Printed circuit board and optical module

Abstract

The utility model provides a printed circuit board and an optical module. The circuit board comprises a first surface layer and a second surface layer which are opposite, and a first signal layer and a second signal layer which are laminated between the first surface layer and the second surface layer; one end of the circuit board is provided with an electric connection part, and the electric connection part comprises a second transmitting end golden finger and a second receiving end golden finger which are located on the first surface layer, and a first transmitting end golden finger and a first receiving end golden finger which are located on the second surface layer; the first surface layer is provided with a signal processor, a plurality of pairs of receiving differential lines electrically connected with the first receiving end golden finger, the second receiving end golden finger and the signal processor are arranged on the first signal layer, and a plurality of pairs of transmitting differential lines electrically connected with the first transmitting end golden finger, the second transmitting end golden finger and the signal processor are arranged on the second signal layer. Therefore, transmitting end signals and receiving end signals are isolated. According to the invention, the problems of dense PCB high-speed signal lines and wiring caused by the increase of optical module signal channels can be solved, and the high-frequency performance and the anti-interference capability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical communication technology, in particular to a printed circuit board and an optical module. BACKGROUND

[0002] With the explosive growth of information, the demand for data centers is increasing, and the requirements for transmission rate and bandwidth are also increasing. In response to this trend, optical module manufacturers have developed new optical modules with a transmission rate of 1.6Tbps, using a completely new packaging form that can support faster transmission rates and longer transmission distances, providing more efficient and reliable solutions for data center applications.

[0003] However, as the speed of optical modules increases, the high-speed signal channels also increase accordingly, but the size of the optical module is limited by standards and cannot be increased synchronously, and may even be required to be smaller and smaller. The high-speed signal channels of the optical module become increasingly dense and complex, and how to achieve reliable signal transmission under such conditions has become one of the technical problems that optical module manufacturers need to solve. In addition, the wiring, signal integrity and electromagnetic scattering of high-speed signal channels also require more delicate design and optimization to ensure the stable operation and reliability of the optical module. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a printed circuit board and an optical module to solve the problem of how to achieve high-density wiring and signal integrity, reduce electromagnetic interference under the conditions of high-speed transmission, small size and dense signal channels of the optical module, to ensure the stable operation and reliability of the optical module.

[0005] In a first aspect, the present application provides a printed circuit board, comprising a first surface layer and a second surface layer opposite to each other, and a plurality of inner layers laminated between the first surface layer and the second surface layer, the plurality of inner layers comprising a first signal layer and a second signal layer, and the first surface layer is configured with at least one signal processor;

[0006] One end of the printed circuit board is provided with an electrical connection part, the electrical connection part comprises a second transmitting end gold finger and a second receiving end gold finger located on the first surface layer, and a first transmitting end gold finger and a first receiving end gold finger located on the second surface layer, all the gold fingers extend along the length direction of the printed circuit board;

[0007] The first signal layer is provided with a plurality of pairs of receiving differential lines, one end of each pair of receiving differential lines is electrically connected to the signal processor, and the other end of a part of the receiving differential lines is electrically connected to the first receiving end gold finger, and the other end of the other part is electrically connected to the second receiving end gold finger;

[0008] The second signal layer is provided with a plurality of pairs of transmitting differential lines, one end of each of the plurality of pairs of transmitting differential lines is electrically connected to the signal processor, and the other end of a part of the plurality of pairs of transmitting differential lines is electrically connected to the first transmitting end gold finger, and the other end of another part is electrically connected to the second transmitting end gold finger.

[0009] In a second aspect, the application further provides an optical module comprising the printed circuit board according to any one of the first aspect.

[0010] The plurality of transmitting differential lines of the printed circuit board are all from the same inner layer trace, the plurality of receiving differential lines are all from the same inner layer trace, and the receiving differential lines and the transmitting differential lines are located in different layers, so that the transmitting signal lines and the receiving signal lines are isolated, and mutual interference between the transmitting end and the receiving end can be avoided; in addition, through reasonable arrangement of the signal lines, the problems of dense high-speed signal channels, complex wiring, and discontinuous impedance of the printed circuit board caused by an increasing number of signal channels in the optical module can be effectively solved, so that the high-frequency performance and the anti-interference performance of the printed circuit board are effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0012] Figure 1 is a schematic diagram of an optical module;

