Then, the photoelectric conversion module obtains the first electrical signal and the second electrical signal according to the first mixed frequency signal and the second mixed frequency signal. Since the first electrical signal comprises the first odd-order intermodulation component, it indicates that there is nonlinear distortion in the first electrical signal. Therefore, in order to reduce the nonlinear distortion of the target modulation signal finally output by the photoelectric conversion module, the second electrical signal is sent to the processing module, so that the processing module can obtain the even-order intermodulation component meeting the preset requirement from the second electrical signal. The even-order intermodulation component meeting the preset requirement is superimposed on the direct current bias voltage of the photoelectric conversion module. Since the even-order intermodulation component is superimposed on the direct current bias voltage of the photoelectric conversion module, the direct current bias voltage of the photoelectric conversion module will change. Therefore, the photoelectric conversion module modulates the first electrical signal according to the direct current bias voltage after superimposition, and generates the second odd-order intermodulation component in the modulation process. Since the second odd-order intermodulation component is equal in size and opposite in direction to the first odd-order intermodulation component, the second odd-order intermodulation component and the first odd-order intermodulation component cancel each other out in the process of modulating the first electrical signal, so that the target modulation signal finally output does not contain the odd-order intermodulation component, thereby reducing the nonlinear distortion of the target modulation signal finally output by the photoelectric conversion module. Therefore, when the device of the present application is applied to each analog channel in the hybrid beamforming architecture, the in-band and out-of-band distortions in the output signal can be reduced, and the linearity of the system can be improved.

[0071] In an embodiment of the present application, the mixing module 501 is a three-decibel directional coupler (3dB coupler), the first light beam is signal light, and the second light beam is local oscillator light. The 3dB coupler is a kind of multi-input and multi-output optical coupling device. For example, the 3dB coupler in the embodiment of the present application can be a two-input and two-output 3dB coupler, that is, the 3dB coupler has two output ends, namely a first input end, a second input end, a first output end, and a second output end. Specifically, the first input end of the 3dB coupler is used to receive signal light, and the second input end is used to receive local oscillator light. The 3dB coupler is used to mix the signal light and the local oscillator light to obtain two-way reverse mixed output, that is, a first mixed signal and a second mixed signal. The 3dB coupler outputs the first mixed signal through the first output end and outputs the second mixed signal through the second output end to the photoelectric conversion module 502. The 3dB coupler has the advantages of small power consumption and high power capacity.

[0072] Of course, it can be understood that the mixing module 501 can also use other devices that can mix the first light beam and the second light beam to obtain the first mixed signal and the second mixed signal, and the embodiments of the present application do not limit this.

[0073] In a possible embodiment of the present application, the electrical signal (i.e. the first electrical signal or the second electrical signal) includes a plurality of odd-order intermodulation components and a plurality of even-order intermodulation components, wherein the odd-order intermodulation component with the largest proportion in the electrical signal is a third-order intermodulation component, and the even-order intermodulation component is a second-order intermodulation component. For example, the odd-order intermodulation component can be a third-order intermodulation component, a fifth-order intermodulation component, etc., and the even-order intermodulation component can be a second-order intermodulation component, a fourth-order intermodulation component, etc. In the following embodiments, the odd-order intermodulation component is a third-order intermodulation component, and the even-order intermodulation component is a second-order intermodulation component.

[0074] It can be understood that in the first electrical signal output by the photoelectric conversion module 502, the third-order intermodulation component (first third-order intermodulation component) is an important parameter of nonlinear output, that is, suppressing the first third-order intermodulation component in the first electrical signal can compensate for nonlinear output.

[0075] It can be understood that the photoelectric conversion module 502 in the embodiment of the present application has two input ends and two output ends, i.e. a first input end, a second input end, a first output end and a second output end. The input signal received by the first input end of the photoelectric conversion module 502 is the first mixed frequency signal, and it can also be understood that the first input end of the photoelectric conversion module 502 is connected with the first output end of the mixing module 501. The input signal received by the second input end of the photoelectric conversion module 502 is the second mixed frequency signal, and it can also be understood that the second input end of the photoelectric conversion module 502 is connected with the second output end of the mixing module 501. The first output end of the photoelectric conversion module 502 is used to output the target modulation signal, for example, the first output end can be connected with the radio frequency output module 504, or connected with the radio frequency output module 504 through the power amplifier 505. The second output end of the photoelectric conversion module 502 is used to provide the second electrical signal to the processing module 503, i.e. the second output end is connected with the processing module 503.

