Semiconductor laser device and semiconductor laser module

Abstract

A metal block (2) is formed on a main surface of a circular plate-shaped metal submount (1). The block (2) has a mounting surface (2a) and a heat dissipation surface (2b) on the opposite side of the mounting surface (2a). A semiconductor laser chip (6) is mounted on the mounting surface of the block (2). A cap (9) has a lens (10) that condenses a laser beam emitted from the semiconductor laser chip (6) and a lens barrel (11) that holds the lens (10) and is fixed to the metal submount (1) or the block (2). The heat dissipation surface of the block (2) is not covered by the lens barrel (11) and is flush with a side surface of the metal submount (1).

Description

Technical Field

[0001] This disclosure relates to a TO-CAN type semiconductor laser device and a semiconductor laser module. Background Technology

[0002] In a TO-CAN type semiconductor laser device, a semiconductor laser chip is mounted on a block formed on the main surface of a circular metal socket (see, for example, Patent Document 1). The heat generated during the operation of the semiconductor laser chip is dissipated through the block and the metal socket.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2007-027375

[0004] In the past, to achieve miniaturization, the semiconductor laser chip and its components were all housed within the mirror barrel. However, due to the limited space within the mirror barrel, it was difficult to ensure sufficient volume for the components to serve as heat dissipation paths. Furthermore, since the path for dissipating heat radially from the semiconductor laser chip is only from the component towards the metal socket, the amount of heat dissipation is limited. Therefore, existing semiconductor laser devices suffer from poor heat dissipation, leading to problems such as reduced light output, component failure, or degradation of semiconductor laser characteristics. Summary of the Invention

[0005] This disclosure is made to solve the aforementioned problems and aims to provide a semiconductor laser device and semiconductor laser module that can improve heat dissipation.

[0006] The disclosed semiconductor laser device is a TO-CAN type semiconductor laser device, characterized by comprising: a circular plate-shaped metal base; a metal block formed on the main surface of the metal base, having a mounting surface and a heat dissipation surface opposite to the mounting surface; a semiconductor laser chip mounted on the mounting surface of the block; and a cover having: a lens for focusing a laser beam emitted from the semiconductor laser chip, and a lens barrel for holding the lens and fixing it to the metal base or the block, wherein the heat dissipation surface of the block is not covered by the lens barrel and is on the same side as the side of the metal base.

[0007] In this disclosure, the heat dissipation surface of the block is not covered by the lens barrel and is on the same side as the metal socket. Therefore, the heat from the semiconductor laser chip is dissipated not only laterally from the block towards the metal socket but also longitudinally from the heat dissipation surface of the block towards the outside. Thus, heat dissipation is efficiently achieved, allowing for the radial propagation of heat from the semiconductor laser chip, thereby improving heat dissipation performance. Attached Figure Description

[0008] Figure 1 This is a side view of the semiconductor laser device according to Embodiment 1.

[0009] Figure 2This is a front view showing the interior of the semiconductor laser device according to Embodiment 1.

[0010] Figure 3 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 1.

[0011] Figure 4 This is a side view of a comparative example semiconductor laser device.

[0012] Figure 5 This is a front view showing the interior of a comparative example semiconductor laser device.

[0013] Figure 6 This is a side view of the semiconductor laser device according to Embodiment 2.

[0014] Figure 7 This is a side view showing the semiconductor laser device of Embodiment 3.

[0015] Figure 8 This is a front view showing the interior of the semiconductor laser device according to Embodiment 3.

[0016] Figure 9 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 3.

[0017] Figure 10 This is a side view of the semiconductor laser device according to Embodiment 4.

[0018] Figure 11 This is a front view showing the interior of the semiconductor laser device according to Embodiment 4.

[0019] Figure 12 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 4.

[0020] Figure 13 This is a side view of the semiconductor laser device according to Embodiment 5.

[0021] Figure 14 This is a top view showing the semiconductor laser device of Embodiment 5.

[0022] Figure 15 This is a front view showing the interior of the semiconductor laser device according to Embodiment 5.

[0023] Figure 16 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 5.

[0024] Figure 17 This is a side view of the semiconductor laser device according to Embodiment 6.

[0025] Figure 18This is a front view showing the interior of the semiconductor laser device according to Embodiment 6.

[0026] Figure 19 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 6.

