Co-sealed device for optical vertical coupling of electro-optical modulation chip and control chip

Abstract

The present invention discloses a co-sealed device for an electro-optical modulation chip and a control chip for optical vertical coupling, comprising: an input optical fiber, an electro-optical modulation chip, an output optical fiber, a monitoring photodetector, a base, a control chip, and a tube shell; a top cavity and an inner cavity are sequentially arranged on the base along an axis from top to bottom; a plurality of heat dissipation channels are provided on the base below the inner cavity; a control chip is bonded in the inner cavity; an electro-optical modulation chip is bonded in the top cavity; a monitoring photodetector is bonded to the top of the electro-optical modulation chip; a tube shell is welded to the top of the base; an input optical fiber and an output optical fiber are welded to the tube shell; input light from the input optical fiber is vertically incident on the input grating coupling port of the electro-optical modulation chip, and output light from the output grating coupling port of the electro-optical modulation chip is vertically incident on the output optical fiber. The co-sealed device for the electro-optical modulation chip and the control chip for optical vertical coupling of the present application has high integration, small size, and the ability to be welded and integrated with microwave circuits.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic hybrid integrated packaging, and in particular to a co-sealing device for an electro-optical modulation chip and a control chip for optical vertical coupling. Background Art

[0002] As electronic information systems evolve toward highly integrated, high-frequency, and broadband technologies, microwave photonics technology is playing an increasingly important role due to its high-frequency, broadband performance. Electro-optical modulators (EOMs), devices that achieve electro-optical conversion, are a crucial link between microwaves and lightwaves. Therefore, developing a highly integrated EOM compatible with the interface of highly integrated microwave circuits is particularly important.

[0003] To overcome the size limitations of RF connectors, currently highly integrated microwave circuits often utilize surface-mounted microwave components on printed circuit boards (PCBs), further increasing the integration level of microwave systems. Currently, electro-optical modulators (EO modulators) are relatively large, making them difficult to integrate with microwave circuits for two main reasons. First, the EO modulator's bias operating point drifts slowly with environmental factors such as temperature, necessitating an external control loop for closed-loop control. This control loop includes discrete components such as optical beam splitters, monitoring photodetectors, and control circuits. These discrete components are packaged independently, resulting in a large overall control loop. Second, the EO modulator's RF interface uses SMA, SMP, or SSMP connectors, which are relatively large. These connectors require corresponding RF connectors for connection to PCBs, increasing the overall size of the microwave system. Co-packaging the EO modulator chip and bias control chip is an effective way to reduce the size of the EO modulator, but direct co-packaging also presents heat dissipation issues for the control chip.

[0004] Therefore, it is particularly important to propose a co-sealed device for an electro-optical modulation chip and a control chip that can be directly soldered to a printed circuit board and has a heat dissipation channel. Summary of the Invention

[0005] In order to solve the technical problems existing in the background technology, the present invention proposes a co-sealed device of an electro-optical modulation chip and a control chip with optical vertical coupling.

[0006] The present invention proposes a co-sealed device for an electro-optical modulation chip and a control chip for optical vertical coupling, comprising: an input optical fiber, an electro-optical modulation chip, an output optical fiber, a monitoring photodetector, a base, a control chip, and a tube shell. The base is provided with a top cavity and an inner cavity along an axis from top to bottom. Multiple heat dissipation channels are provided on the base below the inner cavity. The control chip is bonded in the inner cavity, the electro-optical modulation chip is bonded in the top cavity, and the monitoring photodetector is bonded to the top of the electro-optical modulation chip. The tube shell is welded to the top of the base, and the input optical fiber and the output optical fiber are welded to the tube shell. Input light from the input optical fiber is vertically incident on the input grating coupling port of the electro-optical modulation chip, and output light from the output grating coupling port of the electro-optical modulation chip is vertically incident on the output optical fiber. The electro-optical modulation chip is electrically connected to the control chip, and the monitoring photodetector is electrically connected to the control chip, thereby realizing a bias control closed loop for the electro-optical modulation chip.

[0007] Preferably, a plurality of first metal vias and a plurality of second metal vias are provided inside the base, a plurality of bottom solder balls are provided at the bottom of the base, one first metal via is connected to a bottom solder ball in a one-to-one correspondence, and internal wiring is connected between the ends of the two second metal vias.

