JP2003215406A - Semiconductor laser module and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser module which is adaptive to even higher optical coupling efficiency without lowering the yield and made inexpensive by reducing alignment cost and decreasing the number of components and an operation man-hour. <P>SOLUTION: The semiconductor laser module is constituted by fixing a metallic lens holder 4, holding a lens converging or converting the laser light of a semiconductor laser element 1 into pseudo-parallel light, directly on a stem 3 made of copper tungsten by laser welding. A manufacturing method for the semiconductor laser module includes a process of welding and fixing the lens holder 4 directly on the stem 3 by a YAG laser and a process of housing the stem 3 in a package 10 and is characterized by that after peak intensity which is high enough to fuse the copper tungsten material is held, the intensity of the laser lights having the waveforms (14, 16, and 17) used for the YAG laser welding is gradually decreased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device integrated with a lens optical system and a method for manufacturing the same.

[0002]

2. Description of the Related Art An example of a conventional fixing structure for a lens holder of a semiconductor laser module will be described with reference to FIG.

FIG. 13 is a vertical sectional view of a semiconductor laser module. The semiconductor laser device 1 is mounted on a stem 3 made of a copper tungsten material via a heat sink 2 made of aluminum nitride attached by a joining means such as solder. Further, on the stem 3 on the light emitting side of the semiconductor laser element 1, a lens holder 4 accommodating a lens 5 is provided with a welding base made of Kovar, stainless steel or the like fixed on the stem 3 with a silver brazing material 13. Metal 12
To the position where the optical axis is aligned with the semiconductor laser device 1 via
It is fixed by G laser welding (Japanese Patent Laid-Open No. 2000-2).
77784).

Further, the stem 3 is a package 10
Thermionic cooling element 11 fixed to the inner bottom surface by soldering
It is also fixed on the top by soldering. Optical fiber 7
Is aligned with the optical axis of the lens 5 and then fixed to the package 10 together with the ferrule 8 and the ferrule holder 9 for holding the optical fiber 7.

Stainless steel is used as the material of the lens holder 4.

On the other hand, as the material of the stem 3, a copper tungsten material having excellent thermal conductivity is used. This is because in order to control the operating temperature of the semiconductor laser device 1, the heat generated in the semiconductor laser device 1 is transferred to the stem 3 via the heat sink 2, and the thermoelectron cooling arranged under the stem 3 is performed. This is to increase the efficiency of cooling by the element 11.

Irradiation of the YAG laser is applied to the boundary portion between the welding base metal 12 and the lens holder 4, and the laser irradiation at this time is made of stainless steel having a melting point of about 150.
A laser with a rectangular waveform was used with an output heating to 0 ° C.

[0008]

However, in the above-mentioned conventional technique, the lens holder 4 is fixed to the stem 3 via the welding base metal 12 and the silver brazing material 13. Therefore, the welding base metal 12 and the silver brazing material 13
Due to the variation in the dimension, the mounting position of the lens holder 4 with respect to the stem 3 also varies. As a result, the optical coupling state between the semiconductor laser device 1 and the lens 5 also varies, and the alignment cost of the optical fiber 7 increases. Further, in order to cope with higher optical coupling efficiency, a yield will occur. In addition, welding base metal 1
2 and the use of the silver brazing material 13 increase the number of parts and the number of man-hours required to fix the welding base metal 12 to the stem 3, resulting in an increase in the cost of the semiconductor laser module.

An object of the present invention is to eliminate the above-mentioned problems of the prior art, and it is possible to cope with higher optical coupling efficiency without lowering the yield, and also to reduce the alignment cost and the number of parts. And to provide an inexpensive semiconductor laser module by reducing the number of work steps.

[0010]

In view of the above problems, a semiconductor laser module according to a first aspect of the present invention has a semiconductor laser element mounted on a copper-tungsten stem housed in a package, and a laser beam of the semiconductor laser element. It is characterized in that a metal lens holder for holding a lens for condensing light or converting it into pseudo-parallel light is directly laser-welded and fixed onto the stem.

