Optical transceiver and optical communication device

Abstract

Provided is an optical transceiver, said optical transceiver comprising: a light-emitting element which outputs light; a light-receiving element which receives light and which outputs an electric signal corresponding to the light; a drive circuit which drives the light-emitting element; a processing circuit which processes the electric signal from the light-receiving element; a first substrate on which the light-emitting element, the light-receiving element, the drive circuit, and the processing circuit are mounted; a housing which houses the light-emitting element, the light-receiving element, the drive circuit, and the processing circuit; a control circuit which controls the drive circuit and the processing circuit; a second substrate which has a mounting part that the control circuit is mounted to and a connection part that is flexible; and an electric interface which is provided to the first substrate and which electrically connects the optical transceiver and an external device, wherein the second substrate is attached to a wall surface of the housing via the mounting part.

Description

Optical transceiver and optical communication device

[0001] The present invention relates to an optical transceiver and an optical communication device.

[0002] Patent Documents 1 to 3 disclose known optical transceivers. Meanwhile, in a network switch device that realizes co-packaged optics (CPO), a switch ASIC (application specific integrated circuit) and multiple optical transceivers are mounted on a board. Patent Document 4, for example, discloses a board assembly invention on which multiple optical transceivers are mounted, in which multiple optical transceivers are fixed to the board by a fixing mechanism.

[0003] JP 2017-228965 A JP 2021-173875 A JP 2022-114606 A JP 2023-150085 A

[0004] There is a demand for smaller optical transceivers of this type.

[0005] The present invention has been made in view of the above, and an object of the present invention is to provide a smaller optical transceiver and an optical communication device including the same.

[0006] In order to solve the above-mentioned problems and achieve the object, one aspect of the present invention is an optical transceiver comprising: a light-emitting element that outputs light; a light-receiving element that receives light and outputs an electrical signal corresponding to the light; a drive circuit that drives the light-emitting element; a processing circuit that processes the electrical signal from the light-receiving element; a first board on which the light-emitting element, the light-receiving element, the drive circuit, and the processing circuit are mounted; a housing that accommodates the light-emitting element, the light-receiving element, the drive circuit, and the processing circuit; a control circuit that controls the drive circuit and the processing circuit; a second board having a mounting portion on which the control circuit is mounted and a flexible connection portion; and an electrical interface provided on the first board that electrically connects the optical transceiver to an external device, wherein the second board is an optical transceiver that is attached to the wall surface of the housing at the mounting portion.

[0007] The second substrate may be electrically connected to the first substrate at the connection portion.

[0008] The drive circuit, the processing circuit, and the control circuit may be in thermal contact with the housing via a thermally conductive material, and heat generated by the drive circuit, the processing circuit, and the control circuit may be dissipated in the same direction through the housing.

[0009] The wall surface may be parallel to or intersect with a first surface of the first substrate on which the drive circuit and the processing circuit are mounted.

[0010] The housing may include a mounting structure having the wall surface.

[0011] The mounting structure may be a groove, a recess, a hole, or a countersink provided in the housing.

[0012] The optical transceiver may include electronic components mounted on a second surface of the first substrate opposite to a first surface on which the drive circuit and the processing circuit are mounted, and a housing member attached to the second surface for housing the electronic components.

[0013] The housing may be made of a material with good thermal conductivity.

[0014] The second substrate may be electrically connected to the first substrate by solder, conductive adhesive, anisotropic conductive adhesive, or an electrical connector.

[0015] The electrical interface may include a land grid array.

[0016] The optical transceiver may include a positioning pin that penetrates at least the first substrate and fits into a positioning hole provided in the housing.

[0017] The housing may have a positioning hole, and a positioning pin provided in a fixing mechanism that fixes the optical transceiver to a board may penetrate at least the first board and fit into the positioning hole.

[0018] The optical transceiver may include an optical fiber extending in a direction intersecting the first substrate.

[0019] One aspect of the present invention is an optical communication apparatus including a plurality of the optical transceivers and an electrical device electrically connected to the plurality of optical transceivers.

[0020] According to the present invention, it is possible to realize a smaller optical transceiver and an optical communication device equipped with the same.

