Test system and method

Abstract

The application provides a test system and method, comprising a first test device and a second test device, a signal generator in the first test device outputs an adjustable high-frequency alternating current signal to a photonic integrated circuit chip, and a first modulation voltage is provided for a to-be-tested electro-optical modulator; the to-be-tested electro-optical modulator performs phase modulation on an optical signal under the action of the first modulation voltage; an oscilloscope tests an electrical signal converted based on the modulated optical signal, and determines the first modulation voltage corresponding to the to-be-tested electro-optical modulator as a half-wave voltage to determine a first source voltage; the sum of the resistance values of a resistance element, a direct current probe contact resistance and a wire resistance in the second test device is consistent with the output impedance of the signal generator; when the second source voltage determined in the second test device is consistent with the first source voltage, it is determined that the half-wave voltage based on the direct current signal test is consistent with the half-wave voltage based on the high-frequency alternating current signal test. The scheme of the application improves the test efficiency.

Description

Technical Field

[0001] This application relates to the field of modulator technology, and in particular to a testing system and method. Background Technology

[0002] Electro-optic modulators (EOMs) are modulators made using the electro-optic effect of certain electro-optic crystals, such as lithium niobate (LiNbO3), gallium arsenide (GaAs), and lithium tantalate (LiTaO3). They can convert electrical signals into optical signals and have advantages such as wide bandwidth, fast response speed, low insertion loss, and good stability. They are widely used in optical communication, fiber optic sensors, microwave photonics, and other fields.

[0003] Half-wave voltage is a crucial parameter describing the performance of electro-optic modulators. It refers to the voltage required to change the phase of an optical signal by π. In other words, when a voltage equal to the half-wave voltage is applied to the electro-optic modulator, the phase of the output optical signal will be opposite to the phase of the input optical signal. The magnitude of the half-wave voltage reflects the modulation efficiency of the electro-optic modulator; a smaller half-wave voltage indicates that a larger phase modulation can be achieved at a lower voltage, resulting in higher modulation efficiency. Therefore, accurate measurement of the half-wave voltage is of great significance for evaluating the performance of electro-optic modulators.

[0004] In traditional methods, an adjustable high-frequency electrical signal is output from a signal generator and transmitted to the electro-optic modulator under test (EDT) to provide a modulation voltage. Under this voltage, the EDT modulates the optical signal, converting it into an electrical signal. The waveform of this electrical signal is then observed using an oscilloscope and compared with a reference waveform to determine the half-wave voltage of the EDT. However, this method involves complex testing equipment and procedures, resulting in low testing efficiency. Summary of the Invention

[0005] This application provides a testing system and method to solve the problem of complex testing instruments and processes when testing the half-wave voltage of an electro-optic modulator in traditional solutions, thereby improving testing efficiency.

[0006] In a first aspect, this application provides a testing system, including a first testing device and a second testing device. The first testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, a photodetector, a signal generator, a high-frequency probe, and an oscilloscope. The photonic integrated circuit chip is provided with an electro-optic modulator under test.

[0007] The signal generator is connected to the photonic integrated circuit chip via the high-frequency probe. The signal generator outputs an adjustable high-frequency AC signal, which is transmitted to the photonic integrated circuit chip via the high-frequency probe to provide a first modulation voltage for the electro-optic modulator under test.

[0008] The optical transmitter is connected to one end of the photonic integrated circuit chip via the transmission optical fiber, and the other end of the photonic integrated circuit chip is connected to the photodetector via the transmission optical fiber. The photodetector is connected to the oscilloscope. The optical signal emitted by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. Under the action of the first modulation voltage, the electro-optic modulator under test modulates the phase of the optical signal. The modulated optical signal is transmitted to the photodetector via the transmission optical fiber, converted into an electrical signal by the photodetector, and then transmitted to the oscilloscope. The oscilloscope tests the electrical signal and determines, based on the first test result, that the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage.

[0009] When the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the first source voltage is determined;

[0010] The second testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, an optical power tester, a source measurement unit, a DC probe, and a resistive element. The photonic integrated circuit chip contains an electro-optic modulator under test.

