Two-channel structure photoconductive switch for improving radio frequency conversion efficiency

Abstract

The invention discloses a double-channel structure photoconductive switch for improving radio frequency conversion efficiency, which comprises two mutually symmetrical electrodes as direct current input ends, positive voltage and negative voltage which are equal in numerical value are respectively added to the two electrodes, and an electrode positioned in the central area of the surface of a device is used as a device output end. A traditional photoconductive switch is of a single-channel structure, the input voltage is constantly positive voltage or negative voltage, in a linear working mode, the output current is constantly larger than zero or constantly smaller than zero, more direct current signals are included, and the radio frequency conversion efficiency is low. According to the characteristic that a radio frequency power amplifier has high output efficiency in a push-pull circuit, the double-channel structure photoconductive switch capable of improving the radio frequency conversion efficiency is provided, optical signals with the 180-degree phase difference are input into the two light incident faces respectively, electric signals are output and synthesized under positive and negative voltages, direct-current components can be fully utilized, and the radio frequency conversion efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of optoelectronics and microwave technology, in particular to a dual-channel structure photoconductive switch for improving radio frequency conversion efficiency. Background Art

[0002] A photoconductive switch is an optoelectronic semiconductor device that can use photoelectric conversion to achieve RF output function. It usually has two working modes: linear and nonlinear. Its nonlinear mode outputs short pulses and wide spectrum signals, and the frequency cannot be accurately controlled. In its linear working mode, when an RF modulated laser signal is input, the photoconductive switch can output an electrical pulse signal consistent with the modulated light pulse frequency under a bias voltage, and can perform single-frequency modulation and broadband tuning. Compared with relativistic electric vacuum devices and solid-state RF transistor devices, the linear mode of photoconductive switches to generate microwaves has the comprehensive advantages of high power density, flexible and adjustable frequency, and easy integration.

[0003] The output signal of the linear mode of the photoconductive switch mainly includes two parts: the RF modulation main frequency and the DC component, which is similar to the output of the Class A amplification mode of the transistor amplifier. The most ideal microwave power output efficiency is only 50%. Referring to the high output efficiency of the RF power amplifier in the push-pull circuit, in the photoconductive microwave link, two output photocurrent signals with a phase difference of 180°, positive current and negative current, and equal magnitude can be superimposed to convert the DC component to the required main frequency signal to the maximum extent, reduce the loss of the DC component in the microwave link, and improve the efficiency of converting the input electrical power into the output RF power. At present, the common configurations of photoconductive switches include a single light incident surface, multiple device stacking, and multiple light incident points evenly distributed in the same surface area. Their common point is that there are only two external electrodes, and the RF conversion efficiency of the output signal is low. The two devices can be pushed-pull synthesized, but due to the influence of the packaging structure and circuit size, it is not conducive to integration, which will increase the volume and weight of the system and reduce the power density. Summary of the invention

[0004] The purpose of the present invention is to provide a dual-channel structure photoconductive switch that improves the radio frequency conversion efficiency. Two photoelectric conversion channels are integrated on the same photoconductive switch device, and the advantages of the push-pull circuit are utilized to generate two photocurrent signals of equal magnitude, a phase difference of 180°, positive and negative respectively, and synthesize and output a radio frequency signal with high conversion efficiency.

[0005] The technical solution for achieving the purpose of the present invention is: a dual-channel structure photoconductive switch for improving radio frequency conversion efficiency, comprising a photoconductive semiconductor, a first input terminal electrode, a second input terminal electrode, and an output terminal electrode, wherein the photoconductive semiconductor, the first input terminal electrode, the second input terminal electrode, and the output terminal electrode are connected by welding; wherein the first input terminal electrode and the second input terminal electrode are located on the same side of the photoconductive semiconductor, and the output terminal electrode is located in the central area of ​​the photoconductive semiconductor.

[0006] Furthermore, the photoconductive semiconductor is a rectangular parallelepiped structure, one side of which contains two light incident areas as a dual-channel light incident surface.

