Photoelectric S parameter testing device and system and de-embedding method

Abstract

The invention provides a photoelectric S parameter testing device and system and a de-embedding method. The photoelectric S parameter testing device comprises a vector network analyzer and an optical signal generation module, the vector network analyzer provides a radio frequency signal for the optical signal generation module and receives a test electric signal output by the device to be tested; the optical signal generation module generates a modulated optical signal based on the radio frequency signal; wherein the optical signal generation module comprises a light source, a driving unit and a modulator; the light source provides light signals. The driving unit receives a radio frequency signal and generates a modulation signal of the modulator based on the radio frequency signal; the modulator receives the optical signal and modulates the optical signal under the action of the modulation signal. The photoelectric S parameter testing device and the photoelectric S parameter testing system can replace commercial instruments, are small in error, can meet testing and using requirements, and are low in cost.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a photoelectric S parameter testing device, system and de-embedding method. Background Art

[0002] S parameters (full name Scatter parameters), or scattering parameters, are defined under the condition that there are terminals at both ends of the transmission line, usually with a terminal impedance of 50Ω; S parameters are used to describe the incidence, reflection, and transmission characteristics of signals in the circuit, and provide a simplified circuit characterization method by analyzing the behavior of signals at different ports. S parameter measurements from optical input to electrical output are usually used to describe the frequency response characteristics of optoelectronic devices; specifically, they are achieved by measuring the frequency-dependent transfer characteristics of the device from optical signals (input) to electrical signals (output).

[0003] like Figure 1 As shown, the conventional S parameter measurement device 1 from optical input to electrical output is generally provided directly by the instrument manufacturer, and a vector network analyzer 11 drives an optical base 12 to generate the modulated light required for the test and input it into the device under test 2, and finally the output of the device under test 2 is returned to the electrical input interface of the vector network analyzer 11; the optical base 12 is used in combination with the vector network analyzer 11 to provide accurate measurement and analysis of optoelectronic components. The biggest challenge of this test solution is that the price of the optical base 12 is very high, often costing several million RMB.

[0004] Therefore, how to reduce the test cost while ensuring the accuracy of S parameter testing has become one of the urgent problems to be solved by those skilled in the art.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an optoelectronic S parameter testing device, system and de-embedding method, so as to solve the problem of high cost of the S parameter testing device in the prior art.

[0007] To achieve the above-mentioned object and other related objects, the present invention provides a photoelectric S parameter testing device, which at least includes: A vector network analyzer and an optical signal generating module; the vector network analyzer provides a radio frequency signal to the optical signal generating module and receives a test electrical signal output by the device under test; the optical signal generating module generates a modulated optical signal based on the radio frequency signal; Wherein, the optical signal generating module includes a light source, a driving unit and a modulator; The light source provides a light signal; The driving unit receives the radio frequency signal and generates a modulation signal of the modulator based on the radio frequency signal; The modulator receives the optical signal and modulates the optical signal under the action of the modulation signal.

[0008] Optionally, the light source is a continuous wave laser.

[0009] More optionally, the modulator is a Mach-Zehnder modulator.

[0010] More optionally, the test range of the optoelectronic S parameter test device is less than or equal to 40 GHz.

[0011] To achieve the above-mentioned object and other related objects, the present invention further provides an optoelectronic S parameter testing system, the optoelectronic S parameter testing system at least comprising: Device under test and the above-mentioned optoelectronic S parameter testing device; The device under test receives the modulated optical signal provided by the optoelectronic S parameter testing device, and generates a corresponding test electrical signal based on the modulated optical signal; The optoelectronic S parameter testing device receives the test electrical signal, and compares and analyzes the test electrical signal with the radio frequency signal to obtain the S parameters of the device under test.

[0012] Optionally, the wavelength of the optical signal output by the light source in the optoelectronic S parameter testing device matches the operating wavelength of the device under test.

[0013] Optionally, the device under test is a photodetector.

[0014] More optionally, the device under test further includes a transimpedance amplifier connected to an output end of the photodetector.

