Automatic testing system and method for a four-quadrant apd assembly

Abstract

This invention belongs to the field of photodetector technology, specifically disclosing an automatic testing system and method for a four-quadrant APD component. The system includes: a temperature-controlled chamber providing a controllable temperature testing environment; an optical unit generating a stable test beam with adjustable intensity; a fixing fixture installed inside the temperature-controlled chamber, where the device under test (DUT) is installed during testing, and the fixture can be adjusted to switch between different quadrants, allowing the light source to switch between different photosensitive surfaces of the DUT; and a measurement and control unit including a bias power supply, an oscilloscope, a picoammeter, a temperature control and acquisition module, and a host computer. This system, by integrating a temperature control unit, a precision mechanical alignment structure, multi-parameter measurement hardware, and host computer control software, achieves automated, high-precision, multi-parameter testing of APD four-quadrant components across the entire temperature range, significantly improving testing efficiency and reliability.

Description

Technical Field

[0001] This invention belongs to the field of photodetector technology, and in particular relates to an automatic testing system and method for a four-quadrant APD component. Background Technology

[0002] Four-quadrant APD components are high-sensitivity, high-response photodetectors widely used in laser guidance, photoelectric tracking, and free-space optical communication. Their performance parameters, such as dark noise, responsivity, and quadrant crosstalk, change significantly with ambient temperature. Therefore, comprehensive performance testing must be conducted within their operating temperature range during product development, production, and quality control.

[0003] Currently, the testing of APD four-quadrant components often has the following problems: 1. Poor temperature adaptability: Most testing systems operate at room temperature and cannot achieve automated testing in high and low temperature environments (such as -40°C to +85°C). Manual transfer of devices between different temperature chambers and testing fixtures is required, which is inefficient and prone to introducing human error and damage risks.

[0004] 2. Low level of automation: The testing process relies on manual operation and recording. The test parameters are limited and cannot achieve continuous and automatic acquisition and analysis of multiple parameters (such as dark noise, gain, responsivity, etc.), resulting in poor consistency of test results.

[0005] 3. Insufficient alignment accuracy and stability: Traditional optical path alignment methods (such as manual adjustment) have poor repeatability. During temperature cycling, the optical path is prone to shift due to thermal expansion and contraction, resulting in unreliable test results. In actual operation, manual alignment is also very unstable.

[0006] 4. Low testing efficiency: Due to the lack of system integration, the testing of each parameter requires reconfiguration of the instrument, and the entire testing cycle is long, which cannot meet the needs of mass production.

[0007] Therefore, there is an urgent need for an APD four-quadrant component testing solution that can achieve full temperature range, multiple parameters, high precision, and automation. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide an automatic testing system and method for four-quadrant APD components. The system integrates a temperature control unit, a precision mechanical alignment structure, multi-parameter measurement hardware and host computer control software to achieve automated, high-precision, multi-parameter testing of APD four-quadrant components across the entire temperature range, significantly improving testing efficiency and reliability.

[0009] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an automated testing system for a four-quadrant APD component, comprising: A temperature control chamber, which provides a controllable temperature testing environment; An optical unit for generating a stable test beam with adjustable intensity; A fixing fixture is installed inside a temperature control chamber. During testing, the test piece is installed inside the fixing fixture, and the fixing fixture can be adjusted to switch between different quadrants, thereby enabling the light source to switch between different photosensitive surfaces of the test piece. Measurement and control unit, the measurement and control unit comprising: A bias power supply, which provides the required bias voltage to the device under test; An oscilloscope used for time-division measurement of voltage output waveforms in different quadrants; Pimoammeter, the picoammeter being used for time-division measurement of output current in different quadrants; A temperature control and acquisition module, which communicates with the temperature control box, is used to set the target temperature and measure the actual temperature inside the temperature control box in real time. The host computer is used to set parameters, collect and process data, and generate test reports.

[0010] Furthermore, it also includes a multi-channel switch control module, which is used to automatically switch the bias voltage.

[0011] Furthermore, the optical unit includes a function signal generator, a DFB light source, an optical fiber patch cord, and an FC flange. The function signal generator is used to drive the DFB light source to generate a stable test beam with adjustable intensity. The optical fiber patch cord extends into the fixing fixture and is connected to the fixing fixture through the FC flange.

[0012] Furthermore, the fixing fixture includes a test base and a test cover. The test piece is installed in the central cavity of the test base, and the test cover is installed on the test base. The test cover is provided with an outer rotating ring and an inner rotating ring, and the outer rotating ring and the inner rotating ring are provided with rotating handles. A mounting base is provided inside the test cover. During testing, the fiber optic patch cord extends into the mounting base and is fixed to the mounting base by the FC flange. When the outer rotating ring rotates, it pushes the mounting base down to press the test piece tightly. The inner rotating ring is provided with an eccentric hole. When the inner rotating ring rotates, it drives the fiber optic patch cord to rotate eccentrically to complete quadrant switching.

