JPS62109385A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To obtain a semiconductor laser which is mechanically stable and can be readily assembled by securing in contact the part between a block for placing a laser element and a package by a block holding member having low thermal conductivity. CONSTITUTION:An electron cooling element 5 is provided between one surface of a mounting block 4 for mounting fixedly a semiconductor laser element 1 and one wall of a hermetically sealed package 7 to secure the block 4 in the package 7. A block holding member 17 having low thermal conductivity is provided between the other surface of the block 4 and the other wall of the package 7 in such a semiconductor laser to hermetically secure the part between the block 4 and the package 7 by the member 7. a plurality of the member 7 formed by depositing metal film on both end faces of a columnar member such as soda glass having 5.5W.m<-1>.K<-1> of thermal conductivity are, for example, disposed, and the bottom 21 of the block 4 and the bottom 23 of the package 7 are bonded by bonds 18, 24 made of solder alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device incorporating an electrocooled Jul element for use as a light source in an optical communication system.

BACKGROUND OF THE INVENTION In general, since semiconductor lasers are threshold devices, a decrease in optical output and deterioration are accelerated as the temperature increases. Changes in ambient temperature also cause harmful noise sources in optical communication systems, such as mode hopping and temperature shifts in the center wavelength.

For this reason, there is a need for a semiconductor laser device that can operate stably without being affected by temperature changes, and conventional methods have been proposed to keep the temperature of a semiconductor laser element constant using a small temperature regulator.

- For example, there is a presentation by Mr. Aoki et al. entitled "Reliability Test of Single-mode Optical Fiber Laser Diode Module with Built-in Thermoelectric Cooling Element" (IEICE, 1985, National Conference of Optical and Radio Division No. 333). Figure 4 shows its basic structure. As shown in the figure, a semiconductor laser probe 1, a Rayleigh output monitor element 2, a first optical fiber coupling lens 8 to an optical fiber 10, and a temperature measurement thermistor 3 are mounted on a block 4, and the block 4 is fixed to the side plate 6 of the airtight package 7 via the electronic cooling L1 element 5.

Further, the terminal member 11 containing the optical fiber 10 and the second optical fiber coupling lens 9 are hermetically fixed in the airtight package 7. In the figure, 12 is a lead wire, and 13 is a lead wire.
1 to 16 each indicate a fixing agent.

When the optical fiber 10 is a single mode fiber, the semiconductor laser element 1, the first optical fiber coupling lens 8, and the second
The assembly precision of the optical fiber coupling lens 9 and the optical fiber 10 is required to be on the order of several μm, and the assembly machine must also maintain this precision.

However, the conventional structure shown in FIG. 4 is not suitable for meeting the above requirements and has the following drawbacks. First, since the block 4 is fixed via the electronic cooling element 5, it is supported at one end, and is unstable against large vibrations and shocks.

Second, although a Beltier element is used as the electronic cooling element 5, the heat resistance temperature of the electronic cooling element 5 made of the Beltier element is as low as about 120°C.

In other words, this means that the fixing temperature of the fixing agents 13 and 16 used must be 120°C or less, and the operating temperature of the semiconductor laser device is restricted by the heat resistance temperature of the fixing agents themselves. .

Thirdly, as a fixing agent, an inorganic one is preferable since it is necessary to prevent the generation of harmful gases that cause clouding of the lens. For example, a low melting point solder of 120° C. or lower is suitable. However, even in this case, in order to widen the usable temperature range and operate the semiconductor laser device stably, it is necessary to use a solder material with a melting point close to 120'C. On the other hand, there was a problem in that it became very difficult to control the melting temperature.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a semiconductor laser v device that is mechanically stable and easy to assemble.

Another object of the present invention is to provide a semiconductor laser device that can be firmly fixed using a high melting point adhesive without being limited by the temperature limit of the electronic cooling element.

Structure of the Invention According to the present invention, a semiconductor laser device, a mounting block on which the semiconductor laser device is firmly mounted, and one surface of the block and one surface of the package for fixing the mounting block in an airtight package. A semiconductor laser device including a thermoelectric cooling element provided between the block and a wall surface, wherein a block holding member with low thermal conductivity is provided between the other surface of the block and the loose wall surface of the package, There is obtained a semiconductor laser device characterized in that the block and the package are closely fixed by a block holding member.

