Optical transmitter module and optical module

Abstract

Provided is an optical transmission module that has a simpler configuration and can be downsized and made faster. The optical transmission module includes: a housing; one or more substrates that are stacked and housed inside of the housing so as to be partially exposed; a light emitter that is housed in the housing and generates an optical signal; an optical functional element that is housed in the housing and performs signal processing on a transmission signal for driving the light emitter; and multiple terminals provided on the one or more substrates so as to extend from the inside to the outside of the housing. A first group of multiple internal terminals are first internal terminals that are connected to electrodes of a high-frequency circuit of an optical functional element; a second group of multiple internal terminals are second internal terminals that are connected to electrodes of a low-frequency circuit of the optical functional element; and in a direction perpendicular to a major surface of the one or more substrates, the length between the upper surfaces of the electrodes of the high-frequency circuit and the upper surfaces of the first internal terminals is less than the length between the upper surfaces of the electrodes of the low-frequency circuit and the upper surfaces of the second internal terminals.

Description

[Technical Field]

[0001] The present invention relates to an optical transmission module and the like. [Background technology]

[0002] In recent years, the performance of optical modules used in optical communication systems has been improving. Along with this improvement in performance, there is a demand for optical modules to be more compact and for their transmission speeds to be higher. Such miniaturization and speed increases must be achieved while satisfying various specifications. For this reason, technologies are being investigated to reduce the size of optical modules and increase their capacity while still satisfying specifications.

[0003] For example, Patent Document 1 discloses a technology for reducing the height of an optical module while ensuring optical coupling between an optical semiconductor element and an optical component. This optical module includes an optical semiconductor element having a first optical axis and an optical component having a second optical axis, and the height of the first optical axis from the bottom surface is made higher than the height of the second optical axis, and an optical axis adjustment section is provided on the side wall to compensate for the heights of the first and second optical axes. This configuration achieves a reduction in the height of the optical module while ensuring optical coupling between the optical semiconductor element and the optical component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-140240 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology described in Patent Document 1 can reduce the height of the optical module, but has the problem of a complex structure due to the provision of an optical axis adjustment section.

[0006] An object of the present invention is to provide an optical transmission module or the like that has a simpler structure and is capable of being made smaller and capable of achieving higher speeds. [Means for solving the problem]

[0007] an optical transmission module according to the present invention comprising: a housing; one or more substrates housed in the housing and stacked inside the housing so as to be partially exposed; a light-emitting unit housed in the housing and generating an optical signal; an optical functional element housed in the housing and performing signal processing of a transmission signal that drives the light-emitting unit; a plurality of terminals provided on the one or more substrates so as to straddle between the outside and the inside of the housing; a plurality of external terminals among the plurality of terminals that are arranged outside the housing; and a plurality of internal terminals among the plurality of terminals that are arranged inside the housing, wherein a first group of the plurality of internal terminals is a first internal terminal connected to an electrode of a high-frequency circuit of the optical functional element, and a second group of the plurality of internal terminals is a second internal terminal connected to an electrode of a low-frequency circuit of the optical functional element, and a length between an upper surface of the electrode of the high-frequency circuit and an upper surface of the first internal terminal is shorter than a length between an upper surface of the electrode of the low-frequency circuit and an upper surface of the second internal terminal. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an optical transmission module or the like that has a simpler structure and is capable of being made smaller and faster. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating an overview of an optical transceiver, which is an example of a device to which an optical module according to a first embodiment of the present invention is applied. [Figure 2] 1 is a schematic plan view showing an example of the configuration of an optical module including an optical transmission module according to a first embodiment of the present invention. [Figure 3] 1 is a schematic plan view showing an example of an optical transmission module according to a first embodiment of the present invention. [Figure 4]1 is a schematic side view showing an example of an optical transmission module according to a first embodiment of the present invention. [Figure 5] 1 is a cross-sectional view showing an example of a connection structure of an optical transmission module according to a first embodiment of the present invention. [Figure 6] FIG. 10 is a schematic plan view showing an example of an optical transmission module according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a schematic plan view showing a part of an optical transmission module according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a schematic side view showing a part of the optical transmission module according to the third embodiment of the present invention. [Figure 9] FIG. 10 is a schematic side view showing a part of the optical transmission module according to the fourth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic side view showing a configuration example of an optical module according to a fifth embodiment of the present invention. [Figure 11] FIG. 10 is an exploded plan view showing an example of an optical module according to a fifth embodiment of the present invention. [Figure 12] FIG. 10 is a schematic plan view showing an example of an optical module according to a fifth embodiment of the present invention. [Figure 13] FIG. 13 is a schematic plan view showing an example of an optical module according to a sixth embodiment of the present invention. [Figure 14] FIG. 13 is a plan view schematically illustrating an example of a flexible substrate used in an optical module according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments described below are limited to technically preferable aspects for carrying out the present invention, but are not intended to limit the scope of the invention. Note that similar components in each drawing are given the same reference numerals, and their description may be omitted.

[0011] (First embodiment) Fig. 1 is a schematic diagram showing an overview of an optical transceiver, which is an example of a device to which an optical module according to a first embodiment of the present invention is applied. Fig. 2 is a schematic plan view showing an example of the configuration of an optical module according to the first embodiment of the present invention. Fig. 3 is a schematic plan view showing an example of the configuration of an optical transmission module 1000 incorporated in an optical module 10000.

