CN118282527A

CN118282527A - Multi-frequency optical local oscillation generating device, method and communication system

Info

Publication number: CN118282527A
Application number: CN202211647184.1A
Authority: CN
Inventors: 陈文娟; 段向阳; 范忱; 吕凯林; 吴赛博; 宗柏青
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2022-12-21
Filing date: 2022-12-21
Publication date: 2024-07-02
Also published as: WO2024131038A1

Abstract

The embodiment of the application provides a multi-frequency optical local oscillator generating device, a multi-frequency optical local oscillator generating method and a communication system, and belongs to the field of microwave photons. The multi-frequency optical local oscillation generating device comprises a carrier modulation module, a photoelectric conversion module and a radio frequency configuration module; the carrier modulation module comprises an in-phase quadrature IQ modulator, wherein the IQ modulator is used for being connected with a laser source so as to carry out quadrature modulation on an optical carrier output by the laser source to obtain a modulated optical signal; the photoelectric conversion module is connected with the carrier modulation module and used for converting the modulated optical signals into electric signals; the radio frequency configuration module is connected with the photoelectric conversion module and is used for configuring the electric signals into radio frequency signals with a plurality of preset frequencies; the IQ modulator is also connected to the radio frequency configuration module, and is further used for coupling the plurality of radio frequency signals with the optical carrier wave respectively to obtain a multi-frequency optical local oscillation signal. The technical scheme of the embodiment of the application aims to reduce the cost of generating the multi-frequency optical local oscillator and improve the frequency spectrum utilization rate.

Description

Multi-frequency optical local oscillation generating device, method and communication system

Technical Field

The present application relates to the technical field of microwave photons, and in particular, to a device, a method, and a communication system for generating a multi-frequency optical local oscillator.

Background

With the development of communication technology, electrical devices have failed to meet the requirement of high bandwidth due to the limitation of operating bandwidth. Microwave photon technology has become a solution to this dilemma because of its advantages of ultra-large bandwidth, low loss, high parallelism, low crosstalk, etc. Multi-band radio frequency transceivers of photonic technology typically require the generation of a set of highly coherent optical local oscillators in the optical domain to achieve multi-frequency conversion. Whereas limited spectrum resources allocated in the communication field are usually fragmented, for example, for a spectrum range of 40GHz, it is usually only necessary to process several narrowband frequency points, such as 2.6GHz, 3.5GHz, 4.9GHz, 28GHz, 39GHz, etc.

At present, a common method of photon technology is to use a group of optical frequency combs as a multi-frequency optical local oscillator, and the corresponding multi-frequency optical local oscillator is a group of frequency spectrums with equidifferent frequencies, so that a group of optical frequency combs with extremely small comb teeth (in the order of MHz) and extremely many comb teeth (hundreds of combs) are needed to cover all fragmented frequency spectrum ranges. The method has the advantages that the harsh requirements are put on the generation of the optical frequency comb, the cost is high, and a large amount of local oscillation comb teeth resources are in an idle state, so that the frequency spectrum utilization rate is low.

Disclosure of Invention

The embodiment of the application provides a device, a method and a communication system for generating a multi-frequency optical local oscillator, which aim to reduce the cost for generating the multi-frequency optical local oscillator and improve the frequency spectrum utilization rate.

In a first aspect, an embodiment of the present application provides a multi-frequency optical local oscillation generating device, including:

The carrier modulation module comprises an in-phase quadrature (IQ) modulator, and the IQ modulator is used for being connected with a laser source so as to carry out quadrature modulation on an optical carrier output by the laser source to obtain a modulated optical signal;

The photoelectric conversion module is connected with the carrier modulation module and used for converting the modulated optical signals into electric signals; the radio frequency configuration module is connected with the photoelectric conversion module and is used for configuring the electric signals into radio frequency signals with a plurality of preset frequencies;

The IQ modulator is further connected to the radio frequency configuration module, and is further configured to couple the plurality of radio frequency signals with the optical carrier respectively to obtain a multi-frequency optical local oscillation signal.

In a second aspect, an embodiment of the present application further provides a method for generating a multi-frequency optical local oscillator, which is applied to a multi-frequency optical local oscillator generating device, where the multi-frequency optical local oscillator generating device includes a carrier modulation module, a photoelectric conversion module and a radio frequency configuration module; the carrier modulation module comprises an in-phase quadrature (IQ) modulator, and the IQ modulator is used for being connected with a laser source; the photoelectric conversion module is connected with the carrier modulation module, the radio frequency configuration module is connected with the photoelectric conversion module, and the IQ modulator is also connected with the radio frequency configuration module; the method comprises the following steps:

Quadrature modulation is carried out on the optical carrier wave output by the laser source through the IQ modulator, so as to obtain a modulated optical signal; converting the modulated optical signal into an electrical signal by the photoelectric conversion module; configuring the electric signals into a plurality of radio frequency signals with preset frequencies through the radio frequency configuration module; and respectively coupling a plurality of radio frequency signals with the optical carrier wave through the IQ modulator to obtain a multi-frequency optical local oscillation signal.

In a third aspect, embodiments of the present application further provide a communication system, where the communication system includes a transmitting link and a receiving link; and any one of the multi-frequency optical local oscillation generating devices provided by the embodiment of the application is used for providing multi-frequency optical local oscillation signals for the transmitting link and the receiving link.

The embodiment of the application provides a multi-frequency optical local oscillator generating device, a method and a communication system, wherein the multi-frequency optical local oscillator generating device comprises a carrier modulation module, a photoelectric conversion module and a radio frequency configuration module; the carrier modulation module comprises an in-phase quadrature IQ modulator, wherein the IQ modulator is used for being connected with a laser source so as to carry out quadrature modulation on an optical carrier output by the laser source to obtain a modulated optical signal; the photoelectric conversion module is connected with the carrier modulation module and used for converting the modulated optical signals into electric signals; the radio frequency configuration module is connected with the photoelectric conversion module and is used for configuring the electric signals into radio frequency signals with a plurality of preset frequencies; the IQ modulator is also connected to the radio frequency configuration module, and is further used for coupling the plurality of radio frequency signals with the optical carrier wave respectively to obtain a multi-frequency optical local oscillation signal. According to the embodiment of the application, the IQ modulator is used for coupling the radio frequency signals with the preset frequencies with the optical carrier, so that sideband multiplexing of the local oscillation frequency is realized, the optical local oscillation signals with multiple frequency bands can be obtained in a high cost performance mode, the cost for generating the multi-frequency optical local oscillation is effectively reduced, and the frequency spectrum utilization rate is improved.

Drawings

Fig. 1 is a schematic block diagram of a multi-frequency optical local oscillation generating device according to an embodiment of the present application;

Fig. 2 is a schematic block diagram of another multi-frequency optical local oscillation generating device according to an embodiment of the present application;

Fig. 3 is a schematic block diagram of another multi-frequency optical local oscillation generating device according to an embodiment of the present application;

fig. 4 is a schematic block diagram of another multi-frequency optical local oscillation generating device according to an embodiment of the present application;

Fig. 5 is a schematic block diagram of another multi-frequency optical local oscillation generating device according to an embodiment of the present application;

fig. 6 is a schematic block diagram of another multi-frequency optical local oscillation generating device according to an embodiment of the present application;

Fig. 7 is a schematic block diagram of another multi-frequency optical local oscillation generating apparatus according to an embodiment of the present application;

fig. 8 is a schematic flow chart of steps of a method for generating a multi-frequency optical local oscillator according to an embodiment of the present application;

Fig. 9 is a schematic block diagram of a communication system according to an embodiment of the present application;

Fig. 10 is a schematic block diagram of another communication system according to an embodiment of the present application;

Fig. 11 is a schematic block diagram of still another communication system according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The flow diagrams depicted in the figures are merely illustrative and not necessarily all of the elements and operations/steps are included or performed in the order described. For example, some operations/steps may be further divided, combined, or partially combined, so that the order of actual execution may be changed according to actual situations.

