Additional phase noise degradation suppression device for tree-shaped radio frequency optical fiber transmission network in vibration scene

Abstract

The invention provides an additional phase noise degradation suppression device for a tree-shaped radio frequency optical fiber transmission network in a vibration scene, and aims to solve the problems that the near-end phase noise of a reference / radio frequency signal transmitted by a tree-shaped radio frequency optical fiber transmission distribution network in a current active phased-array antenna array in the vibration scene is seriously raised, the structure of a traditional vibration reduction measure is complex, and the cost is high. And the maintenance interchangeability is poor. An optical fiber phase shift device is introduced after electro-optical conversion, phase disturbance is added to an intensity-modulated radio-over-fiber signal output by a directly modulated laser, and original intensity modulation-direct detection of scattered light field distribution in a radio frequency optical fiber transmission link is changed; especially, the interference effect of a double Rayleigh scattering light field on an optical carrier radio frequency transmission signal light field is destroyed, so that the influence of scattering light enhanced by external vibration on transmission signal light is greatly weakened, and the purpose that a radio frequency optical fiber transmission distribution network can still keep high signal transmission quality in a vibration scene is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of radio frequency technology, and in particular relates to an additional phase noise degradation suppression device for a tree-shaped radio frequency optical fiber transmission network under a vibration scenario. Background Art

[0002] Replacing RF cables with optical fibers to transmit signals can significantly reduce volume and weight. At the same time, since RF optical fiber transmission technology has good electromagnetic compatibility, it is very suitable for signal transmission and distribution scenarios with strong load limits and lightning protection requirements. However, during the manufacturing process of the optical fiber used to transmit signals, the refractive index inside cannot be guaranteed to be evenly distributed. When the optical signal passes through media with different refractive indices during transmission, Rayleigh scattering will occur. In particular, for optical power splitters and optical wiring boxes used in tree-shaped optical fiber transmission and distribution networks, under strong vibration conditions, the pressure changes on optical splitter core parts and optical fibers significantly enhance their Rayleigh scattering effect. Due to the existence of this effect, a mutual conversion channel between the phase change and the intensity change of the optical signal is established, resulting in the introduction of strong additional phase noise of the RF signal after the optical-to-electric conversion and RF amplification of each optical-carrying RF signal distributed through the tree-shaped RF optical fiber transmission network, especially in the phase noise increase in the frequency deviation ≤100kHz segment, which seriously affects the quality of the output signal of each node.

[0003] In order to weaken this influence and make the RF optical fiber transmission link still obtain lower phase noise in the environment of higher vibration level, the conventional practice is to bundle and fix the optical fiber cables in the link; glue and potting the optical fiber inside the optical power splitter and optical wiring box, and even prepare a special vibration reduction structure to protect the entire optical passive transmission distribution network from vibration. However, the above measures increase the complexity of the preparation of optical passive components such as optical fiber cables, optical power splitters, and optical wiring boxes, and increase the weight of the module; at the same time, the introduction of vibration reduction measures increases the difficulty of link maintenance and interchange; in particular, in the process of laying some specific links, due to the limitations of actual usage scenarios, the vibration reduction measures have little effect.

[0004] In summary, RF fiber transmission technology is expected to replace RF cables due to its light weight and anti-electromagnetic interference characteristics, and can be used for RF signal transmission under strict load limits and lightning protection requirements. However, there is an urgent need to find new means to effectively solve the problem of deterioration of output signal quality of the original RF fiber transmission link under strong vibration scenarios, while also being able to do so without increasing structural complexity, losing system maintainability, and harming the aerodynamic performance of the platform. Summary of the invention

[0005] To this end, the present invention proposes an additional phase noise degradation suppression device for a tree-shaped RF optical fiber transmission network under vibration scenarios, aiming to solve the technical problems that the near-end phase noise of the reference / RF signal transmitted in the tree-shaped RF optical fiber transmission distribution network in the current active phased array antenna array is seriously elevated, the traditional vibration reduction measures have complex structures, and the maintenance and interchangeability are poor. By introducing an optical fiber phase shift device after the electro-optical conversion, a phase disturbance is added to the intensity-modulated light-carrying RF signal output by the direct-modulated laser, and the original intensity modulation is changed - the scattered light field distribution in the direct detection RF optical fiber transmission link is changed, especially the interference effect of the double Rayleigh scattered light field on the light-carrying RF transmission signal light field is destroyed, so that the influence of the scattered light enhanced by the external vibration on the transmission signal light is greatly weakened, so as to achieve the purpose of maintaining a high signal transmission quality in the RF optical fiber transmission distribution network under vibration scenarios.

