JP2000277843A - Semiconductor laser module and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser module, in which fitting of a lens optical system to a base, on which an LD element is mounted is realized by welding a lens holder, and reliability for temperature cycling is improved, and a method for manufacturing it. SOLUTION: A base 130 on which an LD element 110 is mounted is composed of a material of high thermal conductivity, and further a welding base metal 132 of superior weldability is provided to the part of the base into a body, and a lens optical system 120, that is optically coupled to the LD element 110, is welded to the welding base metal 132 with a lens holder 121 (a lens tube 122 and a lens-fixing fitting 123) composed of a material whose thermal expansion coefficient is substantially equal to that of the welding base metal 132. Heat generated at the LD element 110 is rapidly radiated through the base 130, and deviation of the optical axis of the LD element 110 from that of the lens optical system 120 accompanying the thermal expansion variation of the base 130 and the lens holder 121 caused by heat generation of the LD element 110 is solved, so that reliability with respect to temperature cycling is improved.

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 in which a semiconductor laser device (hereinafter referred to as an LD device) and a lens optical system are integrated.
The present invention relates to a semiconductor laser module on which an element is mounted and a method for manufacturing the same.

[0002]

2. Description of the Related Art A semiconductor laser module is used in an optical fiber communication system, in which laser light emitted from an LD element is optically coupled to an optical fiber by a lens optical system and transmitted through the optical fiber. Therefore, this type of semiconductor laser module has a configuration in which the LD element and the lens optical system are mounted on a metal base with the emission optical axis of the LD element and the optical axis of the lens optical system aligned. ing. FIG. 8 is a cross-sectional view of a conventional semiconductor laser module, in which an LD element 110 is made of aluminum nitride (Al).
N) is mounted on a heat sink 111 composed of
Is fixed on a base 130 'composed of. The base 1 at a position facing the LD element 110
A lens optical system 120 assembled to a lens holder 121 composed of a lens barrel 122 made of steel and a lens fixture 123 is integrally mounted on 30 ′ by welding. Then, the module 10 having the above configuration
0 ′ is mounted in a module case 200 including a second lens optical system 220 optically coupled to the optical fiber 230, and is mounted on a cooler (cooling device) 210 such as a Peltier element in the module case 200. Assembled. In this assembled state, the lens optical system 120 is optically coupled to the second lens optical system 220, and the light emitted from the LD element 110 is transmitted through the lens optical system 120 and the second lens optical system 220. The fiber 230 is introduced.

In assembling such a semiconductor laser module, as a technique for aligning the optical axis of the LD element 110 with the optical axis of the lens optical system 120, first, the LD element 110 is mounted on a base 130 'and then the LD element 110 emits light. It is operated to position the optical axis of the lens optical system 120 so that the optical axis of the lens optical system 120 coincides with the laser beam emitted from the LD element 110, and then the lens holder 121 of the lens optical system 120 is welded to the base 130 '. The method of doing is taken. Here, in the semiconductor laser module, as described above, Kovar is used as the material of the base 130 '. Since the lens holder 121 is fixed to the base 130 'while aligning the optical axis of the lens optical system 120 with the LD element 110 as described above, a welding YAG laser having good workability is used. This is because welding is performed, and Kovar is selected as a metal material that can be subjected to the YAG welding. By the way,
With the technique of brazing the lens holder 121 to the base 130 ', it is difficult to fix the lens holder 121 with high accuracy.

In recent years, in an optical fiber communication system, a technique has been proposed in which an optical signal transmitted through an optical fiber for forming an optical transmission line is amplified by an optical fiber amplifier. This optical amplifier is an optical fiber amplifier (hereinafter referred to as ED) doped with erbium as a rare earth element.
The EDFA is supplied with high-power pumping light for pumping signal light. Although the semiconductor laser module having the above-described configuration is used as the semiconductor laser module for excitation for supplying the excitation light, it is necessary to supply a large current to the LD element in order to obtain a required high optical output. The heat value at the point becomes remarkable. Conventionally, as shown in FIG. 8, a base 130 ′ on which an LD element 110 is mounted is mounted in a module case 200 via a cooler 210 in order to enhance the heat radiation effect of heat generated by the LD element. Element 1
The heat generated in 10 is transmitted to the base 130 ′ via the heat sink 111, and can be further cooled by the cooler 210 arranged below the base 130 ′.

