JP2001085780A - Semiconductor laser module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a semiconductor laser module, where the overall height occupied by parts in a package is lowered by the arrangement of the parts. SOLUTION: An area near one side of an optical fiber 22 is fixed to one side sidewall of a semiconductor laser module 20. An electronic cooling element 23 is fixed to the inner bottom surface of a module package 21. An upper-stage part 24U of a substrate 24 made of a metal plate, composed in two stages by providing a step (h), is fixed onto the upper surface of the electronic cooling element 23. A semiconductor laser 25 is fixed to the end part of the upper-stage part 24U. A lens 26 is fixed to a lower-stage part 24D of the substrate, thus reducing the overall height occupied by each parts by the amount of the step (h).

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 for, for example, optical communication and optical information processing. More specifically, the present invention relates to an optical fiber for emitting a light beam emitted from a semiconductor laser whose temperature is adjusted by a cooling element. The present invention relates to a semiconductor laser module coupled to

[0002]

2. Description of the Related Art Semiconductor laser modules are widely used as signal light sources used in optical fiber transmission devices and the like. Transmission devices using optical fibers have been miniaturized, and high integration of circuit boards has been demanded. At the same time, various components incorporated in the circuit board have been reduced in size and height. In relation to such components, the semiconductor laser module is also required to be particularly thin.

FIG. 2 shows the structure of a conventional semiconductor laser module. Semiconductor laser module 10
One end of an optical fiber 12 for transmitting an optical signal is accommodated in one side wall of the module package 11.
An electronic cooling element 13 is disposed on the inner bottom surface of the module package 11. A semiconductor laser 15 and a light beam emitted from the semiconductor laser 15 are optically coupled to the optical fiber 12 via a substrate 14. A lens 16 is provided.

[0004] In the semiconductor laser module 10, the following contrivance has been made to reduce the height of the module package 11 as much as possible. The electronic cooling element 13 is minimized in thickness in order to exhibit a required cooling capacity. The substrate 14 disposed thereon is provided with a lens 16
Is processed so that the portion on which is mounted is as thin as possible. Since the height of the portion on which the semiconductor laser 15 is mounted is set so that the optical axis of the lens 16 coincides with the laser beam, this portion needs a certain thickness (height). The smaller the diameter of the lens 16 is, the lower the height of the module package 11 can be. However, in practice, it is necessary to secure a predetermined aperture angle (NA). I have.

[0005]

As described above, in the structure of the conventional semiconductor laser module, the thickness of the substrate 14 where the lens 16 is mounted is reduced in order to minimize the overall height of the internal components. It is as thin as possible. However, the electronic cooling element 13 and the substrate 1 placed thereon
4. The height occupied by the various components (chip-on-carrier) such as the semiconductor laser 15 as a whole, even if the thickness of the substrate 14 is set to the processing limit,
It was logically impossible to make the height lower than the sum of the height of the lens 16 and the diameter of the lens 16.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor laser module which can reduce the overall height occupied by these components in a package by devising the arrangement of the components.

Another object of the present invention is to provide a semiconductor laser module capable of reducing the height of the whole components in a package as compared with the value obtained by adding the diameter of the lens to the height of the cooling element.

[0008]

According to the first aspect of the present invention, there are provided (a) a module package, and (b) a thermally conductive substrate having a planar upper and lower portion with a step portion as a boundary. (C) a temperature control element for temperature control, the lower surface of which is fixed to the inner bottom surface of the module package and the upper surface of which is fixed to the lower surface of the upper step of the substrate; (d) a semiconductor laser disposed on the substrate; The semiconductor laser module includes an optical fiber and a lens fixed to the lower portion of the substrate and optically coupling the semiconductor laser and the optical fiber.

That is, according to the first aspect of the present invention, the substrate disposed on the temperature adjusting element such as a Peltier element for adjusting the temperature has a structure including an upper part, a lower part, and a step connecting these parts. The lower surface of the upper portion is fixed to the upper surface of the temperature control element. As a result, the lower part is arranged at a position lower than the upper part by the step part. If the semiconductor laser is arranged in the upper part and the lens is fixed to the lower part, the distance from the bottom of the module package to the upper end of the lens is increased. The height can be made lower than before.

According to a second aspect of the present invention, the lower portion of the substrate is arranged closer to the inner bottom surface of the module package than the upper portion by the step portion. If the step is made relatively large, the position of the lower part of the substrate can be made lower. As a result, the height can be reliably reduced as compared with the conventional semiconductor laser module. Of course, the upper surface of the lower part of the substrate does not necessarily need to be lower than the upper surface of the temperature adjustment element.

According to a third aspect of the present invention, the lower surface of the lower portion of the substrate is arranged in a non-contact state at a predetermined distance from the inner bottom surface of the module package. Accordingly, heat is not directly conducted between the substrate and the module package, so that heat energy can be effectively used, and the size of the temperature adjustment element can be reduced.