[0027] Figure 20 This is a cross-sectional view showing the semiconductor laser module of Embodiment 7. Detailed Implementation

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

[0029] Implementation Method 1

[0030] Figure 1 This is a side view of the semiconductor laser device according to Embodiment 1. Figure 2 This is a front view showing the interior of the semiconductor laser device according to Embodiment 1. Figure 3 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 1. The semiconductor laser device in this embodiment is a TO-CAN type semiconductor laser device.

[0031] A metal block 2 is formed on the main surface 1a of a circular metal tube seat 1. The metal tube seat 1 and the block 2 are made of the same material and are integrally formed. The block 2 has a flat mounting surface 2a and a heat dissipation surface 2b opposite to the mounting surface 2a. The mounting surface 2a is perpendicular to the main surface 1a of the metal tube seat 1. The heat dissipation surface 2b is a curved surface at the lower end of the block 2 and is the same surface as the side surface of the metal tube seat 1. When viewed from a direction perpendicular to the main surface 1a of the metal tube seat 1, the block 2 is semi-circular.

[0032] A power-carrying lead 3 passes through the through hole 1b of the metal tube socket 1. A sealing glass 4 fills the through hole 1b and insulates the lead 3 from the metal tube socket 1. The lead 3 is positioned on the upper side of the metal tube socket 1 in a manner that does not interfere with the block 2 located on the lower side of the metal tube socket 1.

[0033] Sub-substrate 5 is chip-bonded to the vicinity of the center of mounting surface 2a of block 2. Semiconductor laser chip 6 is chip-bonded to the metallized portion of sub-substrate 5. Photodiode 7 is mounted to the main surface 1a of metal socket 1 via sub-substrate 8 and monitors the light extracted from the rear end surface of semiconductor laser chip 6. Leads 3 are bonded to the surface electrode leads of semiconductor laser chip 6. Other leads 3 are bonded to the leads of the metallized portion of sub-substrate 5. This forms a current injection path.

[0034] The cover 9 has a lens 10 that focuses the laser beam emitted from the semiconductor laser chip 6, and a lens barrel 11 that holds the lens 10. The lens barrel 11 is fixed to the main surface 1a of the metal base 1, the mounting surface 2a of the block 2, and the front end surface of the block 2 by projection welding in a manner that covers the semiconductor laser chip 6, etc. (hermetically sealed). At this point, high-precision positioning is required to effectively couple the laser beam emitted from the semiconductor laser chip 6 with the lens 10. These technologies are among the most fundamental technologies in optical communication technology.

[0035] Specifically, first, the cover 9 is positioned along the Y direction so that the center line of the lens 10 coincides with that of the semiconductor laser chip 6. Next, the cover 9 is lowered in the -X direction until it contacts the mounting surface 2a of the block 2. Then, the cover 9 is slid in the -Z direction and welded to the metal tube base 1 and the block 2. According to this method, the positioning of the block 2 is mainly achieved through position adjustment in the Y direction, thus eliminating the need for multi-dimensional or higher axis adjustments as in the past.

[0036] A cutout 11a is formed on the side of the lens barrel 11 in a manner that matches the shape of the heat dissipation surface 2b of the block 2. The cutout 11a of the lens barrel 11 is fitted into the block 2. The heat dissipation surface 2b of the block 2 protrudes from the cutout 11a to the outside of the lens barrel 11 and is not covered by the lens barrel 11.

[0037] Alternatively, the lens barrel 11 can be fixed by bonding or other welding methods, and the fixing location is not limited to the examples mentioned above, as long as it does not obstruct heat dissipation from the heat dissipation surface of block 2. Whether or not an airtight seal is used depends on the application or environment. The mounted chip is not limited to the semiconductor laser chip 6; any heat-generating chip can enjoy the advantages unique to this structure. Alternatively, the semiconductor laser chip 6 can be mounted on block 2 without using the sub-substrate 5.

[0038] Next, the effects of this embodiment will be compared and explained with those of the comparative examples. Figure 4 This is a side view of a comparative example of a semiconductor laser device. Figure 5 This is an internal front view of the comparative example semiconductor laser device. In the comparative example, the semiconductor laser chip 6, sub-substrate, and block 2 are all housed within the mirror barrel 11. Due to the limited space within the mirror barrel 11, the volume of block 2, which serves as a heat dissipation path, cannot be adequately ensured. Furthermore, since the only path for dissipating heat from the semiconductor laser chip 6 is from block 2 towards the metal socket 1, the heat dissipation is limited. Therefore, the comparative example semiconductor laser device has poor heat dissipation.