[0076] In a possible embodiment of the present application, the photoelectric conversion module 502 can include a plurality of sub-photoelectric conversion modules, such as a first sub-photoelectric conversion module and a second sub-photoelectric conversion module. As an example, the sub-photoelectric conversion module can be a photoelectric detector. The sub-photoelectric conversion module can of course also be other devices that can convert a light beam into an electrical signal. As shown in Figure 5 Figure 5 For example, the photoelectric conversion module 502 includes a first photoelectric detector 5021 and a second photoelectric detector 5022. The input ends of the first photoelectric detector 5021 and the second photoelectric detector 5022 are connected with the mixing module 501. The output end of the first photoelectric detector 5021 is connected with the radio frequency output module 504. The output end of the second photoelectric detector 5022 is connected with the processing module 503. The first photoelectric detector 5021 is used to convert the first mixed frequency signal into a first electrical signal. The second photoelectric detector 5022 is used to convert the second mixed frequency signal into a second electrical signal and transmit it to the processing module 503. Correspondingly, the processing module 503 is used to extract the even-order intermodulation components (such as the second-order intermodulation component) meeting the preset requirements from the second electrical signal, and is used to superimpose the even-order intermodulation components on the direct current bias voltage of the first photoelectric detector 5021. The first photoelectric detector 5021 is used to generate a second third-order intermodulation component in the process of modulating the first electrical signal according to the direct current bias voltage superimposed with the even-order intermodulation component, and finally obtain the target modulation signal.

[0077] ​It is understandable that, when the photoelectric conversion module 502 includes a first photodetector 5021 and a second photodetector 5022, the first input terminal of the photoelectric conversion module 502 is the input terminal of the first photodetector 5021. The second input terminal of the photoelectric conversion module 502 is the input terminal of the second photodetector 5022. The first output terminal of the photoelectric conversion module 502 is the output terminal of the first photodetector 5021. The second output terminal of the photoelectric conversion module 502 is the output terminal of the second photodetector 5022.

[0078] As an example, such as Figure 5 As shown, assuming the input signal (i.e., the first mixing signal) of the first photodetector 5021 is x, x satisfies x = cosω1t + cosω2t, where ω1 and ω2 represent the first and second angular frequencies of the signal, and t is time. The output signal (i.e., the first electrical signal) y of the first photodetector 5021 can be expressed as y = a0 + a1(cosω1t + cosω2t) + a2(cosω1t + cosω2t). 2 +a3(cosω1t+cosω2t) 3 Where a i (i = 0, 1, 2, 3…) represents the Taylor expansion coefficients of the transmission characteristic curve of the first photodetector 5021 at the operating point. Since even-order intermodulation components in the nonlinear composition are usually far from the fundamental frequency component in the spectrum and are easily filtered out, while higher-order odd-order intermodulation components typically have lower power, the lower-order third-order intermodulation components become important parameters for suppressing nonlinearity. The first and third-order intermodulation components can be expressed as y imd3 =3a3cos(2ω1-ω2)t / 4.

[0079] Specifically, the first photodetector 5021 is also used to generate a second and third order intermodulation component during the modulation of the first electrical signal. Since the second and third order intermodulation components are equal in magnitude and opposite in direction to the first and third order intermodulation components, the second and third order intermodulation components cancel out the first and third order intermodulation components in the first electrical signal during the modulation process. Therefore, a target modulation signal that does not contain the first and third order intermodulation components can be obtained in the end.

[0080] It can be understood that, taking the even order intermodulation component as an example, the processing module 503 is configured to filter out the second order intermodulation component meeting the preset requirement in the second electric signal output by the second photoelectric detector 5022, and superimpose the second order intermodulation component meeting the preset requirement on the direct current bias voltage of the first photoelectric detector 5021. The first photoelectric detector 5021 generates a second third order intermodulation component in the process of modulating the first electric signal according to the direct current bias voltage superimposed with the second order intermodulation component meeting the preset requirement. The second third order intermodulation component is a second third order intermodulation component with the same size and opposite direction as the first third order intermodulation component, so as to offset the first third order intermodulation component in the first electric signal.

[0081] As an example, the second third order intermodulation component is Δ imd3 When Δ imd3 + y imd3 = 0, the non-linear output of the first photoelectric detector 5021 is compensated.

