JP4951971B2 - Photoelectric composite module - Google Patents

Description

  The present invention relates to a photoelectric composite module, and more particularly to a high-speed photoelectric composite module on which a light emitting element, a driver IC, and the like are mounted.

  In recent years, high-speed, low-cost, and small-sized optical transceivers are expected to be realized in optical communications such as regional networks and intercity networks, and optical links within and between servers and routers. Yes. In addition, the standardization of 10 Gbit / s Ethernet (registered trademark) has progressed, and a configuration is required in which the front end of the optical input / output unit is narrow so that the optical transceiver can be miniaturized, in particular, the interface density of the device can be increased. It has been. The optical transceiver is composed of an optical transmitter and an optical receiver. Among them, the module of the optical transmitter has a drive LSI, a light emitting element such as a semiconductor laser, and an optical monitor element such as a photodiode.

  Until now, this type of surface-mount type opto-electric composite module has formed an optical coupling system such as an optical monitor element, light emitting element, lens, and optical fiber from the viewpoint of not increasing optical coupling loss, and a drive LSI is provided outside the optical coupling system Had been placed. FIG. 7 shows a schematic diagram of a conventional photoelectric composite module. FIG. 7A is a schematic cross-sectional view, and FIG. 7B is a schematic top view. The light emitting element 101 is mounted on the heat radiating substrate 141, the lens 152 is disposed close to the output side of the light emitting element 101, and the light monitoring element 102 is disposed close to the opposite side, and is mounted on the wiring substrate 143 formed on the ceramic package. The drive LSI 103 is disposed further behind the optical monitor element 102.

  On the other hand, from the viewpoint of speeding up, a photoelectric composite module having a structure in which a driving LSI and a light emitting element are arranged close to each other is also disclosed. In one disclosed example, a light emitting element and a driving LSI are brought close to each other, the driving LSI is connected to the outside via a high-speed line on a wiring board, and a wire for electrical connection is shortened. The optical monitor element is arranged on a mounting member on the wiring board, and the monitor light emitted from the side opposite to the output side of the light emitting element passes through the drive LSI and is coupled to the optical monitor element (for example, (See Patent Document 1).

  Also disclosed is a technique in which one of an optical monitoring element and a light emitting diode (LD) driving IC is disposed close to the light emitting element (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 2002-252407 (page 4-6, FIGS. 2 and 3) JP 2003-232967 A

  However, if priority is given to the optimal arrangement of the optical coupling system as shown in FIG. 7, the distance of the wire from the driving LSI to the light emitting element becomes long, so that a high-speed signal of 10 Gbit / s level is transmitted without being affected by loss or reflection. That was difficult.

  Further, as shown in Patent Document 1, when priority is given to high-speed operation, it is necessary to bring the light emitting element and the driving LSI close to each other, and conversely, the distance between the light emitting element and the light monitoring element increases. Since the monitor light from the light emitting element has a beam spread, if the distance is increased, the coupling loss between the light emitting element and the optical monitor element increases, and the power level of the monitor light falls below the allowable reception range of the optical monitor element. There was a problem.

  As described above, in the prior art, the optimal arrangement of the light emitting element, the optical monitor element, the lens, etc. for suppressing the increase in loss of the optical coupling system cannot be compatible with the close arrangement of the driving LSI and the light emitting element for high-speed operation. There was a problem.

  Further, Patent Document 2 shows a structure in which either the light monitoring element or the LD driving IC is disposed close to the light emitting element. However, it is difficult to place both of them close to each other at the same time. Is difficult to solve. In addition, the waveguide layer is formed on the insulating layer, but the electrical wiring on the waveguide is only connected to the lead, and the ground necessary for stably realizing high-speed transmission of 10 Gbit / s level. It is difficult to arrange the electrodes. Furthermore, the preamplifier on the waveguide is connected on the assumption of a relatively long wire capable of transmitting 1 Gbit / s level, and there is a difficulty in realizing high-speed transmission that requires 1 mm or less.

  In view of the above circumstances, an object of the present invention is to provide an opto-electric composite module that achieves both an optimal arrangement capable of suppressing an increase in loss of an optical coupling system and a close arrangement of a driving LSI and a light emitting element capable of high-speed operation. It is to provide.