It is to be understood that the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

Referring to fig. 1, fig. 1 is a schematic block diagram of a multi-frequency optical local oscillation generating apparatus according to an embodiment of the present application.

As shown in fig. 1, the multi-frequency optical local oscillation generating apparatus 100 includes a carrier modulation module 110, a photoelectric conversion module 120, and a radio frequency configuration module 130. The multi-frequency optical local oscillation generating device 100 is connected to the laser source 10, the laser source 10 is configured to output an optical carrier, and the multi-frequency optical local oscillation generating device 100 can generate a multi-frequency optical local oscillation signal by using the optical carrier output by the laser source 10.

The carrier modulation module 110 includes an in-phase quadrature IQ modulator, which is used for connecting with the laser source 10 to perform quadrature modulation on an optical carrier output by the laser source 10, so as to obtain a modulated optical signal. The photoelectric conversion module 120 is connected to the carrier modulation module 110, and is configured to convert the modulated optical signal into an electrical signal. The radio frequency configuration module 130 is connected to the photoelectric conversion module 120, and is configured to configure the electrical signal into radio frequency signals with a plurality of preset frequencies. The IQ modulator is further connected to the radio frequency configuration module 130, and the IQ modulator is further configured to couple the plurality of radio frequency signals with the optical carrier, respectively, to obtain a multi-frequency optical local oscillation signal.

The laser source 10 may be a single wavelength light source, and the optical carrier may be a single wavelength optical signal. The IQ modulator may be a mach-zehnder modulator, where the photoelectric conversion module 120 is capable of performing photoelectric conversion on the modulated optical signal to obtain an electrical signal, and then the radio frequency configuration module 130 configures the electrical signal obtained by the photoelectric conversion into a plurality of radio frequency signals with preset frequencies, where the preset frequencies of the plurality of radio frequency signals may be the same or different, and the radio frequency configuration module 130 may couple the radio frequency signals with the same or different preset frequencies with the optical carrier, so as to modulate the plurality of radio frequency signals on the left and right sides of the optical carrier, and obtain a multi-frequency optical local oscillation signal. The multi-frequency optical local oscillator signals can be two or more than two optical local oscillator signals, an optical frequency comb or a plurality of groups of photoelectric oscillators with high cost are not needed, the cost for generating the multi-frequency optical local oscillator is effectively reduced, and the frequency spectrum utilization rate is improved.

As shown in fig. 2, the carrier modulation module 110 includes an IQ modulator 111, where the IQ modulator 111 includes two components, I and Q arms, and the I and Q arms in the IQ modulator 111 divide an optical carrier into two paths for carrier modulation, where the two paths of optical carriers are orthogonal to each other, that is, two paths of optical carriers with the same frequency and a phase difference of 90 degrees are respectively modulated and then transmitted together, so as to implement sideband multiplexing of local oscillation frequencies of the optical carriers, and improve spectrum utilization.

Illustratively, as shown in fig. 2, the carrier modulation module 110 further includes a single mode optical fiber 112; the single-mode fiber 112 is connected to the IQ modulator 111, and is configured to delay the modulated optical signal output from the IQ modulator 111. It should be noted that, the delayed modulated optical signal is obtained by delaying the modulated optical signal by the single-mode fiber 112, and the delayed modulated optical signal is used to complete the closed loop through the rf configuration module 130 after being input to the photoelectric conversion module 120, so that the stability of the closed loop can be improved.

It should be noted that, after the IQ modulator 111 obtains the multi-frequency optical local oscillation signal, the multi-frequency optical local oscillation signal may be output after the delay of the single-mode fiber 112, or may be directly output without the delay of the single-mode fiber 112, which is not specifically limited in the embodiment of the present application.

In one embodiment, as shown in fig. 2, the photoelectric conversion module 120 includes a photodetector 121 and an amplifier 122; the photodetector 121 is connected to the carrier modulation module 110, and is used for converting the modulated optical signal into an electrical signal; the amplifier 122 is connected to the photodetector 121 for amplifying the electric signal.

It should be noted that the photoelectric conversion module 120 may be one or more paths, the multiple paths of photoelectric conversion modules 120 may include multiple groups of photodetectors 121 and multiple groups of amplifiers 122, and the specific paths of the photoelectric conversion modules 120 may be determined according to practical situations. In some embodiments, the photoelectric conversion module 120 may also include only a photodetector for converting a modulated optical signal into an electrical signal, which is not particularly limited in this embodiment.

In one embodiment, as shown in fig. 2, the rf configuration module 130 includes a power divider 131 and a first filter bank 132; the power divider 131 is connected with the photoelectric conversion module 120 and is used for distributing power of the electric signals; the first filter bank 132 is connected to the power divider 131, and the first filter bank 132 is configured to perform frequency selection on the electrical signal to obtain a plurality of radio frequency signals with preset frequencies. The preset frequency may be preset multiple frequencies, such as F1, F2, etc., and the power allocation may be power average allocation, so as to improve system stability. It should be noted that, the first filter bank 132 may include a plurality of electric filters, the power divider 131 may divide the power of the electric signal according to the number of the plurality of electric filters, and each electric filter may perform frequency selection on the electric signal after power division based on the preset frequency set by each electric filter, so as to obtain a radio frequency signal of the preset frequency corresponding to each electric filter.

In an embodiment, as shown in fig. 2 and 3, the first filter bank 132 includes a first electric filter 1321 and a second electric filter 1322, and the first electric filter 1321 and the second electric filter 1322 are connected to the power divider; the first electric filter 1321 is configured to perform frequency selection on the electric signal according to a first preset frequency, so as to obtain a first radio frequency signal; the second electric filter 1322 is configured to perform frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal; the first electric filter 1321 and the second electric filter 1322 are further connected to the controlled end of the IQ modulator 111, and the IQ modulator 111 is further configured to couple the first radio frequency signal and the second radio frequency signal to two sides of a sideband of the optical carrier, respectively, to obtain two-frequency optical local oscillation signals.

It should be noted that, the first electric filter 1321 and the second electric filter 1322 may be adjustable electric filters, the first preset frequency and the second preset frequency may be set according to practical situations, the frequency of the first radio frequency signal obtained by the frequency selection of the first electric filter 1321 may be the first preset frequency, the frequency of the second radio frequency signal obtained by the frequency selection of the second electric filter 1322 may be the second preset frequency, and the IQ modulator 111 may couple the first radio frequency signal and the second radio frequency signal to two sides of a sideband of the optical carrier respectively, thereby implementing the side-path multiplexing of the optical carrier, and improving the spectrum utilization rate.

Illustratively, the first radio frequency signal obtained by the first electric filter 1321 through frequency selection is f1, and the second radio frequency signal obtained by the second electric filter 1322 through frequency selection is f2. With the bias voltage of the IQ-modulator 111, the IQ-modulator 111 is made to operate in a single sideband modulation format such that the first radio frequency signal f1 modulated at the I-arm will appear to the left (or right) of the carrier frequency fc, while the second radio frequency signal f2 modulated at the Q-arm will appear to the right (or left) of the carrier frequency fc. The radio frequency signals output from the first and second electric filters respectively drive the I and Q arms of the IQ modulator 111 to be quadrature modulated, whereby two optical local oscillation signals fc-f1, fc+f2 can be obtained.

It should be understood that, when the photoelectric conversion module 120 is one path, the rf configuration module 130 may be one path. When the photoelectric conversion module 120 is multiple, the rf configuration module 130 may be multiple. When the rf configuration module 130 is one-way, the first filter bank 132 may include other electric filters besides the first electric filter and the second electric filter, for example, a third electric filter, etc. When the rf configuration module 130 is multi-path, the first filter banks 132 may be multiple sets, and the number of the plurality of electric filters in each set of the first filter banks 132 may be equal or unequal, that is, the multi-path rf configuration module 130 may each include at least one set of the first filter banks 132.