[0008] Preferably, the interface of the electro-optical modulation chip includes an input grating coupling port, an output grating coupling port, a monitoring grating coupling port, a radio frequency input port and a bias input port; the radio frequency input port of the electro-optical modulation chip is connected to the base lead through a first metal via, and the external radio frequency signal is fed through the bottom solder ball of the base, and then transmitted to the radio frequency input port of the electro-optical modulation chip through the first metal via corresponding to the bottom solder ball; the bias input port of the electro-optical modulation chip is electrically connected to the bias output port of the control chip through the second metal via of the base and the internal wiring; the input grating coupling port, the output grating coupling port and the monitoring grating coupling port are arrayed waveguide gratings, which are used for vertical coupling of optical transmission between the electro-optical modulation chip and the input light, output light and monitoring light; the radio frequency input port is an radio frequency signal loading port, and the bias input port is a bias voltage loading port.

[0009] Preferably, the monitoring photodetector interface includes a monitoring optical port and a monitoring output port; the monitoring optical port is located on the lower surface of the monitoring photodetector, and the monitoring output port is located on the upper surface of the monitoring photodetector; the monitoring optical port of the monitoring photodetector is arranged to overlap with the monitoring grating coupling port of the electro-optical modulation chip, the monitoring output port of the monitoring photodetector is bonded to the base lead, and the monitoring output port of the monitoring photodetector is electrically connected to the monitoring input port of the control chip through a second metal via and internal wiring.

[0010] Preferably, the interface of the control chip includes a monitoring input port, a bias output port, a download input port, and a status output port. The monitoring input port of the control chip is electrically connected to the monitoring output port of the monitoring photodetector through a second metal via and internal wiring; the bias output port of the control chip is electrically connected to the bias input port of the electro-optical modulation chip through a second metal via and internal wiring; the status output port outputs the status signal of the control chip through the bottom solder ball corresponding to the first metal via; the control program update and download of the control chip are fed in through the bottom solder ball, and then transmitted to the download input port through the first metal via corresponding to the bottom solder ball.

[0011] Preferably, the input optical fiber and the output optical fiber are welded to the top of the tube shell, and the welding strip welds the upper surface of the base to the tube shell to form a closed cavity.

[0012] Preferably, the upper surface of the electro-optical modulation chip is flush with the upper surface of the top cavity.

[0013] The proposed device for co-encapsulating an electro-optical modulator chip and a control chip for vertical optical coupling employs a co-packaged electro-optical modulator chip, a monitoring photodetector, and a control chip. The monitoring photodetector is surface-mounted on the electro-optical modulator chip for optical transmission. The electro-optical modulator chip, monitoring photodetector, and control chip are wire-bonded to metal vias within the base, completing the bias control loop for the electro-optical modulator chip. The base utilizes a vertical multi-cavity design to co-encapsulate the electro-optical modulator chip and the control chip within the base, resulting in a compact device. A heat dissipation channel is provided below the control chip on the base to dissipate heat from the control chip, improving its heat dissipation capacity. The grating coupling port on the electro-optical modulator chip provides vertical optical input and output, avoiding horizontal optical coupling. This further reduces the device's horizontal size and enhances its horizontal expansion capability. Signals such as the electro-optical modulator chip's RF signal, the control chip's download signal, and the control chip's status signal are transmitted via solder balls on the base's bottom surface, connecting to an external printed circuit board. This avoids the need for RF connectors, miniaturizing the device and enabling integration with microwave circuits. The base features a top cavity, within which the electro-optical modulator chip is mounted. The top surface of the chip is flush with the top surface of the base cavity, minimizing the wire bonding distance between the modulator chip's RF port and the base's metal vias, thereby improving the chip's high-frequency performance. The control chip is housed within the base cavity, and the upper portion of the base is hermetically sealed in a tube shell. All chips in the entire device are hermetically sealed, ensuring high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic front cross-sectional view of the co-sealed device of the electro-optical modulation chip and the control chip for optical vertical coupling proposed by the present invention;

[0015] Figure 2This is a schematic top view of the electro-optical modulation chip structure of the optical vertically coupled electro-optical modulation chip and control chip co-sealed device proposed by the present invention;

[0016] Figure 3 This is a schematic diagram of the base of the co-sealed device for the vertically coupled electro-optical modulation chip and control chip proposed by the present invention;

[0017] Figure 4 This is a schematic top view of the control chip structure of the optical vertically coupled electro-optical modulation chip and control chip co-sealed device proposed by the present invention.