[0082] In one possible embodiment of the present application, the non-linear compensation device 50 further comprises a radio frequency output module 504 connected with the first output end of the photoelectric conversion module 502. The radio frequency output module 504 is configured to shift the target modulation signal output by the photoelectric conversion module 502 through the first output end to a radio frequency carrier frequency and output.

[0083] Specifically, as shown in Figure 5 , Figure 8 , Figure 10 and Figure 12 , the radio frequency output module 504 is connected with the output end of the first photoelectric detector 5021. As shown in the non-linear compensation device schematic diagram in Figure 6 , Figure 9 , Figure 11 and Figure 13 , the radio frequency output module 504 is connected with the output end of the power amplifier 505. The radio frequency output module 504 is configured to shift the target modulation signal to a radio frequency carrier frequency and output.

[0084] Optionally, the output end of the radio frequency output module 504 is connected with the sending module 403 (such as an antenna), so that the radio frequency output module 504 can output the target modulation signal located on the radio frequency carrier frequency to the sending module 403, so as to send the target modulation signal located on the radio frequency carrier frequency by using the sending module 403.

[0085] In one possible implementation manner of the present application, generally in order to realize high power output, as Figure 6As shown, the nonlinear compensation device 50 may further include a power amplifier 505. The input terminal of the power amplifier 505 is connected to the first output terminal of the photoelectric conversion module (e.g., the output terminal of the first photodetector 5021), and the output terminal of the power amplifier 505 is connected to the radio frequency output module 504. The power amplifier 505 amplifies the signal (e.g., a first electrical signal or a target modulation signal) output from the first output terminal of the photoelectric conversion module and then provides it to the radio frequency output module 504.

[0086] It is understandable that the first photodetector 5021 outputs a first electrical signal to the power amplifier 505 to obtain an amplified first electrical signal. Since the power amplifier 505 is also a nonlinear output device, the first third-order intermodulation component in the amplified first electrical signal is jointly determined by the power amplifier 505 and the first photodetector 5021.

[0087] As an example, such as Figure 7 As shown, Figure 7 This is a nonlinear generating device, which consists of a first photodetector 5021 and a power amplifier 505. The first electrical signal output from the first photodetector 5021 passes through the power amplifier 505. At this time, the third-order intermodulation component in the amplified first electrical signal output by the power amplifier 505 consists of two parts, the first part being y... imd3-PA1 This refers to the fundamental frequency component of the first photodetector 5021 and the third-order intermodulation component of the power amplifier 505. The second part is y. imd3-PA2 These represent the third-order intermodulation components of the first photodetector 5021 and the fundamental frequency component of the power amplifier 505. Wherein, y imd3-PA1 =3a'1 3 b3 / 4, y imd3-PA2 = a'3b1, where a'1 is the fundamental frequency component of the first photodetector 5021, and a'3 is the third-order intermodulation component of the first photodetector 5021. a'1 and a'3 are controlled by the processing module 503. When the processing module 503 makes y imd3-PA1 and y imd3-PA2 When the magnitudes are equal but the directions are opposite, the third-order intermodulation component in the amplified first electrical signal output by the power amplifier 505 can be suppressed.

[0088] In one embodiment of this application, the nonlinear compensation device 50 further includes a DC bias module 506. The DC bias module 506 is used to provide a DC bias voltage for the first photodetector 5021 and the second photodetector 5022 (i.e., the photoelectric conversion module 502).

[0089] As an example, with Figure 5 Taking the nonlinear compensation device shown as an example, such as Figure 8As shown in FIG. 6, the DC bias module 506 is connected to the first photodetector 5021 and the second photodetector 5022. The even-order intermodulation components meeting the preset requirements output by the processing module 503 and the DC bias voltage output by the DC bias module 506 jointly act on the first photodetector 5021. It can be understood that the processing module 503 superimposes the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021.