[0021] FIG. 1 is a schematic configuration diagram of an optical communication device including an optical transceiver according to a first embodiment. FIG. 2 is a schematic exploded perspective view of the optical transceiver according to the first embodiment. FIG. 3 is a side view of the optical transceiver shown in FIG. 1. FIG. 4 is a partially exploded perspective view of the optical transceiver shown in FIG. 1. FIG. 5 is a perspective view of a second board and a control circuit shown in FIG. 1. FIG. 6 is a schematic perspective view of an optical transceiver according to a second embodiment. FIG. 7 is a side view of the optical transceiver shown in FIG. 6. FIG. 8 is a perspective view of the second board and the control circuit shown in FIG. 6. FIG. 9 is a schematic perspective view of an optical transceiver according to a third embodiment. FIG. 10 is a top view of the optical transceiver shown in FIG. 9. FIG. 11 is a perspective view of the second board and the control circuit shown in FIG. 9. FIG. 12 is an explanatory diagram of a modified example of the optical transceiver according to the second embodiment. FIG. 13 is an explanatory diagram of a modified example of the optical transceiver according to the first embodiment. FIG. 14 is a top view of the optical transceiver shown in FIG. 13. FIG. 15 is a perspective view of a modified example of the second board.

[0022] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to this embodiment. Furthermore, in each drawing, the same or corresponding elements are appropriately designated by the same reference numerals, and duplicated explanations will be omitted. Furthermore, x, y, and z orthogonal coordinate axes are appropriately shown in the drawings, and directions will be explained using these axes.

[0023] First Embodiment In the following, a switch device, which is an optical communication device including an optical transceiver according to a first embodiment, will be described first, and then the optical transceiver according to the first embodiment will be described.

[0024] [Optical Communication Device] FIG. 1 is a schematic configuration diagram of a switch device, which is an optical communication device including an optical transceiver according to a first embodiment.

[0025] 1 , the switch device 100 is mounted on a motherboard 200, similar to the switch device disclosed in Patent Document 4. In this embodiment, only one switch device 100 is mounted on the motherboard 200, but multiple switch devices 100 may be mounted on the motherboard 200. The motherboard 200 constitutes an optical communication device that is higher in level than the switch device 100. The higher-level optical communication device is also an optical communication device that includes the optical transceiver according to the first embodiment.

[0026] The switch device 100 includes a substrate 10 having an electrical wiring pattern formed inside and on its surface, a switch ASIC 20, a plurality of optical transceivers 30, a heat sink 21 for the switch ASIC 20, and a fixing mechanism 40 that fixes the optical transceivers 30 to the substrate 10. Of the components of the switch device 100, the substrate 10 and the fixing mechanism 40 are referred to as a substrate assembly. The substrate assembly can be mounted on a motherboard 200.

[0027] The substrate 10 has a square (quadrilateral) shape. The substrate 10 extends perpendicular to the z-axis and has a plate-like shape.

[0028] Each optical transceiver 30 receives an optical signal transmitted through an optical fiber cord (described later) and outputs an electrical signal corresponding to the optical signal. The electrical signal output from the optical transceiver 30 is input to the switch ASIC 20 via an electrical interface provided in the optical transceiver 30 and a conductor provided on the substrate 10. The optical transceiver 30 has a photodiode array as a plurality of light-receiving units for receiving the optical signal. Each optical transceiver 30 also receives an electrical signal from the switch ASIC 20 via the substrate 10 and the electrical interface and outputs an optical signal corresponding to the electrical signal. The optical signal output from the optical transceiver 30 is coupled to the optical fiber cord and transmitted through the optical fiber cord. The optical transceiver 30 has, for example, a VCSEL (vertical cavity surface emitting laser) array as a plurality of light-emitting units for outputting the optical signal.

[0029] The optical transceivers 30 are arranged along each side 10c of the substrate 10. In this embodiment, each optical transceiver 30 is mounted so as to cover the corresponding side 10c. In other words, when viewed in the negative direction of the z-axis, each optical transceiver 30 is arranged so as to straddle the side 10c, and has a portion located inside the side 10c and a portion located outside the side 10c. This arrangement has the advantages of making it easier to avoid interference between the optical fiber cords extending from the optical transceivers 30 and other components mounted on the substrate 10, such as the switch ASIC 20 and heat sink 21, and allowing the substrate 10 to be made smaller.

[0030] The optical transceivers 30 are fixed to the substrate 10 by fixing mechanisms 40 provided on each side 10 c of the substrate 10. A total of four fixing mechanisms 40 are provided, one on each of the four sides 10 c, and are shared by the multiple (eight in this embodiment, for example) optical transceivers 30 arranged along each side 10 c. By sharing the fixing mechanism 40 among the multiple optical transceivers 30 in this manner, it is possible to simplify the attachment structure of the fixing mechanism 40 to the substrate 10 and reduce the number of parts compared to when each optical transceiver 30 is fixed to the substrate 10 by its own fixing mechanism, thereby achieving the advantages of reducing the effort and cost required to manufacture the switch device 100.

[0031] The switch ASIC 20 is mounted on the substrate 10 at a position away from each of the sides 10c of the substrate 10 (approximately the center of the substrate 10 in this embodiment, as an example). The switch ASIC 20 is mounted, for example, by flip-chip mounting on the surface of the substrate 10 facing the positive direction of the z-axis. The switch ASIC 20 controls the operation of each optical transceiver 30. The switch ASIC 20 is an example of an electrical device electrically connected to multiple optical transceivers 30.