[0011] The source measurement unit is connected to one end of the resistive element, and the other end of the resistive element is connected to the photonic integrated circuit chip through the DC probe. The source measurement unit outputs an adjustable DC signal, which is transmitted to the photonic integrated circuit chip through the resistive element and the DC probe to provide a second modulation voltage for the electro-optic modulator under test. The sum of the resistance values ​​of the resistive element, the DC probe contact resistance, and the wire resistance is consistent with the output impedance of the signal generator.

[0012] The optical transmitter is connected to one end of the photonic integrated circuit chip via the transmission optical fiber, and the other end of the photonic integrated circuit chip is connected to the optical power tester via the transmission optical fiber. The optical signal emitted by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. The electro-optic modulator under test modulates the phase of the optical signal under the action of the second modulation voltage. The modulated optical signal is transmitted to the optical power tester via the transmission optical fiber. The optical power tester tests the modulated optical signal and determines that the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage based on the second test result.

[0013] When the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the second source voltage is determined;

[0014] If the first source voltage and the second source voltage are consistent, it is determined that the half-wave voltage of the electro-optic modulator under test obtained by testing the DC signal provided by the source measurement unit is consistent with the half-wave voltage of the electro-optic modulator under test obtained by testing the high-frequency AC signal provided by the signal generator; otherwise, they are inconsistent.

[0015] Optionally, the oscilloscope is specifically used to determine that the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage when the amplitude of the waveform corresponding to the electrical signal is at its maximum.

[0016] Optionally, the optical power tester is specifically used to determine that the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage when the power of the optical signal is at its minimum.

[0017] Optionally, the optical power tester includes a power sensor for converting the high-frequency test signal of the optical signal into a low-frequency test signal and testing the power of the low-frequency test signal.

[0018] Optionally, the optical power tester also includes a display for showing the power.

[0019] Optionally, the high-level voltage of the signal generator is adjustable to output a corresponding high-frequency AC signal;

[0020] When the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the first source voltage is determined based on the high-level voltage of the signal generator.

[0021] Optionally, the voltage of the source measurement unit is adjustable to output a corresponding DC signal;

[0022] When the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the second source voltage is determined based on the voltage of the source measurement unit.

[0023] Optionally, the light emitter includes a laser, the wavelength and power of which are preset.

[0024] Optionally, the transmission optical fiber includes a polarization-maintaining fiber array.

[0025] Secondly, this application provides a testing method applied to the testing system described in the first aspect.

[0026] The testing system provided in this application includes a first testing device and a second testing device. The first testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, a photodetector, a signal generator, a high-frequency probe, and an oscilloscope. The photonic integrated circuit chip contains a modulator-to-the-light (MTD) electro-optic modulator. The signal generator can be connected to the photonic integrated circuit chip via the high-frequency probe. The signal generator outputs an adjustable high-frequency AC signal, which is transmitted to the photonic integrated circuit chip via the high-frequency probe to provide a first modulation voltage to the MTD electro-optic modulator. The optical transmitter can be connected to the photonic integrated circuit chip via the transmission optical fiber. The photonic integrated circuit chip is connected to the photodetector via the transmission optical fiber. The photodetector is connected to the oscilloscope. The electrical signal output by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. Under the action of the first modulation voltage, the MTD electro-optic modulator performs phase modulation on the optical signal. The modulated optical signal is then transmitted to the photodetector via the transmission optical fiber. After being converted into an electrical signal, the signal is transmitted to an oscilloscope. The oscilloscope tests the electrical signal and, based on the first test result, determines that the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, thus determining the first source voltage. The second testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, an optical power tester, a source measurement unit, a DC probe, and a resistive element. The photonic integrated circuit chip contains the electro-optic modulator under test. The source measurement unit can be connected to the resistive element, which is connected to the photonic integrated circuit chip via the DC probe. The source measurement unit outputs an adjustable DC signal, which is transmitted to the photonic integrated circuit chip via the resistive element and the DC probe, serving as the source voltage for the electro-optic modulator under test. The electro-optic modulator provides a second modulation voltage, wherein the sum of the resistance values ​​of the resistive element, the DC probe contact resistance, and the wire resistance is consistent with the output impedance of the signal generator. Under the action of the second modulation voltage, the electro-optic modulator under test modulates the optical signal. The modulated optical signal is transmitted to the optical power tester via the transmission fiber. The optical power tester tests the modulated optical signal. Based on the second test result, when the second modulation voltage corresponding to the electro-optic modulator under test is determined to be a half-wave voltage, the second source voltage is determined. When the first source voltage and the second source voltage are consistent, it indicates that when testing the half-wave voltage based on the DC signal provided by the source measurement unit, the resistance values ​​of the resistive element, DC probe contact resistance, and wire resistance are consistent with the output impedance of the signal generator. The voltage division of the probe contact resistance and the wire resistance is consistent with the voltage division of the output impedance of the signal generator when testing the half-wave voltage based on the high-frequency AC signal provided by the signal generator. This indicates that the voltage applied to the electro-optic modulator under test is consistent, that is, the half-wave voltages measured by the two are consistent. Therefore, the DC signal provided by the source measurement unit can be used to provide the modulation voltage for the electro-optic modulator under test and perform the half-wave voltage test, instead of using the high-frequency AC signal provided by the signal generator to provide the modulation voltage for the half-wave voltage test. This eliminates the need for complex test instruments such as signal generators and oscilloscopes, as well as complex test processes such as waveform observation, thus improving test efficiency.

