JP2002333554A - Semiconductor laser module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser module which has an excellent optical coupling efficiency between a laser diode and an optical fiber regardless the variation in the ambient temperature under which the module is used. SOLUTION: A base 2 is mounted directly on the bottom plate 26 of a package 27 or via a thermo module 25. A laser diode 1 and a lens part 14 which guides a laser beam emitted from the laser diode 1 to an optical fiber 4 for receiving and transmitting the laser beam are mounted on the base 2. The lens part 14 is supported by fixed members 6 and 7 via a sleeve 3 and a lens holder 24. The base 2 is formed of a laser diode mounting member 8 on which the laser diode 1 is mounted and a fixed member mounting member 5 on which the fixed members 6 and 7 are mounted. The wall part 15 of a deformation prevention means is extendedly mounted in the longitudinal direction of the light beam on the fixed member mounting member 5 of the base 2 at least on both sides of the optical coupling region of the laser diode 1 and the lens part 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module used in the field of optical communication.

[0002]

BACKGROUND ART In recent years, semiconductor lasers (laser diodes)
2. Description of the Related Art is widely used as a signal light source or an excitation light source for an optical fiber amplifier in optical communication. When a semiconductor laser is used as a signal light source or an excitation light source in optical communication, it is often used as a semiconductor laser module that is a device in which laser light from a semiconductor laser is optically coupled to an optical fiber.

FIG. 15A shows a configuration example of a conventional semiconductor laser module. The semiconductor laser module shown in FIG. 1 includes a laser diode (semiconductor laser) 1 for emitting laser light, and an optical fiber having a lens portion 14 of a fiber lens opposed to a laser light emitting end face 31 of the laser diode 1. The optical fiber 4 is accommodated in a metal sleeve 3. The optical fiber 4 receives the light emitted from the laser diode 1 via the lens unit 14 and transmits the light. The lens unit 14 is, for example, a wedge-shaped fiber lens.

The sleeve 3 is mounted on the base 2 while being supported by fixing members 6 and 7, and is fixed. The fixing members 6 and 7 support the optical fiber 4 at positions spaced from each other in the longitudinal direction of the optical fiber 4. The laser diode 1 is mounted and fixed on an LD bonding portion 21 on the base 2 via a heat sink 22. Further, a monitor photodiode 9 is mounted on the base 2 via a monitor photodiode fixing component 39, and is configured to monitor the output of the laser diode 1. The base 2 is mounted on a thermo module 25.

The thermo module 25, the base 2, the laser diode 1, the optical fiber 4, and the fixing members 6, 7 are accommodated in a package 27, and the thermo module 25 is mounted on a bottom plate 26 of the package 27.
Is installed. The thermo module 25 includes a base plate 17, a bottom plate 18, and these plates 17, 18.
And a Peltier element 19 tightly attached to the Peltier device.

The fixing members 6 and 7 and the base 2 are
Laser welding is performed at the first laser welded portion 10 by YAG welding (welding using a well-known YAG laser) or the like. Similarly, the fixing members 6, 7 and the sleeve 3 are laser-welded at a second laser-welded portion 11. The second laser welded portion 11 is higher than the first laser welded portion 10 in the Y direction in the drawing (the direction perpendicular to the package bottom plate 26 and the direction perpendicular to the optical axis Z direction of the optical fiber 4). Is formed at a high position.

Since the sleeve 3, the fixing members 6, 7 and the base 2 are fixed by laser welding as described above, the base 2 and the fixing members 6, 7 have low thermal conductivity and are made of metal which is rich in laser weldability. Need to be Further, since the optical fiber 4 is mounted on the base 2 via the fixing members 6 and 7, the material of the base 2 and the fixing members 6 and 7 may be a material having a linear expansion coefficient close to that of the optical fiber 4. preferable.
Therefore, in the conventional semiconductor laser module, the base 2 and the fixing members 6 and 7 are formed of Kovar (trademark) which is an Fe—Ni—Co alloy.

Also, for example, the bottom plate 2 of the package 27
6 is CuW20 of Cu-W alloy (the weight ratio is
% And W is 80%), and the base plate 17 and the bottom plate 18 of the thermo module 25 are both A
It is formed of l ₂ O ₃ .

In the semiconductor laser module, the laser diode 1 and the optical fiber 4 are aligned.
The laser light emitted from the laser diode 1 is received by the optical fiber 4 and transmitted through the optical fiber 4 to be used for a desired application.

Further, in the semiconductor laser module,
When a current flows to drive the laser diode 1, the temperature of the laser diode 1 rises due to heat generation. Since this rise in temperature causes a change in the oscillation wavelength and optical output of the laser diode 1, when the semiconductor laser module is used, the temperature of the laser diode 1 is fixed by a thermistor (not shown) fixed near the laser diode 1. Is measured. Then, the thermo module 25 is operated based on the measured value, and the current flowing through the thermo module 25 is controlled to control the temperature of the laser diode 1 to be constant.

[0011]

However, in the above-described conventional semiconductor laser module, the base 2 may be bent due to various factors. For example, in the example shown in FIG. 15, the base 2 is formed of Kovar, and the base side plate 17 of the thermo module is formed of Al ₂ O ₃ . For this reason, since the linear expansion coefficients of the two greatly differ, the base 2 bends, for example, as shown in FIG. 15B with the operation of the thermomodule 25 when the semiconductor laser module is used. Therefore, the position of the laser diode 1 and the lens unit 14 is shifted from the centering position, and the optical coupling efficiency between the laser diode 1 and the optical fiber 4 is reduced.

Also, for example, even when the semiconductor laser module is left in a high temperature environment of 40 to 50 ° C. without using the semiconductor laser module, the same applies due to the difference in linear expansion coefficient between the base 2 and the base side plate 17 of the thermo module 25. The base 2 is bent. Then, the optical coupling between the laser diode 1 and the lens unit 14 is shifted. Therefore, when the semiconductor laser module is used, there is also a problem that the shift of the optical coupling remains without completely returning to the original state.

In particular, in the conventional semiconductor laser module, the second laser welding portion 11 which is a fixing portion between the sleeve 3 and the fixing members 6 and 7 is composed of the fixing members 6 and 7 and the base 2.
The height is approximately 1600 μm higher in the Y direction in the figure than the first laser welded portion 10 as the laser fixing portion. Therefore, when the base 2 was bent, the sleeve 3 was largely displaced with the first laser welded portion 10 as a fulcrum, and the rate of reduction in the optical coupling efficiency between the laser diode 1 and the optical fiber 4 was large.

As described above, when the optical coupling efficiency between the laser diode 1 and the optical fiber 4 is reduced in accordance with a change in the use environment temperature when the semiconductor laser module is used or left unattended, the light received and transmitted by the optical fiber 4 is reduced. Strength is reduced. Therefore, it becomes impossible to properly operate an optical communication system or the like to which the semiconductor laser module is applied,
It was a problem.

The present invention has been made to solve the above-mentioned conventional problems. An object of the present invention is to provide a highly reliable semiconductor laser module capable of optically coupling a laser diode and a lens unit for guiding a light beam of the laser diode to an optical fiber with high accuracy regardless of a change in a use environment temperature. It is in.

[0016]

In order to achieve the above-mentioned object, the present invention has the following structure to solve the problem. That is, the first invention provides a laser diode, an optical fiber that receives and transmits light emitted from the laser diode via a lens unit, a fixing member that supports the lens unit, A base for directly or indirectly mounting a laser diode, the laser diode, the lens portion, the fixing member, a package for accommodating the base, the base directly on the bottom plate of the package or a thermo module. A semiconductor laser module mounted via
Means for solving the problem is that the base has a structure in which deflection preventing means is formed at least on both sides of an optical coupling portion between the laser diode and the lens portion.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the deflection preventing means is orthogonal to an optical axis of the laser diode so as to surround at least an optical coupling portion between the laser diode and the lens portion. It is characterized by including a configuration in which the cross-sectional shape of the base in the cross section to be formed is substantially U-shaped.