[0005] However, as described above, the base 1
In the conventional semiconductor laser module using Kovar as the material of 30 ′, the thermal conductivity of Kovar is 17 W / mK.
For example, when the semiconductor laser module for excitation of an EDFA is driven at 0.5 A × 2 V = 1 W, the required cooling characteristics (ΔT = 40 K at Tc = 65 ° C.) are satisfied. Can not do. Therefore, as the metal material of the base 130 'of the semiconductor module, copper tungsten (CuW) having a thermal conductivity (up to 200 W / mK) which is much higher than that of Kovar is used. For example, Japanese Patent Application Laid-Open No. Hei 7-140362 describes that the use of copper tungsten or silicon carbide as a base improves the heat radiation characteristics of the LD element and achieves high output operation.

Further, when copper tungsten is used for the base, it is impossible to attach a lens fixing bracket to the copper tungsten by YAG welding, so that an LD element is first fixed to the base as in the conventional semiconductor laser module. In addition, it is difficult to apply the present invention to a semiconductor module having a structure in which the lens holder of the lens optical system is mounted on the base while the optical axis of the lens optical system is aligned with the optical axis of the LD element. To solve such a problem, as shown by a chain line in FIG. 8, a metal which can be YAG-welded in advance, for example, a Kovar is used as a welding base metal 132 'by brazing on the surface of the base 130' for attaching the lens holder. The lens holder 121 is integrated with the welding base metal 132 ′.
YAG welding may be considered. In this way, YAG
For example, Japanese Patent Application Laid-Open No. 9-138329 discloses a technique of using a cover for a part of a component to enable welding.
There is a technique described in Japanese Unexamined Patent Application Publication No. HEI 9-86.

[0007]

However, in the case where a cover is used as the welding base metal 132 'for welding the lens holder 121 to the base 130', the lens barrel 122 constituting the lens holder 121 is not used. Thermal expansion coefficient of steel (SF20T) (11 × 10 ^-6 / ° C),
Stainless steel (SUS304) for lens fixing bracket 123
The thermal expansion coefficient (18 × 10 ⁻⁶ / ° C.) of Kovar as the base metal 132 ′ for welding (5.3 × 10
⁻⁶ / ° C.), the LD element 110
The heat generated in step (1) causes thermal stress between the lens fixture 123 and the lens barrel 122 and the welding base metal 132 ', and the thermal stress changes the mounting position of the lens holder 121 with respect to the base 130', and
The optical axis between the element 110 and the lens optical system 120 may be shifted. In addition, the lower-value metal 132 is deformed by the difference between the coefficient of thermal expansion of copper tungsten of the base 130 '(8.5 × 10 ^-6 / ° C.) and the coefficient of thermal expansion of the base metal of the weld 132' and the cobar. Lens holder 121
May be changed. like this,
The optical axis deviation due to the difference in the thermal expansion coefficient cannot be ignored when the above-described semiconductor laser module for pumping the EDFA is configured beyond the margin of the optical coupling design. Will result in a decrease in sex.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor laser module which realizes mounting of a lens holder of a lens optical system mounted on a base by welding and which has improved reliability in a thermal environment test such as a temperature cycle, and a method of manufacturing the same. To provide.

[0009]

In a semiconductor laser module according to the present invention, a base on which an LD element is mounted is made of a material having high thermal conductivity, and a base metal having good weldability is integrally formed on a part of the base. Wherein the lens optical system mounted on the base is welded to the base metal by a lens holder made of a material having a thermal expansion coefficient substantially equal to that of the base metal. Here, the base is made of copper tungsten (CuW). Further, the welding base metal is made of a material having a thermal expansion coefficient close to that of the base. Further, the lens holder includes a lens barrel holding a lens and a lens fixing bracket holding the lens barrel, and at least the lens fixing bracket is formed of the same material as the base metal for welding. Is preferred. In this case, the welding base metal and the lens fixing bracket are made of stainless steel (SUS43).
0). Further, the semiconductor laser module of the present invention is built in a module case having a second lens optical system optically coupled to an optical fiber, and is provided in the lens optical system of the semiconductor laser module and the module case. It is preferable that the second lens optical system be optically coupled.

