Optical module testing device and optical module testing system

Abstract

The application relates to the field of optical module testing, and discloses an optical module testing device and an optical module testing system. The device comprises a shell, a printed circuit board, a signal transmission interface, a signal switching module and an adapter. The shell is formed with a containing cavity. The printed circuit board is arranged in the shell. The printed circuit board is provided with the signal transmission interface connected with a device under test. The printed circuit board comprises a first ground layer, a second ground layer, a first wiring layer and a second wiring layer. The signal switching module is arranged on the printed circuit board and connected with the signal transmission interface. The signal switching module has multiple signal output channels. When the signal switching module is triggered, the signal output by the device under test is output through one of the multiple signal output channels. The adapter is connected with the signal switching module. The adapter is used for connecting a testing display device. The adapter is used for outputting the signal output by the device under test through the signal switching module to the testing display device. The application solves the problem that the testing fixture needs to be disassembled and replaced multiple times when multiple modules are tested.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical module testing, in particular to an optical module testing device and an optical module testing system. BACKGROUND

[0002] With the application of optical modules in the field of high-speed data transmission, the electrical signal performance needs to meet the compliance requirements related to signal integrity (such as eye diagram, jitter, insertion loss, etc.), so consistency testing is a key link before mass production of optical modules.

[0003] The existing test fixture is applied to optical module electrical interface testing: the first kind is to adopt a circuit board design, two layers of circuit boards, optical module gold fingers, adapters and optical module housings; among them, there are 4 pairs of differential lines TX and 4 pairs of differential lines RX, which are connected to the adapters from the gold fingers; the circuit board is placed with multiple adapters for interconnection (each adapter corresponds to a signal line end connection). The second kind is to adopt an optical module gold finger plus an adapter and a cable design; the gold finger is connected to the end adapter and the cable.

[0004] The above test fixture, as the core bridge connecting the tested module and the testing instrument, has the following technical defects: frequent disassembly of the adapter and the cable can easily cause interface wear, poor contact, increase testing errors and equipment loss; and repeated disassembly and replacement are required for switching testing between multiple channel signals, which leads to prolonged testing period. SUMMARY

[0005] In view of the above shortcomings of the prior art, the purpose of the present application is to provide an optical module testing device and an optical module testing system to solve the problem of the need for multiple disassembly and replacement of connecting devices when the test fixture is used for multiple module testing.

[0006] The technical scheme of the present application is as follows:

[0007] An optical module testing device, comprising:

[0008] a housing formed with a receiving cavity;

[0009] a printed circuit board arranged in the housing, the printed circuit board being provided with a signal transmission interface for connecting a device under test; the printed circuit board comprises a first ground layer, a second ground layer, a first wiring layer and a second wiring layer, the first wiring layer and the second wiring layer being arranged between the first ground layer and the second ground layer in sequence from top to bottom, the first wiring layer and the second wiring layer being provided with shielding tapes on both sides, the shielding tapes being connected with the first ground layer and the second ground layer through reflow holes; the first wiring layer and the second wiring layer only reserve differential line wiring areas, and the remaining areas are paved with ground copper and reflow holes;

[0010] A signal switching module is arranged on the printed circuit board, the signal switching module is connected with the signal transmission interface through a signal line, the signal switching module has a plurality of signal output channels, and the signal switching module is used to output the signal output by the device under test through one of the plurality of signal output channels when triggered.

[0011] An adapter is arranged on the printed circuit board, the adapter is connected with the signal switching module, and the adapter is used to connect a test display device and output the signal output by the device under test through the signal switching module to the test display device.

[0012] Optionally, the signal switching module comprises:

[0013] A dial switch comprises a plurality of input interfaces and an output interface, the plurality of input interfaces are connected with the signal transmission interface through a signal line, the output interface is connected with the adapter through a signal line, and the dial switch is used to turn on one of the plurality of input interfaces and the output interface when triggered.

[0014] Optionally, the shell is a convex frame comprising a convex portion and a main body portion, the convex portion of the shell is used to accommodate the signal transmission interface, the main body portion of the shell is used to accommodate the printed circuit board, and an accommodation groove matched with the printed circuit board is arranged on the inner side of the main body portion of the shell.