[0013] Figure 2 is a layout schematic diagram of a first surface layer of the printed circuit board provided by the embodiments of the present application;

[0014] Figure 3 is a partial three-dimensional schematic diagram of the printed circuit board provided by the embodiments of the present application;

[0015] Figure 4 is a schematic diagram of the transmitting differential lines of the printed circuit board provided by the embodiments of the present application;

[0016] Figure 5 is a schematic diagram of the receiving differential lines of the printed circuit board provided by the embodiments of the present application;

[0017] Figure 6 is a wiring diagram of the first signal layer provided by the embodiments of the present application;

[0018] Figure 7 is a wiring diagram of the second signal layer provided by the embodiments of the present application;

[0019] Figure 8 is a first side transmitting differential line via connection schematic diagram provided by the embodiment of the present application

[0020] Figure 9 is a second side receiving differential line via connection schematic diagram provided by the embodiment of the present application.

[0021] Figure number explanation:

[0022] Optical module 100: housing 101;

[0023] Printed circuit board 1: first surface layer 11, second surface layer 12, first side 13, second side 14, a plurality of inner layers 15, first signal layer 16, second signal layer 17, conductive via 18;

[0024] Differential line 2:

[0025] Receiving differential line 21: first group of receiving differential lines 211, first receiving connection section 2111, first receiving transmission section 2112; second group of receiving differential lines 212, second receiving connection section 2121, second receiving transmission section 2122;

[0026] Transmitting differential line 22: first group of transmitting differential lines 221, first transmitting connection section 2211, first transmitting transmission section 2212; second group of transmitting differential lines 222, second transmitting connection section 2221, second transmitting transmission section 2222;

[0027] Electric connection part 3: first transmitting end gold finger 30, second transmitting end gold finger 31, first receiving end gold finger 32, second receiving end gold finger 33, power supply gold finger 34, first row of gold fingers 35, second row of gold fingers 36, end part 37, differential signal gold finger 38, ground gold finger 39;

[0028] Signal processor 4, receiving capacitor 41, transmitting capacitor 42. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application more clear, the technical scheme of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] The terms "first", "second", and the like in the description and in the claims of the present application and above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged, where appropriate, so that the embodiments described herein can be carried out in other than the order depicted or described herein.

[0031] The optical module is a key device for optical communication, which is used to realize the transmission and reception of optical signals and the conversion between optical signals and electrical signals in an optical fiber communication system. As shown in Figure 1 and 2 The optical module 100 generally includes a housing 101, a printed circuit board 1 and an optical assembly (not shown in the figure), the printed circuit board 1 and the optical assembly 102 are arranged in the housing, and the printed circuit board 1 has an electrical connection part 3 exposed outside the housing 101, which is used to electrically connect with external devices such as switches or servers. In a pluggable optical module, the electrical connection part 3 of the printed circuit board 1 is generally a gold finger, which can be connected with external devices in a plug-in manner. The optical assembly 102 includes at least one transmitting part and one receiving part. In the transmitting part, after the electrical signal is processed by the internal drive chip, the light source (such as a laser or an LED) is driven to emit a modulated light signal or a modulator is driven to modulate the electrical signal onto a light beam to form an optical signal output. The optical signal is transmitted to the receiving end of the remote optical module 100 through an optical fiber. In the receiving part, the received optical signal is converted into an electrical signal by an optical detector. The receiving part also includes a transimpedance amplifier, a preamplifier and the like to enhance the strength of the electrical signal, and the signal processor 4 is used for demodulation and processing to recover the original data signal.

[0032] In the optical module 100, the signal processor 4, the drive chip, the amplifier, the capacitor and other functional components of the transceiver part are arranged on the printed circuit board 1, and the paths and layouts required for signal transmission, power control and other circuit functions are provided. Therefore, the printed circuit board 1 is crucial in the operation of the optical module 100, which ensures the normal connection and signal transmission between various components, especially the transmission line of high-speed signals, which has an important influence on the performance and reliability of the entire optical module.