[0027] These or other aspects of this application will become more apparent in the following description of the embodiments. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of one embodiment of the first testing apparatus provided in this application is shown;

[0030] Figure 2 A schematic diagram of one embodiment of a second testing apparatus provided in this application is shown. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0032] In some structures described in the specification, claims, and accompanying drawings of this application, there are multiple structural components appearing in a specific order. The serial numbers of these structural components, such as 101, 102, etc., are merely used to distinguish the different structural components. It should be noted that the descriptions such as "first" and "second" in this document are used to distinguish different structural components, and do not represent a chronological order, nor do they limit "first" and "second" to different types.

[0033] The embodiments of this application can be applied to the field of modulator technology, especially to the field of half-wave voltage testing of electro-optic modulators. In conventional solutions, a high-frequency AC signal provided by a signal generator is used to provide a modulation voltage to the electro-optic modulator under test (EDT) for half-wave voltage testing. Specifically, an adjustable high-frequency electrical signal is output from a signal generator and transmitted to the EDT to provide a modulation voltage. Under the action of the modulation voltage, the EDT modulates the phase of the optical signal and converts the modulated optical signal into an electrical signal. The waveform corresponding to the electrical signal is observed using an oscilloscope, and this waveform is compared with a reference waveform corresponding to a reference electrical signal to determine the half-wave voltage of the EDT.

[0034] However, the above-mentioned testing methods involve complex testing instruments and processes. For example, they require instruments such as signal generators and oscilloscopes. High-frequency probes are needed when transmitting high-frequency AC signals, and photodetectors are needed when converting optical signals to electrical signals. Furthermore, during the testing process, the parameters of the oscilloscope need to be adjusted to ensure that the observed waveform is clear and standard, resulting in low efficiency.