In order to achieve the above object, a photoelectric composite module according to the present invention is installed on a heat dissipation substrate, generates a light signal, an optical signal output surface of the light emitting device, and a surface opposite to the output surface. An optical waveguide for transmitting the optical signal generated by the light emitting element, facing the at least one of the light emitting element, an insulating layer provided in the heat dissipation substrate and incorporating the optical waveguide, and flip-chip mounted on an upper surface of the insulating layer A driving LSI for supplying a current amplification signal to the light emitting element; an optical monitoring element installed on the heat dissipation substrate for monitoring light emission of the light emitting element; and a monitor signal for the optical monitoring element is supplied to the driving LSI. A driving line connecting the DC line, the driving LSI and the light emitting element in the thickness direction of the insulating layer; and an upper surface of the insulating layer in contact with the driving LSI; Anda electrical input transmission line supplies the electrical input signal,
The transmission line for electrical input is
An upper ground line extending in contact with the driving LSI and extending from the upper surface of the insulating layer; a lower ground line extending from the upper surface of the heat dissipation substrate; and a ground electrode connecting portion connecting the upper ground line and the lower ground line. It is characterized by having .

  As a result, the electrical wiring and the optical wiring can be three-dimensionally configured, and the optical waveguide, the light emitting element, and the optical monitoring element can be combined, and the light emitting element and the driving LSI can be arranged close to each other. It is possible to transmit a high-speed signal of 10 Gbit / s level while suppressing deterioration due to loss and reflection.

A light emitting element and an optical monitoring element are disposed on a heat dissipation substrate, and an optical waveguide that is optically coupled to the light emitting element is provided in an insulating layer and disposed on the heat dissipation substrate, whereby the light emitting element and the light monitoring element are disposed. And the optical waveguide can be arranged in a positional relationship for suppressing increase in loss of optical coupling. Since various elements of the optical coupling system can be arranged close to each other, the coupling loss of the optical coupling system can be kept low. Therefore, it is possible to transmit a 10 Gbit / s level high-speed signal while suppressing deterioration due to the effects of loss and reflection.

Further, by flip-chip mounting the driving LSI on the upper surface of the insulating layer of the heat dissipation substrate, the driving LSI and the light emitting element can be arranged close to each other, and the insulating layer containing the optical waveguide is provided. Since the DC line, the driving signal line, and the electric input transmission line are wired by use, the line is constructed as a three-dimensional structure, and the distance for transmitting and receiving signals can be extremely shortened.

  Further, the ground electrode connection portion may be a via extending in the vertical direction in the insulating layer at a position where it does not interfere with the optical waveguide.

  The insulating layer may have a coplanar line including the upper ground electrode on the upper surface. The insulating layer may be formed from a polymer resin material.

  Moreover, it is good also as a structure further provided in the guide mechanism on the thermal radiation board | substrate with which the said waveguide type optical element was installed, and connecting with the said optical waveguide and performing light input / output.

  A plurality of the optical waveguides may be formed in an array, and the waveguide type optical element may be connected to each of the optical waveguides.

As described above, according to the present invention, the light emitting element and the light monitoring element are disposed on the heat dissipation substrate, and the optical waveguide that is optically coupled to the light emitting element is embedded in the insulating layer and disposed on the heat dissipation substrate. Thus, the light emitting element, the optical monitoring element, and the optical waveguide can be arranged in a positional relationship for suppressing increase in loss of optical coupling. Since various elements of the optical coupling system can be arranged close to each other, the coupling loss of the optical coupling system can be kept low. Therefore, it is possible to transmit a 10 Gbit / s level high-speed signal while suppressing deterioration due to the effects of loss and reflection.
Furthermore, the drive LSI and the light emitting element can be arranged close to each other by flip-chip mounting the drive LSI on the upper surface of the insulating layer of the heat dissipation substrate.
Furthermore, since the DC line, the drive signal line, and the electrical input transmission line are wired using the insulating layer containing the optical waveguide, the distance for constructing the line as a three-dimensional structure and transmitting and receiving signals Can be very short .

  In addition, since the electrical wiring and the optical wiring have a three-dimensional configuration, the proximity arrangement of the optical coupling system and the proximity arrangement of the light emitting element and the driving LSI can be independently optimized, and the module can be downsized.