In one embodiment, the IQ modulator may be plural. The carrier modulation module 110 also includes a coupler. The coupler is connected with the IQ modulators and is used for coupling the modulated optical signals output by the IQ modulators. As shown in fig. 4 and fig. 5, taking two IQ modulators 111 as an example, the carrier modulation module 110 further includes a coupler 113 connected to the two IQ modulators 111, it should be noted that the coupler 113 couples the modulated optical signals output by the two IQ modulators 111 to obtain coupled modulated optical signals, and the coupler 113 is further configured to output the coupled modulated optical signals to the photoelectric conversion module 120.

Illustratively, as shown in fig. 4, the photoelectric conversion module 120 includes a photodetector 121 and an amplifier 122. The photodetector 121 is connected to the coupler 113, and is configured to convert the coupled modulated optical signal into an electrical signal; the amplifier 122 is connected to the photodetector 121 for amplifying the electric signal. The radio frequency configuration module 130 comprises a power divider 131 and two electrical filter banks; the power divider 131 is connected to the amplifier 122 and is used for dividing the power of the amplified electric signal; one of the electric filter groups includes a first electric filter 1321 and a second electric filter 1322, the other electric filter group includes a third electric filter 1323 and a fourth electric filter 1324, and each of the first electric filter 1321, the second electric filter 1322, and the third electric filter 1323 and the fourth electric filter 1324 is connected to the power divider 131. The first electric filter 1321 is configured to perform frequency selection on the electric signal according to a first preset frequency, so as to obtain a first radio frequency signal f1; the second electric filter 1322 is configured to perform frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal f2; the first and second electric filters 1321 and 1322 are further connected to a controlled end of an IQ modulator 111, and the IQ modulator 111 is further configured to couple the first radio frequency signal f1 and the second radio frequency signal f2 to two sides of a sideband of the optical carrier fc, respectively, to obtain two frequency optical local oscillation signals fc-f1 and fc+f2. The third electric filter 1323 is configured to perform frequency selection on the electric signal according to a third preset frequency, so as to obtain a third radio frequency signal f3; the fourth electric filter 1324 is configured to perform frequency selection on the electric signal according to a fourth preset frequency, so as to obtain a fourth radio frequency signal f4; the third and fourth electric filters 1323 and 1324 are further connected to the controlled end of the other IQ modulator 111, and the other IQ modulator 111 is further configured to couple the third radio frequency signal f3 and the fourth radio frequency signal f4 to two sides of the sidebands of the optical carrier fc respectively, so as to obtain two frequency optical local oscillation signals fc-f4 and fc+f3.

In one embodiment, as shown in fig. 5, the photoelectric conversion module 120 includes a beam splitter 123, a plurality of photodetectors 121, and a plurality of amplifiers 122; the beam splitter 123 is connected to the coupler 113, and is configured to split the coupled modulated optical signal into a plurality of sub-modulated optical signals, and output the plurality of sub-modulated optical signals to a plurality of photodetectors, respectively; each photodetector 121 is connected to the beam splitter 123, and the photodetectors 121 are configured to convert the sub-modulated optical signals into sub-electrical signals; each amplifier 122 is connected with the plurality of photodetectors 121 in a one-to-one correspondence manner, and the amplifiers 122 are used for amplifying the sub-electrical signals; each amplifier 122 is further connected to a plurality of rf configuration modules 130 in a one-to-one correspondence, and the rf configuration modules 130 are configured to configure the amplified sub-electrical signals to rf signals with a preset frequency.

Illustratively, as shown in FIG. 5, the RF configuration module 130 includes two power dividers 131 and two electrical filter banks; the two power dividers 131 are connected with the amplifier 122 and are used for distributing power to the amplified sub-electric signals; one of the electric filter groups includes a first electric filter 1321 and a second electric filter 1322, the other electric filter group includes a third electric filter 1323 and a fourth electric filter 1324, the first electric filter 1321, the second electric filter 1322 are connected to one of the power splitters 131, and the third electric filter 1323, the fourth electric filter 1324 are connected to the other power splitter 131. The first electric filter 1321 is configured to perform frequency selection on the sub-electric signal according to a first preset frequency, so as to obtain a first radio frequency signal f1; the second electric filter 1322 is configured to perform frequency selection on the sub-electric signal according to a second preset frequency to obtain a second radio frequency signal f2; the first and second electric filters 1321 and 1322 are further connected to a controlled end of an IQ modulator 111, and the IQ modulator 111 is further configured to couple the first radio frequency signal f1 and the second radio frequency signal f2 to two sides of a sideband of the optical carrier fc, respectively, to obtain two frequency optical local oscillation signals fc-f1 and fc+f2. The third electric filter 1323 is configured to perform frequency selection on the sub-electric signal according to a third preset frequency, so as to obtain a third radio frequency signal f3; the fourth electric filter 1324 is configured to perform frequency selection on the electrical signal according to a fourth preset frequency, so as to obtain a fourth radio frequency signal f4; the third and fourth electric filters 1323 and 1324 are further connected to the controlled end of the other IQ modulator 111, and the other IQ modulator 111 is further configured to couple the third radio frequency signal f3 and the fourth radio frequency signal f4 to two sides of the sidebands of the optical carrier fc respectively, so as to obtain two frequency optical local oscillation signals fc-f4 and fc+f3.

In an embodiment, as shown in fig. 6, the IQ modulator 111 includes a first IQ modulator 1111 and a second IQ modulator 1112, and the carrier modulation module 110 further includes a first polarization beam splitter 1141 and a first polarization beam combiner 1142; the first polarization beam splitter 1141 is connected to the laser source 10, and is configured to split the optical carrier into a first polarization signal and a second polarization signal; the first IQ modulator 1111 is connected to the first polarization beam splitter 1141, and is configured to quadrature modulate the first polarization state signal to obtain a first modulated optical signal; the second IQ modulator 1112 is connected to the first polarization beam splitter 1141, and is configured to quadrature modulate the second polarization state signal to obtain a second modulated optical signal; the polarization beam combiner 1142 is connected to the first IQ modulator 1111 and the second IQ modulator 1112, and is configured to combine the first modulated optical signal and the second modulated optical signal to obtain a modulated optical signal, where the modulated optical signal is a polarization-multiplexed optical signal.

In an embodiment, as shown in fig. 6, the photoelectric conversion module 120 includes a first polarization controller 1241, a second polarization beam splitter 1242, a first photoelectric conversion unit 1201, and a second photoelectric conversion unit 1202; the first polarization controller 1241 is connected to the first polarization beam combiner 1142, and the first polarization controller 1241 is configured to control the second polarization beam splitter 1242 according to the polarization state angle of the first polarization beam splitter 1141, so that the polarization state angles of the second polarization beam splitter 1242 and the first polarization beam splitter 1141 are kept the same; the second polarization beam splitter 1242 is connected to the first polarization controller 1241, and the second polarization beam splitter 1242 is used for splitting the modulated optical signal into a third polarization state signal and a fourth polarization state signal; the first photoelectric conversion unit 1201 and the second photoelectric conversion unit 1202 are connected with the second polarization beam splitter 1242, the first photoelectric conversion unit 1201 is used for converting the third polarization state signal into the first electric signal, and the second photoelectric conversion unit 1202 is used for converting the fourth polarization state signal into the second electric signal; the first photoelectric conversion unit 1201 and the second photoelectric conversion unit 1202 are further connected to the rf configuration module 130, and the rf configuration module 130 is configured to configure the first electrical signal and the second electrical signal into two rf signals with preset frequencies, respectively.

