JP2003243758A - Semiconductor laser module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve manufacturing efficiency of a semiconductor laser module and quality of laser light outputted from the module. <P>SOLUTION: The semiconductor laser module is constituted by fixing a semiconductor laser 6 on a subcarrier 4 fixed to the upper surface of a Peltier element 3 provided in a package 1, and emits the light 5 emitted from the laser 6 to an optical fiber 13 attached to the outside of a window 11 made through one side wall 1b of the package 1 through a lens 7 and an isolator 9 provided in the package 1 and the window 11. The isolator 9 incorporated in the package 1 is removed from an upper surface of the subcarrier 4 mounted with the semiconductor laser 6 to another location in the package 1 satisfying the optical axis of the laser 6 and thermally coupled with the Peltier element 3. <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 module, and more particularly to an isolator for suppressing light emitted from the semiconductor laser from entering the semiconductor laser again due to interface reflection or the like, and an isolator. The present invention relates to a semiconductor laser module incorporating a Peltier element for controlling the temperature at a constant value.

[0002]

2. Description of the Related Art As a semiconductor laser module for outputting laser light used for an optical signal in an optical communication system, light (laser light) output from a semiconductor laser is reflected by an end face of an optical fiber connected to this module. As a result, a semiconductor laser module incorporating an isolator that suppresses re-incident light to the semiconductor laser and a Peltier element that controls the temperature of the semiconductor laser to a constant value has been put into practical use.

This semiconductor laser module is, for example,
It is configured as shown in FIGS. 9 and 10. FIG. 9 is a plan view showing only the semiconductor laser module package horizontally cut, and FIG. 10 is a cross-sectional view of the semiconductor laser module package shown in FIG. 9 taken along the line AA ′.

A heat radiating plate 2 is attached to the upper surface of a bottom wall 1a in a package 1 formed in a box shape from a metal material in which an inert gas such as nitrogen is sealed, and a plate-like shape is provided on the upper surface of the heat radiating plate 2. The Peltier device 3 is attached. The subcarrier 4 is attached to the upper surface of the plate-shaped Peltier element 3. As shown in FIG. 10, the upper surface of the subcarrier 4 is formed of one upper step portion 4a and two lower step portions 4b and 4c. A semiconductor laser 6 that emits light (laser light) 5 is fixed on the upper portion 4a of the subcarrier 4,
A lens holder 8 for holding the lens 7 and an isolator holder 10 for internally holding an isolator 9 composed of a Faraday rotator 9a and a magnet 9b shown in FIG. 11 are fixed on one lower step portion 4b.

The subcarrier 4 is formed of, for example, a metal plate having good heat conduction characteristics, and has a function of supporting the above-mentioned components such as the semiconductor laser 6, the lens holder 8 and the isolator holder 10. The reason why the step is provided on the upper surface of the subcarrier 4 is to make the optical axis of the light (laser light) 5 emitted from the semiconductor laser 6 coincide with the optical axes of the lens 7 and the isolator 9.

Light (laser light) 5 emitted from the semiconductor laser 6 propagates in the air while propagating to reach the lens 7. The wavefront of this light (laser light) 5 is converted into a convergent beam by a lens 7 (Kono, "Fundamental and application of optical coupling system for optical devices" (2nd edition), Hyundai Engineering Co., 1998.
Year). The light (laser light) 5 whose wavefront is converted into a convergent beam by the lens 7 passes through the isolator 9 and the window 11 formed in one side wall 1b of the package 1 and is attached to the outside of the window 11. The light is condensed in the fixed member 12.
A ferrule 14 holding one end of the optical fiber 13 is inserted and fixed in the fixing member 12. A transparent member for sealing the inside of the package 1 is inserted into the window 11.

Therefore, the light (laser light) 5 emitted from the semiconductor laser 6 is emitted to the outside through the optical fiber 13. Since the end surface 13 a of the optical fiber 13 is inclined with respect to the optical axis of the light (laser light) 5, the end surface 13 a
The amount of the light reflected by a returning to the semiconductor laser 6 side is suppressed.

Further, the other lower stage portion 4 of the subcarrier 4
In c, light emitted from the semiconductor laser 6 (laser light)
A monitor photodiode 15 is provided for detecting the emission intensity of the light.

Further, a thermistor 16 for detecting the temperature of the semiconductor laser 6 is attached to the upper step portion 4a of the subcarrier 4 formed of a metal plate having good heat conduction characteristics. The Peltier element 3 is energized and controlled so that the temperature of the semiconductor laser 6 detected by the thermistor 16 maintains a desired temperature, and the heat generated by the semiconductor laser 6 is absorbed through the subcarrier 4 to radiate heat. Bottom wall 1 through plate 2
Dissipate heat to the outside of a. The semiconductor laser 6 is usually fixed to the subcarrier 4 via a heat sink having a high thermal conductivity, but it is omitted here for the sake of simplicity.

Thus, by controlling the temperature of the semiconductor laser 6 to a constant value by using the Peltier device 3, the wavelength of the light (laser light) 5 emitted from the semiconductor laser 6 is controlled to a constant value with high accuracy. it can.