[0035] To solve the aforementioned technical problems, the inventors conceived of using DC signals for half-wave voltage testing, in addition to using high-frequency AC signals. For example, a DC signal output from a source meter can be used to provide a modulation voltage. The electro-optic modulator under test modulates the optical signal under the modulation voltage, and the half-wave voltage is determined based on the power of the modulated optical signal. Therefore, if it can be verified that the half-wave voltage measured using DC signals is consistent with the half-wave voltage measured using high-frequency AC signals, DC signals can be used to replace high-frequency AC signals for half-wave voltage testing, thereby avoiding the use of complex testing instruments and simplifying the testing process. Based on this, the inventors have proposed the technical solution of this application, providing a testing system and method, including a first testing device and a second testing device. The first testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, a photodetector, a signal generator, a high-frequency probe, and an oscilloscope. The photonic integrated circuit chip contains a modulator-to-the-light (MTB) electro-optic modulator. The signal generator is connected to the photonic integrated circuit chip via the high-frequency probe, and outputs an adjustable high-frequency AC signal, which is transmitted to the photonic integrated circuit chip via the high-frequency probe to provide a first modulation voltage to the MTB. The optical transmitter is connected to one end of the photonic integrated circuit chip via the transmission optical fiber, and the other end of the photonic integrated circuit chip is connected to the photodetector via the transmission optical fiber. The photodetector is connected to the oscilloscope. The optical signal emitted by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. Under the action of the first modulation voltage, the MTB performs phase modulation on the optical signal. The optical signal is transmitted through the transmission optical fiber to the photodetector, converted into an electrical signal by the photodetector, and then transmitted to the oscilloscope. The oscilloscope tests the electrical signal and, based on the first test result, determines that the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage. Given that the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, a first source voltage is determined. The second testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, an optical power tester, a source measurement unit, a DC probe, and a resistive element. The photonic integrated circuit chip contains the electro-optic modulator under test. The source measurement unit is connected to one end of the resistive element, and the other end of the resistive element is connected to the photonic integrated circuit chip via the DC probe. The source measurement unit outputs an adjustable DC signal, which is transmitted to the photonic integrated circuit chip via the resistive element and the DC probe to provide a second modulation voltage for the electro-optic modulator under test. The sum of the resistance values ​​of the resistive element, the DC probe contact resistance, and the wire resistance is consistent with the output impedance of the signal generator.The optical transmitter is connected to one end of the photonic integrated circuit chip via the transmission optical fiber, and the other end of the photonic integrated circuit chip is connected to the optical power tester via the transmission optical fiber. The optical signal emitted by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. The electro-optic modulator under test (EUT) modulates the phase of the optical signal under the action of the second modulation voltage. The modulated optical signal is transmitted to the optical power tester via the transmission optical fiber. The optical power tester tests the modulated optical signal and determines that the second modulation voltage corresponding to the EUT is a half-wave voltage based on the second test result. If the second modulation voltage corresponding to the EUT is a half-wave voltage, a second source voltage is determined. If the first source voltage and the second source voltage are consistent, the half-wave voltage of the EUT obtained by testing the DC signal provided by the source measurement unit is consistent with the half-wave voltage of the EUT obtained by testing the high-frequency AC signal provided by the signal generator; otherwise, they are inconsistent.

[0036] The testing system provided in this application, in a first testing device, uses a high-frequency alternating current signal to provide a first modulation voltage to the electro-optic modulator under test (EOT), and determines a first source voltage when the applied first modulation voltage is determined to be a half-wave voltage; and in a second testing device equipped with resistive elements, uses a direct current signal to provide a second modulation voltage to the EOT, and determines a second source voltage when the applied second modulation voltage is determined to be a half-wave voltage; and compares the first source voltage with the second source voltage. If the first source voltage and the second source voltage are consistent, it indicates that the half-wave voltage is being tested based on a direct current signal. The voltage division of the resistive element, the DC probe contact resistance, and the wire resistance is consistent with the voltage division of the output impedance of the signal generator when testing the half-wave voltage based on a high-frequency AC signal. This indicates that the voltage applied to the electro-optic modulator under test is consistent, meaning that the half-wave voltages measured by both methods are consistent. Therefore, a DC signal can be used to provide a modulation voltage to the electro-optic modulator under test and perform a half-wave voltage test, instead of using a high-frequency AC signal to provide the modulation voltage. This eliminates the need for complex testing instruments such as signal generators and oscilloscopes, as well as complex testing processes such as waveform observation, thus improving testing efficiency.

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] The testing system provided in this application may include a first testing device and a second testing device; the first testing device will be described first in the following description. Figure 1 The diagram shown is a schematic diagram of an embodiment of a first testing device provided in this application. It may include an optical transmitter 101, a transmission optical fiber 102, a photonic integrated circuit chip 103, a photodetector 105, a signal generator 106, a high-frequency probe 107, and an oscilloscope 108. Specifically, the photonic integrated circuit chip 103 may be provided with an electro-optic modulator 104 to be tested.

