Multi-channel radio frequency signal stable-phase optical fiber transmission system and method

Abstract

The invention relates to the technical field of optical communication, in particular to a multi-channel radio frequency signal stable-phase optical fiber transmission system and method. Pilot signals and multi-path radio frequency signals are converted into multi-path optical signals through electro-optical conversion, then combined into one path of optical signals through dense wavelength division multiplexing, transmitted to the radio frequency signal receiver through optical fibers, decomposed into multi-path optical signals after wavelength division demultiplexing, and subjected to photoelectric conversion to recover pilot signals and multi-path radio frequency signals; the pilot signal is used for extracting a phase difference variable quantity, the phase measurement control module is used for carrying out phase discrimination measurement on the phase of the received pilot signal, the variable quantity of the phase is calculated to control the adjustable optical delay line, and the phase compensation of multiple paths of radio frequency signals is finally completed by changing the time delay of an optical fiber link. Therefore, multi-channel radio-frequency signal stable-phase optical fiber transmission is realized.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a multi-channel radio frequency signal phase-stable optical fiber transmission system and method. Background Art

[0002] RF signal optical fiber transmission technology is one of the important application directions of microwave photonics. It is a communication method that combines optical communication technology and microwave technology. Optical fiber transmission has many excellent characteristics such as long transmission distance, low loss, wide bandwidth, fast speed, high cost performance, low impact of electromagnetic interference, and flexible mobile deployment. It has very broad application prospects in many fields such as communication, electronic reconnaissance, electronic countermeasures, satellite ground stations, aerospace, etc. Especially in ground-based vehicle-mounted phased array radars and distributed radars, the RF signal is transmitted and processed remotely through optical fiber, and the complex signal processing equipment can be moved to the back end to reduce the size, weight and power consumption of the front-end equipment, which greatly improves the maintainability and reliability of the product. However, in the RF signal optical fiber transmission link, the optical cable transmission line is a long-distance optical fiber, which is easily affected by environmental factors, causing the equivalent length of the optical fiber to change, resulting in changes in the transmission delay, and ultimately causing the RF signal phase deviation.

[0003] Existing RF signal phase-stable optical fiber transmission systems usually use a method that combines phase measurement and delay measurement. Generally, the delay of the round-trip optical fiber and the phase difference of the round-trip pilot signal are measured, and then the change in the optical signal delay corresponding to the phase change of the RF signal is calculated or the measured delay is used to adjust the delay line of the link to compensate for the optical fiber link delay, thereby achieving stable transmission of the RF signal phase. However, these methods are only applicable to single-channel RF signals or when real-time transmission requirements are not high, because this method requires collecting the round-trip optical signal and obtaining the phase change based on a certain algorithm to control the optical fiber link delay. This feedback control has a certain delay and is limited by the bandwidth of the high-frequency phase detector, and cannot take into account the current application requirements of long distance, real-time, high frequency band, and large bandwidth. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-channel RF signal phase-stable optical fiber transmission system and method, aiming to achieve the application requirements of RF phase-stabilization technology for long distance, real-time, high frequency band and large bandwidth.

[0005] To achieve the above-mentioned object, the present invention provides a multi-channel RF signal phase-stable optical fiber transmission system, comprising an RF signal transmitter and an RF signal receiver, wherein the output end of the RF signal transmitter is connected to the input end of the RF signal receiver via an optical fiber, the RF signal transmitter is used to convert the RF signal and the pilot signal transmitted in the optical fiber link into an optical signal, and the RF signal receiver is used to receive the optical signal of the optical fiber link carrying the RF signal and the pilot signal;

[0006] The radio frequency signal transmitter includes a standard frequency signal source, a 1-to-N power splitter, a dense wavelength division multiplexer and a radio frequency electro-optical preprocessing component, the radio frequency electro-optical preprocessing component includes at least two radio frequency electro-optical preprocessing units, the radio frequency electro-optical preprocessing component also includes a radio frequency signal device, a combiner, and an electro-optical conversion module, the output end of the radio frequency signal device is electrically connected to an input end of the combiner, the output end of the standard frequency signal source is electrically connected to the input end of the 1-to-N power splitter, the output end of the 1-to-N power splitter is electrically connected to the other input end of the combiner, the output end of the combiner is electrically connected to the input end of the electro-optical conversion module, and the electro-optical conversion module and the dense wavelength division multiplexer unit are connected by optical fiber;

[0007] The pilot signal divided by the 1-to-N power divider and the first radio frequency signal output by the radio frequency signal device are respectively combined into a second radio frequency signal through a combiner.

