Optical semiconductor device

Abstract

A first metal block (3) and a temperature control module (4) are mounted on an upper surface of the metal tube base (1). A second metal block (5) is mounted on the temperature control module (4). First and second dielectric substrates (6, 7) are mounted on side surfaces of the first and second metal blocks (3, 5), respectively. First and second signal lines (8, 10) are formed on the first and second dielectric substrates (6, 7), respectively. A semiconductor light modulating element (13) is mounted on the second dielectric substrate (7). A lens cover (19) is joined to the upper surface of the metal tube base (1), is electrically connected to the metal tube base (1), and hermetically seals the semiconductor light modulating element (13) and the like. The minimum distance between the first metal block (3) and the inner wall of the lens cover (19) is less than 0.37 mm. The minimum distance between the second metal block (5) and the inner wall of the lens cover (19) is less than 1.36 mm.

Description

Technical Field

[0001] This disclosure relates to an optical semiconductor device in which components such as semiconductor optical modulation elements are hermetically sealed with a lens cover. Background Technology

[0002] In mobile communication systems, the widespread adoption of mobile terminals and the cloudification of information have led to a dramatic increase in data communication volume. This necessitates larger-capacity optical communication systems and optical communication equipment capable of high-speed, high-capacity signal transmission. As a semiconductor optical integrated element capable of high-speed communication, an EML (Electro-absorption Modulator-integrated Laser) that integrates an Electro-absorption Modulator (EAM) and a Distributed Feedback Laser Diode (DFB-LD) can be used.

[0003] An optical semiconductor device is proposed, wherein a first metal block and a temperature control module are mounted on a metal socket, a second metal block is mounted on the temperature control module, a first and a second dielectric substrate are mounted on the sides of the first and second metal blocks respectively, and a semiconductor optical modulation element is mounted on the second dielectric substrate (for example, see Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2011-197360

[0005] If a lens cover is installed in the device described in Patent Document 1, resonance occurs, the frequency band is limited, and a good optical waveform cannot be obtained. As a solution, increasing the size of the lens cover is considered to shift the resonant point to the high-frequency side. However, due to the miniaturization requirements in CAN packaging, it is not possible to increase the size of the lens cover. Summary of the Invention

[0006] This disclosure was made to solve the aforementioned problems, and its purpose is to obtain an optical semiconductor device that can obtain a good optical waveform without increasing the size of the lens cover.

[0007] The optical semiconductor device disclosed herein is characterized by comprising: a metal socket; lead pins penetrating the metal socket; a first metal block mounted on the upper surface of the metal socket; a first dielectric substrate mounted on the side of the first metal block; a first signal line formed on the first dielectric substrate; a temperature control module mounted on the upper surface of the metal socket; a second metal block mounted on the temperature control module; a second dielectric substrate mounted on the side of the second metal block; a second signal line formed on the second dielectric substrate; a semiconductor optical modulation element mounted on the second dielectric substrate; and a connecting member connecting the lead pins and one end of the first signal line; the first A bonding wire connects the other end of the first signal line and one end of the second signal line; a second bonding wire connects the other end of the second signal line and the semiconductor optical modulation element; and a lens cover is bonded to the upper surface of the metal tube seat, electrically connected to the metal tube seat, and hermetically seals the first and second metal blocks, the first and second dielectric substrates, the temperature control module, the first and second signal lines, the semiconductor optical modulation element, and the first and second bonding wires. The minimum distance between the first metal block and the inner wall of the lens cover is less than 0.37 mm, and the minimum distance between the second metal block and the inner wall of the lens cover is less than 1.36 mm.

[0008] In this disclosure, the minimum distance between the first metal block and the inner wall of the lens cover is less than 0.37 mm, and the minimum distance between the second metal block and the inner wall of the lens cover is less than 1.36 mm. This strengthens the grounding by bringing the first and second metal blocks closer to the grounded lens cover. Consequently, the number of resonant points is reduced, frequency response characteristics are improved, and a wide bandwidth is achieved. Therefore, a good optical waveform can be obtained without increasing the size of the lens cover. Attached Figure Description

[0009] Figure 1 This is a front-side perspective view of the optical semiconductor device according to Embodiment 1.

[0010] Figure 2 This is a perspective view of the back side of the optical semiconductor device according to Embodiment 1.

[0011] Figure 3 This is a top view showing the interior of the optical semiconductor device according to Embodiment 1.

[0012] Figure 4 This is a front side perspective view of a modified example 1 of the optical semiconductor device according to Embodiment 1.