With this structure, the mounting position of the lens holder does not fluctuate due to the fluctuations in the dimensions of the welding base metal and the silver brazing material, so that the optical coupling state between the semiconductor laser element and the lens 5 is also stable.

Next, in a semiconductor laser module according to a second aspect of the present invention, when the fusion width of the stem is A and the fusion height of the lens holder is B, B <A at a welding portion between the stem and the lens holder. <2B.

According to this structure, by setting the melting width in the above relationship, it is possible to suppress thermal shock to the lens holder and the stem during laser irradiation, and to prevent damage to the member.

Next, a semiconductor laser module according to a third aspect of the present invention is characterized in that the thermal expansion coefficient of the metal material forming the lens holder is in the range of 5 × 10 ^{−6 to} 12 × 10 ⁻⁶ / ° C.

According to this structure, since the difference in the coefficient of thermal expansion is small with respect to the coefficient of thermal expansion of copper tungsten of 6.5 × 10 ^{−6 to} 9.5 × 10 ⁻⁶ / ° C., the heat generated during the laser irradiation is small. It is possible to prevent the occurrence of cracks at the welding location due to the difference in expansion coefficient.

Next, the semiconductor laser module according to claim 4 is characterized in that the lens holder is made of Ni-Fe alloy, SF20T or Kovar material.

According to this structure, in the material of the lens holder, since the content of the sulfur component, which may cause the generation of cracks in YAG laser welding, is small, the welded portion in the welded portion due to the difference in the thermal expansion coefficient at the time of laser irradiation. It is possible to prevent the occurrence of cracks.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor module, wherein a lens made of copper-tungsten having a semiconductor laser element mounted thereon is provided with a lens for condensing laser light of the semiconductor laser element or converting it into pseudo-parallel light. And a step of directly fixing the lens holder by welding with a YAG laser and a step of housing the stem in a package, and
The waveform of the laser beam used in the YAG laser welding is characterized in that after the peak intensity sufficient to melt the copper-tungsten material is maintained, the intensity is gradually decreased.

According to this structure, the lens holder can be directly welded and fixed onto the stem without damaging the member.

That is, high thermal conductivity (up to 200 W / m
In order to perform YAG welding of the copper tungsten material having K) and a high melting point (about 3500 ° C.), it is necessary to irradiate laser light having high energy in a short time. That is, it is necessary to use a laser waveform having a high pulse peak and a short pulse width. Here, when the YAG laser light having a rectangular waveform is irradiated, the copper-tungsten material is not gradually cooled after melting at the laser irradiation point, and heat is diffused all at once from the high-temperature laser irradiation point to the entire stem 3. It will be cooled rapidly. As a result, at the laser irradiation point, the copper-tungsten material may be cracked, and the lens holder made of a metal material such as stainless steel having a relatively low melting point may be greatly scuffed.

On the other hand, according to the method of claim 5,
The waveform of the laser beam used in the YAG laser welding is held at a peak intensity sufficient to melt the copper-tungsten material, and then the intensity is gradually reduced to suppress the thermal shock given to the member. Therefore, the lens holder can be directly welded and fixed onto the stem without causing damage to the member.

The semiconductor laser module manufacturing method according to claim 6 is characterized in that, in the YAG laser welding, the stem is irradiated with laser light and the reflected light is irradiated onto the lens holder. To do.

According to this structure, since the laser light applied to the lens holder is reflected light whose intensity is relaxed, the thermal shock given to the lens holder is greatly suppressed, and the lens holder is less likely to be damaged. You can

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
2 and FIG.

FIG. 1 is a perspective view of a semiconductor laser device 1 mounting portion in the semiconductor laser module of the present invention. The semiconductor laser device 1 is mounted on the stem 3 via a heat sink 2 made of aluminum nitride.
Is attached to the stem 3 made of copper tungsten material by a joining means such as solder. Further, on the stem 3 on the light emitting side of the semiconductor laser element 1, a lens holder 4 in which a lens 5 is housed and fixed is formed by laser welding at a welding point 6 at a position where the optical axis is aligned with the semiconductor laser element 1. It is fixed directly. A YAG laser is preferable as the type of laser.

