Optical module

Abstract

To provide an optical module that enables easy positioning of components while miniaturizing the device. [Solution] The optical module 10 includes a first cavity 110 having a first side surface S1 and a second side surface S2 that are orthogonal to the first substrate in a plan view. The optical module 10 also includes an optical transmitter 120 having a first edge E1 that is orthogonal to the first side surface S1 in a plan view with respect to the first substrate 100. The optical module 10 also includes a second cavity 210 on the second substrate 200, located below the first cavity 110, and having a third edge E3 that is parallel to the first side surface S1 in a plan view with respect to the second substrate 200. Furthermore, the optical module 10 forms a positioning mechanism for an optical coupling member 20 connected to the optical transmitter 120 and the optical receiver 220 using the first edge E1, the second edge E2 which is the first side surface S1 of the first cavity 110, and the third edge E3.

Description

Technical Field

[0001] The present invention relates to an optical module.

Background Art

[0002] Conventionally, techniques have been proposed for easily implementing the alignment accuracy between an optical semiconductor element used in an optical integration element and other components. Patent Document 1 discloses an optical semiconductor element. The optical semiconductor element disclosed in Patent Document 1 facilitates positioning with different components by providing a protruding portion protruding from a substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The optical semiconductor element disclosed in Patent Document 1 needs to form a protruding portion for positioning, which leads to an increase in the size of the element. Therefore, there is a need for a device that can easily perform member positioning while achieving miniaturization.

[0005] The present invention has been made in view of such problems of the prior art. The object of the present invention is to provide an optical module that can easily perform member positioning while achieving miniaturization of the device.

Means for Solving the Problems

[0006] An optical module according to an aspect of the present invention is mounted on a multilayer substrate comprising a first substrate, a second substrate provided at the bottom of the first substrate in a first direction corresponding to the direction perpendicular to the substrate plane, and a third substrate provided at the bottom of the second substrate in the first direction, and performs optical transmission and reception, and comprises a first cavity provided on the first substrate and having a first side surface and a second side surface that are orthogonal to the first substrate in a plan view, and inside the first cavity, in contact with the first side surface of the first cavity and provided on the upper surface of the second substrate in the first direction, The optical device comprises: an optical transmitter having a first edge perpendicular to the first side surface in a plan view of one substrate; a second cavity provided on the second substrate at the lower part of the first cavity in a first direction and having a third edge parallel to the first side surface in a plan view of the second substrate; and an optical receiver provided on the upper surface in a first direction of the third substrate inside the second cavity. The first edge, the second edge which is the first side surface of the first cavity, and the third edge form a positioning mechanism for an optical coupling member connected to the optical transmitter and optical receiver. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an optical module that enables easy positioning of components while miniaturizing the device. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view illustrating the substrate on which the optical module according to this embodiment is provided. [Figure 2] This is a plan view illustrating a substrate on which the optical module according to this embodiment is provided. [Figure 3A] This is a plan view showing the configuration of the optical module according to this embodiment. [Figure 3B] This is a plan view showing the configuration of the optical module according to this embodiment. [Figure 4] This is a plan view showing the configuration of the optical module according to this embodiment. [Figure 5A] This is a perspective view showing the configuration of the optical module according to this embodiment. [Figure 5B] This is a perspective view showing the configuration of the optical module according to this embodiment. [Figure 6] This is a cross-sectional view showing the configuration of the optical module according to this embodiment. [Figure 7] This is a cross-sectional view showing the configuration of the optical module according to this embodiment. [Figure 8] This figure illustrates the optical coupling image provided by the optical module according to this embodiment. [Figure 9A] This figure illustrates the optical coupling image provided by the optical module according to this embodiment. [Figure 9B] This figure illustrates the optical coupling image provided by the optical module according to this embodiment. [Modes for carrying out the invention]

[0009] The optical module 10 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios. In addition, in the following drawings, identical or similar parts are denoted by the same or similar reference numerals.

[0010] The optical module 10 according to this embodiment is a device that is mounted on a high-frequency multilayer substrate and performs optical transmission and reception.