[0032] The heat sink 21 is provided in contact with the switch ASIC 20 on the side opposite the substrate 10. The heat sink 21 is in contact with the top surface of the switch ASIC 20 and has an array of pin-shaped fins 21a protruding from the base in the positive direction of the z-axis. The heat sink 21 is made of a thermally conductive material with relatively high thermal conductivity, such as an aluminum-based metal material. With this configuration, heat generated by the switch ASIC 20 is transferred in the positive direction of the z-axis through the heat sink 21 and transferred to the surrounding gas, i.e., released, through heat exchange between the fins 21a and the gas surrounding the fins 21a. The heat sink 21 and the switch ASIC 20 may be in contact with each other via thermally conductive grease or the like, or may be in direct contact with each other.

[0033] [Optical Transceiver] Fig. 2 is a schematic exploded perspective view of the optical transceiver according to the first embodiment. Fig. 3 is a side view of the optical transceiver shown in Fig. 1. Fig. 4 is a partially exploded perspective view of the optical transceiver shown in Fig. 1. The optical transceiver 30 includes a first substrate 31 having an electrical wiring pattern formed inside and on its surface, a housing 32, a connectorized optical fiber cord 33, a lens assembly 35, lower frames 36a and 36b, two screw members 37, two positioning pins 38, and two heat-conducting materials 39. Note that the connectorized optical fiber cord 33 is not shown in Figs. 3 and 4.

[0034] The first substrate 31 extends perpendicular to the z-axis and has a plate-like shape. The first substrate 31 has a first surface 31a facing in the positive direction of the z-axis and a second surface 31b on the opposite side of the first surface 31a facing in the negative direction of the z-axis. Furthermore, the first substrate 31 is provided with two screw holes 31c that penetrate in the z-axis direction and two positioning holes 31d. Screw members 37 are inserted into the screw holes 31c, and positioning pins 38 are inserted and fixed into the positioning holes 31d.

[0035] As shown in Fig. 3, a light-emitting element 34a that outputs an optical signal and a light-receiving element 34b that receives the optical signal and outputs an electrical signal corresponding to the optical signal are mounted on the first surface 31a of the first substrate 31. Here, in Fig. 3, the light-emitting element 34a is located at the rear of the drawing (negative side of the y-axis), and the light-receiving element 34b is located at the front of the drawing (positive side of the y-axis) relative to the light-emitting element 34a. In this embodiment, the light-emitting element 34a is a 4-channel x 2-column VCSEL array element, and the light-receiving element 34b is a 4-channel x 2-column photodiode array element.

[0036] 2 and 3, two drive circuits 34c that drive the light-emitting elements 34a and two processing circuits 34d that process electrical signals from the light-receiving elements 34b are mounted on the first surface 31a. The drive circuits 34c are electrically connected to the light-emitting elements 34a via the first substrate 31, and the processing circuits 34d are electrically connected to the light-receiving elements 34b via the first substrate 31. The drive circuits 34c are configured to include, for example, a drive IC, and the processing circuits 34d are configured to include, for example, a transimpedance amplifier.

[0037] 3 and 4, a plurality of electronic components 34e are mounted on the second surface 31b of the first substrate 31. The electronic components 34e are resistors and capacitors. The electronic components 34e are electrically connected to the drive circuit 34c, the processing circuit 34d, and a control circuit (described later) via the first substrate 31.

[0038] 4, an electrical interface 34f is provided on the second surface 31b of the first substrate 31. The electrical interface 34f electrically connects the optical transceiver 30 to an external device and includes, for example, a land grid array. In this embodiment, the electrical interface 34f electrically connects the optical transceiver 30 to the switch ASIC 20 via the fixing mechanism 40 and the substrate 10.

[0039] 2 and 3, a second substrate 34g is mounted on the first surface 31a of the first substrate 31. A control circuit 34h is mounted on the second substrate 34g.

[0040] 5 is a perspective view of the second substrate 34g and the control circuit 34h. In this embodiment, the second substrate 34g is a flexible substrate with electrical wiring patterns formed inside and on its surface, and is therefore flexible. The second substrate 34g has a mounting portion 34g1 and a connecting portion 34g2. The mounting portion 34g1 is where the control circuit 34h is mounted, and the connecting portion 34g2 is where the first substrate 31 is electrically and mechanically connected. In this embodiment, when the optical transceiver 30 is assembled, the connecting portion 34g2 is bent in an L-shape. The first substrate 31 and the connecting portion 34g2 of the second substrate 34g are electrically and mechanically connected by, for example, solder, a conductive adhesive, or an anisotropic conductive adhesive.

