Vertical coupling packaging structure and preparation method thereof

Abstract

The invention provides a vertical coupling packaging structure and a preparation method thereof. The vertical coupling packaging structure comprises a heat sink which comprises a first surface and a second surface which are vertical to each other; the detector chip is arranged on the first surface, a photosensitive surface is formed on the detector chip, and the photosensitive surface is parallel to the first surface; the radio frequency transmission line is arranged on the first surface and located on the first side of the detector chip, and the radio frequency transmission line is electrically connected with the photosensitive surface; the direct-current adapter plate is arranged on the first surface and located on the second side of the detector chip, the second side is opposite to the first side, and the direct-current adapter plate is electrically connected with the photosensitive surface; and the plane optical fiber is arranged on the second surface, and a light outlet of the plane optical fiber right faces the photosensitive surface. The vertical coupling packaging structure not only can solve the problem that the responsivity is reduced due to low coupling efficiency, but also can ensure the signal integrity of the radio-frequency signal, so that the radio-frequency signal reaches an ideal bandwidth level.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic integrated device packaging, and more specifically to a vertically coupled packaging structure and its fabrication method. Background Technology

[0002] With the development of modern mobile internet, the amount of information transmitted is growing exponentially. Electrical interconnects have shown their limitations, failing to meet the bandwidth and speed requirements of massive data transmission in information systems. Optical interconnects, using photons as the information transmission medium, are gradually replacing electrical interconnects as the mainstream technology for medium- and long-distance low-loss transmission due to their advantages of low loss and high bandwidth.

[0003] A complete optical interconnect communication system consists of an optical transmitter, an optical transmission link, and an optical receiver, with the photodetector being the core component of the optical receiver. Photodetectors are mainly classified into two types based on the light incidence method: surface-incidence and waveguide-coupled, suitable for different application scenarios. Waveguide-structured silicon-based germanium photodetectors are easily integrated with other optical waveguide devices and are suitable for applications such as on-chip optical interconnects. Surface-incidence structured optically coupled devices are simple, efficient, and flexible in use, suitable for optical communication, optical interconnects, optical sensing, and optical receiver modules.

[0004] Optical coupling design is a crucial step in the packaging process of optical receiver modules, as coupling efficiency directly affects characteristics such as device responsivity and system sensitivity. Therefore, how to improve coupling efficiency while ensuring bandwidth levels is an important issue in this field. Summary of the Invention

[0005] In view of this, the present invention provides a vertically coupled packaging structure and its fabrication method to solve the problem that bandwidth and responsivity cannot be simultaneously achieved after packaging a broadband surface incident photodetector chip.

[0006] The present invention provides a vertically coupled packaging structure, comprising: a heat sink, including a first surface and a second surface perpendicular to each other; a detector chip disposed on the first surface, wherein a photosensitive surface is formed on the detector chip and the photosensitive surface is parallel to the first surface; a radio frequency transmission line disposed on the first surface and located on a first side of the detector chip, the radio frequency transmission line being electrically connected to the photosensitive surface; a DC-DC converter plate disposed on the first surface and located on a second side of the detector chip, the second side being opposite to the first side, the DC-DC converter plate being electrically connected to the photosensitive surface; and a planar optical fiber disposed on the second surface, wherein the light outlet of the planar optical fiber faces the photosensitive surface.

[0007] According to an embodiment of the present invention, the projection center of the planar optical fiber on the first surface coincides with the center of the photosensitive surface.

[0008] According to an embodiment of the present invention, the long axis of the detector chip and the long axis of the radio frequency line are both parallel to the second surface.

[0009] According to an embodiment of the present invention, a positive electrode portion and a ground electrode portion are formed on the DC adapter board. The ground electrode portion is treated with a via, and the positive electrode portion is treated with a side semi-encapsulated metallization.

[0010] According to an embodiment of the present invention, the vertically coupled package structure further includes: a first capacitor disposed on the first surface and located between the first side and the second side, the input terminal of the first capacitor being connected to a DC-DC converter board, the output terminal of the first capacitor being connected to the DC pad of the detector chip, and the first capacitor being used to filter the voltage signal transmitted from the DC-DC converter board to the detector chip.