FIG. 2 is a vertical sectional view of the semiconductor laser module of the present invention. The stem 3 is fixed to the thermoelectric cooling element 11, which is fixed to the inner bottom surface of the package 10 made of metal or ceramic, by solder or the like.

As the material of the stem 3, a copper tungsten material having excellent thermal conductivity is used. The lens holder 4 has a coefficient of thermal expansion of 5 × 10 ^{−6 to} 12 × 10.
It is preferable to use a Ni-Fe alloy or SF20T or Kovar material in the range of ^-6 / ° C.

The optical fiber 7 is aligned in the optical axis with the lens 5, and then fixed to the package 10 together with the ferrule 8 and the ferrule holder 9 for holding the optical fiber 7.

A method of welding the lens holder 4 and the stem 3 in the semiconductor laser module constructed as described above will be described with reference to FIGS.

3 to 6 show pulse waveforms of the YAG laser. The horizontal axis represents pulse time and the vertical axis represents pulse intensity.

Copper-tungsten material has good thermal conductivity (~ 2
Since the heat applied by the YAG laser is easily diffused and the melting point is high (about 3500 ° C.), it is necessary to irradiate high energy in a short time.

With reference to FIGS. 3 and 4, the difference in the meltability of the copper tungsten material due to the difference in the YAG laser waveform will be described.

YAG laser pulse waveform 14 shown in FIG.
After holding during a peak having an intensity I ₁ of the time 0 to T _1, is intended to lower the strength for the time T ₁ through T ₂ from I ₁ to 0. On the other hand, the peak from time 0 to T ₁ has sufficient energy to melt the copper tungsten material at the laser irradiation point. Further, the waveform 15 shown in FIG.
It is a rectangular wave that has been frequently used, and has a peak intensity I ₂
And has a peak retention time of T ₃ and has sufficient energy to melt the copper-tungsten material at the laser irradiation point.

When the copper tungsten material is irradiated with YAG laser light having the waveform 14, the peak intensity I ₁ is from time 0 to T _1.
By holding the temperature for a period of time, heat diffuses throughout the stem, and the laser irradiation point temperature reaches the melting point of the copper tungsten material before the temperature of the laser irradiation point falls below the melting point of the copper tungsten material. After melting the laser irradiation point, the laser irradiation point is gradually cooled by gradually decreasing the laser intensity from I ₁ to 0 at time T _{1 to} T ₂ , and the molten copper tungsten material does not generate cracks. Chill and harden.

On the other hand, when the copper tungsten material is irradiated with the YAG laser beam having the waveform 15, the waveform 15 is a rectangular wave having the peak intensity I ₂ and the peak holding time T ₃ , so that the copper tungsten material at the laser irradiation point is melted. However, the temperature at the melting point cannot be gradually lowered, and the laser irradiation point is rapidly cooled, and cracks occur.

From the above, in order to melt the copper-tungsten material without causing cracks, not the conventional rectangular wave but the peak intensity sufficient to melt the copper-tungsten material at the laser irradiation point and the gradually cooled portion are used. It can be seen that the waveform 14 that it has is suitable.

In addition to waveform 15, waveforms 16 and 17 shown in FIGS. 5 and 6, for example, have a peak intensity sufficient to melt the copper-tungsten material at the laser irradiation point and a waveform having a slow cooling portion. If so, it is possible to melt the copper-tungsten material without causing cracks by controlling the peak strength, the peak holding time, and the slow cooling period according to the volume of the copper-tungsten material, the copper content, and the like. .