[0007] Furthermore, the first input end electrode and the second input end electrode have the same size and are located symmetrically with respect to two center lines of the photoconductive semiconductor.

[0008] Furthermore, the region between the output terminal electrode and the first input terminal electrode and the second input terminal electrode is the region where light is incident and photoelectric conversion occurs; and the shape of the output terminal electrode is symmetrical about the two center lines of the rectangular photoconductive semiconductor.

[0009] Furthermore, the photoconductive semiconductor is made of GaAs, GaN, SiC or Ga2O3 as a substrate.

[0010] Furthermore, the welding surfaces of the photoconductive semiconductor, the first input end electrode, the second input end electrode, and the output end electrode need to be silver-plated or gold-plated.

[0011] Furthermore, when the output end electrode and the first input end electrode and the second input end electrode are arranged on both sides of the photoconductive semiconductor, insulating silicone gel is filled between the first input end electrode and the second input end electrode to improve the withstand voltage.

[0012] Furthermore, when the output end electrode and the first input end electrode and the second input end electrode are arranged on both sides of the photoconductive semiconductor, silver is plated on the backlight surface area opposite to the light incident surface of the photoconductive semiconductor to improve the light absorption rate of the photoconductive semiconductor.

[0013] Furthermore, the backlight surface area opposite to the light incident surface of the photoconductive semiconductor is silver-plated to improve the light absorption rate of the photoconductive semiconductor.

[0014] Furthermore, the dual channels of the photoconductive semiconductor have the same photoelectric response characteristics.

[0015] Furthermore, the first input terminal electrode and the second input terminal electrode are used as DC input terminals, and positive and negative voltages of equal values ​​are applied respectively, and the output terminal electrode located in the central area of ​​the device surface is used as the device output terminal.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a single-device dual-channel integrated optical switch structure, which integrates two optoelectronic conversion channels on the same device and utilizes the advantages of the push-pull circuit to output a radio frequency signal with high conversion efficiency, thereby improving the disadvantage of a single-channel device containing more DC components. At the same time, the volume and weight of the dual-device push-pull optical microwave link are also reduced, thereby improving the integration level. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the skew-electrode photoconductive switch according to Example 1 of the present invention.

[0018] Figure 2 This is the test circuit diagram of the skew-electrode photoconductive switch of Example 1 of the present invention.

[0019] Figure 3 It is a schematic diagram of the planar electrode photoconductive switch structure of Example 2 of the present invention.

[0020] Figure 4 This is a test circuit diagram of a planar electrode photoconductive switch according to Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below with reference to the accompanying drawings. The specific embodiments described herein are only used to explain the present invention, not to limit the present invention. For example, the first input electrode 201 and the second input electrode 202 in Embodiment 1 are hollow electrodes, and the light incident area is located inside the hollow, or they can be solid electrodes, and the photosensitive area is located between the input electrode and the output electrode, provided that the photoelectric isolation of the two channels is met; the light incident surface in Embodiment 2 is the area between the three electrodes, or it can be the opposite back surface. All of these are within the protection scope of this patent.

[0022] Example 1

[0023] like Figure 1 As shown, in this embodiment, a dual-channel structure photoconductive switch for improving radio frequency conversion efficiency includes a photoconductive semiconductor 1, a first input end electrode 201, a second input end electrode 202, and an output end electrode 3, wherein the photoconductive semiconductor 1, the first input end electrode 201, the second input end electrode 202, and the output end electrode 3 are connected by welding; wherein the first input end electrode 201, the second input end electrode 202, and the output end electrode 3 are located on both sides of the photoconductive semiconductor 1, and insulating silicone gel is filled between the first input end electrode 201 and the second input end electrode 202 to improve the withstand voltage and prevent breakdown; the backlight surface area opposite to the light incident surface of the photoconductive semiconductor 3 is silver-plated to improve the light absorption rate of the photoconductive semiconductor 1.

[0024] The photoconductive semiconductor 1 is made of one of GaAs, GaN, SiC or Ga2O3 as a substrate, the welding points of the photoconductive semiconductor 1, the first input electrode 201, the second input electrode 202 and the output electrode 3 are silver-plated, and nano-silver is sintered at each connection.