[0013] Figure 5 This is a rear perspective view of a modified example 1 of the optical semiconductor device according to Embodiment 1.

[0014] Figure 6 This is a front side perspective view of a modified example 2 of the optical semiconductor device according to Embodiment 1.

[0015] Figure 7 This is a rear perspective view of a modified example 2 of the optical semiconductor device according to Embodiment 1.

[0016] Figure 8 This is a graph showing the simulation results of the frequency response characteristics under the condition that the minimum distance between the second metal block and the inner wall of the lens cover changes.

[0017] Figure 9 This is a graph showing the simulation results of the frequency response characteristics under the condition that the minimum distance between the first metal block and the inner wall of the lens cover is varied.

[0018] Figure 10 This is a graph showing the results of a three-dimensional electromagnetic field simulation comparing the frequency response characteristics of the optical semiconductor devices involved in the comparative example and embodiment 1.

[0019] Figure 11 This is a front-side perspective view of the optical semiconductor device according to Embodiment 2.

[0020] Figure 12 This is a perspective view of the back side of the optical semiconductor device according to Embodiment 2.

[0021] Figure 13 This is a top view showing the interior of the optical semiconductor device involved in Embodiment 2.

[0022] Figure 14 This is a graph showing the results of a three-dimensional electromagnetic field simulation comparing the frequency response characteristics of the optical semiconductor devices involved in the comparative example and embodiment 2.

[0023] Figure 15 This is a front-side perspective view of the optical semiconductor device according to Embodiment 3.

[0024] Figure 16 This is a perspective view of the back side of the optical semiconductor device according to Embodiment 3.

[0025] Figure 17 This is a top view showing the interior of the optical semiconductor device involved in Embodiment 3.

[0026] Figure 18 This is a graph showing the results of a three-dimensional electromagnetic field simulation comparing the frequency response characteristics of the optical semiconductor devices involved in the comparative example and embodiment 3.

[0027] Figure 19This is a cross-sectional view of the optical semiconductor device involved in Embodiment 4. Detailed Implementation

[0028] The optical semiconductor device according to the embodiments will be described with reference to the accompanying drawings. The same or corresponding components are sometimes labeled with the same reference numerals, and repeated descriptions are omitted.

[0029] Implementation Method 1

[0030] Figure 1 This is a front-side perspective view of the optical semiconductor device according to Embodiment 1. Figure 2 This is a perspective view of the back side of the optical semiconductor device according to Embodiment 1. Figure 3 This is a top view showing the interior of the optical semiconductor device according to Embodiment 1.

[0031] The metal socket 1 is a circular plate. Signal line leads 2 pass through the metal socket 1 and are fixed to it via glass. The metal socket 1 and leads 2 can be made of metals such as copper, iron, aluminum, or stainless steel, and can be plated with gold or nickel. Furthermore, in addition to signal line leads 2, multiple leads can be provided, such as power supply leads for the temperature control module and power supply leads for the laser diode section when installing the EAM-LD.

[0032] The first metal block 3 and the temperature control module 4 are mounted on the upper surface of the metal socket 1. The first metal block 3 is positioned near the lead pin 2. The second metal block 5 is mounted on top of the temperature control module 4. The first metal block 3 is made of a metal such as copper, iron, aluminum, or stainless steel. However, the first metal block 3 may also be a structure in which metal is coated onto an insulator such as ceramic or resin. The second metal block 5 is a block of metal material, for example, formed by plating Au or the like onto the surface of a material with high thermal conductivity, such as Cu. The temperature control module 4 has a Peltier element sandwiched between a heat dissipation surface and a cooling surface. The heat dissipation surface is joined to the metal socket 1, and the second metal block 5 is mounted on the cooling surface. The first and second dielectric substrates 6 and 7 are respectively mounted on the sides of the first and second metal blocks 3 and 5.

[0033] Furthermore, from an assembly point of view, the metal block is separated into a first metal block 3 and a second metal block 5. Additionally, this separation reduces the amount of heat flowing from the outside into the second dielectric substrate 7 and the second metal block 5 via the metal socket 1. Therefore, the power consumption of the temperature control module 4 can be reduced.

[0034] The first signal line 8 and the ground conductor 9 are formed on the first dielectric substrate 6. The first signal line 8 and the ground conductor 9 are configured to be spaced apart from each other to form a coplanar line. The ground conductor 9 is connected to the first metal block 3 through a through hole (not shown) formed on the first dielectric substrate 6.