[0039] A photonic integrated circuit chip, also known as a photonic chip, is a technology that miniaturizes and integrates photonic devices onto a special substrate material. These photonic devices can include, for example, gratings, waveguides, modulators, couplers, etc., which are combined to perform a specific function. In this embodiment, the photonic integrated circuit chip may contain an electro-optic modulator under test.

[0040] A signal generator, also known as a signal source or oscillator, is a device capable of providing electrical signals of various frequencies, waveforms, and output levels. It has wide applications in production practices and scientific fields. As an optional implementation, a signal generator can employ a function generator. Function generators can produce various waveforms such as sine waves, square waves, triangle waves, and sawtooth waves, with a wide frequency range, and are widely used in scientific fields such as production testing, instrument repair, and laboratories.

[0041] A high-frequency probe is a probe that transmits high-frequency alternating current signals. As an optional implementation, a high-frequency probe can be a GSG probe, which is a probe used for electronic testing and measurement. It can perform precise measurements in the high-frequency range and is commonly used to test high-frequency circuits, microwave circuits, and radio frequency circuits. It has wide applications in fields such as radio communication, satellite navigation, radar, wafer testing, and microwave communication.

[0042] An oscilloscope is an instrument used to measure the shape of alternating current or pulse current waves. It can be composed of a vacuum tube amplifier, a scanning oscillator, a cathode ray tube, etc.

[0043] A photodetector is an instrument that converts optical signals into electrical signals. As an optional implementation, a PIN photodetector can be used. PIN photodetectors are composed of P-type, I-type, and N-type semiconductors and have advantages such as fast response speed, low dark current, and low noise. They are widely used in fields such as fiber optic communication, lidar, and spectral analysis.

[0044] Specifically, the signal generator 106 can be connected to the photonic integrated circuit chip 103 via the high-frequency probe 107. The signal generator 106 can output an adjustable high-frequency AC signal, which is transmitted to the photonic integrated circuit chip 103 via the high-frequency probe 107 to provide a first modulation voltage for the electro-optic modulator 104 under test on the photonic integrated circuit chip 103.

[0045] Furthermore, the optical transmitter 101 can be connected to one end of the photonic integrated circuit chip 103 via the transmission optical fiber 102, and the other end of the photonic integrated circuit chip 103 can be connected to the photodetector 105 via the transmission optical fiber 102. The photodetector 105 is connected to the oscilloscope 108. The optical signal emitted by the optical transmitter 101 can be transmitted to the photonic integrated circuit chip 103 via the transmission optical fiber 102. The electro-optic modulator 104 under test can perform phase modulation on the optical signal under the action of the first modulation voltage. The modulated optical signal is transmitted to the photodetector 105 via the transmission optical fiber 102. After being converted into an electrical signal by the photodetector 105, it is transmitted to the oscilloscope 108. The oscilloscope 108 can perform tests based on the electrical signal and determine that the first modulation voltage corresponding to the electro-optic modulator 104 under test is a half-wave voltage based on the first test result.

[0046] When the first modulation voltage corresponding to the electro-optic modulator 104 under test is a half-wave voltage, the first source voltage is determined. The first source voltage can refer to the total voltage corresponding to the modulation signal provided to the electro-optic modulator under test. In the first test device, the signal generator has an output impedance, and its output impedance and the electro-optic modulator under test are used to divide the voltage. The modulation voltage applied to the electro-optic modulator under test is obtained by dividing the first source voltage.

[0047] like Figure 2 The diagram shown is a schematic of an embodiment of a second testing device provided in this application. It may include an optical transmitter 101, a transmission optical fiber 102, a photonic integrated circuit chip 103, an optical power tester 205, a source measurement unit 206, a DC probe 207, and a resistive element 208. Specifically, the photonic integrated circuit chip 103 may be provided with an electro-optic modulator 104 to be tested.