Further, as shown in FIG. 9, the package 1
A plurality of terminals 17 for inputting and outputting various signals for driving the semiconductor laser module and controlling its operation are attached to the outside of the.

Next, the structure and function of the isolator 9 incorporated in this semiconductor laser module will be described.
Note that, for simplicity of explanation, in FIG. 11, the isolator 9 is described as being composed of the Faraday rotation element 9a and the magnet 9b, but in reality, a polarizer and an analyzer are also incorporated.

A cylindrical isolator 9 including a Faraday rotator 9a and a magnet 9b arranged on the outer periphery of the Faraday rotator 9a is an end face 13 of an optical fiber 13.
It has a function of suppressing the light 5 reflected from a or the like from entering (combining) again with the semiconductor laser 6. That is, the TE-polarized light 5 emitted from the semiconductor laser 6 is transmitted through the optical fiber 1
When passing through the Faraday rotation element 9a, which is a component of the isolator 9, in the direction of 3
Degree rotation (Kono, Kito, "Basics of optical waveguide analysis", Hyundai Engineering Co., 1998).

Further, when the reflected return light from the end face 13a of the optical fiber 13 or the connector attached to the optical fiber 13 returns to the Faraday rotator 9a in the direction of the semiconductor laser 6, the polarization direction thereof further rotates by 45 degrees. To do. As a result, when the reflected return light passes through the Faraday rotator 9a toward the semiconductor laser 6, it becomes TM polarized light, and is extinguished by the polarizer that is a component of the isolator 9.

Therefore, it is very important to control the rotation angle in the polarization direction of the light passing through the Faraday rotator 9a. If the rotation angle changes, a large amount of light returning from the Faraday rotation element 9a toward the semiconductor laser 6 is generated, and the light intensity of the light (laser light) 5 output from the semiconductor laser 6 changes.

The direction of polarization of the light passing through the Faraday rotator 9a easily fluctuates according to changes in ambient temperature. Therefore, in order to control the temperature of the isolator 9 at a constant level, the isolator holder 10 holding the isolator 9 therein is mounted on the subcarrier 4, and the temperature of the isolator 9 is changed in common with the semiconductor laser 6 described above. Peltier element 3 via subcarrier 4
Is controlled to a constant temperature.

Next, a method of fixing the isolator 9 to the lower stage portion 4b of the subcarrier 4 will be described. It is difficult to directly apply YAG laser welding to the magnet 9b which is a component of the isolator 9. Therefore, as shown in FIG. 11, the entire cylindrical isolator 9 composed of the Faraday rotator 9a and the magnet 9b is covered with an isolator holder 10 which is made of metal and formed into a tubular shape, and this isolator holder 10 is subjected to YAG laser welding. It is fixed to the lower part 4b of the subcarrier 4.

When the isolator 9 is fixed on the lower step portion 4b of the subcarrier 4 by soldering, the isolator 9
The periphery of the magnet 9b, which is a component of the above, may be metal-plated, and the metal plating and the lower step portion 4a of the subcarrier 4 may be fixed by soldering. Therefore, in this case, the isolator holder 10 may not be used.

A semiconductor laser module having the above-mentioned basic structure is also disclosed in Japanese Patent No. 2716122.

[0020]

However, as shown in FIG.
The semiconductor laser module configured as shown in FIG. 10 still has the following problems to be solved.

That is, in this semiconductor laser module, the lens holder 8 for supporting the lens 7 and the isolator holder 10 for internally holding the isolator 9 are provided on the upper surface of the subcarrier 4 fixed on the Peltier device 3, and one lower step portion thereof. It is fixed on a.

Here, the inner width indicated by the area of the bottom wall 1a of the package 1 is as small as about 10 mm × 20 mm. Therefore, the surface area of the Peltier element 3 connected to the bottom wall 1a via the heat dissipation plate 2 is also small. That is, the subcarrier 4 fixed on the Peltier device 3 having a small surface area.
Despite its small area, components such as the semiconductor laser 6, the lens holder 8 supporting the lens 7, and the isolator holder 10 holding the isolator 9 therein are arranged and fixed on the upper surface of the subcarrier 4.

Although the length of the semiconductor laser 6 itself in the optical axis direction is as small as several hundred μm, the length of the lens 7 and the lens holder 8 is as large as about 3 mm. Further, in the isolator 9, as shown in FIG. 11, the diameter of the Faraday rotation element 9a is about 2 to 3 mm, the thickness of the magnet 9b is about 1 mm, and the thickness of the isolator holder 10 is 0.5 m.
Since it is about m, the total diameter including the isolator holder 10 is about 3.5 to 4.5 mm. However, since the length of the magnet 9b is as long as about 3 mm or more, the length of the isolator holder 10 in the optical axis direction is 4 to 5 mm.
It becomes as long as mm.

