JPH0453018Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a semiconductor laser temperature control device.
More specifically, the present invention relates to a semiconductor laser temperature control device that suppresses temperature changes in a semiconductor laser by supporting it with a constant temperature block.

<Prior art> Recently, in the field of laser printers, laser disc playback devices, optical communication equipment, etc., small, lightweight,
Semiconductor lasers, which have advantages such as ease of implementation and direct modulation, have come to be used as light sources.

However, semiconductor lasers have the characteristic that even if the current value is held constant, the output fluctuates due to temperature changes, and the wavelength of the output light also changes due to temperature changes. It has the characteristic of changing.

Therefore, for semiconductor lasers used in laser printers and laser disk playback devices, it is necessary to control the temperature of the semiconductor laser in order to stabilize the output light intensity. In order to stabilize the wavelength, it is necessary to control the temperature of the semiconductor laser.

Due to this need, conventional methods have been to maintain a constant temperature by placing the semiconductor laser inside a gas constant temperature bath, or to keep the temperature constant by placing the semiconductor laser inside a gas constant temperature bath. A semiconductor laser and a heating element are attached to each of the blocks, and the temperature of the constant temperature block is detected by a thermistor and the heating element is controlled in a feedback manner to maintain a relatively high predetermined temperature (Japanese Patent Laid-Open No. 176988/1983). ), as shown in Figure 6, a heating element is attached to one side of the L-shaped constant temperature block, a semiconductor laser is attached to a predetermined position on the other side, and the temperature of the case housing the semiconductor laser element is controlled by a thermistor. A device that attempts to maintain a relatively high predetermined temperature by detecting and controlling the heating element through feedback control (``Precise control device for semiconductor laser current and temperature using a microcomputer'')
Ogasawara et al., IEICE Technical Report OQE85-21) was provided.

<Problems to be solved by the invention> In the semiconductor laser temperature control device with the above configuration, the temperature of the semiconductor laser can be maintained at a predetermined temperature with high accuracy. Above, the overall size has increased,
There is a problem in that it cannot be used in devices that need to be miniaturized.

In the semiconductor laser temperature control device with the above configuration, the heat transfer system from the heating element is relatively symmetrical, so it is possible to set the temperature distribution in the part that supports the semiconductor laser to be relatively symmetrical. However, in reality, since it is necessary to supply a driving current to the semiconductor laser, the symmetry of the heat transfer system is impaired by forming a hole for inserting the lead wire, and in reality, However, there is a problem in that the temperature distribution becomes non-uniform.

Furthermore, when the influence of outside temperature etc. acts locally, it takes a long time for the influence to be transmitted to the whole area, so it is necessary to sufficiently suppress short-term temperature fluctuations in the vicinity of the semiconductor laser. In addition, since only a portion of the non-uniform temperature is detected by the thermistor to control the heating element, there is a problem that highly accurate temperature control cannot be performed.

In the semiconductor laser temperature control device with the above configuration, driving current can be easily supplied to the semiconductor laser. There is a problem in that a temperature gradient occurs between the semiconductor lasers and the temperature becomes non-uniform in the portion supporting the semiconductor laser.

In addition, the heating element is controlled by detecting only a portion of the above-mentioned non-uniform temperature using a thermistor.
There is a problem in that highly accurate temperature control cannot be performed.

<Purpose of the invention> This invention was made in view of the above-mentioned problems, and is a semiconductor laser temperature control device that has a simple configuration and can maintain a uniform temperature in the part that supports the semiconductor laser. is intended to provide.

<Means for Solving the Problems> In order to achieve the above object, the semiconductor laser temperature control device of this invention has the semiconductor laser at a predetermined position of a constant temperature block with good thermal conductivity that supports the semiconductor laser. A ring-shaped heat pipe is provided to surround the laser.

However, it is preferable that the constant temperature block is one that is supplied with heat by a heating element, and in this case, even if the heat is supplied from the outside of a heat pipe, or a ring Heat may be supplied from the central axis direction of the heat pipe.

<Function> In the semiconductor laser temperature control device having the above configuration, a ring-shaped heat pipe is provided at a predetermined position of a thermostatic block with good thermal conductivity that supports the semiconductor laser so as to surround the semiconductor laser. Therefore, the heat pipe has the same temperature over the entire range, and heat transfer from the heat pipe makes it possible to make the temperature distribution uniform in the portion supporting the semiconductor laser.

In addition, if the constant temperature block is one that is supplied with heat by a heating element, the temperature will be raised uniformly by the heat from the heating element over the entire range of the heat pipe, and the heat transfer from this heat pipe will be This makes it possible to make the temperature distribution of the portion supporting the semiconductor laser uniform.

Therefore, whether heat is supplied from outside the heat pipe or from the direction of the center axis of a ring-shaped heat pipe, the semiconductor The temperature distribution in the portion supporting the laser can be made uniform.