[0015] To achieve the above object and other related objects, the present invention further provides a method for de-embedding an S parameter, the method for de-embedding an S parameter at least comprising: Based on a vector network analyzer, the S parameters of the optical signal generating module and the fixture are measured separately; the fixture is located between the device under test and the vector network analyzer; Based on the above-mentioned optoelectronic S parameter test system, obtaining the total S parameter; The inverse matrix method is used to remove the influence of the optical signal generation module and the fixture, and the S parameters of the device under test are obtained.

[0016] Optionally, the inverse matrix method satisfies: ; in, is the S parameter of the device under test; is the S parameter of the optical signal generation module; is the total S parameter; is the S parameter of the fixture.

[0017] As described above, the optoelectronic S parameter testing device, system and de-embedding method of the present invention have the following beneficial effects: The photoelectric S parameter test device and system of the present invention can replace commercial instruments and be used to test the most important bandwidth and flatness indicators in the photoelectric S parameters; after the de-embedding operation, the measurement results of the present invention are basically consistent with those of the commercial instruments, with a very small error, which can meet the test requirements; and the cost of the photoelectric S parameter test device of the present invention is 1% of that of the commercial instruments, which greatly saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shown is a schematic diagram of the structure of a commercial S-parameter measurement instrument.

[0019] Figure 2 Shown is a schematic structural diagram of the optoelectronic S parameter testing device of the present invention.

[0020] Figure 3 Shown is a structural schematic diagram of the optoelectronic S parameter testing system of the present invention.

[0021] Figure 4 It is a schematic diagram showing the principle of the de-embedding method of the present invention.

[0022] Figure 5 It is a schematic diagram of the S parameter curve of the optical signal generating module of the present invention.

[0023] Figure 6 It is a schematic diagram of the total S parameter curve of the optical signal generating module, the device under test and the fixture (or connector) of the present invention.

[0024] Figure 7 Shown is a schematic diagram of the total S parameter curve of the device under test after de-embedding according to the present invention.

[0025] Component number description 1-S parameter measuring device; 11-vector network analysis device; 12-optical base; 2-device under test; 3-photoelectric S parameter testing device; 31-vector network analyzer; 32-optical signal generating module; 321-light source; 322-driving unit; 323-modulator; 4-device under test; 5-fixture or connector. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] See also Figure 2~Figure 7 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0028] like Figure 2 As shown, the present invention provides a photoelectric S parameter testing device 3, and the photoelectric S parameter testing device 3 includes: A vector network analyzer 31 and an optical signal generating module 32 .

[0029] like Figure 2 As shown, the vector network analyzer 31 provides a radio frequency signal to the optical signal generating module 32 and receives a test electrical signal output by the device under test.

[0030] Specifically, the vector network analyzer 31 (VNA) is an instrument for measuring radio frequency (RF) and microwave signals, and is mainly used to measure the S parameters of the device, including amplitude and phase response, to evaluate and analyze the performance of the device under test. The vector network analyzer 31 provides the RF signal required for the test, receives the test electrical signal, and performs analysis and calculation based on the RF signal and the test electrical signal to obtain the S parameters of the device under test. As an example, the vector network analyzer 31 includes a signal source for generating the RF signal required for the test (the RF signal output from the electrical signal output terminal), a test port for connecting to the device under test (i.e., the electrical signal input terminal), a receiver for receiving and processing the output signal of the device under test, a processor for mathematically processing the received signal and calculating the network parameters, and a display for displaying the measurement results.

[0031] like Figure 2As shown, the optical signal generating module 32 generates a modulated optical signal based on the radio frequency signal.

[0032] Specifically, the optical signal generating module 32 includes a light source 321 , a driving unit 322 and a modulator 323 .

[0033] Among them, the light source 321 is used to provide an optical signal. As an example, the light source 321 is a continuous wave (CW) laser, which achieves stable laser output through continuous excitation energy. The continuous wave laser has a lower peak power and a higher average power. In actual use, any type of light source that can provide the optical signal required for S parameter testing is applicable to the present invention, and is not limited to this embodiment.

[0034] The driving unit 322 receives the RF signal and generates a modulation signal of the modulator 323 based on the RF signal. In this example, the driving unit 322 amplifies the amplitude of the RF signal to obtain a modulation signal sufficient to modulate the optical signal in the modulator 323.