According to the invention described in claim 4, (a) a module package having a predetermined shape, (b) a semiconductor laser for emitting laser light, (c) an optical fiber fixed to the module package, and (d) A) a lens for optically coupling the semiconductor laser and the optical fiber, and (e) a member for mounting the semiconductor laser, the heights of which are different from each other with respect to the bottom surface of the module package at the bent portion. A substrate having first and second surfaces, and a temperature adjusting element for temperature adjustment fixed to the first surface of the substrate, wherein the semiconductor laser and the lens are located in an area other than immediately above the temperature adjusting element. It is characterized by being arranged.

According to the fifth aspect of the present invention, the semiconductor laser module comprises: (a) a module package having a predetermined shape; (b) a semiconductor laser for emitting laser light;
(C) a temperature control element for temperature control; and (d) a first and a second surface with the bent portion as a boundary, the temperature control element being fixed to the first surface, and a module package. Is characterized in that the first surface is located at a position farther from the second surface when the bottom surface is used as a reference.

According to the present invention, (a) a module package having a predetermined shape, (b) a semiconductor laser for emitting laser light, (c) an optical fiber fixed to the module package, and (d) A) a lens that optically couples the semiconductor laser and the optical fiber; and (e) a member for mounting the semiconductor laser, which has an upper portion and a lower portion with the bent portion as a boundary. The semiconductor laser module includes a substrate at a position higher than the lower surface of the lens, and a temperature adjusting element for temperature adjustment fixed to the lower surface of the upper stage.

According to a seventh aspect of the present invention, in the semiconductor laser module according to the fourth to sixth aspects, the first and second surfaces are parallel to the bottom surface.

According to an eighth aspect of the present invention, in the semiconductor laser module according to the fourth to sixth aspects, the first and second semiconductor laser modules are provided.
Are parallel to each other.

According to a ninth aspect of the present invention, in the semiconductor laser module of the fourth to sixth aspects, the third surface constituting the bent portion and the first and second surfaces connected thereto are perpendicular to each other. The first to third surfaces are integrated to form a substrate.

According to a tenth aspect of the present invention, in the semiconductor laser module according to the first aspect, the temperature adjustment element is an electronic cooling element for electronically cooling the semiconductor laser. And

According to a tenth aspect of the present invention, the temperature adjusting element is an electronic cooling element for electronically cooling the semiconductor laser. Needless to say, not only the cooling element but also a heating element can be freely arranged as needed or alone.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows the structure of a semiconductor laser module according to an embodiment of the present invention. The semiconductor laser module 20 of this embodiment uses a slightly elongated module package 21. On one side wall, the vicinity of one end of the optical fiber 12 for transmitting an optical signal is YA.
G is fixed. An electronic cooling element 23 made of a Peltier element is fixed to the inner bottom surface of the module package 21 by soldering. On the upper surface of the electronic cooling element 23, an upper portion 24U of a substrate 24 made of a metal plate having two steps with a predetermined step h is fixed by soldering. A semiconductor laser 25 is fixed to the end of the upper portion 24U near the optical fiber 22 by soldering.
The fixed position of the optical fiber 22 is set in advance so that the optical axis thereof coincides with the height of the emission portion of the semiconductor laser 25. On the upper surface of the lower portion (crank portion) 24D of the substrate,
The lens 26 is fixed by YAG. Step h of substrate 24
Is set to a value such that the optical axis of the lens 26 matches the optical axis of the optical fiber 22. The lower surface of the lower portion 24D of the substrate is not in contact with the inner bottom surface of the module package 21.

In the semiconductor laser module 20 having such a configuration, the semiconductor laser 25 and the optical fiber 22 are optically coupled by the lens 26. The semiconductor laser 25 is dissipated by the thermoelectric cooler 23 via the substrate 24, and is kept in a desired temperature range.

Moreover, in the semiconductor laser module 20 of this embodiment, the step h is provided on the substrate 24, and the height of the upper surface of the lower portion 24D can be made lower than the height of the upper surface of the electronic cooling element 23. Therefore, the height of the entire components in the module package 20 is
Of the electronic cooling element 23 and the thickness of the substrate 24 are simply added to the height of the electronic cooling element 23, and of course, the overall height may be reduced depending on the height of the electronic cooling element 23 and the set value of the step h. In addition, it is possible to greatly reduce the value obtained by simply adding the height of the electronic cooling element 23 and the aperture of the lens 26.
Therefore, the degree of freedom in selecting various components such as the electronic cooling element 23 is increased, and a margin can be given in terms of performance and reliability of the components. Of course, the height of the semiconductor laser module can be significantly improved by setting the heights of the various components to the limit values.

