JP2000349386A - Semiconductor laser module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a semiconductor laser module to be used with high output and at a high ambient temperature. SOLUTION: This module 10 is a semiconductor laser module, which has a package 11 to house a semiconductor laser element 13, a fixing board 16, and a Peltier module 12. Here, the semiconductor laser module 13 is fixed to the fixing board 16, and the fixing board 16 is fixed to a board on the cooling side of the Peltier module 12 fixed to the package 11, and a heat tnsulating material 21 is provided in the section without fixing board 16 on the board at the low-temperature side of the Peltier module 12.

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 a semiconductor laser module suitable for use in a high power and high temperature environment.

[0002]

2. Description of the Related Art In recent years, semiconductor lasers have been used in large quantities in the field of optical communications as light sources for signals or excitation light sources for optical fiber amplifiers. When a semiconductor laser is used as a signal light source or an excitation light source for optical communication, it is often used as a semiconductor laser module that is a device that optically couples laser light from a semiconductor laser to an optical fiber.

FIG. 8 shows an example of the structure of such a conventional semiconductor laser module 90. In the figure, reference numeral 11 denotes a package in which a Peltier module 12 is fixed. On the Peltier module 12, a fixed substrate 16 to which the semiconductor laser element 13, the thermistor 14, and the lens 15 are fixed is fixed. An optical fiber 17 is fixed in the through hole 11a of the side wall 11A of the package 11. Further, the inside of the package 11 is filled with a sealing gas 18 such as nitrogen or argon for the purpose of preventing the characteristics of the semiconductor laser element 13 from being deteriorated by oxidation. This semiconductor laser module 90 is usually mounted on a heat sink 80.

In the semiconductor laser module 90, the laser light emitted from the semiconductor laser
After being condensed by the optical fiber 17, the light is incident on the end face of the optical fiber 17 and is guided through the optical fiber 17 to be used for a desired use.

When a current is applied to drive the semiconductor laser element 13, the temperature of the semiconductor laser element 13 rises due to heat generated by the semiconductor laser element 13 itself. Causes a change in light output.

For this reason, the semiconductor laser device 13 is fixed by a thermistor 14 fixed near the semiconductor laser device 13.
The temperature of the semiconductor laser element 13 is kept constant by adjusting the current flowing through the Peltier module 12 using the measured value, thereby stabilizing the characteristics.

As a typical driving condition, the temperature of the semiconductor laser device 13 (the temperature sensed by the thermistor 14 in FIG. 8: Ts) is most commonly 25 ° C., and the ambient temperature (in FIG. 8, The temperature of the atmosphere in which the semiconductor laser module 90 is placed: Ta) is 7
It is required to be able to operate in a high temperature environment of 0 ° C. or higher. Therefore, the current flowing through the Peltier module 12 is controlled so that the temperature sensed by the thermistor 14 is always 25 ° C. under the environment temperature of 70 ° C. or higher, and the oscillation wavelength of the semiconductor laser element 13 and the light output Is kept constant.

Here, the Peltier module 12 used in the semiconductor laser module 90 has two P-type thermoelectric conversion elements, which are P-type semiconductors, and two N-type thermoelectric conversion elements, which are N-type semiconductors. It is arranged between the substrates 12a and 12b, and is formed by electrically connecting a P-type thermoelectric conversion element and an N-type thermoelectric conversion element in series.

By passing a DC current through the Peltier module 12 having the P-type thermoelectric conversion element and the N-type thermoelectric conversion element, heat is generated on the surface of the low-temperature side substrate 12a to cool the object.

The P-type thermoelectric conversion element of the Peltier module 12 used in the conventional semiconductor laser module 90 and N
The most common type of thermoelectric conversion element is about 20 to 30 pairs.

[0011]

By the way, such a semiconductor laser module has been required to operate at a high optical output and a high environmental temperature with an increase in the output of the system. . When the output power of the semiconductor laser device itself is increased to increase the output power of the semiconductor laser module,
Inevitably, the calorific value also increases.