[0041] The control circuit 34h controls the drive circuit 34c and the processing circuit 34d. The control circuit 34h is electrically connected to the drive circuit 34c and the processing circuit 34d via the second board 34g and the first board 31. The control circuit 34h includes, for example, a microcontroller.

[0042] Next, the housing 32 will be described. The housing 32 has a rectangular parallelepiped shape and is made of a material with good thermal conductivity, such as aluminum, a copper-tungsten alloy, or copper. The housing 32 has a through-hole 32a, two first housing portions 32b, two second housing portions 32c, two positioning holes 32d, and two screw fastening portions 32e.

[0043] The through-hole 32a penetrates the housing 32 in the z-axis direction. The two first housing sections 32b are recessed in the positive z-axis direction from the surface (the surface facing the negative z-axis direction) that abuts the first board 31 when the optical transceiver 30 is assembled. The two first housing sections 32b are positioned on either side of the through-hole 32a in the y-axis direction and communicate with the through-hole 32a. The two first housing sections 32b also have top walls 32ba that extend in the x and y directions. As shown in FIGS. 2 and 3 , the housing 32 accommodates the light-emitting element 34a, the light-receiving element 34b, the drive circuit 34c, and the processing circuit 34d through the through-hole 32a and the two first housing sections 32b.

[0044] The second housing portion 32c is a bottomed groove extending from the top wall 32ba of the first housing portion 32b in the positive direction of the z-axis. The second housing portion 32c has an inner wall surface 32ca on the positive or negative side of the y-axis. The inner wall surface 32ca intersects with the first surface 31a, and in this embodiment, is perpendicular to it. The second housing portion 32c accommodates a second substrate 34g and a control circuit 34h. The second substrate 34g is attached to the inner wall surface 32ca, which is a wall surface of the housing 32, at a mounting portion 34g1 (see FIG. 5) on which the control circuit 34h is mounted. This attachment is achieved, for example, using a thermally conductive adhesive. Here, the second housing portion 32c is an example of a mounting structure having a wall surface to which the second substrate is attached, and is an example of a mounting structure in the form of a groove.

[0045] The two positioning holes 32d extend in the positive direction of the z-axis from the surface that abuts against the first board 31 when the optical transceiver 30 is assembled. Positioning pins 38 are inserted and fixed into the positioning holes 32d. The two screw fastening portions 32e consist of a recess that recesses in the negative direction from the surface on the positive z-axis side of the housing 32, and a screw hole that extends further from the recess in the negative z-axis direction and penetrates the housing 32. Screw members 37 are positioned in the screw fastening portions 32e so that the heads of the screw members 37 abut against the recesses and the threaded portions of the screw members 37 are inserted into the screw holes.

[0046] Next, the lens assembly 35 will be described. The lens assembly 35 has a lens array 35a and two positioning pins 35b mounted on a rectangular parallelepiped main body. The lens assembly 35 is mounted on the first surface 31a of the first substrate 31. The lens array 35a includes a condenser lens array in which unit lenses are arranged two-dimensionally in 12 rows and 2 columns, and a collimator lens array in which unit lenses are arranged two-dimensionally in 12 rows and 2 columns. When the optical transceiver 30 is assembled, each unit lens of the condenser lens array is optically connected to each VCSEL of the light-emitting element 34a. Similarly, when the optical transceiver 30 is assembled, each unit lens of the collimator lens array is optically connected to each photodiode of the light-receiving element 34b. The positioning pins 35b extend from the main body in the positive direction of the z-axis and are inserted into positioning holes of the MT connector, which will be described later.

[0047] Next, the connectorized optical fiber cord 33 will be described. The connectorized optical fiber cord 33 includes an optical fiber cord 33a and an MT connector 33b. The optical fiber cord 33a includes two 12-core ribonized fibers. The MT connector 33b is attached to the end of the optical fiber cord 33a. The MT connector 33b has two positioning holes that fit with two positioning pins 35b of the lens assembly 35. The connectorized optical fiber cord 33 is positioned by fitting the two positioning pins 35b into the two positioning holes of the MT connector 33b, and is then attached to the lens assembly 35. When the connectorized optical fiber cord 33 is attached to the lens assembly 35, each of the 24 optical fibers that make up the two ribonized fibers is optically connected to the VCSEL or photodiode described above via the unit lenses that make up the lens array 35a. Furthermore, when the connector-attached optical fiber cord 33 is attached to the lens assembly 35 , the optical fiber cord 33 a extends in a direction intersecting with the first substrate 31 .