Further, the third invention is directed to the first or second embodiment.
In addition to the configuration of the invention described above, the deflection preventing means is a means for solving the problem by a structure including walls formed on both sides of an optical coupling portion between the laser diode and the lens part.

Furthermore, a fourth invention provides a laser diode, an optical fiber for receiving and transmitting light emitted from the laser diode via a lens unit, a fixing member for supporting the lens unit, A semiconductor laser module including a member and a base for directly or indirectly mounting the laser diode, and the laser diode, the lens portion, the fixing member, and a package for housing the base, wherein the base includes the laser diode. Means for solving the problem is a configuration having a laser diode mounting member to be mounted and a fixing member mounting member that is disposed at a position avoiding the laser diode mounting region of the laser diode mounting member and mounts the fixing member.

According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, the fifth aspect further includes a thermo module on which the base is mounted, wherein the thermo module is mounted on a bottom plate of a package. A side plate member, a bottom plate side plate member, and a Peltier element tightly attached to these plate members, a laser diode mounting member of the base is arranged in contact with the thermo module, and the laser diode mounting member is Means for solving the problem is to solve the problem by a structure formed of a material having a linear expansion coefficient within a range between the linear expansion coefficient of the fixing member mounting member of the base and the linear expansion coefficient of the base side plate of the thermo module.

Further, the sixth invention is directed to the fourth or fifth embodiment.
In addition to the configuration of the invention described above, the laser diode mounting member is configured to have a higher thermal conductivity than the fixing member mounting member to achieve the object.

Further, a seventh invention provides a laser diode, an optical fiber for receiving and transmitting light emitted from the laser diode via a lens section, a fixing member for supporting the lens section, A semiconductor having a base for directly or indirectly mounting a member and the laser diode, a thermo module for mounting the base, and a package for housing the laser diode, the lens unit, the fixing member, the base, and the thermo module. A laser module, wherein the base is disposed in contact with the thermo module, and a laser diode mounting member for mounting the laser diode; and a laser diode mounting member is disposed at a position avoiding a laser diode mounting area. And a fixing member mounting member for mounting the fixing member, The bottom plate of the serial package is a means for solving the problems with the configuration that is formed of a material having a laser diode mounting member and the coefficient of linear expansion substantially the same of the base.

Further, an eighth invention provides a laser diode, an optical fiber for receiving and transmitting light emitted from the laser diode via a lens portion, a fixing member for supporting the lens portion, A base for directly or indirectly mounting the member and the laser diode, and a package for housing the laser diode, the lens portion, the fixing member, and the base, wherein the base is directly or directly on a bottom plate of the package; A semiconductor laser module mounted via a thermo module, wherein a fixed member mounting portion for mounting the fixed member is formed on the base, and the fixed member mounting portion and the fixed member are laser-welded. A first laser welded portion, and a second laser welded portion formed by laser welding the fixing member and the lens portion side, wherein the first laser welded portion is formed on the package bottom. And a means for solving the problems with a substantially same height as the height of the perpendicular arrangement relative.

According to a ninth aspect of the present invention, in addition to the configuration of the eighth aspect, the height of the first laser welded portion and the second laser welded portion with respect to the package bottom plate is transmitted from the laser diode through the lens portion. The height of the optical axis of the laser beam is the same as that of the laser beam.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same parts as those in the conventional example, and the overlapping description is omitted or simplified. FIG. 1 is a cross-sectional view showing a configuration of a main part of a first embodiment of a semiconductor laser module according to the present invention.

As shown in FIG. 1, the semiconductor laser module of the present embodiment comprises a laser diode 1, an optical fiber 4 having a lens portion 14, and a sleeve 3 as a lens portion fixing member for accommodating the lens portion 14. The optical fiber 4 and the lens portion 1 at the tip of the
The fixing members 6, 7 (7a, 7b) for supporting the laser diode 4, the base 2 on which the fixing members 6, 7 and the laser diode 1 are directly or indirectly mounted, and the thermo module 25 as a package 2
7 and is formed.

The lens portion 14 of the optical fiber 4 is a fiber lens, specifically, for example, a wedge-shaped anamorphic (rotationally asymmetric) lens having the configuration shown in FIG. As shown in FIG. 2, FIG. 3, and FIG. 7, the distal end side of the lens portion 14 composed of the wedge-shaped fiber lens has a ridge line 14a at the distal end located on the same plane as the active layer (not shown) of the laser diode 1. Thus, the laser diode 1 faces the laser light emitting end face 31 of the laser diode 1. Although the ridge 14a is shown in a straight line in the figure, it is actually formed into a curved surface when enlarged so that light can be efficiently incident on the core of the optical fiber 4.

In this embodiment, the base 2 includes a laser diode mounting member 8 on which the laser diode 1 is mounted,
It is composed of two parts, a fixing member mounting member 5 on which the fixing members 6 and 7 are mounted.

The laser diode mounting member 8 is disposed on the thermo module 25 in contact with the thermo module 25. As shown in FIGS. 1, 2, and 4, an LD bonding portion 21 formed integrally with the laser diode mounting member 8 is provided above the laser diode mounting member 8.
Are provided to form a laser diode mounting area. The fixing member mounting member 5 is arranged at a position avoiding the laser diode mounting region of the laser diode mounting member 8.

FIG. 4 is a perspective view showing the base 2 in an exploded state. Silver solder joint 4 shown by hatching in FIG.
6, the fixing member mounting member 5 is fixed on the laser diode mounting member 8.

The laser diode mounting member 8 is provided with the linear expansion coefficient of the fixing member mounting member 5 and the thermo module 2.
5 is formed of a material having a coefficient of linear expansion within a range between the coefficient of linear expansion of the base-side plate member 17 of No. 5.

More specifically, in this embodiment, the fixing member mounting member 5 is formed of Kovar, and the laser diode mounting member 8 is made of CuW10 of Cu—W alloy (weight ratio of Cu is 10%, W is 90%). ). Cu
The coefficient of linear expansion of W10 is 6.5 × 10 ⁻⁶ / K, Al ₂ O
_The coefficient of linear expansion of ₃ is 6.7 × 10 ⁻⁶ / K.

CuW10 has a thermal conductivity of 180 to 200.
(W / m · K), which is the thermal conductivity of Kovar 17
It has a thermal conductivity about 10 times that of １８18 (W / m · K).

The bottom plate 26 of the package 27 is made of CuW 10 made of the same material as the laser diode mounting member 8 of the base 2.
Accordingly, the linear expansion coefficient of the bottom plate 26 and the linear expansion coefficient of the laser diode mounting member 8 are the same.

As shown in FIGS. 1 to 3, a first laser welding portion formed by laser welding a fixing member mounting member 5 as a fixing member mounting portion and fixing members 6 and 7 of the optical fiber 4 and the sleeve 3. 10 are formed. The fixing member 6,
A second laser welded portion 11 (11a, 11b) formed by laser welding the sleeve 7 and the sleeve 3 is formed. The first laser welded portion 10 and the second laser welded portion 11 have substantially the same height in a direction perpendicular to the package bottom plate 26 (the difference in height is within ± 500 μm, preferably ± 50 μm).
(within μm).

The heights of the first and second laser welds 10 and 11 on the fixing member 6 side are the same as the center of the optical fiber 4 (here, the ridge 14a).

Here, when the fixing member mounting member 5 and the fixing members 6, 7 are laser-welded, the upper surfaces of the fixing member mounting member 5 and the fixing members 6, 7 are flush (within ± 100 μm). In this way, the laser weld 10
It is preferable because the height of the base can be easily made uniform.

The base 2 has bending preventing means formed at least on both sides of the optical coupling portion between the laser diode 1 and the optical fiber 4. As shown in FIGS. 3 and 4, the deflection preventing means is provided in a base region on both sides of the optical fiber 4 with a wall formed along the traveling direction of the light beam, here, the longitudinal direction of the optical fiber 4. It has a part 15.