[0015] Optionally, the light module testing device further comprises:

[0016] A shielding layer is arranged on the inner side of the main body portion of the shell, the shielding layer is arranged in matching with the printed circuit board, and the shielding layer is used to shield external electromagnetic interference signals.

[0017] Optionally, the printed circuit board comprises a first ground layer, a second ground layer, a first wiring layer and a second wiring layer, the first wiring layer and the second wiring layer are arranged between the first ground layer and the second ground layer from top to bottom in sequence, shielding tapes are arranged on both sides of the first wiring layer and the second wiring layer, and the shielding tapes are connected with the first ground layer and the second ground layer through reflow holes.

[0018] Optionally, the signal transmission interface comprises a power supply pin, a ground pin and a signal end, the power supply pin is connected with the first ground layer, the ground pin is connected with the second ground layer, and the signal end is connected with the first wiring layer and the second wiring layer.

[0019] Optionally, the printed circuit board further comprises:

[0020] A first solder pad is arranged at a middle portion of the printed circuit board, the first solder pad is connected with the first ground layer and the second ground layer through a first via, and the first solder pad is used for soldering the signal switching module;

[0021] A second solder pad is arranged at an edge of the printed circuit board, the second solder pad is connected with the first ground layer and the second ground layer through a second via, and the second solder pad is used for soldering the adapter.

[0022] Optionally, the optical module testing device further comprises:

[0023] An input differential line is arranged on the first wiring layer and the second wiring layer, and the input differential line is used for connecting the signal transmission interface and the signal switching module.

[0024] An output differential line is arranged on the first wiring layer and the second wiring layer, and the output differential line is used for connecting the signal switching module and the adapter.

[0025] Optionally, the optical module testing device is used for testing an optical module to-be-tested device of a QSFP28 or QSFP56 type.

[0026] The application further provides an optical module testing system, which comprises a to-be-tested device, a testing display device and the optical module testing device as described above, the to-be-tested device is connected with the signal transmission interface in the optical module testing device, and the testing display device is connected with the adapter in the optical module testing device.

[0027] The technical scheme of the application comprises a shell, a printed circuit board, a signal switching module and an adapter, wherein the shell is formed with a receiving cavity; the printed circuit board is provided with a signal transmission interface used for connecting a to-be-tested device; the signal switching module is connected with the signal transmission interface through a signal line, the signal switching module has a plurality of signal output channels, and the signal switching module is used for outputting a signal output by the to-be-tested device through one of the plurality of signal output channels when triggered; the adapter is connected with the signal switching module, and the adapter is used for connecting a testing display device and outputting the signal output by the to-be-tested device through the signal switching module to the testing display device. In this way, the optical module testing device of the application can connect one of a plurality of signals output by the to-be-tested device by triggering the signal switching module, without frequently disassembling the adapter and the cable, thereby reducing abrasion, avoiding signal attenuation, and shortening a testing period. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to make the technical solutions of the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only need to explain the present application, and for those skilled in the art, other drawings can be obtained from the accompanying drawings shown without any creative effort.

[0029] Figure 1 is a functional module schematic diagram of an embodiment of the optical module testing device of the present application.

[0030] Figure 2 is a structural schematic diagram of an embodiment of the optical module testing device of the present application.

[0031] Figure 3 is a structural schematic diagram of an embodiment of the first ground layer of the printed circuit board in the optical module testing device of the present application.

[0032] Figure 4 is a structural schematic diagram of an embodiment of the first wiring layer of the printed circuit board in the optical module testing device of the present application.

[0033] Figure 5 is a structural schematic diagram of another embodiment of the optical module testing device of the present application.

[0034] Legend of reference signs: 10, housing; 20, printed circuit board; 30, signal transmission interface; 40, signal switching module; 50, adapter. DETAILED DESCRIPTION

[0035] In order to make the technical solutions of the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only need to explain the present application, and for those skilled in the art, other drawings can be obtained from the accompanying drawings shown without any creative effort.

[0036] In the embodiments and the patent application scope, unless the article is specifically limited in the text, "one", "a", "said" and "the" can also include the plural form. If the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features.