[0048] Next, the lower frames 36a and 36b will be described. As shown in FIG. 4 , the lower frames 36a and 36b are attached to the second surface 31b of the first substrate 31 so as to sandwich the electrical interface 34f. The lower frames 36a and 36b are made of, for example, a metal material. The lower frame 36a is a plate-shaped member extending in the x and y directions and includes a screw hole 36aa penetrating in the z-axis direction, a positioning hole 36ab penetrating in the z-axis direction, and an accommodation portion 36ac recessed from the surface facing the positive z-axis toward the negative z-axis direction. When the lower frame 36a is attached to the first substrate 31, a screw member 37 is screwed into the screw hole 36aa, and a positioning pin 38 is inserted and fixed into the positioning hole 36ab. Furthermore, as shown in FIG. 3 , the accommodation portion 36ac accommodates an electronic component 34e. Here, the lower frame 36b is an example of an accommodation member that accommodates an electronic component. The lower frame 36b is a plate-like member extending in the x and y directions, and is provided with a screw hole 36ba that penetrates in the z-axis direction and a positioning hole 36bb that penetrates in the z-axis direction. When the lower frame 36b is attached to the first substrate 31, a screw member 37 is screwed into the screw hole 36ba, and a positioning pin 38 is inserted and fixed into the positioning hole 36bb.

[0049] Next, the screw member 37 and the positioning pin 38 will be described. The screw member 37 is sequentially inserted into the screw hole of the screw fastening portion 32e of the housing 32 and the screw hole 31c of the first substrate 31, and is screwed into the screw hole 36aa of the lower frame 36a or the screw hole 36ba of the lower frame 36b. This fastens the housing 32, the first substrate 31, and the lower frames 36a, 36b together. The positioning pin 38 is a cylindrical member made of, for example, metal. The positioning pin 38 sequentially passes through the positioning hole 36ab of the lower frame 36a or the positioning hole 36bb of the lower frame 36b and the positioning hole 31d of the first substrate 31, and may be fitted into the positioning hole 32d of the housing 32 and fixed thereto with an adhesive or the like. The positioning pin 38 functions to accurately align the relative positions of the lower frames 36a, 36b, the first substrate 31, and the housing 32. The positioning pin 38 is used for positioning when the optical transceiver 30 is mounted on the fixing mechanism 40 shown in Fig. 1. The positioning pin 38 does not necessarily have to be provided on the optical transceiver 30, but may be provided on the fixing mechanism 40.

[0050] 3 thermally connects the drive circuit 34c and the processing circuit 34d to the top wall 32ba of the first housing portion 32b of the housing 32. The heat conductive material 39 includes, for example, a silicone resin or a thermally conductive adhesive, and is filled in the space between the drive circuit 34c and the processing circuit 34d and the top wall 32ba.

[0051] In the optical transceiver 30 according to the first embodiment configured as described above, the control circuit 34h is attached to the inner wall surface 32ca of the housing 32 by the second board 34g, so there is no need to secure space on the first board 31 for mounting the control circuit 34h. As a result, the optical transceiver 30 is compact, and in particular, the area required for mounting is reduced. This also allows the switch device 100 to be compact, or allows more optical transceivers 30 to be mounted relative to its size. Furthermore, because the control circuit 34h is attached to the inner wall surface 32ca of the housing 32, a heat dissipation path for the control circuit 34h is secured within the housing 32.

[0052] As shown in FIG. 3 , in the optical transceiver 30, heat generated by the driver circuit 34c, processing circuit 34d, and control circuit 34h is dissipated in the same direction through the housing 32. Specifically, heat generated by the control circuit 34h is dissipated in the positive direction of the z-axis through the housing 32 as indicated by arrow Ar1. Heat generated by the driver circuit 34c and processing circuit 34d is dissipated in the positive direction of the z-axis through the thermally conductive material 39 and the housing 32 as indicated by arrow Ar2. This facilitates the disposal of heat generated by the driver circuit 34c, processing circuit 34d, and control circuit 34h. For example, by providing a heat dissipation mechanism such as a heat sink on the positive side of the housing 32 facing the z-axis, the heat generated by the driver circuit 34c, processing circuit 34d, and control circuit 34h can be disposed of collectively. Furthermore, in the optical transceiver 30, the housing 32 is made of a highly thermally conductive material, resulting in excellent heat dissipation efficiency.

[0053] Furthermore, in the optical transceiver 30, the lower frame 36a accommodates the electronic components 34e, preventing the electronic components 34e from interfering with the substrate 10 and the like.

[0054] Furthermore, in the optical transceiver 30, at least the connection portion 34g2 of the second substrate 34g is flexible, so even if the inner wall surface 32ca and the first surface 31a are perpendicular to each other and the second substrate 34g is attached to the inner wall surface 32ca, no distortion occurs in the second substrate 34g.