<Examples> Hereinafter, examples will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a front view showing an embodiment of the semiconductor laser temperature control device of this invention, and FIG. 2 is a central vertical cross-sectional view. An opening 3 is formed to support the heat pipe in an inserted state, and a ring-shaped heat pipe 4 is embedded around the opening 3. The flange is screwed to the support base 6 with a heating element 5 such as a Peltier element interposed therebetween.

A stopper plate 7 for holding the semiconductor laser 2 in a manner that prevents it from coming off is screwed to the back side of the thermostatic block 1.

In addition, a thermistor (not shown) is attached to the hole 8 formed in the vicinity of the semiconductor laser 2,
The amount of heat generated from the heating element 5 is controlled.

As the heat pipe 4, it is possible to use various configurations, but for example, by using a copper pipe with a heat pipe inside to lower the internal pressure and water injected inside. , high thermal conductivity can be achieved.

In the semiconductor laser temperature control device with the above configuration, the heat from the heating element 5 is transmitted from below, but the heat pipe 4 is maintained at a uniform temperature over the entire range. Due to heat conduction from the heat pipe 4, the temperature distribution near the opening 3 can be maintained uniformly.

In addition, the temperature of the part where the semiconductor laser 2 is attached is detected by a thermistor (not shown) to feedback-control the amount of heat generated from the heating element. It is possible to stabilize not only the intensity of the output light but also the wavelength of the output light by controlling the temperature with high precision.

FIG. 3 is a plan view showing another embodiment, and FIG. 4 is a central vertical cross-sectional view.The difference from the above embodiment is that the constant temperature block 1 is cylindrical, and a semiconductor laser 2 and a heat generating device are provided on both bottom surfaces. A stopper plate 7 is attached to the front side of the constant temperature block 1 at the point where the body 5 is attached.
A ring-shaped heat pipe 4 is attached to the boundary between the constant temperature block 1 and the stopper plate 7.
The only difference is that the constant temperature block 1 has an opening 9 formed at a predetermined position in which a lead wire for supplying a driving current to the semiconductor laser is inserted.

In the semiconductor laser temperature control device having the above configuration, the heat from the heating element 5 is transmitted from the rear of the constant temperature block 1. The symmetry of heat transfer is impaired by the opening 9, but
Since the temperature of the heat pipe 4 is maintained at a uniform temperature over the entire range, the temperature distribution in the portion where the semiconductor laser 2 is attached can be maintained uniform by heat conduction from the heat pipe 4.

In addition, the temperature of the part where the semiconductor laser 2 is attached is detected by a thermistor (not shown) to feedback-control the amount of heat generated from the heating element. It is possible to stabilize not only the intensity of the output light but also the wavelength of the output light by controlling the temperature with high precision.

Note that this invention is not limited to the above-mentioned embodiments; for example, it is possible to use any shape as the constant temperature block 1, and it is also possible to attach two or more heat pipes 4. ,
Furthermore, by using a heat absorbing element in place of the heating element 5, it is possible to maintain the constant temperature block 1 at a relatively low temperature, and various other design changes can be made without changing the gist of this invention. Is possible.

<Effects of the invention> As described above, in this invention, a ring-shaped heat pipe is attached to a predetermined position of the constant temperature block that supports the semiconductor laser so as to surround the semiconductor laser, so that the entire device is kept under uniform temperature conditions. The heat transfer from the heat pipe makes it possible to equalize the temperature of the semiconductor laser mounting area, which in turn stabilizes the output light intensity and wavelength of the semiconductor laser, and furthermore, reduces the overall size. It has the unique practical effect of being able to

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of the semiconductor laser temperature control device of this invention, Fig. 2 is a central longitudinal sectional view, Fig. 3 is a plan view showing another embodiment, and Fig. 4 is a central longitudinal sectional view. FIG. 5, and FIG. 6 are central vertical sectional views showing a conventional example. 1... Constant temperature block, 2... Semiconductor laser, 4
... Heat pipe, 5 ... Heating element.

Claims (1)

[Claims for Utility Model Registration] 1. A semiconductor characterized in that a ring-shaped heat pipe is provided at a predetermined position of a thermostatic block with good thermal conductivity that supports the semiconductor laser and surrounds the semiconductor laser. Laser temperature control device. 2. The semiconductor laser temperature control device according to claim 1, wherein the constant temperature block is supplied with heat by a heating element. 3. The semiconductor laser temperature control device according to claim 1, wherein the constant temperature block has heat absorbed by a heat absorber. 4. The semiconductor laser temperature control device according to claim 2 or 3, wherein the constant temperature block is thermally coupled to the outside of the heat pipe. 5. The semiconductor laser temperature control device according to claim 2 or 3, wherein the constant temperature block is thermally coupled in the direction of the center axis of the ring-shaped heat pipe.