[0035] The second signal line 10, the ground conductor 11, and the matching resistor 12 are formed on the second dielectric substrate 7. The second signal line 10 and the ground conductor 11 are arranged to be spaced apart from each other, thus forming a coplanar line. The ground conductor 11 is also formed on the side of the second dielectric substrate 7.

[0036] The semiconductor optical modulation element 13 is mounted on the second dielectric substrate 7. The semiconductor optical modulation element 13 may be, for example, a modulator-integrated laser (EAM-LD) that integrates an electro-absorption type optical modulator using an InGaAsP quantum well absorption layer and a distributed feedback laser diode into a single unit, or an MZ (Mach-Zehnder) semiconductor optical modulator. Heat generated in the semiconductor optical modulation element 13 is diffused via the second metal block 5 and the metal socket 1.

[0037] Connector 14 connects lead pin 2 to one end of the first signal line 8. Connector 14 can be solder, but it can also be a bonding wire. Bond wire 15 connects the other end of the first signal line 8 to one end of the second signal line 10. Bond wire 16 connects the other end of the second signal line 10 to the semiconductor optical modulator 13. Bond wire 17 connects the semiconductor optical modulator 13 to one end of the matching resistor 12. Bond wire 18 connects the other end of the matching resistor 12 to the second metal block 5.

[0038] The lens cover 19 is joined to the upper surface of the metal tube seat 1 and electrically connected to the metal tube seat 1, thereby hermetically sealing the first and second metal blocks 3 and 5, the first and second dielectric substrates 6 and 7, the temperature control module 4, the first and second signal lines 8 and 10, the semiconductor optical modulation element 13, the connecting component 14, and the bonding wires 15 to 18, etc. The lens cover 19 is made of metal such as copper, iron, aluminum, or stainless steel, and is conical or straight. However, the lens cover 19 can also be a structure in which metal is coated onto an insulator such as ceramic or resin.

[0039] The first metal block 3 has a width of a, a depth of b, and a height of c. The back surface of the first metal block 3 is a curved surface shape along the inner wall of the cylindrical lens cover 19. By making the width a or depth b of the first metal block 3 larger than before, the back surface of the first metal block 3 is brought closer to the inner wall of the lens cover 19. As a result, the minimum distance d1 between the first metal block 3 and the inner wall of the lens cover 19 is less than 0.37 mm, here it is 0.10 mm.

[0040] The second metal block 5 has a width of d, a depth of e, and a height of f. The cross-section of the second metal block 5 is L-shaped, with a portion of its side surface curving along the inner wall of the lens cover 19. By making the width d or depth e of the second metal block 5 larger than before, the side surface of the second metal block 5 is brought closer to the inner wall of the lens cover 19. As a result, the minimum distance d2 between the second metal block 5 and the inner wall of the lens cover 19 is less than 1.36 mm, here it is 0.10 mm.

[0041] Figure 4 This is a front side perspective view of a modified example 1 of the optical semiconductor device according to Embodiment 1. Figure 5 This is a rear perspective view showing a modified example 1 of the optical semiconductor device according to Embodiment 1. The lens cover 19 is cylindrical, but a portion of the inner wall of the lens cover 19 protrudes toward the first metal block 3. As a result, the two are close together, and the minimum distance d1 between the first metal block 3 and the inner wall of the lens cover 19 becomes less than 0.37 mm, and the minimum distance d2 between the second metal block 5 and the inner wall of the lens cover 19 becomes less than 1.36 mm.

[0042] Figure 6 This is a front side perspective view of a modified example 2 of the optical semiconductor device according to Embodiment 1. Figure 7 This is a rear perspective view showing a modified example 2 of the optical semiconductor device according to Embodiment 1. A portion of the inner wall of the lens cover 19 protrudes toward the first metal block 3 and the second metal block 5. As a result, the two are brought closer together, and the minimum distance d1 becomes less than 0.37 mm, and the minimum distance d2 becomes less than 1.36 mm.

[0043] Figure 8 This is a graph showing the simulation results of the frequency response characteristics under varying minimum distances between the second metal block 5 and the inner wall of the lens cover 19. The frequency response characteristics are represented by characteristic S21. The minimum distance d2 between the second metal block 5 and the inner wall of the lens cover 19 is set to 1.36 mm, 0.5 mm, and 0 mm. The distance between the first metal block 3 and the inner wall of the lens cover 19 is always set to 0.37 mm. It can be seen that when the minimum distance d2 becomes less than 1.36 mm, especially in the region up to 30 GHz, the reduction caused by resonance is reduced and thus improved.