[0055] An example of a method for assembling the optical transceiver 30 will be described. First, the control circuit 34h is mounted on the second substrate 34g. Meanwhile, the light-emitting element 34a, the light-receiving element 34b, the drive circuit 34c, the processing circuit 34d, the electronic components 34e, and the lens assembly 35 are mounted on the first substrate 31. Next, the second substrate 34g is mounted on the first substrate 31. Next, a thermally conductive material 39 is applied. Next, the housing 32 is attached to the first substrate 31. At this time, the lens assembly 35 is accommodated in the through-hole 32a, and the second substrate 34g and the control circuit 34h are accommodated in the second housing portion 32c. Next, the screw member 37 is attached. Next, a thermally conductive adhesive, for example, is applied from the through-hole 32a to the second housing portion 32c, and the second substrate 34g is fixed to the inner wall surface 32ca of the second housing portion 32c.

[0056] Second Embodiment Fig. 6 is a schematic perspective view of an optical transceiver according to a second embodiment. Fig. 7 is a side view of the optical transceiver shown in Fig. 6. The optical transceiver 30A has a configuration in which the housing 32 in the optical transceiver 30 shown in Figs. 2 to 4 is replaced with a housing 32A, and the second board 34g is replaced with a second board 34Ag. Note that Figs. 6 and 7 omit illustration of the connector-attached optical fiber cord 33, the positioning pin 38, and the thermally conductive material 39.

[0057] The housing 32A has a configuration in which the two first housing sections 32b and the two second housing sections 32c of the housing 32 are replaced with two housing sections 32Ag. The two housing sections 32Ag are recessed in the positive direction of the z-axis from the surface (the surface facing the negative direction of the z-axis) that abuts the first substrate 31 when the optical transceiver 30A is assembled. The two housing sections 32Ag are located on either side of the through hole 32a in the y-axis direction and communicate with the through hole 32a. The two housing sections 32Ag also have a top wall 32Aga that extends in the x and y directions. The top wall 32Aga is approximately parallel to the first surface 31a of the first substrate 31.

[0058] FIG. 8 is a perspective view of the second board 34Ag and the control circuit 34h. As shown in FIGS. 6 to 8, the second board 34Ag is a flexible board with electrical wiring patterns formed inside and on its surface. When the optical transceiver 30A is assembled, it is bent into a U-shape and attached to the top wall 32Aga, which is a wall surface of the housing 32A. Here, the housing 32Ag is an example of a mounting structure having a wall surface to which the second board is attached, and is an example of a mounting structure in the form of a recess. Therefore, the housing 32A accommodates the drive circuit 34c, the processing circuit 34d, the second board 34Ag, and the control circuit 34h using the two housings 32Ag.

[0059] The optical transceiver 30A configured as described above is compact, similar to the optical transceiver 30, and a heat dissipation path for the control circuit 34h is secured within the housing 32A. Furthermore, in the optical transceiver 30A, heat generated by the driver circuit 34c, processing circuit 34d, and control circuit 34h is dissipated in the positive direction of the z-axis through the housing 32A. Furthermore, the housing 32A is made of a highly thermally conductive material, resulting in excellent heat dissipation efficiency. Furthermore, no distortion occurs in the second substrate 34Ag.

[0060] (Embodiment 3) Fig. 9 is a schematic perspective view of an optical transceiver according to embodiment 3. Fig. 10 is a top view of the optical transceiver shown in Fig. 9. The optical transceiver 30B has a configuration in which the housing 32 in the optical transceiver 30 shown in Figs. 2 to 4 is replaced with a housing 32B, the second board 34g is replaced with a second board 34Bg, and the thermally conductive material 39 is replaced with a thermally conductive material 39B. Note that the connector-attached optical fiber cord 33 and the positioning pin 38 are not shown in Figs. 9 and 10.

[0061] The housing 32B has a configuration in which the two first housing portions 32b and two second housing portions 32c of the housing 32 are replaced with two first housing portions 32Bb and two counterbore portions 32Bc. The two first housing portions 32Bb are recessed in the positive direction of the z-axis from the surface (the surface facing the negative direction of the z-axis) that abuts the first board 31 when the optical transceiver 30A is assembled, and a protrusion 32Bba that protrudes in the positive direction of the z-axis is formed on the bottom surface of the recess. The two first housing portions 32Bb are located on either side of the through hole 32a in the y-axis direction and are in communication with the through hole 32a. The housing 32B uses the two first housing portions 32Bb to accommodate the drive circuit 34c and the processing circuit 34d. The thermally conductive material 39B thermally connects the drive circuit 34c and the processing circuit 34d to the protrusion 32Bba of the housing 32. The thermally conductive material 39B includes, for example, a silicone resin or a thermally conductive adhesive, and is filled in the space between the drive circuit 34c and the processing circuit 34d and the protrusion 32Bba.