[0006] The present invention only requires adding a first-level optical fiber phase shift device to the cascade position of the electro-optical modulation unit and the optical amplification unit inside the optical transmitter. There is no need to perform structural vibration reduction treatment on the branches of the tree-shaped radio frequency optical fiber transmission distribution network, which will not increase the structural complexity of the entire radio frequency optical fiber transmission distribution network, will not affect its maintainability and interchangeability, and will not damage the aerodynamic performance of the platform.

[0007] The present invention includes a direct-modulated laser, an arbitrary function generator, an optical fiber stretcher, an erbium-doped optical fiber amplifier, a 1:N optical splitter / optical wiring box, N photoelectric detectors and corresponding optical fiber cables, etc. Among them, the radio frequency input end of the direct-modulated laser is connected to the external input reference / radio frequency signal, the optical output end of the direct-modulated laser is connected to the optical input end of the optical fiber stretcher; the radio frequency input end of the optical fiber stretcher is connected to the output end of the arbitrary function generator, the optical output end of the optical fiber stretcher is connected to the optical input end of the erbium-doped optical fiber amplifier; the optical output end of the erbium-doped optical fiber amplifier is connected to the optical input end of the optical splitter / optical wiring box; the i-th (1≤i≤N) optical output end of the optical splitter / optical wiring box is connected to the optical input end of the i-th photoelectric detector. Among them, the directly modulated laser realizes electro-optical conversion, loads the input reference / RF signal onto the optical carrier of the laser, and converts it into an optically carried RF signal output; the fiber stretcher realizes phase perturbation of the optically carried RF signal, and its control input is a low-frequency signal generated by an arbitrary function generator. Under the action of this signal, the fiber stretcher squeezes the optical fiber, which is equivalent to introducing phase modulation into the optically carried RF signal; the function of the erbium-doped fiber amplifier is to amplify the power of the input optical signal to compensate for the branching and insertion loss caused by the optical splitter / optical wiring box; the function of the 1:N optical splitter / optical wiring box is to divide the input 1 optical signal power into N outputs, thereby meeting the requirements of a tree-shaped RF optical fiber transmission and distribution network for transmission and distribution from a central node to N remote nodes; N photodetectors realize photoelectric conversion of N optically carried RF signals, and convert them into N RF signal outputs.

[0008] The RF input end of the directly modulated laser should be connected to the reference or RF signal to be transmitted and distributed through an RF cable; the modulation input end of the optical fiber stretcher should be connected to the output end of the arbitrary function generator through an RF cable; and the output end of the photodetector should output the RF signal after photoelectric conversion to the next level load through an RF cable.

[0009] The optical output end of the direct-modulated laser should be connected to the optical input end of the optical fiber stretcher through a single-mode optical fiber; the optical output end of the optical fiber stretcher should be connected to the optical input end of the erbium-doped fiber amplifier through a single-mode optical fiber; the optical output end of the erbium-doped fiber amplifier should be connected to the optical input end of the 1:N optical splitter / optical wiring box through a single-mode optical fiber; each optical output end of the 1:N optical splitter / optical wiring box is connected to the optical input end of a photodetector through a single-mode optical fiber.

[0010] The directly modulated laser is a DFB type semiconductor laser, the operating wavelength is in the C band, and the modulation mode of the RF signal should be intensity modulation; preferably, the modulation response bandwidth of the laser should be no less than twice the frequency of the RF signal to be transmitted, and the laser output optical power should be no less than 10dBm.

[0011] The optical fiber stretcher should be a fiber stretcher prepared based on the piezoelectric effect, and can stretch or contract the optical fiber under the excitation of an external modulated signal voltage to produce a change in the optical path; preferably, the optical fiber stretcher is prepared by winding the optical fiber around a PZT cylinder.