FIG. 23 is a conceptual diagram showing the basic structure of the deflection preventing means provided with the wall portion 15. As shown in FIG. 23, the wall portions 15 are provided on both sides of the axis portion 33 that connects at least the laser light emitting end surface 31 of the laser diode 1 and the light receiving end 32 of the lens portion 14. Therefore, bending between the laser diode 1 and the optical fiber 4 is prevented,
A decrease in the optical coupling ratio is prevented.

In this embodiment, as shown in FIG. 3, the wall portion 15 is provided in the entire region in the longitudinal direction of the fixing member mounting member 5 (the region within the broken line frame B in FIG. 3).

In this embodiment, the wall 15 is formed integrally with the fixed member mounting member 5.
As shown in FIG. 5, the wall portion 15 stands at least above the bottom portion 16 of the fixed member mounting member 5. And
The fixing member mounting member 5 includes an axis portion 33 serving as the optical coupling portion.
Is formed in a substantially U-shaped cross section in a cross section orthogonal to the optical axis of the laser diode 1. Such a base configuration having a substantially U-shaped cross section constitutes a part of the bending prevention means in the present embodiment, and is extremely strong against bending in the longitudinal direction.

As shown in FIG. 4, one end of the wall portion 15 forms an arm portion 5e, and the bottom portion 1 of the fixing member mounting member 5
The laser diode mounting member 8 protrudes from the end of the laser diode mounting member 6 and extends to the area where the LD bonding portion 21 is provided. In the present embodiment, the arm 5e
Is formed, the contact area of the silver brazing portion 46 is increased. The connection configuration between the arm portion 5e and the laser diode mounting member 8 has a substantially U-shaped cross section in a cross section orthogonal to the optical axis of the laser diode 1, and is a part of the deflection preventing means in this embodiment. Is formed.

Further, as shown in FIGS. 3 and 4, in the fixing member mounting member 5, a fitting recess 37 is formed by the wall portion 15 and the wall portion 35 formed in a direction perpendicular to the wall portion 15. I have. The fixing members 6 and 7 are welded and fixed by the first laser welding portion 10 in a state of being fitted and housed in the fitting recess 37.

In this embodiment, when the fixing member mounting member 5 is formed, as shown in FIG. 4, for example, the fitting recesses 37 of the fixing members 6 and 7 and the insertion portion 38 of the sleeve 3 are used.
By molding into a hollow shape, the fixing member mounting member 5 in which the wall portion 15 and the fixing member fixing wall portion 35 are integrally formed can be obtained.

As shown in FIGS. 2 and 3, the fixing members 6, 7
Support the optical fibers 4 at positions spaced from each other in the longitudinal direction of the optical fibers 4. The fixing member 6 located on the side closest to the laser diode 1 is shown in FIG.
As shown in (b), the optical fiber 4 is formed of an integral component having a holding portion 28 for holding the optical fiber 4 from both sides.

As shown in FIG. 6B, when the holding member 28 is formed in an arm shape as shown in FIG. 6B, before fixing the laser welded portion 11b, the fixing member 6 is fixed with the laser welded portion 11a as a fulcrum. When the optical fiber 4 is rotated (this rotation is performed to align the laser diode 1 and the lens portion 14), the stress applied to the laser welded portion 11a causes the deformation stress of the arm of the holding portion 28 to be changed. It is dispersed and stress concentration can be prevented.

The fixing member mounting member 5 of the base 2 is provided so as to protrude in the longitudinal direction of the optical fiber from the optical fiber mounting side end (the right end in FIG. 1) of the thermomodule 25. Furthermore, the fixing member mounting member 5 is provided so as to protrude in the longitudinal direction of the optical fiber from an end portion of the laser diode mounting member 8 on the optical fiber mounting side. In the present embodiment, the sleeve 3 is fixed to a fixing member mounting member 5 protruding from the optical fiber mounting side end of the thermo module 25.

As shown in FIG. 2, the laser diode mounting member 8 has a reinforcing portion 20 for supporting the lower side of the fixing member 6 located near the laser diode 1 via the fixing member mounting member 5. The lower surface of the reinforcing portion 20 is not in contact with the thermo module 25. In the present embodiment, the reinforcing portion 20 is formed in a rectangular parallelepiped shape.

In this embodiment, as shown in FIG. 8A, the laser diode 1 is AuS
It is fixed on the heat sink 22 by a solder material 40 such as n. The heat sink 22 is fixed on the laser diode mounting member 8 by a solder material 41 such as AuSn. The heat sink 22 is formed of a high thermal conductive material such as AlN, SiC, diamond and the like.

As shown in FIG. 8B, the monitor photodiode fixing portion 39 is fixed on the laser diode mounting member 8 of the base 2 by a solder material 43.
The monitor photodiode fixing portion 39 is mainly formed of alumina. Monitor photodiode fixing part 39
An Au plating pattern 50 is formed on the surface of the substrate, and the photodiode 9 has AuSn and Au on the plating pattern.
It is fixed by a solder material 44 such as Si.

The present embodiment is configured as described above. In this embodiment, similarly to the conventional example, when the semiconductor laser module is used, light emitted from the laser diode 1 is received by the optical fiber 4. , Transmission.

At this time, also in this embodiment, the temperature of the laser diode 1 is controlled by the thermo module 25 as in the conventional example.

In this embodiment, the base 2 is composed of two parts, the laser diode mounting member 8 and the fixing member mounting member 5, and is optimized from the viewpoint of thermal expansion characteristics and heat conduction characteristics. Specifically, the laser diode mounting member 8 of the base 2 that contacts the base side plate member 17 of the thermo module 25 is formed by the linear expansion coefficient of the fixed member mounting member 5 provided on the upper side thereof and the base side plate material of the thermo module 25. It is formed of a material having a coefficient of linear expansion within a range between the coefficient of linear expansion of No. 17 (in other words, CuW10 having a coefficient of linear expansion between Kovar and Al ₂ O ₃ ). Therefore, the deflection of the base 2 caused by a change in the use environment temperature is reduced as compared with the case where the base 2 formed of Kovar is provided in direct contact with the base side plate 17 made of Al ₂ O ₃ as in the conventional example. .

Therefore, according to the present embodiment, it is possible to suppress a decrease in the optical coupling efficiency between the laser diode 1 and the optical fiber 4 due to a change in the use environment temperature.

The fixing member mounting member 5 is formed of Kovar, and Kovar has substantially the same linear expansion coefficient as the optical fiber 4. Therefore, adverse effects on the optical fiber 4 due to a difference in linear expansion coefficient from the optical fiber 4 can be suppressed.

The laser diode mounting member 8 is made of CuW10 having good thermal conductivity and having a thermal conductivity about 10 times that of Kovar. for that reason,
The heat generated by the laser diode 1 is transferred to a heat sink 2
2. The laser module 1 can be efficiently cooled by the thermo module 25 through the laser module mounting member 8 for efficient transmission to the thermo module 25 side.

Therefore, according to the present embodiment, the power consumption of the laser diode 1 and the thermo module 25 can be reduced, the semiconductor laser module can be reduced in power consumption, and the bending amount of the thermo module 25 can be reduced. be able to.

Further, according to the present embodiment, since the coefficient of linear expansion of the laser diode mounting member 8 and the bottom plate 26 of the package 27 are the same, when the temperature of the operating environment of the semiconductor laser module is changed, the thermo module 25 is changed.
The same stress is applied to the upper and lower sides of the
Is canceled out. Therefore, according to the present embodiment, it is possible to more efficiently suppress a decrease in the optical coupling efficiency between the laser diode 1 and the optical fiber 4 due to a change in the use environment temperature.

Further, in this embodiment, since the fixing member mounting member 5 is formed of Kovar having a low thermal conductivity, the laser weldability of the sleeve 3 in the fixing member mounting member 5 is good.

Further, according to the present embodiment, the base 2
Fixing member mounting member 5 and sleeve 3 for housing optical fiber
A first laser welded portion 10 formed by laser welding the fixing members 6, 7 and a second laser welded portion 11 formed by laser welding the fixing members 6, 7 and the sleeve 3 are formed by a package bottom plate 26. Are formed at substantially the same height in the direction perpendicular to. Therefore, even if the base 2 is slightly bent, it is possible to prevent the sleeve 3 from being largely displaced about the first laser welded portion 10 as a fulcrum due to the bending.