[0011] According to an embodiment of the present invention, the vertically coupled package structure further includes: a second capacitor coupled to the DC-DC adapter board, the second capacitor being used to stabilize the bias voltage generated by the DC-DC adapter board.

[0012] According to an embodiment of the present invention, the vertically coupled packaging structure further includes: a metal shell, including a first tube wall, a second tube wall and a third tube wall, the first tube wall and the third tube wall being parallel, the second tube wall being vertically connected between the first tube wall and the third tube wall, a heat sink being disposed in the cavity surrounded by the first tube wall, the second tube wall and the third tube wall, and the first tube wall being opposite to the first surface.

[0013] According to an embodiment of the present invention, a first through hole is formed on the first tube wall, and a DC pin is disposed in the first through hole. The DC pin is connected to the input terminal of the DC adapter board through a gold wire. A second through hole is formed on the second tube wall, and a planar optical fiber is disposed on the second surface after passing through the second through hole. A third through hole is formed on the third tube wall, and an RF feedout component is disposed in the third through hole. The RF feedout component is connected to the output terminal of the RF transmission line.

[0014] Another aspect of the present invention provides a method for fabricating the above-mentioned vertically coupled packaging structure, comprising: sequentially mounting a DC-DC converter board, a detector chip, and an RF transmission line on a first surface of a heat sink, wherein the DC-DC converter board and the RF transmission line are located on opposite sides of the detector chip; electrically connecting the output end of the DC-DC converter board to the input end of the detector chip, and electrically connecting the output end of the detector chip to the output end of the RF transmission line; fixing a planar optical fiber on a second surface of the heat sink such that the light outlet of the planar optical fiber faces the photosensitive surface of the detector chip, and the first and second surfaces are perpendicular to each other.

[0015] According to an embodiment of the present invention, fixing the planar optical fiber on the second surface of the heat sink includes: adjusting the distance between the light outlet and the photosensitive surface to determine the target position of the planar optical fiber on the second surface; and fixing the planar optical fiber at the target position.

[0016] Based on the above, a vertically coupled packaging scheme for a broadband planar incident photodetector chip is achieved by placing a DC-DC converter board, a detector chip, and an RF transmission line on one surface of the heat sink, and a planar optical fiber on the other vertical surface of the heat sink. This scheme improves coupling efficiency and, through clever structural design, avoids 90-degree switching of the RF signal, thus ensuring signal integrity and achieving an ideal bandwidth level, fully leveraging the superior performance of the planar incident detector chip. The vertically coupled packaging structure of this invention is simple and low-cost, which is beneficial for promoting the development of optoelectronic chip integrated packaging. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0018] Figure 1 A schematic three-dimensional view of a vertically coupled packaging structure according to an embodiment of the present invention is shown.

[0019] Figure 2 A schematic diagram illustrates a plan view of a vertically coupled packaging structure on a first surface according to an embodiment of the present invention;

[0020] Figure 3 A schematic plan view of a detector chip according to an embodiment of the present invention is shown;

[0021] Figure 4 A flowchart illustrating a method for fabricating a vertically coupled packaging structure according to an embodiment of the present invention is shown. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0024] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0025] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). When using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0026] For surface-incident photodetectors, the coupling alignment can be categorized into horizontal and vertical coupling based on the orientation of the fiber relative to the detector's photosensitive surface. Horizontal coupling involves placing the detector's photosensitive surface upwards, using a beveled fiber positioned horizontally. Light incident horizontally on the beveled fiber undergoes total internal reflection upon passing through the bevel interface, altering its propagation direction and allowing it to pass through the core and cladding before entering the detector's photosensitive surface, thus achieving coupling. However, the outgoing beam of a beveled fiber is larger than that of a flat / tapered fiber. If the detector's photosensitive surface area is smaller than the outgoing beam, some light loss cannot be absorbed by the detector, reducing coupling efficiency and consequently decreasing the responsivity and sensitivity of the packaged photodetector module. In detector packaging, vertical coupling requires the planar optical fiber to be placed vertically and the detector chip to be mounted vertically. However, the radio frequency (RF) signal converted by the detector needs to be transmitted horizontally, necessitating the addition of a 90-degree RF transition thin-film circuit. This method makes the packaging process complex and affects the high-frequency performance of the device. Therefore, this vertical coupling packaging structure is only suitable for detectors with low bandwidth requirements for low-frequency transmission. However, with technological advancements, the size of high-speed detector chips is decreasing, and the area of ​​the photosensitive surface is correspondingly shrinking, rendering the above coupling method unsuitable.