[0008] Among them, the radio frequency signal receiver includes a de-wavelength division multiplexer, an optical fiber delay line group, an radio frequency optoelectronic preprocessing unit and a phase detection processing group. The optical fiber delay line group includes at least two adjustable optical fiber delay lines. The input end of the de-wavelength division multiplexer is connected to the output end of the radio frequency signal transmitter through a transmission optical cable. The de-wavelength division multiplexer, the optical fiber delay line group, and the radio frequency optoelectronic preprocessing unit are connected in sequence through optical fibers. The output end of the radio frequency optoelectronic preprocessing unit is respectively connected to the input end of the phase detection processing group and the phase-stable output radio frequency signal end.

[0009] Among them, the RF optoelectronic preprocessing unit includes at least two RF optoelectronic preprocessing modules, and the RF optoelectronic preprocessing module includes an optoelectronic conversion module and a power division filter component. The input end of the optoelectronic conversion module is connected to the output end of the adjustable optical fiber delay line, and the output end of the optoelectronic conversion module is connected to the input end of the power division filter component. The output end of the power division filter component is respectively connected to the input end of the phase detection processing group and the phase-stable output RF signal end. The second RF signal is divided into one RF signal and N+1 pilot reference signals through the power division filter component.

[0010] Wherein, the phase-detection processing group includes at least two phase detectors, and the phase-detection processing group includes a phase-detection measurement control module and a phase detector. N pilot signals output by one of the power division and filtering components are respectively transmitted to one input end of the N phase detectors, and one pilot signal output by the remaining N-1 power division and filtering components is respectively transmitted to another input end of the N-1 phase detectors. The output end of the phase detector is connected to the input end of the phase-detection measurement control module, and the output end of the phase-detection measurement control module is connected to the delay adjustment input end of the adjustable optical fiber delay line.

[0011] The present invention also proposes a multi-channel radio frequency signal phase-stable optical fiber transmission method, using the multi-channel radio frequency signal phase-stable optical fiber transmission system, comprising the following steps:

[0012] Step 1: After demultiplexing the optical signal received by the wavelength division multiplexer, it separates the optical signal into N optical signals and connects them to fixed λ1, λ2…λ at a certain wavelength interval. N In the wavelength channel;

[0013] Step 2: Obtain the converted optical signal in the optical fiber transmission link, where the converted optical signal is a signal obtained by combining the radio frequency signal and the pilot signal through a radio frequency signal transmitter;

[0014] Step 3: Separate the optical signal into N RF signals and N pilot reference signals through the signal RF optoelectronic preprocessing unit;

[0015] Step 4: Send the pilot reference signal to the phase detection processing group to obtain a phase error control signal;

[0016] Step 5: According to the phase error control signal, the real-time delay time of the optical fiber delay line is adjusted to achieve phase-stable transmission of the RF signal.

[0017] Optionally, the real-time delay time in step 5 is linearly related to the RF phase, and the expression is as follows:

[0018]

[0019] in, is the phase, τ is the real-time delay time, f is the transmission frequency, Δλ is the difference between the optical wavelength of the defined initial phase reference channel and the optical wavelength of the N-1 channel, λ is the optical wavelength of the initial phase reference channel. For a given transmission frequency f and channel wavelength λ, the real-time delay time τ and phase There is a linear relationship.