Therefore, in the semiconductor laser module of the present embodiment, a decrease in the optical coupling efficiency between the laser diode 1 and the optical fiber 4 can be suppressed even more efficiently.

Further, according to the present embodiment, the base 2
By forming the wall portion 15 on the fixing member mounting member 5 along the longitudinal direction of the optical fiber 4 to form a bending prevention means for preventing the base 2 from bending, The deflection of the base 2 can be suppressed.

The optical fiber 4 applied to the semiconductor laser module of this embodiment has a ridge 14a at the tip.
Has a wedge-shaped lens portion 14 parallel to the XZ plane. The optical coupling between the optical fiber 4 having this kind of lens portion 14 and the laser diode 1 is particularly susceptible to the displacement in the Y direction. Therefore, when the base 2 bends along the longitudinal direction of the optical fiber 4, the optical coupling efficiency between the laser diode 1 and the optical fiber 4 is apt to decrease significantly.

However, in the present embodiment, the bending of the base 2 in the longitudinal direction of the optical fiber can be suppressed by the bending preventing means as described above, so that the optical coupling efficiency between the laser diode 1 and the optical fiber 4 is reduced. Can be suppressed very efficiently.

In particular, in the semiconductor laser module of the present embodiment, the light emitted from the laser diode 1 enters the optical fiber 4 from the tip end of the optical fiber 4, so that the light between the laser diode 1 and the optical fiber 4 At the time of coupling, it is extremely important to suppress the displacement between the laser diode 1 and the laser light receiving end 32 of the optical fiber 4. Therefore, it is extremely important to suppress the deflection of the base 2 at the axis portion 33.

Similarly, when the fixing position of the sleeve 3 by the fixing member 6 shifts, the fixing position of the sleeve 3 by the fixing member 7 farther from the laser diode 1 than the fixing member 6 shifts, for example. The optical coupling efficiency between the optical fiber 4 and the optical fiber 4 is greatly reduced. For this reason, it is extremely important to suppress the bending of the base 2 in the area where the fixing member 6 is provided.

Therefore, in the present embodiment, the wall 15 is
Both sides of the axis portion 33 connecting the laser light emitting end face 31 of the laser diode 1 and the laser light receiving end 32 of the optical fiber 4 are provided. And the laser diode 1
The fixing member 6 is provided in an area along the longitudinal direction of the optical fiber of the fixing member mounting member 5 including both sides of the fixing member 6 located on the side closer to the optical fiber. Thereby, the bending of the base 2 in the optical fiber longitudinal direction in the area where the axis portion 33 and the fixing member 6 are provided is suppressed.

Further, in the present embodiment, the wall portion 15 is provided upright from the bottom portion 16 of the fixing member mounting member 5, and the deflection preventing means is orthogonal to the optical axis of the laser diode 1 so as to surround the axis portion 33. The cross-sectional shape of the base 2 at the cross section
It has a configuration formed in the shape of a letter. Therefore, the axis 3
3 can also be suppressed in the direction perpendicular to the optical axis of the laser diode (X direction in FIG. 3).

Therefore, in the semiconductor laser module of this embodiment, the deflection of the base 2 in accordance with a change in the operating temperature of the semiconductor laser module can be effectively suppressed, and the optical coupling efficiency between the laser diode 1 and the optical fiber 4 decreases. Can be suppressed very efficiently.

Further, in this embodiment, the wall 15 is formed integrally with the fixing member mounting member 5. For this reason, the wall portion 15 is formed of a separate component from the fixing member mounting member 5, and a decrease in strength due to the connection between the wall portion 15 and the fixing member mounting member 5, unlike when these are bonded, is prevented. . Therefore, the flexure of the base 2 can be effectively suppressed by the flexure prevention means having a simple configuration.

Further, according to the present embodiment, the fixing member 6 for supporting and fixing the optical fiber 4 on the side close to the laser diode 1 comprises the holding section 2 for holding the optical fiber 4 from both sides.
8 is formed by an integral part. for that reason,
Compared to the case where the fixing member 5 is formed by fixing parts supporting the optical fiber 4 one by one, there is a connecting portion 49 for connecting both sides of the holding portion 28 below the optical fiber 4,
The bending of the base 2 in the X direction in FIGS. 3 and 6 can be suppressed. Therefore, according to the present embodiment, a decrease in the optical coupling efficiency between the laser diode 1 and the optical fiber 4 can be suppressed even more efficiently.

Further, according to the present embodiment, the base 2
The fixing member mounting member 5 is provided so as to protrude in the longitudinal direction of the optical fiber from the end of the thermo module 25 on the optical fiber mounting side. Therefore, the portion (projecting portion) not in contact with the thermo module 25 is
Is not affected. If the protruding length L of the fixing member mounting member 5 (see FIG. 1) is too long, the adhesive strength of the protruding portion L to the laser diode mounting member 8 is insufficient due to the weight of the protruding portion. Since there is a possibility that the adhesive may be peeled off when subjected to vibration due to impact or the like, it is preferable that L ≦ 5 mm.

In this embodiment, since the sleeve 3 is fixed to the fixing member mounting member 5 protruding from the optical fiber mounting side end of the thermo module 25, the sleeve 3 is affected by the bending of the thermo module 25. Very difficult to receive. Therefore, the laser diode 1
The decrease in the optical coupling efficiency between the optical fiber 4 and the optical fiber 4 can be suppressed even more efficiently.

Further, according to this embodiment, the fixing member mounting member 5 is provided so as to protrude in the longitudinal direction of the optical fiber from the end of the laser diode mounting member 8 on the optical fiber mounting side. Therefore, it is possible to prevent the fixing members 6 and 7, the sleeve 3, and the optical fiber 4 mounted on the projecting portion from being affected by the bending of the laser diode mounting member 8. As a result, a decrease in the optical coupling efficiency between the laser diode 1 and the optical fiber 4 can be suppressed even more efficiently.

Further, according to the present embodiment, the laser diode mounting member 8 has the reinforcing portion 20 formed on the lower side of the fixing member 6 located closer to the laser diode 1. Therefore, even if the vibration in the Y direction is applied to the fixing member mounting member 5, the fulcrum of the vibration can be located farther from the laser diode 1 than the fixing member 6, and the laser diode 1 and the optical fiber 4 can be prevented from lowering in optical coupling efficiency.

Further, according to the present embodiment, the reinforcing portion 20
Is provided, the contact area between the laser diode mounting member 8 and the fixing member mounting member 5 can be increased, so that both can be mechanically and firmly fixed. Since the lower surface of the reinforcing portion 20 is not in contact with the thermo module 25, the reinforcing portion 20 is not affected by the bending of the thermo module 25.

As in the prior art, when the base 2 is bent as shown in FIG. 16A due to a change in the use environment temperature, for example, as shown in FIG. 16B, the base 2 is adjusted to the position shown by the chain line in the figure. The centered optical fiber 4 is shifted to the position shown by the solid line in the figure. Due to this shift, the distance between the laser light receiving end 32 of the optical fiber 4 and the laser diode 1 changes from A to B. Then, as shown by the characteristic line b in FIG. 9, the monitor tracking error ΔIm depending on the distance between the laser light receiving end 32 of the optical fiber 4 and the emission end face 31 of the laser diode 1 changes due to the temperature change in the operating environment of the semiconductor laser module. It changes greatly with. Here, the monitor tracking error ΔIm is defined as follows.

ΔIm = (Im (T) −Im (25 °))
/ Im (25 °) where Im (T) is the monitor current value at T (° C.)
m (25 °) is a monitor current value at 25 ° C.

For example, in the conventional semiconductor laser module, when the ambient temperature of the semiconductor laser module changes from 25 ° C. to 85 ° C., as shown by the characteristic line b,
The monitor tracking error changes by one cycle of the sin curve, and the amount of change is large.