As illustrated in fig. 6 and 7, the first photoelectric conversion unit 1201 and the second photoelectric conversion unit 1202 include one-way photodetectors 121 and amplifiers 122, respectively. The photodetector 121 is connected to the second polarization beam splitter 1242, and is configured to convert the third polarization signal or the fourth polarization signal into an electrical signal; the amplifier 122 is connected to the photodetector 121 for amplifying the electric signal. The radio frequency configuration module 130 comprises a power divider 131 and two electrical filter banks 132; the power divider 131 is connected to the amplifier 122 and is used for dividing the power of the amplified electric signal; one of the electric filter groups 132 includes a first electric filter 1321 and a second electric filter 1322, the other electric filter group 132 includes a third electric filter 1323 and a fourth electric filter 1324, and each of the first electric filter 1321, the second electric filter 1322, and the third electric filter 1323 and the fourth electric filter 1324 is connected to the power divider 131. The first electric filter 1321 is configured to perform frequency selection on the electric signal according to a first preset frequency, so as to obtain a first radio frequency signal f1; the second electric filter 1322 is configured to perform frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal f2; the first and second electric filters 1321 and 1322 are further connected to a controlled end of an IQ modulator 111, and the IQ modulator 111 is further configured to couple the first radio frequency signal f1 and the second radio frequency signal f2 to two sides of a sideband in the X polarization state of the optical carrier fc, respectively, to obtain two frequency optical local oscillation signals fc-f1 and fc+f2 in the X polarization state. The third electric filter 1323 is configured to perform frequency selection on the electric signal according to a third preset frequency, so as to obtain a third radio frequency signal f3; the fourth electric filter 1324 is configured to perform frequency selection on the electric signal according to a fourth preset frequency, so as to obtain a fourth radio frequency signal f4; the third electric filter 1323 and the fourth electric filter 1324 are further connected to the controlled end of the other IQ modulator 111, and the other IQ modulator 111 is further configured to couple the third radio frequency signal f3 and the fourth radio frequency signal f4 to two sides of the sidebands on the Y polarization state of the optical carrier fc respectively, so as to obtain two frequency optical local oscillation signals fc-f4 and fc+f3 on the Y polarization state.

It should be noted that, as shown in fig. 6 and fig. 7, the input optical carrier forms independent oscillation loops on two orthogonal polarization states, and then uses sideband multiplexing of the IQ modulator on each polarization state to form two independent oscillation loops on the upper and lower optical sidebands, so that four independent optoelectronic oscillator loops can be generated by using one IQ modulator to obtain four independent optical local oscillator signals fc-f1, fc+f2, fc-f4, fc+f3, and each optical local oscillator signal can realize frequency independent tuning by means of an electric filter in each loop. Through the principles of sideband multiplexing and polarization multiplexing, the spectrum utilization rate is effectively improved, and the device is compact in structure and high in cost performance.

It should be noted that the embodiment of the application aims to overcome the defects of high cost and great waste of spectrum resources in the existing multi-frequency optical local oscillator implementation mode, and provides a multi-frequency optical local oscillator generation scheme based on sideband multiplexing and polarization multiplexing, which realizes simultaneous generation of four independent coherent optical local oscillator signals with adjustable frequencies on a single circuit in a multi-multiplexing mode, not only can realize flexible reconfiguration of the optical local oscillator signals in a wide spectrum range, but also improves the spectrum utilization rate in a high cost performance mode, and has obvious advantages compared with the traditional photoelectric oscillator which can only generate one oscillation frequency in one path.

The multi-frequency optical local oscillation generating device 100 provided in the above embodiment includes a carrier modulation module 110, a photoelectric conversion module 120, and a radio frequency configuration module 130; the carrier modulation module 110 includes an in-phase quadrature IQ modulator 111, where the IQ modulator 111 is configured to be connected to the laser source 10, so as to perform quadrature modulation on an optical carrier output by the laser source 10, to obtain a modulated optical signal; the photoelectric conversion module 120 is connected with the carrier modulation module 110 and is used for converting the modulated optical signal into an electrical signal; the radio frequency configuration module 130 is connected to the photoelectric conversion module 120, and is configured to configure the electrical signal into radio frequency signals with a plurality of preset frequencies; the IQ modulator 111 is further connected to the radio frequency configuration module 130, and the IQ modulator 111 is further configured to couple a plurality of radio frequency signals with the optical carrier, respectively, to obtain a multi-frequency optical local oscillation signal. According to the embodiment of the application, the IQ modulator 111 is used for coupling a plurality of radio frequency signals with preset frequencies with the optical carrier, so that sideband multiplexing of local oscillation frequencies is realized, a multi-frequency optical local oscillation signal can be obtained in a high cost performance mode, the cost for generating the multi-frequency optical local oscillation is effectively reduced, and the frequency spectrum utilization rate is improved.

Referring to fig. 8, fig. 8 is a schematic flow chart of steps of a method for generating a multi-frequency optical local oscillator according to an embodiment of the present application.

The multi-frequency optical local oscillation generating method can be applied to a multi-frequency optical local oscillation generating device, and the multi-frequency optical local oscillation generating device comprises a carrier modulation module, a photoelectric conversion module and a radio frequency configuration module; the carrier modulation module comprises an in-phase quadrature IQ modulator, and the IQ modulator is used for being connected with a laser source; the photoelectric conversion module is connected with the carrier modulation module, the radio frequency configuration module is connected with the photoelectric conversion module, and the IQ modulator is also connected with the radio frequency configuration module. It should be noted that, the multi-frequency optical local oscillation generating device may refer to the multi-frequency optical local oscillation generating device in fig. 1 to 7.

As shown in fig. 8, the method for generating the multi-frequency optical local oscillation includes steps S201 to S204. The following is a specific description:

step S201, quadrature modulation is carried out on an optical carrier wave output by a laser source through an IQ modulator, and a modulated optical signal is obtained.

It should be noted that the laser source may be a single wavelength light source, and the optical carrier may be a single wavelength optical signal. The IQ modulator may be a mach-zehnder modulator. For example, the IQ modulator 111 includes two components, I arm and Q arm, and the I arm and the Q arm in the IQ modulator 111 divide the optical carrier into two paths for carrier modulation, where the two paths of optical carriers are orthogonal to each other, that is, the two paths of optical carriers with the same frequency and a phase difference of 90 degrees are respectively modulated and then transmitted together, so as to obtain a modulated optical signal.

In an embodiment, the carrier modulation module further comprises a single mode fiber; the single-mode fiber is connected with the IQ modulator and is used for delaying the modulated optical signal output by the IQ modulator. The delayed modulated optical signal is used for completing the closed loop through the radio frequency configuration module after being input into the photoelectric conversion module, so that the stability of the closed loop can be improved.

In one embodiment, the IQ modulator may be plural. The carrier modulation module further includes a coupler. The coupler is connected with the IQ modulators and is used for coupling the modulated optical signals output by the IQ modulators.

In an embodiment, the IQ modulator comprises a first IQ modulator and a second IQ modulator, and the carrier modulation module further comprises a first polarizing beam splitter and a first polarizing beam combiner; the first polarization beam splitter is connected with the laser source and is used for dividing the optical carrier into a first polarization state signal and a second polarization state signal; the first IQ modulator is connected with the first polarization beam splitter and used for quadrature modulating the first polarization state signal to obtain a first modulated optical signal; the second IQ modulator is connected with the first polarization beam splitter and used for quadrature modulating the second polarized state signal to obtain a second modulated optical signal; the polarization beam combiner is connected with the first IQ modulator and the second IQ modulator and is used for combining the first modulated optical signal and the second modulated optical signal to obtain a modulated optical signal, and the modulated optical signal is a polarization multiplexing optical signal.

Step S202, the modulated optical signal is converted into an electric signal through a photoelectric conversion module.

In one embodiment, the photoelectric conversion module includes a photodetector and an amplifier; the photoelectric detector is connected with the carrier modulation module and is used for converting the modulated optical signals into electric signals; the amplifier is connected with the photoelectric detector and is used for amplifying the electric signal. It should be noted that the photoelectric conversion modules may be one or more paths, and the multiple paths of photoelectric conversion modules may include multiple groups of photoelectric detectors and multiple groups of amplifiers, and the specific paths of the photoelectric conversion modules may be determined according to actual situations. In some embodiments, the photoelectric conversion module may also include only a photodetector for converting the modulated optical signal into an electrical signal, which is not particularly limited in this embodiment.

In an embodiment, the IQ modulators are plural, and in the case that the carrier modulation module further includes a coupler, the photodetectors in the photoelectric conversion module are connected to the coupler, and are configured to convert the coupled modulated optical signals into electrical signals; the amplifier is connected with the photoelectric detector and is used for amplifying the electric signal.