[0039] In contrast, in this embodiment, the heat dissipation surface of block 2 is not covered by the lens barrel 11 and is on the same side as the metal tube seat 1. By making the side of the metal tube seat 1 and the heat dissipation surface of block 2, which are on the same side, contact an external heat sink (not shown), heat can be dissipated from both the metal tube seat 1 and block 2. As a result, the heat of the semiconductor laser chip 6 is dissipated not only laterally from block 2 to the metal tube seat 1, but also longitudinally from the heat dissipation surface 2b of block 2 to the outside. Therefore, heat dissipation can be efficiently achieved by dissipating the heat that propagates radially from the semiconductor laser chip 6, thus improving heat dissipation performance.

[0040] Furthermore, the heat dissipation surface 2b of block 2 extends in the -X direction to the lower end of block 2 until it becomes flush with the side surface of the metal tube seat 1. Furthermore, block 2 extends along the laser beam emission direction, i.e., the Z direction, within a range where the front end of block 2 does not interfere with the cover 9. This increases the volume of block 2, thereby widening the heat diffusion path of the semiconductor laser chip 6 and improving heat dissipation. By improving heat dissipation, the characteristics of the semiconductor laser during high-temperature operation are particularly improved.

[0041] Since the laser beam emitted from the semiconductor laser chip 6 is orthogonal to the lens 10, the shape of the lens barrel 11 of the lens 10 remains simple. Furthermore, there is no interference above the mounting surface 2a of the block 2, thus facilitating the mounting of the semiconductor laser chip 6 and the sub-substrate 5.

[0042] In the comparative example, positioning the lens barrel 11 to align the center of the cap 9 with the center of the metal tube base 1 requires time for optical axis adjustment. However, in this embodiment, by fitting the cutout 11a of the lens barrel 11 into the block 2, optical axis adjustment can be performed in a short time. By ensuring the accuracy of the shape of the cutout 11a of the fitted lens barrel 11 and the block 2, positioning deviations can be suppressed. Furthermore, by removing only a portion of the cylindrical lens barrel 11 to expose the block 2, the shape of the lens barrel 11 is simple.

[0043] When using a spherical lens or similar lens with high focusing power as lens 10, the height of the lens barrel 11 needs to be increased to ensure the distance between the semiconductor laser chip 6 and lens 10. In this embodiment, since the lens 10 with cover 9 is arranged along the laser beam emission direction, it is not limited by the type of lens 10 or the height of lens barrel 11. Therefore, even if the height of lens barrel 11 is increased, the laser beam can still pass through lens 10. This provides a high degree of freedom in optical design and high coupling efficiency with lens 10.

[0044] Furthermore, when a cover is formed by combining a square lens barrel with a circular spherical lens, stress concentrates at the four corners of the lens barrel window, raising concerns about the cover's performance. However, since the cover 9 of this embodiment uses a cylindrical lens barrel 11, stress concentration can be prevented and it isotropic, thereby achieving stable cover performance.

[0045] Implementation Method 2

[0046] Figure 6 This is a side view of the semiconductor laser device according to Embodiment 2. Block 2 extends along the z-direction of the laser beam 12 emitted from the semiconductor laser chip 6. The length of this block 2 in the z-direction is limited so that the front end of the block 2 between the semiconductor laser chip 6 and the lens 10 does not interfere with the laser beam 12. As a result, the optical coupling of the laser beam 12 to the lens 10 can be improved. Other structures and effects are the same as in Embodiment 1.

[0047] Furthermore, the laser beam 12 is emitted elliptically from the semiconductor laser chip 6, and its output decreases from the center to the outer periphery. Therefore, even if a portion of the laser beam 12 interferes with the front end of the block 2 without coupling with the lens 10, there is no problem as long as the required light output is met.

[0048] Implementation Method 3

[0049] Figure 7 This is a side view showing the semiconductor laser device of Embodiment 3. Figure 8 This is a front view showing the interior of the semiconductor laser device according to Embodiment 3. Figure 9 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 3.