As a result, the components such as the lens holder 8 for supporting the lens 7 and the isolator holder 10 for holding the isolator 9 therein are arranged and fixed on the upper surface of the subcarrier 4, and the semiconductor laser module shown in FIGS. In the manufacturing process of this semiconductor laser module, the work of mounting (mounting) components such as the lens holder 8 and the isolator holder 10 on the upper surface of the subcarrier 4 becomes very complicated, and the manufacturing work efficiency decreases. Furthermore, the work becomes very complicated, and there is a concern that the manufacturing yield may be reduced.

Further, as described above, the semiconductor laser 6
In order to make the optical axis of the light 5 emitted from the optical axis coincide with the optical axes of the lens 7 and the isolator 9, a step is provided on the upper surface of this subcarrier 4. The required step difference between the upper step portion 4a and the lower step portion 4b provided on the upper surface of the subcarrier 4 is
Considering that the outer diameter of the semiconductor laser 6 is very small, it has a value corresponding to the radius of the isolator holder 10. The radius of this isolator holder 10 is shown in FIG.
Since the thickness is about 1.7 to 2.3 mm, the upper portion 4a of the subcarrier 4 to which the semiconductor laser 6 is attached must have a thickness of at least 3.5 mm or more.

As the thickness of the subcarrier 4 increases, the accuracy of temperature control of the semiconductor laser 6 using the Peltier device 3 decreases. When the temperature of the semiconductor laser 6 changes, the wavelength of the light (laser light) 5 emitted from the semiconductor laser 6 may change. Further, the size of the entire semiconductor laser module is increased.

The present invention has been made in view of the above circumstances, and the manufacturing efficiency can be greatly improved and the manufacturing yield can be improved only by changing the arrangement and thermal coupling of the components incorporated in the package. It is an object of the present invention to provide a semiconductor laser module that has improved characteristics and that can suppress fluctuations in wavelength and light intensity of output laser light and that have high characteristics.

[0028]

According to the present invention, a semiconductor laser is fixed on a subcarrier fixed on the upper surface of a Peltier device provided inside a package, and light emitted from this semiconductor laser is introduced into the package. The present invention is applied to a semiconductor laser module that emits light to an optical fiber mounted on the outside of a window through a window formed in a side wall of a package through a lens and an isolator provided.

In order to solve the above problems, in the semiconductor laser module of the present invention, the isolator is fixed to the side wall in the package at the position where the window is formed, and the isolator is thermally connected to the Peltier element. Is bound to.

In the semiconductor laser module configured as described above, the isolator is not on the subcarrier on which the semiconductor laser emitting the laser light is fixed,
The side wall in the package is fixed at the position where the window is punched. The work of fixing the isolator to the side wall is remarkably improved in workability as compared with the work of fixing the isolator on the subcarrier, which requires mounting a large number of components. Therefore, the overall manufacturing efficiency of the semiconductor laser module can be significantly improved.

Further, since the isolator having a large outer diameter is not mounted on the subcarrier, even if the thickness of the subcarrier is set thin, the optical axis of the semiconductor laser fixed on the subcarrier and the optical axis of the isolator are fixed. It is possible to match the axis. Therefore, by setting the subcarrier on which the semiconductor laser is mounted thin, the entire semiconductor laser module can be downsized.

The isolator is also thermally coupled to the Peltier element. That is, by moving the installation location of the isolator from above the subcarrier to the side wall of the package, the isolator becomes less susceptible to temperature control by the Peltier element via the subcarrier. Therefore, separately, the isolator and the Peltier element are thermally joined to each other to enable temperature control by the Peltier element, and the isolator temperature is controlled to be constant.

As a result, the polarization direction of the passing light in the Faraday rotator in the isolator becomes constant,
It is possible to sufficiently exert the function of an isolator that suppresses the light that returns to the semiconductor laser. That is, the light intensity of the output laser light can be stabilized.

Another aspect of the present invention is the semiconductor laser module described above, wherein the isolator is mounted on a pedestal attached to the bottom wall of the package so that the isolator is located at the position where the window is formed in the side wall of the package. It is fixed and thermally coupled to the Peltier element.

Also in the semiconductor laser module having such a structure, since the isolator is not mounted on the subcarrier, it is possible to obtain substantially the same effect as the above-mentioned invention. In the above-mentioned semiconductor laser module of each invention, the isolator is thermally coupled to the Peltier device via the heat conductor.

In still another invention, in the semiconductor laser module of each invention described above, the vicinity of the isolator and the vicinity of the Peltier element are physically contacted so that the isolator is thermally coupled to the Peltier element. There is.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a plan view showing a schematic configuration of a semiconductor laser module according to a first embodiment of the present invention, and FIG. 2 shows the semiconductor laser module of FIG.
It is sectional drawing at the time of cutting along a line. The same parts as those of the conventional semiconductor laser module shown in FIGS. 9 and 10 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted.