Next, FIGS. 7 and 8 show laser irradiation positions of the YAG laser light 18. 7 and 8 are views of the lens holder 4 accommodating the stem 3 and the lens 5 as seen from the laser light emitting side. The laser irradiation point 19 includes a stem 3 made of a copper tungsten material and a lens holder 4 (50N) made of metal.
i-Fe or SF20T or Kovar material). At this time, if the laser output is set to an amount of heat that allows the lens holder 4 having a melting point of about 1500 ° C. to appropriately melt, the melting of the stem 3 having a melting point of about 3500 ° C. is insufficient, and the stem 3
The lens holder 4 cannot be welded. On the contrary, when the laser output is set to the amount of heat for melting the copper-tungsten material having the melting point of about 3500 ° C., the laser irradiation point of the lens holder 4 is excessively melted and largely scooped, and the stem 3 and the lens holder 4 are directly welded. It may not be possible to do so.

Therefore, the laser irradiation position is shifted from the contact portion between the stem 3 and the lens holder 4 to the stem 3 side as in the irradiation point 20 shown in FIG. The emitted laser light first enters the stem 3,
The stem 3 is melted moderately. Then, the laser light reflected by the stem 3 is incident on the lens holder 4. Energy is used to melt the copper-tungsten material, and the weakened laser light does not greatly penetrate the lens holder 4 and melts appropriately. By the above operation, the appropriately molten copper tungsten material and the lens holder 4 are alloyed and welded.

The laser irradiation position and the incident angle of the laser light on the stem 3 at this time will be described with reference to FIG. FIG. 9 is a vertical cross-sectional view of the YAG laser welded portion of the stem 3 and the lens holder 4, in which the shaded portion 22 and the shaded portion 2 are shown.
3 and a shaded portion 24 respectively indicate a melted portion of the YAG laser light 18 melted into the stem 3, a melted portion of the YAG laser light 18 melted into the lens holder 4, and an alloy portion of the stem 3 and the lens holder 4. Further, A represents the melting width on the side of the stem 3, and B represents the melting height on the side of the lens holder 4.

The angle and irradiation position of the YAG laser beam 18 are preferably adjusted so that the relationship between A and B is B <A <2B. By adjusting in this way, it is possible to suppress thermal shock to the lens holder and the stem during laser irradiation to be low, and to prevent damage to members. On the other hand, A and B
If the relation of B> A and A> 2B, cracks may occur at the welded portion.

Next, the lens holder 4 has a coefficient of thermal expansion of 6.5 × 10 ^{−6 to} 9.5 × 10.
Against ^-6 / ° C. Copper tungsten material in the range of, it is preferable to use a material having a thermal expansion coefficient in the range of ^{5 × 10 -6 ~12 × 10 -6} / ℃.

This is because if there is a difference in the coefficient of thermal expansion between the metals to be welded in YAG welding, a difference in the rate of expansion and contraction between the metals to be welded will occur during the heating and cooling process during welding, and cracks in the welded portion will occur. Occurs. Therefore, in YAG welding, it is preferable that the difference in thermal expansion coefficient between the metals to be welded is small.

Here, the coefficient of thermal expansion is 6.5 × 10 ^−6.
If it is less than / ° C or exceeds 12 × 10 ^-6 / ° C, cracks may occur in the welded portion as described above.

As a metal having a coefficient of thermal expansion within the above range,
Furthermore, Ni-Fe alloy or SF20T (coefficient of thermal expansion 1
1 × 10 ⁻⁶ / ° C .: Ferritic stainless steel, chemical composition: C ≦ 0.05 [wt%], Si ≦ 1 [wt%],
Mn ≦ 2 [wt%], P ≦ 0.05 [wt%],
S ≧ 0.15 [wt%], Cr = 19 to 21 [wt]
%], Mo = 1.5 to 2.5 [wt%], Pb =
0.1-0.3 [wt%], Te = 0.01-0.07
[Wt%]) or Kovar material (coefficient of thermal expansion 5.3 × 10
^-6 / ° C.) Is preferably used. The reason is YA
This is because the content of the sulfur component, which may cause the generation of cracks in G laser welding, is small. Ni-F
As an e-alloy, especially 50Ni-Fe (coefficient of thermal expansion 9.4
× 10 ^-6 / ° C) is preferable.