[0011] Figure 1 is a perspective view illustrating a substrate on which the optical module 10 according to this embodiment is provided. As shown in Figure 1, the multilayer substrate on which the optical module 10 is provided comprises a first substrate 100, a second substrate 200 provided at the bottom of the first substrate 100 in a first direction corresponding to the direction perpendicular to the substrate plane, and a third substrate 300 provided at the bottom of the second substrate 200 in the first direction.

[0012] In the following explanation, the plane formed by the X-axis and Y-axis directions shown in Figure 1 is referred to as the substrate plane. The Z-axis direction corresponds to the direction perpendicular to the substrate plane.

[0013] FIG. 2 is a plan view for explaining a substrate on which the optical module 10 according to the present embodiment is provided. As shown in FIGS. 1 and 2, a first cavity 110, which is a rectangular hole, is formed in the first substrate 100. That is, the first cavity 110 is provided in the first substrate 100 and is formed in a rectangular shape in a plan view with respect to the first substrate 100. Further, in the present embodiment, four side surfaces of the first cavity 110 are defined as a first side surface S1, a second side surface S2, a third side surface S3, and a fourth side surface S4 as shown in FIG. 2. That is, the first cavity 110 is provided in the first substrate 100 and has the first side surface S1 and the second side surface S2 that are orthogonal to each other in a plan view with respect to the first substrate 100.

[0014] Also, as shown in FIGS. 1 and 2, a second cavity 210, which is a rectangular hole, is formed in the second substrate 200. That is, the second cavity 210 is provided in the second substrate 200 below the first cavity 110 in the first direction and is formed in a rectangular shape in a plan view with respect to the second substrate 200. Further, in the present embodiment, the second cavity 210 has four sides that are parallel to the four sides of the first cavity 110 in a plan view. Note that the four sides of the first cavity 110 correspond to the four sides when the first side surface S1, the second side surface S2, the third side surface S3, and the fourth side surface S4 in FIG. 2 are viewed in a plan view. That is, the second cavity 210 is provided in the second substrate 200 below the first cavity 110 in the first direction and has a third edge E3 that is parallel to the first side surface S1 in a plan view with respect to the second substrate 200.

[0015] (Configuration of Optical Module 10) FIG. 3A and FIG. 3B are plan views showing the configuration of the optical module 10 according to the present embodiment. The optical module 10 includes an optical transmitter 120 and an optical receiver 220. The first substrate 100, which is the first layer of the multilayer substrate, forms transmission path patterns 101 and 102 on the surface layer, and has the transmission path patterns 101 and 102 and an insulating layer. The transmission path patterns 101 and 102 shown in FIG. 3A may be provided on the second substrate 200 as shown in FIG. 3B. That is, the second substrate 200, which is the second layer of the multilayer substrate, may also form transmission path patterns 201 and 202 on the surface layer, and have the transmission path patterns 201 and 202 and an insulating layer as shown in FIG. 3B.

[0016] The optical transmitter 120 is provided inside the first cavity 110 and in contact with the first side surface S1 of the first cavity 110. Further, the optical transmitter 120 is provided on the upper surface in the first direction of the second substrate 200. Further, the optical transmitter 120 is formed in a rectangular shape in a plan view with respect to the first substrate 100. Further, in a plan view, the four sides of the optical transmitter 120 are parallel to the four sides of the first cavity 110. That is, the optical transmitter 120 is provided inside the first cavity 110, in contact with the first side surface S1 of the first cavity 110, on the upper surface in the first direction of the second substrate 200, and has a first edge E1 orthogonal to the first side surface S1 in a plan view with respect to the first substrate 100.

[0017] The optical receiver 220 is provided inside the second cavity 210 and on the upper surface in the first direction of the third substrate 300. Further, the optical receiver 220 includes a photodiode 221, a transimpedance amplifier 222 (TIA), and a bonding wire 223 that connects the photodiode 221 and the transimpedance amplifier 222. The transimpedance amplifier 222 mounted in the second cavity 210 may be configured to be formed on the surface layer of the first substrate 100 or the surface layer of the second substrate 200.

[0018] Figure 4 is a plan view showing the configuration of the optical module 10 according to this embodiment, and shows the configuration when the optical coupling member 20 is mounted. In the optical module 10 according to this embodiment, a positioning mechanism for the optical coupling member 20 is formed based on the optical transmitter 120, the first cavity 110, and the second cavity 210, and the first edge E1, second edge E2, and third edge E3 formed on the second cavity 210.