[0037] It should be further understood that the use of the term "includes" in the specification of this application means that there are at least the recited features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements can also be present. Furthermore, "connected" or "coupled" as used herein can include wirelessly connected or wirelessly coupled. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0038] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as such herein.

[0039] In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection required by the present application.

[0040] With the application of optical modules in the field of high-speed data transmission, the electrical signal performance needs to meet the compliance requirements for signal integrity (such as eye diagram, jitter, insertion loss, etc.), so consistency testing is a key link before mass production of optical modules.

[0041] The existing test fixture is applied to optical module electrical interface testing: the first kind: adopting a circuit board design, two layers of circuit boards, optical module gold fingers, adapters, and optical module housings; among them, there are 4 pairs of differential lines TX and 4 pairs of differential lines RX, which are connected to the adapters from the gold fingers; the circuit board is placed with multiple adapters on both sides for interconnection (each adapter corresponds to a signal line end connection). The second kind: adopting optical module gold finger plus adapter and cable design; the gold finger is connected to the end adapter and the cable.

[0042] The above test fixture, as a core bridge connecting the tested module and the testing instrument, has the following technical defects: frequent disassembly of adapters and cables can easily cause interface wear, poor contact, increase test error and equipment loss; and repeated disassembly and replacement are required for switching test between multiple channel signals, resulting in prolonged test period.

[0043] To solve the above problems, the application provides an optical module testing device.

[0044] With reference to Figure 1 In an embodiment, the optical module testing device comprises:

[0045] A housing 10 is formed with a receiving cavity;

[0046] A printed circuit board 20 is arranged in the housing 10, and a signal transmission interface 30 for connecting a device under test is arranged on the printed circuit board 20; the printed circuit board 20 comprises a first ground layer, a second ground layer, a first wiring layer and a second wiring layer, the first wiring layer and the second wiring layer are arranged between the first ground layer and the second ground layer from top to bottom, shielding tapes are arranged on both sides of the first wiring layer and the second wiring layer, and the shielding tapes are connected with the first ground layer and the second ground layer through reflow holes; only differential line wiring areas are reserved in the first wiring layer and the second wiring layer, and the remaining areas are paved with ground copper sheets and reflow holes;

[0047] A signal switching module 40 is arranged on the printed circuit board 20, the signal switching module 40 is connected with the signal transmission interface 30 through a signal line, the signal switching module 40 has a plurality of signal output channels, and the signal switching module 40 is used for outputting the signal output by the device under test through one of the plurality of signal output channels when triggered;

[0048] An adapter 50 is arranged on the printed circuit board 20, the adapter 50 is connected with the signal switching module 40, and the adapter 50 is used for connecting a test display device; the adapter 50 is used for outputting the signal output by the device under test through the signal switching module 40 to the test display device.

[0049] In this embodiment, the shell 10 can be used to fix the positional relationship of each device on the optical module testing device, to ensure the safety and stability inside the accommodating cavity formed by the shell 10 of the optical module testing device. And the shell 10 can protect the internal components from the external environment, such as dust, moisture, chemicals and physical impact, etc. The printed circuit board 20 is a basic structure for connecting electronic components, which can be made of insulating materials (such as epoxy resin or glass fiber), and the surface is printed with conductive lines to form a circuit. The signal transmission interface 30 connected to the device under test on the printed circuit board 20 can be a gold finger, which is a metal contact point connecting the device under test and the printed circuit board 20, and the gold finger is plated with gold to ensure good conductivity and corrosion resistance. During the test, the optical module testing device sends various test signals such as electrical signals and control signals to the device under test through the gold finger; at the same time, the device under test also transmits feedback signals back to the optical module testing device through the gold finger, and the optical module testing device outputs the signals to the test display device, which can be an oscilloscope or other equipment. The user can directly see the signal test results through the test display device, so as to evaluate the performance of the optical module. The device under test can be different types of optical modules, and different types of optical modules need to be set corresponding to the connection contact points of the gold finger. In this embodiment, the printed circuit board 20 can adopt a laminated structure, specifically four layers (size 100mmx50mm), and the interlayer medium is a super low loss material, such as four layers of first ground layer, second ground layer, first wiring layer and second wiring layer, and the layer thickness is controlled as follows: the first ground layer is 0.2mm thicker than the first wiring layer, the first wiring layer is 0.4mm thicker than the second wiring layer, and the second wiring layer is 0.2mm thicker than the second ground layer. The thickness is mainly used to control the impedance, and the final design needs to be adjusted according to the actual situation. And the first ground layer and the second ground layer are fully covered with copper as the ground plane, with a copper thickness of 1oz (35μm), and the surface is treated with gold plating (gold thickness 0.05μm), to ensure the continuity of the ground; the first wiring layer and the second wiring layer only retain the differential line wiring area, and the rest of the area is covered with ground copper and reflow ground holes. The two sides of the first wiring layer and the second wiring layer are provided with shielding strips (width≥3 times line width), and the shielding strips are connected with the first ground layer and the second ground layer through reflow ground holes (spacing≤10mm, hole diameter 0.3mm) to form a "signal-ground" surrounding structure, which can reduce crosstalk; the wiring area design and reflow ground hole in this embodiment can increase the anti-interference ability.