According to the method of manufacturing a semiconductor laser module of the present invention, there is provided a step of integrally providing a base metal made of a material having a high thermal conductivity with a base metal which can be laser-welded, and the other part of the base. Mounting a semiconductor laser element on the substrate, and aligning a lens optical system with a laser beam emitted from the semiconductor laser element by causing the semiconductor laser to emit light, and holding the lens holder of the lens optical system on the welding base. The method includes a step of performing laser welding on a metal, wherein the lens holder and the base metal to be welded are made of materials having substantially equal thermal expansion coefficients. The lens optical system includes a lens barrel that holds a lens, and a lens fixture that holds the lens barrel. After the lens fixture is laser-welded, the lens mirror is attached to the lens fixture. Preferably, the tube is laser welded.

In the semiconductor laser module according to the present invention, the base metal is provided on the base, so that when a material having high thermal conductivity is selected as the base, even when welding of the lens holder to the base is difficult, the lens holder is provided. Can be attached to the base by welding to the base metal. Further, by using a material having a thermal expansion coefficient substantially equal to that of the metal to be welded as the lens holder, it is possible to suppress the optical axis shift between the LD element and the lens optical system even by the heat generated by the LD element. Further, by using a material having a thermal expansion coefficient close to that of the base as the base metal for welding, it is possible to further suppress the optical axis deviation.

As a technique close to the present invention, Japanese Patent Laid-Open No.
Japanese Patent No. 254723 discloses a technique in which a cylindrical member made of a material having good weldability such as stainless steel or Kovar is attached to a hole of an optical base made of copper tungsten, and a lens fixing bracket is welded there. Has been described. For this reason, it is common with the present invention in that stainless steel is used as a material to be attached to the base side.
Stainless steel is configured as a cylindrical member and inserted into a hole in the optical base. Therefore, even when the cylindrical member thermally expands due to the temperature cycle, the cylindrical member is deformed symmetrically with respect to the central axis, so that there is no influence on the optical axis deviation of the optical fiber held by the cylindrical member. However, when stainless steel is simply used as the welding base metal having no cylindrical member as in the present invention, symmetry with respect to the central axis as in the case of the cylindrical member cannot be obtained. It is impossible to prevent displacement. Further, the publication does not disclose that the lens holder is made of a material having a thermal expansion coefficient substantially equal to that of the lens fixing bracket.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a part of a semiconductor laser module according to the present invention, and FIGS. 2 and 3 are a plan view and a sectional view of the assembled state. The semiconductor laser module 1 includes a semiconductor laser module 100 in a narrow sense in which an LD element 110 and a lens optical system 120 are integrally formed, and a module case 200 containing the semiconductor laser module 100 therein. Here, the semiconductor laser module 100 in a narrow sense is referred to as an LD / lens module here. The LD / lens module 100 has the LD element 110 and the lens optical system 120 mounted on a base 130 made of copper tungsten (CuW). The LD element 110 is made of aluminum nitride (Al).
N) on a heat sink 111 made of N)
And the heat sink 11
Reference numeral 1 denotes a base 13 protruding from the upper surface of the base 130.
1 is brazed to the upper surface by a metal brazing material 113. A circuit board 140 is mounted on another portion of the upper surface of the base 131 of the base 130,
The D element 110 is wire-bonded to the circuit board 140 with a thin metal wire 141, and power is supplied through the circuit board 140.