In the embodiment, one semiconductor laser is arranged in the semiconductor laser module.
The present invention can be applied to a semiconductor laser module in which two or more semiconductor lasers are arranged as disclosed in Japanese Patent Application No. -281442.

In the embodiment, an example of the lower portion of the substrate is shown. However, the shape, the position, and the height of various components (chip-on-carriers) arranged on the temperature adjusting element are determined according to the shape and size of the components. It is possible to make various modifications.

[0026]

As described above, according to the first aspect of the present invention, the substrate disposed on the temperature adjusting element has a structure including an upper part, a lower part, and a step connecting these parts, The lower surface of the upper portion is fixed to the upper surface of the temperature control element. Thereby, the lower part will be arranged at a position lower than the upper part by the amount of the step,
If the semiconductor laser is arranged on the upper part and the lens is fixed on the lower part, the height from the bottom surface of the module package to the upper end of the lens can be reduced. Therefore, it is possible to reduce the height of the semiconductor laser module while giving some margin to the performance and size of each component, thereby contributing to economy and downsizing of the transmission device. In addition, miniaturization of individual components can further promote miniaturization of the semiconductor laser module.

According to the second aspect of the present invention, the position of the lower part of the substrate can be made lower by making the step relatively large, and the thickness of the substrate can be reduced as in the prior art. It is not necessary to make the fixed portion of the semiconductor laser different from the fixed portion of the semiconductor laser. Therefore, there is an advantage that the processing of the substrate is simply performed by, for example, simply bending a flat plate, and is facilitated.

According to the third aspect of the present invention, the lower surface of the lower portion of the substrate is in a non-contact state at a predetermined distance from the inner bottom surface of the module package. For this reason,
Since heat is not directly conducted between the substrate and the module package, heat energy can be effectively used, and the size of the temperature adjustment element can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a structure of a semiconductor laser module according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a structure of a conventional semiconductor laser module.

[Explanation of symbols]

 Reference Signs List 20 semiconductor laser module 21 module package 22 optical fiber 23 thermoelectric cooler 24 substrate 24U upper part 24D lower part 25 semiconductor laser 26 lens h step

Claims (10)

[Claims] 1. A module package, a thermally conductive substrate having an upper portion and a lower portion which are planar with a step portion as a boundary, a lower surface fixed to an inner bottom surface of the module package, and an upper surface of the module package A temperature adjustment element for temperature adjustment fixed to the lower surface of the upper portion, a semiconductor laser disposed on the substrate, an optical fiber, and an optical fiber fixed to the lower portion of the substrate and optically connecting the semiconductor laser and the optical fiber. And a lens coupled to the semiconductor laser module. 2. The module according to claim 1, wherein a lower portion of the substrate is disposed closer to an inner bottom surface of the module package than the upper portion by the step portion.
The semiconductor laser module according to the above. 3. The semiconductor laser module according to claim 1, wherein a lower surface of the lower portion of the substrate is disposed in a non-contact state with a predetermined distance from an inner bottom surface of the module package. 4. A module package having a predetermined shape, a semiconductor laser for emitting laser light, an optical fiber fixed to the module package, a lens for optically coupling the semiconductor laser and the optical fiber, A substrate for mounting the semiconductor laser, the substrate having a first surface and a second surface having different heights with respect to a bottom surface of the module package at a bent portion thereof; A semiconductor laser module, comprising: a temperature adjustment element for temperature adjustment fixed to a surface, wherein the semiconductor laser and the lens are arranged in a region other than immediately above the temperature adjustment element. 5. A module package having a predetermined shape, a semiconductor laser for emitting laser light, a temperature control element for temperature control, and first and second surfaces bordering the bent portion thereof, A semiconductor laser module, wherein a temperature adjustment element is fixed to a first surface, and the first surface is located at a position farther from the second surface with respect to a bottom surface of the module package. . 6. A module package having a predetermined shape, a semiconductor laser for emitting laser light, an optical fiber fixed to the module package, a lens for optically coupling the semiconductor laser and the optical fiber, A substrate on which the semiconductor laser is mounted, having an upper portion and a lower portion bordering the bent portion, a substrate having an upper surface located at a position higher than a lower surface of the lens, A semiconductor laser module comprising: a temperature adjusting element fixed to a lower surface for temperature adjustment. 7. The semiconductor laser module according to claim 4, wherein said first and second surfaces are parallel to said bottom surface. 8. The semiconductor laser module according to claim 4, wherein said first and second surfaces are parallel to each other. 9. A third surface constituting the bent portion and first and second surfaces connected to the third surface are in a vertical relationship to each other, and these first to third surfaces are integrally formed with the substrate. The semiconductor laser module according to claim 4, wherein: 10. The semiconductor laser module according to claim 1, wherein said temperature adjusting element is an electronic cooling element for electronically cooling said semiconductor laser.