[0020] The present invention provides a multi-channel radio frequency signal phase-stable optical fiber transmission system and method. There is no need to use round-trip optical signals to measure the time delay of an optical fiber link. Multi-channel radio frequency signals and pilot reference signals are modulated onto optical signals respectively through dense wavelength division multiplexing technology, and transmitted to the radio frequency signal receiver through an optical fiber. Phase comparison is performed through the phase detector to generate a phase difference variation. The phase difference variation is used to control an electrically controlled adjustable optical fiber delay line in the optical fiber link to achieve phase consistency of N-channel radio frequency signals. In the process of extracting the phase difference variation, the pilot reference signal of the power division filter component is taken as the Nth pilot signal output by one of the power division filter components, and is respectively transmitted to an input end of the Nth phase detector, and the pilot signal is used as the reference phase initial value of the phase correction signal. The remaining N-1 power division filter components output one pilot signal and transmit it to the other input end of the N-1 phase detectors to compare the deviation with the reference phase initial value, and then obtain the deviation. The signal of the deviation is output to the adjustable optical fiber delay line as the phase difference variation. The phase of the second radio frequency signal is adjusted by the phase difference variation control signal, so as to realize the phase-stable optical fiber transmission of N radio frequency signals. Before the signal in the optical fiber transmission link is subjected to the phase-stable control, a series of conversion, matching, optical path adaptation, amplification and other operations are performed on the signal, and multiple radio frequency signals are transmitted through one core optical fiber, and the stability of phase transmission can be guaranteed, which solves the problem that the existing radio frequency phase-stabilization technology is not compatible with real-time, high frequency band and large bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the architecture of a multi-channel radio frequency signal phase-stable optical fiber transmission system of the present invention.

[0023] Figure 2 The present invention is a schematic diagram of the composition principle of a radio frequency optoelectronic preprocessing unit of a multi-channel radio frequency signal phase-stable optical fiber transmission system.

[0024] Figure 3 It is a flow chart of a multi-channel radio frequency signal phase-stable optical fiber transmission method of the present invention.

[0025] 1-RF signal device, 2-combiner, 3-electro-optical conversion module, 4-standard frequency signal source, 5-1-to-N power splitter, 6-dense wavelength division multiplexer, 7-transmission optical cable, 8-demultiplexer, 9-adjustable optical fiber delay line, 10-photoelectric conversion module, 11-power division filter component, 12-phase detection measurement control module, 13-phase detector, 100-RF signal transmitter, 101-RF electro-optical preprocessing component, 200-RF signal receiver, 201-RF optoelectronic preprocessing unit, 202-phase detection processing group, 203-optical fiber delay line group. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] See also Figure 1 The present invention provides a multi-channel RF signal phase-stable optical fiber transmission system, comprising a RF signal transmitter 100 for converting RF signals and pilot signals in an optical fiber link into optical signals, and a RF signal receiver 200 for receiving optical signals in the optical fiber link carrying RF signals and pilot signals, wherein the output end of the RF signal transmitter 100 is connected to the input end of the RF signal receiver 200 via an optical fiber connection, the RF signal transmitter 100 comprises a standard frequency signal source 4, a 1-to-N power splitter 5, a dense wavelength division multiplexer 6 and a RF electro-optical preprocessing component 101, and the RF electro-optical preprocessing component 101 comprises at least two A radio frequency electro-optical preprocessing unit, the radio frequency electro-optical preprocessing component 101 includes a radio frequency signal device 1, an N-way combiner 2 and an electro-optical conversion module 3, the output end of the radio frequency signal device 1 is electrically connected to an input end of the combiner 2, the output end of the standard frequency signal source 4 is electrically connected to the other input end of the 1-to-N power splitter 5, the output end of the combiner 2 is electrically connected to the input end of the electro-optical conversion module 3, the output end of the electro-optical conversion module 3 is connected to the dense wavelength division multiplexer 6 through an optical fiber, and the output end of the dense wavelength division multiplexer 6 is connected to the input end of the de-wavelength division multiplexer 8 through an optical fiber cable 7. The pilot signal separated by the 1-to-N power splitter 5 and the first radio frequency signal output by the radio frequency signal device 1 are respectively combined into a second radio frequency signal through the combiner 2. The radio frequency signal transmitter 100 converts the electrical signal to be transmitted into an optical signal, and transmits it to the input end of the de-wavelength division multiplexer 8 through the transmission optical cable 7. The combiner 2 combines the pilot signal with different frequencies and the first radio frequency signal into a second radio frequency signal with a certain frequency.

[0028] The RF signal receiver 200 includes a de-wavelength division multiplexer 8, an optical fiber delay line group 203, an RF optoelectronic preprocessing unit 201, and a phase detection processing group 202. The optical fiber delay line group 203 includes at least two adjustable optical fiber delay lines 9. The input end of the de-wavelength division multiplexer 8 is connected to the output end of the RF signal transmitter 100 through an optical fiber. The de-wavelength division multiplexer 8, the optical fiber delay line group 203, and the RF optoelectronic preprocessing unit 201 are connected in sequence through optical fibers. The output end of the RF optoelectronic preprocessing unit 201 is respectively connected to the input end of the phase detection processing group 202 and the phase-stable output RF signal.