In an embodiment, in a case that the IQ modulators are plural and the carrier modulation module further includes a coupler, the photoelectric conversion module includes a beam splitter, plural photodetectors, and plural amplifiers; the beam splitter is connected with the coupler and is used for dividing the coupled modulated optical signals into a plurality of sub-modulated optical signals and respectively outputting the sub-modulated optical signals to the plurality of photodetectors; each photoelectric detector is connected with the beam splitter and is used for converting the sub-modulated optical signals into sub-electrical signals; each amplifier is connected with the plurality of photoelectric detectors in a one-to-one correspondence manner and is used for amplifying the sub-electric signals; each amplifier is also connected with a plurality of radio frequency configuration modules in a one-to-one correspondence manner, and the radio frequency configuration modules are used for configuring the amplified sub-electric signals into radio frequency signals with preset frequencies.

In an embodiment, in case that the IQ modulator includes a first IQ modulator and a second IQ modulator, the photoelectric conversion module may include a first polarization controller, a second polarization beam splitter, a first photoelectric conversion unit, and a second photoelectric conversion unit; the first polarization controller is connected with the first polarization beam combiner and is used for controlling the second polarization beam splitter according to the polarization state angle of the first polarization beam splitter so as to keep the polarization state angles of the second polarization beam splitter and the first polarization beam splitter the same; the second polarization beam splitter is connected with the first polarization controller and is used for dividing the modulated light signal into a third polarization state signal and a fourth polarization state signal; the first photoelectric conversion unit and the second photoelectric conversion unit are connected with the second polarization beam splitter, the first photoelectric conversion unit is used for converting the third polarized state signal into a first electric signal, and the second photoelectric conversion unit is used for converting the fourth polarized state signal into a second electric signal; the first photoelectric conversion unit and the second photoelectric conversion unit are also connected with a radio frequency configuration module, and the radio frequency configuration module is used for respectively configuring the first electric signal and the second electric signal into radio frequency signals with two preset frequencies.

Step S203, the electrical signals are configured into a plurality of radio frequency signals with preset frequencies through a radio frequency configuration module.

It should be noted that, the radio frequency configuration module configures the electrical signals obtained by the photoelectric conversion into radio frequency signals with a plurality of preset frequencies, the preset frequencies of the plurality of radio frequency signals may be the same or different, and the radio frequency configuration module may also output radio frequency signals with the same or different preset frequencies to the IQ modulator.

In one embodiment, the radio frequency configuration module includes a power divider and a first filter bank; the power divider is connected with the photoelectric conversion module and is used for distributing power of the electric signals; the first filter bank is connected with the power divider and is used for carrying out frequency selection on the electric signals to obtain a plurality of radio frequency signals with preset frequencies.

The preset frequency may be preset multiple frequencies, such as F1, F2, etc., and the power allocation may be power average allocation, so as to improve system stability. It should be noted that, the first filter bank may include a plurality of electric filters, the power divider may perform power division on the electric signal according to the number of the plurality of electric filters, and each electric filter performs frequency selection on the electric signal after power division based on a preset frequency set by each electric filter, so as to obtain a radio frequency signal of a preset frequency corresponding to each electric filter.

The first filter bank includes a first electric filter and a second electric filter, the first electric filter and the second electric filter being connected to the power divider; the first electric filter is used for carrying out frequency selection on the electric signal according to a first preset frequency to obtain a first radio frequency signal; the second electric filter is used for carrying out frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal; the first electric filter and the second electric filter are also connected with a controlled end of the IQ modulator, and the IQ modulator is also used for respectively coupling the first radio frequency signal and the second radio frequency signal to two sides of a sideband of the optical carrier wave to obtain two-frequency optical local oscillation signals.

It should be noted that, the first electrical filter and the second electrical filter may be adjustable electrical filters, the first preset frequency and the second preset frequency may be set according to practical situations, the frequency of the first radio frequency signal obtained by the first electrical filter through frequency selection may be the first preset frequency, the frequency of the second radio frequency signal obtained by the second electrical filter through frequency selection may be the second preset frequency, and the IQ modulator may couple the first radio frequency signal and the second radio frequency signal to two sides of a sideband of an optical carrier respectively, thereby realizing side multiplexing of the optical carrier and improving the spectrum utilization rate.

In an embodiment, in case the IQ modulator comprises a first IQ modulator and a second IQ modulator, the radio frequency configuration module comprises a power divider and two electrical filter groups; the power divider is connected with the amplifier and is used for dividing the power of the amplified electric signal; one of the electric filter groups comprises a first electric filter and a second electric filter, the other electric filter group comprises a third electric filter and a fourth electric filter, and the first electric filter, the second electric filter, the third electric filter and the fourth electric filter are connected with the power divider. The first electric filter is used for carrying out frequency selection on the electric signal according to a first preset frequency to obtain a first radio frequency signal f1; the second electric filter is used for carrying out frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal f2. The third electric filter is used for carrying out frequency selection on the electric signal according to a third preset frequency to obtain a third radio frequency signal f3; the fourth electric filter is used for carrying out frequency selection on the electric signal according to a fourth preset frequency to obtain a fourth radio frequency signal f4.

Step S204, coupling the plurality of radio frequency signals with the optical carrier wave respectively through the IQ modulator to obtain the multi-frequency optical local oscillation signals.

It should be noted that, radio frequency signals with the same or different preset frequencies can be respectively coupled with the optical carrier through the IQ modulator, so that a plurality of radio frequency signals are modulated on the left side and the right side of the optical carrier to obtain a multi-frequency optical local oscillation signal. The multi-frequency optical local oscillator signals can be two or more than two optical local oscillator signals, an optical frequency comb or a plurality of groups of photoelectric oscillators with high cost are not needed, the cost for generating the multi-frequency optical local oscillator is effectively reduced, and the frequency spectrum utilization rate is improved.

In an embodiment, in the case that the IQ modulator is one, the first radio frequency signal obtained by the first electric filter through frequency selection is f1, and the second radio frequency signal obtained by the second electric filter through frequency selection is f2. With the bias voltage of the IQ-modulator, the IQ-modulator is made to operate in a single sideband modulation format such that the first radio frequency signal f1 modulated at the I-arm will appear to the left (or right) of the carrier frequency fc, while the second radio frequency signal f2 modulated at the Q-arm will appear to the right (or left) of the carrier frequency fc. The radio frequency signals output by the first and second electric filters respectively drive the I and Q arms of the IQ modulator to perform quadrature modulation, whereby two optical local oscillation signals fc-f1, fc+f2 can be obtained.

In an embodiment, where the IQ-modulator is plural and the carrier modulation module further comprises a coupler, the radio frequency configuration module comprises, for example, two electrical filter sets, one of which comprises a first electrical filter and a second electrical filter, and the other of which comprises a third electrical filter and a fourth electrical filter. The first electric filter is used for carrying out frequency selection on the sub-electric signal according to a first preset frequency to obtain a first radio frequency signal f1; the second electric filter is used for carrying out frequency selection on the sub-electric signal according to a second preset frequency to obtain a second radio frequency signal f2; the first and second electric filters are also connected to the controlled end of an IQ modulator, and the IQ modulator is further configured to couple the first radio frequency signal f1 and the second radio frequency signal f2 to two sides of the sidebands of the optical carrier fc, respectively, to obtain two frequency optical local oscillation signals fc-f1, fc+f2. The third electric filter is used for carrying out frequency selection on the sub-electric signal according to a third preset frequency to obtain a third radio frequency signal f3; the fourth electric filter is used for carrying out frequency selection on the sub-electric signal according to a fourth preset frequency to obtain a fourth radio frequency signal f4; the third and fourth electric filters are also connected with the controlled end of another IQ modulator, and the other IQ modulator is further configured to couple the third radio frequency signal f3 and the fourth radio frequency signal f4 to two sides of the sidebands of the optical carrier fc respectively, so as to obtain two frequency optical local oscillation signals fc-f4 and fc+f3.