[0050] It can be understood that, in order to solve the above problems, the signal switching module 40 is arranged in the scheme, the multiple signal output channels of the signal switching module 40 can access the multiple signals of the device under test, and by triggering the signal switching module 40, one of the multiple signal output channels is turned on, so that one signal of the device under test is accessed. Compared with the traditional scheme that a single interface corresponds to a single signal channel, the optical module testing device of the scheme does not need to frequently disassemble the adapter 50 and the cable, reduces wear and tear, avoids signal attenuation, and can also shorten the test period.

[0051] The adapter 50 is a radio frequency connector that can connect two different types of devices together. The adapter 50 can be made of copper or brass and plated with gold or nickel to improve conductivity and corrosion resistance. For example, the adapter 50 can use a high-precision SMA-K adapter with a characteristic impedance of 50Ω and a working frequency range of DC-40GHz. The interface thread is M5x0.8, and the printed circuit board 20 can be connected through reflow soldering to ensure mechanical strength.

[0052] The technical scheme of the present application comprises a housing 10, a printed circuit board 20, a signal switching module 40 and an adapter 50. The housing 10 forms a receiving cavity. The printed circuit board 20 is provided with a signal transmission interface 30 for connecting the device under test. The signal switching module 40 is connected to the signal transmission interface 30 through a signal line. The signal switching module 40 has multiple signal output channels. The signal switching module 40 is used to output the signal output by the device under test through one of the multiple signal output channels when triggered. The adapter 50 is connected to the signal switching module 40. The adapter 50 is used to connect the test display device. The adapter 50 is used to output the signal output by the device under test through the signal switching module 40 to the test display device. In this way, the optical module testing device of the scheme can access one of the multiple signals output by the device under test by triggering the signal switching module 40, without frequently disassembling the adapter 50 and the cable, reducing wear and tear, avoiding signal attenuation, and also shortening the test period.

[0053] Reference Figure 2 In an embodiment, the signal switching module 40 comprises:

[0054] The paddle switch comprises multiple input interfaces and an output interface. The multiple input interfaces are connected to the signal transmission interface 30 through a signal line. The output interface is connected to the adapter 50 through a signal line. The paddle switch is used to turn on one of the multiple input interfaces and the output interface when triggered.

[0055] In this embodiment, the signal switching module 40 can be a dial switch. For example, the dial switch can be a 4-channel mechanical dial switch, which includes 4 groups of input interfaces (corresponding to 4 pairs of TX / RX differential lines) and 1 group of output interfaces (corresponding to 1 pair of output differential lines). The internal contacts of the switch are gold plated (gold thickness 0.5 μm), and the contact resistance is ≤50 mΩ. The specific number of channels can be set according to actual conditions and user requirements. The switching mechanism is to manually dial the switch gear (for example, 0-3 gears), to realize the switching of 4 pairs of input signals: when dialing to "0 gear", the first pair of differential lines is connected to the output line; when dialing to "1 gear", the second pair of differential lines is connected to the output line, and so on, to ensure that only one pair of differential lines is connected to the adapter 50 through the output line each time. In this way, the present scheme shortens the 4-pair signal channel test of a device from 10 minutes in the traditional scheme to 2 minutes. The mechanical switching mechanism does not need to repeatedly disassemble the adapter 50 and the cable, and the switching time of a single signal channel is shortened from 2 minutes in the traditional scheme to 5 seconds. In this embodiment, the dial switch is used to better switch the high-speed differential electrical signal (25 Gbps and above). In specific applications, other devices with similar functions to the dial switch can also be selected according to actual conditions and user requirements.