Next, with reference to FIG. 2, a procedure for manufacturing the semiconductor laser module of the present invention will be described.

The semiconductor laser device 1 is soldered and fixed to the heat sink 2 made of aluminum nitride. The heat sink 2 to which the semiconductor laser device 1 is fixed is soldered and fixed onto the stem 3 made of a copper tungsten material. Furthermore, lens 5
The lens holder 4 storing and fixing the lens is aligned at a position aligned with the optical axis of the semiconductor element 1, and the YA is directly attached onto the stem 3.
G Laser welding Fix.

The waveform of the YAG laser beam used for welding the stem 3 and the lens holder 4 has a peak intensity sufficient to melt the copper tungsten material and a waveform having a slow cooling portion. For example, FIGS. Waveforms 14, 16, 1 shown in
It is preferable to use a waveform having a waveform like 7.

The irradiation position of the YAG laser irradiation is shown in FIG.
It is better to shift it to the stem 3 side as shown in.

At this time, the irradiation angle and the irradiation position with respect to the stem 3 are as shown in FIG.
It is preferable to select the irradiation angle and irradiation position so that <A <2B.

Then, as described above, the semiconductor laser device 1,
The stem 3 on which the heat sink 2 and the lens holder 4 accommodating the lens 5 are mounted is fixed on the thermoelectric cooling element 11 by soldering, and the thermoelectric cooling element 11 is also fixed on the inner bottom surface of the package 10 by soldering.

Next, after aligning the optical fiber 7 held by the ferrule 8 so that the optical axis is aligned with the lens 5, the ferrule 8 is YAG-welded and fixed to the ferrule holder 9, and the ferrule holder 9 is fixed to the package 10. Fix by YAG welding. Finally, a canopy (not shown) is placed on the upper part of the package 10 and welded and fixed to the package 10 by seam welding.

[0053]

EXAMPLE As the present example, the semiconductor laser module shown in FIG. 2 was manufactured. In FIG. 2, the semiconductor laser device 1 is mounted on a heat sink 2 made of aluminum nitride.
Mounted and fixed with u-Sn solder. The heat sink 2 having the semiconductor laser device 1 mounted thereon was fixed to a stem 3 made of a copper tungsten material with Pb-Sn solder. Then, the lens holder 4 containing the lens 5 and made of SF20T was placed at a position aligned with the optical axis of the semiconductor laser device 1 and directly joined to the stem 3 by YAG welding.

The waveform of the YAG laser used for welding the stem 3 and the lens holder 4 is shown as a waveform 21 in FIG.
The peak intensity is I ₃ , and the peak retention time is 3 msec.
Is. Also, when the pulse time is 5 msec, the intensity is 1/3 ×
The waveform is controlled so that the intensity becomes 0 when I ₃ and the pulse time is 10 msec. Further, the peak intensity I ₃ is controlled so that the total irradiation energy amount becomes 15 J in the time of 0 to 10 msec.

The laser irradiation position is shown in FIG. The YAG laser light is 1 mm from the contact portion between the stem 3 and the lens holder 4.
The irradiation angle is 18 relative to the stem 3
It was °. First, by irradiating the stem 3 made of a copper tungsten material with the laser light and irradiating the reflected light on the lens holder 4, both the stem 3 and the lens holder 4 are melted and alloyed without excess or deficiency. Further, by using the peak strength sufficient to melt the copper-tungsten material and the corrugated portion 21 having the gradually cooled portion, the generation of cracks at the welded portion could be prevented.

Then, as described above, the semiconductor laser device 1,
The stem 3 having the lens holder 4 accommodating the heat sink 2 and the lens 5 mounted thereon is fixed to the thermoelectric cooling element 11 with In-Pb-Ag solder, and the thermoelectron cooling element 11 is also fixed with In-Pb-Ag solder. It is fixed in the package 10.