On the other hand, according to this embodiment, FIG.
As shown by the characteristic line a, the monitor tracking error hardly changed from 0, and even when the ambient temperature reached 75 ° C., the value was 分 の of the change amount of the conventional example shown by the characteristic line b. It is about 1. That is, in the present embodiment, it is considered that the distance between the emission end face 31 of the laser diode 1 and the light receiving end 32 of the laser light of the optical fiber 4 does not greatly change even if the use environment temperature changes. It can be seen that the bending of No. 2 was effectively prevented.

FIG. 10 is a perspective view showing a main part of a semiconductor laser module according to a second embodiment of the present invention, in which the thermo module 25 and the package 27 are omitted. FIG. 11 is a plan view of the semiconductor laser module with the package 27 omitted, and FIG.
FIG. 12 is an exploded view showing the configuration of the base 2 according to the second embodiment.

The second embodiment is substantially the same as the first embodiment. The difference between the second embodiment and the first embodiment is that the base 2 has a structure similar to that of the first embodiment. Fixing member 5 and laser diode mounting member 8
Is configured as shown in FIGS. 10 to 12.

That is, in the second embodiment, the means for preventing the base 2 from bending is formed by both the fixing member mounting member 5 and the laser diode mounting member 8. In the second embodiment, the wall portions 15 provided on both sides of the axis portion 33 connecting the laser light emitting end face 31 of the laser diode 1 and the laser light receiving end 32 of the optical fiber 4.
And a fixing member 6 located on the side closer to the laser diode 1.
The wall portions 15 provided on both sides of the side portion are formed integrally with the laser diode mounting member 8.

The second embodiment is configured as described above, and the second embodiment can also provide substantially the same effects as the first embodiment.

The semiconductor laser module of the present invention of the type in which the lens portion 14 is constituted by a fiber lens is not limited to the above embodiments, but can take various embodiments. For example, when the deflection preventing means is provided on one side of the supporting portion of the optical fiber 4, a fixing member that supports the optical fibers 4 at positions spaced from each other in the longitudinal direction of the optical fibers 4 (the fixing member in each of the above embodiments) If the bending prevention means is provided at least on the side of the fixing member located closest to the laser diode 1 among the members 6, 7), it is possible to suppress the displacement of the support position of the optical fiber 4 on the side close to the laser diode 1. . Therefore, it is possible to efficiently suppress a decrease in optical coupling efficiency between the laser diode 1 and the optical fiber 4 due to the bending of the base 2. For this reason, it is preferable to provide the deflection preventing means at least on the side of the fixing member located closest to the laser diode 1.

In each of the above embodiments, the fixing members 7 located farthest from the laser diode 1 are fixed to the fixing members 7a,
However, as shown in FIGS. 13 (a), 13 (b) and 13 (c), the fixing member 7 is an integrated component having a holding portion 61 for holding the optical fiber 4 from both sides. It may be formed.

Two fixing members 7a, 7 sandwiching the sleeve 3
When b is provided, while the sleeve 3 can be firmly clamped and fixed, for example, as shown in FIG. 14, the inclination of the fixing members 7a and 7b with respect to the optical axis of the optical fiber 4 is different from each other, or the fixing member 7a and There is a possibility that it is difficult to make the gap between the sleeve 3 and the gap between the fixing member 7b and the sleeve 3 substantially equidistant. On the other hand, when the fixing member 7 is formed as an integral component as described above, the inclinations of the fixing members 7a and 7b with respect to the optical axis of the optical fiber 4 become equal to each other, and the gap can be easily adjusted to the same distance.

Therefore, when the fixing member 7 is formed as an integral part, it is possible to suppress a variation in fixing strength when the sleeve 3 and the fixing member 7 are fixed by welding by YAG welding or the like.

Since the contact portion between the fixing member 7 and the sleeve 3 is only subjected to laser irradiation for welding, it is preferable that the contact portion between the fixing member 7 and the sleeve 3 is small. As shown in FIGS. 13A and 13B, it is preferable that the holding portion 61 is formed in an arm shape.

Further, in each of the above embodiments, the base 2
The base 2 has a fixed member mounting portion for mounting the fixing members 6 and 7 and a mounting portion for the laser diode 1. It may be formed by one member formed on one plate. Also in this case, a wall member is provided, or the first laser welded portion 10 formed by laser welding the fixed member mounting portion and the fixed members 6 and 7 is welded to the fixed member 6 and the sleeve 3 by laser welding. By making the height of the second laser welded portion 11 in the direction perpendicular to the package bottom plate 26 substantially the same, displacement of the sleeve 3 caused when the base 2 is bent can be reduced. Can be made smaller than the semiconductor laser module. Then, it is possible to suppress a decrease in the optical coupling efficiency between the laser diode 1 and the optical fiber 4.

Furthermore, in each of the above embodiments, the optical fiber 4 has the configuration having the wedge-shaped lens portion 14, but the optical fiber 4 may have the configuration having the lens portion 14 of an anamorphic lens other than the wedge-shaped lens. OK, for example, FIG.
As shown in (a) and (b), a structure having a lens portion 14 of a fiber lens other than an anamorphic lens, such as a spherical lens whose entire end is formed in a conical shape and whose tip is formed in a spherical shape, may be used. Good.

Further, in each of the first and second embodiments, the laser diode mounting member 8 is
The reinforcing portion 2 is provided on the lower side of the fixing member 6 located on the side closest to
Although 0 is formed, the reinforcing portion 20 can be omitted. However, since the provision of the reinforcing portion 20 can suppress the vibration of the fixed member mounting member 5 in the Y direction in the drawing, it is preferable to provide the reinforcing portion 20. The shape of the reinforcing portion 20 is not particularly limited and may be appropriately set. For example, the reinforcing portion 20 may have a tapered surface as shown by oblique lines A in FIG.

Further, in each of the first and second embodiments, the fixing member 6 located on the side closest to the laser diode 1 is formed by an integral part having a holding portion 28 as shown in FIG. However, the configuration of the fixing member 6 is not particularly limited and is appropriately set. However, if the fixing member 6 is configured as in each of the above embodiments, the base 2
In the X direction can be suppressed.

Next, each embodiment of the semiconductor laser module of the present invention, in which the lens portion 14 is a discrete lens, will be described below.

FIG. 18 is a cross-sectional view of a main part of a semiconductor laser module according to a third embodiment of the present invention. FIG. 17 is a cross-sectional view of the semiconductor laser module according to the third embodiment. Is shown in a perspective view.

As shown in FIGS. 17 and 18, the semiconductor laser module of the third embodiment
And a discrete lens (first lens) 14 as a lens unit optically coupled to the laser diode 1. The discrete lens 14 and the laser diode 1 are mounted on a base 2, and the base 2 includes a laser diode mounting member 8 as a light emitting element mounting portion,
It has a discrete lens 14 and a fixing means mounting member 5 for mounting a lens holder 24 as a fixing member thereof.

The base 2, the laser diode 1, and the discrete lens 14 are housed in a package 27. The base 2 is directly fixed on the bottom plate 26 of the package 27, and the laser diode mounting member 8 is arranged in contact with the package bottom plate 26.

On the upper side of the laser diode mounting member 8, there is provided an LD bonding portion 21 formed integrally with the laser diode mounting member 8 to form a laser diode mounting area. The laser diode 1 is an LD
It is fixed on the bonding part 21 via a heat sink 22. The thermistor 29 is fixed on a fixing part 48 provided on the LD bonding part 21.

In the third embodiment, the laser diode mounting member 8 is made of a Cu—W alloy having a high thermal conductivity of 150 W / mK or more from the viewpoint of heat radiation of the heat generated from the laser diode 1. (Weight ratio of Cu is 20% and W is 80%). Therefore, also in the third embodiment, the heat generated from the laser diode 1 can be efficiently radiated.

On the rear side of the LD bonding portion 21 of the laser diode mounting member 8, a monitor photodiode fixing portion 39 to which a monitoring photodiode 9 is attached for monitoring the output of the laser diode 1 is shown in FIG.
7 is located at a position 47 indicated by hatching. The fixing means mounting member 5 is arranged on the laser diode mounting member 8 in front of the LD bonding portion 21. The fixing means mounting member 5 is fixed on the laser diode mounting member 8 by a silver solder joint 46 shown by hatching in FIG.