[0062] The two countersunk portions 32Bc are recessed from the side surface of the housing 32B facing the y-axis in either the positive or negative direction of the y-axis, and have wall surfaces 32Bca facing either the positive or negative direction of the y-axis. The wall surfaces 32Bca intersect with the first surface 31a of the first substrate 31, and are perpendicular to each other in this embodiment.

[0063] 11 is a perspective view of the second board 34Bg and the control circuit 34h. As shown in FIGS. 9 to 11, the second board 34Bg is a flexible board with electrical wiring patterns formed inside and on its surface. When the optical transceiver 30B is assembled, it is bent into an L-shape and attached to the wall surface 32bca of the countersunk portion 32Bc, which is a wall surface of the housing 32B. Here, the countersunk portion 32Bc is an example of a mounting structure having a wall surface to which the second board is attached, and is an example of a mounting structure in which the mounting structure is a countersunk portion. The wall surface 32bca of the countersunk portion 32Bc can also be considered the outer wall surface of the housing 32B.

[0064] The optical transceiver 30B configured as described above is compact, similar to the optical transceiver 30, and a heat dissipation path for the control circuit 34h is secured within the housing 32B. Furthermore, in the optical transceiver 30B, heat generated by the driver circuit 34c, processing circuit 34d, and control circuit 34h is dissipated in the positive direction of the z-axis through the housing 32B. Furthermore, the housing 32B is made of a highly thermally conductive material, resulting in excellent heat dissipation efficiency. Furthermore, no distortion occurs in the second substrate 34Bg.

[0065] (Variant) In the above embodiment, the second substrate and the first substrate are electrically and mechanically connected by solder, conductive adhesive, or anisotropic conductive adhesive, but the second substrate and the first substrate may also be electrically and mechanically connected by an electrical connector.

[0066] 12 is an explanatory diagram of a modified example of the optical transceiver according to the second embodiment. In the optical transceiver 30C according to this modification, an electrical connector 34Ci is provided on the second substrate 34Ag, and the second substrate 34Ag and the first substrate 31 are electrically and mechanically connected by the electrical connector.

[0067] Although the second housing 32c is a bottomed groove in the first embodiment, the second housing 32c may be a through-hole. For example, FIG. 13 is an explanatory diagram of a modified example of the optical transceiver according to the first embodiment. FIG. 14 is a top view of the optical transceiver shown in FIG. 13. In the housing 32D of the optical transceiver 30D according to this modified example, the second housing 32Dc corresponding to the second housing 32c of the optical transceiver 30 is a through-hole extending from the top wall of the first housing 32b in the positive direction of the z-axis and has an inner wall surface 32Dca. The second housing 32Dc accommodates a second substrate 34g and a control circuit 34h. The second substrate 34g is attached to the inner wall surface 32Dca, which is the wall surface of the housing 32D, at a mounting portion where the control circuit 34h is mounted. Note that this attachment is achieved, for example, using a thermally conductive adhesive. Here, the second housing 32Dc is an example of a mounting structure having a wall surface to which the second substrate is attached, and is an example of a mounting structure in the form of a hole. Note that the through-hole 32Da corresponding to the through-hole 32a of the optical transceiver 30 does not communicate with the second housing 32Dc. In this case, to fix the second substrate 34g to the inner wall surface 32Dca of the second housing 32Dc, for example, a thermally conductive adhesive is supplied through the opening of the second housing 32Dc.

[0068] In the above embodiment, the entire second substrate is made of a flexible substrate. However, as shown in a modified example of the second substrate in FIG. 15, the mounting portion 34Eg1 of the second substrate 34Eg on which the control circuit 34h is mounted may be a rigid substrate, and the connecting portion 34Eg2 electrically and mechanically connected to the first substrate 31 may be a flexible substrate. In this case, the connecting portion 34Eg2 may be made of, for example, a flexible substrate. In this case, no distortion occurs in the second substrate 34Eg.

[0069] In the optical transceiver 30B according to the third embodiment, the countersunk portion 32Bc is provided on the side surface (external wall surface) of the housing 32B facing the y-axis direction, but the countersunk portion may be provided on another external wall surface (for example, the external wall surface facing the positive z-axis direction, i.e., the top surface).The second board and the control board may be attached to the countersunk portion.

[0070] In the above embodiment, the control circuit may be mounted on the first substrate, and in this case, a drive circuit, a processing circuit, or electronic components may be mounted on the second substrate instead of the control circuit.