[0048] A source measurement unit (SMU), also known as a source meter, is a multi-functional testing device that combines measurement and source functions. A source measurement unit can add current and / or voltage source functionality to testing instruments, and can also acquire and measure voltage and / or current values.

[0049] A DC probe is a probe that transmits a DC electrical signal.

[0050] A resistor is a resistor with a specific resistance value.

[0051] An optical power tester is an instrument used to measure the magnitude of optical power. As an optional implementation, an optical power tester can be an optical power meter.

[0052] Specifically, the source measurement unit 206 can be connected to one end of the resistor element 208, and the other end of the resistor element 208 is connected to the photonic integrated circuit chip 103 via the DC probe 207. The source measurement unit 206 can output an adjustable DC signal, which is transmitted to the photonic integrated circuit chip 103 via the resistor element 208 and the DC probe 207 to provide a second modulation voltage for the electro-optic modulator 104 under test. The sum of the resistance values ​​of the resistor element 208, the DC probe contact resistance, and the wire resistance can be consistent with the output impedance of the signal generator 106 in the first test device, for example, it can be 50 ohms.

[0053] Furthermore, the optical transmitter 101 can be connected to one end of the photonic integrated circuit chip 103 via the transmission optical fiber 102, and the other end of the photonic integrated circuit chip 103 can be connected to the optical power tester 205 via the transmission optical fiber 102. The optical signal emitted by the optical transmitter 101 is transmitted to the photonic integrated circuit chip 103 via the transmission optical fiber 102. The electro-optic modulator under test 104 can perform phase modulation on the optical signal under the action of the second modulation voltage. The modulated optical signal is transmitted to the optical power tester 205 via the transmission optical fiber. The optical power tester 205 can test the modulated optical signal and determine that the second modulation voltage corresponding to the electro-optic modulator under test 104 is a half-wave voltage based on the second test result.

[0054] When the second modulation voltage corresponding to the electro-optic modulator 104 under test is a half-wave voltage, the second source voltage is determined. The second source voltage can refer to the total voltage corresponding to the modulation signal provided to the electro-optic modulator under test. In the second test device, the resistive element, the DC probe contact resistance, and the wire resistance are combined with the electro-optic modulator under test to divide the voltage. The modulation voltage applied to the electro-optic modulator under test is obtained by dividing the second source voltage.

[0055] After obtaining the first and second source voltages, their values ​​can be compared. If the first and second source voltages are consistent, it indicates that the voltage division caused by the resistive element, DC probe contact resistance, and wire resistance when testing the half-wave voltage based on a DC signal is consistent with the voltage division caused by the output impedance of the signal generator when testing the half-wave voltage based on a high-frequency AC signal. This indicates that the voltage applied to the electro-optic modulator under test is consistent; that is, the half-wave voltage of the electro-optic modulator under test obtained based on the DC signal provided by the source measurement unit is consistent with the half-wave voltage obtained based on the high-frequency AC signal provided by the signal generator. In this case, the DC signal can be used to provide the modulation voltage for the electro-optic modulator under test and perform the half-wave voltage test, instead of using the high-frequency AC signal to provide the modulation voltage. Otherwise, the half-wave voltages obtained by the two tests are inconsistent.

[0056] In this embodiment, the testing system may include a first testing device and a second testing device. In the first testing device, a first modulation voltage is provided to the electro-optic modulator under test using a high-frequency alternating current signal. When the applied first modulation voltage is determined to be a half-wave voltage, a first source voltage is determined. In the second testing device, which is equipped with a resistive element, a second modulation voltage is provided to the electro-optic modulator under test using a direct current signal. When the applied second modulation voltage is determined to be a half-wave voltage, a second source voltage is determined. The first source voltage and the second source voltage are compared. If the first source voltage and the second source voltage are consistent, it indicates that the electro-optic modulator is based on a direct current signal. When testing the half-wave voltage, the voltage division by the resistive element, the DC probe contact resistance, and the wire resistance is consistent with the voltage division by the output impedance of the signal generator when testing the half-wave voltage based on a high-frequency AC signal. This indicates that the voltage applied to the electro-optic modulator under test is consistent, meaning that the half-wave voltages measured by the two methods are consistent. Therefore, a DC signal can be used to provide a modulation voltage to the electro-optic modulator under test for half-wave voltage testing, instead of using a high-frequency AC signal to provide the modulation voltage. This eliminates the need for complex testing instruments such as signal generators and oscilloscopes, as well as complex testing processes such as waveform observation, thus improving testing efficiency.