[0035] The modulator 323 receives the optical signal and modulates the optical signal under the action of the modulation signal. As an example, the modulator 323 is set as a Mach-Zehnder Modulator (MZM), which divides the input optical signal into two equal signals and enters two optical branches respectively. The materials used in these two optical branches are electro-optical materials, and their refractive index varies with the size of the externally applied electrical signal (radio frequency signal); since the refractive index change of the optical branch will cause the change of the signal phase, when the optical signals output by the two optical branches are combined again, the synthesized optical signal will be an interference signal with varying intensity, which is equivalent to converting the change of the electrical signal into the change of the optical signal, thereby realizing the modulation of the light intensity. In actual use, any modulator structure that can load the change of the electrical signal onto the optical signal to obtain a modulated optical signal is applicable to the present invention, and is not limited to this embodiment.

[0036] like Figure 3 As shown, the present invention further provides an optoelectronic S parameter testing system, which includes: an optoelectronic S parameter testing device 3 of the present invention and a device under test (DUT) 4.

[0037] like Figure 3 As shown, the device under test 4 receives the modulated optical signal provided by the optoelectronic S parameter testing device 3, and generates a corresponding test electrical signal based on the modulated optical signal.

[0038] Specifically, the device under test 4 is a combination of a photodetector (PD) or other photoelectric conversion devices, including but not limited to a combination of a photodetector and a transimpedance amplifier, the transimpedance amplifier is connected to the output end of the photodetector to amplify the output signal of the photodetector. Any device, module and equipment that can convert an optical signal into an electrical signal is applicable to the present invention, and will not be described in detail here.

[0039] like Figure 3 As shown, the optoelectronic S parameter testing device 3 receives the test electrical signal, and compares and analyzes the test electrical signal with the radio frequency signal to obtain the S parameters of the device under test 4.

[0040] Specifically, the structure of the optoelectronic S parameter test device 3 is as described above, and will not be described here one by one. The wavelength of the optical signal output by the light source 321 in the optoelectronic S parameter test device 3 matches the working wavelength of the device under test 4. For example, if the working wavelength of the device under test 4 is 1310nm, the wavelength of the optical signal output by the light source 321 is also set to 1310nm; or, both are configured to 1550nm, which are not listed here one by one.

[0041] Specifically, since the frequency response of the optical signal generating module 32 is not flat, the vector network analyzer 31 in the optoelectronic S parameter test device 3 also performs a "de-embedding" function when performing S parameter testing; the purpose of "de-embedding" is to remove the influence of non-DUT (device under test) parts such as test fixtures or connectors from the measurement results, thereby obtaining the true electrical characteristics of the device under test 4. Figure 4 As shown, the electrical signal output by the vector network analyzer 31 passes through the optical signal generating module 32, the device under test 4, the fixture (or connector) 5 and then returns to the vector network analyzer 31. The S parameter curve obtained by the vector network analyzer 31 includes the S parameters of the optical signal generating module 32, the S parameters of the device under test 4 and the S parameters of the fixture (or connector) 5, wherein the S parameters of the optical signal generating module 32 and the fixture (or connector) 5 need to be removed by de-embedding.

[0042] De-embedding specifically includes the following steps: 1) Based on the vector network analyzer 31, the S parameters of the optical signal generating module 32 and the fixture (or connector) 5 are measured separately, and the optical signal generating module 32 and the fixture (or connector) 5 are respectively equivalent to two embedded networks, one at the input side of the device under test 4 and the other at the output side of the device under test 4. Figure 5 The figure shows the S parameter curve of the optical signal generating module 32. In this example, the bandwidth can reach about 45 GHz, and the inflection point is at 40 GHz, indicating that the optoelectronic S parameter testing device 3 of the present invention can test optoelectronic S parameters within 40 GHz.

[0043] 2) Obtain the total S parameters of the optical signal generating module 32, the device under test 4 and the fixture (or connector) 5 based on the optoelectronic S parameter test system of the present invention. Figure 6 The overall S-parameter curve is shown, with a bandwidth of about 16 GHz and a 2 dB peak at 5.79 GHz.