[0044] Figure 9 This is a graph showing the simulation results of the frequency response characteristics under the condition that the minimum distance between the first metal block 3 and the inner wall of the lens cover 19 varies. The minimum distance d1 between the first metal block 3 and the inner wall of the lens cover 19 is set to 0.37 mm and 0 mm. The distance between the second metal block 5 and the inner wall of the lens cover 19 is always set to 1.36 mm. It can be seen that when the minimum distance d1 becomes less than 0.37 mm, the decrease caused by resonance is reduced and thus improved.

[0045] Figure 10This is a graph showing the results of a three-dimensional electromagnetic field simulation comparing the frequency response characteristics of the optical semiconductor device involved in the comparative example and Embodiment 1. In the comparative example, the minimum distance d2 is 1.36 mm and the minimum distance d1 is 0.37 mm. It can be seen that in Embodiment 1, compared with the comparative example, the resonant point is reduced and the decrease in frequency response characteristics is smaller.

[0046] As explained above, in this embodiment, the shapes of the first and second metal blocks 3 and 5 are modified from the comparative example, such that the minimum distance between the first metal block 3 and the inner wall of the lens cover 19 is less than 0.37 mm, and the minimum distance between the second metal block 5 and the inner wall of the lens cover 19 is less than 1.36 mm. As a result, the first and second metal blocks 3 and 5 move closer to the grounded lens cover 19, thus strengthening the grounding. Therefore, the number of resonant points is reduced, the frequency response characteristics are improved, and a wide bandwidth can be achieved. Therefore, a good optical waveform can be obtained without increasing the size of the lens cover 19.

[0047] Implementation Method 2

[0048] Figure 11 This is a front-side perspective view of the optical semiconductor device according to Embodiment 2. Figure 12 This is a perspective view of the back side of the optical semiconductor device according to Embodiment 2. Figure 13 This is a top view showing the interior of the optical semiconductor device involved in Embodiment 2.

[0049] In this embodiment, the minimum distance d1 between the first metal block 3 and the inner wall of the lens cover 19 is 0 mm, and the minimum distance d2 between the second metal block 5 and the inner wall of the lens cover 19 is 0.30 mm. That is, the first metal block 3 is in contact with the inner wall of the lens cover 19. It is a structure in which a portion of the inner wall of the lens cover 19 protrudes and contacts the rear surface of the first metal block 3. However, this is not limited to this; any structure in which the inner wall of the lens cover 19 contacts one or more of the side, rear, or top surfaces of the first metal block 3 is acceptable.

[0050] Alternatively, the first metal block 3 and the lens cover 19 can be electrically connected by bonding them together with solder or conductive resin. For example, a pre-applied solder or conductive resin can be applied to the side or rear surface of the first metal block 3, and then heated after the lens cover 19 is installed, thereby bonding the first metal block 3 to the lens cover 19.

[0051] Figure 14 This is a graph showing the results of a three-dimensional electromagnetic field simulation comparing the frequency response characteristics of the optical semiconductor device involved in the comparative example and embodiment 2. It can be seen that in embodiment 2, compared to the comparative example, the resonant point is reduced, and the decrease in frequency response characteristics is smaller.

[0052] As explained above, in this embodiment, the lens cover 19 is in contact with the first metal block 3, and the grounding is strengthened compared to Embodiment 1. Therefore, the number of resonant points is reduced, and the frequency response characteristics are improved, thereby enabling broadband operation. Thus, a good optical waveform can be obtained without increasing the size of the lens cover 19.

[0053] Implementation Method 3

[0054] Figure 15 This is a front-side perspective view of the optical semiconductor device according to Embodiment 3. Figure 16 This is a perspective view of the back side of the optical semiconductor device according to Embodiment 3. Figure 17 This is a top view showing the interior of the optical semiconductor device involved in Embodiment 3.

[0055] In this embodiment, the minimum distance d1 between the first metal block 3 and the inner wall of the lens cover 19 is 0 mm, and the minimum distance d2 between the second metal block 5 and the inner wall of the lens cover 19 is also 0 mm. That is, not only the first metal block 3, but also the second metal block 5 is in contact with the inner wall of the lens cover 19.

[0056] The lens cover 19 is constructed such that it protrudes as part of the inner wall of the lens cover 19 and contacts the side and rear surfaces of the first metal block 3 and the rear surface of the second metal block 5. It is not limited to this, as long as the inner wall of the lens cover 19 contacts any one or more of the side, rear, and top surfaces of the first metal block 3 and any one or more of the rear and top surfaces of the second metal block 5.