[0057] In some embodiments, the oscilloscope can be used to determine that the first modulation voltage corresponding to the electro-optic modulator under test is the half-wave voltage when the amplitude of the waveform corresponding to the electrical signal is at its maximum. The specific test process can refer to the process of testing the half-wave voltage using a high-frequency AC electrical signal in the traditional scheme, and will not be repeated here.

[0058] In some embodiments, the optical power tester can be used to determine that the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage when the power of the optical signal is at its minimum. The specific test process can be referred to the process of testing the half-wave voltage using a DC signal, and will not be repeated here.

[0059] In some embodiments, the optical power tester may include a power sensor for converting a high-frequency test signal of the optical signal into a low-frequency test signal and testing the power of the low-frequency test signal.

[0060] Optionally, the optical power tester may also include a display for showing the power.

[0061] In some embodiments, the high-level voltage of the signal generator can be adjusted to output a corresponding high-frequency AC signal.

[0062] At this point, the first source voltage can be determined based on the high-level voltage of the signal generator when the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage.

[0063] Specifically, the high-level voltage of the signal generator can be adjusted to provide different first modulation voltages to the electro-optic modulator under test. Under the action of different first modulation voltages, the optical signal is phase-modulated. The waveform corresponding to the electrical signal converted from the modulated optical signal is observed by an oscilloscope. When the waveform amplitude is the largest, the first modulation voltage currently applied to the electro-optic modulator under test is the half-wave voltage. The first source voltage is determined based on the current high-level voltage of the signal generator. For example, the high-level voltage can be multiplied by a preset coefficient to obtain the first source voltage. This can be set according to the actual application scenario.

[0064] In some embodiments, the voltage of the source measurement unit can be adjusted to output a corresponding DC signal.

[0065] At this point, the second source voltage can be determined based on the voltage of the source measurement unit when the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage.

[0066] Specifically, the voltage of the source measurement unit can be adjusted to provide different second modulation voltages to the electro-optic modulator under test. Under the action of different second modulation voltages, the optical signal is phase-modulated. The power of the modulated optical signal is tested by the optical power tester. When the power is initially at its minimum, the second modulation voltage currently applied to the electro-optic modulator under test is determined to be a half-wave voltage. The second source voltage is determined based on the current voltage of the source measurement unit. For example, the voltage of the source measurement unit can be directly used as the second source voltage.

[0067] In some embodiments, the light emitter may include a laser. The wavelength and power of the laser can be preset. For example, the spectrum can be scanned to find a peak wavelength near 1310 nm, and this peak wavelength can be set as the wavelength of the laser. The laser power can also be set to 10 dBm, etc.

[0068] In some embodiments, the transmission optical fiber may include a polarization-maintaining fiber array. A polarization-maintaining fiber array is a fiber array (FA) that can maintain a constant polarization state. It is an array formed by mounting a bundle of optical fibers or a fiber ribbon on a V-groove substrate at preset intervals. An array formed by polarization-maintaining fibers is called a polarization-maintaining fiber array.

[0069] Optionally, the photonic integrated circuit chip may include a grating coupler, and the transmission optical fiber may be coupled to the grating coupler to achieve coupling connection with the photonic integrated circuit chip.

[0070] This application also provides a testing method that can be applied to... Figure 1 and Figure 2 The specific implementation of the test device shown has been described in the foregoing embodiments and will not be repeated here.