[0050] A recess 2c is partially formed at the center of the front end of block 2 along the path of the laser beam emitted from semiconductor laser chip 6. Since the laser beam passes through the recess 2c, the front end of block 2 does not interfere with the laser beam between semiconductor laser chip 6 and lens 10. This improves the optical coupling of the laser beam to lens 10. Other structures and effects are the same as in Embodiment 1.

[0051] Implementation Method 4

[0052] Figure 10 This is a side view of the semiconductor laser device according to Embodiment 4. Figure 11 This is a front view showing the interior of the semiconductor laser device according to Embodiment 4. Figure 12 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 4.

[0053] A semi-circular groove 2d is formed at the front end of the mounting surface 2a of block 2, matching the curvature of the circular plate-shaped lens barrel 11. The outer periphery of the lens barrel 11, which is machined to be shorter than in embodiment 1, fits into the groove 2d. Thus, the lens barrel 11 is fixed to block 2. In addition, the fixing method at this time can be, for example, welding, bonding, etc., but is not limited to these.

[0054] Block 2 also serves to extend along the Z-direction and fix the lens barrel 11. In this way, the area of ​​the mounting surface 2a of block 2 can be increased, improving the mounting and assembly of the semiconductor laser chip 6 and the sub-substrate 5. Furthermore, the fixing operation of the lens barrel 11 can be made more efficient. Positioning deviations are suppressed through the interlocking structure, and light coupling to the lens 10 is improved. In addition, by using a shorter lens barrel 11, it is also expected to reduce component costs, simplify the manufacturing process, and lower costs. Other structures and effects are the same as in Embodiment 1.

[0055] Furthermore, the semiconductor laser chip 6 and the sub-substrate 5 are mounted near the center of the mounting surface 2a of block 2 and are not covered by the lens barrel 11 (not hermetically sealed). Depending on the usage environment, such as the installation in an indoor facility, the lens barrel 11 is not required to protect the semiconductor laser chip 6. In addition, during TOSA or modular installation, the semiconductor laser device may be covered by hard objects such as brackets, so there are also specifications where the lens barrel 11 does not protect the semiconductor laser chip.

[0056] Implementation Method 5

[0057] Figure 13 This is a side view of the semiconductor laser device according to Embodiment 5. Figure 14 This is a top view showing the semiconductor laser device of Embodiment 5. Figure 15 This is a front view showing the interior of the semiconductor laser device according to Embodiment 5. Figure 16 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 5.

[0058] Block 2 has a two-layer structure, comprising a lower block 21 and an upper block 22 formed on the upper surface of the lower block 21 and narrower than the lower block 21. The lower surface of the lower block 21 is a heat dissipation surface 2b. The semiconductor laser chip 6 and the sub-substrate 5 are fixed near the center of the mounting surface 2a of the upper block 22. By making module 2 a two-layer structure, heat diffused radially from the semiconductor laser chip 6 can be dissipated efficiently.

[0059] The lens barrel 11 is fixed to the main surface 1a of the metal tube base 1 and the upper surface of the lower block 21 by projection welding, thus achieving a hermetic seal. Because the block 2 adopts a two-layer structure, it has excellent assemblability and expandability.

[0060] The lower block 21 extends along the Z-direction to a position near the direct below of the lens 10. The width of the upper block 22 in the X-direction is increased within the range accommodated in the lens barrel 11, while taking into account ease of mounting the sub-substrate 5. The upper block 22 extends along the Z-direction to a position where it does not interfere with the lens barrel 11 and the lens 10. However, it is preferable that the upper block 22 has its length in the Z-direction limited as in Embodiment 2, or that it has a recess 2c formed as in Embodiment 3, so that the front end of the upper block 22 does not interfere with the laser beam.

[0061] Implementation Method 6

[0062] Figure 17 This is a side view of the semiconductor laser device according to Embodiment 6. Figure 18 This is a front view showing the interior of the semiconductor laser device according to Embodiment 6. Figure 19 This is a perspective view showing the socket, block, and cover of the semiconductor laser device according to Embodiment 6.

[0063] The outer diameter of block 2 is the same as that of metal tube seat 1, and the side surface of block 2, including heat dissipation surface 2b, is the same as the side surface of metal tube seat 1. Block 2 has an inclined surface 2e that is inclined at an angle θ relative to the main surface 1a of metal tube seat 1. A mounting surface 2a perpendicular to the main surface 1a of metal tube seat 1 is formed at the center of inclined surface 2e. Semiconductor laser chip 6 and sub-substrate 5 are mounted on mounting surface 2a. A recess 2f is formed at the outer periphery of inclined surface 2e.