  Further, since the optical element and the electric element can be mounted on the same substrate, the number of parts and the number of processes can be reduced and the mounting cost can be suppressed.

In addition, the optical element is installed directly above the heat dissipation board, and the electrical element above the insulating layer is connected to the heat dissipation path that reaches the heat dissipation board via the upper ground electrode, via, and lower lower ground electrode above the resin layer. Therefore, there is no problem in the heat dissipation of the optical element / electric element.

Furthermore, since optical coupling can be performed with reference to an electrode pad and an optical waveguide formed in the platform, there is also an advantage that non-aligned mounting of the optical coupling system is achieved.

  Next, an embodiment of the photoelectric composite module according to the present invention will be described in detail with reference to the drawings. The photoelectric composite module of the present invention can be used, for example, for optical communication typified by a regional network, an intercity network, etc., and an optical link between servers and routers.

  Fig.1 (a) is a schematic sectional drawing which shows the structure of the photoelectric composite module which concerns on this invention. FIG. 1B is a plan view showing the arrangement of components constituting the optoelectric composite module according to the present invention and omitting the wiring relationship. FIG. 2 is a plan view showing the wiring relationship with the drive LSI removed. In the photoelectric composite module 4a according to the present invention, an insulating layer 42 is laminated on a heat dissipation substrate 41, the insulating layer 7 is formed on the insulating layer 42, the light emitting element 1 as a waveguide type optical element, the light monitoring element 2, Various layers and elements such as the driving LSI 3 are provided. An optical fiber 51 is disposed at a predetermined position of the insulating layer 42, and the insulating layer 7, the light emitting element 1, and the optical monitoring element 2 are arranged along the optical axis of the core 51 a of the optical fiber 51.

  The light-emitting element 1 is an edge-emitting element, and has a structure that outputs light from the front end face toward the front (on the optical waveguide 71 side of the insulating layer 7). The light emitting element 1 is mounted on the insulating layer 42 so that the optical signal output portion 1 a is aligned with the height position of the core 51 a of the optical fiber 51. The light emitting element 1 receives the current amplitude signal from the driving LSI 3, generates an optical signal, and outputs the optical signal from the height position of the output unit 1 a toward the core 51 a of the optical fiber 51. The layer structure and the internal structure of the light emitting element 1 are suitable for coupling optical waveguides.

  The insulating layer 7 is disposed between the optical fiber 51 and the light emitting element 1, and brings the insulating layer 7, the light emitting element 1, and the optical fiber 51 close to each other. The insulating layer 7 incorporates an optical waveguide 71, and the optical waveguide 71 is mounted on the insulating layer 42 so as to coincide with the height position of the output portion 1 a of the light emitting element 1 and the height position of the core 51 a of the optical fiber 51. Has been. Therefore, the optical signal output from the light emitting element 1 is directly input from the output portion 1a of the light emitting element 1a to the optical waveguide 71 of the insulating layer 7, and is high from the optical waveguide 71 of the insulating layer 7 to the core 51a of the optical fiber 51. Enter with efficiency. The internal structure of the insulating layer 7 is formed in a refractive index structure suitable for optical waveguide, and an optical waveguide 71 is formed inside the refractive index structure. The insulating layer 7 has characteristics such as low dielectric constant and low dielectric loss in order to realize a high-speed transmission line (described later). Examples of the material of the insulating layer 7 include polymer resin materials. By selecting a polymer resin as the material of the insulating layer 7, it is possible to have both high speed as an electric circuit and light transmission, and therefore, it is suitable as the insulating layer 7. That is, the parasitic capacitance can be reduced by using a thick polymer resin as the material of the insulating layer 7, and the fabrication accuracy of the high-speed transmission line can be relaxed by using a low dielectric constant and low dielectric loss polymer resin. . If a resin having a low loss with respect to the signal wavelength is used, an optical waveguide 71 having a low dielectric loss can be produced in the insulating layer 7.

The driving LSI 3 is flip-chip mounted with bumps 66 on a high-speed signal line ( to be described later) formed on the upper surface of the insulating layer 7. The driving LSI 3 gives a current amplitude signal necessary for driving to the light emitting element 1 in accordance with an external electric signal (modulated signal of a specified voltage), and causes the light emitting element 1 to generate an optical signal. Further, the drive LSI 3 has a function of performing automatic power control (Auto Power Control, APC) by adjusting the current amplitude according to the current value from the optical monitor element 2. The driving LSI 3 does not have to have a function of adjusting the current amplitude with respect to the voltage modulation signal and the APC function, and another LSI may share the APC function.