Therefore, in order to use such a high-power semiconductor laser module in a higher temperature environment,
Heat generated from the semiconductor laser element must be discharged more efficiently than before.

For this reason, in a semiconductor laser module requiring such high output and high temperature operation, the number of P-type thermoelectric conversion elements and N-type thermoelectric conversion elements constituting the Peltier module must be 40 or more. Is done.

However, the use of such a large Peltier module for a semiconductor laser module has the following problems. That is, as shown in FIG. 8, the low-temperature side (cooling side) substrate 12a of the large Peltier module 12
Heat generated from the semiconductor laser element 13 spreads sufficiently and does not flow in the upper part distant from the semiconductor laser element 13 (that is, the peripheral part of the Peltier module 12).

As a result, in the peripheral portion of the Peltier module 12, the sealing gas hermetically sealed by the package 11 is cooled. The high-density gas cooled by this process is applied to the bottom plate 11 of the package 11.
8 flows into a high-temperature portion around the Peltier module 12 on the top of the package 11, where it is heated, and the R in FIG.
A vortex is generated as shown by.

For this reason, from the package bottom plate 11b to which the high-temperature side substrate 12b of the Peltier module 12 is fixed,
The heat circulates toward the low-temperature side substrate 12a of the Peltier module 12, and the cooling efficiency of the Peltier module 12 decreases.

In the conventional semiconductor laser module 90 having the above-described structure, even if the semiconductor laser element 13 is increased in output and at the same time the cooling efficiency is improved by enlarging the Peltier module 12,
There has been a problem that recirculation of heat due to the sealing gas in 1 becomes remarkable, cooling efficiency is reduced, and operation under a high temperature environment is not sufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the problem of heat exhaustion of such a conventional semiconductor laser module. The object of the present invention is to prevent heat from circulating in the semiconductor laser module and to increase the ambient temperature. An object of the present invention is to provide a semiconductor laser module usable below.

[0019]

Means for Solving the Problems In order to achieve the above object, the present invention provides means for solving the problems with the following constitution. That is, a semiconductor laser module according to a first aspect of the present invention includes a semiconductor laser device, a fixed substrate on which the semiconductor laser device is fixed, an optical fiber that receives laser light emitted from the semiconductor laser device, and a semiconductor laser device. Optical coupling means interposed between the optical fiber and the optical fiber for optically coupling laser light emitted from the semiconductor laser element to the optical fiber; and a Peltier module for cooling the fixed substrate on which the semiconductor laser element is fixed. And a semiconductor laser module having a package for accommodating the semiconductor laser element, the fixed substrate, and the Peltier module, wherein a sealing gas is sealed in the package, and a low-temperature side substrate of the Peltier module is provided. Solving the problem with a configuration in which a heat insulating material is provided in a portion where the fixed substrate is not provided It is a stage.

As the heat insulating material used in the first invention, for example, ceramics such as alumina (Al ₂ O ₃ ) or F
A metal material having a low thermal conductivity such as an e-Ni-Co alloy (product name Kovar) is used.

According to the first aspect of the present invention, since the heat insulating material is provided on the low-temperature side substrate of the Peltier module without the fixed substrate, the low-temperature side of the Peltier module is operated during operation of the semiconductor laser module. Since cooling of the sealing gas in the peripheral portion of the substrate is hindered, a decrease in the cooling efficiency of the Peltier module due to reflux of the sealing gas is suppressed, and a semiconductor laser module that can operate at a higher temperature is provided.

The semiconductor laser module according to the second aspect of the present invention includes a semiconductor laser device, a fixed substrate to which the semiconductor laser device is fixed, an optical fiber for receiving laser light emitted from the semiconductor laser device, An optical coupling means interposed between the semiconductor laser element and the optical fiber for optically coupling laser light emitted from the semiconductor laser element to the optical fiber; and cooling the fixed substrate on which the semiconductor laser element is fixed. Peltier module to
The semiconductor laser device, the fixed substrate, a semiconductor laser module having a package for accommodating the Peltier module, wherein a sealing gas is sealed in the package, the fixed substrate fixed the semiconductor laser device is This is a means for solving the problem with a configuration in which the entire surface of the low-temperature side substrate of the Peltier module is covered.

