JPH07131106A - Semiconductor laser module - Google Patents

Abstract

PURPOSE:To provide a semiconductor laser module which reduces manufacturing cost and allows excellent cooling performance and heat responsiveness. CONSTITUTION:A metal member 34 is connected to the stem 12 of a semiconductor laser package 14 which can be also used for a compact disc, etc., and the cooling plane 26 of an electronic cooling element 22 is connected to the metal member 34. The heat dissipating plane 24 of the electronic cooling element 22 is fixed to the inner plane of a semiconductor laser module package 21. Heat from the semiconductor laser 11 is dissipated to the electronic cooling element 22 from fixture 36 through the stem 12. A holder which stores an optical system is fixed to the disc-shaped plane of the cap 13 of the semiconductor laser package 14, and beams projected from the semiconductor laser 11 are permitted to optically couple to optical fiber 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module used as a light source for optical communication, and more particularly to a semiconductor laser module for cooling a semiconductor laser using an electronic cooling element.

[0002]

2. Description of the Related Art A semiconductor laser module in which a temperature of a semiconductor laser is kept constant by using an electronic cooling element such as a Peltier effect element is stable with little variation in optical output or wavelength with respect to changes in environmental temperature. The characteristics can be obtained. Therefore, such a semiconductor laser module is
It is widely used as a light source for medium to high speed and medium to long distance optical communication devices. Especially 600 Mb / s
A semiconductor laser module used in a medium-speed / medium-distance optical transmission device of about (megabyte / second) or less is required to have low cost and excellent cooling characteristics in consideration of severe operating environment conditions.

Conventionally, for example, JP-A-60-17200.
No. 7, JP-A-2-299281, JP-A-2-
As can be seen from the technique disclosed in Japanese Patent No. 247093, although a semiconductor laser is cooled by using an electronic cooling element, these are incorporated in a semiconductor laser module in their own design modes to manufacture. It was
For this reason, there are few semiconductor laser modules that are commonly used as components, and there is a problem that the price of the product becomes relatively high. Therefore, for example, by using a semiconductor laser used for a compact disc (CD) in a semiconductor laser module, common parts can be achieved,
A device that reduces the cost has been proposed.

FIG. 3 shows in principle the longitudinal sectional structure of such a cooling type semiconductor laser module that has been conventionally proposed. The semiconductor laser 11 is mounted on the stem 12. The stem 12 has a window glass cap 1
3 is fixed so as to cover the semiconductor laser 11 and is hermetically sealed.
Are configured. The semiconductor laser package 14 is the same as that used for a compact disc, for example. A portion of the stem 12 of the semiconductor laser package 14 is fixed to a cylindrical holder 16 with a screw 15. Inside the cylindrical holder 16, an optical coupling lens 17 (not shown) and a fixture 18 for fixing the same are provided.
Etc. are built in. When fixing the portion of the stem 12, position adjustment is performed so that the emitted light of the semiconductor laser 11 is optically coupled to the optical fiber 19. Thus, the semiconductor laser module unit 20 is constructed.

This semiconductor laser module unit 20
Are housed in a semiconductor laser module package 21 having wiring lead terminals (not shown). The semiconductor laser module package 21 includes an electronic cooling element 2
2 are also housed. Heat dissipation surface 24 of electronic cooling element 22
Is fixed to the inner surface of the semiconductor laser module package 21 by the solder 25, and the other cooling surface 26
The holder portion of the semiconductor laser module unit 20 is fixed with solder 27. After the semiconductor laser module unit 20 and the electronic cooling element 22 are attached to the semiconductor laser module package 21 in this way, the cover 29 is fixed by seam welding,
Cooled semiconductor laser modules have been manufactured.

[0006]

As described above, in the semiconductor laser module shown in FIG. 3, the optical system unit including the semiconductor laser package 14 and the optical fiber 19 is housed in the relatively large cylindrical holder. Therefore, if the temperature of the semiconductor laser 11 is to be controlled by the electronic cooling element 22, the entire holder having a large heat capacity must be cooled. For this reason, there are problems that the cooling capacity and the thermal response characteristics are poor, and the power consumption of the device is large.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a semiconductor laser module which can be manufactured at a low cost and has excellent cooling capacity and thermal response characteristics.

[0008]

According to a first aspect of the present invention, (a) a semiconductor laser package including a semiconductor laser-mounted stem and a cylindrical cap fixed to the stem, and (b) joined to the stem. A metal member,
(C) An electronic cooling element having its metal surface bonded to its cooling surface, and (d) a cylindrical package. An optical fiber terminal is arranged at one end of the electronic package and the light emitted from the semiconductor laser is placed inside the package. An optical system package in which an optical system optically coupled to the optical fiber terminal is arranged, and the other end of the package is joined to the disc-shaped upper surface of the cap, and (e) these semiconductor laser packages,
A semiconductor laser module is provided with a semiconductor laser module package that accommodates a metal member, an electronic cooling element, and an optical system package, and a heat dissipation surface of the electronic cooling element is bonded to a predetermined portion of the inner surface thereof.