[0013] Furthermore, clamping blocks are provided on both sides of the test cover. The clamping blocks are rotatably mounted on the test cover via a rotating shaft, and a torsion spring is provided on the rotating shaft. When the clamping blocks on both sides are pressed by hand, the clamping blocks on both sides open and the test cover is removed. After the test piece is installed, the test cover and the test base are aligned. Then, the clamping blocks on both sides are pressed by hand, and then the clamping blocks are released. Under the action of the torsion spring, the clamping blocks on both sides are engaged with the test base on their lower side.

[0014] An automated testing method for a four-quadrant APD component includes the following steps: S1: Alignment and switching of the light source and APD component in each quadrant are completed by adjusting the fixing fixture; S2: Set the temperature point and bias voltage in the host computer; S3: Controls the temperature of the temperature control box and automatically measures various parameters at each stable temperature point.

[0015] The parameter measurements include dark noise parameter measurement, responsivity parameter measurement, and maximum output voltage measurement.

[0016] The parameter measurements also include breakdown voltage measurement, responsivity measurement, and temperature-sensitive voltage measurement.

[0017] A control method for automatic testing of four-quadrant APD components includes: Test sequence configuration module: used to receive user-defined temperature sequence, voltage sequence, and light source parameters; Instrument drive and control module: used to coordinate and control the temperature control box, bias power supply, switch matrix, picoammeter, and light source; Data acquisition and processing module: used to synchronously acquire current, voltage, and temperature data, and automatically calculate derived parameters; Data visualization and report generation module: used to display test curves in real time and generate test reports in standard format.

[0018] Compared with the prior art, the present invention has the following significant advantages: 1. Achieved true full-temperature automated testing: Through system integration and software control, high and low temperature environment generation, multi-parameter electrical measurement, and optical excitation are integrated into one, realizing fully automated testing from low temperature to high temperature, which greatly improves testing efficiency and consistency.

[0019] 2. Ensured the accuracy and reliability of the test: The use of precision mechanical alignment and fixing units, through a rigid structure, overcame the problem of optical path drift caused by temperature cycling, ensuring the stability of the spot position throughout the test, thereby obtaining highly repeatable test data.

[0020] 3. Comprehensive testing functions: It can automatically complete the measurement and calculation of multiple key parameters such as dark noise, responsivity, and breakdown voltage in one go, providing a comprehensive four-quadrant APD component performance characterization.

[0021] 4. Improved production and R&D efficiency: This system and method are particularly suitable for mass production inspection and characteristic analysis in the R&D stage of APD four-quadrant modules. It can quickly and accurately obtain the temperature characteristics of the modules, shorten the product development cycle, and reduce production costs.

[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a hardware connection diagram of the automatic testing system of the present invention. Figure 2 This is a schematic diagram showing the connection of the optical elements of the present invention; Figure 3 This is a top view of the fixing clamp of the present invention; Figure 4 This is a cross-sectional view of the fixing clamp of the present invention; Figure 5 This is a flowchart illustrating the operation of the automatic testing system of the present invention. Detailed Implementation

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual photographs, and should not be construed as limiting this patent. To better illustrate the embodiments of the invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0026] like Figure 1-4 As shown, an automated testing system for a four-quadrant APD component includes: Temperature control chamber 1, which is used to provide a controllable temperature testing environment; Optical unit 2, which is used to generate a stable test beam with adjustable intensity; Fixture 3 is installed inside temperature control chamber 1. During testing, the test piece is installed inside fixture 3, and the switching between different quadrants can be achieved by adjusting fixture 3, thereby enabling the switching of light source to different photosensitive surfaces of the test piece. Measurement and control unit, the measurement and control unit comprising: Bias power supply 4, which is used to provide the required bias voltage to the device under test; Oscilloscope 5, which is used for time-division measurement of voltage output waveforms in different quadrants; Pimoammeter 6, the picoammeter 6 being used for time-division measurement of output current in different quadrants; Temperature control and acquisition module 7, which communicates with temperature control box 1, is used to set the target temperature and measure the actual temperature inside the temperature control box in real time; The host computer 8 is used to set parameters, collect and process data, and generate test reports.

[0027] In this embodiment, a multi-channel switch control module 9 is also included, which is used to automatically switch the bias voltage.

[0028] In this embodiment, the optical unit 2 includes a function signal generator 21, a DFB light source 22, an optical fiber patch cord 23, and an FC flange 24. The function signal generator 21 is used to drive the DFB light source 22 to generate a stable test beam with adjustable intensity. The optical fiber patch cord 23 extends into the fixing fixture 3 and is connected to the fixing fixture 3 through the FC flange 24.