[0027] In view of this, the present invention provides a novel vertically coupled packaging structure and fabrication method based on a surface-incident photodetector. While improving coupling efficiency, it can avoid the 90-degree conversion of radio frequency signals to achieve high-frequency signal transmission, thereby solving the problem that bandwidth and responsivity cannot be simultaneously achieved after packaging a broadband surface-incident photodetector module.

[0028] Figure 1 A schematic three-dimensional view of a vertically coupled packaging structure according to an embodiment of the present invention is shown. Figure 2 A schematic diagram illustrates a plan view of a vertically coupled packaging structure on a first surface according to an embodiment of the present invention; Figure 3 A schematic plan view of a detector chip according to an embodiment of the present invention is shown. Figures 1-3 In this context, identical parts use the same numbering system.

[0029] like Figure 1 As shown, the vertically coupled packaging structure 100 may include a heat sink 2, a DC-DC converter board 3, a detector chip 4, an RF transmission line 5, and a planar optical fiber 8.

[0030] The heat sink 2 may include a first surface 21 and a second surface 22, which are perpendicular to each other. The first surface 21 and the second surface 22 can be directly connected together, such as... Figure 1 As shown, an L-shaped structure can be formed. In some other embodiments, the connection between the first surface 21 and the second surface 22 can have a transition surface, such as an arc surface or a plane. That is, the first surface 21 and the second surface 22 can also be indirectly connected. The present invention does not limit the specific connection method.

[0031] like Figure 1 As shown, a DC-DC converter board 3, a detector chip 4, and an RF transmission line 5 are disposed on the first surface 21. A planar optical fiber 8 is disposed on the second surface 22.

[0032] like Figure 3 As shown, a photosensitive surface is formed on the detector chip 4, which is parallel to the first surface 21 and can be used to receive and sense optical signals. DC pads and RF pads are also formed on the detector chip 4. The function of the detector chip 4 is to convert optical signals into electrical signals.

[0033] like Figure 1 , Figure 2 and Figure 3As shown, the RF transmission line 5 is located on the first side of the detector chip 4 (right side in the figure), and the RF pads of the detector chip 4 and the RF transmission line 5 are interconnected by gold wire bonding. The RF transmission line 5 can be used to transmit the electrical signals generated by the detector chip 4 to external circuits (not shown in the figure) through the RF pads. Its high-frequency transmission characteristics ensure the integrity and accuracy of the signal. The DC-DC converter board 3 is located on the second side of the detector chip 4 (left side in the figure, opposite to the right side), and is also connected to the DC pads of the detector chip 4 by gold wire bonding. The DC-DC converter board 3 can be used to transmit the DC bias voltage provided by the external power supply (not shown in the figure) to the detector chip 4 and realize the electrical connection between the detector chip 4 and the external circuit. The light outlet of the planar optical fiber 8 faces the photosensitive surface of the detector chip 4.

[0034] In the vertically coupled package structure 100, the photosensitive surface of the detector chip 4 receives the optical signal transmitted by the planar optical fiber 8. Under the action of DC bias, the optical signal is converted into an electrical signal and transmitted to the radio frequency transmission line 5, and then transmitted to the external circuit through the radio frequency feedout component of the metal casing 1. During this process, the heat sink 2 can effectively conduct away the heat generated by these components, ensuring the stable operation of the vertically coupled package structure 100. At the same time, the heat sink 2 also provides support for these components, keeping the relative positions of each component fixed.

[0035] Conventional vertical coupling introduces a 90° bend in RF signal transmission, severely impacting the high-frequency performance of devices and hindering the practical application of ultra-wideband incident detector chips. The vertical coupling package structure 100 provided in this embodiment cleverly utilizes an "L"-shaped heat sink and a 90° DC adapter to avoid the 90° bend in RF signal transmission, ensuring grounding continuity. This solves the problem of low coupling efficiency leading to decreased responsivity while also guaranteeing RF signal integrity, achieving an ideal bandwidth level.