  The light monitoring element 2 is disposed close to the rear of the light emitting element 1 (surface opposite to the optical waveguide 71), and is mounted on the heat dissipation substrate 41 through the insulating layer 42. The optical monitor element 2 is a waveguide type or surface type photodetector. The optical signal output backward from the light emitting element 1 is received by the light receiving surface 2a, and the received optical signal (monitor light) is converted into a current. To the driving LSI 3. In the example shown in FIG. 1B, the light monitoring element 2 is disposed immediately behind the light emitting element 1, but the present invention is not limited to this. In the optical monitor element 2, the light receiving surface 2 a may be arranged perpendicular to the optical axis of the optical signal in consideration of the beam spread of the optical signal output backward from the light emitting element 1. Furthermore, the light receiving surface 2a of the light monitoring element 2 may be arranged in parallel with the heat dissipation substrate 41 so that the optical signal is received in the region where the beam has spread. The monitor light may be incident from the side surface of the light monitor element 2. These variations are possible because the light emitting element 1 and the light monitoring element 2 are close to each other.

  These elements are connected to each other by a three-dimensional line. Hereinafter, the three-dimensional track will be described with reference to FIGS. As shown in FIG. 2, an L-shaped upper ground line 68 larger than the outer shape of the drive LSI 3 is formed on the upper surface of the insulating layer 7. On the other hand, a lower ground line 65 a is formed in the same L shape as the upper ground line 68 on the lower surface of the insulating layer 7. In this case, the upper ground line 68 is formed with cuts 68a, 68b, 68c at positions intersecting with a high-speed signal line, which will be described later, to avoid contact with the high-speed signal line. The cuts corresponding to the cuts 68a, 68b, and 68c are not formed, and are formed in a continuous L-shape. Further, the upper ground line 68 separated by the notch 68a is connected by a plurality of vias 67 penetrating vertically through the insulating layer 7 while avoiding interference with the optical waveguide 71. With this structure, the upper ground line 68 and the lower ground line 65a can maintain a stable ground. As will be described later, the upper ground line 68 is connected to the drive LSI 3. In this case, since the upper ground line 68 is connected to the lower ground line 65a through the plurality of vias 67, the heat generated by the driving LSI 3 is the upper ground line 68, the plurality of vias 67, and the lower ground line 65a. The heat is transmitted to the heat radiating board 41 through and is dissipated by the heat radiating board 41.

  High-speed signal lines 63 a are formed in two cuts 68 a formed in the upper ground line 68 so as to be separated from the upper ground line 68. A high-speed signal line 63 b is formed in the notch 68 b of the upper ground line 68 so as to be isolated from the upper ground line 68. A DC line 61 is formed in the notch 68 c of the upper ground line 68 so as to be isolated from the upper ground line 68. The high-speed signal lines 63 a and 63 b supply a drive signal to the drive LSI 3, and the high-speed signal line 63 c supplies a drive signal from the drive LSI 3 to the light emitting element 1. The DC line 61 is for supplying a control signal from the optical monitor element 2 to the drive LSI 3.

  As described above, the three-dimensionally structured line forms a coplanar line structure including the high-speed signal lines 63 a, 63 b, 63 c, 61 and the ground line 68 on the same surface on the upper surface of the insulating layer 7. A coplanar line structure including the signal line 62, the DC line 60 and the ground lines 65a, 65b, 65c on the same surface is formed, and these coplanar line structures are connected in the thickness direction of the insulating layer to form a three-dimensional structure. .

  The ground terminal of the driving LSI 3 is connected to the upper ground line 68 by a bump 66, and the signal input terminal of the driving LSI 3 is connected to the high-speed signal lines 63 a and 63 b by a bump 66. A signal output terminal of the driving LSI 3 is connected to the high-speed signal line 63 c by a bump 66, and a control signal input terminal of the driving LSI 3 is connected to the DC line 61 by a bump 66. In this way, the driving LSI 3 is mounted on the insulating layer 7.

