A segmented polarity detection device for the signal transmission path of a PAM4 optical module

Abstract

This application relates to the field of optical communication technology, and more particularly to a segmented polarity detection device for the signal transmission path of a PAM4 optical module, comprising a bit error rate tester, a power divider, a beam splitter, a signal display, and a test board; the detection signal output terminal of the bit error rate tester is connected to the input terminal of the power divider; the first signal output terminal of the power divider is connected to the first signal input terminal of the signal display; the second signal output terminal of the power divider is connected to the input terminal of the test board, and the output terminal of the test board is connected to the second signal input terminal of the signal display; the beam splitter includes an input terminal connected to the optical transmitter of the PAM4 optical module, a third signal output terminal connected to the optical receiver of the PAM4 optical module, and a fourth signal output terminal connected to the third signal input terminal of the signal display; the signal display is used to display the code patterns of the signals input to the first, second, and third signal input terminals. This device can effectively detect potential polarity errors in the signal transmission path of the PAM4 optical module.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a segmented polarity detection device for the signal transmission path of a PAM4 optical module. Background Technology

[0002] With the surge in demand for information transmission, PAM4 optical modules are widely used in data centers, telecommunications networks, AI computing clusters, and many other fields. The accuracy of their information transmission impacts the entire communication system. A PAM4 optical module is an optical communication module that uses Pulse Amplitude Modulation (PAM) technology. It typically includes a DSP chip, a photoelectric conversion module, and an electro-optical conversion module. When used as a receiver, the photoelectric conversion module converts the received optical signal into an electrical signal, which is then input to the DSP chip for demodulation. The demodulated differential electrical signal (signals of equal amplitude but opposite polarity) is output from the electrical signal output terminal. When used as a transmitter, the DSP chip modulates the differential electrical signal input from the electrical signal input terminal, converts the modulated differential electrical signal into an optical signal via the electro-optical conversion module, and outputs it from the optical signal transmitter. In the above signal transmission path of the PAM4 optical module, each input or output port of the DSP chip typically includes two pins for inputting or outputting a set of differential electrical signals with positive and negative polarities. During the wiring and debugging of the various components of the PAM4 optical module, the polarity of two pins may sometimes be reversed, requiring the use of a polarity detection device for testing.

[0003] Existing polarity detection devices typically only focus on the correctness of the input and output of the PAM4 optical module as a whole device, neglecting polarity connection errors between components within the entire detection loop. For example, when testing the PAM4 optical module's function as a transmitter, existing technology inputs the preset detection signal from the bit error rate tester (BERT) into the PAM4 optical module, loops the short fiber of the module, and directly observes the BERT to determine the polarity of the PAM4 optical module. However, polarity connection errors between different components of the PAM4 optical module, combined with polarity errors in the BERT device, can achieve a "negative times negative equals positive" effect, failing to adequately detect potential polarity errors in the PAM4 optical module's signal transmission path. This is particularly problematic for PAM4 optical modules that claim to support OIF CMIS protocol module diagnostic monitoring functions. Since this protocol involves the PAM4 optical module's self-generated code and detection code pattern functions, polarity errors between components can lead to communication failures, preventing the PAM4 optical module from functioning properly. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a segmented polarity detection device for the signal transmission path of a PAM4 optical module, which solves the technical problem that the prior art cannot fully detect the possible polarity errors in the signal transmission path of a PAM4 optical module.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted in this application include:

[0008] This application provides a segmented polarity detection device for the signal transmission path of a PAM4 optical module, including: a bit error rate tester, a power divider, a beam splitter, a signal display, and a test board for mounting the PAM4 optical module;

[0009] The detection signal output terminal of the bit error rate tester is connected to the input terminal of the power divider;

[0010] The first signal output terminal of the power divider is connected to the first signal input terminal of the signal display; the second signal output terminal of the power divider is connected to the input terminal of the test board, and the output terminal of the test board is connected to the second signal input terminal of the signal display.