[0090] As another example, the nonlinear compensation device as shown in FIG. 6 is taken as an example. As shown in FIG. 6, the processing module 503 includes a conversion unit 5031 and a bias unit 5032. The input end of the conversion unit 5031 is connected to the second output end of the photoelectric conversion module 502 (for example, the output end of the second photodetector 5022), for extracting the even-order intermodulation components meeting the preset requirements from the second electrical signal. The bias unit 5032 is used for superimposing the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021 in the photoelectric conversion module 502. Figure 6 As shown in FIG. 6, the DC bias module 506 is connected to the first photodetector 5021 and the second photodetector 5022. The even-order intermodulation components meeting the preset requirements output by the processing module 503 and the DC bias voltage output by the DC bias module 506 jointly act on the first photodetector 5021. It can be understood that the processing module 503 superimposes the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021. Figure 9 As shown in FIG. 6, the DC bias module 506 is connected to the first photodetector 5021 and the second photodetector 5022. The even-order intermodulation components meeting the preset requirements output by the processing module 503 and the DC bias voltage output by the DC bias module 506 jointly act on the first photodetector 5021. It can be understood that the processing module 503 superimposes the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021.

[0091] It is worth mentioning that the DC bias module 506 can be one or two. It can be understood that one DC bias module 506 simultaneously provides the DC bias voltage for the first photodetector 5021 and the second photodetector 5022, or two DC bias modules 506 respectively provide the DC bias voltage for the first photodetector 5021 and the second photodetector 5022.

[0092] In one possible embodiment of the present application, as shown in FIG. 6, the processing module 503 includes a conversion unit 5031 and a bias unit 5032. The input end of the conversion unit 5031 is connected to the second output end of the photoelectric conversion module 502 (for example, the output end of the second photodetector 5022), for extracting the even-order intermodulation components meeting the preset requirements from the second electrical signal. The bias unit 5032 is used for superimposing the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021 in the photoelectric conversion module 502. Figure 10 As an example, the nonlinear compensation device as shown in FIG. 6 is taken as an example. As shown in FIG. 6, the processing module 503 includes a conversion unit 5031 and a bias unit 5032. The input end of the conversion unit 5031 is connected to the second output end of the photoelectric conversion module 502 (for example, the output end of the second photodetector 5022), for extracting the even-order intermodulation components meeting the preset requirements from the second electrical signal. The bias unit 5032 is used for superimposing the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021 in the photoelectric conversion module 502.

[0093] Figure 8 As another example, the nonlinear compensation device as shown in FIG. 6 is taken as an example. As shown in FIG. 6, the processing module 503 includes a conversion unit 5031 and a bias unit 5032. The input end of the conversion unit 5031 is connected to the second output end of the photoelectric conversion module 502 (for example, the output end of the second photodetector 5022), for extracting the even-order intermodulation components meeting the preset requirements from the second electrical signal. The bias unit 5032 is used for superimposing the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021 in the photoelectric conversion module 502. Figure 10 As shown in FIG. 6, the DC bias module 506 is connected to the first photodetector 5021 and the second photodetector 5022. The even-order intermodulation components meeting the preset requirements output by the processing module 503 and the DC bias voltage output by the DC bias module 506 jointly act on the first photodetector 5021. It can be understood that the processing module 503 superimposes the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021.

[0094] Figure 9 As another example, the nonlinear compensation device as shown in FIG. 6 is taken as an example. As shown in FIG. 6, the processing module 503 includes a conversion unit 5031 and a bias unit 5032. The input end of the conversion unit 5031 is connected to the second output end of the photoelectric conversion module 502 (for example, the output end of the second photodetector 5022), for extracting the even-order intermodulation components meeting the preset requirements from the second electrical signal. The bias unit 5032 is used for superimposing the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021 in the photoelectric conversion module 502. Figure 11 As shown in FIG. 6, the DC bias module 506 is connected to the first photodetector 5021 and the second photodetector 5022. The even-order intermodulation components meeting the preset requirements output by the processing module 503 and the DC bias voltage output by the DC bias module 506 jointly act on the first photodetector 5021. It can be understood that the processing module 503 superimposes the even-order intermodulation components meeting the preset requirements on the DC bias voltage of the first photodetector 5021.

[0095] ​​In one possible embodiment of this application, the conversion unit 5031 includes a DC blocker 5033 and an active filter 5034, such as Figure 12 As shown. The input terminal of DC blocker 5033 is connected to the second output terminal of photoelectric conversion module 502 to receive the second electrical signal, and the output terminal of active filter 5034 is connected to bias unit 5032 to output a second-order intermodulation component that meets the preset requirements.