[0012] The arbitrary function generator should be able to generate arbitrary waveform signals with a frequency in the range of 1kHz to 100MHz, and the signal should have a certain voltage driving capability; preferably, the signal voltage should not be less than 1V.

[0013] The gain of the erbium-doped fiber amplifier is equal to the sum of the branching loss and the insertion loss of the 1:N optical splitter / optical wiring box described therein.

[0014] The photodetector is a PIN type photodetector, and its 3dB response bandwidth should be no less than twice the frequency of the transmitted RF signal; preferably, its 1dB saturation point of input optical power should be no less than 10dBm, and its responsivity should be no less than 0.8A / W.

[0015] The beneficial effects of the present invention are

[0016] 1. The present invention introduces an optical fiber phase shift device after the electro-optical conversion unit of the optical transmitter to change the original intensity modulation and directly detect the scattered light field distribution in the radio frequency optical fiber transmission link, thereby effectively destroying the interference effect of the scattered light field on the signal light in the optical fiber link, so that the influence of the scattered light field enhanced by external vibration in the optical fiber on the signal light is greatly weakened, thereby achieving the purpose of maintaining a high signal transmission quality in the radio frequency optical fiber transmission distribution network under vibration scenarios.

[0017] 2. The present invention only needs to add a first-level optical fiber phase shift device at the cascade position of the electro-optical modulation unit and the optical amplification unit inside the optical transmitter. There is no need to perform structural vibration reduction treatment on each branch of the tree-shaped RF optical fiber transmission distribution network, which will not increase the structural complexity of the entire RF optical fiber transmission distribution network, will not affect its maintainability and interchangeability, and will not damage the aerodynamic performance of the platform.

[0018] 3. The present invention can be widely used in flying platforms such as unmanned aerial vehicles and airships that have strong load restrictions and lightning protection requirements. It is the key to the high-performance transmission and distribution of clock, local oscillator and other reference and radio frequency signals for the active phased array radar payload carried by the above-mentioned platforms. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a block diagram of the present invention.

[0020] Figure 2 Schematic diagram of additional phase noise degradation suppression in tree-shaped RF optical fiber transmission network under vibration scenario. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The present invention provides a tree-shaped radio frequency optical fiber transmission network additional phase noise degradation suppression device under vibration scenarios, which is used to realize the distributed multi-node transmission distribution of reference or radio frequency signals under vibration scenarios, and make the reference or radio frequency signals output by each channel have lower phase noise. Please refer to the attached general principle block diagram of the device. Figure 1 ,include:

[0023] 1—Directly modulated laser, used to modulate the input reference or RF signal onto an optical carrier to produce an intensity modulated optically carried RF signal.

[0024] 2—Fiber stretcher, used to phase modulate the input intensity modulated light-carrying RF signal. Its modulation input is a low-frequency signal generated by an arbitrary function generator. Under the action of this signal, the fiber stretcher stretches or squeezes the optical fiber to achieve the effect of phase disturbance of the input intensity modulated light-carrying RF signal.

[0025] 3—Arbitrary function generator, used to generate low-frequency modulated input signal to the fiber stretcher.

[0026] 4—Erbium-doped fiber amplifier, used to amplify the power of the input optical signal to compensate for the optical branching loss and optical insertion loss introduced by optical branching and optical fiber cable connection in the tree-shaped optical fiber transmission and distribution network.

[0027] 5-1: N optical splitters / optical wiring boxes are used to divide the input 1-channel optical radio frequency signal into N output channels with equal optical power, meeting the requirements of transmission and distribution from a central node to N remote nodes in a tree-shaped radio frequency optical fiber transmission and distribution network.

[0028] 6-1—The first photoelectric detector is used to perform photoelectric conversion on the first optically-carried radio frequency signal in the tree-shaped radio frequency optical fiber transmission distribution network to achieve radio frequency output of the first network remote node.

[0029] 6-N—Nth photoelectric detector, used for photoelectric conversion of the Nth optical radio frequency signal in the tree-shaped radio frequency optical fiber transmission distribution network to achieve radio frequency output of the Nth network remote node.

