Vertically packaged TO-CAN assembly with refrigerator

Abstract

The utility model belongs to the technical field of high-speed optical communication application, and discloses a vertically packaged TO-CAN assembly with a refrigerator, the TO-CAN assembly comprises a 7PIN tube socket and a tube cap sealing cap, the top of the 7PIN tube socket is provided with a TO tube socket boss, the side surface of the TO tube socket boss is pasted with a second TEC, the side surface of the second TEC is pasted with a second LD substrate, and the top of the second TEC is provided with a second LD substrate. A TO tube base boss is attached to the top of the second LD substrate, a second MPD is attached to the side face of the second LD substrate, an AC circuit in the second LD substrate is directly bonded with an AC pin through a gold wire, a tube cap sealing cap is arranged at the top of the 7PIN tube base, and the tube cap sealing cap packages the TO tube base boss, the second MPD and a thermistor fixed in the second LD substrate at the top of the 7PIN tube base. The utility model has the beneficial effects that the routing distance from the high-speed AC PIN to the substrate is shorter, the gold wire consumption is lower, and the key point is that the TEC directly adopts a vertical packaging mode, so that a low-cost tube socket can be adopted, a tube socket preset adapter plate is omitted, and the cost of the tube socket is greatly reduced.

Description

Technical Field

[0001] This utility model belongs to the field of high-speed optical communication application technology, and in particular relates to a vertically packaged TO-CAN component with a cooler. Background Technology

[0002] Optical fiber communication is a communication method that uses light waves as the information carrier and optical fibers as the transmission medium. Optical fibers have the advantages of large capacity and low loss. Modern high-speed optical communication usually requires multiple wavelengths to carry multiple communication channels, and with the growth of communication traffic, the number of wavelengths required is increasing.

[0003] For example, the 10G PON (Passive Optical Networks) system widely used in access networks includes downlink wavelengths of 1577nm and 1490nm and uplink wavelengths of 1270nm and 1310nm. Among them, the 1577nm wavelength requires a packaging solution with TEC. TEC can stabilize the operating temperature of the laser, thereby stabilizing the operating wavelength of the laser, and can also ensure that the output optical power of the laser meets the requirements in high-temperature operating environments.

[0004] In the next-generation 50G-PON system, in addition to the four wavelengths of 10G-PON, two more wavelengths, 1342nm and 1286nm, have been added. Thus, there are six wavelengths in a single optical fiber in the access network. The two newly added wavelengths, 1342nm and 1286nm, both require a TEC-equipped packaging solution to ensure that the wavelength of the laser is within the standard requirement range, while also meeting the optical power requirements in high-temperature environments.

[0005] 5G fronthaul transport solutions are mainly divided into fiber-optic direct-drive solutions and wavelength division multiplexing (WDM) equipment-based solutions. There are many variations of WDM solutions, ranging from passive CWDM to semi-active LWDM and MWDM, as well as tunable DWDM. The mainstream 6-wavelength CWDM solution can basically meet the deployment needs of 5G. However, facing complex situations such as 5G and 4G co-construction and operator co-construction and sharing (e.g., China Telecom and China Unicom jointly building 5G base stations), an additional 12 wavelengths are needed, requiring a 12-wavelength WDM solution. LWDM and MWDM 12-wavelength fronthaul solutions have thus emerged. Because the wavelength spacing of 12 waves is shortened, temperature control (TEC) is also required to support the use of 12 waves.

[0006] In summary, more and more applications require the coexistence of multiple wavelengths, and TO-CAN, or laser diode module, is the lowest cost and most widely used packaging form; therefore, TO packages with TEC are widely adopted.

[0007] Taking the 1577nm TO required for 10G-PON as an example, the current mainstream solution on the market is the EML vertical packaging solution, such as...Figure 1 As shown, it includes an 8PIN prefabricated substrate socket (1), a first TEC (2), a WCU (3), a first MPD (4), an NTC (5), a first LD substrate (6), a first LD (7), a 100pf (8), and a 10nf (9); wherein the first TEC adopts a traditional horizontal mounting, and the other components are on top of the first TEC. A heat sink made of a material with high thermal conductivity, such as tungsten copper or aluminum nitride, is mounted on the first TEC, and the LD substrate is mounted on the heat sink, thus realizing the vertical packaging of the laser.

[0008] However, due to intense market competition and enormous product cost pressures, current packaging methods have the following weaknesses in terms of both technical solutions and packaging costs:

[0009] 1. To ensure high-frequency signal transmission, a custom-made prefabricated substrate socket with high-frequency signal transmission is required. The cost of materials such as the socket and LD substrate is relatively high.

[0010] 2. The prefabricated substrate for the tube socket needs to be soldered to the tube socket pins using gold solder, which is expensive.