  A high-speed signal line 62, a DC line 60, and ground lines 65b and 65c are formed in a region of the insulating layer 42 where the light emitting element 1 and the light monitoring element 2 are mounted. Two vias 69 and 75 are vertically formed in the insulating layer 7 so as to avoid interference with the optical waveguide 71. The via 69 connects the high-speed signal line 62 and the high-speed signal line 63c. The via 75 connects the DC line 61 and the DC line 60.

  The optical monitor element 2 is mounted on the heat dissipation substrate 41 with a ground terminal connected to the ground line 65c and a control signal output terminal connected to the DC line 60 by bumps. The light emitting element 1 is mounted on the heat dissipation substrate 41 with a ground terminal connected to the ground line 65b and a control signal input terminal connected to the high-speed signal line 62 by bumps. A power supply line (not shown) for power supply is connected to the drive LSI. The high-speed signal lines 62, 63a, 63b, and 63c have a characteristic that enables transmission of electrical signals of several Gbit / s to several tens Gbit / s practically.

  In the embodiment described above, the coplanar line structure formed separately in the thickness direction of the insulating layer is connected by the via 69, but the structure connecting the coplanar line structure in the thickness direction of the insulating layer is not limited to the via 69. As shown in FIGS. 3A and 3B, a high-speed signal line 76 is formed on the end face of the insulating layer 7 and the high-speed signal line 63 has a coplanar line structure 63 (63a, 63b). 63c) and the high-speed signal line 62 may be connected. Further, the sharp end face of the insulating layer 7 may be formed obliquely, and the high-speed signal line 76 may be formed on the slope as indicated by a broken line.

  As shown in FIGS. 3C and 3D, the high-speed signal lines 63 and 62 may be connected using a wire 77. In this case, in order to transmit a signal at high speed, it is necessary to make the length of the wire 77 as short as possible. The connection structure shown in FIGS. 3A to 3D may be employed to connect the DC lines 60 and 61.

  The line in the above-described optoelectric composite module 4 has a coplanar line structure including the signal line and the ground line on the insulating layer 7 and the insulating layer 42 on the same plane, but is not limited thereto. A microstrip line structure in which the signal line and the ground line forming each coplanar line structure are sandwiched between insulating layers, and these microstrip structure signal lines may be connected in the thickness direction of the insulating layer to form a three-dimensional structure line. is there.

  Next, the operation of the photoelectric composite module will be described. When an electrical logic signal having a specified voltage and a power supply voltage are supplied to the driving LSI 3 from the outside, a current corresponding to the external electrical signal has a necessary amplitude for driving the light emitting element 1 and is output from the driving LSI 3 as a high-speed signal. It flows to the light emitting element 1 through the line 63, the via 69, and the high-speed signal line 62. The light emitting element 1 emits an optical signal based on the current. An optical signal from the light emitting element 1 is input to the optical waveguide 71, is transmitted to the optical fiber 51 through the optical waveguide 71, and is transmitted to a necessary location by the optical fiber 51.

  On the other hand, when the light monitor element 2 receives light output from the opposite side of the light emitting element 1 as monitor light, the light monitor element 2 outputs a current corresponding to the monitor light. This current flows to the drive LSI 3 via the DC line 60, the via 75, and the DC line 61. The drive LSI 3 adjusts the current amplitude according to the current from the optical monitor element 2 to realize the APC function.

  The specific example of the photoelectric composite module 4a shown in FIG. 1 is shown. A distributed feedback type edge emitting laser having an oscillation wavelength of 1310 nm was used as the light emitting element 1 and a planar photodiode was used as the optical monitoring element 2, and these optical elements were flip-chip mounted on the photoelectric composite module 4a. For the insulating layer 7 of the photoelectric composite module 4a, a polymer resin having an optical waveguide loss of 0.5 dB / cm, a relative dielectric constant of 3, and a dielectric loss tangent of 0.005 was used. The high-speed transmission line was prepared so that the impedance resistance was 50Ω. In the driving LSI 3, the current supplied to the light emitting element 1 is controlled by an electrical signal of 10 Gbit / s differential input from the outside. The wiring length between the driving LSI 3 and the light emitting element 1 became 1 mm or less due to the proximity, and an optical output waveform without deterioration in eye opening characteristics was obtained. On the other hand, the coupling loss between the light emitting element 1 and the light monitoring element 2 was 0.5 dB, and the output current of the light monitoring element 2 at this time was 0.5 mA, and the APC operation was confirmed.