[0029] N radio frequency signals and pilot signals in the optical fiber transmission link are combined and converted into optical signals through the radio frequency signal transmitter 100. The N optical signals are multiplexed into one optical signal through the dense wavelength division multiplexer 6 and output to the de-wavelength division multiplexer 8. The optical signals enter the radio frequency optoelectronic preprocessing unit 201 through the adjustable optical fiber delay line 9. The optical signals are converted and separated into N (N is greater than or equal to 2) radio frequency signals and N pilot reference signals through the radio frequency optoelectronic preprocessing unit 201. The N pilot reference signals enter the phase detection processing group 202 to measure, control and adjust the phase to achieve steady-state transmission. Therefore, the adaptive optical fiber transmission device of the present invention achieves steady-state transmission of radio frequency signals in the optical fiber transmission link.

[0030] Furthermore, the RF optoelectronic preprocessing unit 201 includes at least two RF optoelectronic preprocessing modules, and the RF optoelectronic preprocessing module includes an optoelectronic conversion module 10 and a power division filter component 11. The input end of the optoelectronic conversion module 8 is connected to the output end of the adjustable optical fiber delay line 9, and the output end of the optoelectronic conversion module 10 is connected to the input end of the power division filter component 11. The output end of the power division filter component 11 is respectively connected to the input end of the phase detection processing group 202 and the phase-stable output RF signal; the second RF signal is divided into one RF signal and N pilot reference signals through the power division filter component 11. The optical signal transmitted by the optical fiber delay line 9 is integrated by the RF optoelectronic preprocessing unit 201 and separated into a pilot signal and a RF reference signal, and the pilot signal is transmitted to the phase detection processing group 202 to achieve phase-stable transmission. The schematic diagram of the composition principle of the RF optoelectronic preprocessing unit is shown as follows. Figure 2 shown.

[0031] The phase detection processing group 202 includes a phase detector 13 and a phase detection measurement control module 12. N pilot signals output by one of the power division filter components 11 are respectively transmitted to one input end of the N phase detectors 13, and one pilot signal output by the remaining N-1 power division filter components 11 is respectively transmitted to another input end of the N-1 phase detectors 13. The output end of the phase detector 13 is connected to the input end of the phase detection measurement control module 12, and the output end of the phase detection measurement control module 12 is connected to the adjustment input end of the adjustable optical fiber delay line 9. The phase error signal is generated by the introduction of the pilot signal and the measurement of the phase detector 13. The adjustment input end of the adjustable optical fiber delay line 9 receives the phase adjustment signal output by the phase detection measurement control module 12, and the entire optical fiber transmission link is phase compensated to realize the adaptive stable phase transmission of N radio frequency signals.

[0032] like Figure 3 As shown, the present invention also proposes a multi-channel RF signal phase-stable optical fiber transmission method, using the multi-channel RF signal phase-stable optical fiber transmission system, including the following steps:

[0033] S1: After demultiplexing the optical signal received by the wavelength division multiplexer, it separates the optical signal into N optical signals and connects them to fixed λ1, λ2…λ at a certain wavelength interval. N In the wavelength channel;

[0034] S2: Obtaining a converted optical signal in the optical fiber transmission link, where the converted optical signal is a signal obtained by combining the radio frequency signal and the pilot signal through a radio frequency signal transmitter;

[0035] S3: Separate the optical signal into N radio frequency signals and N pilot reference signals through a signal radio frequency optoelectronic preprocessing unit;

[0036] S4: Send the pilot reference signal to the phase detection processing group to obtain a phase error control signal;

[0037] S5: adjusting the real-time delay time of the optical fiber delay line according to the phase error control signal to achieve phase-stable transmission of the radio frequency signal.

[0038] Furthermore, the real-time delay time in step S5 is linearly related to the RF phase, and the expression is as follows:

[0039]

[0040] in, is the phase, τ is the real-time delay time, f is the transmission frequency, Δλ is the difference between the optical wavelength of the defined initial phase reference channel and the optical wavelength of the N-1 channel, λ is the optical wavelength of the initial phase reference channel. For a given transmission frequency f and channel wavelength λ, the real-time delay time τ and phase There is a linear relationship.

