JPH07147462A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To prevent the heat of the high temperature surface of a Peltier element from transferring to a low temperature surface in a semiconductor laser device having a semiconductor laser cooling structure. CONSTITUTION:The heat of the high temperature surface of a Peltier element is prevented from transferring to the low temperature surface of the Peltier element 2 by providing a heat insulating layer 9 between a package region, which comes in contact with the high temperature surface of the Peltier element 2, and a package region which is thermally connected to the low temperature surface of the Peltier element 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device having a cooling mechanism.

[0002]

2. Description of the Related Art A semiconductor laser is often used with its temperature kept constant even when the ambient temperature changes, for the purpose of keeping its optical output and oscillation wavelength stable. As a method for keeping the temperature of such a semiconductor laser constant, a method as shown in FIG. 2 is generally used. That is, the semiconductor laser 6 and the table for maintaining the optical system (optical system fixed substrate 3) are attached to the Peltier device 2. The surface of the Peltier device 2 opposite to the mounting surface of the optical system fixed substrate, which is the high temperature surface, is mounted on the package 1. A semiconductor laser 6 is fixed to the optical system fixing substrate 3 while being optically coupled to a fiber 5 by a lens 4. A thermistor 7 is mounted on the optical system fixing substrate 3 to monitor the temperature of the semiconductor laser 6. A portion of the fiber 5 taken out from the package 1 is sealed by a sealing material 8 such as solder for hermetically sealing the semiconductor laser device.

In the above-mentioned structure of the semiconductor laser device,
When the temperature of the semiconductor laser 6 rises due to the ambient temperature rising or the semiconductor laser 6 itself generating heat, the heat of the optical system fixing substrate 3 to which the semiconductor laser is fixed is the low temperature surface of the Peltier device 2. Are absorbed by the Peltier device and are removed to the outside of the semiconductor laser device through the high temperature surface on the opposite side of the Peltier device and the package 1. In this way, the temperature of the semiconductor laser is kept constant.

[0004]

In this conventional semiconductor laser device, the heat to be removed from the semiconductor laser device through the case from the high temperature surface of the Peltier device is passed through the case sealant, the fiber, and the optical system fixing substrate to the Peltier device. However, there is a problem in that the cooling capacity of the Peltier device is reduced because it is transmitted to the low temperature surface.

[0005]

SUMMARY OF THE INVENTION The present invention is a semiconductor laser device having a semiconductor laser held on an optical system fixed substrate whose temperature is controlled by a Peltier device, the whole being mounted in a package. A heat insulating layer is provided between a region of the package that is in contact with the hot surface of the Peltier device and a region of the package that is thermally connected to the cold face of the Peltier device.

[0006]

The present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a semiconductor laser device according to an embodiment of the present invention. As shown in the figure, the semiconductor laser 6 is fixed to the optical system fixing substrate 3 while being optically coupled to the phi 5 by the lens 4. Further, a thermistor 7 for monitoring the temperature of the semiconductor laser 6 is provided on the optical system fixed substrate 3. This optical system fixed substrate 3
Is installed on the low temperature surface of the Peltier device 2
The hot side, which is the opposite side of, is mounted on the package 1. A portion of the fiber 5 taken out from the package 1 is sealed by an In solder sealing material 8 for hermetically sealing the semiconductor laser device.

In the package 1 of this embodiment, the package region in contact with the high temperature surface of the Peltier element 2 has a thickness of about 1
The mm heat insulating material 9 thermally isolates the low-temperature surface of the Peltier device 2 from the package region that is thermally connected.

In the semiconductor laser device having such a structure, when the ambient temperature rises or when the semiconductor laser 6 itself generates heat, the temperature fluctuations of these semiconductor lasers are monitored by the thermistor 7, and the resistance value of the thermistor 7 is constant. The temperature of the semiconductor laser 6 is kept constant by cooling the optical system fixed substrate 3 by the Peltier device 2 so that At this time, the heat absorbed by the Peltier device 2 is removed to the outside of the semiconductor laser device through the package 1 in contact with the high temperature surface of the Peltier device 2. In this embodiment, the package 1 on the high temperature side of the Peltier element 2 is thermally insulated by the heat insulating layer 9, so that the heat absorbed by the Peltier element 2 is absorbed by the Peltier element as in the conventional semiconductor laser device. It is no longer transmitted to cold surfaces. Therefore, when a current of 100 mA was applied to the semiconductor laser, the operating temperature of the semiconductor laser device when maintaining the semiconductor laser temperature at 25 ° C. could be improved from 70 ° C. to 80 ° C.

In this embodiment, the heat conduction path from the high temperature surface to the low temperature surface of the Peltier device 2 is described as passing through the package 1, the sealing material 8, the fiber 5, and the optical system fixing substrate 3. Even if the bonding wire such as is a heat conduction path, the same effect can be obtained by thermally blocking the lead area to which the bonding wire is connected and the package area in contact with the hot surface of the Peltier element with a heat insulating material. Can be obtained.

[0010]

As described above, according to the present invention, the heat insulating layer is provided between the package region in contact with the high temperature surface of the Peltier device and the package region thermally connected to the low temperature surface of the Peltier device. The heat of the high temperature surface is not transferred to the low temperature surface, and the cooling capacity of the Peltier device is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor laser device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional semiconductor laser device.

[Explanation of symbols]

 1 Package 2 Peltier Element 3 Optical System Fixed Substrate 4 Lens 5 Fiber 6 Semiconductor Laser 7 Thermistor 8 Sealant 9 Heat Insulation Layer

Claims (1)

[Claims] 1. A semiconductor laser device having a semiconductor laser held on an optical system fixed substrate whose temperature is controlled by a Peltier element, the whole being mounted in a package,
A semiconductor laser device comprising a heat insulating layer between a region of a package in contact with a high temperature surface of a Peltier device and a region of a package thermally connected to a low temperature surface of a Peltier device.