[0096] Specifically, the output of DC blocker 5033 is connected to the input of active filter 5034. DC blocker 5033 is used to isolate the DC component in the second electrical signal to obtain the second target electrical signal. Active filter 5034 is used to filter out the even-order intermodulation components that meet the preset requirements from the second target electrical signal and provide the even-order intermodulation components that meet the preset requirements to bias unit 5032.

[0097] Specifically, by controlling the amplification factor of the active filter 5034, the magnitude of the even-order intermodulation component obtained from the second target electrical signal can be changed, thereby obtaining an even-order intermodulation component that meets the preset requirements. This allows the even-order intermodulation component that meets the preset requirements to be superimposed onto the DC bias voltage, so that the photoelectric conversion module 502, during the modulation of the first electrical signal, obtains a second odd-order intermodulation component that is equal in magnitude but opposite in direction to the first odd-order intermodulation component, thus canceling out the first odd-order intermodulation component in the first electrical signal.

[0098] As an example, with Figure 12 Taking the nonlinear compensation device shown as an example, after passing through the DC blocker 5033 and the active filter 5034, the output of the second photodetector 5022... It can be represented as Where k is the amplification factor of the active filter 5034, After being superimposed on the DC bias voltage output by the DC bias module 506, a second- or third-order intermodulation component Δ will be generated in the output of the first photodetector 5021. imd3 , can be represented as Where m is the bias modulation coefficient of the first photodetector 5021. When the second and third order intermodulation components are equal in magnitude and opposite in direction to the first and third order intermodulation components, the amplification coefficient k of the active filter 5034 can be expressed as k = -3a3 / (2a1a2 + 9a2a3 / 2)m.

[0099] In another possible embodiment of this application, such as Figure 13 As shown, the output of the first photodetector 5021 is connected to the power amplifier 505. The third-order intermodulation component in the amplified first electrical signal output by the power amplifier 505 consists of the fundamental frequency component of the first photodetector 5021 and the third-order component y from the power amplifier 505.imd3-PA1 The third-order component of the first photodetector 5021 and the fundamental frequency component y of the power amplifier 505. imd3-PA2 Composition. Wherein, y imd3-PA1 =3a'1 3 b3 / 4, y imd3-PA2 = a'3b1, where a'1 is the fundamental frequency component of the first photodetector 5021, and a'3 is the third-order intermodulation component of the first photodetector 5021. When there is no second photodetector 5022 and no conversion unit 5031 in the processing module 503, a'1 = a1, a'3 = 3a3 / 4. When the second photodetector 5022 sends the second electrical signal to the processing module 503, after processing by the DC blocker 5033 and the active filter 5034, a'1 ← a1 + mk(a1a2 / 2 + 3a2a3 / 2), a'3 ← 3a3 / 4 + mk(a1a2 / 2 + 9a2a3 / 8).

[0100] It is understandable that when y imd3-PA1 and y imd3-PA2 When the magnitudes are equal but the directions are opposite, that is, when the amplification factor k of the active filter 5034 is adjusted, so that a'1 3 When / a'3=-4b1 / 3b3 is true, the third-order intermodulation component in the output of power amplifier 505 can be suppressed.

[0101] In one embodiment of this application, taking the output terminal of the first photodetector 5021 connected to the radio frequency output module 504 as an example, as follows... Figure 5 , Figure 8 , Figure 10 and Figure 12 The amplification factor k of the active filter 5034 in the control processing module 503 can suppress the third-order intermodulation component in the first electrical signal. Simulations were performed using a 16-orthogonal amplitude modulation signal with a carrier frequency of 28 GHz and a bandwidth of 800 MHz. The simulation results are as follows: Figure 14 As shown, Figure 14 Figure (a) shows the adjacent channel leakage ratio without the nonlinear compensation device described in the embodiments of this application. Figure 14 Figure (b) shows the error vector magnitude diagram when the nonlinear compensation device in the embodiments of this application is not used. Figure 14 Figure (c) in the figure shows the leakage ratio between adjacent channels when using the nonlinear compensation device in the embodiments of this application. Figure 14Figure (d) in the drawings is an error vector magnitude diagram when the nonlinear compensation device in the embodiment of the present application is used. As can be seen, when the nonlinear compensation device in the embodiment of the present application is not used, the adjacent channel leakage ratio (ACLR) of the output signal is 29.8 dB, and the error vector magnitude (EVM) is 8.4%. When the nonlinear compensation device in the embodiment of the present application is used, the adjacent channel leakage ratio is increased to 37.6 dB, and the error vector magnitude (EVM) is optimized to 1.78%, which obviously reduces the in-band and out-of-band distortion in the output signal and shows good nonlinear suppression capability.