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of one embodiment of the present invention, and FIG. 2 is a partial perspective view thereof, and the same tongue portions as in FIG. 4 are designated by the same reference numerals. Semiconductor laser element 1 and laser light monitor element 1
9, an optical fiber coupling lens 8 to an optical fiber 10, and a thermistor 3 for temperature measurement are arranged and mounted at predetermined positions on the block 4, as in the conventional example. The electronic cooling element 5 made of a Bertier element is arranged between the side surface 20 of the block 4 and the wall surface 22 of the airtight package 7, and are tightly fixed to each other. Further, a block holding member 17 made of a rigid body with low thermal conductivity is arranged between the bottom surface portion 21 of the block 4 and the bottom surface portion 23 of the airtight package 7. It is firmly fixed.

This block holding member 17 holds the block 24 and has a low thermal conductivity and has a contact surface with the package as small as possible in order to improve the cold IJ1 effect of the electronic cold fil element 5. For example, a plurality of cylindrical members such as soda glass having a thermal conductivity of 5.5 W-m-1·K-1 with metal films deposited on both end surfaces are arranged, and the bottom surface 21 of the block 4 and the bottom surface of the package 7 are arranged. Part 3
0 and 0 with adhesives 18 and 24 made of a solder alloy having a melting point of 120'C or higher, respectively.

The lead 12 is for taking out an electrode from the semiconductor laser element 1 or the like.

With this structure, -40"0 to 65°
It was found that almost no optical axis deviation occurred in the temperature range of C, and that the optical output under normal room temperature conditions could be guaranteed. The semiconductor laser device 1 used has an emission S wavelength of 1fi 1 and 3 μ
m, Ti current value value 20 mA (at 25 ° V),
A single mode fiber was used as the optical fiber 10, and a focusing rod lens was used as the optical fiber coupling lens 8. Moreover, the operating voltage of the electronic cooling element 5 is 1.4V (0.6A/
65°C).

Note that the same characteristics can be obtained when ceramic (thermal conductivity of 30 W-m-1·K-1 or less) is used as the material of the block holding member 17.

Side part 2 of block 4 equipped with semiconductor laser element 1 etc.
By arranging the electronic cooling element 5 at 2 and attaching the block holding member 17 to the bottom surface 21 of the block 4 and tightly fixing it to the airtight package 7, the block 4 is held from the entrance direction to the airtight package 7, The structure is stable against shooting and impact.

Further, since the electronic cooling element 5 and the block holding member 17 are separately attached to the airtight package 7, the block 4 can be assembled into the airtight package 7 before the electronic cooling element 5 is attached. That is, a solder alloy or the like having a higher melting point can be used without being limited by the heat resistance temperature of the electronic cooling element 5, and the temperature at which the semiconductor laser device can be used can be increased. Furthermore, the precision in controlling the melting temperature of the solder alloy is relaxed.

Furthermore, the height of the thermoelectric cooling element 5 determines the focal distance between the coupling lens 8 and the optical fiber 10, and the height of the block holding member 17 facilitates positioning in the direction perpendicular to the optical axis. , it is expected that the workability of assembling into the airtight package 7 will be improved.

Since the block holding member 17 is made of a material with low thermal conductivity and the contact area with the block 4 or the airtight package 7 is small, direct heat conduction between the block 4 and the airtight package 7 can be reduced, which is different from the conventional example. Compared to this, the cooling effect is not impaired.

Further, although the block holding member 17 shown in this embodiment is cylindrical, it is also possible to change the shape of the block holding member 25 to a plate-like shape as shown in FIG. It is also possible to replace it with polymer materials such as , ceramics, amorphous (non-crystalline), and even invar.

Since the structure is designed to have the effects of the invention, it is mechanically stable and has the effect of improving assembly accuracy. In addition, since the surface of the block that is different from the surface on which the electronic cooling element is mounted is attached to the package first, it is possible to use an adhesive with a high melting point, making it possible to increase the temperature at which it can be used as a semiconductor laser. becomes.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a partial perspective view of FIG. 1, and FIG. 3 is a perspective view of a portion of a modification of the present invention.
FIG. 4 is a cross-sectional view showing the structure of a conventional example. Explanation of symbols of main parts 1...Semiconductor laser element 4...Block 5...Electronic cooling element 7...Airtight package 10... optical fiber

Claims (1)

[Claims] A semiconductor laser device, a mounting block on which the semiconductor laser device is firmly mounted, and an electronic device provided between one surface of the block and one wall surface of the package to fix the mounting block inside the airtight package. A semiconductor laser device including a cooling element, wherein a block holding member with low thermal conductivity is provided between the other surface of the block and the other wall surface of the package, and the block holding member allows the block and the package to be cooled. A semiconductor laser device characterized in that the semiconductor laser device is formed by closely fixing the space between the semiconductor laser and the semiconductor laser.