[0011] 3. Gold and tin require high-temperature reflow furnace sintering. At high temperatures, the difference in expansion coefficients between AC glass and tube base can easily cause minor leaks. Summary of the Invention

[0012] The purpose of this utility model embodiment is to provide a vertically packaged TO-CAN component with a cooler, aiming to solve the technical problem that the cost of materials such as the prefabricated substrate socket with high-frequency signal transmission, the socket, and the LD substrate is high in order to ensure high-frequency signal transmission.

[0013] The present invention is implemented as follows:

[0014] A vertically packaged TO-CAN assembly with a cooler, the TO-CAN assembly including a 7-pin socket and a cap, the top of the 7-pin socket having a TO-pin socket boss, a second TEC attached to the side of the TO-pin socket boss, a second LD substrate attached to the side of the second TEC, a second MPD attached to the side of the second LD substrate, AC lines in the second LD substrate being directly bonded to AC pins via gold wires, the top of the 7-pin socket having a cap, the cap encapsulating the TO-pin socket boss, the second MPD, and a thermistor fixed in the second LD substrate on the top of the 7-pin socket.

[0015] Furthermore, the TO socket boss and the 7PIN socket are an integral structure, and the TO socket boss is a protrusion on the top of the 7PIN socket.

[0016] Furthermore, the TO tube seat boss is an ALN ​​heat sink or a tungsten copper heat sink.

[0017] Furthermore, the TO tube seat boss is semi-cylindrical.

[0018] Furthermore, a second TEC is attached to the side of the TO tube seat boss with silver paste, a COC substrate is attached to the side of the second TEC with silver paste, and a second MPD is attached to the side of the COC substrate with silver paste.

[0019] The advantages of this invention are as follows: The TO-CAN assembly with a cooler and a vertically packaged cooler internally employs a direct modulation laser (DML). The DML laser uses a vertical design, and the TEC is also fixed to the socket boss through a vertical package. High-frequency circuit connection is achieved by directly bonding the AC pins to the AC lines of the second LD substrate. Compared with the conventional horizontal mounting of the first TEC in the prior art, and the other components being on top of the first TEC, this results in a shorter wire bonding distance from the high-speed AC pin to the substrate and less gold wire consumption. Crucially, the TEC uses a vertical package, allowing for the use of a low-cost socket, eliminating the need for a pre-installed adapter board on the socket, and significantly reducing socket costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a vertically packaged TO-CAN component with a cooler, which is an improvement on the prior art.

[0021] Figure 2 yes Figure 1 The figure shown is a three-dimensional structural diagram of a vertically packaged TO-CAN component with a cooler according to this utility model.

[0022] Figure 3 yes Figure 2 The image shows a side view of a vertically packaged TO-CAN assembly with a cooler according to this invention.

[0023] Legend: 1—8PIN prefabricated substrate socket, 2—First TEC, 3—WCU, 4—First MPD, 5—NTC, 6—First LD substrate, 7—First LD, 8—100pf, 9—10nf, 10—7PIN socket, 11—Second TEC, 12—Second LD substrate, 13—Second LD, 14—Second MPD, 15—Thermistor, 16—AC pin, 17—TO socket boss;

[0024] Among them, TEC stands for Thermoelectric Cooler, WCU stands for Wireless Control Unit, MPD stands for Monitor Photodiode, NTC stands for Negative Temperature Coefficient Thermistor, LD stands for Laser Diode, 100pf is a 10 nanofarad (nF) capacitor inside the package or between the pins, 10nf is a 10 nanofarad (nF) capacitor, and AC pin is the Anode-Cathode pin. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0026] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0027] The terms "first" and "second" in this application are used only to distinguish the same device in different structures and do not imply that they have different functions.

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0029] like Figure 2 and Figure 3The diagram shown is a structural diagram of a vertically packaged TO-CAN assembly with a cooler provided in an embodiment of this utility model. It includes a 7-pin connector 10, a TO connector boss 17 on the top of the 7-pin connector 10, a second TEC 11 attached to the side of the TO connector boss 17, a second LD substrate 12 attached to the side of the second TEC 11, a second MPD 14 attached to the side of the second LD substrate 12, and an AC line in the second LD substrate 12 directly bonded to the AC pin 16 via gold wire. A connector cap is provided on the top of the 7-pin connector 10, which encapsulates the TO connector boss 17, the second MPD 14, and the thermistor 15 fixed in the second LD substrate on the top of the 7-pin connector 10.

[0030] The second LD substrate is also known as the COC substrate, and the second LD is also known as the direct modulated laser (DML).

[0031] The second TEC chip is mounted on the TO socket boss, the COC substrate chip is mounted on the TEC, the second MPD chip is mounted on the COC substrate, the AC circuit in the COC substrate is directly bonded to the pins via gold wire, and finally sealed with a TO cap; all chips are fixed with silver paste, and the circuit is connected with gold wire; the operating temperature of the second LD is controlled by the second TEC and the thermistor.

[0032] From the perspective of the optical path: the light emitted from the second LD13 is coaxial through design and patch and cap control, and after passing through the TO tube cap, it is coupled into the optical fiber through the lens; the light emitted from the second LD13 is monitored by the second MPD14.