The fixing means mounting member 5 has a wall 5b extending in the optical axis direction (the optical axis direction of the laser diode 1) on both sides of the base 5a.
The cross-sectional shape in a cross section orthogonal to the optical axis is substantially U-shaped. The fixing means mounting member 5 has a side wall 5b.
An arm portion 5e is formed so as to protrude rearward from the rear end in the optical axis direction, thereby increasing the contact area of the silver brazing portion 46 and preventing the base 2 from warping. This arm 5e
The connection configuration between the laser diode mounting member 8 and the laser diode mounting member 8 also has a substantially U-shaped cross section in a cross section orthogonal to the optical axis of the laser diode 1.

As described above, the base 2 is formed to have a substantially U-shaped cross section perpendicular to the optical axis of the laser diode 1 so as to surround at least the optical coupling portion between the laser diode 1 and the discrete lens 14. Have been. The base configuration having a substantially U-shaped cross section including such a wall portion 5b is very strong against bending, and at least the base 2 of the optical coupling portion between the laser diode 1 and the discrete lens 14 is provided.
This constitutes a flexure prevention means for preventing flexure.

As shown in FIG. 17, the discrete lens 14 is fixed to a lens holder 24, and the lens holder 24 is mounted on a fixing means of the base 2 via a fixing member (lens holder sleeve) 6 as fixing means. It is fixed to the member 5. The lens holder 24 and the fixing member 6 have an F coefficient close to that of the glass material forming the discrete lens 14 and a good laser weldability.
It is made of Kovar (trademark) of an e-Ni-Co alloy.

A first laser welding portion 10 formed by laser welding the fixing means mounting member 5 and the fixing member 6 of the base 2;
The second laser welded portion 11 formed by laser welding the fixing member 6 and the lens holder 14 is connected to the bottom plate 2 of the package 27.
The height in the direction perpendicular to 6 is substantially the same.

An optical isolator 30 is disposed on the fixing means mounting member 5 for transmitting light passing through the discrete lens 14 and blocking light returning to the laser diode 1 side. The third laser welded portion 12 formed by laser welding the optical isolator 30 and the fixing means mounting member 5 has a height in a direction perpendicular to the bottom plate 26 of the package 27, the height of the first and second laser welds. Part 1
It is formed at substantially the same height as 0,11.

In the third embodiment, the U-shape is formed from the optical coupling portion between the laser diode 1 and the discrete lens 14 to the end on the side where the optical isolator 30 is mounted. .

The fixing means mounting member 5 has a side wall 5b.
The protruding wall portions 5c and 5d are formed so as to protrude in a direction orthogonal to the optical axis direction of the laser diode 1, and the fixing member 6 is inserted between the protruding wall portions 5c and 5d.

FIG. 22 shows the fixing means mounting member 5, the fixing member 6, and the optical isolator 30 along the line BB 'in FIG.
Indicates the positional relationship. As shown in FIG. 22, even when the module is warped in the α direction (the direction in which both ends in the optical axis direction are displaced upward), the protruding wall 5 d is interposed between the fixing member 6 and the optical isolator 30. Therefore, the warpage of the fixing means mounting member 5 in the α direction can be suppressed.

On the other hand, even when the module is warped in the β direction (direction in which both ends in the optical axis direction are displaced downward), the fixing member 6 is not in contact with the projecting wall portions 5c and 5d on both sides in the optical axis direction. Since the optical isolator 30 is fixed to the wall 5b by welding, warpage in the β direction can be suppressed.

In particular, the fixing member 6 and the protruding walls 5c, 5d
Means that laser welding is performed between surfaces formed in the direction perpendicular to the optical axis direction, so that only tensile stress or compressive stress is applied to warpage in the α and β directions, but shear stress is applied. Absent. Therefore, the occurrence of breakage of the laser welding point can be more effectively prevented. From this viewpoint, it is also possible to adopt a configuration in which the optical isolator 30 and the protruding wall portion 5d are laser-welded at a point indicated by reference numeral 10 'in FIG.

The height of the upper surface 45 of the wall 5b of the fixing means mounting member 5 is substantially equal to the height of the optical axis of the laser diode 1. Therefore, the heights of the first, second, and third laser welds 10, 11, and 12 are substantially the same as the height of the optical axis of the laser diode 1. Therefore, the optical axes of the discrete lens 14 and the optical isolator 30 are positioned on the basis of this height, and it is possible to suppress the displacement due to the warpage of the package and the base 2.

The fixing means mounting member 5 preferably has a thermal conductivity of 50 W / mK or less from the viewpoint of laser weldability between the fixing means mounting member 5 and the fixing part. In addition, the fixing means mounting member 5 preferably has a Young's modulus of 15 × 10 ³ kg / mm ² or more from the viewpoint of preventing the bending.
Further, since the fixing means mounting member 5 mounts an optical isolator, it is preferable that the fixing means mounting member 5 be a member having low magnetism (preferably no magnetism) so as not to impair the magnetism of the optical isolator.

In the third embodiment, the fixing means mounting member 5
Is formed by SUS430. SUS430 is
Thermal conductivity is 26.4 W / mK and Young's modulus is 20.
Since it is 4 × 10 ³ kg / mm ² and has low magnetism, it is very suitable as the fixing means mounting member 5.

As shown in FIG.
A through hole 51 is formed in a side wall of the light emitting device, and a light transmitting plate 52 for sealing a package is fixed to the through hole 51.
A holder 54 to which the second lens 53 is fixed is inserted and fixed in the through hole 51, and a ferrule holder 55 is fixed to one end side (right side in the figure) of the holder 54. A ferrule 56 is fixed to the ferrule holder 55, and an optical fiber (single mode optical fiber) 57 is inserted and fixed to the ferrule 56.

The third embodiment is configured as described above, and the laser light oscillated from the laser diode 1 is
The light is optically coupled to the discrete lens 14 and enters the optical isolator 30 through the discrete lens 14. The light transmitted through the optical isolator 30 is condensed on the incident side of the optical fiber 57 by the second lens 53, and is provided for a desired use through the optical fiber 57.

According to the third embodiment, the base 2 on which the laser diode 1 and the discrete lens 14 are mounted
The laser diode mounting member 8 and the fixing means mounting member 5
It is formed by these. The fixing means mounting member 5 is formed in a substantially U-shaped cross section at a cross section orthogonal to the optical axis of the laser diode 1 and is fixed on the laser diode mounting member 8. This constitutes a means for preventing deflection of the base 2, and the deflection of the base 2 can be suppressed by this means for preventing deflection.

Further, according to the third embodiment, the first laser welding portion 1 formed by laser welding the fixing member 6 for fixing the lens holder 24 and the fixing means mounting member 5 of the base 2 is provided.
0, and the second laser welded portion 11 formed by laser welding the fixing member 6 and the lens holder 24 are formed at substantially the same height (on the same surface), and thus are caused by the bending of the base 2. Optical axis deviation of the discrete lens 14 is prevented.

Therefore, according to the third embodiment, a semiconductor laser module which can more surely suppress a decrease in the optical coupling efficiency between the laser diode 1 and the discrete lens 14 and has a higher long-term reliability. be able to.

Further, according to the third embodiment, the optical isolator 30 is disposed on the fixing means mounting member 5 of the base 2 and the optical isolator 30 is laser-welded to the fixing means mounting member 5. Since the height of the laser weld 12 is substantially the same as that of the first and second laser welds, the displacement of the optical isolator 30 due to the bending of the base 2 can be suppressed.

Further, according to the third embodiment, the fixing means mounting member 5 is formed of SUS430,
Since S430 has a small thermal conductivity, the laser weldability is improved. Further, SUS430 has a high Young's modulus, so that the above-described bending prevention effect can be efficiently exhibited. further,
Since SUS430 has low magnetism, it does not impair the magnetism of the optical isolator 30 and can provide an excellent semiconductor laser module having good manufacturability and long-term reliability.