[0036] Please continue reading. Figure 1 Based on the above embodiments, the projection center of the planar optical fiber 8 on the first surface 21 can coincide with the center of the photosensitive surface. That is, the planar optical fiber 8 is vertically aligned with the photosensitive surface, so that light can be better received by the photosensitive surface. This coincidence ensures that when the optical signal is transmitted from the output port of the planar optical fiber 8 to the photosensitive surface, it can be transmitted with minimal loss and maximum efficiency.

[0037] Please see Figure 2Based on the above embodiments, the long axis of both the detector chip 4 and the RF line 5 is parallel to the second surface 22. In other words, both the detector chip 4 and the RF line 5 are placed in a direction parallel to the second surface 22. This avoids deflections in the RF signal and helps ensure the stability and consistency of the RF signal during transmission. In some embodiments, the long axis of the detector chip 4 and the long axis of the RF line 5 may also coincide to simplify alignment and connection steps.

[0038] Based on the above embodiment, the DC-DC adapter board 3 has a positive electrode portion and a ground electrode portion. The positive electrode portion is the part of the DC-DC adapter board 3 used to connect positive circuit components or power supplies. The ground electrode portion is the part of the DC-DC adapter board 3 used to connect ground or ground circuit components. The ground electrode portion employs via treatment, that is, through holes are formed in the ground electrode portion, and through these through holes, the ground electrode portion is connected to other layers or components of the circuit board, which helps to enhance the conductivity and stability of the ground electrode portion and ensure the reliability and safety of the ground connection. The positive electrode portion employs side semi-encased metallization treatment, that is, a metal film or metal layer is coated on the side of the positive electrode portion. Through the treatment of the electrodes of the DC-DC adapter board 3, a 90-degree transition of DC bias voltage can be achieved.

[0039] Please see Figure 1 and Figure 2 The vertically coupled package structure 100 may further include a first capacitor 7, disposed on the first surface 21 and located between the first and second sides. The upper surface of the first capacitor 7 is connected to the DC pads of the DC-DC converter board 3 and the detector chip, and the lower surface is tightly attached to the plane of the heat sink 21 with conductive silver paste. The first capacitor is used to filter the voltage signal transmitted from the DC-DC converter board 3 to the detector chip 4.

[0040] The vertically coupled package structure 100 may also include a second capacitor 6, coupled to the DC-DC adapter board 3. The second capacitor 6 is used to stabilize the bias voltage generated by the DC-DC adapter board 3 and prevent the detector chip 4 from breaking down during sudden power switching.

[0041] Please continue reading. Figure 1 The vertically coupled encapsulation structure 100 may further include a metal housing 1. The metal housing 1 may include a first wall 11, a second wall 12, and a third wall 13. The first wall 11 and the third wall 13 are parallel, and the second wall 12 is vertically connected between the first wall 11 and the third wall 13. The heat sink 2 is disposed within the cavity formed by the first wall 11, the second wall 12, and the third wall 13, with the first wall 11 facing the first surface 21. The metal housing 1 provides support for the heat sink 2 and protects the various components on the heat sink 2. Simultaneously, it provides a relatively sealed environment to ensure that the photosensitive surface receives light from the planar optical fiber 8, avoiding interference from other light sources.

[0042] A first through-hole is formed on the first tube wall 11, and a DC pin 10 is disposed in the first through-hole. The DC pin 10 is connected to the input terminal of the DC adapter board 3 through a gold wire 9. A second through-hole is formed on the second tube wall 12. The planar optical fiber 8 passes through the second through-hole and is disposed on the second surface 22, ensuring that the light outlet of the planar optical fiber 8 is directly facing the photosensitive surface of the detector chip 4, thereby realizing accurate transmission of optical signals. A third through-hole is formed on the third tube wall 13, and an RF feed component 11 is disposed in the third through-hole. The RF feed component 11 is connected to the output terminal of the RF transmission line 5.