According to the second aspect of the present invention, the fixed substrate on which the semiconductor laser element is fixed covers the entire surface of the low-temperature side substrate of the Peltier module. In the peripheral portion of the side substrate, the sealing gas is not directly cooled by the low-temperature side substrate of the Peltier module,
A reduction in the cooling efficiency of the Peltier module due to the reflux of the sealing gas is suppressed.

Further, since the heat from the semiconductor laser element spreads to the peripheral portion through the fixed substrate, the cooling efficiency of the Peltier module is improved.

Therefore, a semiconductor laser module capable of operating at a higher temperature is provided.

The semiconductor laser module according to the third aspect of the present invention has a configuration in which a heat insulating material is provided on a peripheral portion of a fixed substrate in addition to the configuration of the second aspect of the present invention as means for solving the problem.

According to the third aspect of the present invention, since the fixed substrate on which the semiconductor laser element is fixed covers the entire surface of the low-temperature side substrate of the Peltier module, heat from the semiconductor laser element is more transmitted through the fixed substrate. And the heat insulating material is fixed on the periphery of the fixed substrate, so that the cooling of the sealing gas by the Peltier module is more efficiently suppressed as compared with the second aspect of the present invention, A decrease in the cooling efficiency of the Peltier module due to the reflux is more efficiently suppressed.

Therefore, a semiconductor laser module capable of operating at a higher temperature is provided.

Further, in the semiconductor laser module according to the fourth aspect of the present invention, in addition to the configuration according to any one of the second and third aspects of the present invention, in addition to the above, the fixed substrate has a heat in a direction parallel to the low-temperature side substrate of the Peltier module. This is a means for solving the problem with a configuration made of a material having a thermal conductivity anisotropy that is larger than the thermal conductivity in the vertical direction.

As the substrate material having heat conduction anisotropy used in the fourth invention, a fiber-reinforced composite material having a metal as a matrix can be used. Examples of such a composite material include carbon (C) and alumina (Al ₂ O).
₃ ) Silicon carbide (SiC) or the like as a dispersant,
Some of them use copper (Cu), aluminum (Al), titanium (Ti) or the like as a dispersant / matrix.

According to the fourth aspect of the present invention, since the heat conduction in the direction parallel to the low-temperature side substrate of the Peltier module of the fixed substrate becomes efficient, the heat generated from the semiconductor laser element is efficiently fixed. It reaches the periphery of the substrate.

For this reason, the cooling action in the peripheral portion of the low-temperature side substrate of the Peltier module is used for discharging heat generated from the semiconductor laser, and therefore, cooling of the sealing gas is suppressed.

Accordingly, a decrease in the cooling efficiency of the Peltier module due to the recirculation of the sealing gas is effectively suppressed, so that a semiconductor laser module capable of operating at a higher temperature is provided.

Further, in the semiconductor laser module according to the fifth aspect of the present invention, in addition to the configuration of any one of the second to fourth aspects of the present invention, the fixed substrate may spatially isolate the Peltier module in the package. The arrangement is used to solve the problem.

A semiconductor laser module according to a sixth aspect of the present invention has a problem in that, in addition to the configuration of the first aspect, a heat insulating material is arranged so as to spatially isolate the Peltier module in the package. Is a means to solve.

In the fifth or sixth aspect of the present invention, since the Peltier module is spatially separated in the package by the fixed substrate on which the semiconductor laser element is fixed or the heat insulating material, the Peltier module operates. Even in the state, the vortex does not occur due to the sealing gas cooled at the periphery of the low-temperature side substrate of the Peltier module, so that the reduction in the cooling efficiency of the Peltier module due to the reflux of the sealing gas is effectively suppressed. A semiconductor laser module capable of operating at a higher temperature is provided.