  As described above, the photoelectric composite module 4a of the present embodiment includes the optical system including the optical monitor element 2, the light emitting element 1, the optical waveguide 71, the optical fiber 51, and the like, and the high-speed signal between the driving LSI 3 and the light emitting element 1. The lines 62 and 63 (63a, 63b, and 63c) can be arranged three-dimensionally. For this reason, it is possible to suppress the coupling loss by arranging the coupling system close to each other, and to arrange the driving LSI 3 and the light emitting element 1 close to each other, so that the functions of the high-speed wiring and the optical waveguide can be satisfied at the same time. A high-speed signal of 10 Gbit / s level can be transmitted while suppressing deterioration due to the influence. In addition, since each element can be closest, the photoelectric composite module can be miniaturized. Further, there is an advantage in mounting the optical element and the electric element on the same substrate, and there is an effect that the mounting can be simplified.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a schematic top view of the photoelectric composite module. The present embodiment is different from the first embodiment in that an electric input is input from the rear part of the photoelectric composite module 4b. That is, a high-speed signal line 63a for performing electric input is provided at the rear part of the photoelectric composite module 4b, and an electric signal is directly input to the high-speed signal line 63a. Further, unlike the first embodiment, the DC line 60 is installed on the lower side of the optical waveguide 71 in the drawing. In such an embodiment, for example, a high-speed signal line 63a is inserted into a plug-in type module, and an electric signal is input to the high-speed signal line 63a. Therefore, the electric signal passes through the high-speed signal line 63a having a coplanar line structure. Therefore, the signal is transmitted to the drive LSI 3 with almost no signal deterioration as if it was bonded with a long wire. Such an embodiment has an advantage that it can be effectively applied to, for example, a plug-in type module.

  Next, a third embodiment of the present invention will be described with reference to the drawings. 5A and 5B are configuration diagrams of the photoelectric composite module. FIG. 5A is a schematic sectional view, and FIG. 5B is a schematic top view. The photoelectric composite module 4c of this embodiment is different from the first and second embodiments in that the drive LSI 3 is disposed on the back side of the light emitting element 1. An insulating layer 7 including an optical waveguide 71 is disposed in front of the light emitting element 1, and an optical signal is optically output through the optical waveguide 71 and the optical fiber 51. An insulating layer 7c is disposed behind the light emitting element 1, and an optical waveguide 72 is built in the insulating layer 7c. The optical monitor element 2 is disposed behind the optical waveguide 72. Further, the driving LSI 3 is disposed on the insulating layer 7c. The electrical connection and operation of each element are the same as in the first embodiment. In the first embodiment, the light emitting element 1 and the light monitoring element 2 are optically coupled by direct coupling. However, the present embodiment is characterized in that they are optically coupled via the optical waveguide 72. Thereby, even if the position of the optical monitor element 2 is separated, the optical monitor element 2 can be arranged at a desired position because the optical monitor element 2 is coupled by the optical waveguide 72. In this embodiment, the high-speed signal line 63a is drawn behind the photoelectric composite module 4c as in the second embodiment, and has a configuration effective for, for example, a plug-in type module.

  Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a schematic top view of the photoelectric composite module. The photoelectric composite module 4d according to this embodiment is different from each of the above embodiments in that it is a four-channel array module. A total of four light-emitting elements 1 are provided for each channel, and two light monitoring elements 2 in which two channels are integrated are provided, and each monitor the light of the two light-emitting elements 1. Between each light emitting element 1 and each light monitoring element 2, four optical waveguides 72 similar to those of the third embodiment are provided. Although not shown in the figure, the driving LSI 3 is mounted on the insulating layer 7c and supplies current amplification signals from one driving LSI 3 to the four light emitting elements 1 via the high-speed signal line 63c. It has become.

  In such a photoelectric composite module 4d, the optical waveguide and the electrical wiring can be routed independently, so that further optimization is possible. In this embodiment, since there is no restriction such as the equal length wiring of the optical waveguide 72 and the DC line 61 up to the optical monitor element 2, one end of the optical waveguide 72 can be shifted up and down to be coupled to the optical monitor element 2. is there. This eliminates the need for pitch conversion of the high-speed signal line 63c from the driving LSI 3, and makes it possible to optimize the equal length wiring.