[0033] In order to solve the problems of the optical module under the conditions of high-speed transmission, small size and dense signal channels, the present application provides a printed circuit board and an optical module, which respectively arrange transmitting differential lines and receiving differential lines in different inner layers of the printed circuit board, so as to realize effective isolation of the signal lines and avoid mutual interference between the transmitting end and the receiving end. In addition, the reasonable arrangement of the signal lines solves the problems of dense high-speed signal channels, complex wiring and impedance discontinuity, etc., improves the high-frequency performance and anti-interference ability of the circuit board, and ensures the stable operation and reliability of the optical module under the conditions of high-speed transmission, small size and dense signal channels.

[0034] The following will be described in combination with Figures 1-9The printed circuit board and optical module of the present application are described.

[0035] Exemplarily, referring to Figure 1 , the optical module 100 and the printed circuit board 1 have mutually perpendicular length direction X, width direction Y and thickness direction Z, the optical module 100 can be inserted or pulled out of external equipment such as a switch or a server along the length direction X. Wherein, referring to Figures 2-5 , in one embodiment of the present application, the printed circuit board 1 includes opposite first surface layer 11 and second surface layer 12, and a plurality of inner layers 15 laminated between the first surface layer 11 and the second surface layer 12, the plurality of inner layers 15 includes first signal layer 16 and second signal layer 17, the first surface layer 11 is configured with at least one signal processor 4, which is responsible for processing and optimizing the transmit end electrical signal and the receive end electrical signal received by it.

[0036] One end of the printed circuit board 1 is provided with an electrical connection part 3, the electrical connection part 3 includes a second transmit end gold finger 31 and a second receive end gold finger 33 located in the first surface layer 11, and a first transmit end gold finger 30 and a first receive end gold finger 32 located in the second surface layer 12, all the gold fingers extend along the length direction X of the printed circuit board 1, consistent with the direction of inserting and pulling out the optical module 100.

[0037] The first signal layer 16 of the printed circuit board 1 is provided with a plurality of pairs of receive differential lines 21, one end of the plurality of pairs of receive differential lines 21 is electrically connected to the signal processor 4, the other end of a part of the plurality of pairs of receive differential lines 21 is electrically connected to the first receive end gold finger 32, and the other part is electrically connected to the second receive end gold finger 33. The receive differential line 21 is used for transmitting high-speed signals between the signal processor and the receive end gold finger.

[0038] The second signal layer 17 is provided with a plurality of pairs of transmit differential lines 22, one end of the plurality of pairs of transmit differential lines 22 is electrically connected to the signal processor 4, the other end of a part of the plurality of pairs of transmit differential lines 22 is electrically connected to the first transmit end gold finger 30, and the other part is electrically connected to the second transmit end gold finger 31. The transmit differential line 22 is used for transmitting high-speed signals between the transmit end gold finger and the signal processor. That is, the receive differential line 21 for transmitting receive signals between the electrical connection part 3 and the signal processor 4 is located in the first signal layer 16, and the transmit differential line 22 for transmitting transmit signals is located in the second signal layer 17.

[0039] During the whole working process, the differential transmission mode can suppress common mode noise and interference, improve the transmission quality, transmission speed and stability of the signal, and has greater bandwidth capacity and higher transmission rate. Moreover, the receiving differential line and the transmitting differential line are respectively located in different inner layers of the printed circuit board, realizing effective isolation of the signal line and avoiding mutual interference of the transmitting end and the receiving end. This design enables the printed circuit board 1 to realize high-speed, stable and anti-interference signal reception and transmission under the conditions of high-speed transmission, small size and dense signal channels, thereby ensuring the stable operation and reliability of the optical module.

[0040] As shown in Figures 2 to 7 In this embodiment, the electrical connection part is arranged to be consistent with the electrical interface required by the standard of the pluggable optical module. The electrical connection part 3 also includes power gold fingers 34 located in the first surface layer 11 and the second surface layer 12 respectively. In the width direction Y of the printed circuit board 1, the power gold fingers 34 are located at the middle position of the electrical connection part 3, and the printed circuit board 1 is divided into a first side 13 and a second side 14 by the power gold fingers 34 and their extension lines; the first transmitting end gold finger 30 and the second transmitting end gold finger 31 are located on the first side 13, and the first receiving end gold finger 32 and the second receiving end gold finger 33 are located on the second side 14.