The semiconductor laser module according to the seventh aspect of the present invention provides a semiconductor laser device, a fixed substrate on which the semiconductor laser device is fixed, an optical fiber for receiving laser light emitted from the semiconductor laser device, An optical coupling means interposed between the semiconductor laser element and the optical fiber for optically coupling laser light emitted from the semiconductor laser element to the optical fiber; and cooling the fixed substrate on which the semiconductor laser element is fixed. Peltier module to
A semiconductor laser module having a package for accommodating the semiconductor laser element, the fixed substrate, and the Peltier module, wherein a heat insulating material is disposed on a portion of the bottom plate of the package where the Peltier module is not provided; The present invention is a means for solving the problem with a configuration in which the package is disposed in a recess formed by the bottom plate and the heat insulating material.

According to the seventh aspect of the present invention, the Peltier module is fixed to the concave portion including the package bottom plate and the heat insulating material, and the space between the Peltier module and the heat insulating material is narrow. Further, since the vicinity of the low-temperature side substrate of the Peltier module is surrounded by the heat insulating material, eddy current of the sealing gas due to the temperature difference between the Peltier module low-temperature side substrate and the package bottom plate is unlikely to occur. For this reason, a decrease in the cooling efficiency of the Peltier module due to the recirculation of the sealing gas is effectively suppressed, so that a semiconductor laser module capable of operating at a higher temperature is provided.

Further, in the semiconductor laser module according to the eighth aspect of the present invention, in addition to the configuration of any one of the first to seventh aspects, the sealing gas in the package is formed of helium or a mixed gas containing helium. This configuration is a means for solving the problem.

In the eighth aspect of the present invention, since the kinematic viscosity of helium is large, eddy current hardly occurs in the package. In addition, the temperature diffusion coefficient (the value obtained by dividing the thermal conductivity (κ) by the product of the density (ρ) and the specific heat at constant pressure (Cp) (κ / ρC
Since p)) is large, it is difficult to generate a large temperature gradient in the package. Therefore, generation of a vortex based on the temperature difference is prevented.

Accordingly, a decrease in the cooling efficiency of the Peltier module due to the recirculation of the sealing gas is effectively suppressed, so that a semiconductor laser module capable of operating at a higher temperature is provided.

The higher the proportion of helium in the sealing gas, the better, but if it is contained in a volume percentage of 30% or more, more preferably 60% or more, sufficient kinematic viscosity coefficient and temperature diffusion constant can be obtained. Therefore, the effect of the present invention is sufficient.

Further, in the semiconductor laser module of the ninth aspect, in addition to the constitution of the first to eighth aspects, the pressure of the sealing gas in the package is set to the atmospheric pressure (101.3 kP).
a) The following configuration is used as means for solving the problem.

According to the ninth aspect of the present invention, since the pressure of the sealing gas is low, the kinematic viscosity coefficient of the sealing gas increases, and the temperature diffusion constant also increases. Less likely.

Accordingly, a decrease in the cooling efficiency of the Peltier module due to the recirculation of the sealing gas is effectively suppressed, so that a semiconductor laser module capable of operating at a higher temperature is provided.

The pressure of the sealing gas is preferably as close to vacuum as possible, but a sufficient effect can be obtained if the pressure is 33 kPa or less.

When the pressure is reduced, the long-term stability of the package becomes a problem due to the difference from the atmospheric pressure.
If the pressure is 0 kPa or more, such a problem does not occur.

In the semiconductor laser module according to the tenth aspect of the present invention, the Peltier module has a P-type thermoelectric conversion element and an N-type thermoelectric conversion element.
As a means for solving the problem with a configuration in which the number of pairs composed of the P-type thermoelectric conversion element and the N-type thermoelectric conversion element is 40 or more. I have.

[0049]

Embodiments of the present invention will be described below in detail 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 will be omitted.