In the semiconductor laser module of the first embodiment, the heat dissipation plate 2 is attached to the upper surface of the bottom wall 1a in the package 1, and the plate-shaped Peltier element 3 is attached to the upper surface of the heat dissipation plate 2. This plate-shaped Peltier element 3
A subcarrier 4 formed of a metal plate having good heat conduction characteristics is attached to the upper surface of the subcarrier 4. As shown in FIG. 2, the upper surface of the subcarrier 4 is formed of one upper step portion 4a and two lower step portions 4b and 4c. A semiconductor laser 6 that emits light (laser light) 5 is fixed on the upper step 4a of the subcarrier 4, and a lens holder 8 that supports a lens 7 is fixed on one lower step 4b.

A window 11 is formed at a position on one side wall 1b of the package 1 where the light (laser light) 5 emitted from the semiconductor laser 6 is irradiated, and at a position where the window 11 is formed on the inner surface of the side wall 1b. An isolator holder 10 holding an isolator 9 composed of a Faraday rotator 9a and a magnet 9b shown in FIG. 11 is fixed so as to cover the window 11.

Then, the lower stage portion 4 of the isolator 9 and the subcarrier 4 held inside the isolator holder 10 are provided.
The upper surface of b is connected by a heat conductor 21. The heat conductor 21 is formed of a metal plate, a metal wire, a metal ribbon, or the like having good heat conduction characteristics.

The light (laser light) 5 emitted from the semiconductor laser 6 has its wavefront converted into a convergent beam by the lens 7, and is attached to one side wall 1b of the package 1 by the isolator 9 and the side wall 1b fixed by the isolator holder 10. The light passes through the perforated window 11 and is condensed in the fixing member 12 attached to the outside of the window 11. A ferrule 14 holding one end of the optical fiber 13 is inserted and fixed in the fixing member 12. A transparent member for sealing the inside of the package 1 is inserted into the window 11.

Therefore, the light (laser light) 5 emitted from the semiconductor laser 6 is emitted to the outside through the optical fiber 13. Since the end face 13a of the optical fiber 13 is inclined with respect to the optical axis of the light 5, the amount of light reflected by this end face 13a returning to the semiconductor laser 6 side is suppressed.

Further, the other lower stage portion 4 of the subcarrier 4
In c, light emitted from the semiconductor laser 6 (laser light)
A monitor photodiode 15 is provided for detecting the emission intensity of the light.

In addition, in the upper part 4a of the subcarrier 4,
Thermistor 16 for detecting the temperature of the semiconductor laser 5
Is installed. In order that the temperature of the semiconductor laser 6 detected by the thermistor 16 maintains a desired temperature,
The Peltier element 3 is energized and controlled to absorb the heat generated by the semiconductor laser 6 and radiate it to the outside of the bottom wall 1a via the heat dissipation plate 2. Further, as shown in FIG. 1, a plurality of terminals 17 to which signals for driving the semiconductor laser module and controlling its operation are input and output are attached to the outside of the package 1.

In the semiconductor laser module of the first embodiment configured as described above, as shown in FIGS. 1 and 2, the isolator 9 including the Faraday rotation element 9a and the magnet 9b shown in FIG. 11 is held inside. The isolator holder 10 is fixed not on the subcarrier 4 on which the semiconductor laser 6 for emitting the light (laser light) 5 is attached, but on the side wall 1b having the window 11 of the package 1 formed therein. Then, only the lens holder 8 that supports the lens 7 is attached to the lower stage portion 4b of the subcarrier 4.

The work of fixing the isolator holder 10 holding the isolator 9 inside to the side wall 1b of the package 1 is much easier than the work of fixing a large number of parts on the subcarrier 4. Therefore, the overall manufacturing efficiency of the semiconductor laser module can be significantly improved. In addition, the degree of freedom in manufacturing in the order of assembling each component can be improved.

Further, the isolator 9 having a large outer diameter dimension
Since the isolator holder 10 for holding the inside of the subcarrier is not mounted on the lower stage 4b of the subcarrier 4, the optical axis of the light 5 emitted from the semiconductor laser 6 is made to coincide with the optical axes of the lens 7 and the isolator 9. The step difference between the upper step portion 4a and the lower step portion 4b can be reduced.

By making the step small, it is possible to set the total thickness of the subcarrier 4 to be thin. As a result, the distance between the Peltier device 3 and the semiconductor laser 6 is reduced, and the temperature control accuracy of the semiconductor laser 6 by the Peltier device 3 can be greatly improved. Therefore, the wavelength stability of the light (laser light) 5 output from the semiconductor laser 6 can be significantly improved.

Roughly, the semiconductor laser 6 of the subcarrier 4
By setting the thickness of the upper portion 4a attached to the semiconductor laser module to be thin, the entire semiconductor laser module can be downsized.

Further, the lower stage portion 4 of the isolator 9 and the subcarrier 4 held inside the isolator holder 10 are provided.
The upper surface of b is connected by a heat conductor 21. As described above, since the subcarrier 4 is formed of a metal plate having good heat conduction characteristics, the isolator 9 is thermally coupled to the Peltier element 3. As a result, the isolator 9 is controlled to a constant temperature by the Peltier device 3 as in the semiconductor laser 6 described above.