[0018] Legend:

[0019] 1. Input optical fiber; 2. Electro-optical modulation chip; 21. Input grating coupling port; 22. RF input port; 23. Bias input port; 24. Output grating coupling port; 25. Monitoring grating coupling port; 3. Output optical fiber; 4. Monitoring photodetector; 5. Base; 51. Base body; 52. Top cavity; 53. Inner cavity; 54. Bottom solder ball; 55. Heat dissipation channel; 561. First metal via; 562. Second metal via; 57. Internal wiring; 58. Soldering strip; 6. Control chip; 61. Monitoring input port; 62. Bias output port; 63. Download input port; 64. Status output port; 7. Tube shell. DETAILED DESCRIPTION

[0020] Reference Figure 1-4 The present invention proposes a co-sealed device for an electro-optical modulation chip and a control chip for optical vertical coupling, comprising: an input optical fiber 1, an electro-optical modulation chip 2, an output optical fiber 3, a monitoring photodetector 4, a base 5, a control chip 6, and a tube shell 7. The base 5 is provided with a top cavity 52 and an inner cavity 53 along an axis from top to bottom. The base 5 is provided with multiple groups of heat dissipation channels 55 below the inner cavity 53. The control chip 6 is bonded in the inner cavity 53, the electro-optical modulation chip 2 is bonded in the top cavity 52, and the top of the electro-optical modulation chip 2 is bonded with the monitoring photodetector 4. The top of the base 5 is welded to the tube shell 7, and the input optical fiber 1 and the output optical fiber 3 are welded to the tube shell 7. The input light of the input optical fiber 1 is vertically incident on the input grating coupling port 21 of the electro-optical modulation chip 2, and the output light of the output grating coupling port 24 of the electro-optical modulation chip 2 is vertically incident on the output optical fiber 3. The electro-optical modulation chip 2 is electrically connected to the control chip 6, and the monitoring photodetector 4 is electrically connected to the control chip 6, so as to realize a bias control closed loop of the electro-optical modulation chip 2.

[0021] In this embodiment, the input optical fiber 1 and the output optical fiber 3 are welded to the tube shell 7 for airtight packaging.

[0022] In this embodiment, a plurality of first metal vias 561 and a plurality of second metal vias 562 are provided inside the base 5, and a plurality of bottom solder balls 54 are provided at the bottom of the base 5. One first metal via 561 is connected to one bottom solder ball 54 in a one-to-one correspondence, and an internal wiring 57 is connected between the ends of the two second metal vias 562.

[0023] In this embodiment, the base body 51 of the base 5 can be composed of high-temperature co-fired ceramics, low-temperature co-fired ceramics, a composite dielectric substrate or a combination thereof, and the first metal via 561, the second metal via 562, and the internal wiring 57 are arranged inside the base body 51.

[0024] In this embodiment, if Figure 2 As shown, the interface of the electro-optical modulation chip 2 includes an input grating coupling port 21, an output grating coupling port 24, a monitoring grating coupling port 25, a RF input port 22, and a bias input port 23; the RF input port 22 of the electro-optical modulation chip 2 is wire-bonded to the base 5 through a first metal via 561, and an external RF signal is fed through the bottom solder ball 54 of the base 5 and then transmitted to the RF input port 22 of the electro-optical modulation chip 2 through the first metal via 561 corresponding to the bottom solder ball 54; the bias input port 23 of the electro-optical modulation chip 2 is electrically connected to the bias output port 62 of the control chip 6 through a second metal via 562 of the base 5 and an internal wiring 57; the input grating coupling port 21, the output grating coupling port 24, and the monitoring grating coupling port 25 are arrayed waveguide gratings, which are used for vertical coupling of optical transmission between the electro-optical modulation chip 2 and the input light, output light, and monitoring light; the RF input port 22 is an RF signal loading port, and the bias input port 23 is a bias voltage loading port. The upper surface of the electro-optical modulation chip 2 is flush with the upper surface of the top cavity 52 .