In an embodiment, in case the IQ modulator comprises a first IQ modulator and a second IQ modulator, the radio frequency configuration module comprises a power divider and two electrical filter groups; the power divider is connected with the amplifier and is used for dividing the power of the amplified electric signal; one of the electric filter groups includes a first electric filter and a second electric filter, the other electric filter group 132 includes a third electric filter and a fourth electric filter, and the first electric filter, the second electric filter, and the third electric filter and the fourth electric filter are connected to the power divider. The first electric filter is used for carrying out frequency selection on the electric signal according to a first preset frequency to obtain a first radio frequency signal f1; the second electric filter is used for carrying out frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal f2; the first and second electric filters are also connected to a controlled end of an IQ modulator, and the IQ modulator is further configured to couple the first radio frequency signal f1 and the second radio frequency signal f2 to two sides of a sideband in the X polarization state of the optical carrier fc, respectively, to obtain two frequency optical local oscillation signals fc-f1, fc+f2 in the X polarization state. The third electric filter is used for carrying out frequency selection on the electric signal according to a third preset frequency to obtain a third radio frequency signal f3; the fourth electric filter is used for carrying out frequency selection on the electric signal according to a fourth preset frequency to obtain a fourth radio frequency signal f4; the third and fourth electric filters are also connected with the controlled end of another IQ modulator, and the other IQ modulator is further configured to couple the third radio frequency signal f3 and the fourth radio frequency signal f4 to two sides of the sidebands on the Y polarization state of the optical carrier fc respectively, so as to obtain two frequency optical local oscillation signals fc-f4 and fc+f3 on the Y polarization state.

It should be noted that, for convenience and brevity of description, specific working processes of the above-described multi-frequency optical local oscillation generating method may refer to corresponding processes in the embodiments of the multi-frequency optical local oscillation generating apparatus in fig. 1 to 7, and are not described herein.

According to the multi-frequency optical local oscillation generating method provided by the embodiment, the IQ modulator is used for carrying out quadrature modulation on the optical carrier wave output by the laser source to obtain a modulated optical signal; converting the modulated optical signal into an electrical signal by a photoelectric conversion module; the method comprises the steps that an electric signal is configured into a plurality of radio frequency signals with preset frequencies through a radio frequency configuration module; and coupling the plurality of radio frequency signals with the optical carrier wave respectively through an IQ modulator to obtain the multi-frequency optical local oscillation signal. According to the embodiment of the application, the IQ modulator is used for coupling the radio frequency signals with the preset frequencies with the optical carrier, so that sideband multiplexing of the local oscillation frequency is realized, the optical local oscillation signals with multiple frequency bands can be obtained in a high cost performance mode, the cost for generating the multi-frequency optical local oscillation is effectively reduced, and the frequency spectrum utilization rate is improved.

Referring to fig. 9, fig. 9 is a schematic block diagram of a communication system according to an embodiment of the present application.

As shown in fig. 9, the communication system 300 includes a transmitting link 310, a receiving link 320, and a multi-frequency optical local oscillator generating device 330, where the multi-frequency optical local oscillator generating device 330 is configured to provide multi-frequency optical local oscillator signals for the transmitting link 310 and the receiving link 320. The multi-frequency optical local oscillation generating device 330 may be respectively connected to the transmitting link 310 and the receiving link 320, so as to send multi-frequency optical local oscillation signals to the transmitting link 310 and the receiving link 320, respectively. The multi-frequency optical local oscillation generating device 330 may be the multi-frequency optical local oscillation generating device 100 of fig. 1 to 7 in the foregoing embodiments.

It should be noted that, in the multi-band microwave photon communication process, the transmitting link 310 and the receiving link 320 may share the multi-band optical local oscillator generating device 330, so that multi-band microwave photon communication can be conveniently and quickly implemented, that is, the multi-band radio frequency signal is sent out through the transmitting link 310, or the multi-band target baseband data signal is received through the receiving link 320.

In one embodiment, as shown in fig. 10, the transmitting chain 310 includes a transmitting-end IQ modulator 311, a second filter bank 312, and a first photodetector bank 313; the transmitting-end IQ modulator 311 is configured to be connected to the laser source 10, and further configured to receive a baseband data signal, so as to modulate the baseband data signal on an optical carrier output by the laser source 10, thereby obtaining a baseband modulated signal; the multi-frequency optical local oscillation signal provided by the multi-frequency optical local oscillation generating device 330 is used for coupling with a baseband modulation signal to obtain a multi-frequency baseband coupling signal; the second filter bank 312 is connected to the transmitting end IQ modulator 311 and the multi-frequency optical local oscillation generating device 330, and the second filter bank 312 is used for filtering the multi-frequency baseband coupling signal; the first photodetector bank 313 is connected to the second filter bank 312, and is configured to heterodyne the filtered multi-band baseband coupled signal to output a multi-band rf signal Tx.

In an embodiment, as shown in fig. 10 and 11, the transmission link 310 further includes a second polarization controller 3141 and a third polarization beam splitter 3142; the output end of the second polarization controller 3141 is connected to the transmitting end IQ modulator 311 and the multi-frequency optical local oscillation generating device 330, and the second polarization controller 3141 is configured to control the third polarization beam splitter 3142 according to the polarization state angle of the first polarization beam splitter 1141 or the second polarization beam splitter 1242 in the multi-frequency optical local oscillation generating device 330, so that the polarization state angles of the third polarization beam splitter 3142 and the first polarization beam splitter 1141 or the second polarization beam splitter 1242 are kept the same; the third polarization beam splitter 3142 is connected to the second polarization controller 3141, and the third polarization beam splitter 3142 is configured to split the polarization state signal of the multi-frequency baseband coupling signal and input the split multi-frequency baseband coupling signal to the second filter bank 312.

The second filter bank 312 includes, for example, an optical filter 3121, an optical filter 3122, an optical filter 3123, and an optical filter 3124, and the first photodetector bank 313 includes a photodetector 3131, a photodetector 3132, a photodetector 3133, and a photodetector 3134. The optical filter 3121 is connected to the photo detector 3131, the optical filter 3121 is configured to filter the separated baseband coupling signal according to the first preset frequency, and the photo detector 3131 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain the radio frequency signal f1. The optical filter 3122 is connected to the photo detector 3132, the optical filter 3122 is configured to filter the separated baseband coupling signal according to the second preset frequency, and the photo detector 3132 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain the radio frequency signal f2. The optical filter 3123 is connected to the photo detector 3133, the optical filter 3123 is configured to filter the separated baseband coupling signal according to the third preset frequency, and the photo detector 3133 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain the radio frequency signal f3. The optical filter 3124 is connected to the photodetector 3134, the optical filter 3124 is configured to filter the separated baseband coupling signal according to the fourth preset frequency, and the photodetector 3134 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain the radio frequency signal f4.

It should be noted that, for the transmitting link 310, the optical carrier fc generated by the laser source modulates the baseband data signal generated by the digital-to-analog converter through an transmitting end IQ modulator (MZM), and the modulated baseband modulated signal is then coupled to the optical local oscillation signal generated by the multi-frequency optical local oscillation module, and transmitted to the far-end polarization controller, so that the two orthogonal polarization states of X, Y are separated at the two output ends of the polarization beam splitter by adjusting the polarization controller. For the X polarization state, the output optical signal comprises two optical local oscillators (fc-f 1 and fc+f2) in the X polarization state and a baseband signal modulated on an optical carrier fc, after the two optical filters are used for filtering left and right sidebands respectively, one of the filtered signals is used for filtering the baseband signal at the optical local oscillator fc-f1 and the optical carrier fc, and the other is used for filtering the baseband signal at the optical local oscillator fc+f2 and the optical carrier fc, and after heterodyne beat frequencies of the two signals are respectively used for the photoelectric detector, conversion from the baseband signal to two radio frequency signals Tx with the center frequencies f1 and f2 can be realized; similarly, for the Y polarization state, the output optical signal includes two optical local oscillators (fc+f3, fc-f 4) in the Y polarization state and a baseband signal modulated on the optical carrier fc, and then is divided into two paths, each path is passed through an optical filter, one filters out the baseband signals at the optical local oscillator fc+f3 and the optical carrier fc, and the other filters out the baseband signals at the optical local oscillator fc-f4 and the optical carrier fc, and after heterodyning of the optical detector, two radio frequency signals Tx with center frequencies f3 and f4 can be obtained. Thereby, band transmission of four frequency bands such as (fc-f 1, fc) (fc, fc+f2) (fc-f 4, fc) (fc, fc+f3) can be achieved.