On the other hand, stainless steel (SU) is provided on the upper surface of the base 130 at a position facing the LD element 110.
The plate-shaped welding base metal 132 made of S430) is made of Ag.
-Integrated by brazing with a Cu brazing material 133 or the like. The lens holder 121 of the lens optical system 120 is fixed on the welding base metal 132. The lens holder 121 is composed of a lens barrel 122 and a lens fixture 123, and one or more lenses constituting the lens optical system 120 are made of a steel material (SF20T) having an outer shape close to a rectangle. The lens barrel 122 is formed in the lens barrel 122, and is fixed to the lens fixture 123 made of stainless steel (SUS430) having an upward U-shape by YAG welding. The lens fixture 123 is fixed to the upper surface of the welding base metal 132 by YAG welding. The location indicated by the black circle in FIG. 2 is the location of YAG welding. Note that the lens optical system 120 is provided with the LD element 1.
10 at the optical axis position coincident with the optical axis
It goes without saying that the light emitting surface of the LD element 110 is positioned at the focal position of 20.

The LD / lens module 100 having such a structure is housed in the module case 200. The module case 200 is formed of a metal material in a box shape, and a cooler 210 formed of a Peltier element is disposed on an inner bottom surface of the module case 200. The base 130 of the LD / lens module 100 is formed of the cooler 210.
Mounted on top. Further, a circular opening 201 is opened on one side surface of the module case 200, and a second lens optical system 220 is fixed in the opening 201. The second lens optical system 220 includes the LD
A lens barrel 221 made of stainless steel similar to the lens fixing bracket 123 of the lens module 100 is inserted into the opening 201 and fixed with a solder material or the like. The lens barrel 221 has an optical fiber 23.
0 is provided integrally with a cylindrical holder 222 for fixing a pigtail 231 provided at one end of the optical fiber 230. The pigtail 231 of the optical fiber 230 aligns the optical axis with the second lens optical system 220. In this state, it is fixed to the holder 222 by YAG welding. In addition,
It goes without saying that the optical fiber 230 has one end face positioned at the focal position of the second lens optical system 220. In this embodiment, a lead terminal 240 connected to a power supply circuit (not shown) is provided in the module case 200, and the lead terminal 240 extends to the inside of the module case 200. Is wire-bonded to the circuit board 140 of the LD / lens module 100 with a thin metal wire 241.

A method of assembling the LD / lens module 100 among the semiconductor laser modules configured as described above will be described with reference to FIGS. First, in FIG. 4, as a preliminary step, stainless steel (SU) is formed on a part of the upper surface of the base 130 made of copper tungsten.
The welding base metal 132 made of S430) is integrated by bonding using the Ag-Cu brazing material 133.
The LD element 110 to be mounted is soldered to the heat sink 111 with an Au-Sn solder (112). Then, the base 130 is fixed to a work stage (not shown), and the heat sink 111 on which the LD element 110 is mounted is gripped by an actuator A1 to attach Au- on the upper surface of the base 131 of the base 130. The solder is stopped by the Sn solder 113. At this time, the LD element 110 is used, for example, by using a positioning line or the like formed on the upper surface of the base 131 or by mechanically positioning the actuator A1 that holds the heat sink 111.
By setting the position of the heat sink 111 in the plane XY direction, positioning with respect to the base 130 placed on the stage is performed. Here, the X direction is the optical axis direction of the LD element 110, and the Y direction is a direction orthogonal to the X direction on a plane.