[0056] Referring to Figure 5 In another embodiment, a jumper cap scheme can be used to replace the dial switch scheme. The switching test is performed by manually changing the jumper cap connected to each signal channel, without frequently disassembling the cable and the adapter 50. In this way, the effect of switching multiple signal channels can also be achieved.

[0057] Referring to Figure 2 In an embodiment, the shell 10 is a convex frame, which includes a convex portion and a main body portion. The convex portion of the shell 10 is used to accommodate the signal transmission interface 30, and the main body portion of the shell 10 is used to accommodate the printed circuit board 20. The inner side of the main body portion of the shell 10 is provided with a clamping groove matched with the printed circuit board 20.

[0058] In this embodiment, the shell 10 is designed as a convex frame to accommodate the printed circuit board 20 and the signal transmission interface 30. Because the signal transmission interface 30 is arranged on the printed circuit board 20, the overall structure is a convex structure, and the shell 10 is designed as a convex frame to accommodate the printed circuit board 20. The specific size of the frame can be designed according to the size of the signal transmission interface 30 and the printed circuit board 20. The shell 10 can be made of aluminum alloy with a thickness of 1.2 mm, and has a structure of "convex frame + top cover". The inner side of the main body portion of the shell 10 is provided with a clamping groove (tolerance ±0.05 mm) matched with the edge of the printed circuit board 20. The shell 10 is fixed to the printed circuit board 20 by 4 M2 screws. The arrangement of the M2 screws can be referred to Figure 2The top cover plate is a card slot above the entire signal transmission interface 30. The thickness of the shell 10 can also be set according to actual conditions and user needs. Figure 2 The card slot provided on the inner side of the main body of the shell 10 is matched with the printed circuit board 20.

[0059] It can be understood that high-speed signals (data transmission rate ≥ 25 Gbps) are susceptible to external electromagnetic interference and crosstalk during transmission, resulting in test result deviation.

[0060] Therefore, in an embodiment, the optical module test device further comprises:

[0061] A shielding layer is provided on the inner side of the main body of the shell 10. The shielding layer is matched with the printed circuit board 20. The shielding layer is used to shield external electromagnetic interference signals.

[0062] In this embodiment, the shielding layer is a 3 μm thick nickel-gold layer electroplated on the inner side of the main body of the shell 10 frame. The shielding layer is matched with the shape of the printed circuit board 20. The shielding layer can wrap the printed circuit board 20 to form an electromagnetic shielding cavity (shielding effectiveness ≥ 60 dB @ 1-10 GHz), which can isolate the influence of external electromagnetic interference on high-speed signals. The specific thickness can also be set according to actual conditions and user needs. In addition to the nickel-gold layer, the shielding layer can also be made of other materials that meet the shielding performance. Compared with the traditional “separated fixing + independent shielding” design, the shell only plays a fixing support role, while the mechanical support and electromagnetic shielding functions of the shell 10 and the printed circuit board 20 are integrated in this embodiment. The nickel-gold layer is electroplated on the inner side of the shell 10 to form a closed shielding cavity, which can isolate the influence of external electromagnetic interference on high-speed signals and solve the problem of result deviation caused by noise interference in the test environment.

[0063] Further, in an embodiment, the signal transmission interface 30 comprises a power pin, a ground pin and a signal end. The power pin is connected with the first ground layer, the ground pin is connected with the second ground layer, and the signal end is connected with the first wiring layer and the second wiring layer.

[0064] The printed circuit board 20 further comprises:

[0065] A first pad is provided in the middle of the printed circuit board 20. The first pad is connected with the first ground layer and the second ground layer through a first via. The first pad is used to weld the signal switching module 40.