[0041] Among them, the power gold fingers 34 are located at the middle position of the electrical connection part 3, and divide the printed circuit board 1 into a first side 13 and a second side 14 in the width direction of the printed circuit board 1. This layout design makes the transmitting end gold fingers (the first transmitting end gold finger 30 and the second transmitting end gold finger 31) and the receiving end gold fingers (the first receiving end gold finger 32 and the second receiving end gold finger 33) located on different sides of the printed circuit board 1, which helps to optimize physical isolation and signal management, ensures the centralization of power supply and clear zoning of signal transmission, thereby improving the overall performance and reliability of the printed circuit board 1.

[0042] In this embodiment, the first transmitting end gold finger 30, the second transmitting end gold finger 31, the first receiving end gold finger 32 and the second receiving end gold finger 33 each include a plurality of groups of differential signal gold fingers arranged along the width direction Y, and each group of differential signal gold fingers 38 is provided with a grounding gold finger 39 on both sides. The grounding gold fingers 39 are arranged on both sides of each group of differential signal gold fingers, forming an electromagnetic shielding structure on both sides of each group of differential signal gold fingers, which helps to reduce crosstalk between each high-speed signal channel, while isolating the high-speed signal from external interference, to ensure the quality of signal transmission.

[0043] As shown in Figures 2 to 7As shown, taking a sixteen-channel high-speed optical module as an example, the first signal layer 16 of the printed circuit board is provided with 16 pairs of receiving differential lines 21, of which 8 pairs of receiving differential lines 21 are electrically connected to the first receiving end gold fingers 32, and the other 8 pairs of receiving differential lines 21 are electrically connected to the second receiving end gold fingers 33. The second signal layer 17 is provided with 16 pairs of transmitting differential lines, of which 8 pairs of transmitting differential lines 22 are electrically connected to the first transmitting end gold fingers 30, and the other 8 pairs of transmitting differential lines 22 are electrically connected to the second transmitting end gold fingers 31. Of course, in other embodiments, an eight-channel or thirty-two-channel high-speed optical module can also correspond to the number of receiving differential lines and transmitting differential lines of the channels.

[0044] In this embodiment, the plurality of pairs of receiving differential lines 21 include a first group of receiving differential lines 211 (such as RX1-8) and a second group of receiving differential lines 212 (such as RX9-16).

[0045] Please refer to Figures 6-9 In the first group of receiving differential lines 211, each pair of receiving differential lines includes a first receiving connection segment 2111 and a first receiving transmission segment 2112. The first receiving connection segment 2111 is located on the second signal layer 17, and the first receiving transmission segment 2112 is located on the first signal layer 16. One end of the first receiving connection segment 2111 projects into the corresponding first receiving end gold finger 32 on the second surface layer 12, and is electrically connected to the corresponding first receiving end gold finger 32 through the conductive via 18. The other end of the first receiving connection segment 2111 is electrically connected to the first receiving transmission segment 2112 through the conductive via 18. For details, please refer to Figure 9 The first group of receiving differential lines 211 is connected between the first signal layer 16 and the second signal layer 17 through the conductive via 18.

[0046] In the second group of receiving differential lines 212, each pair of receiving differential lines includes a second receiving connection segment 2121 and a second receiving transmission segment 2122, both of which are located on the first signal layer 16. One end of the second receiving connection segment 2121 projects into the corresponding second receiving end gold finger 33 on the first surface layer 11, and is electrically connected to the corresponding second receiving end gold finger 33 through the conductive via 18. The other end of the second receiving connection segment 2121 is connected to the second receiving transmission segment 2122.

[0047] The receiving end gold fingers of this embodiment meet the standard design requirements of the optical module, are respectively located on different surface layers, and uniformly arrange the main signal transmission segments of all receiving differential lines on the first signal layer. Then, each pair of receiving differential lines is connected to the corresponding receiving end gold finger located on different surface layers through the receiving connection segment and the conductive via, which optimizes the wiring design of the receiving differential lines, enables the optical module under the standard size limit to integrate more signal channels, has better impedance characteristics, and improves the high-frequency performance.

[0048] Specifically, as shown in Figures 2 to 7 the first receiving connection segment 2111 and the second receiving connection segment 2121 fall within the power supply gold fingers 34 and the second side 14. One end of the first receiving transmission segment 2112 is electrically connected to the signal processor 4 at the first side 13 and extends along the length direction within the first side 13, and the other end extends obliquely from the first side 13 to the second side 14 to electrically connect the first receiving connection segment 2111. One end of the second receiving transmission segment 2122 is electrically connected to the signal processor 4 at the second side 14 and connects the second receiving connection segment 2121 within the second side 14.