In the semiconductor laser module of the third embodiment, the thermo module 25 used in each of the first and second embodiments is not used, and the base 2 is directly connected to the bottom plate of the package 27. 26. Generally, when a semiconductor laser module is used as a submarine optical amplifier, a thermo module is not often used. The semiconductor laser module of the third embodiment can provide the above-described long-term reliability without using a thermo module. Therefore, the semiconductor laser module is particularly used as an excitation light source used in an optical amplifier for a submarine optical system or an underground optical system. It is suitable.

FIG. 20 shows a fourth embodiment of the semiconductor laser module. The semiconductor laser module of this embodiment also has a lens portion 14 similar to that of the third embodiment.
Is constituted by a discrete lens. The semiconductor laser module of the fourth embodiment is different from that of the third embodiment in that the base 2 is fixed to the bottom plate 26 of the package 27 via the thermo module 25, and other configurations are the same as those of the third embodiment. Is the same as

Although the semiconductor laser module of the fourth embodiment also has the same effect as the third embodiment, the stability of the temperature control of the laser diode 1 can be further improved by providing the thermo module 25. Is possible.

In the third and fourth embodiments, the fixing means mounting member 5 extends the light of the laser diode 1 from the optical coupling portion between the laser diode 1 and the discrete lens 14 to the end on the optical isolator 30 side. Although the cross section perpendicular to the axis has a substantially U-shaped cross section, at least the laser diode 1 and the discrete lens 1
In the optical coupling portion with the fixing member 4, the fixing means mounting member 5 may have a substantially U-shaped cross section.

Further, in the third and fourth embodiments, the base 2 has the lens mounting member 5 and the laser diode mounting member 8, but the base 2 has the lens mounting member on which the discrete lens 14 is mounted. 1 with part
It may be formed by three members.

Also in this case, the first laser welding portion 10 formed by laser welding the lens mounting portion and the fixing member 6 is used.
And the second laser welded portion 11 formed by laser welding the fixing member 6 and the lens holder 24 such that the height in the direction perpendicular to the bottom plate 26 of the package 27 is substantially the same. It is desirable. By doing so, the displacement of the discrete lens 14 caused when the base 2 is bent can be reduced as compared with the conventional semiconductor laser module, and the optical coupling efficiency between the laser diode 1 and the discrete lens 14 decreases. Can be suppressed.

Further, in the third and fourth embodiments,
Although the optical isolator 30 is fixed to the fixing means mounting member 5, the optical isolator 30 is not necessarily fixed to the fixing means mounting member 5.
May be omitted.

Further, in the third and fourth embodiments, the discrete lens 14 is used as a collimating lens.
Light can be coupled to the optical fiber 57 without using the optical fiber 3.

Further, in the third and fourth embodiments, the fixing member mounting member 5 of the base 2 is provided so as to protrude in the longitudinal direction of the optical fiber 4 from the optical fiber mounting side end of the laser diode mounting member 8. However, the fixing member mounting member 5 of the base 2 does not have to be provided to protrude from the laser diode mounting member 8 as described above. However,
When the fixing member mounting member 5 of the base 2 is provided so as to protrude from the laser diode mounting member 8 as described above, in the protruding region, it is possible to prevent the laser diode mounting member 8 from being affected by bending, and This is preferable because a reduction in the optical coupling efficiency between the optical fiber 4 and the optical fiber 4 can be suppressed.

Further, in the first and second embodiments, the base 2 is provided so as to protrude in the longitudinal direction of the optical fiber from the end of the thermo module 25 on the side where the optical fiber is mounted. It is not necessary to protrude from the thermo module 25 as shown in FIG. Also,
In the fourth embodiment, as shown in FIG. 20, the entire base 2 is configured to be mounted on the thermo module 25. However, similar to the first and second embodiments, The base 2 may be configured to protrude from the thermo module 25.

However, if the base 2 is provided so as to protrude from the thermo module 25 as described above, the base 2 is not directly affected by the bending of the thermo module 25 in the region of the base 2 protruding from the thermo module 25. Can be. For this purpose, for example, as in the first and second embodiments, the sleeve 3 is provided in the above-mentioned projecting region and fixed by a fixing component, so that the thermo module 25 is formed.
The displacement of the sleeve 3 due to the deflection of the optical fiber 4 can be suppressed, and the decrease in the optical coupling rate between the laser diode 1 and the optical fiber 4 can be suppressed.

Further, in each of the above embodiments, the laser diode mounting member 8 and the bottom plate 26 of the package 27 are preferably made of the same material to have the same linear expansion coefficient.
Laser diode mounting member 8 and bottom plate 2 of package 27
6 may be made of different materials as long as they have substantially the same linear expansion coefficient. It is preferable that the linear expansion coefficients of the laser diode mounting member 8 and the bottom plate 26 of the package 27 are substantially the same, but they may be different from each other.

Further, the structure of the deflection preventing means is not limited to the above embodiments, but may be appropriately set.

Further, in each of the first to fourth embodiments, the deflection preventing means causes the walls 15, 5b, 5e standing upright from the bottom 16 of the fixing member mounting member 5 to move in the traveling direction of the light beam. However, the configuration of the deflection preventing means is not particularly limited, and is appropriately set. For example, a rod-shaped or square-shaped member may be bonded and fixed to the fixed member mounting member 5 of the base 2.

[0135]

According to the semiconductor laser module of the first to third aspects of the present invention, the base is provided with a bending preventing means for preventing bending of the base of at least the optical coupling portion between the laser diode and the lens portion. Therefore, at least the bending of the base of the optical coupling portion can be suppressed by the bending preventing means. As a result, it is possible to suppress a decrease in the optical coupling efficiency between the laser diode and the lens unit (fiber lens or discrete lens) due to a change in the use environment temperature of the semiconductor laser module.

Further, according to the fourth aspect, the base is a laser diode mounting member for mounting the laser diode,
Since the laser diode mounting member is arranged at a position avoiding the laser diode mounting area, the fixing member mounting member for mounting the fixing member of the lens unit is configured.
The laser diode mounting member and the fixing member mounting member can be formed of different materials, and for example, the following effects of the fifth invention can be obtained.

According to the fifth aspect, for example, a laser diode mounting member is disposed in contact with the thermo module, and the linear expansion coefficient of the laser diode mounting member is determined by the linear expansion coefficient of the fixing member mounting member and the linear expansion coefficient of the thermo module. Since the base side plate is formed of a material having a linear expansion coefficient within a range between the linear expansion coefficient and the base side plate, a base having a greatly different linear expansion coefficient from the base side plate as in the conventional example is placed on the base side plate. Compared to the case where the optical fiber is provided in contact, the deflection of the base caused by the change in the use environment temperature can be reduced, and the decrease in the optical coupling efficiency between the laser diode and the optical fiber due to the change in the use environment temperature can be suppressed.

According to the sixth aspect of the present invention, since the thermal conductivity of the laser diode mounting member is set to be higher than that of the fixed member mounting member, the heat from the laser diode is removed by the laser diode mounting member. It can be released efficiently. Therefore, according to the sixth aspect,
It is possible to reduce the power consumption of the laser diode and the thermo module, suppress the bending of the thermo module during operation, and suppress the decrease in the optical coupling efficiency between the laser diode and the optical fiber due to the change in the use environment temperature. it can.

According to the seventh aspect of the present invention, the base is formed by the laser diode mounting member contactingly arranged on the thermo module and the fixing member mounting member above the laser diode mounting member.
Since the coefficient of linear expansion of the laser diode mounting member and the bottom plate of the package are substantially the same, the same stress is applied to both the upper and lower sides of the thermomodule when the operating temperature of the semiconductor laser module changes, thereby canceling the flexure of the thermomodule. In addition, it is possible to suppress a decrease in optical coupling efficiency between the laser diode and the optical fiber due to a change in the use environment temperature.

