Bias compensation device for high-power microwave detection system

Abstract

The invention discloses a bias compensation device for a high-power microwave detection system. The bias compensation device is connected with a high-power microwave detector through a second optical fiber. The high-power microwave detector transmits light emitted by the light source to the bias compensation device through a second optical fiber; the bias voltage compensation device adjusts the bias voltage according to external temperature data and a compensation strategy, so that the optical power before temperature change is equal to the optical power after temperature change, and the high-power microwave detector is ensured to be in a stable linear working area. The independent bias compensation device is arranged and connected with the high-power microwave detector through the second optical fiber, optical fiber isolation is achieved, measurement interference of bias voltage on high-power microwaves is eliminated, meanwhile, the bias control device adjusts the bias voltage according to external temperature data, and the measurement accuracy of the high-power microwave detector is improved. The problem of influence of temperature on working point drift of the high-power microwave detector is solved, and the measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field, and in particular to a bias compensation device for a high-power microwave detection system. Background Art

[0002] High-power microwave (HPM) refers to electromagnetic waves with a frequency range of 300MHz-300GHz, a peak power of more than 100MW and an average power of more than 1MW. In the receiving link, high-power microwaves can be instantly coupled into electronic devices through the "front door" and "back door" methods, attacking microelectronic components and their integrated circuits in the form of voltage or current, causing thermal secondary breakdown of PN junctions, and then causing system burnout.

[0003] At present, wireless communication equipment is widely used in national defense and civil communications. Wireless communication equipment is extremely vulnerable to high-power microwave attacks. Although the use of filtering, shielding, limiting and other technologies can effectively reduce electromagnetic interference, the protection effect depends on the frequency and power of microwaves, and it is still passive protection. In the case of various new high-power microwave weapons being demonstrated continuously, in order to ensure that electronic information systems are not damaged in strong electromagnetic environments, it is necessary to actively detect high-power microwaves in order to protect sensitive circuits in the system.

[0004] It has become an effective way to use high-power microwave detectors made of materials with electro-optical modulation effect such as lithium niobate for HPM measurement. The notable features of such high-power microwave detectors include wide bandwidth and fast response, and the photonic link has sufficient electromagnetic interference immunity. However, in high-power microwave scenarios, the electro-optical properties of materials such as lithium niobate will be affected by various factors such as temperature (thermo-optic, thermal expansion and pyroelectricity), mechanical stress and photorefractive index, which will change the working characteristics of high-power microwave detectors. In severe cases, it will cause waveform distortion, thereby affecting the accuracy of measurement. In the prior art, a negative feedback regulation system is usually used to solve the problem of working point drift, that is, to keep the working point of the high-power microwave detector unchanged. In this negative feedback mode, the system usually needs to perform photoelectric conversion, current-voltage conversion, voltage amplification, voltage sampling and laser tuning on the feedback signal at the output end of the detector until the optimal working point is obtained after about 89 cycles. This method makes the negative feedback regulation system complicated and costly, and is not suitable for popularization. Summary of the invention

[0005] The present invention provides a bias compensation device for a high-power microwave detection system, so as to overcome the technical problem that the existing method for solving the working point drift of the high-power microwave detector is complicated and costly.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A bias compensation device for a high-power microwave detection system, the high-power microwave detection system comprising a high-power microwave detector, the bias compensation device being connected to the high-power microwave detector via a second optical fiber;

[0008] The high-power microwave detector transmits the light emitted by the light source to the bias compensation device through the second optical fiber;

[0009] The bias compensation device adjusts the bias voltage according to the external temperature data and the compensation strategy, so that the optical power before the temperature change is equal to the optical power after the temperature change, thereby ensuring that the high-power microwave detector is in a stable linear working area.

[0010] Further, the bias compensation device includes a temperature sensing system and a bias control system;

[0011] The temperature sensing system is used to obtain external temperature data and transmit it to the bias control system;

[0012] The bias control system is used to adjust the bias voltage input to the bias electrode according to the external temperature data and a compensation strategy.