[0011] The beam splitter includes: an input terminal for connecting to the optical transmitter of the PAM4 optical module, a third signal output terminal for connecting to the optical receiver of the PAM4 optical module, and a fourth signal output terminal for connecting to the third signal input terminal of the signal display.

[0012] The signal display is used to display the code patterns of the signals input from the first signal input terminal, the second signal input terminal, and the third signal input terminal.

[0013] Optionally, in some embodiments of this application, the signal display is a photoelectric sampling oscilloscope;

[0014] The first and second signal input terminals of the photoelectric sampling oscilloscope are electrical signal sampling terminals, and the third signal input terminal of the photoelectric sampling oscilloscope is an optical signal sampling terminal.

[0015] Optionally, in some embodiments of this application, the clock signal output terminal of the bit error rate tester is connected to the trigger terminal of the photoelectric sampling oscilloscope.

[0016] Optionally, in some embodiments of this application, the detection signal output terminal of the bit error rate tester includes a TX+ output terminal and a TX- output terminal, and the power divider includes a first sub-power divider and a second sub-power divider;

[0017] The TX+ output terminal is connected to the input terminal of the first sub-power divider, and the TX- output terminal is connected to the input terminal of the second sub-power divider.

[0018] Optionally, in some embodiments of this application, the fifth signal output terminal of the first sub-power divider is connected to the first signal input terminal of the signal display, and the seventh signal output terminal of the second sub-power divider is grounded through a first matching resistor.

[0019] Optionally, in some embodiments of this application, the input terminals of the test board include a TX+ input terminal and a TX- input terminal; the TX+ input terminal is connected to the sixth output terminal of the first sub-power divider, and the TX- input terminal is connected to the eighth output terminal of the second sub-power divider.

[0020] Optionally, in some embodiments of this application, the output terminals of the test board include an RX+ output terminal and an RX- output terminal;

[0021] The RX+ output terminal is connected to the second signal input terminal of the signal display, and the RX- output terminal is grounded through the second matching resistor.

[0022] Optionally, in some embodiments of this application, the resistance values ​​of the first matching resistor and the second matching resistor are both 50Ω.

[0023] Optionally, in some embodiments of this application, the test board includes a connector for electrically connecting to the electrical signal input and electrical signal output terminals of the PAM4 optical module.

[0024] (III) Beneficial Effects

[0025] The beneficial effects of this application are as follows: The segmented polarity detection device provided by this application includes: a bit error rate tester, a power divider, a beam splitter, a signal display, and a test board for mounting a PAM4 optical module; the detection signal output terminal of the bit error rate tester is connected to the input terminal of the power divider; the first signal output terminal of the power divider is connected to the first signal input terminal of the signal display; the second signal output terminal of the power divider is connected to the input terminal of the test board, and the output terminal of the test board is connected to the second signal input terminal of the signal display; the beam splitter includes: an input terminal for connecting to the optical transmitter of the PAM4 optical module, a third signal output terminal for connecting to the optical receiver of the PAM4 optical module, and a fourth signal output terminal for connecting to the third signal input terminal of the signal display; the signal display is used to display the code patterns of the signals input to the first signal input terminal, the second signal input terminal, and the third signal input terminal.

[0026] Based on the aforementioned connection relationships of the bit error rate tester, power divider, optical splitter, signal display, and test board, the segmented polarity detection device provided in this application extracts signals from multiple connection nodes in the signal transmission path of the PAM4 optical module and displays the signal pattern at each connection node for user comparison. This allows for checking whether there are polarity connection errors between the internal components of the PAM4 optical module or between the bit error rate tester and the PAM4 optical module. This segmented detection of the PAM4 optical module's signal transmission path effectively detects potential polarity errors and ensures the normal operation of the PAM4 optical module. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a segmented polarity detection device for the signal transmission path of a PAM4 optical module in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the structure of a PAM4 optical module according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of the PAM4–Linearity code pattern;

[0030] Figure 4 Here is an example of the emission polarity detection results for a PAM4 optical module;

[0031] Figure 5 This is an example of the polarity detection result for the PAM4 optical module receiver.