[0029] In this embodiment, the fixing fixture 3 includes a test base 31 and a test cover 32. The test piece 10 is installed in the central cavity of the test base 31. The test cover 32 is installed on the test base 31 and is provided with an outer rotating ring 33 and an inner rotating ring 34. The outer rotating ring 33 and the inner rotating ring 34 are provided with rotating handles. A mounting base 35 is provided inside the test cover 32. During testing, the fiber optic patch cord 23 extends into the mounting base 35 and is fixed to the mounting base 35 by the FC flange 24. When the outer rotating ring 33 rotates, it pushes the mounting base 35 down to press the test piece 10 tightly. The inner rotating ring 34 is provided with an eccentric hole. When the inner rotating ring 34 rotates, it drives the fiber optic patch cord 23 to rotate eccentrically to complete quadrant switching.

[0030] In this embodiment, clamping blocks 36 are provided on both sides of the test cover 32. The clamping blocks 36 are rotatably mounted on the test cover 32 via a rotating shaft, and a torsion spring is provided on the rotating shaft. When the clamping blocks 36 on both sides are pressed by hand, the clamping blocks 36 on both sides open and the test cover 32 is removed. After the test piece 10 is installed, the test cover 32 and the test base 31 are aligned. The clamping blocks 36 on both sides are pressed by hand, and then the clamping blocks 36 are released. Under the action of the torsion spring, the lower side of the clamping blocks 36 on both sides is fastened to the test base 31.

[0031] An automated testing method for a four-quadrant APD component includes the following steps: S1: Alignment and switching of the light source and APD component in each quadrant are completed by adjusting the fixing fixture; S2: Set the temperature point and bias voltage in the host computer; S3: Controls the temperature of the temperature control box and automatically measures various parameters at each stable temperature point.

[0032] The parameter measurements include dark noise parameter measurement, responsivity parameter measurement, and maximum output voltage measurement.

[0033] The parameter measurements also include breakdown voltage measurement, responsivity measurement, and temperature-sensitive voltage measurement.

[0034] like Figure 5 As shown, the specific operation process is as follows: First, the host computer controls the temperature control box to start changing the temperature. When the temperature reaches and stabilizes at the target temperature (selected temperature), the system automatically executes the following sub-steps: a. Temperature test of the test piece: Turn on the light source, switch quadrants using a switch matrix, and measure the temperature value of the test piece at this time.

[0035] b. Test device bias voltage test: Turn on the light source, switch quadrants through the switch matrix, and measure the bias voltage value of the test device after it is working normally.

[0036] c. Responsivity test: Turn on the light source, switch quadrants using a switch matrix, use an oscilloscope to measure the output amplitude of the device under test, and calculate the responsivity value of the device under test.

[0037] d. Response consistency test: Turn on the light source, switch quadrants using a switch matrix, and use an oscilloscope to calculate the consistency of the output in the four quadrants.

[0038] e. Amplitude test before one decay: Turn on the light source, switch quadrants using a switch matrix, and use an oscilloscope to test the amplitude value before one decay output by the device under test.

[0039] f. Amplitude test after one decay: Turn on the light source, switch quadrants through the switch matrix to enable one decay control, and use an oscilloscope to test the amplitude value after one decay output of the device under test.

[0040] g. One-time decay test: The one-time decay value can be obtained by calculating the amplitude ratio before and after the first decay.

[0041] h. One-decay attenuation inconsistency test: The one-decay attenuation inconsistency value can be obtained by comparing the amplitude ratio before and after one decay in the four quadrants.

[0042] i. Amplitude test before two-fade: Turn on the light source, switch quadrants using a switch matrix, and use an oscilloscope to test the amplitude value before two-fade output of the device under test.

[0043] j. Amplitude test after two-fade: Turn on the light source, switch quadrants through the switch matrix to enable two-fade control, and use an oscilloscope to test the amplitude value after two-fade output of the device under test.

[0044] k. Two-way decay test: The two-way decay value can be obtained by calculating the amplitude ratio before and after the two-way decay.

[0045] l. Two-way decay inconsistency test: The two-way decay inconsistency value can be obtained by comparing the amplitude ratio before and after two-way decay in the four quadrants.

[0046] m. Maximum output voltage test: Turn on the light source, switch quadrants using the switch matrix, increase the optical signal power until the output signal waveform is saturated, and read the amplitude on the oscilloscope at this time, which is the maximum output voltage value of the device under test.

[0047] n. Dark noise test: The light source is switched on and off, and the quadrants are switched using a switching matrix. An oscilloscope is used to read the waveform amplitude value at this time, which is recorded as the dark noise value of the device under test.

[0048] o. Breakdown voltage test: With the light source off and on, increase the breakdown voltage until the bias voltage and current of the device under test are 2 microamps. The bias voltage value at this time is recorded as the breakdown voltage value of the device under test.