[0033] In this invention, the TO-CAN assembly with a cooler and a vertically packaged cooler internally employs a direct modulation laser (DML). The DML laser is vertically mounted, and the TEC is also vertically packaged and fixed to the socket boss. High-frequency circuitry is achieved through direct bonding of the AC pins to the AC lines of the second LD substrate. Compared to the conventional horizontal mounting of the first TEC in existing technologies, and with other components positioned on top of the first TEC, this design results in a shorter wire bonding distance from the high-speed AC pins to the substrate, reducing gold wire consumption. Crucially, the TEC's vertical packaging allows for the use of a low-cost socket, eliminating the need for a pre-installed adapter board and significantly reducing socket costs.

[0034] Alternatively, a socket without a boss can be used, further reducing the socket cost. A heatsink made of tungsten copper or aluminum nitride is added, which also serves a fixing function. The TEC is fixed to this heatsink using a vertical package.

[0035] In this invention, the packaging of a direct-modulated laser (DML) is used as an example. An externally modulated laser (EML) can also be packaged in a similar manner.

[0036] Preferably, the AC pin 16 and the second LD substrate 12 are on the same plane, and the structural design minimizes the wire bonding distance from the high-speed AC pin to the substrate.

[0037] The front light-emitting surface of the second LD13 on the second LD substrate 12 is located at the front focal point of the non-spherical tube cap design to ensure the focal length requirement and to minimize the distance between the AC line and the AC pin of the tube socket, thus ensuring the shortest possible wire length in the AC line. Furthermore, the second LD substrate 12 adopts a single-ended 25-ohm gold layer circuit design that achieves coplanar single-ended input of GSGSG and impedance matching with the high-frequency circuit, which can reduce high-frequency signal reflection and ensure high-frequency signal quality.

[0038] Preferably, the TO socket boss is an ALN ​​heatsink or a tungsten copper heatsink; replacing the TO socket boss with an ALN ​​heatsink includes: a low-cost 7-pin socket 10, a second TEC 11, a second LD substrate 12, a second LD 13, a second MPD 14, a thermistor 15, an ALN, with the ALN chip mounted on the TO socket boss, the TEC chip mounted on the ALN, the COC substrate chip mounted on the TEC, and the MPD chip mounted on the COC substrate. The AC line is directly bonded to the pins via gold wire, and finally, the TO socket is capped. All chips are fixed with silver paste, and the circuit is connected with gold wire. The LD operating temperature is controlled by the TEC and the thermistor.

[0039] Aluminum nitride (AlN), as a ceramic material, does indeed possess high thermal conductivity, approximately 140-180 W / mK, which is significantly higher than that of alumina (Al₂O₃), which is approximately 20-30 W / mK. Therefore, in packages requiring efficient heat dissipation, AlN may be used as a substrate or insulating layer.

[0040] The foregoing has broadly outlined some aspects and features of the various embodiments and should be interpreted as merely illustrative of potential applications. Other beneficial results can be obtained by applying the disclosed information in different ways or by combining aspects of the disclosed embodiments. Further aspects and a more complete understanding can be obtained based on the detailed description of exemplary embodiments with reference to the accompanying drawings, within the scope defined by the claims.

[0041] The above embodiments provide a detailed description of the present invention. Of course, the above description is not intended to limit the present invention, nor is the present invention limited to the examples described above. Any changes, modifications, additions, reductions, or substitutions made by those skilled in the art within the scope of the present invention are also within the protection scope of the present invention.

Claims

1. A vertically packaged TO-CAN assembly with a cooler, characterized in that, The TO-CAN assembly includes a 7-pin socket and a cap. The top of the 7-pin socket has a TO socket boss. A second TEC is attached to the side of the TO socket boss. A second LD substrate is attached to the side of the second TEC. A second MPD is attached to the side of the second LD substrate. The AC line in the second LD substrate is directly bonded to the AC pin through gold wire. The top of the 7-pin socket has a cap. The cap encapsulates the TO socket boss, the second MPD, and the thermistor fixed in the second LD substrate on the top of the 7-pin socket.

2. The vertically packaged TO-CAN assembly with a cooler according to claim 1, characterized in that, The TO socket boss and the 7PIN socket are an integral structure, and the TO socket boss is a protrusion on the top of the 7PIN socket.

3. The vertically packaged TO-CAN assembly with a cooler according to claim 2, characterized in that, The TO tube seat boss is an ALN ​​heat sink or a tungsten copper heat sink.

4. A vertically packaged TO-CAN assembly with a cooler according to any one of claims 1 to 3, characterized in that, The TO tube seat boss is semi-cylindrical.

5. A vertically packaged TO-CAN assembly with a cooler according to claim 4, characterized in that, The side of the TO tube seat boss is attached with a second TEC by silver paste, the side of the second TEC is attached with a COC substrate by silver paste, and the side of the COC substrate is attached with a second MPD by silver paste.

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