That is, according to the first aspect of the invention, the semiconductor laser package including the stem on which the semiconductor laser is mounted and the cylindrical cap fixed to the stem is mass-produced as a component that can be shared by other products. We are trying to reduce the manufacturing cost. Then, by joining a metal member to the stem of the semiconductor laser package and joining the metal member to the cooling surface of the electronic cooling element,
The semiconductor laser is efficiently cooled through the stem to provide a semiconductor laser module having excellent cooling capacity and thermal response characteristics.

According to a second aspect of the present invention, the semiconductor laser package is characterized in that the stem and the semiconductor laser are fixed by a metal fixture and are hermetically sealed by a cap. In the former case, cooling by the electronic cooling element is effectively performed via the stem and the metal fixture. In the latter case, since the semiconductor laser package is hermetically sealed, its reliability is high.

According to a third aspect of the invention, the optical system package is characterized in that the disc-shaped upper surface of the cap is used as a lapping surface, and the optical system is adjusted and then welded and fixed to the cap. Easy to adjust the system.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows in principle the vertical cross-sectional structure of a semiconductor laser module according to an embodiment of the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be appropriately omitted. The semiconductor laser 11 of this embodiment
Is also mounted on the stem 12. A cap 13 with a window glass is fixed to the stem 12 and hermetically sealed, and the whole of them constitutes a semiconductor laser package 14. This semiconductor laser package 14 shares the same parts as those used for a compact disc, for example. An end of a cylindrical holder 31 is fixed in close contact with the upper surface of the cap 13 (the surface facing the right side in the figure). The cylindrical holder 31 accommodates a lens (not shown). An optical fiber 19 is connected to the surface of the holder 31 opposite to the surface to which the semiconductor laser package 14 is fixed, and the laser light emitted from the semiconductor laser 11 is optically coupled to the optical fiber through the lens. Thus, the positional relationship between the cap 13 and the holder 31 is adjusted.

In the semiconductor laser module unit 32 composed of the above components, the metal member 34 is joined to the outer periphery of the stem 12. This metal member 34 is
It is housed together with the electronic cooling element 22 in a semiconductor laser module package 21 having a wiring lead terminal (not shown). The heat dissipation surface 24 of the electronic cooling element 22 is fixed to the inner surface of the semiconductor laser module package 21 with solder 25, and the other cooling surface 26 is fixed to the metal member 34 with solder 35. The semiconductor laser 11 is a metal fixture 36 having one end joined to the stem 12.
It is fixed on. After the semiconductor laser module unit 32 and the electronic cooling element 22 are attached to the semiconductor laser module package 21, the cover 29 is fixed by seam welding to manufacture a cooling type semiconductor laser module.

As described above, in the semiconductor laser module of this embodiment, a small-sized coaxial type semiconductor laser module unit 32 is constructed by closely fixing the cylindrical holder 31 in which the lens is arranged on the upper surface of the cap 13. Then
By soldering and joining to the electronic cooling element 22 via the metal member 34 joined to the stem 12, a cooling type semiconductor laser module having excellent cooling characteristics is configured. Such a semiconductor laser module can be realized together with the establishment of a manufacturing technology for a small-sized coaxial semiconductor laser module. Regarding this, for example, NEC Technical Report Vol. 45, No. 1, published in November, 1992
There is a description from page 3 to page 11 of No. 0.

FIG. 2 specifically shows the structure of the semiconductor laser module of this embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be appropriately omitted. A semiconductor laser 11 is provided on the stem 12 (see FIG. 1).
Has been implemented. A cylindrical cap 13 is fixed to the stem 12, and a semiconductor laser package 14
Is configured. On the upper surface of the cap 13, a cylindrical holder 37 is fixed in close contact with it. The cylindrical holder 37 contains a lens 39 for optically coupling with the optical fiber terminal 38. An optical fiber terminal 38 is connected via a flanged support 40 to the surface of the cylindrical holder 37 opposite to the surface to which the semiconductor laser package 14 is fixed (the surface on the left side in the figure). The fixing position of the holder 37 on the upper surface of the cap 13 is adjusted so that the light emitted from the semiconductor laser 11 (FIG. 1) is optically coupled to the optical fiber terminal 38 via the lens 39, and laser welding / fixing is performed. Then, the semiconductor laser module unit 41 is constructed.