Therefore, the polarization direction of the passing light in the Faraday rotator 9a of the isolator 9 becomes constant, and the original function of the isolator 9 that suppresses the returning light incident on the semiconductor laser 6 can be sufficiently exhibited. That is, the light intensity of the light (laser light) 5 output from the semiconductor laser 6 can be stabilized.

As described above, in the semiconductor laser module of the first embodiment, the manufacturing efficiency is improved, which is represented by the degree of freedom in assembling the semiconductor laser module, and the wavelength stability and the optical stability of the output light (laser light) 5 are improved. Both improvement of strength stability can be ensured.

In the embodiment shown in FIGS. 1 and 2,
Although the other end of the heat conductor 21 whose one end is connected to the isolator 9 is fixed to the upper surface of the subcarrier 4, it is possible to directly connect it to the end surface of the Peltier element 3. Further, one end of the heat conductor 21 is connected to the Faraday rotation element 9a of the isolator 9.
It is also possible to directly connect to or to the isolator holder 10.

(Second Embodiment) FIG. 3 is a sectional view showing the schematic arrangement of a semiconductor laser module according to the second embodiment of the present invention. The same parts as those of the semiconductor laser module of the first embodiment shown in FIG. 2 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted. In addition,
The plan view is omitted.

In the semiconductor laser module of the second embodiment, the light (laser light) 5 emitted from the semiconductor laser 6 mounted on the upper step portion 4a of the subcarrier 4 on one side wall 1b of the package 1 is irradiated. The window 11 is formed at the position where the window 1 is formed on the inner surface of the side wall 1b.
A recess 18 having a circular cross section is formed at a position including 1. The isolator 9 including the Faraday rotation element 9a and the magnet 9b shown in FIG.
The tip portion of the isolator holder 10 that holds the inside is inserted and fixed.

Further, the isolator 9 held inside the isolator holder 10 inserted and fixed in the recess 18 and the upper surface of the lower step portion 4b of the subcarrier 4 are connected by the heat conductor 21.

In the semiconductor laser module of the second embodiment having such a structure, the isolator holder 10 for holding the isolator 9 therein is not mounted on the subcarrier 4, so the semiconductor of the first embodiment described above. Similar to the laser module, the manufacturing efficiency of the semiconductor laser module can be improved and the degree of freedom in assembling each component can be secured.

Further, in the semiconductor laser module according to the second embodiment, the side wall 1a in the package 1 is previously prepared.
Since the isolator holder 10 holding the isolator 9 therein is only inserted and fixed in the recess 18 formed in the above, the positioning work at the time of mounting the isolator holder 10 is greatly simplified. Therefore, the manufacturing efficiency can be further improved.

Further, similarly to the first embodiment shown in FIGS. 1 and 2, the isolator 9 held inside the isolator holder 10 and the upper surface of the lower step portion 4b of the subcarrier 4 are connected by the heat conductor 21. Therefore, the Peltier device 3 controls the isolator 9 to a constant temperature. Therefore, the return light that passes through the isolator 9 and enters the semiconductor laser 6 is suppressed, and the light intensity of the light (laser light) 5 output from the semiconductor laser 6 can be stabilized.

In the semiconductor laser module of the second embodiment shown in FIG. 3, the isolator 9 is provided in the recess 18.
Although the tip portion of the isolator holder 10 holding therein is fixed, the tip portion of the isolator 9 may be directly inserted and fixed in the recess 18.

(Third Embodiment) FIG. 4 is a sectional view showing the schematic arrangement of a semiconductor laser module according to the third embodiment of the present invention. The same parts as those of the semiconductor laser module according to the second embodiment shown in FIG. 3 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted. In addition,
The plan view is omitted.

In the semiconductor laser module of the third embodiment, the light (laser light) 5 emitted from the semiconductor laser 6 mounted on the upper step portion 4a of the subcarrier 4 on one side wall 1b of the package 1 is emitted. A window 11 is formed at a position to be irradiated, and a recess 18 having a circular cross section is formed at a position including the window 11 on the inner surface of the side wall 1b. Then, the tip of a wall-side holder 19 formed in advance in a cylindrical shape is fitted and fixed in the recess 18. A cylindrical isolator 9 including a Faraday rotator 9a and a magnet 9b shown in FIG. 11 is inserted and fixed in the wall-side holder 19.

Further, the isolator 9 held inside the isolator holder 10 inserted and fixed in the wall side holder 19 and the upper surface of the lower step portion 4b of the subcarrier 4 are connected by a heat conductor 21.

Also in the semiconductor laser module of the third embodiment having such a structure, the package 1 is previously prepared in the same manner as the semiconductor laser module of the second embodiment described above.
Since only the isolator 9 is attached to the inside of the wall side holder 19 which is attached to the side wall 1a inside, the positioning work when the isolator 9 is attached is greatly simplified. Therefore, the manufacturing efficiency can be further improved.

Further, the lower stage portion 4 of the isolator 9 and the subcarrier 4 held inside the isolator holder 10 are provided.
Since the upper surface of b is connected by the heat conductor 21, the isolator 9 is controlled to a constant temperature by the Peltier element 3. Therefore, the semiconductor laser 6 passes through the isolator 9 and
The return light incident on is suppressed, and the light intensity of the light (laser light) 5 output from the semiconductor laser 6 can be stabilized.