Then, after the optical fiber 7 held by the ferrule 8 is aligned so that the optical axis is aligned with the lens 5,
The ferrule 8 was fixed to the ferrule holder 9 by YAG welding, and the ferrule holder 9 was fixed to the package 10 by YAG welding.

FIG. 12 shows the standardized coupling efficiency when the lens 5 is deviated perpendicularly to the optical axis in the optimal coupling state and then the optical fiber 7 is aligned. In the conventional semiconductor laser module using the welding base metal 12 and the silver brazing material 13 as a comparative example, the deviation of the lens 5 in the direction perpendicular to the optical axis was ± 40 μm, and the deterioration amount of the optical coupling efficiency was 2 dB. On the other hand, in the case of the present embodiment, the deviation of the lens 5 in the direction perpendicular to the optical axis can be suppressed to ± 20 μm, and the deterioration amount of the optical coupling efficiency can be suppressed to 0.5 dB.

As described above, the waveform of the YAG laser is changed to the waveform 2
1 and the laser irradiation point is set to the position shown in FIG. 11 to move the lens holder 4 and the stem 3 to Y
Welding base metal 12 that has been required in the past with AG welding enabled
Since the mounting of the lens 5 on the semiconductor laser device 1 is not necessary, the variation in the optical coupling state between the semiconductor laser device 1 and the lens 5 can be suppressed, and the alignment cost of the optical fiber 7 can be reduced. Became. Also,
By suppressing the deterioration amount of the optical coupling efficiency without using means such as tightening the precision of the components, it has become possible to cope with higher optical coupling efficiency without increasing the component cost. Further, the cost of the semiconductor laser module can be reduced because the number of parts is reduced by eliminating the need for the welding base metal 12 and the number of man-hours for fixing the welding base metal 12 to the stem 3 is reduced.

[0060]

As described above, according to the semiconductor laser module of the present invention, the mounting position of the lens holder varies because the lens holder made of metal is directly laser-welded and fixed on the stem made of copper tungsten. Therefore, the optical coupling state between the semiconductor laser device and the lens is also stable. Therefore, it is possible to reduce the centering cost of the optical fiber, and by suppressing the deterioration amount of the optical coupling efficiency without using means such as tightening the accuracy of the parts,
It is possible to cope with higher optical coupling efficiency without increasing the component cost. Further, the cost of the semiconductor laser module can be reduced because the number of parts is reduced by eliminating the need for welding base metal and the number of man-hours for fixing the welding base metal to the stem is reduced.

Further, in the welded portion between the stem and the lens holder of this semiconductor laser module, when the melting width of the stem is A and the melting height of the lens holder is B, B <A <2B. In this case, it is possible to suppress thermal shock to the lens holder and the stem during laser irradiation to be low, and to prevent damage to the members.

Further, in the semiconductor laser module, when the thermal expansion coefficient of the metal material constituting the lens holder is in the range of 5 × 10 ^{−6 to} 12 × 10 ⁻⁶ / ° C., the thermal expansion coefficient of copper tungsten is 6. 5 × 10 ^{−6 to} 9.5 × 10
^Since the difference in the coefficient of thermal expansion is small with respect to ⁻⁶ / ° C., it is possible to prevent the occurrence of cracks due to the difference in the coefficient of thermal expansion during the laser irradiation.

In the semiconductor laser module, when the lens holder is made of Ni-Fe alloy, SF20T or Kovar material, the component of the lens holder has a sulfur component which may induce cracks in YAG laser welding. Since the content of is small, it is possible to prevent the occurrence of cracks at the welded portion due to the difference in thermal expansion coefficient during the laser irradiation.

Next, according to the method of manufacturing the semiconductor laser module of the present invention, the waveform of the laser beam when the lens holder is directly welded and fixed on the copper-tungsten stem by the YAG laser is changed to the copper-tungsten material. By holding the peak strength sufficient for melting and then gradually lowering the strength, the lens holder can be directly welded and fixed onto the stem without causing damage to the member.