[0066] A second pad is provided at the edge of the printed circuit board 20. The second pad is connected with the first ground layer and the second ground layer through a second via. The second pad is used to weld the adapter 50.

[0067] In this embodiment, the signal transmission interface 30 is taken as an example of a gold finger. In this embodiment, a QSFP standard gold finger (in accordance with the SFF-8636 specification) is used, which has a total of 38 pins. The power pins and ground pins are directly connected to the first ground layer and the second ground layer, respectively, and the signal pins are connected to the differential lines of the first wiring layer and the second wiring layer, respectively. Eight groups of 2.54 mm pitch pads (a total of 16 pins) can be reserved in the middle of the printed circuit board 20. The printed circuit board 20 is designed with positive and negative symmetry of the first ground layer and the second ground layer, and is used to solder the signal switching module 40. The first pads are connected to the first ground layer and the second ground layer through first vias (aperture 0.3 mm) to ensure reliable grounding. Two groups of 50Ω pads (center pin diameter 0.8 mm, ground ring diameter 3 mm) can be reserved at the edge of the printed circuit board 20. The printed circuit board 20 is designed with positive and negative symmetry of the first ground layer and the second ground layer. The second pads are connected to the first ground layer and the second ground layer through second vias to reduce impedance discontinuity. The arrangement of the signal switching module 40 and the adapter 50 on the first ground layer can be specifically referred to Figure 3 .

[0068] Referring to Figure 2 In an embodiment, the optical module testing device further comprises:

[0069] Input differential lines arranged on the first wiring layer and the second wiring layer, the input differential lines being used to connect the signal transmission interface 30 and the signal switching module 40;

[0070] Output differential lines arranged on the first wiring layer and the second wiring layer, the output differential lines being used to connect the signal switching module 40 and the adapter 50.

[0071] In this embodiment, the input differential lines can be composed of 4 pairs of TX differential lines and 4 pairs of RX differential lines, each pair of differential lines having an impedance of 100Ω±10% and a line length error of ≤5 mm. The TX differential lines are arranged on the first wiring layer of the printed circuit board 20, are led out from the signal pins of the gold finger, and are all routed on the first wiring layer and connected to the first pads on the first ground layer. The arrangement of the TX differential lines can be specifically referred to Figure 4TX lane0, TX lane1, TX lane2, and TX lane3 represent 4 pairs of TX differential lines respectively; RX differential lines are arranged on the second wiring layer of the printed circuit board 20, and after being led out from the signal pins of the gold finger, all are wired on the second wiring layer and connected to the second solder pad on the second ground layer. The arrangement of the RX differential lines can refer to the arrangement of the TX differential lines. It should be noted that in the embodiment, the RX signal differential lines can be designed in mirror image of the TX (the TX is arranged on the first ground layer and the first wiring layer, and the RX is arranged on the second wiring layer and the second ground layer), and two DIP switches (4 inputs and 1 output) and 4 adapters are needed, which are symmetrically placed on the first ground layer and the second ground layer. The output differential line is led out from the first solder pad as 1 pair of differential lines, and is mixedly wired on the first wiring layer and the second wiring layer (according to the selected signal channel of the switch), and finally connected to the second solder pad. The length of the wire is controlled within 50 mm (to reduce high-frequency loss). For details, please refer to Figure 4 wherein lane represents the output differential line. In the embodiment, the impedance of the differential line is controlled to be 100Ω±10% (the line width and line spacing are calibrated through simulation / test verification: line width 0.25 mm, line spacing 0.3 mm), which can reduce signal reflection.