[0032] [Explanation of Labels in the Attached Image]

[0033] 1. Bit error rate tester; 2. Power divider; 3. Test board; 4. Optical splitter; 5. Signal display; 6. Transmitting host segment; 7. Transmitting media segment; 8. Receiving media segment; 9. Receiving host segment. Detailed Implementation

[0034] To better explain and facilitate understanding of this application, the following detailed description of the application is provided in conjunction with the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] like Figure 1 As shown in the embodiment of this application, a segmented polarity detection device for the signal transmission path of a PAM4 optical module includes a bit error rate tester 1 (also known as a bit error rate tester, BERT), a power divider 2 (full name: power splitter), an optical splitter 4 (also known as an optical splitter), a signal display 5, and a test board 3 for mounting the PAM4 optical module (PAM4 Transceiver).

[0037] The detection signal output terminal of the bit error rate analyzer 1 is connected to the input terminal of the power divider 2. The first signal output terminal of the power divider 2 is connected to the first signal input terminal (input1) of the signal display 5; the second signal output terminal of the power divider 2 is connected to the input terminal of the test board 3, and the output terminal of the test board 3 is connected to the second signal input terminal (input2) of the signal display 5. The beam splitter 4 includes: an input terminal for connecting to the optical transmitter of the PAM4 optical module, a third signal output terminal for connecting to the optical receiver of the PAM4 optical module, and a fourth signal output terminal for connecting to the third signal input terminal (input3) of the signal display 5; the signal display 5 is used to display the code patterns of the signals input from the first signal input terminal (input1), the second signal input terminal (input2), and the third signal input terminal (input3).

[0038] Based on the above-mentioned connection relationship of the bit error rate tester 1, power divider 2, optical splitter 4, signal display 5, and test board 3, the segmented polarity detection device provided in this embodiment extracts signals from multiple connection nodes of the signal transmission path of the PAM4 optical module, and displays the code pattern of the signal at each connection node through the signal display 5 for the user to compare, so as to check whether there is a polarity connection error between the internal components of the PAM4 optical module, or between the bit error rate tester 1 and the PAM4 optical module, thereby performing segmented detection on the signal transmission path of the PAM4 optical module, fully detecting possible polarity errors in the signal transmission path of the PAM4 optical module, and ensuring the normal operation of the PAM4 optical module.

[0039] Furthermore, based on the aforementioned connection relationships of the bit error rate tester 1, power divider 2, beam splitter 4, signal display 5, and test board 3, the segmented polarity detection device provided in this embodiment can also complete the segmented detection of all signal transmission paths of the PAM4 optical module at one time. After the user inserts the PAM4 optical module into the test board, they can directly observe the consistency of the code pattern displayed on the signal display 5, which can greatly improve the detection efficiency.

[0040] In one specific embodiment of this example, the signal display 5 may be three signal displays 5 used to display the three signals of the first signal input terminal, the second signal input terminal and the third signal input terminal respectively, or it may be set as one signal display 5, which receives the above three signals through the three signal input terminals set on the same signal display 5, processes them respectively and displays them on the same display screen of the signal display 5 so that the user can compare the consistency of the code pattern.

[0041] Preferably, the signal display 5 is a photoelectric sampling oscilloscope, wherein the first and second signal input terminals of the photoelectric sampling oscilloscope are electrical signal sampling terminals, and the third signal input terminal of the photoelectric sampling oscilloscope is an optical signal sampling terminal. The signals collected by the first, second, and third signal input terminals of the photoelectric sampling oscilloscope can be displayed on the same screen, allowing the user to compare the consistency of the code patterns. It should be noted that photoelectric sampling oscilloscopes with both electrical signal sampling and optical signal sampling functions can directly use existing equipment; this application does not involve any improvement to the photoelectric sampling oscilloscope itself.

[0042] To achieve clock synchronization, the clock signal output terminal CLOCK of the bit error rate tester 1 can be connected to the trigger terminal of the photoelectric sampling oscilloscope, so that both operate based on the same clock reference and avoid test errors caused by timing differences.