[0064] The end of the cylindrical lens barrel 11 is cut off at an angle θ corresponding to the inclined surface 2e of the block 2. That is, the end of the lens barrel 11 is also inclined at an angle θ relative to the bottom surface of the lens barrel 11 to which the lens 10 is fixed. The end of the lens barrel 11 fits into the recess 2f of the inclined surface 2e of the block 2. As a result, positioning of the lens barrel 11 becomes easier during assembly. In addition, by making the bottom surface of the recess 2f slightly larger than the outer shape of the lens barrel 11, small positional adjustments of the lens barrel 11 relative to the X and Y directions can be made during assembly.

[0065] Implementation Method 7

[0066] Figure 20This is a cross-sectional view showing the semiconductor laser module of Embodiment 7. The semiconductor laser device 100 in this figure is the semiconductor laser device of Embodiment 1, but it could also be any of Embodiments 2 to 6. A cylindrical support 101 holds the semiconductor laser device 100 and optically couples the semiconductor laser device 100 to the fiber optic socket 102. An opening 101a is formed on a portion of the curved surface at the lower end of the support 101, matching the shape of the block 2 of the semiconductor laser device 100. The heat dissipation surface 2b of the block 2 is not covered by the support 101 and is exposed through the opening 101a. This allows for efficient heat dissipation from the semiconductor laser chip 6. Furthermore, since the shape of the semiconductor laser module formed by combining the semiconductor laser device 100 and the support 101 is basically the same as conventional modules, optical axis alignment is easily achieved when installing the optical transceiver.

[0067] Explanation of reference numerals in the attached figures

[0068] 1… Metal tube base, 1a… Main surface, 2… Block, 2a… Mounting surface, 2b… Heat dissipation surface, 2c… Recess, 2d… Groove, 2e… Inclined surface, 2f… Recess, 6… Semiconductor laser chip, 9… Cover, 10… Lens, 11… Lens barrel, 11a… Cutout, 21… Lower layer block, 22… Upper layer block, 100… Semiconductor laser device, 101… Support, 101a… Opening.

Claims

1. A semiconductor laser device, specifically a TO-CAN type semiconductor laser device, characterized in that, have: A circular, plate-shaped metal tube seat; A metal block formed on the main surface of the metal tube seat, having a mounting surface and a heat dissipation surface opposite to the mounting surface; A semiconductor laser chip, which is mounted on the mounting surface of the block; as well as The cover comprises: a lens for focusing a laser beam emitted from the semiconductor laser chip, and a lens barrel for holding the lens and fixing it to the metal tube base or the block. The heat dissipation surface of the block is not covered by the mirror tube and is on the same side as the side of the metal tube seat.

2. The semiconductor laser device according to claim 1, characterized in that, The lens barrel has cutouts formed in a manner that matches the shape of the heat dissipation surface of the block. The cut in the lens barrel fits into the block. The heat dissipation surface of the block is exposed from the cut.

3. The semiconductor laser device according to claim 1 or 2, characterized in that, Between the semiconductor laser chip and the lens, the front end of the block does not interfere with the laser beam.

4. The semiconductor laser device according to claim 3, characterized in that, A recess is formed at the front end of the block along the path of the laser beam.

5. The semiconductor laser device according to claim 1, characterized in that, A semi-circular groove is formed on the mounting surface of the block. The outer periphery of the circular lens tube fits into the groove.

6. The semiconductor laser device according to any one of claims 1 to 4, characterized in that, The block has: a lower block, and an upper block formed on the upper surface of the lower block and narrower than the lower block. The lens barrel is fixed to the main surface of the metal tube base and the upper surface of the lower block.

7. The semiconductor laser device according to claim 1, characterized in that, The block has an inclined surface that is tilted relative to the main surface of the metal tube seat. A recess is formed on the outer periphery of the inclined surface. The cylindrical end of the lens tube is cut off at an angle corresponding to the inclined surface. The end of the lens barrel is fitted into the recess of the inclined surface.

8. A semiconductor laser module, characterized in that, have: The semiconductor laser device according to any one of claims 1 to 7; and A support structure holds the semiconductor laser device and optically couples it to an optical fiber. An opening is formed in a portion of the support. The heat dissipation surface of the block is exposed from the opening.

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