[0030] 7—RF connection cable, used to connect the reference signal, RF signal and low-frequency modulation signal with the corresponding unit devices, such as Figure 1 Indicated by the black dashed line.

[0031] 8—Single-mode optical fiber, used for optical path connection between functional unit devices in the device provided by the present invention, such as Figure 1 The black implementation is shown.

[0032] Taking the i-th link in the tree-shaped RF optical fiber transmission distribution network as an example, a brief theoretical analysis of link additional phase noise suppression is given from the direct-modulated laser in the RF signal input device to the i-th photodetector in the device outputting the RF signal:

[0033] When the optical signal is transmitted in the optical fiber cable, the entire transmitted light field E tot (L, t) In addition to the useful signal light field E transmitted in the forward direction sig In addition to (L, t), it also includes the additional light field E caused by various scattering effects in the optical fiber. sca (L, t), the three satisfy the following relationship:

[0034] E tot(L,t)=E sig (L,t)+E sca (L,t) (1)

[0035] After the intensity of the direct-modulated laser is modulated, the light field of the signal light can be expressed by the formula:

[0036]

[0037] In the formula, ω c represents the frequency of the optical carrier, ω sig Indicates the frequency of the intensity modulated signal (i.e. the reference signal or RF signal to be transmitted), m A represents the intensity modulation coefficient, φ(t) represents the phase random jitter, α represents the loss coefficient, and L represents the optical fiber length.

[0038] After the intensity modulated optical radio frequency signal is phase perturbed, its optical field can be expressed as:

[0039]

[0040] In the formula, ω mod represents the frequency of the phase perturbation modulation signal (i.e., the signal generated by the arbitrary function generator), m P represents the phase perturbation modulation coefficient.

[0041] Inside the optical fiber, the scattering effect dominated by Rayleigh scattering satisfies the following statistical law:

[0042] <△n(x)△n(x')>=<△n 2 (x)>exp(-|x-x'| / z R ) (4)

[0043] Where △n(x)=n(x)-n avg , which represents the refractive index n(x) of the optical fiber at position x and the average refractive index n avg The difference, z R Represents the coherence length of the refractive index fluctuations.

[0044] If the transmission optical fiber cable is regarded as composed of M segments of tiny optical fibers of equal length and refractive index, the scattered light field generated in the optical fiber can be expressed by the formula:

[0045]

[0046] Where k = n avg ω c / c is the propagation constant and υ is the group velocity.

[0047] Ignoring the nonlinear effects in the erbium-doped fiber amplifier, assuming that the gain of the fiber amplifier is equal to the sum of the branching loss and the insertion loss introduced by the optical splitter / optical wiring box, the influence of the fiber amplifier and the optical splitter / optical wiring box on the optical field can be ignored in the calculation.

[0048] After the signal passes through the i-th photodetector, the output photocurrent obtained can be expressed by the formula:

[0049] i d (t) = ηP tot e -αL [(1+m A cosω sig t) 2 +g(t)+g*(t)] (6)

[0050] Where η represents the detector's responsivity, P tot represents the optical power injected into the detector, and g(t) represents the photocurrent term introduced by the scattered light, which can be expressed by the formula:

[0051]

[0052] The autocorrelation function of the detector output photocurrent is:

[0053] C(t)= d (t)i d (t+τ)> (8)

[0054]

[0055] Where, 2Re<g(t)g*(t+τ)> The autocorrelation function of the photocurrent generated by the scattered light field is as follows:

[0056]

[0057] In the formula f(δ) is a parameter introduced by phase perturbation modulation and can be expressed as: Obviously, f(δ) satisfies f(δ)≤1, and f(δ)=1 if and only if k=0 (ie, there is no phase disturbance modulation).

[0058] According to the Wiener-Khinchin theorem, the autocorrelation function is converted into power spectral density, and it can be concluded that the power spectral density of the detector output signal satisfies the following relationship:

[0059]

[0060] It can be seen from the above formula that the power spectral density of the detector output can be divided into two parts, namely the power spectral density of the signal itself and the noise power spectral density caused by the scattered light field.​ represents the Lorentz noise power spectrum, τ c is the coherence time of the laser. And ξ(Ω), ξ(Ω-ω sig ),ξ(Ω-2ω sig ) represent the DC signal and the frequency ω respectively. sig and frequency is 2ω sig The signal is limited by the detector response bandwidth and the high-frequency component will not be output.