[0049] On the printed circuit board, the first receiving end gold fingers 32 and the second receiving end gold fingers 33 each include a first row of gold fingers 35 and a second row of gold fingers 36 arranged along the length direction, wherein the second row of gold fingers 36 is relatively close to the signal processor 4 and is insulated and spaced apart from the first row of gold fingers 35. In the arrangement order from the second side 14 towards the first side 13, i.e. as viewed from the second side 14 to the first side 13, the odd pairs of differential lines (e.g. RX1, RX3, RX5, RX7) of the first group of receiving differential lines 211 (e.g. RX1-8) are electrically connected to the second row of gold fingers 36 of the first receiving end gold fingers 32, and the even pairs of differential lines (e.g. RX2, RX4, RX6, RX8) are electrically connected to the first row of gold fingers 35 of the first receiving end gold fingers 32, while the odd pairs of differential lines (e.g. RX9, RX11, RX13, RX15) of the second group of receiving differential lines 212 (e.g. RX9-16) are electrically connected to the first row of gold fingers 35 of the second receiving end gold fingers 33, and the even pairs of differential lines (e.g. RX10, RX12, RX14, RX16) are electrically connected to the second row of gold fingers 36 of the second receiving end gold fingers 33. The same group of receiving differential lines are connected to the two rows of first receiving end gold fingers 32 and second receiving end gold fingers 33 in an odd-even staggered manner according to the arrangement order, which reduces the crosstalk between adjacent receiving differential lines and further optimizes the high-frequency performance.

[0050] Similarly, as shown in Figures 6 to 9 in this embodiment, the multiple pairs of transmitting differential lines 22 include a first group of transmitting differential lines 221 (e.g. TX1-8) and a second group of transmitting differential lines 222 (e.g. TX9-16).

[0051] In the first group of transmission differential lines 221, each pair of transmission differential lines comprises a first transmission connecting segment 2211 and a first transmission transmission segment 2212, both of which are located in the second signal layer 17. One end of the first transmission connecting segment 2211 falls within the corresponding first transmission end gold finger 30 in the projection of the second surface layer 12, and is electrically connected to the corresponding first transmission end gold finger 30 through the conductive via 18, and the other end of the first transmission connecting segment 2211 is connected to the first transmission transmission segment 2212.

[0052] In the second group of transmission differential lines 222, each pair of transmission differential lines comprises a second transmission connecting segment 2221 and a second transmission transmission segment 2222, the second transmission connecting segment 2221 is located in the first signal layer 16, and the second transmission transmission segment 2222 is located in the second signal layer 17; one end of the second transmission connecting segment 2221 falls within the corresponding second transmission end gold finger 31 in the projection of the first surface layer 11, and is electrically connected to the corresponding second transmission end gold finger 31 through the conductive via 18, and the other end of the second transmission connecting segment 2221 is electrically connected to the second transmission transmission segment 2222 through the conductive via 18. For details, please refer to Figure 8 The second group of transmission differential lines 222 is connected between the first signal layer 16 and the second signal layer 17 through the conductive via 18.

[0053] The transmission end gold fingers of this embodiment meet the standard design requirements of the optical module, are located in different surface layers, and all the main signal transmission segments of the transmission differential lines are evenly arranged in the second signal layer. Each pair of transmission differential lines is connected to the corresponding transmission end gold finger located in different surface layers through the transmission connecting segment and the conductive via. The wiring design of the transmission differential lines is optimized, so that the optical module with standard size limitation can integrate more signal channels, while having better impedance characteristics and improving high-frequency performance.

[0054] Specifically, as shown in Figures 2 to 7 The projections of the first transmission connecting segment 2211 and the second transmission connecting segment 2221 in the second surface layer 12 fall within the power gold finger 34 and the first side 13; one end of the first transmission transmission segment 2212 is electrically connected to the signal processor 4 in the first side 13, and the other end is connected to the first transmission connecting segment 2211 in the first side 13; one end of the second transmission transmission segment 2222 is electrically connected to the signal processor 4 in the second side 14, and the other end extends along the length direction in the second side 14, and the other end extends from the second side 14 to the first side 13 to electrically connect the second transmission connecting segment 2221.