In one embodiment, as shown in fig. 10, the receiving link 320 includes a receiving end IQ modulator 321, a third filter bank 322, and a second photodetector bank 323; the receiving-end IQ modulator 321 is configured to be connected to the laser source 10, and further configured to receive the multi-band rf signal received by the antenna, so as to modulate the multi-band rf signal on an optical carrier output by the laser source 10, thereby obtaining a multi-band rf modulated signal; the multi-frequency optical local oscillation signal provided by the multi-frequency optical local oscillation generating device is used for coupling with the multi-frequency band radio frequency modulation signal to obtain a multi-frequency band radio frequency coupling signal; the third filter bank 322 is connected with the receiving end IQ modulator 321 and the multi-frequency optical local oscillation generating device, and the third filter bank 322 is used for filtering the multi-frequency band radio frequency coupling signal; the second photodetector group 323 is connected to the third filter group 322, and is configured to heterodyne the filtered multiband rf coupled signal to obtain a multiband target baseband data signal.

In one embodiment, as shown in fig. 10 and 11, the receiving link 320 further includes a second photodetector group 3241 and a fourth polarizing beamsplitter 3242; the output end of the second photoelectric detector set 3241 is connected to the receiving end IQ modulator 321 and the multi-frequency optical local oscillation generating device 330, and the second photoelectric detector set 3241 is configured to control the fourth polarizing beam splitter 3242 according to the polarization state angle of the first polarizing beam splitter 1141 or the second polarizing beam splitter 1242 in the multi-frequency optical local oscillation generating device 330, so that the polarization state angles of the fourth polarizing beam splitter 3242 and the first polarizing beam splitter 1141 or the second polarizing beam splitter 1242 are kept the same; the fourth polarizing beam splitter 3242 is connected to the second photodetector group 3241, and the fourth polarizing beam splitter 3242 is configured to split the polarized signal from the multiband rf coupling signal and input the split multiband rf coupling signal to the third filter group 322.

The third filter group 322 includes an optical filter 3221, an optical filter 3222, an optical filter 3223, and an optical filter 3224, and the second photodetector group 323 includes a photodetector 3231, a photodetector 3232, a photodetector 3233, and a photodetector 3234, for example. The optical filter 3221 is connected to the photodetector 3231, the optical filter 3221 is configured to filter the separated baseband coupling signal according to a first preset frequency, and the photodetector 3231 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain a radio frequency signal f1. The optical filter 3222 is connected to the photodetector 3232, the optical filter 3222 is configured to filter the separated baseband coupling signal according to the second preset frequency, and the photodetector 3232 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain a radio frequency signal f2. The optical filter 3223 is connected to the photodetector 3233, the optical filter 3223 is configured to filter the separated baseband coupling signal according to a third preset frequency, and the photodetector 3233 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain a radio frequency signal f3. The optical filter 3224 is connected to the photodetector 3234, the optical filter 3224 is configured to filter the separated baseband coupling signal according to a fourth preset frequency, and the photodetector 3234 is configured to convert the filtered baseband coupling signal into an optical signal for output, so as to obtain a radio frequency signal f4.

It should be noted that, for the downlink receiving link 320, the optical carrier fc generated by the laser source modulates the multi-band radio frequency signal (the central carrier frequencies are f1, f2, f3, f4 respectively) received by the upper antenna Rx through a receiving end IQ modulator (MZM), and makes the receiving end IQ modulator work in a carrier suppression double-sideband modulation mode, so that there are multi-band radio frequency modulation signals on both left and right sides of the optical carrier, and the central carrier frequency of the left side optical carrier multi-band radio frequency modulation signal may be expressed as: the center carrier frequency of the fc-f1, fc-f2, fc-f3, fc-f4, right-hand side optical carrier multi-band radio frequency modulated signal may be expressed as: fc+f1, fc+f2, fc+f3, fc+f4. Then, the optical carrier multiband radio frequency modulation signal and the optical local oscillation signal generated by the multiband optical local oscillation module are coupled together, are sent into a polarization controller, and are separated into X, Y two orthogonal polarization states through a polarization beam splitter. For the X polarization state, the output optical signals comprise two optical local oscillation signals (fc-f 1 and fc+f2) in the X polarization state and a multi-frequency band radio frequency signal modulated on the left side and the right side of an optical carrier wave fc, after the left side and the right side of the optical carrier wave fc are respectively filtered through two optical filters, one of the filtered signals optical local oscillation fc-f1 and the radio frequency modulation signal with the central carrier frequency fc-f1 on the left side of the optical carrier wave, the other one of the filtered signals optical local oscillation fc+f2 and the radio frequency modulation signal with the central carrier frequency fc+f2 on the right side of the optical carrier wave are respectively subjected to heterodyne beat frequency of a photoelectric detector, and then conversion from the two radio frequency signals to baseband signals can be realized; for the receiving process in the Y polarization state, the same principle as that of the X polarization state is not described here, and the optical local oscillation signals such as (fc-f 3, fc+f4) are output.

In summary, the proposed transmitting chain 310, receiving chain 320 and multi-frequency optical local oscillator signal generating apparatus 330 can be utilized to simultaneously realize the transmission and reception of four different carrier frequency signals. It can be seen that the communication system provided by the application has simple structure, the frequency of each wave band can be independently adjusted, the flexibility is high, and the practicability is strong.

It should be noted that, for convenience and brevity of description, the specific operation of the above-described communication system may refer to the corresponding process in the embodiment of the multi-frequency optical local oscillation generating device in fig. 1 to 7, which is not described herein.

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, functional modules/units in the apparatus, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between the functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed cooperatively by several physical components. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

The foregoing embodiment numbers of the present application are merely for the purpose of description, and do not represent the advantages or disadvantages of the embodiments. The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any equivalent modifications or substitutions will be apparent to those skilled in the art within the scope of the present application, which is therefore intended to be covered by the present application, and the scope of the present application shall be defined by the appended claims.

Claims

1. A multi-frequency optical local oscillator generation device, comprising:

The photoelectric conversion module is connected with the carrier modulation module and used for converting the modulated optical signals into electric signals;

The radio frequency configuration module is connected with the photoelectric conversion module and is used for configuring the electric signals into radio frequency signals with a plurality of preset frequencies;

2. The multi-frequency optical local oscillation generating apparatus according to claim 1, wherein the carrier modulation module further comprises a single mode optical fiber; the single-mode fiber is connected with the IQ modulator and is used for delaying the modulated optical signal output by the IQ modulator.

3. The apparatus of claim 1, wherein the IQ modulators are plural, and the carrier modulation module further comprises a coupler;

The coupler is connected with the IQ modulators and is used for coupling the modulated optical signals output by the IQ modulators.

4. The multi-frequency optical local oscillation generating apparatus according to claim 3, wherein the photoelectric conversion module comprises a beam splitter, a plurality of photodetectors, and a plurality of amplifiers;

The beam splitter is connected with the coupler and is used for dividing the coupled modulated optical signals into a plurality of sub-modulated optical signals and respectively outputting the sub-modulated optical signals to the plurality of photodetectors;

Each photoelectric detector is connected with the beam splitter and is used for converting the sub-modulated optical signals into sub-electrical signals;

Each amplifier is connected with a plurality of photoelectric detectors in a one-to-one correspondence manner, and the amplifiers are used for amplifying the sub-electrical signals;

Each amplifier is also connected with a plurality of radio frequency configuration modules in a one-to-one correspondence manner, and the radio frequency configuration modules are used for configuring the amplified sub-electrical signals into radio frequency signals with preset frequencies.