[0102] In another embodiment of the present application, the output end of the first photodetector 5021 is connected to the input end of the power amplifier 505, and the output end of the power amplifier 505 is connected to the radio frequency output module 504, for example. Figure 6 、 Figure 9 、 Figure 11 and Figure 13 The amplification coefficient k of the active filter 5034 in the control processing module 503 can be controlled to suppress the third-order intermodulation component in the first electrical signal. Similarly, a 16 quadrature amplitude modulation signal with a carrier frequency of 28 GHz and a bandwidth of 800 MHz is simulated, and the simulation results are shown in Figure 15 , Figure 15 Figure (a) in the drawings is an adjacent channel leakage ratio diagram when the nonlinear compensation device in the embodiment of the present application is not used, Figure 15 Figure (b) in the drawings is an error vector magnitude diagram when the nonlinear compensation device in the embodiment of the present application is not used, Figure 15 Figure (c) in the drawings is an adjacent channel leakage ratio diagram when the nonlinear compensation device in the embodiment of the present application is used, Figure 15 Figure (d) in the drawings is an error vector magnitude diagram when the nonlinear compensation device in the embodiment of the present application is used. As can be seen, when the nonlinear compensation device in the embodiment of the present application is not used, the adjacent channel leakage ratio (ACLR) of the output signal is 29.8 dB, and the error vector magnitude (EVM) is 8.4%. When the nonlinear compensation device in the embodiment of the present application is used, the adjacent channel leakage ratio is increased to 37.6 dB, and the error vector magnitude (EVM) is optimized to 1.78%, which obviously reduces the in-band and out-of-band distortion in the output signal and shows good nonlinear suppression capability.

[0103] Figure 16 A flowchart of a nonlinear compensation method provided by an embodiment of the present application is shown in FIG. 6. The method is applied to a hybrid beamforming architecture. The hybrid beamforming architecture includes one or more analog channels 402, and each analog channel 402 includes a nonlinear compensation device 50.

[0104] Taking the odd-order intermodulation component as the third-order intermodulation component and the even-order intermodulation component as the second-order intermodulation component as an example, as shown in FIG. 5, the nonlinear compensation method provided by the embodiment of the present application includes: Figure 16

[0105] Step 601: The nonlinear compensation device 50 performs mixing processing on the received first light beam and second light beam to obtain first mixed signals and second mixed signals that are reverse signals of each other. The first light beam is a modulated signal, and the second light beam is an unmodulated signal.

[0106] For example, step 601 can be specifically performed by the mixing module 501.

[0107] Step 602: The nonlinear compensation device 50 obtains a first electrical signal from the first mixed signal, and the first electrical signal contains first odd-order intermodulation components.

[0108] Step 603: The nonlinear compensation device 50 obtains a second electrical signal from the second mixed signal.

[0109] For example, steps 602 and 603 can be specifically performed by the photoelectric conversion module 502. In the case where the photoelectric conversion module 502 includes a first photoelectric detector 5021 and a second photoelectric detector 5022, step 602 is performed by the first photoelectric detector 5021. Step 603 is performed by the second photoelectric detector 5022.

[0110] Step 604: The nonlinear compensation device 50 superimposes even-order intermodulation components that meet preset requirements in the second electrical signal on a direct current bias voltage of the photoelectric conversion module.

[0111] For example, step 604 can be performed by the processing module 503. In the case where the first photoelectric detector 5021 and the second photoelectric detector 5022 are provided with direct current bias voltages by different direct current bias voltage units, the processing module 503 is configured to superimpose the even-order intermodulation components that meet the preset requirements on the direct current bias voltage of the first photoelectric detector 5021.

[0112] Step 605: The nonlinear compensation device 50 generates second odd-order intermodulation components in the process of modulating the first electrical signal according to the direct current bias voltage superimposed with the even-order intermodulation components, and finally obtains a target modulated signal.

[0113] ​The target modulation signal does not contain odd-order intermodulation components. The second odd-order intermodulation component is equal in size and opposite in direction to the first odd-order intermodulation component.

[0114] For example, the step 605 can be performed by the photoelectric conversion module 502. More specifically, the step 605 can be performed by the first photoelectric detector 5021 in the photoelectric conversion module 502.