[0055] On the printed circuit board, the first transmitter gold finger 30 and the second transmitter gold finger 31 both include a first row of gold fingers 35 and a second row of gold fingers 36 arranged along the length direction, wherein the second row of gold fingers 36 is relatively close to the signal processor 4 and is insulated from the first row of gold fingers 35. In the width direction, in the arrangement from the first side 13 to the second side 14, that is, looking from the first side 13 to the second side 14, the odd-numbered pairs of differential lines (such as TX1, TX3, TX5, TX7) of the first group of transmitting differential lines 221 (such as TX1-8) are electrically connected to the first row of gold fingers 35 of the first transmitting end gold fingers 30, and the even-numbered pairs of differential lines (such as TX2, TX3, TX6, TX8) are electrically connected to the second row of gold fingers 36 of the first transmitting end gold fingers 30. The odd-numbered pairs of differential lines (such as TX9, TX11, TX13, TX15) of the second group of transmitting differential lines 222 (such as TX9-16) are electrically connected to the second row of gold fingers 36 of the second transmitting end gold fingers 31, and the even-numbered pairs of differential lines (such as TX10, TX12, TX14, TX16) are electrically connected to the first row of gold fingers 35 of the second transmitting end gold fingers 31. Connecting the first transmitter gold finger 30 and the second transmitter gold finger 31 to the same set of transmit differential lines in an alternating odd and even order reduces crosstalk between adjacent receive differential lines and further optimizes high-frequency performance.

[0056] It is evident that the layout and connection method of the receiving differential lines, transmitting differential lines, receiver gold fingers, and transmitter gold fingers helps reduce the problem of differential line impedance discontinuities and optimizes the impedance characteristics of high-speed signal lines. Furthermore, the odd and even pairs of the receiving differential lines are connected to different rows of receiver gold fingers, and the odd and even pairs of the transmitting differential lines are connected to different rows of transmitter gold fingers. This cross-connection method helps reduce signal interference and improve signal transmission clarity, further enhancing high-frequency performance.

[0057] In some embodiments, such as Figures 6 to 9 As shown, conductive vias 18 are connected to the ends 37 of the first receiving gold finger 32, the second receiving gold finger 33, the first transmitting gold finger 30, and / or the second transmitting gold finger 31 that are relatively close to the signal processor 4. That is, each gold finger end is connected to the inner layer's receiving differential line and transmitting differential line via conductive vias, eliminating the need for additional microstrip lines on the surface layer. This design avoids impedance discontinuities at the gold finger pads, microstrip lines, and conductive vias, reducing the number of reflection points on the signal link, thereby further improving the high-frequency performance of the printed circuit board and reducing electric field interference.

[0058] In some embodiments, the printed circuit board 1 further comprises a ground layer (not shown in the figures) between the first signal layer 16 and the second signal layer 17 for isolating the transmitting differential lines and the receiving differential lines, further reducing the crosstalk between the transmitting end and the receiving end. Moreover, the ground layer can also serve as a shielding layer, reducing the influence of external electromagnetic interference on the internal signals of the circuit board, and also reducing the interference of the internal signals of the circuit board on external devices.

[0059] In some embodiments, as shown in FIG. 4, a plurality of receiving capacitors are provided near the signal processor on the first surface layer, and a plurality of pairs of receiving differential lines 21 on the first signal layer 16 are connected to the signal processor 4 through the corresponding receiving capacitors 41. A plurality of transmitting capacitors are provided at corresponding positions on the second surface layer, and a plurality of pairs of transmitting differential lines 22 on the second signal layer 17 are connected to the signal processor 4 through the corresponding transmitting capacitors 42. Figure 6 Figure 7 In some embodiments, as shown in FIG. 4, a plurality of receiving capacitors are provided near the signal processor on the first surface layer, and a plurality of pairs of receiving differential lines 21 on the first signal layer 16 are connected to the signal processor 4 through the corresponding receiving capacitors 41. A plurality of transmitting capacitors are provided at corresponding positions on the second surface layer, and a plurality of pairs of transmitting differential lines 22 on the second signal layer 17 are connected to the signal processor 4 through the corresponding transmitting capacitors 42.