[0043] In the second specific implementation of this embodiment, such as Figure 1 As shown, the detection signal output terminal of the bit error rate tester 1 includes a TX+ output terminal and a TX- output terminal. The TX+ output terminal of the bit error rate tester 1 is used to output a positive differential electrical signal, and the TX- output terminal is used to output a negative differential electrical signal. The positive and negative differential electrical signals together form the differential electrical signal used to input the PAM4 optical module.

[0044] The power divider 2 includes a first sub-power divider 201 and a second sub-power divider 202. The TX+ output terminal of the bit error rate analyzer 1 is connected to the input terminal of the first sub-power divider 201, and the TX- output terminal of the bit error rate analyzer 1 is connected to the input terminal of the second sub-power divider 202. The fifth signal output terminal of the first sub-power divider 201 is connected to the first signal input terminal of the signal display, and the seventh signal output terminal of the second sub-power divider 202 is grounded through a first matching resistor. The input terminals of the test board 3 include a TX+ input terminal and a TX- input terminal; the TX+ input terminal is connected to the sixth output terminal of the first sub-power divider 201, and the TX- input terminal is connected to the eighth output terminal of the second sub-power divider 202. Preferably, the first matching resistor has a resistance of 50Ω to ensure that the loads of the first sub-power divider 201 and the second sub-power divider 202 are consistent, thereby ensuring the signal quality in the detection loop formed by the segmented polarity detection device provided in this embodiment. Corresponding to the above connection method of the first sub-power divider 201 and the second sub-power divider 202, the first output terminal of the power divider 2 includes the fifth signal output terminal of the first sub-power divider 201, and the second signal output terminal of the power divider 2 includes the sixth signal output terminal of the first sub-power divider 201 and the eighth signal output terminal of the second sub-power divider.

[0045] Preferably, the first sub-power divider 201 and the second sub-power divider 202 are both Keysight N1027A-2P8.

[0046] The output terminals of the test board 3 include an RX+ output terminal and an RX- output terminal; the RX+ output terminal is connected to the second signal input terminal of the signal display 5, and the RX- output terminal is grounded through a second matching resistor. Similar to the first matching resistor, the second matching resistor has a resistance of 50Ω, used to ensure that the loads of the RX+ and RX- output terminals of the test board 3 are consistent, thereby ensuring the signal quality in the detection loop formed by the segmented polarity detection device provided in this embodiment.

[0047] In addition, to ensure that the PAM4 optical module can be easily connected to the segmented polarity detection device provided in this embodiment, the test board 3 may also include: a connector for electrically connecting to the electrical signal input terminal and electrical signal output terminal of the PAM4 optical module, and a power supply plug for connecting to an external power supply.

[0048] Example 2

[0049] This embodiment provides a detailed explanation of the detection principle and usage method of the segmented polarity detection device for the signal transmission path of the PAM4 optical module provided in Embodiment 1.

[0050] like Figure 2 As shown, the PAM4 optical module tested in this embodiment includes a DSP chip, a photoelectric conversion module, and an electro-optical conversion module. The electro-optical conversion module includes a laser driver and a laser. Its input is connected to the DSP chip to receive the differentially modulated signal. The output is the optical transmitter (TX) of the PAM4 optical module, connected to the fiber optic cable, and outputs an optical signal. The photoelectric conversion module includes a photodiode (PIN) and a transimpedance amplifier (TIA). Its input is the optical receiver (RX) of the PAM4 optical module, connected to the fiber optic cable. The photoelectric conversion module converts the received optical signal into a differentially modulated signal, which is then input to the DSP chip for demodulation. The locations where polarity connection errors are prone to occur between the internal components of the PAM4 optical module are: the transmitter host segment 6 between the electrical signal receiver (in the direction of the bit error rate tester) and the DSP chip; the transmitter media segment 7 between the electro-optical conversion module and the DSP chip; the receiver media segment 8 between the photoelectric conversion module and the DSP chip; and the receiver host segment 9 between the DSP chip and the electrical signal output (in the direction of the bit error rate tester). Incorrect polarity connection between the PAM4 optical module and external devices can also occur within the bit error rate tester itself.

