Light vertical coupling electro-optical modulation chip and control chip co-packaging device

Abstract

The invention discloses a light vertical coupling electro-optical modulation chip and control chip co-packaging device which comprises an input optical fiber, an electro-optical modulation chip, an output optical fiber, a monitoring photoelectric detector, a base, a control chip and a tube shell. A top cavity and an inner cavity are sequentially arranged on the base from top to bottom along the axis, a plurality of sets of heat dissipation channels are formed in the position, below the inner cavity, of the base, a control chip adheres to the interior of the inner cavity, an electro-optical modulation chip adheres to the interior of the top cavity, a monitoring photoelectric detector adheres to the top of the electro-optical modulation chip, and a tube shell is welded to the top of the base. An input optical fiber and an output optical fiber are welded on the tube shell; the input light of the input optical fiber is vertically incident to the input grating coupling port of the electro-optical modulation chip, and the output light of the output grating coupling port of the electro-optical modulation chip is vertically incident to the output optical fiber. The light vertical coupling electro-optical modulation chip and control chip co-packaging device is high in integration level and small in size, and has the capability of being welded and integrated with a microwave circuit.

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 of an electro-optical modulation chip and a control chip for optical vertical coupling. Background Art

[0002] As electronic information systems develop towards high-integration, high-frequency and broadband, microwave photonics technology plays an increasingly important role in it due to its high-frequency and broadband performance. Electro-optical modulators are devices that realize electro-optical conversion and are an important link between microwaves and light waves. Therefore, it is particularly important to propose a highly integrated electro-optical modulator that is compatible with the interface of highly integrated microwave circuits.

[0003] In order to avoid the size limitation of RF connectors, the current highly integrated microwave circuits often adopt the form of integrated packaging by mounting microwave components on printed circuit boards, thereby further improving the integration of microwave systems. At present, the electro-optic modulator is large in size and difficult to integrate with microwave circuits. There are two main reasons: on the one hand, the bias operating point of the electro-optic modulator will drift slowly with the change of environmental factors such as temperature, so an external control loop is required for closed-loop control. The control loop includes discrete devices such as optical beam splitters, monitoring photodetectors, and control circuits. These discrete devices have their own independent packages, resulting in a large volume of the entire control loop; on the other hand, the RF interface of the electro-optic modulator is SMA, SMP, SSMP and other interfaces. These interfaces are large in size and require corresponding RF connectors for transfer when connected to printed circuit boards, which will result in a large size of the entire microwave system. Co-packaging the electro-optic modulation chip and the bias control chip is an effective means to reduce the size of the electro-optic modulator, but direct co-packaging also has the problem of heat dissipation of the control chip.

[0004] Therefore, it is particularly important to propose a co-sealing 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 invention provides a device for co-sealing an electro-optical modulation chip and a control chip for vertical optical 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 on the top of the electro-optical modulation chip, a tube shell is welded on the top of the base, and an input optical fiber and an output optical fiber are welded on the tube shell; input light of the input optical fiber is vertically incident on an input grating coupling port of the electro-optical modulation chip, output light of an output grating coupling port of the electro-optical modulation chip is vertically incident on an 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, so as to realize a bias control closed loop of the electro-optical modulation chip.

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

[0008] Preferably, the interface of the electro-optic 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-optic modulation chip is connected to the base lead by bonding through a first metal via, and an external radio frequency signal is fed through a bottom solder ball of the base, and then transmitted to the radio frequency input port of the electro-optic modulation chip through a first metal via corresponding to the bottom solder ball; the bias input port of the electro-optic modulation chip is electrically connected to the bias output port of the control chip through a second metal via of the base and 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-optic modulation chip and the input light, output light and monitoring light, the radio frequency input port is a 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 wire-bonded to the base, 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-optic modulation chip is flush with the upper surface of the top cavity.