The wiring lead terminals 42 are embedded in the bottom plate portion 21A of the semiconductor laser module package 21. The electronic cooling element 2 is provided on the inner surface of the bottom plate portion 21A.
The second heat radiation surface 24 is fixed by the solder 25.
A metal member 34 is fixed to the cooling surface 26, which is the other surface of the electronic cooling element 22, with solder 35. When fixing this, the stem 1 of the semiconductor laser package 14
The metal member 34 is previously fixed to 2 by a method such as YAG welding. Then, the lead terminals 44 for the semiconductor laser and the monitor photodiode (not shown) are wired corresponding to the respective lead terminals 42 for wiring. After that, the cover 2 is provided on the semiconductor laser module package 21.
When 9 is fixed by seam welding, the manufacturing of the cooled semiconductor laser module is completed.

As described above, in this embodiment, the small-sized coaxial type semiconductor laser module is used as the semiconductor laser package 1.
No. 4 is joined to the electronic cooling element 22 by soldering via the metal member 34 joined to the stem 12. Therefore,
Unlike the conventional semiconductor laser module shown in FIG. 3 in which the electronic cooling element 22 is attached to the semiconductor laser module unit 20, the heat capacity of the holder portion becomes small, and the semiconductor laser 11 in the semiconductor laser package 14 generates the heat capacity. Since the heat generated is directly transmitted from the metal fixture 36 for fixing the semiconductor laser 11 to the electronic cooling element 22 via the stem 12 and the metal member 34, a semiconductor laser module having excellent cooling characteristics can be configured.

Further, in this embodiment, when manufacturing an optical system unit, a manufacturing apparatus common to a general coaxial type semiconductor laser module can be used. For this reason,
It is possible to realize a low-cost cooled semiconductor laser module with excellent mass productivity.

[0020]

As described above, according to the first aspect of the invention, since the semiconductor laser module is configured by using the semiconductor laser package that can be used for other purposes such as a compact disc, a plurality of products can be manufactured. The manufacturing process can be standardized among them, and the manufacturing cost can be reduced. Also, since semiconductor laser packages can be mass-produced,
It can be manufactured at low cost and the cost of the semiconductor laser module itself can be reduced. Further, according to the present invention, since the semiconductor laser package is cooled via the metal member and the stem, it is possible to easily obtain a semiconductor laser module having excellent cooling ability and thermal response characteristics.

According to the second aspect of the invention, in the semiconductor laser package, the stem and the semiconductor laser are fixed by the metal fixture and the cap is hermetically sealed. Therefore, in the case of the former case. The cooling by the electronic cooling element is effectively performed via the stem and the metal fixture. In the latter case, since the semiconductor laser package is hermetically sealed, a highly reliable semiconductor laser module can be realized for a long period of time.

Further, in the optical system package according to the third aspect, the disc-shaped upper surface of the cap is used as a lapping surface, and the optical system is adjusted and then welded and fixed to the cap. Therefore, the optical system can be easily adjusted. There is an advantage that can be done.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a main part of a semiconductor laser module according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a semiconductor laser module of the present embodiment with a part thereof cut away.

FIG. 3 is a longitudinal sectional view of a conventionally proposed cooling type semiconductor laser module.

[Explanation of symbols]

 Reference Signs List 11 semiconductor laser 12 stem 13 cap 14 semiconductor laser package 19 optical fiber 20 semiconductor laser module unit 21 semiconductor laser module package 22 electronic cooling element 24 heat dissipation surface 25 (for electronic cooling element) 25, 27, 35 solder 26 (for electronic cooling element) Cooling surface 29 Cover 31 Holder 32 Semiconductor laser module unit 34 Metal member 36 Fixing tool 39 Lens

Claims (3)

[Claims] 1. A semiconductor laser package including a stem on which a semiconductor laser is mounted, a cylindrical cap fixed to the stem, a metal member bonded to the stem, and an electron having a cooling surface bonded to the metal member. A cooling element and a cylindrical package are provided. An optical fiber terminal is disposed at one end of the cooling element, and an optical system for optically coupling the light emitted from the semiconductor laser to the optical fiber terminal is disposed inside the package. An optical system package in which the other end of this package is bonded to the disc-shaped upper surface of the cap, and a semiconductor laser package, a metal member, an electronic cooling element, and an optical system package are housed and an electronic cooling element A semiconductor laser module comprising: a semiconductor laser module package having a heat dissipation surface bonded to the semiconductor laser module package. . 2. The semiconductor laser module according to claim 1, wherein the semiconductor laser package has the stem and the semiconductor laser fixed with a metal fixture and is hermetically sealed with the cap. 3. The semiconductor laser module according to claim 1, wherein the optical system package has the disk-shaped upper surface as a lapping surface, and is fixed to the cap by welding after adjusting the optical system.