[0041] After steps S1 to S5, a phase error control signal is generated by measuring with a phase detector, and the optical fiber delay line in the control link is controlled to achieve phase consistency of N-channel RF signals; thereby achieving adaptive optical fiber phase-stable transmission of multi-channel RF signals.

[0042] The following is further explained in conjunction with detailed execution steps and specific embodiments:

[0043] The step S1 of obtaining the converted optical signal in the optical fiber transmission link includes steps S101 to S103:

[0044] S101: The pilot signal output by the standard frequency signal source is separated into N pilot signals by a 1-to-N power divider, where N is greater than or equal to 2;

[0045] S102: Sending the pilot signal and the first radio frequency signal output by the radio frequency signal device 1 to a combiner to obtain a combined second radio frequency signal;

[0046] The 1-to-N power splitter divides a pilot signal obtained from a standard frequency signal source into N pilot signals, and each of the N pilot signals is respectively combined with the radio frequency signal through a combiner to form a second radio frequency signal. For example, when there are N pilot signals, N radio frequency signal devices output N first radio frequency signals, and each pilot signal is combined with another first radio frequency signal through a combiner to obtain a combined second radio frequency signal, that is, the N pilot signals are respectively combined with the N first radio frequency signals through N combiners to obtain the combined N second radio frequency signals.

[0047] S103: The radio frequency signal is converted into an optical signal through an electro-optical conversion module.

[0048] It is converted into optical signals so that it can be transmitted to the wavelength division multiplexer through the transmission optical cable, shortening the information transmission time and improving the efficiency of information transmission.

[0049] Step S2 is a process of separating the optical signal into N radio frequency signals and N pilot reference signals respectively by the radio frequency optoelectronic preprocessing unit, comprising the following steps:

[0050] S201: Separating the optical signal in step S103 into N optical signals through a wavelength division multiplexer and transmitting them to an adjustable optical delay line, which then transmits one optical signal to an optoelectronic conversion module to convert the optical signal into an electrical signal;

[0051] The photoelectric conversion module converts the optical signal into an electrical signal for corresponding signal processing.

[0052] S202: transmitting the electrical signal to the power division and filtering component to perform power division and filtering on the electrical signal;

[0053] S203: The electrical signal is separated into 1 radio frequency signal and N+1 pilot reference signals.

[0054] Step S3 transmits the pilot reference signal to the phase detection processing group to obtain a phase error control signal, including steps S301 to S303:

[0055] S301: The two pilot reference signals output by one of the power division and filtering components in step S203 are transmitted to the phase detector as the reference signal of the phase correction signal, and then the remaining N-1 pilot signals of the power division and filtering component are respectively input to the remaining N-1 phase detectors, and then the process proceeds to step S303;

[0056] S302: simultaneously transmitting the N-1 pilot reference signals output by the remaining N-1 power division and filtering components to N-1 phase detectors, and proceeding to step S303;

[0057] S303: simultaneously phase-detect the N-1 pilot reference signal and the reference signal of the phase correction signal, output a phase error control signal through the phase detector, and enter step S5;

[0058] The reference signal of the phase correction signal can be the N+1 pilot signals output by any power division filter component, and any one of the remaining N pilot signals is randomly selected and simultaneously input into the phase detector for phase detection to obtain the initial phase. Then, the remaining N-1 pilot signals of the power division filter component are respectively connected to the other input end of the N-1 phase detectors and simultaneously phase-detected with the pilot signals input by the remaining N-1 power division filter components, and the phase parameters of the remaining N-1 pilot signals are obtained at the same time, thereby realizing the simultaneous stable phase transmission of the N second RF signals.

[0059] For example, when the two pilot reference signals of the Nth power division filter component enter the phase detector, and when the pilot signal separated by the power division filter component is selected as the reference signal of the phase correction signal, the two pilot signals can be considered as one pilot reference signal and the other as the reference signal of the phase correction signal. These two signals are phase-detected, and the output phase error is considered to be 0, that is, the initial phase, which is compared with the phase of the remaining N-1 channels after phase detection to obtain N-1 phase error control signals, thereby realizing the adjustment of the N-1 second RF signals and realizing stable phase transmission of optical fiber transmission.

[0060] In step S5, the phase error control signal output by the phase detector is fed back to the adjustable optical fiber delay line through the phase detection measurement control module. The adjustable optical fiber delay line will produce different delays under the action of the phase error control signal. The delay time is linearly corresponding to the phase of the RF signal. The adjustable optical fiber delay line is controlled by feedback to achieve real-time adjustment of the phase of the N-1 second RF signal, thereby achieving adaptive stable phase transmission of N RF signals.