Further, in this method of manufacturing a semiconductor laser module, in the YAG laser welding, when the stem is irradiated with laser light and the reflected light thereof is irradiated onto the lens holder, the lens holder is irradiated with the laser light. Since the laser light is reflected light whose intensity is moderated, it is possible to greatly suppress the thermal shock particularly given to the lens holder and make it difficult to damage the lens holder.

[Brief description of drawings]

FIG. 1 is a perspective view of a semiconductor laser device mounting portion of the present invention.

FIG. 2 is a vertical sectional view of a semiconductor laser module of the present invention.

FIG. 3 is a diagram showing the relationship between the pulse time and the pulse intensity of the YAG laser waveform of the present invention.

FIG. 4 is a diagram showing a relationship between pulse time and pulse intensity of a conventional YAG laser waveform.

FIG. 5 is a diagram showing the relationship between the pulse time and the pulse intensity of the YAG laser waveform of the present invention.

FIG. 6 is a diagram showing the relationship between the pulse time and the pulse intensity of the YAG laser waveform of the present invention.

FIG. 7 is a diagram showing an irradiation position of a conventional YAG laser beam.

FIG. 8 is a diagram showing irradiation positions of YAG laser light of the present invention.

FIG. 9 is a diagram showing the relationship between the amount of penetration of the YAG laser light of the present invention with respect to the stem and the lens holder.

FIG. 10 is a diagram showing the relationship between the pulse time and the pulse intensity of the YAG laser waveform of the present invention.

FIG. 11 is a diagram showing irradiation positions of YAG laser light of the present invention.

FIG. 12 is a diagram showing a tolerance curve of a lens in a vertical direction.

FIG. 13 is a vertical sectional view of a conventional semiconductor laser module.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser element 2 ... Heat sink 3 ... Stem 4 ... Lens holder 5 ... Lens 6 ... Welding point 7 ... Optical fiber 8 ... Ferrule 9 ... Ferrule holder 10 ... Package 11 ... Thermoelectric cooling element 12 ... Welding base metal 13 ... Silver Brazing material 14 ... Pulse waveform 15 ... Square wave 16 ... Pulse waveform 17 ... Pulse waveform 18 ... YAG laser light 19 ... Laser irradiation point 20 ... Laser irradiation point 21 ... YAG laser waveform 22 ... 23 ... Melting part of YAG laser light 18 with respect to lens holder 4 ... Alloy part of stem 3 and lens holder 4

Claims (6)

[Claims] 1. A metal lens which mounts a semiconductor laser element on a copper-tungsten stem housed in a package and holds a lens for condensing or converting laser light of the semiconductor laser element into pseudo-parallel light. A semiconductor laser module in which a holder is directly laser-welded and fixed onto the stem. 2. At the welded portion between the stem and the lens holder, B <A <2B, where A is the melting width of the stem and B is the melting height of the lens holder. The semiconductor laser module according to claim 1. 3. The semiconductor laser module according to claim 1, wherein the metal material forming the lens holder has a coefficient of thermal expansion of 5 × 10 ^{−6 to} 12 × 10 ⁻⁶ / ° C. . 4. The lens holder is Ni-Fe alloy or S
4. The semiconductor laser module according to claim 1, wherein the semiconductor laser module is made of F20T or Kovar material. 5. A lens holder for holding a lens for condensing laser light of the semiconductor laser element or converting it into pseudo-parallel light is directly fixed to a stem made of copper-tungsten on which a semiconductor laser element is mounted by welding with a YAG laser. And the step of storing this stem in the package,
Moreover, the waveform of the laser beam used in the YAG laser welding is such that a peak intensity sufficient to melt the copper-tungsten material is maintained and then the intensity is gradually decreased. Production method. 6. The method of manufacturing a semiconductor laser module according to claim 5, wherein in the YAG laser welding, laser light is applied to the stem and reflected light is applied to the lens holder. .