[0013] Furthermore, the compensation strategy includes:

[0014] The bias voltage on the bias electrode should satisfy:

[0015]

[0016] Where q is the phase difference caused by the bias voltage introduced by the bias control system, and n e is the refractive index, R 33 is the electro-optic coefficient, V is the bias voltage of the bias control system, F is the overlap factor, L is the modulation length of the bias electrode, G is the electrode spacing of the bias electrode; p is the wavelength, K is the thermo-optic coefficient, T is the external temperature change, W is the manufacturing error length, and A is the thermal expansion coefficient;

[0017] The addition of formula (7) and formula (8) should satisfy:

[0018] q+n=2xπx=1, 2,....(1-3)

[0019] According to the principle of electro-optic modulation, we can always find two phases with equal power within the cycle of two half-wave voltages, so we get:

[0020] q+n=2π(1-4)

[0021] The upper limit of the bias voltage and the corresponding relationship between the bias voltage and the temperature are determined by (1-1) to (1-4), and the bias control system adjusts the bias voltage input to the bias electrode based on the above formula.

[0022] Furthermore, the high-power microwave detection system also includes a photoelectric conversion system, which is connected to the bias compensation device through a third optical fiber; the photoelectric conversion system is used to convert the optical signal transmitted by the bias compensation device into an electrical signal to complete the detection of high-power microwaves.

[0023] Furthermore, the second optical fiber is a polarization-maintaining optical fiber.

[0024] Furthermore, the third optical fiber is a single-mode optical fiber.

[0025] Furthermore, the temperature sensing system is a temperature sensor.

[0026] Beneficial effects: The present invention realizes optical fiber isolation by setting up a separate bias compensation device, and connecting the bias compensation device to the high-power microwave detector through a second optical fiber, thereby eliminating the interference of the bias voltage on the measurement of high-power microwaves. At the same time, the bias control device adjusts the bias voltage according to the external temperature data, which solves the problem of the influence of temperature on the drift of the working point of the high-power microwave detector. It can ensure that the high-power microwave detector maintains stable linear operation under different temperature environments, which is beneficial to reduce the waveform distortion caused by temperature drift, thereby improving the measurement accuracy. At the same time, the device has a simple structure and low cost, and is suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 It is a structural schematic diagram of the high power microwave detection system of the present invention;

[0029] Figure 2 This is a diagram showing the internal structure of an X-cut Y-transmission type high-power microwave detector according to an embodiment of the present invention;

[0030] Figure 3 It is an internal structure diagram of an X-cut Y-transfer type bias control system in an embodiment of the present invention;

[0031] Figure 4 It is a cross-sectional view at the dotted lines A1-A2 and B1-B2 in the X-cut Y-transmission type high-power microwave detector and the X-cut Y-transmission type bias control system in an embodiment of the present invention;

[0032] Figure 5 for Figure 4 The relationship between the external temperature and the internal steady-state temperature in the figure;

[0033] Figure 6 for Figure 4 Schematic diagram of the pyroelectric effect in;

[0034] Figure 7 Schematic diagram of the effect of temperature on the working point drift of the X-cut Y-transmission type high-power microwave detector and the X-cut Y-transmission type bias control system in an embodiment of the present invention;

[0035] Figure 8 Graph showing the half-wave voltage of the bias electrode in an embodiment of the present invention.

[0036] In the figure: 01, laser source; 02, high power microwave detector; 021, substrate; 022, Y waveguide; 023, first straight waveguide; 024, second straight waveguide; 025, detector electrode; 03, bias compensation device; 03-1, bias control system; 031, second substrate; 032, third straight waveguide; 033, fourth straight waveguide; 034, bias electrode; 035, coupled waveguide; 03-2, temperature sensing system; 04, photoelectric conversion system; 12, first optical fiber; 23, second optical fiber; 34, third optical fiber. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0038] This embodiment provides a bias compensation device for a high power microwave detection system, such as Figure 1 As shown, the high-power microwave detection system includes a 1550nm laser source 01, an X-cut Y-transmission type high-power microwave detector 02, a bias compensation device 03, a photoelectric conversion system 04, a first optical fiber 12, a second optical fiber 23 and a third optical fiber 34;

[0039] Among them, the laser source 01 is connected to one end of the X-cut Y-transmission type high-power microwave detector 02 through the first optical fiber 12, the other end of the X-cut Y-transmission type high-power microwave detector 02 is connected to one end of the bias compensation device 03 through the second optical fiber 23, and the other end of the bias compensation device 03 is connected to the photoelectric conversion system 04 through the third optical fiber 34.

[0040] Specifically, the first optical fiber 12 and the second optical fiber 23 are both polarization-maintaining optical fibers; and the third optical fiber 34 is a single-mode optical fiber.