[0025] In this embodiment, the interface of the monitoring photodetector 4 includes a monitoring optical port and a monitoring output port; the monitoring optical port is located on the lower surface of the monitoring photodetector 4, and the monitoring output port is located on the upper surface of the monitoring photodetector 4; the monitoring optical port of the monitoring photodetector 4 is arranged to overlap with the monitoring grating coupling port 25 of the electro-optical modulation chip 2, and the monitoring output port of the monitoring photodetector 4 is wire-bonded to the base 5, and the monitoring output port of the monitoring photodetector 4 is electrically connected to the monitoring input port 61 of the control chip 6 through the second metal via 562 and the internal wiring 57.

[0026] In this embodiment, if Figure 4As shown, the interface of the control chip 6 includes a monitoring input port 61, a bias output port 62, a download input port 63, and a status output port 64. The monitoring input port 61 of the control chip 6 is electrically connected to the monitoring output port of the monitoring photodetector 4 through the second metal via 562 and the internal wiring 57; the bias output port 62 of the control chip 6 is electrically connected to the bias input port 23 of the electro-optical modulation chip 2 through the second metal via 562 and the internal wiring 57; the status output port 64 outputs the status signal of the control chip 6 through the bottom solder ball 54 corresponding to the first metal via 561; the control program update and download of the control chip 6 are fed in through the bottom solder ball 54, and then transmitted to the download input port 63 through the first metal via 561 corresponding to the bottom solder ball 54.

[0027] In this embodiment, the control chip 6 may be a single-chip processing chip, or a chip combining a single-chip processing chip, an operational amplifier, and a driving amplifier.

[0028] In this embodiment, the input optical fiber 1 and the output optical fiber 3 are welded to the top of the tube shell 7, and the upper surface of the base 5 is welded to the tube shell 7 through a welding strip 58 to form a closed cavity.

[0029] During the specific operation of the optical vertically coupled electro-optical modulation chip and control chip co-sealed device of this embodiment, an optical signal from input fiber 1 is split into two paths within the modulator via the input grating coupling port 21 of the input electro-optical modulation chip 2. The two optical signals undergo electro-optical conversion via the RF input port 22 of the electro-optical modulation chip 2. After the two optical fields become coherent, they are split into two output paths. One path is coupled into the output fiber 3 via the output grating coupling port 24 of the electro-optical modulation chip 2 for modulated optical signal output. The other path, loaded with an RF signal, is converted into an electrical signal at the monitoring photodetector 4 via the monitoring grating coupling port 25 of the electro-optical modulation chip 2. By controlling the bias voltage of the electro-optical modulation chip 2, the electro-optical modulation chip 2 can be adjusted to different bias operating points, such as the quadrature operating point (Quad+, Quad-), the maximum output point (Peak), and the minimum output point (NULL). Due to the inherent characteristics of the electro-optic modulator chip 2, its operating point slowly drifts with changes in environmental factors such as temperature, causing system indicators such as output optical power and RF signal modulation efficiency to also drift slowly. In actual use, the control chip 6 is required to collect the monitoring signal output by the monitoring photodetector 4, compare the monitoring signal with the bias operating point setting, and adjust the voltage at the bias output port 62 of the control chip 6 based on the comparison result, forming a closed-loop control loop to ensure that the bias operating point of the electro-optic modulator chip 2 is consistent with the program setting. Common methods for controlling the bias operating point of the electro-optic modulator chip 2 include bias control methods based on scrambling signal monitoring and bias control methods based on output light intensity monitoring. Control program updates and downloads of the control chip 6 are fed through the bottom solder ball 54 of the base 5 and then transmitted to the download input port 63 of the control chip 6 through the metal via 56 of the base 5. The status output port 64 of the control chip 6 is connected to the bottom solder ball 54 of the base 5 through the first metal via 561 of the base 5 to output the status signal of the control chip 6.

[0030] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A co-sealed device for an electro-optical modulation chip and a control chip with vertical optical coupling, characterized in that: include: An input optical fiber (1), an electro-optical modulation chip (2), an output optical fiber (3), a monitoring photodetector (4), a base (5), a control chip (6), and a tube shell (7); a top cavity (52) and an inner cavity (53) are sequentially provided on the base (5) along an axis from top to bottom; a plurality of heat dissipation channels (55) are provided on the base (5) below the inner cavity (53); a control chip (6) is bonded in the inner cavity (53); an electro-optical modulation chip (2) is bonded in the top cavity (52); and a monitoring photodetector (4) is bonded on the top of the electro-optical modulation chip (2). A tube shell (7) is welded on the top of the base (5), and an input optical fiber (1) and an output optical fiber (3) are welded on the tube shell (7); input light of the input optical fiber (1) is vertically incident on the input grating coupling port (21) of the electro-optical modulation chip (2), and output light of the output grating coupling port (24) of the electro-optical modulation chip (2) is vertically incident on the output optical fiber (3); the electro-optical modulation chip (2) is electrically connected to the control chip (6), and the monitoring photodetector (4) is electrically connected to the control chip (6) to realize a bias control closed loop of the electro-optical modulation chip (2).