[0044] 3) Apply the inverse matrix method to remove the influence of the optical signal generating module 32 and the fixture (or connector) 5. The formula is as follows: ; in, is the S parameter of the device under test 4; is the S parameter of the optical signal generating module 32; is the total S parameter of the optical signal generating module 32, the device under test 4 and the fixture (or connector) 5; is the S parameter of the output fixture (or connector) 5.

[0045] like Figure 7 The figure shows the S parameter curve of the device under test 4 after de-embedding. It can be seen that the S parameter curve is flatter (the peak becomes flatter). In addition, the S parameters of the device under test 4 are measured using commercial instruments. It is found that the error between the measurement result of the optoelectronic S parameter test device 3 of the present invention and the measurement result of the commercial instrument is less than 0.5db, which meets the test requirements.

[0046] It should be noted that there is no strict order between step 1) and step 2), and step 1) and step 2) can be completed before step 3).

[0047] In summary, the present invention provides an optoelectronic S parameter test device, system and de-embedding method, including: a vector network analyzer and an optical signal generating module; the vector network analyzer provides a radio frequency signal to the optical signal generating module, and receives the test electrical signal output by the device to be tested; the optical signal generating module generates a modulated optical signal based on the radio frequency signal; wherein the optical signal generating module includes a light source, a driving unit and a modulator; the light source provides an optical signal; the driving unit receives the radio frequency signal, and generates a modulated signal of the modulator based on the radio frequency signal; the modulator receives the optical signal, and modulates the optical signal under the action of the modulated signal. The optoelectronic S parameter test device and system of the present invention can replace commercial instruments, have very small errors, can meet the test use requirements, and have low cost. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0048] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A photoelectric S parameter testing device, characterized in that: The photoelectric S parameter testing device at least comprises: A vector network analyzer and an optical signal generating module; the vector network analyzer provides a radio frequency signal to the optical signal generating module and receives a test electrical signal output by the device under test; the optical signal generating module generates a modulated optical signal based on the radio frequency signal; Wherein, the optical signal generating module includes a light source, a driving unit and a modulator; The light source provides a light signal; The driving unit receives the radio frequency signal and generates a modulation signal of the modulator based on the radio frequency signal; The modulator receives the optical signal and modulates the optical signal under the action of the modulation signal.

2. The photoelectric S parameter test device according to claim 1, characterized in that: The light source is a continuous wave laser.

3. The photoelectric S parameter testing device according to claim 1 or 2, characterized in that: The modulator is a Mach-Zehnder modulator.

4. The photoelectric S parameter test device according to claim 1 or 2, characterized in that: The test range of the optoelectronic S parameter test device is less than or equal to 40 GHz.

5. An optoelectronic S parameter test system, characterized in that: The photoelectric S parameter test system at least includes: A device under test and an optoelectronic S parameter testing device as claimed in any one of claims 1 to 4; The device under test receives the modulated optical signal provided by the optoelectronic S parameter testing device, and generates a corresponding test electrical signal based on the modulated optical signal; The optoelectronic S parameter testing device receives the test electrical signal, and compares and analyzes the test electrical signal with the radio frequency signal to obtain the S parameters of the device under test.

6. The optoelectronic S parameter test system according to claim 5, characterized in that: The wavelength of the optical signal output by the light source in the photoelectric S parameter testing device matches the working wavelength of the device under test.

7. The optoelectronic S parameter test system according to claim 6, characterized in that: The device under test is a photoelectric detector.

8. The optoelectronic S parameter test system according to claim 7, characterized in that: The device under test also includes a transimpedance amplifier connected to the output end of the photodetector.

9. A method for de-embedding photoelectric S parameters, characterized in that: The de-embedding method of the optoelectronic S parameters at least comprises: Based on a vector network analyzer, the S parameters of the optical signal generating module and the fixture are measured separately; the fixture is located between the device under test and the vector network analyzer; Based on the optoelectronic S parameter test system according to any one of claims 5 to 8, obtaining total S parameters; The inverse matrix method is applied to remove the influence of the optical signal generating module and the fixture to obtain the S parameters of the device under test.

10. The method for de-embedding optoelectronic S parameters according to claim 9, characterized in that: The inverse matrix method satisfies: ； in, is the S parameter of the device under test; is the S parameter of the optical signal generating module; is the total S parameter; is the S parameter of the fixture.

Images