[0012] 1, the optical transceiver 1 has a housing 2 that houses the optical module 10000 and a connector 3 to which an optical line is connected. Also, although not shown, a connector is disposed on the opposite side of the housing 2 from the connector 3 for electrically connecting the optical transceiver 1 to an electronic device.

[0013] 2 is a schematic plan view showing an example of the configuration of an optical module 10000 according to the first embodiment of the present invention. The optical module 10000 includes an optical transmitting module 1000, an optical receiving module 2000, a circuit board 3000, and a flexible substrate 4000. Here, the flexible substrate 4000 is also called an FPC (Flexible Printed Circuit). The optical module 10000 may be provided with a transmitting sleeve 5000 that connects to a connector on the light output side of the optical transmitting module 1000, and a receiving sleeve 6000 that connects to a connector on the light input side of the optical receiving module 2000.

[0014] A substrate 1100 protrudes from one end of the optical transmitting module 1000, and a flexible substrate 4000 electrically connects the terminal 1110 to the circuit board 3000. Although not shown, the optical receiving module 2000 is also electrically connected to the circuit board 3000.

[0015] Fig. 3 is a schematic plan view showing an example of the configuration of the optical transmission module 1000. The top surface of the optical transmission module 1000 is covered with a lid during use, but Fig. 3 shows the state without the lid. Fig. 4 is a schematic side view showing an example of the optical transmission module according to the first embodiment of the present invention.

[0016] The optical transmission module 1000 includes a substrate 1100, a housing 1200, an optical functional element 1300, a light emitting unit 1400, an optical multiplexer 1500, a temperature adjusting element 1700, and a plurality of terminals 1110. Note that the optical multiplexer 1500 and the temperature adjusting element 1700 are not essential components of the present invention.

[0017] 3 and 4, the substrate 1100 is housed inside the housing 1200 so that a portion of the substrate 1100 is exposed. A plurality of terminals 1110 are formed on the substrate 1100. The substrate 1100 is inserted into the housing 1200 from one side of the housing 1200.

[0018] 3 and 4, the substrate 1100 is a laminate of a first substrate 1100a and a second substrate 1100b. If the first substrate 1100a and the second substrate 1100b have different planar shapes, flat portions of different heights are formed in the direction perpendicular to the surface of the substrate 1100. Here, the first substrate 1100a and the second substrate 1100b correspond to one or more substrates. That is, the first substrate 1100a and the second substrate 1100b are stacked and housed inside the housing 1200 so that a portion of each is exposed.

[0019] A portion of the substrate 1100 arranged inside the housing 1200 (second substrate 1100b in FIG. 5) is formed so as to fit along the inner surface of the housing 1200. That is, the portion of the substrate 1100 arranged inside the housing 1200 is, in principle, hollowed out in the center to form a U-shape (or the letter C) in order to secure space for accommodating elements and the like inside.

[0020] The housing 1200 is formed in a box shape. The housing 1200 houses electronic components such as the optical functional element 1300, the light emitting unit 1400, and the optical multiplexer 1500, as well as parts of the first substrate 1100a and the second substrate 1100b. For example, a Kovar alloy is used as the material for the housing 1200, and a Cu alloy with good thermal conductivity, such as CuW or CuMo alloy, is used for the surface on which the optical module is installed.

[0021] The optical functional element 1300 is housed inside the housing 1200. The optical functional element 1300 has a function of controlling the oscillation wavelength and a function of optical modulation that modulates an optical signal. The optical transmission module 1000, for example, uses the optical functional element 1300 and the light-emitting unit 1400 to perform laser oscillation at a predetermined wavelength in response to a control signal input from the terminal 1110. A high-frequency signal from outside the housing is input via the terminal 1110, and the laser light is modulated to generate an optically modulated signal. Note that the above operation may cause losses due to the modulator. For this reason, in the example of FIG. 3, two light-emitting units 1400 are provided to compensate for losses due to the modulator function and maintain the optical output within a predetermined range. A specific example of the optical functional element 1300 is a silicon photonics element in which functions such as an optical waveguide, an optical modulator, and an optical receiving element are integrated on a silicon substrate.

[0022] The optical multiplexer 1500 is housed inside the housing 1200. The optical multiplexer 1500 multiplexes the multiple light beams emitted from the multiple blocks of the light emitting section 1400, and emits the multiple light beams toward the window 1210.

[0023] The temperature adjustment element 1700 is provided on the bottom side of the optical functional element 1300 and the light-emitting section 1400. The temperature adjustment element is, for example, a thermoelectric element generally called a TEC (Thermo-Electric Cooler), which is an element whose temperature is controlled by electrical operation, and is equipped with, for example, a Peltier element. By the above operation, the temperature adjustment element 1700 adjusts the temperature of the optical functional element 1300 and the light-emitting section 1400.