[0057] Alternatively, the first and second metal blocks 3 and 5 and the lens cover 19 can be bonded together using solder or conductive resin to achieve electrical connection. For example, pre-applied solder or conductive resin is applied to the side or rear surface of the first metal block 3 and the rear surface of the second metal block 5, and then heated after the lens cover 19 is installed to bond the first and second metal blocks 3 and 5 to the lens cover 19.

[0058] Figure 18 This is a graph showing the results of a three-dimensional electromagnetic field simulation comparing the frequency response characteristics of the optical semiconductor device involved in the comparative example and embodiment 3. It can be seen that in embodiment 3, compared to the comparative example, the resonant point is reduced, and the decrease in frequency response characteristics is smaller.

[0059] As explained above, in this embodiment, the lens cover 19 is in contact with the first and second metal blocks 3 and 5, and the grounding is strengthened compared to embodiment 2. Therefore, the number of resonant points is reduced, and the frequency response characteristics are improved, thereby enabling broadband operation. Thus, a good optical waveform can be obtained without increasing the size of the lens cover 19.

[0060] Implementation Method 4

[0061] Figure 19 This is a cross-sectional view showing the optical semiconductor device according to Embodiment 4. The lens of the lens cover 19 is a flat glass 20. Therefore, even if the positional relationship between the lens and the semiconductor optical modulation element 13 is offset, the optical characteristics such as focal length or coupling efficiency will not be affected, thus mitigating the construction deviation and installation accuracy of the lens cover 19. Other structures and effects are the same as in Embodiment 1.

[0062] Alternatively, the flat glass 20 can be applied to embodiments 2 and 3. In this case, at least one of the first and second metal blocks 3 and 5 is in contact with the lens cover 19, but the effect of optical axis offset can be ignored. In addition, in order to prevent reflected light or etalon effect, the thickness of the flat glass 20 can be tilted or angled to engage with the lens cover 19.

[0063] Explanation of reference numerals in the attached figures

[0064] 1...Metal socket; 2...Lead pin; 3...First metal block; 4...Temperature control module; 5...Second metal block; 6...First dielectric substrate; 7...Second dielectric substrate; 8...First signal line; 10...Second signal line; 13...Semiconductor optical modulation element; 14...Connecting component; 15...Connecting wire; 16...Connecting wire; 19...Lens cover; 20...Plate glass.

Claims

1. An optical semiconductor device, characterized in that, The optical semiconductor device includes: Metal tube socket; Lead wires pass through the metal socket; The first metal block is installed on the upper surface of the metal tube seat; A first dielectric substrate is mounted on the side of the first metal block; The first signal line is formed on the first dielectric substrate; A temperature control module is installed on the upper surface of the metal tube socket; The second metal block is installed on the temperature control module; A second dielectric substrate is mounted on the side of the second metal block; The second signal line is formed on the second dielectric substrate; A semiconductor optical modulation element is mounted on the second dielectric substrate; A connecting component connects the lead pin to one end of the first signal line; The first junction line connects the other end of the first signal line and one end of the second signal line; The second bonding line connects the other end of the second signal line to the semiconductor optical modulation element; as well as A lens cover is engaged with the upper surface of the metal tube base, electrically connected to the metal tube base, and hermetically seals the first metal block and the second metal block, the first dielectric substrate and the second dielectric substrate, the temperature control module, the first signal line and the second signal line, the semiconductor optical modulation element, the connecting component, and the first bonding line and the second bonding line. The minimum distance between the first metal block and the inner wall of the lens cover is less than 0.37 mm. The minimum distance between the second metal block and the inner wall of the lens cover is less than 1.36 mm.

2. The optical semiconductor device according to claim 1, characterized in that, A portion of the inner wall of the lens cover protrudes toward the first metal block.

3. The optical semiconductor device according to claim 1, characterized in that, A portion of the inner wall of the lens cover protrudes toward the first metal block and the second metal block.

4. The optical semiconductor device according to any one of claims 1 to 3, characterized in that, The first metal block is in contact with the inner wall of the lens cover.

5. The optical semiconductor device according to any one of claims 1 to 3, characterized in that, The first metal block and the second metal block are in contact with the inner wall of the lens cover.

6. The optical semiconductor device according to any one of claims 1 to 3, characterized in that, The lens of the lens cover is made of flat glass.

7. The optical semiconductor device according to claim 4, characterized in that, The lens of the lens cover is made of flat glass.

8. The optical semiconductor device according to claim 5, characterized in that, The lens of the lens cover is made of flat glass.

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