(First Embodiment) FIG. 1 shows a first embodiment of a semiconductor laser module according to the present invention. In the semiconductor laser module 10 shown in FIG. 1, the semiconductor laser element 13 is soldered on a fixed substrate 16 made of a CuW alloy via a heat sink (not shown) made of aluminum nitride. The fixed substrate 16 is further fixed on the Peltier module 12 by soldering. A heat insulating material 21 is fixed by soldering to a portion of the Peltier module 12 where there is no fixed substrate 16 on the low temperature side substrate 12a.

Although FIG. 1 shows a cross-sectional view including the optical axis of the semiconductor laser element 13, in the present embodiment, even on a cross section perpendicular to the optical axis, it is still on the low-temperature side substrate 12a of the Peltier module 12. A heat insulating material 21 is fixed to a peripheral portion where there is no fixed substrate 16. As a material of the heat insulating material 21, alumina (Al ₂ O ₃ ) having a low thermal conductivity and being a material of the low-temperature side substrate 12 a of the Peltier module 12 is used.
And those having a small difference in the coefficient of thermal expansion between them. As such a material, for example, alumina, an Fe—Ni—Co alloy (trade name: Kovar), stainless steel (SUS430), or the like can be used.

In the semiconductor laser module 10 according to this embodiment, since the heat insulating material 21 is fixed on the low-temperature side substrate 12a of the Peltier module 12 and on the peripheral portion where the fixed substrate 16 is not provided as described above, Even when the module 12 is driven, the temperature of the upper surface of the heat insulating material 21 does not decrease due to the thermal resistance of the heat insulating material 21.

Therefore, the sealing gas 18 near the heat insulating material 21 is hardly cooled, and even if the Peltier module 12 is driven under a high environmental temperature (Ta), the low-temperature side substrate 12a described in the conventional example of FIG. And package bottom plate 11
The eddy current based on the temperature difference from b is hardly generated.

Accordingly, a reduction in the cooling efficiency of the Peltier module 12 due to the recirculation of the sealing gas 18 is suppressed, so that a semiconductor laser module capable of operating at a higher temperature can be manufactured.

(Second Embodiment) In the present invention, the fixed substrate 16 is formed so as to cover the entire surface of the low-temperature side substrate 12a of the Peltier module 12 like the semiconductor laser module 20 shown in FIG. Good.

(Third Embodiment) Further, the semiconductor laser module 30 shown in FIG.
When the heat insulating material 21 is fixed as described above, a decrease in the cooling efficiency of the Peltier module 12 due to the recirculation of the sealing gas 18 is suppressed for the same reason as described above.

In the first to third embodiments, the fixed substrate 16 is made of CuW alloy.
When a material having thermal conductivity anisotropy whose thermal conductivity in the direction parallel to the low temperature side substrate 12a is larger than the thermal conductivity in the direction perpendicular to the low temperature side substrate 12a, heat generated from the semiconductor laser element 13 When conducting, it easily spreads in a plane parallel to the low temperature side substrate 12a.

As a fixed substrate material having such heat conduction anisotropy, a fiber-reinforced composite material having a metal matrix can be used. Examples of the fiber reinforced composite material include carbon (C), alumina (Al ₂ O ₃ ),
Silicon carbide (SiC) or the like is used as a dispersing material, and copper (C
u), molybdenum (Mo), tungsten (W), aluminum (Al), titanium (Ti) and the like are known.

As a method for producing such a fiber-reinforced composite material, for example, a composite material using copper or a copper alloy as a matrix and carbon fibers as a dispersing material will be described.

First, a powder of copper powder, copper alloy powder, molybdenum powder, tungsten powder or a mixture thereof is mixed with carbon and / or graphite fibers in a ball mill or the like, and the raw material mixture is pressed to compress the mixture. Obtain a molded product. This is further uniaxially compressed by hot isostatic pressing. In the composite material produced in this manner, fibers made of carbon and / or graphite are randomly oriented in the two-dimensional plane direction perpendicular to the compression direction of the metal matrix.

Such a composite material is disclosed, for example, in Japanese Patent Application No. 9-318888.