[0072] Further, in another embodiment, the printed circuit board can adopt a two-layer design for testing the TX signal. The two-layer design is that only the TX signal is designed to be wired on the first layer, and a DIP switch (4 inputs and 1 output) and 2 adapters are arranged on the first layer. For details, please refer to Figure 2 The four-layer design of the printed circuit board in the above embodiment is used for testing the TX signal and the RX signal, which is a compliance test of the Ethernet protocol for the RX signal. It mainly tests the error rate of the loopback, while the compliance test of the TX mainly tests the eye diagram jitter and other requirements. The test display devices used for the two are different. The oscilloscope is used for the TX signal, and the error code instrument is used for the RX signal. And the test by using the oscilloscope or the error code instrument is carried out separately. The four-layer design of the printed circuit board is that the TX signal and the RX signal are independently connected to their own DIP switch and adapter, which is better for signal integrity. The two-layer design of the printed circuit board is simpler in structure and higher in test efficiency. The corresponding printed circuit board can be designed according to the actual situation and user demand.

[0073] In an embodiment, the optical module test device is used for testing an optical module to-be-tested device of a model of QSFP28 or QSFP56.

[0074] In this embodiment, the optical modules under test, specifically the QSFP28 and QSFP56 models, are four-channel optical modules, characterized by their small size and high density, making them suitable for high-speed data transmission applications. The optical module testing device in this solution is a verification fixture for the electrical signals of QSFP28 or QSFP56 models. Other models, such as SFP / SFP+ / XFP / QSFPDD, differ mainly in the pin design of the gold fingers; therefore, this optical module testing device is not a universal testing device for all models. This is because the number of pins on the gold fingers differs—for example, QSFP28 has 38 pins, while SFP+ has only 20—and the structural dimensions also differ. It should be noted that the differential line impedance design requirements differ for different interfaces. In this embodiment, the electrical signals of the QSFP28 optical module are generally controlled between 90 and 100 ohms impedance.

[0075] This invention also proposes an optical module testing system.

[0076] In one embodiment, the optical module testing system includes a device under test (DUT), a test display device, and an optical module testing apparatus as described above. The DUT is connected to the signal transmission interface 30 in the optical module testing apparatus, and the test display device is connected to the adapter 50 in the optical module testing apparatus. In this embodiment, the overall testing process of the optical module testing system of the present invention is as follows: First, the DUT is powered on and enters the compliance test mode, sending the corresponding pseudo-random code signal according to the IEEE (Institute of Electrical and Electronics Engineers) 802.3 protocol. The signal transmission interface 30 of the optical module testing apparatus is inserted into the DUT, and the toggle switch is set to position 0, corresponding to the first signal channel. The adapter 50 of the optical module testing apparatus is connected to the test display device via a cable. The test display device can be an oscilloscope, etc., so that testing can be performed on the oscilloscope and a compliance report can be output. Then, the toggle switch is switched to position 1, corresponding to the second signal channel, and so on, until the testing of all four signal channels of one DUT is completed. The optical module testing device is then plugged in and unplugged to test the next device under test (DUT), and so on. This allows multiple DUTs to be tested. Furthermore, when testing a single DUT, it is not necessary to disassemble multiple signal channels, reducing interface wear and shortening the testing time for a single DUT.

[0077] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An optical module testing device characterized by comprising: The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device.

2. The optical module testing apparatus according to claim 1, wherein The application relates to an optical module testing device. The application relates to an optical module testing device.

3. The optical module testing apparatus according to claim 1, wherein The application relates to an optical module testing device.

4. The optical module testing apparatus according to claim 3, wherein The application relates to an optical module testing device. The application relates to an optical module testing device.

5. The optical module testing apparatus according to claim 1, wherein The application relates to an optical module testing device.

6. The optical module testing apparatus according to claim 1, wherein The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device.

7. The optical module testing apparatus according to claim 1, wherein The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. The application relates to an optical module testing device. 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The application relates to an optical module testing An input differential line is arranged on the first wiring layer and the second wiring layer, and is used to connect the signal transmission interface and the signal switching module. An output differential line is arranged on the first wiring layer and the second wiring layer, and is used to connect the signal switching module and the adapter.

8. The optical module testing apparatus according to claim 1, wherein The optical module testing device is used for testing a to-be-tested optical module device of a QSFP28 or QSFP56 type.

9. An optical module testing system, characterized by, The optical module testing device comprises a to-be-tested device, a testing display device and an optical module testing device as claimed in any one of claims 1-8, the to-be-tested device is connected with the signal transmission interface in the optical module testing device, and the testing display device is connected with the adapter in the optical module testing device.

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