In the semiconductor laser module of the third embodiment shown in FIG. 4, the isolator 9 is directly inserted and fixed in the wall side holder 19, but the isolator 9 is housed in the isolator holder 10 and the wall side It may be inserted and fixed in the holder 19.

When the axial length of the wall-side holder 19 becomes long, the tip of the wall-side holder 19 comes into contact with the subcarrier 4. It is necessary to lower the position of the lower step portion 4b and position the wall-side holder 19 above the lower step portion 4b of the subcarrier 4.

In this case, in the manufacturing process, in the work of mounting various parts on the sub-carrier 4, due to the existence of the wall side holder 19, the parts are assembled as much as the above-described first and second embodiments. The degree of freedom and manufacturing efficiency cannot be expected.

However, even in that case, since the wall-side holder 19 is fixed to the side wall 1b of the package 1, it is not necessary to fix the wall-side holder 19 on the subcarrier 4, and the lens holder 8 on the subcarrier 4 is not necessary. It becomes easy to fix parts such as.

As a result, as compared with the conventional semiconductor laser module shown in FIGS. 9 and 10, the degree of freedom in assembling the module is significantly improved. As in the case of the first embodiment shown in FIG. 2, even if a part of the wall-side holder 19 is fixed so as not to be embedded in the recess 18 formed in the side wall 1b of the package 1, the above-described technical effect can be obtained. It goes without saying that it can be fully demonstrated.

(Fourth Embodiment) FIG. 5 is a sectional view showing the schematic arrangement of a semiconductor laser module according to the fourth embodiment of the present invention. The same parts as those of the semiconductor laser module of the first embodiment shown in FIG. 2 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted. In addition,
The plan view is omitted.

In the semiconductor laser module of the fourth embodiment, the optical axis direction of the isolator holder 10 which internally holds the isolator 9 whose one end is fixed at a position including the opening position of the window 11 on the side wall 1b of the package 1. Has a long length, and its tip portion is the lower step portion 4b of the subcarrier 4.
Touches the upper surface of. In this case, the isolator holder 1
Since the outer peripheral surface of 0 can be regarded as being thermally coupled to the upper surface of the lower step portion 4b of the subcarrier 4, the isolator 9
The heat conductor 21 for thermally connecting the lower part 4b of the subcarrier 4 and the subcarrier 4 is not provided.

Also in the semiconductor laser module of the fourth embodiment having such a configuration, the isolator holder 10 which elbows the isolator 9 inside is attached not to the subcarrier 4 but to the side wall 1b of the package 1. Therefore, the manufacturing efficiency can be improved similarly to the semiconductor laser module of the first embodiment shown in FIG.

Further, since the isolator 9 is thermally coupled to the Peltier device 3 via the subcarrier 4, it is output from the semiconductor laser 6 as in the semiconductor laser module of each of the above-described embodiments. The light intensity of the light (laser light) 5 can be stabilized.

(Fifth Embodiment) FIG. 6 is a sectional view showing the schematic arrangement of a semiconductor laser module according to the fifth embodiment of the present invention. The same parts as those of the semiconductor laser module of the first embodiment shown in FIG. 2 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted. In addition,
The plan view is omitted.

In the semiconductor laser module of the fifth embodiment, the isolator holder 10 holding the isolator 9 therein is not fixed to the side wall 1b of the package 1, but is fixed to the bottom wall 1a of the package 1. It is fixed to the upper surface of the pedestal 20. The height of the pedestal 20 is set so that the optical axis of the isolator 9 matches the optical axis of the light (laser light) 5 emitted from the semiconductor laser 6 fixed on the subcarrier 4.

Further, the isolator 9 held inside the isolator holder 10 fixed on the pedestal 20.
And the upper surface of the lower step portion 4b of the subcarrier 4 are the heat conductor 21.
Connected by.

Also in the semiconductor laser module of the fifth embodiment having such a configuration, the isolator holder 10 for internally supporting the isolator 9 having a large outer diameter shown in FIG. 11 is not mounted on the subcarrier 4, so that
It is possible to obtain substantially the same technical effects on manufacturing as the first to fourth embodiments described above.

Further, the isolator 9 includes the heat conductor 21.
Also, since it is thermally coupled to the Peltier device 3 via the subcarrier 4, the light (laser light) 5 output from the semiconductor laser 6 is the same as the semiconductor laser module of each of the above-described embodiments. The strength can be stabilized.

If the height of the isolator holder 10 is designed and manufactured in advance so that the optical axis of the isolator 9 coincides with the optical axis of the light (laser light) 5 emitted from the semiconductor laser 6, the pedestal 20 can be manufactured. Is unnecessary. In this case, the isolator holder 10 has both the function of holding the isolator 9 inside and the function of the pedestal 20 that sets the position of the isolator 9.