The above-mentioned fiber reinforced composite material is used so that the upper surface and the lower surface of the fixed substrate 16 are formed so as to be parallel to the orientation surface of the carbon fibers, so that the heat in the plane parallel to the cooling surface of the Peltier module 12 is obtained. Conductivity is Peltier module 1
A substrate having a thermal conductivity anisotropy that is larger than the thermal conductivity in the direction perpendicular to the cooling surface of No. 2 is obtained.

In such a fixed substrate 16, the thermal conductivity in the plane parallel to the cooling surface of the Peltier module 12 and the thermal conductivity in the direction perpendicular thereto are, for example, about 300 W / mK and 100 W, respectively.
Something like W / mK is obtained.

The orientation of the fibers can be one-dimensional instead of two-dimensional, and in this case, a larger heat conduction anisotropy can be obtained.

If the fixed substrate 16 configured as described above is used, the heat generated from the semiconductor laser element 13 is sufficiently conducted to the peripheral portion of the low-temperature side substrate 12a. Peltier module 12
Is used to discharge the heat generated from the semiconductor laser element 13, so that the surrounding sealing gas 1 is used.
8 will not be used to cool it. Therefore, eddy currents are less likely to be generated in the peripheral portion of the low-temperature side substrate 12a, and a decrease in the cooling efficiency of the Peltier module 12 due to the recirculation of the sealing gas 18 is suppressed. Can be made.

(Fourth Embodiment) (Fifth Embodiment) The present invention further relates to a semiconductor laser module 40 (fourth embodiment) shown in FIG. 4 and FIG.
Semiconductor laser module 50 (fifth embodiment example) shown in FIG.
Fixed substrate 1 on which semiconductor laser element 13 is fixed as shown in FIG.
The space in which the Peltier module 12 is placed in the package 11 and the upper space of the low-temperature side substrate 12a of the Peltier module 12 are substantially isolated from each other by the heat insulating material 6 or 6. That is, the fixed substrate 16 or the heat insulating material 21 is arranged so as to be in contact with or almost close to the side wall of the package 11.

Although FIGS. 4 and 5 show cross-sectional views including the optical axis of the semiconductor laser device 13, in the present embodiment, the fixed substrate 16 or the heat insulating material 21 is also formed in a cross section perpendicular to the optical axis. It is arranged so as to be in contact with or almost close to the side wall of the package 11.

As described above, the space in which the Peltier module 12 is mounted is isolated, so that the sealing gas 18 cooled on the low-temperature side substrate 12a is moved to the high-temperature side of the Peltier module 12 (the bottom plate 11b side of the package). Peltier module 1 due to reflux of sealing gas 18 because it does not flow
2, a decrease in the cooling efficiency is suppressed, and a semiconductor laser module capable of operating at a higher temperature can be manufactured.

(Sixth Embodiment) According to the present invention, as in a semiconductor laser module 60 shown in FIG. 6, a heat insulating material 22a is fixed to a peripheral portion on a package bottom plate 11b so as to be in contact with a side wall 11A. , The Peltier module 12 is fitted and fixed in a recess formed by the package bottom plate 11b and the heat insulating material 22a.

The height of the heat insulating material 22a to be fixed is desirably at least as high as the height of the Peltier module 12, but it is more preferable to fill the space above the fixed substrate.

(Seventh Embodiment) Further, as in a semiconductor laser module 70 shown in FIG. 7, a heat insulating material 2 fixed to the peripheral portion on the bottom plate 11b so as to be in contact with the side wall 11A.
The Peltier module 12 was fitted and fixed in the recess formed by the bottom plate 11b and the heat insulating material 22a in the package 11 having the package 2a, and the heat insulating material 22b was fixed after fixing the fixed substrate 16 to which the semiconductor laser 13 and the lens 15 were fixed. The package 11 is sealed with the lid 11d. The heat insulating material 22b is formed so as to occupy at least a portion serving as an optical path of laser light in a space inside the semiconductor laser module 70.