[0060] The receiving capacitors 41 and the transmitting capacitors 42 are respectively provided in the receiving differential lines and the transmitting differential lines, for matching the impedance of each differential signal line, further optimizing the impedance matching performance of each signal transmission line, thereby reducing signal reflection and loss. In addition, the capacitors can be part of a filter, helping to filter out high-frequency noise or unwanted signal components, improving the signal-to-noise ratio of the signals.

[0061] With the number of differential signal line pairs doubled (from 16 pairs to 32 pairs, or even more), the wiring density increases significantly, posing higher technical challenges to wiring engineering, including fine signal integrity management, precise impedance matching control, and comprehensive electromagnetic compatibility considerations. The design of the printed circuit board of the present application realizes the optimal wiring of 32 pairs of receiving and transmitting differential signal lines of an eighteen-channel pluggable optical module, to ensure the high-frequency performance and stability of high-speed signal transmission.

[0062] In some embodiments, the present application also provides an optical module comprising the printed circuit board of any of the above embodiments.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.​

Claims

1. A printed circuit board, characterized in that, It includes a first surface layer and a second surface layer opposite to each other, and a plurality of inner layers stacked between the first surface layer and the second surface layer, the plurality of inner layers including a first signal layer and a second signal layer, the first surface layer being configured with at least one signal processor; One end of the printed circuit board is provided with an electrical connection portion, which includes a second transmitting end gold finger and a second receiving end gold finger located on the first surface layer, as well as a first transmitting end gold finger and a first receiving end gold finger located on the second surface layer. All gold fingers extend along the length direction of the printed circuit board. The first signal layer is provided with multiple pairs of receiving differential lines. One end of each pair of receiving differential lines is electrically connected to the signal processor. The other end of a portion of the multiple pairs of receiving differential lines is electrically connected to the first receiving terminal gold finger, and the other portion is electrically connected to the second receiving terminal gold finger. The second signal layer is provided with multiple pairs of transmit differential lines. One end of each pair of transmit differential lines is electrically connected to the signal processor. The other end of a portion of the transmit differential lines is electrically connected to the first transmitter gold finger, and the other portion is electrically connected to the second transmitter gold finger.

2. The printed circuit board according to claim 1, characterized in that, The electrical connection portion further includes power gold fingers located on the first surface layer and the second surface layer respectively. In the width direction of the printed circuit board, the power gold fingers are located in the middle of the electrical connection portion. The printed circuit board is divided into a first side and a second side by the power gold fingers and their extension lines. The first transmitting end gold fingers and the second transmitting end gold fingers are located on the first side, and the first receiving end gold fingers and the second receiving end gold fingers are located on the second side.

3. The printed circuit board according to claim 2, characterized in that, The plurality of pairs of receiving differential lines include: The first set of receiving differential lines, each pair of receiving differential lines includes a first receiving connection segment and a first receiving transmission segment. The first receiving connection segment is located in the second signal layer, and the first receiving transmission segment is located in the first signal layer. One end of the first receiving connection segment is projected onto the second surface layer and falls into the corresponding first receiving end gold finger, and is electrically connected to the corresponding first receiving end gold finger through conductive vias. The other end of the first receiving connection segment is electrically connected to the first receiving transmission segment through conductive vias. The second set of receiving differential lines, each pair of receiving differential lines includes a second receiving connection segment and a second receiving transmission segment, both of which are located in the first signal layer; one end of the second receiving connection segment is projected onto the first surface layer and falls into the corresponding second receiving end gold finger, and is electrically connected to the corresponding second receiving end gold finger through conductive vias, and the other end of the second receiving connection segment is connected to the second receiving transmission segment.

4. The printed circuit board according to claim 3, characterized in that, The projections of the first receiving connection segment and the second receiving connection segment onto the first surface fall into the power supply gold finger and the second side; one end of the first receiving transmission segment is electrically connected to the signal processor on the first side and extends along the length direction within the first side, while the other end extends obliquely from the first side to the second side to be electrically connected to the first receiving connection segment; one end of the second receiving transmission segment is electrically connected to the signal processor on the second side and is connected to the second receiving connection segment within the second side.