[0061] From the above analysis, it can be seen that when the optical fiber link does not use phase perturbation modulation, f(δ) takes the value of 1, and only the signal intensity modulation exists. After the phase perturbation is introduced, since f(δ)<1, it is equivalent to attenuating the noise power spectrum density to a certain extent. From the above analysis, it can be seen that there must be an optimal modulation coefficient so that the noise power spectrum density of the link is suppressed to the greatest extent, that is, the phase noise value of the output RF signal is the lowest at this time.

[0062] The following is an example of phase noise optimization in a 10GHz RF signal tree-shaped optical fiber transmission distribution network under vibration scenarios. In this example, the direct-modulated laser selects a C-band DFB direct-modulated laser with a modulation bandwidth ≥ 18GHz, with an output optical power of 13dBm and a relative intensity noise ≤ -145dB / Hz; the optical fiber stretcher selects a piezoelectric optical fiber phase modulator based on a PZT structure. Under the action of the modulation signal, the PZT stretches or contracts radially, driving the optical fiber to stretch or contract, causing the optical path to change; the arbitrary function generator generates a phase disturbance modulation signal. In this example, the modulation voltage is 8V, and the generated modulation signal frequencies are 32kHz, 36kHz, 37kHz, 39kHz, 42kHz and 50kHz respectively. The erbium-doped fiber amplifier uses a C-band gain-flattened fiber amplifier, which works in a constant power output mode and the output power is set at 23dBm; the optical splitter uses a 1-to-16PLC optical splitter, whose operating wavelength range is 1260nm to 1650nm and whose insertion loss is 13.5dB; the photodetector is a PIN-type photodetector, whose response bandwidth is ≥20GHz and whose responsivity is ≥0.8 at 10GHz. The vibration conditions applied in this embodiment are certain airborne vibration conditions, and the vibration power spectrum density is 0.02g 2 / Hz(@15Hz~90Hz),0.1g 2 / Hz(@300Hz~1kHz).

[0063] like Figure 2The figure shows the phase noise curves of the RF optical fiber transmission distribution network under static conditions, vibration-no phase disturbance, and vibration-phase disturbance with different modulation frequencies. It can be clearly seen from the figure that the phase noise of the RF optical fiber transmission distribution network at the near frequency offset (frequency offset ≤ 100kHz) of the output 10GHz RF signal under vibration conditions has been significantly deteriorated compared with that under static conditions. Taking the phase noise values ​​at the 1kHz frequency offset and 10kHz frequency offset positions as a comparison, when only the transmitted RF signal is intensity modulated without phase disturbance, the phase noise under vibration conditions is deteriorated by 22dB@1kHz and 16dB@10kHz respectively compared with the phase noise under static conditions. Under vibration conditions, after applying phase disturbance, it can be seen that the phase noise at the near frequency offset of the output RF signal has been suppressed to a certain extent. When the modulation frequency is 37kHz, the best suppression effect is achieved. At this time, the phase noise deterioration under the vibration scenario is only 6dB@1kHz and 4dB@10kHz respectively; compared with the additional phase noise of the output RF signal without phase disturbance, it has been significantly improved.

[0064] So far, the "device for suppressing phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under vibration scenario" of the present invention has been described in detail in combination with the accompanying drawings and theoretical analysis. Based on the above description, those skilled in the art should have a clear understanding of the "device for suppressing phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under vibration scenario" of the present invention.

[0065] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0066] In summary, the present invention introduces a fiber optic phase shifter after the electro-optical conversion unit of the optical transmitter to change the original intensity modulation - directly detect the scattered light field distribution in the RF fiber optic transmission link, thereby effectively destroying the interference effect of the scattered light field in the optical fiber link on the signal light, so that the influence of the scattered light field in the optical fiber enhanced by external vibration on the signal light is greatly weakened, thereby achieving the purpose of maintaining a high signal transmission quality in the RF fiber optic transmission distribution network under vibration scenarios.