[0061] The present invention proposes a specific embodiment: when there are two optical transmission links, the optical fiber delay line group includes two adjustable optical fiber delay lines, the radio frequency optoelectronic preprocessing unit includes two radio frequency optoelectronic preprocessing modules, and the phase detection processing group is one; the radio frequency signal device outputs two radio frequency signals, and the 1-to-2 power splitter adopts a 1-to-2 power splitter, and the power splitter divides the pilot signal output by the standard frequency signal source into two paths, wherein one first radio frequency signal and one pilot signal are combined into one second radio frequency signal through a combiner, and the other first radio frequency signal and another pilot signal are combined into another second radio frequency signal through another combiner, and the two combined second radio frequency signals are respectively converted into two optical signals through the optoelectronic conversion module 3, and then multiplexed into one optical signal through a dense wavelength division multiplexer and optically transmitted through a transmission optical cable. To the demultiplexer, one optical signal is separated into two optical signals through the demultiplexer, and connected to two adjustable optical fiber delay lines respectively, and then the optical signal is converted into an electrical signal containing one pilot signal and one radio frequency signal through the photoelectric conversion module respectively, and the electrical signal enters the power division filter component. At this time, the two merged second radio frequency signals are again divided into radio frequency signals and pilot signals by the power division filter component. One merged second radio frequency signal corresponds to one radio frequency signal and three pilot signals respectively; the two pilot signals are used as reference signals of the phase correction signal, and the one pilot signal is used as the pilot reference signal of the current path and the reference signal of the phase correction signal to perform phase-stabilization adjustment on the second radio frequency signal. The radio frequency signal is output in a stable phase after adjustment, and the phase-stabilization adjustment process is as follows.

[0062] The process of steady phase adjustment of the pilot signal: the first power division filter component is used as the reference phase initial value, the first power division filter component outputs three pilot signals, two of which define the reference signals of the phase correction signal, and the other is defined as the pilot signal; one pilot signal A enters one input end of the first phase detector as the reference signal of the phase correction signal, and the other pilot signal B enters the other input end of the first phase detector as the pilot signal, and after the phase is extracted by the first phase detector, the initial phase value of the pilot signal of the reference channel is obtained;

[0063] Another pilot signal C enters an input end of the second phase detector as a reference signal of the phase correction signal. One pilot signal D among the three pilot signals output by the second power division filter component is arbitrarily taken and sent to the other input end of the second phase detector. After phase extraction by the second phase detector, the phase error of the pilot signal of the second power division filter component is obtained. The phase error of the second pilot signal and the pilot signal of the reference channel are compared through the phase detection measurement control module to obtain the phase change of the pilot signal. The delay of the adjustable optical fiber delay line is controlled in real time according to the calculated pilot signal phase change. Since the phase of the second radio frequency signal and the real-time delay time are in a linear correspondence, the phase of the radio frequency signal is compensated on the optical path. Therefore, the transmission phase of the second radio frequency signal is adjusted by controlling the delay of the adjustable optical fiber delay line, thereby realizing the phase adjustment of the radio frequency signal to perform phase-stable transmission of multi-channel radio frequency signals.

[0064] When there are 3 to more optical transmission links, the transmission process is the same as that of a 2-channel optical transmission link. The number of the above combiners, electro-optical conversion modules, adjustable optical fiber delay lines, optoelectronic conversion modules, power division filter components, phase detectors and other devices is set according to the number of input channels of the optical transmission link. For example, for an 8-channel optical transmission link, 8 corresponding transmission devices are used to realize signal transmission and processing.