[0051] Based on the segmented polarity detection device provided in Embodiment 1, the detection signal generated by the bit error rate tester 1, i.e., the electrical differential signal, is split into two paths after being input to the power divider 2. One path is input to the first signal input terminal (input1) of the signal display 5 to display the code pattern of the detection signal generated by the bit error rate tester 1. The other path passes through the input terminal of the test board 3 to the electrical signal input terminal of the PAM4 optical module. After being processed by the PAM4 optical module, it is converted into an optical signal and output from the optical transmitter (TX). The optical signal output from the optical transmitter (TX) is input to the beam splitter 4 and split into two paths again. One path is input to the third signal input terminal (input3) of the signal display 5 to display the code pattern of the signal from the optical transmitter of the PAM4 optical module. The other path is input to the optical receiver (RX) of the PAM4 optical module. After being processed by the PAM4 optical module, it is converted into an electrical differential signal again and connected to the second signal input terminal (input2) of the signal display 5 through the output terminal of the test board 3. In this way, the polarity of the PAM4 optical module can be detected in three segments. If the polarity of all devices or components in the circuit is correctly connected, the code patterns of the signals input to the first signal input terminal input1, the second signal input terminal input2, and the third signal input terminal input3 will be consistent.

[0052] Based on the above detection principle, taking the detection signal code pattern output by bit error rate tester 1 as an example... Figure 3 Taking PAM4–Linearity as an example (positive differential signal), Figure 3 In the graph, the horizontal axis "Time" represents time, and the vertical axis "Amplitude (normalized)" represents the normalized amplitude of the output positive differential signal. The PAM4-Linearity coding scheme, according to the operating characteristics of the PAM4 optical module, divides the amplitude of the positive differential signal into corresponding V values. A V B V C V DFour voltage levels were used to ensure that each level was tested. The PAM4 optical module under test was inserted into the test board 3 of the segmented polarity detection device provided in Example 1. The bit error rate meter 1 was adjusted to adapt to the PAM4 optical module under test, and the code pattern was set to PAM4-Linearity. Gray encoding was disabled (normally, Gray encoding is enabled by default on the bit error rate meter). The photoelectric sampling oscilloscope was set to Patternlock mode, with a pattern length of 160UI (i.e., the length of one PAM4-Linearity pattern) and a timebase of 160UI to display a complete pattern. Under this setting, the three signals input from the first signal input terminal (input1), the second signal input terminal (input2), and the third signal input terminal (input3) were simultaneously acquired. The skew of each signal source was adjusted on the photoelectric sampling oscilloscope so that the highest level VD in the four PAM4-Linearity levels was positioned in the middle of the photoelectric sampling oscilloscope, aligning the three signal waveforms. If the bit error rate meter itself has correct polarity, the code pattern of the first signal input terminal (input1) will be aligned with the polarity of the PAM4-Linearity four-level signal. Figure 3 Consistent. Furthermore, if the polarity connection of the PAM4 optical module from the electrical signal input terminal to the optical transmitter terminal is correct, then the code patterns of the signals input to the first signal input terminal (input1) and the third signal input terminal (input3) will be consistent, specifically as follows: Figure 4 As shown, the signal with more glitches is input3. Furthermore, if the polarity connection between the optical receiver and electrical output of the PAM4 optical module is correct, then the code patterns of the signals input to the first signal input terminal (input1) and the second signal input terminal (input2) are consistent, specifically as follows: Figure 5 As shown, the signal with more spikes is input2.