Next, as shown in FIG. 5, the LD element 110 mounted on the base 131 is wire-bonded to the conductive portion of the circuit board 140 mounted on the upper surface of the base 131 by a thin metal wire 141. And make an electrical connection. Then, an upward U-shaped lens fixing bracket 123 is placed on the welding base metal 132 integrated with the base 130, and a lens barrel 122 is disposed between both side walls of the lens fixing bracket 123. I do. The projection 124 on the upper surface of the lens barrel 122 is held by the actuator A2 so that the lens barrel 122 and the lens fixture 123 can be integrally moved in the plane Y direction on the upper surface of the base metal 132 for welding. Set the status to A probe P connected to a power supply unit (not shown) is brought into contact with the base 130 and the circuit board 140 to supply power to the LD element 110 so that the LD element 110 emits light. Then, the light transmitted through the lens optical system 120 and the second lens optical system 220 and condensed at the optical axis position of the lens optical system 120 opposite to the LD element 110 is detected through the measuring optical fiber F. In addition, photometry is performed by the photodetector PD, and the optical axis of the lens optical system 120 is adjusted so that the photometric value is maximized. Here, the optical axis of the lens optical system 120 with respect to the LD element 110 is adjusted by integrally moving the lens barrel 122 and the lens fixture 123 in the plane Y direction by the actuator A2. At the position where the optical axes are aligned, a black circle X
As shown by 1, a YAG laser is irradiated from the YAG laser device YL to a plurality of locations at the boundary between the lens fixing bracket and the welding base metal, and the lens fixing bracket 123 is moved to the welding base metal 132.
YAG welding. At this time, since the lens fixing bracket 123 and the welding base metal 132 are the same stainless steel,
AG welding is possible.

Thereafter, as shown in FIG.
In the lens fixing bracket 123 fixed on 32,
The lens barrel 122 is finely aligned with the LD element 110 so that only the lens barrel 122 can be moved in the plane X direction and the Z direction (vertical direction) by the actuator A2. Also in this case, the probe P
The LD element 110 is caused to emit light by power supply from the lens optical system F and the lens optical system 12 using the optical fiber F and the photodetector PD.
The position where the photometric value transmitted and condensed through the zero and second lens optical systems 220 is maximum is set. Then, at the position where the optical axes are aligned, as shown by a black circle X2 in the figure, the YAG laser is irradiated from the YAG laser device YL to a plurality of locations on the boundary between the lens barrel 122 and the lens fixing bracket 123, and the lens barrel 122 is attached to lens fixing bracket 123 by Y
AG welding. At this time, since the lens barrel 122 is made of a steel material, YAG welding with the lens fixture 123 is possible. Thus, the mounting of the lens optical system 120 having the optical axis aligned with the LD element 110 on the base 130 is completed.

It should be noted that the LD assembled as described above
The lens module 100 includes the module case 20.
It is mounted and fixed on a cooler 210 which is provided in advance in the inside of the cooler 210. In that case, the LD / lens module 100
The optical axis of the LD element 110 and the lens optical system 120 is aligned with the second lens optical system 220 provided in the module case 200. In the optical axis alignment at this time, by performing photometry through the optical fiber 230 connected to the second lens optical system 220, an appropriate optical axis alignment can be performed as described above.

According to the above manufacturing process, the thermal conductivity is up to
Even though the base 130 of the LD / lens module 100 is formed of copper tungsten, which is larger than the cover and is difficult to fix by YAG welding, the lens holder 121, that is, the lens fixing bracket 123 is formed on the base 1.
Since the welding base metal 132 made of stainless steel capable of YAG welding is present at the portion fixed to 30, the YAG welding of both can be performed. Of course, the lens barrel 12
YAG welding is also possible when fixing 2 to the lens fixing bracket 123. Therefore, when assembling as described above, LD
The element 110 is caused to emit light, and the emitted light is used to position the lens barrel 122 and the lens fixture 123 while performing optical axis alignment with the lens optical system 120. Further, YAG welding of the lens fixture 123 and the lens barrel 122 is performed. , And assembling of the LD / lens module 100 with the optical axis aligned with high precision becomes possible. Incidentally, the lens fixing bracket 123 and the lens barrel 122
Is fixed to the base 130 with a brazing material, an adhesive, or the like, misalignment tends to occur when the brazing material or the adhesive after the alignment is solidified, and it is difficult to perform high-precision positioning and fixing.

Therefore, in the semiconductor laser module 1 assembled in this manner, the heat generated when the LD element 110 emits light is quickly transferred by the base 130 made of copper tungsten having a high thermal conductivity, and is provided on the lower surface. The cooling can be performed by the cooler 210, and when configured as an excitation semiconductor laser module for an EDFA, required cooling characteristics can be satisfied even when the optical output of the LD element 110 is increased.