[0041] Specifically, the working process of the high-power microwave detection system is as follows: the light source emitted by the laser source 01 is transmitted to the high-power microwave detector 02 via the first optical fiber 12. When high-power microwaves exist in the space, the light transmitted in the high-power microwave detector 02 will have a phase difference, which is transmitted to the bias compensation device 03 via the second optical fiber 23. The bias compensation device 03 converts the light phase difference into a change in light intensity. The light output by the bias compensation device 03 is transmitted to the photoelectric conversion system 04 via the third optical fiber 34. The photoelectric conversion system 04 converts the optical signal into an electrical signal to complete the detection of high-power microwaves.

[0042] Specifically, existing literature points out that temperature is the main reason for the operating point drift of materials with electro-optical modulation effect such as lithium niobate, and Figure 5 As shown, when the external temperature changes, the steady-state temperature inside the X-cut Y-transmission type high-power microwave detector 02 and the X-cut Y-transmission type bias control system 03-1 will eventually be consistent with the external temperature. Therefore, it is only necessary to establish the relationship between the external temperature and the detector working point offset, so as to adjust the detector working point in real time according to the change of the external temperature.

[0043] Furthermore, considering the manufacturing error, when the external temperature changes, the X-cut Y-transmission type high-power microwave detector 02 and the X-cut Y-transmission type bias control system 03-1 will produce thermo-optical effect and thermal expansion effect, resulting in a change in the phase difference between the first straight waveguide 023 and the second straight waveguide 024, and a change in the phase difference between the third straight waveguide 032 and the fourth straight waveguide 033, which will cause the working point to drift; at the same time, changes in the external temperature will also cause the X-cut Y-transmission type high-power microwave detector 02 and the X-cut Y-transmission type bias control system 03-1 to produce pyroelectric effect, specifically, as Figure 6 As shown, the phase difference between the first straight waveguide 023 and the second straight waveguide 024 changes, and the phase difference between the third straight waveguide 032 and the fourth straight waveguide 033 changes, thereby causing the working point to drift.

[0044] From the above, it can be seen that in a high-power microwave scenario, the electro-optical properties of materials such as lithium niobate will be affected by temperature (thermal light, thermal expansion and pyroelectricity), causing the detector working point to drift. Therefore, in this embodiment, a bias compensation device 03 is set between the high-power microwave detector 02 and the photoelectric conversion system 04. The bias compensation device adjusts the bias voltage according to the external temperature data and the compensation strategy, so that the optical power before the temperature change is equal to the optical power after the temperature change, thereby ensuring that the high-power microwave detector is in a stable linear working area.

[0045] In a specific embodiment, the bias compensation device 03 includes a temperature sensing system 03-1 and an X-cut Y-transfer type bias control system 03-2;

[0046] Specifically, the temperature sensing system is used to obtain external temperature data and transmit it to the bias control system;

[0047] Specifically, the bias control system is used to adjust the bias voltage input to the bias electrode according to the external temperature data and the compensation strategy.

[0048] Specifically, when the temperature sensing system detects that the external temperature is room temperature, the bias control system 03-1 controls the bias voltage on the bias electrode 034 to be zero; when the temperature sensing system detects that the external temperature has changed, the bias control system 03-1 adjusts the bias voltage input to the bias electrode 034 according to the external temperature data, so that the optical power is always equal to the optical power before the temperature changes, thereby ensuring that the high-power microwave detector is in a stable linear working area.

[0049] In a specific embodiment, the temperature sensing system is a temperature sensor.

[0050] Specifically, in this embodiment, Figure 2 As shown, the X-cut Y-transmission type high-power microwave detector 02 is composed of a first substrate 021, a Y waveguide 022, a first straight waveguide 023, a second straight waveguide 024, a high-power microwave sensing antenna and an electrode 025; Figure 3 As shown, the X-cut Y-transmission type bias control system 03 - 1 is composed of a second substrate 031 , a third straight waveguide 032 , a fourth straight waveguide 033 , a bias electrode 034 and a 3dB coupling waveguide 035 .

[0051] Specifically, the first substrate 021 and the second substrate 031 are both lithium niobate substrates.