[0115] In one possible implementation of the present application, the method provided by the embodiments of the present application can further include, after the step 605, the nonlinear compensation device 50 shifting the target modulation signal to a radio frequency carrier frequency and outputting the target modulation signal. For example, the photoelectric conversion module 502 outputs the target modulation signal to the radio frequency output module 504, and the radio frequency output module 504 shifts the target modulation signal to the radio frequency carrier frequency and outputs the target modulation signal to the transmitting module.

[0116] In one possible implementation of the present application, the nonlinear compensation device 50 shifts the target modulation signal to the radio frequency carrier frequency and outputs the target modulation signal, which can be achieved by the following manner: the nonlinear compensation device 50 amplifies the target modulation signal. And the nonlinear compensation device 50 shifts the amplified target modulation signal to the radio frequency carrier frequency and outputs the amplified target modulation signal. For example, the photoelectric conversion module 502 outputs the target modulation signal to the power amplifier 505. The power amplifier 505 amplifies the target modulation signal and outputs the amplified target modulation signal to the radio frequency output module 504. The radio frequency output module 504 shifts the amplified target modulation signal to the radio frequency carrier frequency and outputs the amplified target modulation signal to the transmitting module.

[0117] In one possible implementation of the present application, the nonlinear compensation device 50 superimposes the required even-order intermodulation components in the second electrical signal to the direct current bias voltage of the first photoelectric detector, including: the nonlinear compensation device 50 isolates the direct current component in the second electrical signal to obtain a second target electrical signal. The nonlinear compensation device 50 filters the even-order intermodulation components meeting the preset requirements from the second target electrical signal, and superimposes the even-order intermodulation components meeting the preset requirements to the direct current bias voltage of the first photoelectric detector. For example, the nonlinear compensation device 50 isolates the direct current component in the second electrical signal by an isolator to obtain a second target electrical signal. The nonlinear compensation device 50 filters the even-order intermodulation components meeting the preset requirements from the second target electrical signal by an active filter, and superimposes the even-order intermodulation components meeting the preset requirements to the direct current bias voltage of the first photoelectric detector.

[0118] The embodiment of the present application provides a kind of nonlinear compensation system, system includes signal processor, digital channel, one or more analog channels and sending module.Signal processor is used to transmit signal to digital channel, and digital channel corresponds one or more analog channels.Each analog channel has the nonlinear compensation device of the above embodiment in it.Each analog channel receives first light beam and second light beam, and sends target modulation signal by nonlinear compensation device.

[0119] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0120] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0121] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / computer device and method can be implemented in other ways. For example, the apparatus / computer device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed mutual ones can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0122] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A non-linear compensation device, characterized by, The nonlinear compensation device comprises a mixing module, an optoelectronic conversion module connected with the mixing module, and a processing module connected with the optoelectronic conversion module, wherein The mixing module is configured to mix the first light beam and the second light beam to obtain a first mixed signal and a second mixed signal which are reverse signals of each other, the first light beam being a modulated signal, and the second light beam being an unmodulated signal; The optoelectronic conversion module is configured to convert the first mixed signal into a first electric signal, convert the second mixed signal into a second electric signal, and transmit the second electric signal to the processing module, the first electric signal comprising at least first odd-order intermodulation components; The processing module is configured to extract even-order intermodulation components meeting preset requirements from the second electric signal, and superimpose the even-order intermodulation components on a direct current bias voltage of the optoelectronic conversion module; The optoelectronic conversion module is configured to generate second odd-order intermodulation components in the process of modulating the first electric signal according to the direct current bias voltage superimposed with the even-order intermodulation components, and finally obtain a target modulated signal, the target modulated signal not containing odd-order intermodulation components, the second odd-order intermodulation components being equal in size and opposite in direction to the first odd-order intermodulation components.

2. The non-linear compensating device of claim 1, wherein, The nonlinear compensation device further comprises a radio frequency output module connected with a first output end of the optoelectronic conversion module, the radio frequency output module being configured to shift the target modulated signal output by the optoelectronic conversion module through the first output end to a radio frequency carrier frequency and output.

3. The non-linear compensating device of claim 2, wherein, The nonlinear compensation device further comprises a power amplifier, an input end of the power amplifier being connected with the first output end of the optoelectronic conversion module, and an output end of the power amplifier being connected with the radio frequency output module; the power amplifier being configured to amplify the target modulated signal output by the optoelectronic conversion module through the first output end and provide the amplified signal to the radio frequency output module.