[0049] After completing all tests at the current temperature point, manually lift the glass cover, switch the test quadrant, and repeat the above sub-steps until all four quadrant tests are completed. This completes the testing of all parameters at that temperature. Manually set the host computer to control the temperature control chamber to change to the next target temperature point, and repeat the above sub-steps until all parameters at all set temperature points are tested. Click the "Generate Filtered Test Report" button to generate the test report.

[0050] A control method for automatic testing of four-quadrant APD components includes: Test sequence configuration module: used to receive user-defined temperature sequence, voltage sequence, and light source parameters; Instrument drive and control module: used to coordinate and control the temperature control box, bias power supply, switch matrix, picoammeter, and light source; Data acquisition and processing module: used to synchronously acquire current, voltage, and temperature data, and automatically calculate derived parameters; Data visualization and report generation module: used to display test curves in real time and generate test reports in standard format.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An automatic testing system for a four-quadrant APD assembly, characterized by, include: A temperature control chamber, which provides a controllable temperature testing environment; An optical unit for generating a stable test beam with adjustable intensity; A fixing fixture is installed inside a temperature control chamber. During testing, the test piece is installed inside the fixing fixture, and the fixing fixture can be adjusted to switch between different quadrants, thereby enabling the light source to switch between different photosensitive surfaces of the test piece. Measurement and control unit, the measurement and control unit comprising: A bias power supply, which provides the required bias voltage to the device under test; An oscilloscope used for time-division measurement of voltage output waveforms in different quadrants; Pimoammeter, the picoammeter being used for time-division measurement of output current in different quadrants; A temperature control and acquisition module, which communicates with the temperature control box, is used to set the target temperature and measure the actual temperature inside the temperature control box in real time. The host computer is used to set parameters, collect and process data, and generate test reports.

2. The automatic test system of a four-quadrant APD assembly of claim 1, wherein, It also includes a multi-channel switch control module, which is used to automatically switch the bias voltage.

3. The automatic test system of four-quadrant APD assemblies of claim 1, wherein, The optical unit includes a function signal generator, a DFB light source, an optical fiber patch cord, and an FC flange. The function signal generator is used to drive the DFB light source to generate a stable test beam with adjustable intensity. The optical fiber patch cord extends into the fixing fixture and is connected to the fixing fixture through the FC flange.

4. The automatic test system of four-quadrant APD assemblies of claim 1, wherein, The fixing fixture includes a test base and a test cover. The test piece is installed in the central cavity of the test base. The test cover is installed on the test base and has an outer rotating ring and an inner rotating ring. The outer rotating ring and the inner rotating ring are equipped with rotating handles. A mounting base is provided inside the test cover. During testing, the fiber optic patch cord extends into the mounting base and is fixed to the mounting base by an FC flange. When the outer rotating ring rotates, it pushes the mounting base down to press the test piece tightly. The inner rotating ring is provided with an eccentric hole. When the inner rotating ring rotates, it drives the fiber optic patch cord to rotate eccentrically to complete quadrant switching.

5. The automatic test system of four-quadrant APD assemblies of claim 1, wherein, Clamping blocks are provided on both sides of the test cover. The clamping blocks are rotatably mounted on the test cover via a rotating shaft, and a torsion spring is provided on the rotating shaft. When the clamping blocks on both sides are pressed by hand, the clamping blocks on both sides open and the test cover is removed. After the test piece is installed, the test cover and the test base are aligned. Then, the clamping blocks on both sides are pressed by hand and then released. Under the action of the torsion spring, the clamping blocks on both sides are snapped onto the test base from the bottom.

6. A method of automatically testing a four-quadrant APD assembly, the method comprising: Includes the following steps: S1: Alignment and switching of the light source and APD component in each quadrant are completed by adjusting the fixing fixture; S2: Set the temperature point and bias voltage in the host computer; S3: Controls the temperature of the temperature control box and automatically measures various parameters at each stable temperature point.

7. The method of claim 6, wherein, The parameter measurements include dark noise parameter measurement, responsivity parameter measurement, and maximum output voltage measurement.

8. The method of claim 6, wherein, The parameter measurements also include breakdown voltage measurement, responsivity measurement, and temperature-sensitive voltage measurement.

9. A control method for automatic testing of a four-quadrant APD assembly, characterized by, include: Test sequence configuration module: used to receive user-defined temperature sequence, voltage sequence, and light source parameters; Instrument drive and control module: used to coordinate and control the temperature control box, bias power supply, switch matrix, picoammeter, and light source; Data acquisition and processing module: used to synchronously acquire current, voltage, and temperature data, and automatically calculate derived parameters; Data visualization and report generation module: used to display test curves in real time and generate test reports in standard format.

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