[0024] The multiple terminals 1110 are provided on the first substrate 1100a and the second substrate 1100b so as to straddle the outside and inside of the housing 1200. Of the multiple terminals 1110, the portions outside the housing 1200 are referred to as external terminals 1120, and the portions inside the housing 1200 are referred to as internal terminals 1130. In other words, the multiple external terminals 1120 are the multiple terminals 1110 that are arranged outside the housing 1200. The multiple internal terminals 1130 are the multiple terminals 1110 that are arranged inside the housing 1200.

[0025] The internal terminals 1130 can be connected to components such as the optical functional element 1300 and the light-emitting unit 1400 by, for example, wires 1600. The internal terminals 1130 are divided into a first group of first internal terminals 1130a connected to the high-frequency circuit 1310 and a second group of second internal terminals 1130b connected to the low-frequency circuit 1320. That is, the first group of the multiple internal terminals 1130 is the first internal terminals 1130a connected to electrodes of the high-frequency circuit 1310 of the optical functional element. The second group of the multiple internal terminals 1130 is the second internal terminals 1130b connected to electrodes of the low-frequency circuit 1320 of the optical functional element. In the following description, high frequency may be referred to as RF (Radio Frequency).

[0026] Fig. 5 is a cross-sectional view showing an example of a connection structure of the optical transmission module according to the first embodiment of the present invention. Fig. 5 shows a connection portion made by a wire 1600 in a cross section taken along line AA' in Fig. 3. In the optical transmission module 1000, the first internal terminal 1130a and an electrode of the high-frequency circuit 1310 are connected by the wire 1600, and the second internal terminal 1130b and an electrode of the low-frequency circuit 1320 are connected by the wire 1600. The first internal terminal 1130a is disposed on the first substrate 1100a, and the second internal terminal 1130b is disposed on the second substrate 1100b.

[0027] As shown in FIG. 5, in a direction perpendicular to the main surface of the substrate 1100, the length between the upper surface of the electrode 1310a of the high-frequency circuit 1310 and the upper surface of the first internal terminal 1130a is L1. The length between the upper surface of the electrode 1320a of the low-frequency circuit 1320 and the upper surface of the second internal terminal 1130b is L2. L1 is smaller than L2. Note that L1 may be zero. In other words, the upper surfaces of the electrodes of the high-frequency circuit 1310 and the first internal terminal 1130a may be flush with each other in a direction perpendicular to the main surface of the substrate 1100.

[0028] As described above, the length L2 between the upper surface of the electrode of the low-frequency circuit 1320 and the second internal terminal 1130b is increased in order to increase the thermal resistance therebetween. Increasing L2 allows the wire 1600 connecting the electrode of the low-frequency circuit 1320 and the second internal terminal 1130b to be longer. This configuration is used because the temperature of the environment in which the optical transmitting module 1000 is placed is less likely to be transmitted to the optical functional element 1300 and the light-emitting unit 1400. Generally, to ensure stable operation of the optical functional element 1300 and the light-emitting unit 1400, their temperatures must be maintained within a predetermined range. However, the temperature of the environment surrounding the optical transmitting module 1000 may fluctuate beyond this predetermined range. In such cases, the temperature adjustment element 1700 operates to maintain the temperatures of the optical functional element 1300 and the light-emitting unit 1400 within the predetermined range. At this time, as described above, by increasing the thermal resistance between the second internal terminal 1130b and the low-frequency circuit 1320, it becomes easier to maintain the temperatures of the optical functional element 1300 and the light-emitting part 1400 within a predetermined range. In addition, the power consumption of the temperature adjustment element 1700 can be reduced.

[0029] On the other hand, the length L1 between the upper surface of the electrode of the high-frequency circuit 1310 and the upper surface of the first internal terminal 1130a is reduced in order to shorten the first wire 1600a connecting them. This is because if the first wire 1600a connecting the high-frequency circuit 1310 and the first internal terminal 1130a is longer, the impedance increases, making it difficult to stably transmit high-frequency signals. On the other hand, as mentioned above, shortening the wire 1600 increases the heat conduction from the environment to the optical functional element 1300 and the light-emitting unit 1400. However, the high-frequency circuit 1310 is configured as described above because signal stability is prioritized.

[0030] The optical transmission module 1000 of the first embodiment has been described above.

[0031] The optical transmission module 1000 has a substrate 1100, a housing 1200, one or more substrates 1100a and 1100b, an optical functional element 1300, and a light-emitting unit 1400. The one or more substrates 1100a and 1100b are stacked and housed inside the housing 1200 so that a portion of each is exposed. The light-emitting unit 1400 is housed in the housing 1200 and generates an optical signal. The optical functional element 1300 is housed in the housing 1200 and performs signal processing of a transmission signal that drives the light-emitting unit 1400. A plurality of terminals 1110 are provided on one or more substrates (1100a and 1100b) so as to straddle the outside and inside of the housing 1200. The substrate 1100 has, among the plurality of terminals 1110, a plurality of external terminals 1120 that are arranged outside the housing 1200, and a plurality of internal terminals 1130 that are arranged inside the housing 1200. A first group of the plurality of internal terminals 1130 is first internal terminals 1130a that are connected to electrodes of a high-frequency circuit 1310 of the optical functional element 1300. A second group of the plurality of internal terminals 1130 is second internal terminals 1130b that are connected to electrodes of a low-frequency circuit 1320 of the optical functional element 1300. In a direction perpendicular to the main surface of one or more substrates 1100, the length between the upper surface of the electrode of the high-frequency circuit 1310 and the upper surface of the first internal terminal 1130a is shorter than the length between the upper surface of the electrode of the low-frequency circuit and the upper surface of the second internal terminal.