[0025] like Figure 2As shown, a positive voltage is applied to the first input terminal electrode 201, and a negative voltage is applied to the second input terminal electrode 202, and the two voltages are equal in magnitude; RF modulated laser signals are input from two light incident surfaces, and the two optical signals have the same energy and frequency, and only the phase difference is 180°. The two photocurrents can be push-pull synthesized on the output terminal electrode 3 to output an RF signal with high conversion efficiency.

[0026] Example 2

[0027] like Figure 3 As shown, in this embodiment, a dual-channel structure photoconductive switch for improving radio frequency conversion efficiency includes a photoconductive semiconductor 4, a first input terminal electrode 501, a second input terminal electrode 502, and an output terminal electrode 6, wherein the photoconductive semiconductor 4, the first input terminal electrode 501, the second input terminal electrode 502, and the output terminal electrode 6 are connected by welding; wherein the first input terminal electrode 501, the second input terminal electrode 502, and the output terminal electrode 6 are located on the same side of the photoconductive semiconductor 4, and the region where the photoconductive semiconductor 1 is located between the three electrodes is a light incident and photoelectric conversion region.

[0028] The photoconductive semiconductor 4 is made of one of GaAs, GaN, SiC or Ga2O3 as a substrate, the welding points of the photoconductive semiconductor 4, the first input electrode 501, the second input electrode 502 and the output electrode 6 are silver-plated, and nano-silver sintering is used at each connection.

[0029] like Figure 4 As shown, a positive voltage is applied to the first input terminal electrode 501, and a negative voltage is applied to the second input terminal electrode 502, and the two voltages are equal in magnitude; RF modulated laser signals are input from two light incident surfaces, and the two optical signals have the same energy and frequency, and only the phase difference is 180°. The two photocurrents can be push-pull synthesized on the output terminal electrode 3 to output an RF signal with high conversion efficiency.

Claims

1. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency, characterized in that: It includes a photoconductive semiconductor, a first input terminal electrode, a second input terminal electrode and an output terminal electrode, wherein the photoconductive semiconductor, the first input terminal electrode, the second input terminal electrode and the output terminal electrode are connected by welding; wherein the first input terminal electrode and the second input terminal electrode are located on the same side of the photoconductive semiconductor, and the output terminal electrode is located in the central area of ​​the photoconductive semiconductor.

2. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The photoconductive semiconductor is a rectangular parallelepiped structure, one side of which contains two light incident areas as a dual-channel light incident surface.

3. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The first input end electrode and the second input end electrode have the same size and are located symmetrically with respect to two center lines of the photoconductive semiconductor.

4. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The area between the output electrode and the first input electrode and the second input electrode is the area where light is incident and photoelectric conversion occurs; the shape of the output electrode is symmetrical about the two center lines of the rectangular photoconductive semiconductor.

5. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The photoconductive semiconductor is made of GaAs, GaN, SiC or Ga2O3 as a substrate.

6. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The welding surfaces of the photoconductive semiconductor, the first input end electrode, the second input end electrode and the output end electrode need to be silver-plated or gold-plated.

7. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: When the output end electrode and the first input end electrode and the second input end electrode are arranged on both sides of the photoconductive semiconductor, insulating silicone gel is filled between the first input end electrode and the second input end electrode to improve the withstand voltage.

8. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: When the output end electrode and the first input end electrode and the second input end electrode are arranged on both sides of the photoconductive semiconductor, silver is plated on the backlight surface area opposite to the light incident surface of the photoconductive semiconductor to improve the light absorption rate of the photoconductive semiconductor.

9. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The double channels of the photoconductive semiconductor have the same photoelectric response characteristics.

10. A dual-channel structured photoconductive switch for improving radio frequency conversion efficiency as claimed in claim 1, characterized in that: The first input terminal electrode and the second input terminal electrode are used as direct current input terminals, and positive and negative voltages of equal value are applied to them respectively. The output terminal electrode located in the central area of ​​the device surface is used as the device output terminal.

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