[0065] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A multi-channel radio frequency signal phase-stable optical fiber transmission system, characterized in that: It includes a radio frequency signal transmitter and a radio frequency signal receiver, wherein the output end of the radio frequency signal transmitter is connected to the input end of the radio frequency signal receiver through an optical fiber, the radio frequency signal transmitter is used to convert the radio frequency signal and the pilot signal transmitted in the optical fiber link into an optical signal, and the radio frequency signal receiver is used to receive the optical signal of the optical fiber link carrying the radio frequency signal and the pilot signal; The radio frequency signal transmitter includes a standard frequency signal source, a 1-to-N power splitter, a dense wavelength division multiplexer and a radio frequency electro-optical preprocessing component, the radio frequency electro-optical preprocessing component includes at least two radio frequency electro-optical preprocessing units, the radio frequency electro-optical preprocessing component also includes a radio frequency signal device, a combiner, and an electro-optical conversion module, the output end of the radio frequency signal device is electrically connected to an input end of the combiner, the output end of the standard frequency signal source is electrically connected to the input end of the 1-to-N power splitter, the output end of the 1-to-N power splitter is electrically connected to the other input end of the combiner, the output end of the combiner is electrically connected to the input end of the electro-optical conversion module, and the electro-optical conversion module and the dense wavelength division multiplexer unit are connected by optical fiber; The pilot signal divided by the 1-to-N power divider and the first radio frequency signal output by the radio frequency signal device are respectively combined into a second radio frequency signal through a combiner.

2. The multi-channel RF signal phase-stable optical fiber transmission system according to claim 1, characterized in that: The radio frequency signal receiver includes a wavelength division demultiplexer, an optical fiber delay line group, a radio frequency optoelectronic preprocessing unit and a phase detection processing group. The optical fiber delay line group includes at least two adjustable optical fiber delay lines. The input end of the wavelength division demultiplexer is connected to the output end of the radio frequency signal transmitter through a transmission optical cable. The wavelength division demultiplexer, the optical fiber delay line group and the radio frequency optoelectronic preprocessing unit are connected in sequence through optical fibers. The output end of the radio frequency optoelectronic preprocessing unit is respectively connected to the input end of the phase detection processing group and the phase-stable output radio frequency signal end.

3. The multi-channel RF signal phase-stable optical fiber transmission system according to claim 1, characterized in that: The RF optoelectronic preprocessing unit includes at least two RF optoelectronic preprocessing modules, and the RF optoelectronic preprocessing module includes an optoelectronic conversion module and a power division filter component. The input end of the optoelectronic conversion module is connected to the output end of the adjustable optical fiber delay line, the output end of the optoelectronic conversion module is connected to the input end of the power division filter component, and the output end of the power division filter component is respectively connected to the input end of the phase detection processing group and the phase-stable output RF signal end. The second RF signal is divided into one RF signal and N+1 pilot reference signals through the power division filter component.

4. The multi-channel RF signal phase-stable optical fiber transmission system according to claim 1, characterized in that: The phase-detection processing group includes at least two phase detectors, and the phase-detection processing group includes a phase-detection measurement control module and a phase detector. N pilot signals output by one of the power division and filtering components are respectively transmitted to one input end of the N phase detectors, and one pilot signal output by the remaining N-1 power division and filtering components is respectively transmitted to another input end of the N-1 phase detectors. The output end of the phase detector is connected to the input end of the phase-detection measurement control module, and the output end of the phase-detection measurement control module is connected to the delay adjustment input end of the adjustable optical fiber delay line.

5. A multi-channel radio frequency signal phase-stable optical fiber transmission method, using the multi-channel radio frequency signal phase-stable optical fiber transmission system according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: After demultiplexing the optical signal received by the wavelength division multiplexer, it separates the optical signal into N optical signals and connects them to fixed λ1, λ2…λ at a certain wavelength interval. N In the wavelength channel; Step 2: Obtain the converted optical signal in the optical fiber transmission link, where the converted optical signal is a signal obtained by combining the radio frequency signal and the pilot signal through a radio frequency signal transmitter; Step 3: Separate the optical signal into N RF signals and N pilot reference signals through the signal RF optoelectronic preprocessing unit; Step 4: Send the pilot reference signal to the phase detection processing group to obtain a phase error control signal; Step 5: According to the phase error control signal, the real-time delay time of the optical fiber delay line is adjusted to achieve phase-stable transmission of the RF signal.

6. The method for phase-stable optical fiber transmission of multi-channel radio frequency signals according to claim 5, characterized in that: The real-time delay time in step 5 is linearly related to the RF phase, and the expression is as follows: in, is the phase, τ is the real-time delay time, f is the transmission frequency, Δλ is the difference between the optical wavelength of the defined initial phase reference channel and the optical wavelength of the N-1 channel, λ is the optical wavelength of the initial phase reference channel. For a given transmission frequency f and channel wavelength λ, the real-time delay time τ and phase There is a linear relationship.

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