[0052] The process of reducing the working point drift of the high power microwave detector by the bias compensation device 03 is as follows:

[0053] The light source emitted by the laser source 01 is transmitted to the high-power microwave detector 02 through the first polarization-maintaining optical fiber 12, and then is divided into two beams of light with equal intensity and the same phase through the Y waveguide 022, and then enters the straight waveguide 023 and the straight waveguide 024 for transmission respectively. Since materials such as lithium niobate have an electro-optical modulation effect, when there are high-power microwaves in the space, the high-power microwave sensing antenna and the detector electrode 025 will generate an induced voltage, resulting in the light phases transmitted in the first straight waveguide 023 and the second straight waveguide 024 are no longer equal. The two beams of light are transmitted to the bias control system 03-1 in the bias compensation device 03 through two polarization-maintaining optical fibers 23, and are transmitted in the third straight waveguide 032 and the fourth straight waveguide 033. The 3dB coupler 035 is used to convert the optical phase difference into a change in optical intensity. At this time, the two beams of light are differential signals, and are transmitted to the photoelectric conversion system 04 through two single-mode optical fibers 34. In this process, Figure 7 As shown, when the optical waveguide is perfectly symmetrical, the relationship between the high-power microwave and the optical power should be at point O1. Considering the manufacturing error, it is assumed that the relationship between the high-power microwave and the optical power is at point O2.

[0054] Assuming that the relationship between the high-power microwave and the optical power drifts and is at point O3 when the external temperature rises, the bias control system 03-1 will adjust the bias voltage input to the bias electrode 034 in real time according to the detected temperature change, so that the relationship between the high-power microwave and the optical power is at point O4;

[0055] Assuming that the relationship between the high-power microwave and the optical power drifts and is at point O5 when the external temperature rises, the bias control system 03-1 will adjust the bias voltage input to the bias electrode 034 in real time according to the detected temperature change, so that the relationship between the high-power microwave and the optical power is at point O6;

[0056] Therefore, from Figure 7 It can be seen that no matter how the external temperature changes, the bias control system 03-1 only needs to adjust the half-wave voltage for two cycles at most to ensure that the relationship between the high-power microwave and the optical power is always at the point equal to O2.

[0057] Specifically, in this embodiment, the Y-waveguide 022 needs to meet the low loss requirement.

[0058] Specifically, in this embodiment, preferably, two groups of high-power microwave induction antennas and electrodes are respectively provided.

[0059] Specifically, in this embodiment, the 3dB coupling waveguide 035 needs to meet the requirements of low loss and 3dB proportional output.

[0060] Specifically, in this embodiment, by setting the bias electrode 034 to a push-pull structure, such as Figure 8As shown, a half-wave voltage of 6V is obtained. At this time, the bias control system 03-1 is guaranteed to adjust the bias voltage input to the bias electrode 034 in real time according to the change of temperature so that it does not exceed 12V. Then, no matter how the external temperature changes, the relationship between the high-power microwave and the optical power is always at a point equal to O2.

[0061] Specifically, the photoelectric conversion system 04 is composed of a photoelectric balance detection circuit. The differential signal transmitted in the two single-mode optical fibers 34 will further reduce noise and improve detection sensitivity after passing through the photoelectric balance detection circuit.

[0062] Specifically, in the high-power microwave detector 02, the light transmitted in the first straight waveguide 023 and the second straight waveguide 024 are respectively expressed as:

[0063]

[0064] Among them, E 0 is the laser source amplitude, E 1 is the amplitude of the light in the second straight waveguide 024, E 2 is the amplitude of light in the first straight waveguide 023, and m is the phase difference caused by high-power microwaves;

[0065] After passing through the bias control system 03-1 in the bias compensation device 03, the two beams of light are differential signals, and the optical power can be expressed as:

[0066]

[0067] Among them, I 0 is the laser source power, I 1 ,I 2 are the two differential signal optical powers in the single-mode optical fiber 34;

[0068] From (1) to (4), it can be seen that when the optical waveguides of the high-power microwave detector 02 and the bias control system 03-1 are perfectly symmetrical, the working point drift of the detector is independent of temperature. Considering the manufacturing error, the actual light intensity in the single-mode optical fiber 34 should be:

[0069]

[0070] Where n is the phase difference caused by temperature when considering manufacturing errors and satisfies:

[0071]

[0072] Where p is the wavelength, K is the thermo-optic coefficient, T is the change in ambient temperature, W is the manufacturing error length, and A is the thermal expansion coefficient;