5. The multi-frequency optical local oscillation generating apparatus according to claim 1, wherein the IQ modulator comprises a first IQ modulator and a second IQ modulator, and the carrier modulation module further comprises a first polarization beam splitter and a first polarization beam combiner;

The first polarization beam splitter is connected with the laser source and is used for dividing the optical carrier into a first polarization state signal and a second polarization state signal;

The first IQ modulator is connected with the first polarization beam splitter and is used for quadrature modulating the first polarization state signal to obtain a first modulated optical signal;

The second IQ modulator is connected with the first polarization beam splitter and is used for quadrature modulating the second polarization state signal to obtain a second modulated optical signal;

The polarization beam combiner is connected with the first IQ modulator and the second IQ modulator and is used for combining the first modulated optical signal and the second modulated optical signal to obtain the modulated optical signal.

6. The apparatus according to claim 5, wherein the photoelectric conversion module includes a first polarization controller, a second polarization beam splitter, a first photoelectric conversion unit, and a second photoelectric conversion unit;

the first polarization controller is connected with the first polarization beam combiner, and is used for controlling the second polarization beam splitter according to the polarization state angle of the first polarization beam splitter so as to keep the polarization state angles of the second polarization beam splitter and the first polarization beam splitter the same;

the second polarization beam splitter is connected with the first polarization controller and is used for dividing the modulated optical signal into a third polarization state signal and a fourth polarization state signal;

The first photoelectric conversion unit and the second photoelectric conversion unit are connected with the second polarization beam splitter, the first photoelectric conversion unit is used for converting the third polarization state signal into a first electric signal, and the second photoelectric conversion unit is used for converting the fourth polarization state signal into a second electric signal;

The first photoelectric conversion unit and the second photoelectric conversion unit are also connected with the radio frequency configuration module, and the radio frequency configuration module is used for respectively configuring the first electric signal and the second electric signal into radio frequency signals with two preset frequencies.

7. The multi-frequency optical local oscillation generating apparatus according to claim 1, wherein the photoelectric conversion module comprises a photodetector and an amplifier;

The photoelectric detector is connected with the carrier modulation module and is used for converting the modulated optical signals into electric signals;

the amplifier is connected with the photoelectric detector and is used for amplifying the electric signal.

8. The apparatus according to any one of claims 1 to 7, wherein the radio frequency configuration module includes a power divider and a first filter bank;

The power divider is connected with the photoelectric conversion module and is used for distributing power of the electric signals;

the first filter bank is connected with the power divider and is used for carrying out frequency selection on the electric signals to obtain a plurality of radio frequency signals with preset frequencies.

9. The multi-frequency optical local oscillation generating apparatus according to claim 8, wherein the first filter bank includes a first electric filter and a second electric filter, the first electric filter and the second electric filter being connected to the power divider;

The first electric filter is used for selecting the frequency of the electric signal according to a first preset frequency to obtain a first radio frequency signal; the second electric filter is used for carrying out frequency selection on the electric signal according to a second preset frequency to obtain a second radio frequency signal;

the first electric filter and the second electric filter are also connected with a controlled end of the IQ modulator, and the IQ modulator is also used for respectively coupling the first radio frequency signal and the second radio frequency signal to two sides of a sideband of the optical carrier wave to obtain two-frequency optical local oscillation signals.

10. The multi-frequency optical local oscillator generating method is characterized by being applied to a multi-frequency optical local oscillator generating device, wherein the multi-frequency optical local oscillator generating device comprises a carrier modulation module, a photoelectric conversion module and a radio frequency configuration module; the carrier modulation module comprises an in-phase quadrature (IQ) modulator, and the IQ modulator is used for being connected with a laser source; the photoelectric conversion module is connected with the carrier modulation module, the radio frequency configuration module is connected with the photoelectric conversion module, and the IQ modulator is also connected with the radio frequency configuration module; the method comprises the following steps:

Quadrature modulation is carried out on the optical carrier wave output by the laser source through the IQ modulator, so as to obtain a modulated optical signal;

Converting the modulated optical signal into an electrical signal by the photoelectric conversion module;

configuring the electric signals into a plurality of radio frequency signals with preset frequencies through the radio frequency configuration module;

and respectively coupling a plurality of radio frequency signals with the optical carrier wave through the IQ modulator to obtain a multi-frequency optical local oscillation signal.

11. A communication system, comprising:

a transmit link and a receive link; and

A multi-frequency optical local oscillator generation apparatus as claimed in any one of claims 1 to 9, for providing multi-frequency optical local oscillator signals to the transmit chain and the receive chain.

12. The communication system of claim 11, wherein the transmit chain comprises a transmit-side IQ modulator, a second filter bank, and a first photodetector bank;

The transmitting end IQ modulator is used for connecting a laser source and also used for receiving a baseband data signal so as to modulate the baseband data signal on an optical carrier wave output by the laser source to obtain a baseband modulation signal; the multi-frequency optical local oscillation signal provided by the multi-frequency optical local oscillation generating device is used for coupling with the baseband modulation signal to obtain a multi-frequency baseband coupling signal;

the second filter bank is connected with the transmitting end IQ modulator and the multi-frequency optical local oscillation generating device and is used for filtering the multi-frequency baseband coupling signals;

The first photoelectric detector group is connected with the second filter group and is used for heterodyning the filtered multi-frequency baseband coupling signals so as to output multi-frequency-band radio frequency signals.

13. The communication system of claim 12, wherein the transmit chain further comprises a second polarization controller and a third polarization splitter;

the output end of the second polarization controller is connected with the transmitting end IQ modulator and the multi-frequency optical local oscillation generating device, and the second polarization controller is used for controlling the third polarization beam splitter according to the polarization state angle of the first polarization beam splitter or the second polarization beam splitter in the multi-frequency optical local oscillation generating device so as to keep the polarization state angle of the third polarization beam splitter and the polarization state angle of the first polarization beam splitter or the second polarization beam splitter to be the same;

The third polarization beam splitter is connected with the second polarization controller, and is used for separating the polarization state signals of the multi-frequency baseband coupling signals and inputting the separated multi-frequency baseband coupling signals into the second filter bank.

14. The communication system of claim 11, wherein the receive chain comprises a receive-side IQ modulator, a third filter bank, and a second photodetector bank;

The receiving end IQ modulator is used for being connected with a laser source and is also used for receiving the multi-band radio frequency signals received by the antenna so as to modulate the multi-band radio frequency signals on an optical carrier wave output by the laser source to obtain multi-band radio frequency modulation signals; the multi-frequency optical local oscillation signal provided by the multi-frequency optical local oscillation generating device is used for coupling with the multi-frequency band radio frequency modulation signal to obtain a multi-frequency band radio frequency coupling signal;

the third filter bank is connected with the receiving end IQ modulator and the multi-frequency optical local oscillator generating device and is used for filtering the multi-frequency band radio frequency coupling signal;

The second photoelectric detector group is connected with the third filter group and is used for heterodyning the filtered multi-band radio frequency coupling signals to obtain multi-band target baseband data signals.

15. The communication system of claim 14, wherein the receive chain further comprises a third polarization controller and a fourth polarization splitter;

the output end of the third polarization controller is connected with the receiving end IQ modulator and the multi-frequency optical local oscillation generating device, and the third polarization controller is used for controlling the fourth polarization beam splitter according to the polarization state angle of the first polarization beam splitter or the second polarization beam splitter in the multi-frequency optical local oscillation generating device so as to keep the polarization state angle of the fourth polarization beam splitter and the polarization state angle of the first polarization beam splitter or the second polarization beam splitter to be the same;

The fourth polarization beam splitter is connected with the third polarization controller, and is used for separating the polarization state signals of the multi-band radio frequency coupling signals and inputting the separated multi-band radio frequency coupling signals into the third filter bank.