[0013] In the present invention, the proposed optical vertically coupled electro-optical modulation chip and control chip co-sealed device, by co-sealing the electro-optical modulation chip, monitoring photodetector and control chip, the surface of the electro-optical modulation chip is mounted with the monitoring photodetector for optical path transmission, the electro-optical modulation chip, the monitoring photodetector and the control chip are connected by wire bonding with metal vias in the base to achieve circuit connection, and the bias control closed loop of the entire electro-optical modulation chip is completed. The base co-seales the electro-optical modulator chip and the control chip in the base through a vertical multi-cavity design, and the size of the entire device is small. A heat dissipation channel is set below the control chip on the base to dissipate heat for the control chip, thereby improving the heat dissipation capacity of the control chip. The grating coupling port on the electro-optical modulation chip performs optical vertical input and output to avoid horizontal optical coupling, which can further reduce the horizontal size of the entire device and improve the horizontal expansion capacity. The electro-optical modulation chip radio frequency signal, the control chip download signal, the control chip status signal and other signal transmission are performed by welding the solder ball at the bottom of the base to the external printed circuit board, avoiding the transfer of the radio frequency connector, and the size of the entire device can be reduced, and it has the ability to be welded and integrated with the microwave circuit. The base has a top cavity at the top, and the electro-optical modulation chip is mounted in the top cavity. The upper surface of the electro-optical modulation chip is flush with the upper surface of the base top cavity, which reduces the bonding distance between the modulator chip RF port and the base metal via lead, and improves the high-frequency performance of the electro-optical modulation chip. The control chip is placed in the inner cavity of the base, and the upper part of the base is sealed by a tube shell. All chips in the entire device are sealed and packaged, with high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0016] Figure 3 It is a schematic diagram of the base of the co-sealed device of the electro-optic modulation chip and the control chip for vertical optical coupling 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-optic 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 belt; 6. Control chip; 61. Monitoring input port; 62. Bias output port; 63. Download input port; 64. Status output port; 7. Shell and tube. DETAILED DESCRIPTION

[0020] Reference Figure 1-4 The present invention proposes a device for co-sealing an electro-optical modulation chip and a control chip for vertical optical 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; a top cavity 52 and an inner cavity 53 are sequentially arranged on the base 5 along the 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, 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, 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, a plurality of bottom solder balls 54 are provided at the bottom of the base 5, one first metal via 561 is connected to a 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-optic 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-optic modulation chip 2 is connected to the base 5 by wire bonding through the first metal via 561, and the external radio frequency signal is fed through the bottom solder ball 54 of the base 5, and then transmitted to the radio frequency input port 22 of the electro-optic modulation chip 2 through the first metal via 561 corresponding to the bottom solder ball 54; the bias input port 23 of the electro-optic 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-optic 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. The upper surface of the electro-optic 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, 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] In the specific working process of the optical vertically coupled electro-optical modulation chip and control chip co-sealed device of this embodiment, the input optical signal of the input optical fiber 1 is divided into two paths in the modulator through the input grating coupling port 21 of the input electro-optical modulation chip 2, and the two optical signals are electro-optically converted through the radio frequency input port 22 of the electro-optical modulation chip 2. After the two optical fields are coherent, they are divided into two outputs, one of which is coupled into the output optical fiber 3 through the output grating coupling port 24 of the electro-optical modulation chip 2 to output the modulated optical signal, and the other optical signal loaded with the radio frequency signal is converted into an electrical signal output on the monitoring photodetector 4 through the monitoring grating coupling port 25 of the electro-optical modulation chip 2. By controlling the bias voltage of the electro-optical modulator chip 2, the electro-optical modulation chip 2 can be adjusted to different bias working points such as the orthogonal working point (Quad+, Quad-), the maximum output point (Peak), the minimum output point (NULL), etc. Due to the characteristics of the electro-optic modulator chip 2, the working point of the electro-optic modulator chip 2 will slowly drift with the change of environmental factors such as temperature, resulting in the system indicators such as output optical power and RF signal modulation efficiency also drifting slowly. In actual use, it is necessary to collect the monitoring signal output by the monitoring photodetector 4 through the control chip 6, compare the monitoring signal with the bias working point setting value, and adjust the voltage of the bias output port 62 of the control chip 6 according to the comparison result to form a closed-loop control, so as to achieve the bias working point of the electro-optic modulator chip 2 consistent with the program setting value. Commonly used electro-optic modulator chip 2 bias working point control methods include bias control methods based on jamming signal monitoring and bias control methods based on output light intensity monitoring. The control program update and download of the control chip 6 are fed in 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 state 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, and the state signal of the control chip 6 is output.

[0030] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for co-sealing an electro-optical modulation chip and a control chip for optical vertical 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 arranged on the base (5) along the axis from top to bottom; a plurality of heat dissipation channels (55) are arranged 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-optic modulation chip (2), and output light of the output grating coupling port (24) of the electro-optic modulation chip (2) is vertically incident on the output optical fiber (3); the electro-optic 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-optic 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 arranged inside the base (5); a plurality of bottom solder balls (54) are arranged at the bottom of the base (5); one first metal via (561) is connected to a 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-optic modulation chip (2) comprises 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-optic modulation chip (2) is wire-bonded to the base (5) via a first metal via (561); an external radio frequency signal is fed in via a bottom solder ball (54) of the base (5), and then transmitted to the radio frequency input port (22) of the electro-optic modulation chip (2) via the first metal via (561) corresponding to the bottom solder ball (54). ); the bias input port (23) of the electro-optic 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-optic 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 the second metal via (562) and the 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) comprises 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-optic 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 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-optic modulation chip (2) is flush with the upper surface of the top cavity (52).

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