(Sixth Embodiment) FIG. 7 is a sectional view showing the schematic arrangement of a semiconductor laser module according to the sixth embodiment of the present invention. The same parts as those of the semiconductor laser module according to the fifth embodiment shown in FIG. 6 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted. In addition,
The plan view is omitted.

In the semiconductor laser module according to the sixth embodiment, the isolator holder 10 holding the isolator 9 therein is not located near the side wall 1b of the package 1 but on the upper surface of the lower step portion 4b of the subcarrier 4 in the package. 1 is supported and fixed by a pedestal 20a fixed to the bottom wall 1a.

In this case, since the isolator holder 10 is thermally connected to the Peltier element 3 via the pedestal 20a and the subcarrier 4, the heat conductor 21 that connects the isolator 9 and the subcarrier 4 is provided. Has not been done. The pedestal 20a is made of a metal material having good heat conduction characteristics.

In the semiconductor laser module of the sixth embodiment having such a configuration, since the isolator 9 or the isolator holder 10 is present above the subcarrier 4, during the manufacturing process, on the subcarrier 4,
In the work of mounting various parts, this wall-side holder 1
Due to the presence of 9, the degree of freedom in assembling parts and the improvement in manufacturing efficiency cannot be expected as much as in the above-described first and second embodiments.

However, since it is not necessary to fix the pedestal 20a fixing the isolator 9 or the isolator holder 10 to the sub carrier 4, it is easy to fix the optical components such as the lens 7 on the sub carrier 2. There is. As a result, the degree of freedom when assembling the module is significantly improved as compared with the conventional semiconductor laser module shown in FIGS.

Further, since the isolator 9 is thermally coupled to the Peltier device 3 via the isolator holder 10, the pedestal 20a and the subcarrier 4, the isolator 9 is similar to the semiconductor laser modules of the above-mentioned respective embodiments. ,
The light intensity of the light (laser light) 5 output from the semiconductor laser 6 can be stabilized.

(Seventh Embodiment) FIG. 8 is a sectional view showing the schematic arrangement of a semiconductor laser module according to the seventh embodiment of the present invention. The same parts as those of the semiconductor laser module of the first embodiment shown in FIG. 2 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted. In addition,
The plan view is omitted.

In the semiconductor laser module of the seventh embodiment, the isolator holder 10 holding the isolator 9 inside is fixed to the side wall 1b of the package 1, and the lens holder 8 supporting the lens 7 is attached to the subcarrier 4. It is fixed to the end surface of the lower step portion 4b in the optical axis direction. In this case, the length of the lower step portion 4b of the subcarrier 4 in the optical axis direction is set shorter than the length of a part of the lower step portion 4b of the subcarrier 4 of the first embodiment in FIG. 2 in the optical axis direction.
Naturally, the optical axis of the lens 7 coincides with the optical axis of the light (laser light) 5 output from the semiconductor laser 6.

Further, the isolator 9 held inside the isolator holder 10 fixed to the side wall 1b of the package 1 and the upper surface of the subcarrier 4 are connected by the heat conductor 21.

Also in the semiconductor laser module of the seventh embodiment having such a configuration, the isolator holder 10 holding the isolator 9 inside is fixed to the side wall 1b of the package 1, so that it is almost the same as each of the above-mentioned embodiments. The same technical effect on manufacturing can be obtained.

Further, in the seventh embodiment, since the lens holder 8 supporting the lens 7 is not mounted on the lower step portion 4b of the subcarrier 4, the thickness of the lower step portion 4b of the subcarrier 4 can be set thinner. Alternatively, the lower part 4b can be removed. As a result, the thickness of the subcarrier 4 as a whole can be set thinner, so that the temperature control accuracy for the semiconductor laser 6 by the Peltier device 3 can be further improved.

The concept of this embodiment in which the lens holder 8 is not mounted on the lower step portion 4b of the carrier 4 can be applied not only to the first embodiment but also to each of the second to sixth embodiments. Needless to say.

Further, the isolator 9 includes the heat conductor 21.
Since it is thermally coupled to the Peltier element 3 via the light, the light (laser light) output from the semiconductor laser 6 is similar to the semiconductor laser modules of the above-described embodiments.
The light intensity of 5 and the oscillation wavelength can be stabilized.

The present invention is not limited to the above embodiments. Since the purpose of the present invention is to thermally couple the isolator 9 and the Peltier element 3,
Needless to say, the Peltier device 3 may contact the heat conductor 21 instead of the subcarrier 4, or the isolator holder 10 or the wall-side holder 19 may replace the isolator 9.

In the above description, "two substances are thermally coupled" may mean "two substances are in physical contact", but "two substances are in physical contact" may be "not in physical contact". There is heat transfer in the two substances via a medium (heat conductor) capable of transferring heat such as a heat conductive paste or a metal material. "

Furthermore, a plurality of heat conductors 21 may be used in each embodiment. Further, in order to reduce the thermal coupling between the wall-side holder 19 and the package 1 and to strengthen the thermal coupling between the Peltier element 3 and the isolator 9, the isolator holder 10 and the wall-side holder 19 have a cylindrical shape. If the contact area with the package 1 is reduced and the contact area with the subcarrier 4 or the Peltier element 3 is increased by using a plate shape instead of the plate shape, the temperature control accuracy of the semiconductor laser 6 of the present invention can be improved. Can be increased.