[0019] Specifically, the edge on the side of the optical transmitter 120 that is perpendicular (orthogonal) to the first side surface S1 is configured as the first edge E1. The edge of the first cavity 110 corresponding to the first side surface S1 is configured as the second edge E2. Furthermore, the edge formed on the side of the second cavity 210 that is parallel to the second edge E2 and closer to the optical transmitter 120 is configured as the third edge E3.

[0020] For example, in the example shown in Figure 4, the first edge E1 determines the position of the optical coupling member 20 in the X-axis direction. The second edge E2 determines the position of the optical coupling member 20 in the Y-axis direction. Furthermore, the third edge E3 makes it possible to define the boundary between the optical transmitting side and the optical receiving side of the optical coupling member 20.

[0021] Furthermore, as shown in Figure 4, by using the second edge E2, the first edge E1 and the second edge E2 of the optical transmitter 120 (optical transmission module) become orthogonal. In other words, in this embodiment, the optical module 10 has a positioning configuration formed using the first edge E1 and the second edge E2, or the first edge E1 and the third edge E3, or the first edge E1, the second edge E2, and the third edge E3.

[0022] As a result, the optical module 10 according to this embodiment does not require a separate mechanism for positioning the optical coupling member 20 to be provided on the substrate, making it possible to easily position the member while miniaturizing the device.

[0023] Furthermore, in addition to the first cavity 110 containing the optical transmitter 120, the optical module 10 also has a second cavity 210 containing the optical receiver 220, which is provided on a separate substrate. This makes it possible for the optical module 10 to improve optical isolation at the optical coupling portion of the optical transmitter 120 and the optical receiver 220, as well as the isolation of the high-frequency electrical circuit.

[0024] Furthermore, if the substrate pressure interferes with the lens of the optical coupling member 20, the first cavity 110 and the second cavity 210 of the optical module 10 may be extended to the edge of the substrate. Figure 5A is a diagram showing the configuration of the optical module 10 according to this embodiment, and is a perspective view corresponding to the configuration of Figure 4. Figure 5B is a perspective view showing the configuration of the optical module 10 according to this embodiment, and shows the case where the first cavity 110 and the second cavity 210 are extended to the edge of the substrate. The configuration shown in Figure 5B makes it possible to prevent the substrate pressure from interfering with the lens of the optical coupling member 20.

[0025] Furthermore, as shown in Figures 5A and 5B, the bonding wires 223 of the optical receiver 220 are housed inside the second cavity 210 in the Z-axis direction. That is, the length of the second cavity 210 in the first direction (Z-axis direction) is longer than the length of the optical receiver 220 in the first direction. As a result, the optical module 10 can be miniaturized by housing the optical receiver 220 in the second cavity 210.

[0026] Furthermore, as shown in the cross-sectional view of Figure 6, an example is shown in which the photodiode 221 of the optical receiver 220 is formed inside the second cavity 210. However, for example, the photodiode 221 may be formed on the back surface (lower vertical side) of the multilayer substrate, as shown in Figure 7. In the example shown in Figure 7, the photodiode 221a is connected to the optical coupling member 20 via a through-hole 30. This makes it possible for the optical module 10 to improve its coupling characteristics (optical coupling efficiency) without forming a waveguide. Note that the configuration in which the photodiode 221a is connected to the optical coupling member 20 is not limited to a through-hole 30, but may also be via. In addition, the photodiode 221 may be mounted in a cavity formed in the fourth substrate 400 or the fifth substrate 500.

[0027] Figure 8 is a diagram illustrating an optical coupling image using the optical module 10 according to another embodiment. By cutting the output end face of the optical transmitter 120 diagonally as shown in Figure 8, and by using a multimode fiber with a core diameter of 50 μm or more as the optical coupling optical fiber 40, it becomes possible to couple the light emitted from the optical transmitter 120 to the optical fiber 40 by spatial coupling using the optical coupling member 20.