[0053] More preferably, some PAM4 optical modules include a DSP chip that supports the code detection function in diagnostic monitoring, namely, polarity detection of the transmitting host segment 6 and the receiving host segment 8. Combined with the segmented polarity detection device provided in this application, more detailed polarity detection of the PAM4 optical module can be performed. If the polarity detection result of the PAM4 optical module for the transmitting host segment 6 is correct, and the code patterns of the signals input to the first signal input terminal (input1) and the third signal input terminal (input3) are consistent, then the polarity of the transmitting media segment 7 is also correct. If the polarity detection result of the PAM4 optical module for the receiving host segment 8 is correct, and the code patterns of the signals input to the first signal input terminal (input1) and the second signal input terminal (input2) are consistent, then the polarity of the receiving media segment 9 is also correct. In this way, more detailed segmented polarity detection of the PAM4 optical module can be achieved, ensuring the correct polarity of the signal transmission path of the PAM4 optical module. Based on the segmented polarity detection device provided in Embodiment 1 and the above detection principle, the corresponding error position can be deduced when a polarity error is detected, so as to adjust the polarity configuration of the relevant position in a timely manner.

[0054] It should be noted that the DSP chip in this embodiment is a physical structural component that integrates existing known programs. This embodiment does not involve any improvement of computer programs, but only provides the connection relationship between the bit error rate tester, power divider, optical splitter, signal display, test board for installing PAM4 optical module and optical module with DSP chip.

[0055] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0056] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0057] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0058] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0059] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A segmented polarity detection device for the signal transmission path of a PAM4 optical module, characterized in that, include: Bit error rate tester (1), power divider (2), optical splitter (4), signal display (5), and test board (3) for installing PAM4 optical modules; The detection signal output terminal of the bit error rate tester (1) is connected to the input terminal of the power divider (2); The first signal output terminal of the power divider (2) is connected to the first signal input terminal of the signal display (5); the second signal output terminal of the power divider (2) is connected to the input terminal of the test board (3), and the output terminal of the test board (3) is connected to the second signal input terminal of the signal display (5); The beam splitter (4) includes: an input terminal for connecting to the optical transmitter of the PAM4 optical module, a third signal output terminal for connecting to the optical receiver of the PAM4 optical module, and a fourth signal output terminal for connecting to the third signal input terminal of the signal display (5). The signal display (5) is used to display the code patterns of the signals input from the first signal input terminal, the second signal input terminal and the third signal input terminal.

2. The segmented polarity detection apparatus of claim 1, wherein, The signal display (5) is a photoelectric sampling oscilloscope; The first and second signal input terminals of the photoelectric sampling oscilloscope are electrical signal sampling terminals, and the third signal input terminal of the photoelectric sampling oscilloscope is an optical signal sampling terminal.

3. The segmented polarity detection apparatus of claim 2, wherein, The clock signal output terminal of the bit error rate tester (1) is connected to the trigger terminal of the photoelectric sampling oscilloscope.

4. The segmented polarity detection apparatus of claim 1, wherein, The error rate tester (1) has a detection signal output terminal including a TX+ output terminal and a TX- output terminal, and the power divider (2) includes a first sub-power divider (201) and a second sub-power divider (202). The TX+ output terminal is connected to the input terminal of the first sub-power divider (201), and the TX- output terminal is connected to the input terminal of the second sub-power divider (202).

5. The segmented polarity detection apparatus of claim 4, wherein, The fifth signal output terminal of the first sub-power divider (201) is connected to the first signal input terminal of the signal display (5), and the seventh signal output terminal of the second sub-power divider (202) is grounded through the first matching resistor.

6. The segmented polarity detection apparatus of claim 4, wherein, The test board (3) has two input terminals: a TX+ input terminal and a TX- input terminal. The TX+ input terminal is connected to the sixth output terminal of the first sub-power divider (201), and the TX- input terminal is connected to the eighth output terminal of the second sub-power divider (202).

7. The segmented polarity detection apparatus of claim 4, wherein, The output terminals of the test board (3) include an RX+ output terminal and an RX- output terminal; The RX+ output terminal is connected to the second signal input terminal of the signal display (5), and the RX- output terminal is grounded through the second matching resistor.

8. The segmented polarity detection apparatus of claim 5, wherein, The resistance of the first matching resistor is 50Ω.

9. The segmented polarity detection apparatus of claim 1, wherein, The test board (3) includes a connector for electrically connecting to the electrical signal input and electrical signal output terminals of the PAM4 optical module.

10. The segmented polarity detection apparatus of claim 7, wherein, The resistance of the second matching resistor is 50Ω.

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