Further, when the isolator holder 10 or the wall side holder 19 is fixed to the side wall 1b of the package 1,
When fixing the pedestal 20, 20a to the bottom wall 1a of the package 1, by providing a notch on the surface of each of these parts 10, 19, 20, 20a facing the side wall 1b and the bottom wall 1b of the package 1. It is possible to devise so that the contact area between the package 1 and these components is as small as possible. Also, each of these parts 10, 1
By interposing a member (washer) having a small heat conduction between the contact surfaces of 9, 20, 20a and the package 1, it is possible to reduce the influence on the isolator 9 even if the temperature of the package 1 changes.

Further, a lens holder 8 for supporting the lens 7
Can be fixed to the end surface of the subcarrier 4.

Further, although the optical coupling system using one lens 7 as the lens system has been described, it goes without saying that the present invention can be applied to the case where two or more lenses are used. Further, as the optical fiber 13 for guiding the light (laser light) 5 to the outside, a semiconductor laser module using various optical fibers such as a multimode optical fiber as well as a single mode optical fiber can be applied.

Further, the principle of the present invention does not depend on the oscillation wavelength of the semiconductor laser 6 used. Therefore, as long as the isolator 9 is built in the module, it is needless to say that it can be applied to a semiconductor laser module using the semiconductor laser 6 that oscillates in a wavelength of 0.5 μm band to 2 μm band or any other wavelength.

[0101]

As described above, in the semiconductor laser module of the present invention, the isolator incorporated in the package is removed from the upper surface of the subcarrier to which the semiconductor laser is fixed, so that the optical axis of the semiconductor laser is satisfied. It is moved to another position inside. Further, the isolator is thermally coupled to the Peltier device.

Therefore, the manufacturing efficiency can be significantly improved and the manufacturing yield can be improved only by changing the arrangement of the isolator. Further, even if the ambient temperature of the semiconductor laser module fluctuates, the output laser light can be changed. It is possible to suppress fluctuations in wavelength and fluctuations in light intensity and to exhibit high characteristics.

[Brief description of drawings]

FIG. 1 is a plan view showing a schematic configuration of a semiconductor laser module according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of the semiconductor laser module according to the first embodiment.

FIG. 3 is a sectional view showing a schematic configuration of a semiconductor laser module according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a schematic configuration of a semiconductor laser module according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing a schematic configuration of a semiconductor laser module according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a schematic configuration of a semiconductor laser module according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing a schematic configuration of a semiconductor laser module according to a sixth embodiment of the present invention.

FIG. 8 is a plan view showing a schematic configuration of a semiconductor laser module according to a seventh embodiment of the present invention.

FIG. 9 is a plan view showing a schematic configuration of a conventional semiconductor laser module.

FIG. 10 is a sectional view showing a schematic configuration of the conventional semiconductor laser module.

FIG. 11 is a perspective view of an isolator incorporated in the conventional semiconductor laser module.

[Explanation of symbols]

1 ... Package 1a ... bottom wall 1b ... Side wall 2 ... Heat sink 3 ... Peltier element 4 ... Subcarrier 4a ... Upper part 4b, 4c ... Lower part 5 ... light 6 ... Semiconductor laser 7 ... Lens 8 ... Lens holder 9 ... Isolator 10 ... Isolator holder 11 ... Windows 12 ... Fixing member 13 ... Optical fiber 15 ... Monitor photodiode 16 ... Thermistor 17 ... Terminal 18 ... Recess 19 ... Wall side holder 20, 20a ... Pedestal 21 ... Thermal conductor

Claims (4)

[Claims] 1. A semiconductor laser is fixed on a subcarrier fixed on the upper surface of a Peltier element provided inside the package, and light emitted from the semiconductor laser is attached to a lens and an isolator provided inside the package. A semiconductor laser module for emitting light to an optical fiber attached to the outside of the package through a window formed in the side wall of the package, wherein the isolator has the window formed in the side wall of the package. A semiconductor laser module fixed in position and thermally coupled to the Peltier device. 2. A semiconductor laser is fixed on a subcarrier fixed on the upper surface of a Peltier device provided inside the package, and light emitted from the semiconductor laser is attached to a lens and an isolator provided inside the package. A semiconductor laser module for emitting light to an optical fiber attached to the outside of the package through a window formed in the side wall of the package, wherein the isolator has the window formed in the side wall of the package. A semiconductor laser module, which is fixed on a pedestal attached to a bottom wall in the package so as to be positioned, and is thermally coupled to the Peltier device. 3. The semiconductor laser module according to claim 1, wherein the isolator is thermally coupled to the Peltier device via a heat conductor. 4. The vicinity of the isolator and the vicinity of the Peltier element are in physical contact with each other so that the isolator is thermally coupled to the Peltier element. 2. The semiconductor laser module according to 2.