[0028] In the example shown in Figure 8, the light emitted from the optical transmitter 120 is shown to be emitted from the edge (end face), but the configuration of the embodiment is not limited to this. For example, as shown in Figures 9A and 9B, the light may be emitted vertically. For example, as shown in Figure 9B, by forming a cavity and mounting a device such as the optical transmitter 120, it is possible to suppress the height of the device and shorten the length of the wire bonding connected to the transmission line. As a result, the optical module 10 can more easily maintain higher frequency characteristics.

[0029] As described above, the optical module 10 according to this embodiment comprises a first substrate 100, a second substrate 200 provided at the lower part of the first substrate 100 in a first direction corresponding to the direction perpendicular to the substrate plane, and a third substrate 300 provided at the lower part of the second substrate 200 in the first direction. The optical module 10 also includes a first cavity 110 provided on the first substrate 100, having a first side surface S1 and a second side surface S2 that are orthogonal to the first substrate 100 in a plan view. Inside the first cavity 110, the optical module includes an optical transmitter 120 that is in contact with the first side surface S1 of the first cavity 110, provided on the upper surface of the second substrate 200 in a first direction, and having a first edge E1 that is orthogonal to the first side surface S1 in a plan view of the first substrate 100. Furthermore, the optical module 10 includes a second cavity 210 on the second substrate 200, located at the lower part of the first cavity 110 in the first direction, and having a third edge E3 parallel to the first side surface S1 in a plan view of the second substrate 200. The optical module 10 also includes an optical receiver 220 located inside the second cavity 210, on the upper surface of the third substrate 300 in the first direction. Moreover, the optical module 10 forms a positioning mechanism for the optical coupling member 20 connected to the optical transmitter 120 and the optical receiver 220 using the first edge E1, the second edge E2 which is the first side surface S1 of the first cavity 110, and the third edge E3.

[0030] As a result, the optical module 10 does not need to have a separate mechanism on the substrate for positioning the optical coupling member 20, making it possible to easily position the member while miniaturizing the device.

[0031] Furthermore, in addition to the first cavity 110 containing the optical transmitter 120, the optical module 10 also has a second cavity 210 containing the optical receiver 220, which is provided on a separate substrate. This makes it possible for the optical module 10 to improve optical isolation at the optical coupling portion of the optical transmitter 120 and the optical receiver 220, as well as the isolation of the high-frequency electrical circuit.

[0032] Furthermore, the optical receiver 220 may include a photodiode 221, a transimpedance amplifier 222, and bonding wires 223 connecting the photodiode 221 and the transimpedance amplifier 222. Also, the length of the second cavity 210 in the first direction may be longer than the length of the optical receiver 220 in the first direction. This makes it possible to miniaturize the optical module 10 by housing the optical receiver 220 in the second cavity 210.

[0033] Furthermore, the optical receiver 220 may also include a photodiode 221a. The photodiode 221a may be located below another substrate provided at the lower part of the third substrate 300 in the first direction, and connected to the optical coupling member 20 via through-holes 30 provided in the third substrate 300 and the other substrate. As a result, the photodiode 221a of the optical module 10 is connected to the optical coupling member 20 via the through-holes 30. This makes it possible for the optical module 10 to improve its coupling characteristics (optical coupling efficiency) without forming a waveguide.

[0034] (Other embodiments) While embodiments have been described in detail with reference to the drawings, these embodiments are not limited to those described above. Furthermore, the components described above include those easily conceivable by those skilled in the art, and those that are substantially the same. Moreover, the configurations described above can be combined as appropriate. In addition, various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

[0035] The features of the optical module 10 are described below.

[0036] The optical module 10 according to the first embodiment comprises a first substrate 100, a second substrate 200 provided at the lower part of the first substrate 100 in a first direction corresponding to the direction perpendicular to the substrate plane, and a third substrate 300 provided at the lower part of the second substrate 200 in the first direction. The optical module 10 is mounted on a multilayer substrate comprising the first substrate 100, the second substrate 200, and the third substrate 300, and is an optical module 10 that performs optical transmission and reception. The optical module 10 also comprises a first cavity 110 provided on the first substrate 100, having a first side surface S1 and a second side surface S2 that are orthogonal to the first substrate 100 in a plan view. Inside the first cavity 110, the optical module comprises an optical transmitter 120 that is in contact with the first side surface S1 of the first cavity 110, provided on the upper surface of the second substrate 200 in a first direction, and having a first edge E1 that is orthogonal to the first side surface S1 in a plan view of the first substrate 100. Furthermore, the optical module 10 includes a second cavity 210 on the second substrate 200, located at the lower part of the first cavity 110 in the first direction, and having a third edge E3 parallel to the first side surface S1 in a plan view of the second substrate 200. The optical module 10 also includes an optical receiver 220 located inside the second cavity 210, on the upper surface of the third substrate 300 in the first direction. Moreover, the optical module 10 forms a positioning mechanism for the optical coupling member 20 connected to the optical transmitter 120 and the optical receiver 220 using the first edge E1, the second edge E2 which is the first side surface S1 of the first cavity 110, and the third edge E3.