As described above, by arranging the heat insulating material 22a in a portion not obstructing the optical path of the laser beam inside the package 11 and minimizing the volume of the space occupied by the sealing gas 18, the temperature difference in the package 11 is reduced. As a result, a reduction in the cooling efficiency of the Peltier module 12 due to the generation of the vortex and the recirculation of the sealing gas 18 due to the vortex is suppressed, so that a semiconductor laser module capable of operating at a higher temperature can be manufactured.

(Other Embodiments) The First to Seventh Embodiments
In the embodiment of the present invention, the generation of the vortex due to the temperature difference inside the package 11 is suppressed by the structure inside the package 11. The generation of eddy current is also prevented by changing

That is, in the present invention, the generation of the vortex is suppressed by using a gas having a large kinematic viscosity coefficient or a temperature diffusion constant as the sealing gas 18.

As such a gas, for example, helium
Gas (Kinematic viscosity coefficient ν ≒ 1.1 × 10 ^-4m²/ S, temperature
Diffusion constant (κ / ρCp) ≒ 0.16m²/ Ks (room temperature,
Atmospheric pressure)) is preferred. By the way, the conventional sealing gas 18
The kinematic viscosity of nitrogen and argon used as
About 1.5 × 10 each^-5m²/ S, 1.3 × 10
^-5m²/ S (both room temperature and atmospheric pressure) and temperature diffusion
Each constant is about 0.021m²/ Ks, 0.019m
²/ Ks.

If the kinematic viscosity coefficient is large, the diffusion of the vector field of the gas flow velocity is likely to occur, so that the vortex is less likely to be generated.

When the temperature diffusion constant is large, the diffusion of the gas temperature field is apt to occur, so that it is difficult to form a large temperature gradient inside the package 11. Therefore, helium gas having a significantly higher kinematic viscosity coefficient and a larger temperature diffusion constant than the conventional sealing gas 18 is used.

As a result, the Peltier module 12 due to the eddy current generated due to the temperature difference inside the package 11
Since a decrease in the cooling efficiency of the semiconductor laser module is suppressed, a semiconductor laser module capable of operating at a higher temperature can be manufactured.

The higher the proportion of helium gas to be sealed, the better, but if it is contained in a volume percentage of 30% or more, more preferably 60% or more, sufficient kinematic viscosity coefficient and temperature diffusion constant can be obtained. Therefore, the effect of the present invention is sufficient.

Since the kinematic viscosity coefficient and the temperature diffusion constant increase as the pressure decreases, the inside of the package 11 is sealed under reduced pressure. As a result, generation of a vortex is suppressed, a decrease in the cooling efficiency of the Peltier module is suppressed, and a semiconductor laser module that can operate at a higher temperature can be manufactured.

The pressure of the sealing gas is preferably as close to vacuum as possible, but a sufficient effect can be obtained if the pressure is 33 kPa or less.

When the pressure is reduced, the long-term stability of the package becomes a problem due to the difference from the atmospheric pressure.
If the pressure is 0 kPa or more, such a problem does not occur.

[0083]

As described above, according to the semiconductor laser module of the present invention, the generation of the eddy current of the sealing gas in the package can be suppressed, and the cooling efficiency of the Peltier module can be prevented from lowering. The output of the laser element can be increased, and at the same time, the cooling efficiency can be improved by increasing the size of the Peltier module.

As a result, a semiconductor laser module that can be used under a high ambient temperature is provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first embodiment of a semiconductor laser module according to the present invention.

FIG. 2 is an explanatory view showing a second embodiment of the semiconductor laser module according to the present invention.

FIG. 3 is an explanatory view showing a third embodiment of the semiconductor laser module according to the present invention.

FIG. 4 is an explanatory view showing a fourth embodiment of the semiconductor laser module according to the present invention.

FIG. 5 is an explanatory view showing a fifth embodiment of the semiconductor laser module according to the present invention.

FIG. 6 is an explanatory view showing a sixth embodiment of the semiconductor laser module according to the present invention.

FIG. 7 is an explanatory view showing a seventh embodiment of the semiconductor laser module according to the present invention.