[0071] Furthermore, for example, in the above-described first embodiment, the connection portion 34g2 of the second substrate 34g is a portion that is electrically and mechanically connected to the first substrate 31, but the second substrate 34g and the first substrate 31 may be electrically connected without going through the connection portion 34g2. In this case, the second substrate 34g and the first substrate 31 may be electrically connected by a conductor such as a bonding wire. Furthermore, the second substrate 34g and the control circuit 34h mounted thereon may be electrically connected to the drive circuit 34c, the processing circuit 34d, and other electronic circuits by a conductor such as a bonding wire, without going through the first substrate 31. This is also true for other embodiments.

[0072] Furthermore, the present invention is not limited to the above-described embodiments. The present invention also includes configurations in which the above-described components are appropriately combined. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments, and various modifications are possible.

[0073] The present invention can be used in an optical transceiver.

[0074] 10: Substrate 10c: Side 20: Switch ASIC 21: Heat sink 21a: Fin 30, 30A, 30B, 30C, 30D: Optical transceiver 31: First substrate 31a: First surface 31b: Second surface 31c: Screw hole 31d: Positioning hole 32, 32A, 32B, 32D: Housing 32Ag: Storage section 32ba, 32Aga: Top wall 32b, 32Bb: First storage section 32Bba: Convex portion 32Bc: Counterbore portion 32a, 32Da: Through hole 32Dc: Second storage section 32ca, 32Dca: Inner wall surface 32bca: Wall surface 32c: Second storage section 32d : Positioning hole 32e : Screw fastening portion 33 : Optical fiber cord with connector 33a : Optical fiber cord 33b : MT connector 34a : Light emitting element 34b : Light receiving element 34c : Drive circuit 34d : Processing circuit 34e : Electronic component 34f : Electrical interface 34g, 34Ag, 34Eg : Second board 34g1, 34Eg1 : Mounting portion 34g2, 34Eg2 : Connection portion 34h : Control circuit 34Ci : Electrical connector 35 : Lens assembly 35a : Lens array 35b, 38 : Positioning pin 36a, 36b : Lower frame 36aa, 36ba : Screw hole 36ab, 36bb : Positioning hole 36ac : Storage portion 37 : Screw member 39, 39B : Heat conductive material 40: Fixing mechanism 100: Switch device 200: Motherboard Ar1, Ar2: Arrows

Claims

1. An optical transceiver comprising: a light-emitting element that outputs light; a light-receiving element that receives light and outputs an electrical signal corresponding to the light; a drive circuit that drives the light-emitting element; a processing circuit that processes the electrical signal from the light-receiving element; a first board on which the light-emitting element, the light-receiving element, the drive circuit, and the processing circuit are mounted; a housing that houses the light-emitting element, the light-receiving element, the drive circuit, and the processing circuit; a control circuit that controls the drive circuit and the processing circuit; a second board having a mounting portion on which the control circuit is mounted and a flexible connecting portion; and an electrical interface provided on the first board that electrically connects the optical transceiver to an external device, wherein the second board is attached to the wall of the housing at the mounting portion.

2. The optical transceiver according to claim 1, wherein the second board is electrically connected to the first board at the connection portion.

3. The optical transceiver according to claim 1, wherein the drive circuit, the processing circuit, and the control circuit are in thermal contact with the housing via a thermally conductive material, and the heat generated by the drive circuit, the processing circuit, and the control circuit is dissipated in the same direction through the housing.

4. The optical transceiver according to claim 1, wherein the wall surface is parallel to or intersects with a first surface of the first substrate on which the drive circuit and the processing circuit are mounted.

5. The optical transceiver according to claim 1, wherein the housing comprises a mounting structure having the wall surface.

6. The optical transceiver according to claim 5, wherein the mounting structure is a groove, recess, hole, or countersink provided in the housing.

7. An optical transceiver as described in claim 1, comprising electronic components mounted on a second surface of the first substrate opposite to the first surface on which the drive circuit and the processing circuit are mounted, and a housing member attached to the second surface for housing the electronic components.

8. The optical transceiver according to claim 1, wherein the housing is made of a material with good thermal conductivity.

9. The optical transceiver according to claim 1, wherein the second substrate is electrically connected to the first substrate by solder, conductive adhesive, anisotropic conductive adhesive, or an electrical connector.

10. The optical transceiver of claim 1, wherein the electrical interface includes a land grid array.

11. The optical transceiver according to claim 1, further comprising a positioning pin that penetrates at least the first substrate and fits into a positioning hole provided in the housing.

12. The optical transceiver according to claim 1, wherein the housing has a positioning hole, and a positioning pin provided in a fixing mechanism that fixes the optical transceiver to a substrate penetrates at least the first substrate and fits into the positioning hole.

13. The optical transceiver according to claim 1, further comprising an optical fiber extending in a direction intersecting the first substrate.

14. An optical communication device comprising: a plurality of optical transceivers according to any one of claims 1 to 13; and an electrical device electrically connected to said plurality of optical transceivers.

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