Further, according to the semiconductor laser module of the eighth invention, the first laser welded portion formed by laser welding the fixed member mounting portion of the base and the fixed member, and the fixed member and the lens portion side are formed by the laser. The second laser welded portion is characterized in that the height in the direction perpendicular to the package bottom plate is substantially the same. With this configuration, even if the base is slightly bent, the bending does not cause a large displacement of the lens unit.
It is possible to suppress a decrease in optical coupling efficiency between the laser diode and the lens unit.

In particular, by setting the height of the first laser welded portion and the second laser welded portion with respect to the package bottom plate to be the same as the height of the optical axis of the laser beam transmitted from the laser diode through the lens portion, The effect of suppressing the relative displacement between the laser diode and the lens portion due to the bending of the base is extremely high. As a result, it is possible to increase the optical coupling efficiency between the laser diode and the lens portion, and to stably maintain the characteristic of the high coupling efficiency for a long time.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment of a semiconductor laser module according to the present invention by a sectional view.

FIG. 2 is a perspective view illustrating a configuration of a main part of the semiconductor laser module of the embodiment, omitting a thermo module and a package.

FIG. 3 is a plan view showing a configuration of a main part of the semiconductor laser module of the embodiment, omitting a package.

FIG. 4 is an explanatory view showing an exploded view of a configuration of a base in the embodiment.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is an explanatory view showing a perspective configuration of a fixing member provided in the embodiment.

FIG. 7 shows an optical fiber 4 provided in the embodiment.
FIG. 3 is an explanatory diagram showing a configuration of a lens unit 14 of FIG.

FIG. 8 is a perspective explanatory view showing an arrangement region of a laser diode and an arrangement region of a monitor photodiode in the embodiment.

FIG. 9 is a graph showing a tracking error occurrence state due to a change in the ambient temperature in the embodiment described above, in comparison with a conventional example.

FIG. 10 shows a second example of the semiconductor laser module according to the present invention.
It is a perspective view which shows the principal part structure of embodiment example, omitting a thermo module and a package.

FIG. 11 is a plan view illustrating a configuration of a main part of the semiconductor laser module according to the second embodiment, omitting a package.

FIG. 12 is an explanatory view showing an exploded view of a configuration of a base in the second embodiment.

FIG. 13 is an explanatory view showing a fixing member applied to another embodiment of the semiconductor laser module according to the present invention.

FIG. 14 is an explanatory diagram schematically showing a state of displacement of the fixing member when the fixing member of the optical fiber provided on the far side from the laser diode is two members.

FIG. 15 is an explanatory diagram showing a cross-sectional configuration and a problem of a conventional semiconductor laser module.

FIG. 16 is an explanatory view schematically showing deflection of a base in the semiconductor laser module and accompanying displacement of the tip end of the optical fiber.

FIG. 17 shows a third example of the semiconductor laser module according to the present invention.
FIG. 2 is a perspective view illustrating a configuration around a base according to the embodiment.

FIG. 18 is a sectional view showing the configuration of a semiconductor laser module according to the third embodiment.

FIG. 19 is an explanatory diagram showing an exploded view of a configuration of a base in the third embodiment.

FIG. 20 is a fourth view of the semiconductor laser module according to the present invention.
It is explanatory drawing which shows an embodiment example by sectional drawing.

FIG. 21 is an explanatory diagram showing a cross section taken along line A-A ′ of FIG. 19;

FIG. 22 is an explanatory diagram showing a cross section taken along line B-B ′ of FIG. 17;

FIG. 23 is an explanatory diagram showing a relationship between an optical coupling portion between a laser diode and a lens unit and a deflection preventing unit.

24A and 24B are diagrams illustrating another example of the lens unit of the optical fiber, where FIG. 24A is a top view and FIG. 24B is a side view.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser diode 2 base 3 sleeve 4 optical fiber 5 fixing member mounting member 6, 7 fixing member 8 laser diode mounting member 10 first laser welded portion 11 second laser welded portion 14 lens portion 15 wall portion 17 base side plate 18 Bottom plate side plate 19 Peltier element 20 Reinforcing part 21 LD bonding plate 25 Thermo module 33 Axis part (optical coupling part)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Etsuji Katayama 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Kaoru Sekiguchi 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Seiwa Tateno 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. F-term (reference) 2H037 AA01 BA03 CA08 CA21 DA03 DA04 DA05 DA06 DA11 DA16 DA37 5F073 AB27 AB28 AB30 BA01 EA15 FA02 FA15 FA25 FA30

Claims (9)

[Claims] A laser diode, an optical fiber for receiving and transmitting light emitted from the laser diode via a lens unit, and a fixing member for supporting the lens unit;
A base that directly or indirectly mounts the fixing member and the laser diode; and a package that houses the laser diode, the lens unit, the fixing member, and the base, wherein the base is directly mounted on a bottom plate of the package. Or a semiconductor laser module mounted via a thermo module, wherein the base is provided with bending preventing means at least on both sides of an optical coupling portion between the laser diode and the lens portion. Semiconductor laser module. 2. A structure in which the deflection preventing means has a substantially U-shaped cross-section of a base in a cross section orthogonal to an optical axis of the laser diode so as to surround at least an optical coupling portion between the laser diode and the lens portion. The semiconductor laser module according to claim 1, comprising: 3. The semiconductor laser module according to claim 1, wherein the deflection preventing means includes walls formed on both sides of an optical coupling portion between the laser diode and the lens. 4. A laser diode, an optical fiber that receives and transmits light emitted from the laser diode via a lens unit, and a fixing member that supports the lens unit.
A semiconductor laser module having a base for directly or indirectly mounting the fixing member and the laser diode, and a package for housing the laser diode, the lens unit, the fixing member, and the base, wherein the base is the laser. A laser diode mounting member for mounting a diode, and a fixing member mounting member for mounting the fixing member disposed at a position avoiding the laser diode mounting region of the laser diode mounting member. Semiconductor laser module. 5. A thermo module having a base mounted thereon, wherein the thermo module is mounted on a bottom plate of the package, and the thermo module is tightly mounted on the base side plate, the bottom plate side plate, and these plates. A Peltier element, and a laser diode mounting member of the base is disposed in contact with the thermo module, and the laser diode mounting member is configured to have a linear expansion coefficient of a fixing member mounting member of the base and a base of the thermo module. The semiconductor laser module according to claim 4, wherein the semiconductor laser module is formed of a material having a linear expansion coefficient within a range between the linear expansion coefficient and the side plate material. 6. The semiconductor laser module according to claim 4, wherein the laser diode mounting member has a higher thermal conductivity than the fixing member mounting member. 7. A laser diode, an optical fiber for receiving and transmitting light emitted from the laser diode via a lens unit, and a fixing member for supporting the lens unit;
A base that directly or indirectly mounts the fixing member and the laser diode, a thermo module that mounts the base, and a package that houses the laser diode, the lens unit, the fixing member, the base, and the thermo module. A laser diode mounting member, wherein the base is disposed in contact with the thermo module and mounts the laser diode, and the laser diode mounting member is disposed at a position avoiding a laser diode mounting region of the laser diode mounting member. And a fixing member mounting member for mounting the fixing member, wherein the bottom plate of the package is formed of a material having substantially the same linear expansion coefficient as the laser diode mounting member of the base. Semiconductor laser module. 8. A laser diode, an optical fiber that receives and transmits light emitted from the laser diode via a lens unit, and a fixing member that supports the lens unit.
A base that directly or indirectly mounts the fixing member and the laser diode, and a package that houses the laser diode, the lens portion, the fixing member, and the base, wherein the base is directly mounted on a bottom plate of the package. Or a semiconductor laser module mounted via a thermo module, wherein the base is provided with a fixing member mounting portion for mounting the fixing member, and the fixed member mounting portion and the fixing member are laser-welded. The first laser welded portion and the second laser welded portion formed by laser welding the fixing member and the lens portion side have heights substantially equal to each other in a direction perpendicular to the package bottom plate. A semiconductor laser module, characterized in that: 9. The height of the first laser welded portion and the second laser welded portion with respect to the package bottom plate is the same as the height of the optical axis of the laser beam transmitted from the laser diode through the lens portion. The semiconductor laser module according to claim 8, wherein