FIG. 8 is an explanatory view showing a conventional semiconductor laser module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor laser module 11 Package 12 Peltier module 13 Semiconductor laser element 14 Thermistor 15 Lens 16 Fixed substrate 17 Optical fiber 18 Sealing gas 21 Heat insulating material 22a Heat insulating material 22b Heat insulating material 20 Semiconductor laser module 30 Semiconductor laser module 40 Semiconductor laser module 50 Semiconductor Laser module 60 Semiconductor laser module 70 Semiconductor laser module

Claims (10)

[Claims] 1. A semiconductor laser device, a fixed substrate on which the semiconductor laser device is fixed, an optical fiber for receiving laser light emitted from the semiconductor laser device, and an optical fiber between the semiconductor laser device and the optical fiber. An optical coupling unit provided for optically coupling a laser beam emitted from the semiconductor laser element to the optical fiber; a Peltier module for cooling the fixed substrate on which the semiconductor laser element is fixed; the semiconductor laser element; A fixed substrate, a semiconductor laser module having a package accommodating the Peltier module, wherein a sealing gas is sealed in the package, and heat insulation is provided on a portion of the low-temperature side substrate of the Peltier module where the fixed substrate is not provided. A semiconductor laser module comprising a material. 2. A semiconductor laser device, a fixed substrate on which the semiconductor laser device is fixed, an optical fiber for receiving a laser beam emitted from the semiconductor laser device, and an optical fiber between the semiconductor laser device and the optical fiber. An optical coupling unit provided for optically coupling a laser beam emitted from the semiconductor laser element to the optical fiber; a Peltier module for cooling the fixed substrate on which the semiconductor laser element is fixed; the semiconductor laser element; A fixed substrate, a semiconductor laser module having a package accommodating the Peltier module, wherein a sealing gas is sealed in the package, and the fixed substrate on which the semiconductor laser element is fixed is a low-temperature side of the Peltier module. A semiconductor laser module covering the entire surface of a substrate. 3. The semiconductor laser module according to claim 2, wherein a heat insulating material is provided on a peripheral portion of the fixed substrate. 4. The fixed substrate is made of a material having a thermal conductivity anisotropy whose thermal conductivity in a direction parallel to the low-temperature substrate of the Peltier module is larger than thermal conductivity in a direction perpendicular to the low-temperature substrate. The semiconductor laser module according to claim 2 or 3. 5. The semiconductor laser module according to claim 2, wherein the fixed substrate is disposed in the package so as to spatially isolate the Peltier module. 6. The semiconductor laser module according to claim 1, wherein the heat insulating material is arranged in the package so as to spatially isolate the Peltier module. 7. A semiconductor laser device, a fixed substrate on which the semiconductor laser device is fixed, an optical fiber for receiving laser light emitted from the semiconductor laser device, and an optical fiber between the semiconductor laser device and the optical fiber. An optical coupling means for optically coupling a laser beam emitted from the semiconductor laser element to the optical fiber; a Peltier module for cooling the fixed substrate on which the semiconductor laser element is fixed; the semiconductor laser element; A fixed substrate, a semiconductor laser module having a package for accommodating the Peltier module, wherein a heat insulating material is disposed on a portion of the bottom plate of the package where the Peltier module is not provided, and the Peltier module is provided with the bottom plate of the package and the Peltier module. A semiconductor laser disposed in a recess made of a heat insulating material. The module. 8. The semiconductor laser module according to claim 1, wherein the sealing gas in the package is made of helium or a mixed gas containing helium. 9. The semiconductor laser module according to claim 1, wherein the pressure of the sealing gas in the package is equal to or lower than the atmospheric pressure (101.3 kPa). 10. A Peltier module, which is formed by electrically connecting a P-type thermoelectric conversion element and an N-type thermoelectric conversion element in series, and comprising a P-type thermoelectric conversion element and an N-type thermoelectric conversion element. 10. The semiconductor laser module according to claim 1, wherein the number is 40 or more.