[0037] According to the above configuration, the optical module 10 does not require a separate substrate for positioning the optical coupling member 20, making it possible to easily position the member while miniaturizing the device. Furthermore, in this embodiment, the optical module 10 has a second cavity 210 equipped with an optical receiver 220, in addition to the first cavity 110 equipped with an optical transmitter 120, provided on a separate substrate. As a result, the optical module 10 can improve optical isolation at the optical coupling portion of the optical transmitter 120 and the optical receiver 220, as well as the isolation of the high-frequency electrical circuit.

[0038] The optical receiver 220 of the optical module 10 according to the second embodiment may include a photodiode 221, a transimpedance amplifier 222, and bonding wires 223 connecting the photodiode 221 and the transimpedance amplifier 222. Also, the length of the second cavity 210 in the first direction may be longer than the length of the optical receiver 220 in the first direction.

[0039] With the above configuration, the optical module 10 can be miniaturized by housing the optical receiver 220 in the second cavity 210.

[0040] The optical receiver 220 of the optical module 10 according to the third embodiment may include a photodiode 221a. The photodiode 221a may be provided below another substrate provided below the third substrate 300 in the first direction and connected to the optical coupling member 20 via through holes 30 provided in the third substrate 300 and the other substrate.

[0041] According to the above configuration, the photodiode 221a of the optical module 10 is connected to the optical coupling member 20 via the through-hole 30. This makes it possible for the optical module 10 to improve its coupling characteristics (optical coupling efficiency) without forming a waveguide. [Explanation of Symbols]

[0042] 10 Optical Modules 20 Optical coupling member 30 through-holes 40 Fiber Optics 100 First board Transmission line patterns 101, 102, 201, 202 110 First Cavity 120 Optical Transmitters 200 Second board 210 Second Cavity 220 Optical receiver 221, 221a Photodiode 222 Transimpedance Amplifier 223 Bonding Wire 300 Third board 400 Fourth board 500 Fifth substrate

Claims

1. An optical module for transmitting and receiving light is mounted on a multilayer substrate comprising a first substrate, a second substrate provided at the lower part of the first substrate in a first direction perpendicular to the substrate plane, and a third substrate provided at the lower part of the second substrate in the first direction, A first cavity provided on the first substrate, having a first side surface and a second side surface that are orthogonal to the first substrate in a plan view, Inside the first cavity, there is an optical transmitter that is in contact with the first side surface of the first cavity, is provided on the upper surface of the second substrate in the first direction, and has a first edge perpendicular to the first side surface when viewed in plan with respect to the first substrate, In the second substrate, a second cavity is provided at the lower part of the first cavity in the first direction, and in a plan view with respect to the second substrate, has a third edge parallel to the first side surface, The second cavity contains an optical receiver provided on the upper surface of the third substrate in the first direction, An optical module in which the first edge, the second edge which is the first side surface of the first cavity, and the third edge form a positioning mechanism for an optical coupling member connected to the optical transmitter and the optical receiver.

2. The optical receiver comprises a photodiode, a transimpedance amplifier, and bonding wires connecting the photodiode and the transimpedance amplifier. The optical module according to claim 1, wherein the length of the second cavity in the first direction is longer than the length of the optical receiver in the first direction.

3. The aforementioned optical receiver is equipped with a photodiode, The optical module according to claim 1, wherein the photodiode is provided below another substrate provided below the third substrate in the first direction, and is connected to the optical coupling member via through holes or vias provided in the third substrate and the other substrate.

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