5. The printed circuit board according to claim 3, characterized in that, Both the first receiving end gold fingers and the second receiving end gold fingers include a first row of gold fingers and a second row of gold fingers arranged along the length direction. The second row of gold fingers is relatively close to the signal processor and is insulated from the first row of gold fingers. In the width direction, in the arrangement order from the second side to the first side, the odd-numbered pairs of differential lines of the first group of receiving differential lines are electrically connected to the second row of gold fingers of the first receiving end gold fingers, and the even-numbered pairs of differential lines are electrically connected to the first row of gold fingers of the first receiving end gold fingers. Similarly, the odd-numbered pairs of differential lines of the second group of receiving differential lines are electrically connected to the first row of gold fingers of the second receiving end gold fingers, and the even-numbered pairs of differential lines are electrically connected to the second row of gold fingers of the second receiving end gold fingers.

6. The printed circuit board according to claim 2, characterized in that, The plurality of pairs of transmit differential lines include: The first set of transmit differential lines, each pair of transmit differential lines includes a first transmit connection segment and a first transmit transmission segment, both of which are located in the second signal layer; one end of the first transmit connection segment is projected onto the second surface layer into the corresponding first transmitter gold finger, and is electrically connected to the corresponding first transmitter gold finger through conductive vias; the other end of the first transmit connection segment is connected to the first transmit transmission segment. The second set of transmit differential lines, each pair of transmit differential lines includes a second transmit connection segment and a second transmit transmission segment. The second transmit connection segment is located in the first signal layer, and the second transmit transmission segment is located in the second signal layer. One end of the second transmit connection segment is projected onto the first surface layer and falls into the corresponding second transmitter gold finger, and is electrically connected to the corresponding second transmitter gold finger through conductive vias. The other end of the second transmit connection segment is electrically connected to the second transmit transmission segment through conductive vias.

7. The printed circuit board according to claim 6, characterized in that, The projections of the first transmitting connection segment and the second transmitting connection segment on the second surface fall into the power gold finger and the first side; one end of the first transmitting transmission segment is electrically connected to the signal processor on the first side and connected to the first transmitting connection segment inside the first side. One end of the second transmission segment is electrically connected to the signal processor on the second side and extends along the length direction within the second side, while the other end extends obliquely from the second side to the first side to be electrically connected to the second transmission segment.

8. The printed circuit board according to claim 6, characterized in that, Both the first transmitter gold finger and the second transmitter gold finger include a first row of gold fingers and a second row of gold fingers arranged along the length direction. The second row of gold fingers is relatively close to the signal processor and is insulated from the first row of gold fingers. In the width direction, in the arrangement order from the first side to the second side, the odd-numbered pairs of differential lines of the first group of transmitting differential lines are electrically connected to the first row of gold fingers of the first transmitting end gold fingers, and the even-numbered pairs of differential lines are electrically connected to the second row of gold fingers of the first transmitting end gold fingers. The odd-numbered pairs of differential lines of the second group of transmitting differential lines are electrically connected to the second row of gold fingers of the second transmitting end gold fingers, and the even-numbered pairs of differential lines are electrically connected to the first row of gold fingers of the second transmitting end gold fingers.

9. The printed circuit board according to claim 3 or 5, characterized in that, The conductive vias are respectively connected to the ends of the first receiving end gold fingers, the second receiving end gold fingers, the first transmitting end gold fingers, and / or the second transmitting end gold fingers that are relatively close to the processor.

10. The printed circuit board according to claim 1, characterized in that, The printed circuit board also includes a ground layer located between the first signal layer and the second signal layer, which is used to isolate the transmit differential line and the receive differential line.

11. The printed circuit board according to claim 1, characterized in that, The first transmitting end gold finger, the second transmitting end gold finger, the first receiving end gold finger, and the second receiving end gold finger all include multiple sets of differential signal gold fingers arranged along the width direction, and each set of differential signal gold fingers has grounding gold fingers on both sides.

12. The printed circuit board according to claim 1, characterized in that, The first signal layer is provided with 16 pairs of receiving differential lines, of which 8 pairs of receiving differential lines are electrically connected to the gold fingers of the first receiving end, and the other 8 pairs of receiving differential lines are electrically connected to the gold fingers of the second receiving end. The second signal layer is provided with 16 pairs of transmit differential lines, of which 8 pairs of transmit differential lines are electrically connected to the gold fingers of the first transmitter end, and the other 8 pairs of transmit differential lines are electrically connected to the gold fingers of the second transmitter end.

13. An optical module, characterized in that, The optical module includes a printed circuit board as described in any one of claims 1-12.

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