[0073] In order to eliminate the influence of n, the introduced bias voltage should satisfy:

[0074]

[0075] Where, q is the phase difference caused by the bias voltage introduced by the bias control system 03-1, and n e is the refractive index, R 33 is the electro-optic coefficient, V is the bias voltage of the bias control system 03-1, F is the overlap factor, L is the modulation length of the bias electrode 034, and G is the electrode spacing of the bias electrode 034;

[0076] The addition of formula (7) and formula (8) should satisfy:

[0077] q+n=2xπx=1,2,....(9)

[0078] According to the above formula, it can be inferred that x is affected by n, and the sum of q and n always changes with a period of 2π. Therefore, it is only necessary to find the corresponding relationship between temperature and bias voltage in one interval. The relationship between temperature and bias voltage in the remaining intervals corresponds to the relationship in this interval. According to the principle of electro-optic modulation, it is known that two phases with equal power can always be found within the period of two half-wave voltages, so we get:

[0079] q+n=2π(10)

[0080] Furthermore, the upper limit of the bias voltage and the corresponding relationship between the bias voltage and the temperature are determined by (7) to (10), and the bias control system adjusts the bias voltage input to the bias electrode based on the above formula.

[0081] Specifically, Figure 4 As shown, the manufacturing technology of the waveguide in this embodiment adopts the proton exchange process. In practice, other manufacturing technologies such as titanium diffusion, thin film, etc. can also be used, and the size of the waveguide in this embodiment should meet the single-mode transmission requirements.

[0082] Specifically, the method proposed in this embodiment can effectively compensate for any high-power microwave detector made of materials with working point drift characteristics (such as silicon, lithium tantalate, etc.).

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bias compensation device for a high-power microwave detection system, wherein the high-power microwave detection system comprises a high-power microwave detector, characterized in that: The bias compensation device is connected to the high-power microwave detector via a second optical fiber; The high-power microwave detector transmits the light emitted by the light source to the bias compensation device through the second optical fiber; The bias compensation device adjusts the bias voltage according to the external temperature data and the compensation strategy, so that the optical power before the temperature change is equal to the optical power after the temperature change, thereby ensuring that the high-power microwave detector is in a stable linear working area.

2. The bias compensation device for a high power microwave detection system according to claim 1, characterized in that: The bias compensation device includes a temperature sensing system and a bias control system; The temperature sensing system is used to obtain external temperature data and transmit it to the bias control system; The bias control system is used to adjust the bias voltage input to the bias electrode according to the external temperature data and a compensation strategy.

3. The bias compensation device for a high power microwave detection system according to claim 2, characterized in that: The compensation strategies include: The bias voltage on the bias electrode should satisfy: Where q is the phase difference caused by the bias voltage introduced by the bias control system, and n e is the refractive index, R 33 is the electro-optic coefficient, V is the bias voltage of the bias control system, F is the overlap factor, L is the modulation length of the bias electrode, G is the electrode spacing of the bias electrode; p is the wavelength, K is the thermo-optic coefficient, T is the external temperature change, W is the manufacturing error length, and A is the thermal expansion coefficient; The addition of formula (7) and formula (8) should satisfy: q+n=2xπx=1, 2,....(1-3) According to the principle of electro-optic modulation, we can always find two phases with equal power within the cycle of two half-wave voltages, so we get: q+n=2π(1-4) The upper limit of the bias voltage and the corresponding relationship between the bias voltage and the temperature are determined by (1-1) to (1-4), and the bias control system adjusts the bias voltage input to the bias electrode based on the above formula.

4. The bias compensation device for a high power microwave detection system according to claim 3, characterized in that: The high-power microwave detection system further comprises a photoelectric conversion system, and the photoelectric conversion system is connected to the bias compensation device via a third optical fiber; The photoelectric conversion system is used to convert the optical signal transmitted by the bias compensation device into an electrical signal to complete the detection of high-power microwaves.

5. The bias compensation device for a high power microwave detection system according to claim 1, characterized in that: The second optical fiber is a polarization-maintaining optical fiber.

6. The bias compensation device for a high power microwave detection system according to claim 4, characterized in that: The third optical fiber is a single-mode optical fiber.

7. The bias compensation device for a high power microwave detection system according to claim 2, characterized in that: The temperature sensing system is a temperature sensor.

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