[0043] Based on the above-described vertically coupled packaging structure, this invention also provides a method for fabricating the vertically coupled packaging structure. The following is combined with... Figure 4 This should be explained. It should be noted that this preparation method has the same or similar technical features and beneficial effects as the vertically coupled packaging structure.

[0044] Figure 4 A flowchart illustrating a method for fabricating a vertically coupled packaging structure 100 according to an embodiment of the present invention is shown.

[0045] like Figure 4 As shown, the method for fabricating a vertically coupled packaging structure may include steps S410 to S430.

[0046] In step S410, a DC adapter board 3, a detector chip 4, and an RF transmission line 5 are sequentially mounted on the first surface 21 of the heat sink 2. The DC adapter board 3 and the RF transmission line 5 are located on opposite sides of the detector chip 4.

[0047] As an example, a conductive adhesive can be used to mount the DC-DC adapter board 3, the detector chip 4, and the RF transmission line 5 onto the heat sink 2. The conductive adhesive can be, for example, prepared by mixing silver resin paste and a liquid hardener in a 1:1 ratio. After mounting, the heat sink can be placed in a constant-temperature oven for curing.

[0048] In some embodiments, the first capacitor 7 and the second capacitor 6 may also be simultaneously mounted on the heat sink 2. The mounting positions of the first capacitor 7 and the second capacitor 6 have been described above, so they will not be repeated here.

[0049] The pre-installed heat sink 2 can be attached to the prepared metal housing 1. For example, conductive adhesive can be evenly applied to the bonding area of ​​the metal housing 1 cavity. After the conductive adhesive is applied, the heat sink 2 is placed into the cavity and fixed inside the metal housing 1. Conductive adhesive can be used to connect the signal lines of the insulator and the RF thin film circuit. After completion, it is placed in a constant temperature oven for curing.

[0050] In step S420, the output terminal of the DC adapter board 3 is electrically connected to the input terminal of the detector chip 4, and the output terminal of the detector chip 4 is electrically connected to the output terminal of the radio frequency transmission line 5.

[0051] Electrical connections between the DC-DC adapter board 3, detector chip 4, and RF transmission line 5 can be achieved via gold wire bonding. For example, the positive terminal, first capacitor 7, detector chip 4, and RF transmission line 5 on the DC-DC adapter board 3 can be connected via wedge soldering, and the DC pin 10 of the metal housing 1 and the positive terminal of the DC-DC adapter board 3 can be connected via ball soldering.

[0052] In step S430, the planar optical fiber 8 is fixed on the second surface 22 of the heat sink 2, so that the light outlet of the planar optical fiber 8 is facing the photosensitive surface of the detector chip 4, and the first surface 21 and the second surface 22 are perpendicular to each other.

[0053] In some embodiments, fixing the planar optical fiber 8 to the second surface 22 of the heat sink 2 may include: adjusting the distance between the light outlet and the photosensitive surface to determine the target position of the planar optical fiber 8 on the second surface 22; and fixing the planar optical fiber 8 at the target position.

[0054] As an example, the gold wire bonded device can be fixed onto the coupling stage, and the position of the detector chip 4 can be observed through a video microscope lens. A DC bias voltage can be provided to the detector chip 4 using a digital source meter. The planar optical fiber 8 can be mounted onto the optical fiber fixing fixture and tightened with screws. Then, the output wavelength and optical output power of the tunable light source can be set to appropriate values. The moving coupling stage allows the planar optical fiber 8 to enter through the second tube wall 12 of the metal housing 1. The center of the planar optical fiber 8 is then aligned with the center of the photosensitive surface of the detector chip 4, and the current value displayed on the digital source meter is observed. The position of the planar optical fiber 8 is adjusted until the current value no longer increases. After adjusting the position of the planar optical fiber 8, it is fixed to the heat sink with UV adhesive and pre-cured using a UV lamp. After pre-curing, the vertically coupled encapsulation structure 100 is removed from the coupling stage and placed in a UV oven for further curing to prevent the planar optical fiber 8 from shifting. Finally, absorbing material can be applied to the inner wall of the encapsulation structure 100, and the vertically coupled encapsulation structure 100 is placed in a capping machine to complete the capping.