On the other hand, as shown in FIG. 7A, the material of each part constituting the LD / lens module 100 and the thermal expansion coefficient thereof are shown in FIG. 10 ^-6 / ° C), the stainless steel (S
US430) has a thermal expansion coefficient of (11 × 10 ⁻⁶ / ° C.), and the steel (SF20T) of the lens barrel 122 has a thermal expansion coefficient of (11 × 10 ⁻⁶ / ° C.). Therefore, the base 130, the base metal 132, the lens fixture 12
3. The difference in the coefficient of thermal expansion between the lens barrels 122 is (2.5 × 10 ⁻⁶ / ° C., 0, 0).
Even when a thermal cycle is caused by the heat generation of the LD element 110, the thermal stress applied to the lens fixture 123 and the lens barrel 122 can be reduced, and the deformation of the lens fixture 123 and the lens barrel 122 due to the thermal stress is suppressed. You. Thereby, the displacement of the optical axis between the LD element 110 and the lens optical system 120 due to the thermal cycle can be suppressed to a level that does not cause harm, and the reliability of the semiconductor laser module is improved.

FIG. 7B shows a comparative example of a conventional semiconductor laser module provided with a welding base metal 132 'of Kovar indicated by a chain line in FIG. Has a coefficient of thermal expansion of (5.3 ×
10 ⁻⁶ / ° C.), and the coefficient of thermal expansion of stainless steel (SUS304) as the lens fixing bracket 123 is (18 × 1).
0 ⁻⁶ / ° C.), the difference between the coefficients of thermal expansion among the base 130 ′, the base metal 132 ′, the lens fixture 123, and the lens barrel 122 is (3.2 ×).
^{10 -6 /℃,12.7×10 -6 / ℃, 7} × 10 -6 / ℃)
When a thermal cycle is caused by the heat generation of the LD element 110, the thermal stress applied to the lens fixture 123 and the lens barrel 122 is large, and the optical axis of the lens fixture 123 and the lens barrel 122 due to the thermal stress. The shift will be significant. Note that, in this case, the same stainless steel (SUS4
Even when 30) is used, the difference in the coefficient of thermal expansion from the cover is (5.7 × 10 ⁻⁶ / ° C.), and the lens fixing bracket 123 is used.
It is difficult to suppress the optical axis shift due to thermal stress in the lens barrel 122.

Incidentally, also in the semiconductor laser module 1 of the above embodiment, the optical output of the LD
In this case, the influence of heat generated by the LD element 110 is large, and a slight optical axis shift occurs between the lens optical system 120 of the LD / lens module 100 and the second lens optical system 220 of the module case 200. May occur. However, in this semiconductor laser module, the lens optical system 120 and the second lens optical system 2
As shown in FIG. 3, optical coupling with the optical system 20 is caused by a parallel light flux, so that an optical axis shift in a direction perpendicular to the optical axis occurs between the lens optical system 120 and the second lens optical system 220. Even in this case, the optical coupling efficiency between the LD element 110 and the optical fiber 230 hardly decreases due to the optical axis shift, and high optical coupling efficiency can be maintained.

Here, in the above embodiment, stainless steel (SUS430) is used as the base metal for welding, but a material capable of welding, particularly laser welding such as YAG welding, and copper tungsten constituting the base If the material has a thermal expansion coefficient close to that of the material, the same can be applied. Further, the lens fixing bracket and the lens barrel need not have the same thermal expansion coefficient as those of the base metal to be welded as long as they are substantially the same. Therefore, these members need not necessarily be formed of the same material. Furthermore, in the above-described embodiment, the lens holder is formed separately from the lens barrel and the lens fixing bracket in order to easily perform the optical axis alignment of the lens optical system. It is also possible to configure the lens holder as one block. In this case, since the entire lens holder is made of one material, the influence of the optical axis shift due to the thermal expansion coefficient can be further reduced as compared with the above embodiment.