[0071] Those skilled in the art will clearly understand that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any inventive effort.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A testing system, characterized in that, It includes a first testing device and a second testing device. The first testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, a photodetector, a signal generator, a high-frequency probe, and an oscilloscope. The photonic integrated circuit chip is provided with an electro-optic modulator under test. The signal generator is connected to the photonic integrated circuit chip via the high-frequency probe. The signal generator outputs an adjustable high-frequency AC signal, which is transmitted to the photonic integrated circuit chip via the high-frequency probe to provide a first modulation voltage for the electro-optic modulator under test. The optical transmitter is connected to one end of the photonic integrated circuit chip via the transmission optical fiber, and the other end of the photonic integrated circuit chip is connected to the photodetector via the transmission optical fiber. The photodetector is connected to the oscilloscope. The optical signal emitted by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. Under the action of the first modulation voltage, the electro-optic modulator under test modulates the phase of the optical signal. The modulated optical signal is transmitted to the photodetector via the transmission optical fiber, converted into an electrical signal by the photodetector, and then transmitted to the oscilloscope. The oscilloscope performs tests based on the electrical signal and determines the first modulation voltage corresponding to the electro-optic modulator under test as a half-wave voltage based on the first test result. When the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the first source voltage is determined; The second testing device includes an optical transmitter, a transmission optical fiber, a photonic integrated circuit chip, an optical power tester, a source measurement unit, a DC probe, and a resistive element. The photonic integrated circuit chip contains an electro-optic modulator under test. The source measurement unit is connected to one end of the resistive element, and the other end of the resistive element is connected to the photonic integrated circuit chip through the DC probe. The source measurement unit outputs an adjustable DC signal, which is transmitted to the photonic integrated circuit chip through the resistive element and the DC probe to provide a second modulation voltage for the electro-optic modulator under test. The sum of the resistance values ​​of the resistive element, the DC probe contact resistance, and the wire resistance is consistent with the output impedance of the signal generator. The optical transmitter is connected to one end of the photonic integrated circuit chip via the transmission optical fiber, and the other end of the photonic integrated circuit chip is connected to the optical power tester via the transmission optical fiber. The optical signal emitted by the optical transmitter is transmitted to the photonic integrated circuit chip via the transmission optical fiber. The electro-optic modulator under test modulates the phase of the optical signal under the action of the second modulation voltage. The modulated optical signal is transmitted to the optical power tester via the transmission optical fiber. The optical power tester tests the modulated optical signal and determines that the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage based on the second test result. When the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the second source voltage is determined; If the first source voltage and the second source voltage are consistent, it is determined that the half-wave voltage of the electro-optic modulator under test obtained by testing the DC signal provided by the source measurement unit is consistent with the half-wave voltage of the electro-optic modulator under test obtained by testing the high-frequency AC signal provided by the signal generator; otherwise, they are inconsistent.

2. The system according to claim 1, characterized in that, Specifically, the oscilloscope is used to determine that the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage when the amplitude of the waveform corresponding to the electrical signal is at its maximum.

3. The system according to claim 1, characterized in that, The optical power tester is specifically used to determine that the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage when the power of the optical signal is at its minimum.

4. The system according to claim 3, characterized in that, The optical power tester includes a power sensor for converting the high-frequency test signal of the optical signal into a low-frequency test signal and testing the power of the low-frequency test signal.

5. The system according to claim 4, characterized in that, The optical power tester also includes a display for showing the power.

6. The system according to claim 1, characterized in that, The high-level voltage of the signal generator is adjustable to output a corresponding high-frequency AC signal; When the first modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the first source voltage is determined based on the high-level voltage of the signal generator.

7. The system according to claim 1, characterized in that, The voltage of the source measurement unit is adjustable to output a corresponding DC signal; When the second modulation voltage corresponding to the electro-optic modulator under test is a half-wave voltage, the second source voltage is determined based on the voltage of the source measurement unit.

8. The system according to claim 1, characterized in that, The light emitter includes a laser, the wavelength and power of which are preset.

9. The system according to claim 1, characterized in that, The transmission optical fiber includes a polarization-maintaining fiber array.

10. A testing method, characterized in that, Applied to the test system as described in any one of claims 1-9.

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