[0032] In the configuration of the optical transmission module 1000 described above, the length L1 between the upper surface of the electrode of the high-frequency circuit 1310 and the first internal terminal 1130a is short in the direction perpendicular to the main surfaces of the one or more substrates 1100a and 1100b, allowing the length of the wire 1600 connecting them to each other to be shortened. This reduces impedance and enables stable transmission of high-frequency signals. Meanwhile, the length L2 between the upper surface of the electrode of the low-frequency circuit 1320 and the second internal terminal is long in the direction perpendicular to the main surfaces of the one or more substrates 1100. This allows the length of the wire 1600 connecting them to each other to be long. The long length of the wire 1600 increases thermal resistance, making it more difficult for the environmental temperature outside the housing 1200 to be transmitted to the optical functional element 1300 and the light-emitting unit 1400. As a result, it becomes easier to maintain the temperatures of the optical functional element 1300 and the light-emitting unit 1400 within a predetermined range.

[0033] (Second embodiment) FIG. 6 is a schematic plan view showing an example of an optical transmission module 1001 according to a second embodiment of the present invention. The configuration of the second optical transmission module 1001 is substantially the same as that of the optical transmission module according to the first embodiment. However, the second optical transmission module 1001 differs in that a region of one or more substrates 1100 where a plurality of internal terminals 1130 are not provided has a recess 1140 provided so as to be spaced apart from electronic components (such as the light-emitting unit 1400 and the optical functional element 1300) provided inside the housing 1200. In the region where the recess 1140 is formed, the distance between the substrate 1100 and the elements (such as the light-emitting unit 1400 and the optical functional element 1300) housed in the housing 1200 is greater than in the region where the recess 1140 is not formed. As a result, the environmental temperature outside the optical transmission module 1000 is less likely to be transmitted to the elements housed in the housing 1200, making it easier to maintain the temperatures of the elements (such as the light-emitting unit 1400 and the optical functional element 1300) within a predetermined range.

[0034] The above-described structure in which the recess 1140 is formed in the substrate 1100 can be applied to other structures besides the structure in the first embodiment in which L1 is smaller than L2.

[0035] The optical transmission module 1001 of the second embodiment has been described above.

[0036] In the optical transmitting module 1001, a recess is provided in an area of one or more substrates 1100 where a plurality of internal terminals 1130 are not provided, so as to separate the substrate 1100 from the electronic components housed inside the housing 1200. The recess 1140 increases the distance between the substrate 1100 and the elements housed in the housing 1200 (such as the light-emitting unit 1400 and the optical functional element 1300). As a result, the environmental temperature outside the optical transmitting module 1000 is less likely to be transmitted to the elements housed in the housing 1200, making it easier to maintain the temperatures of the elements (such as the light-emitting unit 1400 and the optical functional element 1300) within a predetermined range. As a result, the elements such as the light-emitting unit 1400 and the optical functional element 1300 can operate stably.

[0037] (Third embodiment) In this embodiment, details of the optical functional element 1300 and the light emitting unit 1400 built into the optical transmission module 1000 of the first embodiment and the optical transmission module 1001 of the second embodiment will be described. Fig. 7 is a schematic plan view showing a part of the optical transmission module of the third embodiment of the present invention. Fig. 8 is a schematic side view showing a part of the optical transmission module of the third embodiment of the present invention.

[0038] As shown in FIGS. 7 and 8 , in the light-emitting unit 1400, a light-emitting element 1410 is mounted on a block-shaped chip carrier 1420. The light-emitting element 1410 is, for example, a laser diode. Although FIGS. 7 and 8 show two light-emitting elements 1410, three or more light-emitting elements 1410 may be used. The bonding surface 1430 of the chip carrier 1420 and the optical functional element 1300 is bonded with an ultraviolet curing resin 1440. Although not shown in FIGS. 7 and 8 , the optical functional element 1300 and the chip carrier 1420 each have a waveguide, and the waveguides are positioned and then bonded. Furthermore, as shown in FIG. 7 , the chip carrier 1420 has a constricted portion 1450 on the side where the bonding surface 1430 of the chip carrier 1420 and the optical functional element 1300 is formed. The provision of the constricted portion 1450 makes it easier for light that cures the ultraviolet curing resin 1440 to reach the interior of the ultraviolet curing resin 1440. Therefore, the chip carrier 1420 and the optical functional element 1300 can be positioned with high precision and firmly bonded together.

[0039] The above-described configuration in which the chip carrier 1420 has the constricted portion 1450 can be applied regardless of the first or second embodiment. In other words, as long as there is a configuration in which the chip carrier 1420 and the optical functional element 1300 are bonded with the ultraviolet curing resin 1440, it can be applied to other optical transmission modules.

[0040] An example of the configuration of part of the optical transmission module 1000 of the third embodiment has been described above.