[0055] In summary, this invention provides a vertically coupled packaging structure for a broadband surface-incident photodetector. While improving coupling efficiency, the ingenious structural design avoids the 90-degree transition of radio frequency signals, thereby enabling high-frequency signal transmission and fully leveraging the superior performance of the surface-incident detector chip. This vertically coupled packaging structure is simple and low-cost, which is beneficial for promoting the development of optoelectronic chip integrated packaging.

[0056] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A vertically coupled packaging structure, characterized in that, include: The heat sink comprises a first surface and a second surface that are perpendicular to each other. A detector chip is disposed on the first surface, and a photosensitive surface is formed on the detector chip, the photosensitive surface being parallel to the first surface; A radio frequency transmission line is disposed on the first surface and located on the first side of the detector chip, and the radio frequency transmission line is electrically connected to the photosensitive surface. A DC-DC adapter board is disposed on the first surface and located on the second side of the detector chip, the second side being opposite to the first side, and the DC-DC adapter board is electrically connected to the photosensitive surface; A planar optical fiber is disposed on the second surface, with the light outlet of the planar optical fiber facing the photosensitive surface.

2. The vertically coupled packaging structure according to claim 1, characterized in that, The center of the projection of the planar optical fiber onto the first surface coincides with the center of the photosensitive surface.

3. The vertically coupled packaging structure according to claim 1, characterized in that, The long axis of the detector chip and the long axis of the radio frequency line are both parallel to the second surface.

4. The vertically coupled packaging structure according to claim 1, characterized in that, The DC adapter board has a positive electrode portion and a ground electrode portion. The ground electrode portion is treated with a via, and the positive electrode portion is treated with a side semi-encapsulated metallization.

5. The vertically coupled packaging structure according to claim 1, characterized in that, Also includes: A first capacitor is disposed on the first surface and located between the first side and the second side. The input terminal of the first capacitor is connected to the DC adapter board, and the output terminal of the first capacitor is connected to the DC pad of the detector chip. The first capacitor is used to filter the voltage signal transmitted from the DC adapter board to the detector chip.

6. The vertically coupled packaging structure according to claim 1, characterized in that, Also includes: The second capacitor is coupled to the DC adapter board and is used to stabilize the bias voltage generated by the DC adapter board.

7. The vertically coupled packaging structure according to claim 1, characterized in that, Also includes: The metal tube shell includes a first tube wall, a second tube wall, and a third tube wall. The first tube wall is parallel to the third tube wall, and the second tube wall is perpendicularly connected between the first tube wall and the third tube wall. The heat sink is disposed in the cavity formed by the first tube wall, the second tube wall, and the third tube wall. The first tube wall is opposite to the first surface.

8. The vertically coupled packaging structure according to claim 7, characterized in that, A first through hole is formed on the first tube wall, and a DC pin is provided in the first through hole. The DC pin is connected to the input terminal of the DC adapter board through a gold wire. A second through hole is formed on the second tube wall, and the planar optical fiber passes through the second through hole and is disposed on the second surface; A third through hole is formed on the third tube wall, and an RF feedout component is provided in the third through hole. The RF feedout component is connected to the output end of the RF transmission line.

9. A method for fabricating a vertically coupled packaging structure as described in any one of claims 1-8, characterized in that, include: A DC-DC converter board, a detector chip, and an RF transmission line are sequentially mounted on the first surface of the heat sink, with the DC-DC converter board and the RF transmission line located on opposite sides of the detector chip. The output terminal of the DC adapter board is electrically connected to the input terminal of the detector chip, and the output terminal of the detector chip is electrically connected to the output terminal of the radio frequency transmission line. The planar optical fiber is fixed on the second surface of the heat sink, so that the light outlet of the planar optical fiber is facing the photosensitive surface of the detector chip, and the first surface and the second surface are perpendicular to each other.

10. The preparation method according to claim 9, characterized in that, The step of fixing the planar optical fiber to the second surface of the heat sink includes: The distance between the light outlet and the photosensitive surface is adjusted to determine the target position of the planar optical fiber on the second surface. The planar optical fiber is fixed at the target position.

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