4. The non-linear compensating device according to any one of claims 1 to 3, characterized in that The processing module comprises a conversion unit and a bias unit, an input end of the conversion unit being connected with a second output end of the optoelectronic conversion module, the conversion unit being configured to extract the even-order intermodulation components meeting preset requirements from the second electric signal, and an output end of the conversion unit being connected with an input end of the bias unit; the bias unit being configured to superimpose the even-order intermodulation components meeting preset requirements on the direct current bias voltage of the optoelectronic conversion module.

5. The non-linear compensation device of claim 4, wherein, The conversion unit comprises a direct current isolator and an active filter, an input end of the direct current isolator being configured to receive the second electric signal, an output end of the direct current isolator being connected with an input end of the active filter, and an output end of the active filter being connected with the bias unit, the direct current isolator being configured to isolate direct current components in the second electric signal to obtain a second target electric signal; the active filter being configured to filter out the even-order intermodulation components meeting preset requirements from the second target electric signal, and provide the even-order intermodulation components meeting preset requirements to the bias unit.

6. The non-linear compensation device according to any one of claims 1 to 5, characterized in that The photoelectric conversion module comprises a first photoelectric detector and a second photoelectric detector, the first photoelectric detector and the second photoelectric detector are connected with the mixing module, and the first photoelectric detector and the second photoelectric detector are connected with the processing module; The first photoelectric detector is used for converting the first mixed signal into the first electric signal; the second photoelectric detector is used for converting the second mixed signal into a second electric signal and transmitting to the processing module; The first photoelectric detector is also used for generating the second odd-order intermodulation component in the process of modulating the first electric signal according to the direct current bias voltage superimposed with the even-order intermodulation component, and finally obtaining the target modulation signal.

7. The non-linear compensation device according to claim 6, characterized in that The nonlinear compensation device further comprises a direct current bias module, The direct current bias module is used for providing the first photoelectric detector and the second photoelectric detector with the direct current bias voltage.

8. The non-linear compensation device according to any one of claims 1 to 7, characterized in that The mixing module is a 3dB coupler.

9. The non-linear compensating device according to any one of claims 1 to 8, characterized in that The first light beam is signal light, and the second light beam is local oscillator light.

10. A method of non-linear compensation, characterized by, The method comprises: mixing the received first light beam and second light beam to obtain first mixed signal and second mixed signal which are reverse signals of each other, the first light beam is a modulated signal, and the second light beam is an unmodulated signal; obtaining a first electric signal according to the first mixed signal, the first electric signal containing first odd-order intermodulation component; obtaining a second electric signal according to the second mixed signal; superimposing even-order intermodulation component meeting preset requirements in the second electric signal on a direct current bias voltage of a photoelectric conversion module; generating second odd-order intermodulation component in the process of modulating the first electric signal according to the direct current bias voltage superimposed with the even-order intermodulation component, and finally obtaining a target modulation signal, the target modulation signal not containing odd-order intermodulation component, the second odd-order intermodulation component being equal in size and opposite in direction to the first odd-order intermodulation component.

11. The method of non-linear compensation according to claim 10, wherein, After obtaining the target modulation signal, the method further comprises: shifting the target modulation signal to a radio frequency carrier frequency and outputting.

12. The method of non-linear compensation according to claim 11, wherein, The shifting the target modulation signal to a radio frequency carrier frequency and outputting comprises: amplifying the target modulation signal; shifting the amplified target modulation signal to a radio frequency carrier frequency and outputting.

13. The method of non-linear compensation according to any of claims 10 to 12, characterized in that, The superimposing even-order intermodulation component meeting preset requirements in the second electric signal on a direct current bias voltage of a first photoelectric detector comprises: isolating direct current component in the second electric signal to obtain a second target electric signal; filtering the even-order intermodulation component meeting preset requirements from the second target electric signal, and superimposing the even-order intermodulation component meeting preset requirements on a direct current bias voltage of a first photoelectric detector.

14. A non-linear compensation system characterized by, The system comprises a signal processor, one digital channel, one or more analog channels, and a sending module; The signal processor is used for transmitting signals to the digital channel, and the digital channel corresponds to one or more analog channels; Each analog channel has the nonlinear compensation device in any one of claims 1-9.

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