[0041] The light emitting unit 1400 of the optical transmission module 1000 of this embodiment has a configuration in which a light emitting element 1410 is mounted on a block-shaped chip carrier 1420, and the optical functional element 1300 has a configuration in which a signal processing IC 1330 is mounted on the block-shaped optical functional element 1300. The chip carrier 1420 and the optical functional element 1300 are bonded together with an ultraviolet curing resin 1440. Furthermore, the chip carrier 1420 has a constricted portion 1450 on the side where the bonding surface 1430 between the chip carrier 1420 and the optical functional element 1300 is formed. By providing the constricted portion 1450 on the chip carrier 1420, it becomes easier for light that cures the ultraviolet curing resin 1440 to reach the inside of the ultraviolet curing resin 1440. Therefore, the chip carrier 1420 and the optical functional element 1300 can be positioned with high precision and firmly bonded together.

[0042] (Fourth embodiment) In this embodiment, a configuration for adjusting the temperature of a portion of the optical transmission module of the third embodiment will be described. Fig. 9 is a schematic side view showing a portion of the optical transmission module of the fourth embodiment of the present invention. As shown in Fig. 9, the optical transmission module 1000 of this embodiment has a heat transfer plate 1710 between the optical functional element 1300, the chip carrier 1420, and the temperature adjustment element 1700.

[0043] The heat transfer plate 1710 is provided inside the housing 1200, and the chip carrier 1420 and the optical functional element 1300 are attached to it.

[0044] The temperature adjustment element 1700 is provided inside the housing 1200, and has a heat transfer plate 1710 attached thereto, and adjusts the temperature of the heat transfer plate 1710.

[0045] The area of the heat transfer plate is The area of the surface of the chip carrier and the optical functional element that is in contact with the heat transfer plate is larger than the area of the surface of the chip carrier and the optical functional element that is in contact with the heat transfer plate. Here, the chip carrier 1420 and the optical functional element 1300 are thermally connected to the temperature adjustment element 1700 via a heat transfer plate 1710. The area of the heat transfer plate 1710 is larger than the area of the surfaces of the chip carrier 1420 and the optical functional element 1300 that are in contact with the heat transfer plate 1710.

[0046] The temperature adjustment element 1700 is, for example, what is generally called a TEC (Thermo-Electric Cooler), and controls the temperature by electrical operation. As described above, the area of the heat transfer plate 1710 is larger than the area of the surface where the chip carrier 1420 and the optical functional element 1300 are in contact with the heat transfer plate 1710. The material of the heat transfer plate 1710 can be, for example, aluminum nitride or a copper alloy. By using such a heat transfer plate 1710, heat conduction in the direction along the bottom surfaces of the chip carrier 1420 and the optical functional element 1300 is increased, making it easier to adjust the temperature by the temperature adjustment element 1700.

[0047] The configuration in which the heat transfer plate 1710 is provided can be applied regardless of the configuration in which the chip carrier 1420 and the optical functional element 1300 are bonded with the ultraviolet curing resin 1440 as in the third embodiment. That is, it is also possible to configure at least one of the chip carrier 1420 and the optical functional element 1300 to be connected to the temperature adjustment element 1700 via the heat transfer plate 1710 having an area larger than the bottom surface of the chip carrier 1420 and the optical functional element 1300. Furthermore, it is also possible to configure other elements constituting the optical transmitting module 1000 to be in contact with the heat transfer plate 1710 having an area larger than the bottom surface of the chip carrier 1420 and the optical functional element 1300.

[0048] The configuration of part of the optical transmission module of the fourth embodiment has been described above.

[0049] The optical transmission module 1000 of this embodiment has a heat transfer plate 1710 and a temperature adjustment element 1700. The heat transfer plate 1710 is provided inside the housing 1200, and the chip carrier 1420 and the optical functional element 1300 are attached to the heat transfer plate 1710. The temperature adjustment element 1700 is provided inside the housing 1200, and the heat transfer plate 1710 is attached to adjust the temperature of the heat transfer plate 1710. The chip carrier 1420 and the optical functional element 1300 are thermally connected to the temperature adjustment element via the heat transfer plate 1710. The area of the heat transfer plate 1710 is larger than the area of the surfaces of the chip carrier 1420 and the optical functional element 1300 that are in contact with the heat transfer plate 1710. By using such a heat transfer plate 1710, heat conduction in the direction along the bottom surfaces of the chip carrier 1420 and the optical functional element 1300 is increased, making it easier to adjust the temperature by the temperature adjustment element 1700.

[0050] (Fifth embodiment) In this embodiment, a configuration example of a circuit board 3000 connected to the optical transmission module 1000 in the optical module 10000 of FIG. 2 by a flexible substrate 4000 will be described. Fig. 10 is a side view showing a configuration example of an optical module according to a fifth embodiment of the present invention. Fig. 11 is an exploded plan view showing an example of an optical module according to the fifth embodiment of the present invention. Fig. 12 is a plan view showing an example of an optical module according to the fifth embodiment of the present invention.

[0051] The circuit board 3000 is composed of a first circuit board 3000a and a second circuit board 3000b. In the following explanation, an example in which there are two circuit boards 3000 will be described, but the same can be applied to a case in which there are three or more circuit boards.