2. The optical vertically coupled electro-optical modulation chip and control chip co-sealed device according to claim 1, characterized in that: A plurality of first metal vias (561) and a plurality of second metal vias (562) are provided inside the base (5); a plurality of bottom solder balls (54) are provided at the bottom of the base (5); one first metal via (561) is connected to one bottom solder ball (54) in a one-to-one correspondence; and an internal wiring (57) is connected between the ends of two second metal vias (562).

3. The optical vertically coupled electro-optical modulation chip and control chip co-sealed device according to claim 2, characterized in that: The interface of the electro-optical modulation chip (2) includes an input grating coupling port (21), an output grating coupling port (24), a monitoring grating coupling port (25), a radio frequency input port (22), and a bias input port (23); the radio frequency input port (22) of the electro-optical modulation chip (2) is wire-bonded to the base (5) through a first metal via (561); an external radio frequency signal is fed in through a bottom solder ball (54) of the base (5), and then transmitted to the radio frequency input port (22) of the electro-optical modulation chip (2) through the first metal via (561) corresponding to the bottom solder ball (54). ); the bias input port (23) of the electro-optical modulation chip (2) is electrically connected to the bias output port (62) of the control chip (6) through the second metal via (562) of the base (5) and the internal wiring (57); the input grating coupling port (21), the output grating coupling port (24) and the monitoring grating coupling port (25) are arrayed waveguide gratings, which are used for vertical coupling of optical transmission between the electro-optical modulation chip (2) and the input light, the output light and the monitoring light; the radio frequency input port (22) is a radio frequency signal loading port, and the bias input port (23) is a bias voltage loading port.

4. The optical vertically coupled electro-optical modulation chip and control chip co-sealed device according to claim 2, characterized in that: The monitoring photoelectric detector (4) interface includes a monitoring optical port and a monitoring output port; the monitoring optical port is located on the lower surface of the monitoring photoelectric detector (4), and the monitoring output port is located on the upper surface of the monitoring photoelectric detector (4); The monitoring optical port of the monitoring photodetector (4) is arranged to overlap with the monitoring grating coupling port (25) of the electro-optical modulation chip (2); the monitoring output port of the monitoring photodetector (4) is connected to the base (5) by wire bonding; and the monitoring output port of the monitoring photodetector (4) is electrically connected to the monitoring input port (61) of the control chip (6) through a second metal via (562) and internal wiring (57).

5. The optical vertically coupled electro-optical modulation chip and control chip co-sealed device according to claim 2, characterized in that: The interface of the control chip (6) includes a monitoring input port (61), a bias output port (62), a download input port (63), and a status output port (64). The monitoring input port (61) of the control chip (6) is electrically connected to the monitoring output port of the monitoring photodetector (4) through a second metal via (562) and an internal wiring (57); the bias output port (62) of the control chip (6) is electrically connected to the bias input port (23) of the electro-optical modulation chip (2) through a second metal via (562) and an internal wiring (57); the status output port (64) outputs the status signal of the control chip (6) through a bottom solder ball (54) corresponding to the first metal via (561); the control program update and download of the control chip (6) is fed in through the bottom solder ball (54), and then transmitted to the download input port (63) through the first metal via (561) corresponding to the bottom solder ball (54).

6. The optical vertically coupled electro-optical modulation chip and control chip co-sealed device according to claim 1, characterized in that: The input optical fiber (1) and the output optical fiber (3) are welded to the top of the tube shell (7), and the upper surface of the base (5) and the tube shell (7) are welded via a welding strip (58) to form a closed cavity.

7. The optical vertically coupled electro-optical modulation chip and control chip co-sealed device according to claim 1, characterized in that: The upper surface of the electro-optical modulation chip (2) is flush with the upper surface of the top cavity (52).

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