[0067] The present invention avoids performing structural vibration reduction treatment on each branch of the tree-shaped radio frequency optical fiber transmission distribution network, does not increase the structural complexity of the entire radio frequency optical fiber transmission distribution network, does not affect its maintenance and interchangeability, and does not damage the aerodynamic performance of the platform.

Claims

1. A device for suppressing additional phase noise degradation in a tree-shaped radio frequency optical fiber transmission network under vibration scenarios, characterized in that: include: Direct-modulated laser, arbitrary function generator, fiber stretcher, erbium-doped fiber amplifier, 1:N optical splitter / optical wiring box, N photodetectors, RF connection cables and optical fiber cables; The optical output end of the directly modulated laser is connected to the optical input end of the optical fiber stretcher, and is used to modulate the input reference or radio frequency signal onto the optical carrier to generate an intensity modulated optically carried radio frequency signal; The radio frequency input end of the optical fiber stretcher is connected to the output end of the arbitrary function generator, and the output end is connected to the optical input end of the erbium-doped fiber amplifier, and is used to phase modulate the input intensity-modulated optical radio frequency signal; The arbitrary function generator is used to generate a low-frequency modulation input signal for the optical fiber stretcher; The optical output end of the erbium-doped fiber amplifier is connected to the optical input end of the 1:N optical splitter / optical wiring box to amplify the power of the input optical signal; The N optical output ends of the N optical splitters / optical wiring boxes are connected to the optical input ends of the corresponding electrical detectors, and are used to equally divide the input optical radio frequency signal into N output paths according to the optical power; The N photoelectric detectors are used to convert N optical radio frequency signals into N radio frequency signals; RF connection cables, used for RF connection between reference signals, RF signals and low-frequency modulation signals and corresponding unit devices; Optical fiber cable is used for optical connection between various functional unit devices.

2. According to the device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under vibration scenarios in claim 1, it is characterized by: The RF input end of the directly modulated laser should be connected to the reference or RF signal to be transmitted and distributed through an RF cable; the modulation input end of the optical fiber stretcher should be connected to the output end of the arbitrary function generator through an RF cable; the output end of the photodetector should output the RF signal after photoelectric conversion to the next level load through an RF cable.

3. According to the device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under a vibration scenario as described in claim 1, it is characterized in that: The optical output end of the direct-modulated laser should be connected to the optical input end of the optical fiber stretcher through a single-mode optical fiber; the optical output end of the optical fiber stretcher should be connected to the optical input end of the erbium-doped fiber amplifier through a single-mode optical fiber; the optical output end of the erbium-doped fiber amplifier should be connected to the optical input end of the 1:N optical splitter / optical wiring box through a single-mode optical fiber; Each optical output end of the 1:N optical splitter / optical wiring box is connected to the optical input end of a photodetector through a single-mode optical fiber.

4. According to the device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under vibration scenarios in claim 1, it is characterized by: The directly modulated laser is a DFB type semiconductor laser, the operating wavelength is in the C band, and the modulation mode of the radio frequency signal is intensity modulation.

5. According to the device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under a vibration scenario in claim 1, it is characterized in that: The optical fiber stretcher is a fiber stretcher prepared based on the piezoelectric effect, and can stretch or shrink the optical fiber under the excitation of an external modulated signal voltage, thereby causing a change in the optical path.

6. The device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under a vibration scenario according to claim 1, characterized in that: The arbitrary function generator can generate an arbitrary waveform signal with a frequency in the range of 1kHz to 100MHz, and the signal should have a certain voltage driving capability.

7. The device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under a vibration scenario according to claim 1, characterized in that: The gain of the erbium-doped fiber amplifier is equal to the sum of the branching loss and the insertion loss of the 1:N optical splitter / optical wiring box.

8. The device for suppressing additional phase noise degradation of a tree-shaped radio frequency optical fiber transmission network under a vibration scenario according to claim 1, characterized in that: The photoelectric detector is a PIN type photoelectric detector, and its 3dB response bandwidth is not less than twice the frequency of the transmitted radio frequency signal.

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