[0052] The circuit board 3000 has a first circuit board 3000a and a second circuit board 3000b that are stacked with a gap between their main surfaces. The external terminal 1120 of the optical transmission module 1000 and the second circuit board 3000b are electrically connected by a flexible substrate 4000. The circuit board 3000 further has a holding member 8000 that is attached to the side end of the plurality of circuit boards 3000 and holds each of the plurality of circuit boards 3000 while separating the main surfaces of the plurality of circuit boards 3000.

[0053] 11, first circuit board 3000a is provided with notches 3001a and 3002a into which holding member 8000 is fitted. Then, holding member 8000 is fitted into notches 3001a and 3002a from the outside of the side end portions, respectively, resulting in the state shown in FIG.

[0054] With the above configuration, the main surface of first circuit board 3000a and the main surface of second circuit board 3000b can be arranged to overlap at a predetermined distance. In this case, because holding members 8000 are arranged on the side edges of first circuit boards 3000a and 4000b, a wide area can be secured for mounting components on first circuit boards 3000a and 4000b.

[0055] The above configuration can also be applied to optical modules including optical transmission modules other than the optical transmission modules 1000 and 1001 of the first to fourth embodiments. In this case, the optical module only needs to include an optical transmission module, its terminals, a plurality of circuit boards, and a flexible substrate connecting the terminals to at least one of the circuit boards.

[0056] A partial configuration of the optical module according to the fifth embodiment has been described above.

[0057] A portion of the optical module 10000 of this embodiment includes a plurality of circuit boards 3000 stacked with a gap between their main surfaces, and a flexible substrate that electrically connects the external terminal 1120 of the optical transmission module 1000 to at least one of the plurality of circuit boards. The optical module 10000 further includes a holding member 8000 attached to the side edges of the plurality of circuit boards 3000 and that holds each of the plurality of circuit boards 3000 while separating the main surfaces of the plurality of circuit boards 3000. In the above configuration, since the holding member 8000 is disposed at the side edges of the circuit boards 3000, a larger area can be provided on the circuit board 3000 for mounting components.

[0058] Furthermore, at least one of the multiple circuit boards 3000 in the optical module 10000 has cutouts 3001a, 3002a into which the holding member 8000 fits. Since the cutouts 3001a, 3002a are provided and the holding member 8000 fits, the holding member 8000 can be held stably.

[0059] (Sixth embodiment) In this embodiment, a flexible substrate 4100, which is a modification of the flexible substrate 4000 that connects the external terminal 1120 of the optical transmission module 1000 and the flexible substrate 4000, will be described. FIG. 13 is a plan view schematically illustrating an example of an optical module according to a sixth embodiment of the present invention. The flexible substrate 4100 has a plurality of first terminals arranged at one end and a plurality of second terminals arranged at the other end that are orthogonal to each other. The circuit substrate 3000 has a shape that allows the flexible substrate 4100 to be passed from one main surface to the other main surface of the circuit substrate 3000. With this configuration, the connection portion between the circuit substrate 3000 and the flexible substrate 4100 can be located, for example, on the top surface of the optical module 10000. This can facilitate, for example, soldering or other operations for connection.

[0060] The above configuration can also be applied to optical modules including optical transmission modules other than the optical transmission modules 1000 and 1001 of the first to fourth embodiments, and optical modules other than those of the fifth embodiment. In this case, the optical module only needs to include an optical transmission module, its terminals, a circuit board, and a flexible board connecting the terminals and the circuit board.

[0061] The above describes an example of the configuration of the optical module 10000 according to the sixth embodiment.

[0062] In the optical module 10000, a plurality of first terminals arranged at one end of the flexible substrate 4000 and a plurality of second terminals arranged at the other end of the flexible substrate 4000 are arranged so as to intersect at right angles. By using a flexible substrate having such a configuration, the degree of freedom in the layout when connecting the flexible substrate 4000 and the circuit board 3000 is increased, and it is possible to select a configuration that allows for good workability in the connection work, for example.

[0063] (Seventh embodiment) In this embodiment, a modified example of the flexible substrate 4000 used in the fifth and sixth embodiments will be described. FIG. 14 is a plan view showing an example of a flexible substrate used in the optical module of the seventh embodiment of the present invention. The flexible substrate 4200 of this embodiment has a configuration in which a plurality of wirings 4220 are arranged in parallel on a base material 4210. The flexible substrate 4200 has a plurality of through holes 4240 between adjacent wirings and a plurality of reinforcing materials 4230 filled in each of the plurality of through holes 4240, and the plurality of reinforcing materials 4230 are arranged in a staggered pattern. Furthermore, each wiring 4220 is not linear but has a meandering shape so that the distance between each wiring 4220 and each reinforcing material 4230 is equal to or greater than a predetermined value.

[0064] The reinforcing material 4230 is, for example, a metal filled in through holes 4240 provided in the base material 4210 between the wirings 4220. By providing the reinforcing material 4230, it is possible to improve the mechanical strength of the flexible substrate 4200, such as the shear strength and tensile strength. Furthermore, by arranging the reinforcing material 4230 in a staggered pattern, it is possible to arrange the reinforcing material 4230 at a higher density per unit area than when the reinforcing material 4230 is arranged linearly. Therefore, it is possible to improve the mechanical strength more than when the reinforcing material 4230 is arranged linearly.