  In addition, when the influence of heat radiation and crosstalk between adjacent ones can be ignored, a plurality of light emitting elements 1 may be brought close to each other to form an array. In addition, the insulating layers 7 and 7c have a configuration in which the portion incorporating the optical waveguide 72 and the portion incorporating the optical waveguide 71 are separated, but these insulating layers 7 and 7c may be integrated. Similar to the third embodiment, the upper ground line 68 may be formed on the insulating layer 7c. Furthermore, although the case of four channels is shown in the present embodiment, the number of channels can be any number of channels.

  As described above, according to the present invention, since the light emitting element and the light monitoring element, and the light emitting element and the driving LSI can be arranged close to each other, the coupling loss of the optical coupling system can be kept low and 10 Gbit / s. It is possible to transmit a high-speed signal of a level with minimal deterioration due to the effects of loss and reflection.

FIG. 1A is a schematic cross-sectional view of the photoelectric composite module according to the first embodiment of the present invention, and FIG. 1B is a plan view. It is explanatory drawing which shows the detail of the connection between each element of the photoelectric composite module shown in FIG. FIGS. 3A and 3B are diagrams showing variations of the connection structure between the light emitting element and the driving LSI of the photoelectric composite module shown in FIG. 1, in which FIG. 3A is a side view, and FIG. FIG. 3C is a side view, and FIG. 3D is a BB arrow view of FIG. 3C. FIG. 4 is a schematic plan view of the photoelectric composite module according to the second embodiment of the present invention. FIG. 5A is a schematic cross-sectional view of a photoelectric composite module according to the third embodiment of the present invention, and FIG. 5B is a schematic plan view. FIG. 6 is a schematic plan view of a photoelectric composite module according to the fourth embodiment of the present invention. FIG. 7A is a schematic cross-sectional view of a conventional photoelectric composite module, and FIG. 7B is a schematic plan view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Optical monitor element 3 Drive LSI
4 Photoelectric Composite Module 41 Heat Dissipation Board 42 Insulating Layer 43 Wiring Board 51 Optical Fiber 60, 61 DC Line 62, 63, 64 High Speed Signal Line 65 Lower Ground Line 68 Upper Ground Line 66 Bump 67, 69, 75 Via 7 Insulating Layer 71 72 Optical waveguide

Claims (6)

A light emitting element installed on a heat dissipation substrate and generating an optical signal;
An optical waveguide that transmits at least one of the optical signal output surface of the light emitting element and the surface opposite to the output surface, and transmits the optical signal generated by the light emitting element;
An insulating layer provided on the heat dissipation substrate and containing the optical waveguide;
A driving LSI which is flip-chip mounted on the upper surface of the insulating layer and supplies a current amplification signal to the light emitting element;
An optical monitoring element installed on the heat dissipation substrate and monitoring light emission of the light emitting element;
A DC line for supplying a monitor signal of the optical monitor element to the drive LSI ;
A driving signal line connecting the driving LSI and the light emitting element in the thickness direction of the insulating layer;
An electrical input transmission line that contacts the drive LSI and extends the upper surface of the insulating layer and supplies an electrical input signal to the drive LSI;
The transmission line for electrical input is
An upper ground line extending in contact with the drive LSI and extending the upper surface of the insulating layer;
A lower ground line extending from the upper surface of the heat dissipation substrate;
A ground electrode connecting portion for connecting the upper ground line and the lower ground line;
A photoelectric composite module comprising: The ground electrode connecting portion, the a via extending vertically insulating layer in a position not interfering with the optical waveguide, an optical-electrical composite module according to claim 1. The optoelectric composite module according to claim 1 , wherein the insulating layer has a coplanar line including the upper ground electrode on an upper surface.   The photoelectric composite module according to claim 1, wherein the insulating layer is made of a polymer resin material.   2. The photoelectric composite module according to claim 1, further comprising: an optical fiber that is installed in a guide mechanism on a heat dissipation substrate on which the waveguide type optical element is installed and is connected to the optical waveguide to input and output light. A plurality of the optical waveguide is formed in an array, the light emitting element to each of the optical waveguides is connected, the optical-electrical composite module according to claim 1.

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