[0026]

As described above, according to the present invention, the base on which the LD element is mounted is made of a material having high thermal conductivity, and a base metal having good weldability is integrally provided on a part of the base. The lens optical system optically coupled to the LD element is configured to be welded to the welding base metal by a lens holder made of a material having substantially the same thermal expansion coefficient as that of the welding base metal, so that the heat generated by the LD element can be quickly transmitted through the base. It is also possible to dissipate the heat, and at the same time, eliminate the optical axis shift between the LD element and the lens optical system due to the thermal expansion change of the base and lens holder due to the heat generated by the LD element, and improve the reliability with respect to the temperature cycle. It can be improved. This makes it possible to configure the semiconductor laser module of the present invention as an excitation semiconductor laser module for an EDFA requiring high light output.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view of an embodiment of a semiconductor laser module of the present invention.

FIG. 2 is a plan view showing an assembled state of the semiconductor laser module of FIG. 1;

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a perspective view of a first step of an assembling step showing the method for manufacturing a semiconductor laser module of the present invention.

FIG. 5 is a perspective view of a second step of the assembling step showing the method for manufacturing a semiconductor laser module of the present invention.

FIG. 6 is a perspective view of a third step of the assembling step showing the method for manufacturing a semiconductor laser module of the present invention.

FIG. 7 is a diagram showing a comparison between thermal expansion coefficients of various parts of the present invention and a conventional LD / lens module.

FIG. 8 is a sectional configuration diagram of a conventional semiconductor laser module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser module 100 LD / lens module 110 LD element 111 Heat sink 120 Lens optical system 121 Lens holder 122 Lens barrel 123 Lens fixing bracket 130 Base 132 Welding base metal 140 Circuit board 200 Module case 210 Cooler (Peltier element) 220 Second Lens optical system 230 optical fiber 240 connector terminal

Claims (10)

[Claims] 1. A semiconductor laser module having a semiconductor laser element and a lens optical system mounted on a base, wherein the base is made of a material having a high thermal conductivity.
A weld base metal having good weldability is integrally provided on a part thereof, and the lens optical system is welded to the weld base metal by a lens holder made of a material having substantially the same thermal expansion coefficient as the weld base metal. A semiconductor laser module characterized by the above-mentioned. 2. The base is made of copper tungsten (CuW).
The semiconductor laser module according to claim 1, wherein: 3. The semiconductor laser module according to claim 1, wherein said base metal for welding is made of a material having a thermal expansion coefficient close to a thermal expansion coefficient of said base. 4. The lens holder includes a lens barrel holding a lens and a lens fixing bracket holding the lens barrel, and at least the lens fixing bracket is formed of the same material as the base metal for welding. The semiconductor laser module according to claim 1, wherein: 5. The semiconductor laser module according to claim 4, wherein the welding base metal and the lens fixing metal are stainless steel (SUS430). 6. The semiconductor laser module according to claim 1, wherein said welding is laser welding. 7. A semiconductor laser module according to claim 1, which is built in a module case having a second lens optical system optically coupled to an optical fiber,
A semiconductor laser module, wherein a lens optical system of the semiconductor laser module and a second lens optical system provided in the module case are optically coupled. 8. A step of integrally providing a base metal which can be laser-welded to a part of a base made of a material having high thermal conductivity, and a step of mounting a semiconductor laser element to another part of the base. Causing the semiconductor laser to emit light and laser welding a lens holder of the lens optical system onto the welding base metal while aligning an optical axis of the lens optical system with laser light emitted from the semiconductor laser element. A method of manufacturing a semiconductor laser module, wherein the lens holder and the welding base metal are made of materials having substantially equal thermal expansion coefficients. 9. The lens optical system includes a lens barrel for holding a lens, and a lens fixing bracket for holding the lens barrel. After the lens fixing bracket is laser-welded, the lens optical system is mounted on the lens fixing bracket. The method for manufacturing a semiconductor laser module according to claim 8, further comprising a step of laser welding said lens barrel. 10. The method for manufacturing a semiconductor laser module according to claim 8, wherein said laser welding is YAG welding.