[0065] The above configuration can also be applied to optical modules including optical transmission modules other than the optical transmission modules 1000 and 1001 of the first to fourth embodiments, and optical modules other than those of the fifth and sixth embodiments. In this case, the optical module only needs to include an optical transmission module, its terminals, a circuit board, and a flexible board connecting the terminals and the circuit board.

[0066] An example of the flexible substrate 4200 used in the optical module of the seventh embodiment has been described above. The flexible substrate 4200 has a plurality of through-holes 4240 between adjacent wirings, and a plurality of reinforcing materials 4230 filled in each of the through-holes 4240. The reinforcing materials 4230 are arranged in a staggered pattern. This staggered arrangement allows the reinforcing materials 4230 to be arranged at a high density per unit area. This allows for greater mechanical strength than when the reinforcing materials are arranged in a linear pattern.

[0067] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) The housing and One or more substrates stacked and accommodated inside the housing so that a portion of the substrate is exposed; a light emitting unit accommodated in the housing and configured to generate an optical signal; an optical functional element that is housed in the housing and performs signal processing of a transmission signal that drives the light-emitting unit; a plurality of terminals provided on the one or more substrates so as to straddle the exterior and interior of the housing; Among the plurality of terminals, a plurality of external terminals are arranged outside the housing; and Among the plurality of terminals, a plurality of internal terminals are arranged inside the housing, a first group of the plurality of internal terminals is a first group of internal terminals connected to electrodes of a high-frequency circuit of the optical functional element; a second group of the plurality of internal terminals is a second group of internal terminals connected to electrodes of a low-frequency circuit of the optical functional element; In a direction perpendicular to the main surface of the one or more substrates, the length between the upper surface of the electrode of the high-frequency circuit and the upper surface of the first internal terminal is shorter than the length between the upper surface of the electrode of the low-frequency circuit and the upper surface of the second internal terminal. An optical transmission module characterized by: (Appendix 2) a recess provided in an area of the one or more substrates where the plurality of internal terminals are not provided, the recess being spaced apart from an electronic component provided inside the housing; 2. The optical transmission module according to claim 1, (Appendix 3) an electrode of the high-frequency circuit and the first internal terminal are connected by a wire; The electrode of the low-frequency circuit and the second internal terminal are connected by a wire. 3. The optical transmission module according to claim 1 or 2. (Appendix 4) the light-emitting unit has a configuration in which a light-emitting element is mounted on a block-shaped chip carrier, the chip carrier and the optical functional element are bonded together by an ultraviolet curing resin; The chip carrier has a constricted portion on the side where the bonding surface between the chip carrier and the optical functional element is formed. 4. The optical transmission module according to claim 1, wherein: (Appendix 5) a heat transfer plate provided inside the housing and on which the chip carrier and the optical functional element are attached; a temperature adjusting element provided inside the housing, to which the heat transfer plate is attached, for adjusting the temperature of the heat transfer plate; the chip carrier and the optical functional element are thermally connected to a temperature adjusting element via the heat transfer plate; The area of the heat transfer plate is The area of the surface of the chip carrier and the optical functional element that is in contact with the heat transfer plate is larger than the area of the surface of the chip carrier and the optical functional element that is in contact with the heat transfer plate. 5. The optical transmission module according to claim 4, (Appendix 6) an optical transmission module according to any one of Supplementary Notes 1 to 5; a plurality of circuit boards arranged such that their main surfaces are stacked with a gap between them; a flexible substrate that electrically connects the external terminal of the optical transmission module to at least one of the plurality of circuit boards; a holding member attached to a side end of the plurality of circuit boards and configured to hold each of the plurality of circuit boards while separating the main surfaces of the plurality of circuit boards from each other; An optical module comprising: (Appendix 7) At least one of the plurality of circuit boards The holding member has a notch portion into which the holding member fits. 7. The optical module according to claim 6, (Appendix 8) a plurality of first terminals arranged at one end of the flexible substrate; a plurality of second terminals arranged on the other end of the flexible substrate, are arranged perpendicular to each other 8. The optical module according to claim 6 or 7. (Appendix 9) The flexible substrate comprises: a plurality of through holes between adjacent wirings; a plurality of reinforcing materials filled in each of the plurality of through holes; The plurality of reinforcing members are arranged in a staggered pattern. 9. The optical module according to claim 6, wherein: (Appendix 10) The housing and One or more substrates stacked and accommodated inside the housing so that a portion of the substrate is exposed; a light emitting unit housed in the housing and generating an optical signal; an optical functional element that is housed in the housing and performs signal processing of a transmission signal that drives the light-emitting unit; a plurality of terminals provided on the one or more substrates so as to straddle the exterior and interior of the housing; Among the plurality of terminals, a plurality of external terminals are arranged outside the housing; and Among the plurality of terminals, a plurality of internal terminals are arranged inside the housing, a first group of the plurality of internal terminals is a first group of internal terminals connected to electrodes of a high-frequency circuit of the optical functional element; a second group of the plurality of internal terminals is a second group of internal terminals connected to electrodes of a low-frequency circuit of the optical functional element; a recess provided in an area of the one or more substrates where the plurality of internal terminals are not provided, the recess being spaced apart from an electronic component provided inside the housing; An optical transmission module characterized by: (Appendix 11) a light emitting unit that outputs light for transmitting an optical signal; an optical functional element for controlling the light-emitting unit; the light-emitting unit has a configuration in which a light-emitting element is mounted on a block-shaped chip carrier, the chip carrier and the optical functional element are bonded together by an ultraviolet curing resin; The chip carrier has a constricted portion on the side where the bonding surface between the chip carrier and the optical functional element is formed. An optical transmission module characterized by: (Appendix 12) an optical transmission module for transmitting an optical signal; a plurality of circuit boards arranged such that their main surfaces are stacked with a gap between them; a flexible substrate that electrically connects the external terminal of the optical transmission module to at least one of the plurality of circuit boards; a holding member that holds each of the plurality of circuit boards while separating the main surfaces of the plurality of circuit boards; An optical module comprising:

[0068] The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above-described embodiment. In other words, the present invention can be applied in various aspects that can be understood by a person skilled in the art within the scope of the present invention. [Explanation of symbols]

[0069] 1 Optical transceiver 2. Housing 3 Connectors 1000, 1001 Optical Transmitter Module 1100 board 1110 terminal 1120 External terminal 1130 Internal terminal 1140 recess 1200 cabinet 1300 Optical Functional Elements 1310 High Frequency Circuits 1320 Low Frequency Circuit 1400 Light-emitting part 1600 wire 1700 Temperature control element 1710 Heat transfer plate 2000 Optical Receiver Module 3000 Circuit Boards 4000 flexible substrate 5000 Transmitter Sleeve 6000 Receiver Sleeve 8000 Retaining member 10000 Optical Module

Claims

1. The housing and one or more substrates stacked and accommodated inside the housing so that a portion of the substrate is exposed; a light emitting unit housed in the housing and generating an optical signal; an optical functional element that is housed in the housing and performs signal processing of a transmission signal that drives the light-emitting unit; a plurality of terminals provided on the one or more substrates so as to straddle the exterior and interior of the housing; Among the plurality of terminals, a plurality of external terminals are arranged outside the housing; and Among the plurality of terminals, a plurality of internal terminals are arranged inside the housing, a first group of the plurality of internal terminals is a first group of internal terminals connected to electrodes of a high-frequency circuit of the optical functional element; a second group of the plurality of internal terminals is a second group of internal terminals connected to electrodes of a low-frequency circuit of the optical functional element; In a direction perpendicular to the main surface of the one or more substrates, the length between the upper surface of the electrode of the high-frequency circuit and the upper surface of the first internal terminal is shorter than the length between the upper surface of the electrode of the low-frequency circuit and the upper surface of the second internal terminal. An optical transmission module characterized by:

2. a recess provided in an area of the one or more substrates where the plurality of internal terminals are not provided, the recess being spaced apart from an electronic component provided inside the housing; 2. The optical transmission module according to claim 1.

3. the electrode of the high-frequency circuit and the first internal terminal are connected by a wire; the electrode of the low-frequency circuit and the second internal terminal are connected by a wire; 3. The optical transmission module according to claim 1, wherein the optical transmission module is a casing.

4. the light-emitting unit has a configuration in which a light-emitting element is mounted on a block-shaped chip carrier, the chip carrier and the optical functional element are bonded together by an ultraviolet curing resin; The chip carrier has a constricted portion on the side where the bonding surface between the chip carrier and the optical functional element is formed.

4. The optical transmission module according to claim 1, wherein the optical transmission module is a semiconductor integrated circuit.

5. a heat transfer plate provided inside the housing and on which the chip carrier and the optical functional element are attached; a temperature adjusting element provided inside the housing, to which the heat transfer plate is attached, for adjusting the temperature of the heat transfer plate; the chip carrier and the optical functional element are thermally connected to a temperature adjusting element via the heat transfer plate; The area of the heat transfer plate is The area of the surface of the chip carrier and the optical functional element that is in contact with the heat transfer plate is larger than the area of the surface of the chip carrier and the optical functional element that is in contact with the heat transfer plate.

5. The optical transmission module according to claim 4.

6. an optical transmission module according to any one of claims 1 to 5; a plurality of circuit boards arranged such that their main surfaces are stacked with a gap between them; a flexible substrate that electrically connects the external terminal of the optical transmission module to at least one of the plurality of circuit boards; a holding member attached to a side end of the plurality of circuit boards and configured to hold each of the plurality of circuit boards while separating the main surfaces of the plurality of circuit boards from each other; An optical module comprising:

7. At least one of the plurality of circuit boards The holding member has a notch portion into which the holding member fits.

7. The optical module according to claim 6.

8. a plurality of first terminals arranged at one end of the flexible substrate; a plurality of second terminals arranged on the other end of the flexible substrate, are arranged perpendicular to each other 8. The optical module according to claim 6, wherein the optical module is a semiconductor laser.

9. The flexible substrate comprises: a plurality of through holes between adjacent wirings; a plurality of reinforcing materials filled in each of the plurality of through holes; The plurality of reinforcing members are arranged in a staggered pattern.

9. The optical module according to claim 6, wherein the optical module is a semiconductor integrated circuit.

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