JPH01265583A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To improve a device of this design in a heat dissipating property by a method wherein a photodetector is formed independently of a substrate on which a semiconductor element is mounted, and the photodetector is fixed to the substrate through the intermediary of an optional waveguide means. CONSTITUTION:A semiconductor laser element 2 is fixed onto a part of a surface of a substrate 1 excellent in a thermal conductivity. A photodetector 7 is fixed onto another part of the surface of the substrate 1 through the intermediary of an optical waveguide means which conducts a monitoring ray emitted from the element 2. When the element 2 is turned ON to start operating, intrinsic laser rays 11 are projected from a laser rays projecting end face 5. A monitoring ray 12 is projected from a laser ray projecting end face 6, the ray 12 is made to be incident on a transparent conductive bonding agent 10 and detected as a waveguide light by a photodetector 8. By these processes, a substrate excellent in A thermal conductivity can be used, so that a device is improved in a heat dissipating property.

Description

[Detailed description of the invention] The present invention will be described in the following order.

A. Field of industrial application B1 Overview of the invention C0 Prior art "Fig. 3" D. Problem to be solved by the invention E1 Means for solving the problem F0 Effect G. Examples [Fig. 1, [Figure 2] H6 Effects of the Invention (A. Field of Industrial Application) The present invention relates to a semiconductor laser device, and particularly to a semiconductor laser device equipped with a photodetector that monitors the optical output of a semiconductor laser element.

(B. Summary of the Invention) In the semiconductor laser device described above, the present invention includes mounting the semiconductor laser element on a substrate with good thermal conductivity in order to improve heat dissipation, and mounting a photodetector on the substrate with good thermal conductivity. Monitor light emitted from a semiconductor laser element fixed via a wave means is guided to a photodetector by an optical wave guide means.

(C, Prior Art) [Figure 3] A semiconductor laser device used as a light source for optical pickup in compact disc players, laser disc players, etc. is a semiconductor laser device that generates laser light, as introduced in Japanese Patent Application No. 72565/1983. In addition to the laser element, it is usually equipped with a photodetector that monitors the laser light in order to control the intensity of the monitor light to be kept constant.

FIG. 3 shows a conventional example of such a semiconductor laser device. In the figure, a is a semiconductor substrate made of silicon, b is a semiconductor laser device fixed on a part of the semiconductor substrate a, C is an active layer of the semiconductor laser device, and d is an original layer of the semiconductor laser device. The end face e emits a laser beam, that is, the laser light used for signal reading, and e is the monitor light emitting end face which is the opposite end face. A photodiode f is formed on the surface of the semiconductor substrate a, and receives monitor light emitted from the semiconductor laser element.

(D. Problems to be Solved by the Invention) The conventional semiconductor laser device shown in FIG. 3 has a problem of poor heat dissipation, which shortens the life of the semiconductor laser element. This is because the substrate a on which the semiconductor laser element is mounted is
This is because it is made of a silicon semiconductor substrate and has poor thermal conductivity compared to copper or the like.

The present invention has been made to solve these problems, and an object of the present invention is to improve the heat dissipation performance of a semiconductor laser device equipped with a photodetector that monitors the optical output of a semiconductor laser element.

(E. Means for Solving the Problems) In order to solve the above problems, the semiconductor laser device of the present invention has the following steps:
The semiconductor laser device is mounted on a substrate with good thermal conductivity, and a photodetector is fixed on the substrate with good thermal conductivity via an optical waveguide, and the monitor light emitted from the semiconductor laser device is detected by the photodetector using the optical waveguide. It is characterized by being designed to lead to.

(F. Effect) According to the semiconductor laser device of the present invention, the photodetector is not formed on the substrate on which the semiconductor laser element is mounted, but is formed separately from the substrate, and the photodetector is attached to the substrate via the optical waveguide. Since it is fixed, a substrate with better thermal conductivity than a silicon semiconductor substrate can be used instead of a silicon semiconductor substrate. Therefore, the heat dissipation of the semiconductor laser device can be improved.

Since the laser light emitted from the semiconductor laser element can be guided to the photodetector via the optical waveguide means, the output laser light of the semiconductor laser element can be monitored by the photodetector without any trouble.

(G. Embodiment) [FIGS. 1 and 2] Hereinafter, the semiconductor laser device of the present invention will be described in detail according to the illustrated embodiment.

1 and 2 show one embodiment of the semiconductor laser device of the present invention, with FIG. 1 being a perspective view and FIG. 2 being a sectional view.

1 is a substrate made of, for example, copper C'u; 2 is a semiconductor laser element mounted on a portion of the substrate 1 via a solder layer 3; 4 is an active layer; and 5 is a laser beam emitting device that emits the original laser beam. The end face 6 is a monitor light emitting end face, the monitor light emitting end face 6 faces toward the center of the substrate 1, and the laser light emitting end face 5 faces outward.

A photodetector 7 has a photodiode 9 formed on the surface of a silicon semiconductor substrate, and is bonded to the substrate 1 with a transparent conductive adhesive 10 with its light-receiving surface facing downward.

In this semiconductor laser device, when the semiconductor laser element 2 is turned on, the original laser beam 11 is emitted from the laser beam emitting end face 5.
is emitted, a monitor light 12 is emitted from the laser light emitting end face 6, the monitor light 12 enters the transparent conductive adhesive 10, and is received by the photodetector 8 as waveguide light.

This semiconductor laser device has good heat dissipation because the substrate 1 is made of copper, a material with very good thermal conductivity. By guiding the monitor light 12 emitted from the optical waveguide 2 to the photodetector 7 using the transparent conductive adhesive 10, the semiconductor laser device 2 can be monitored without any trouble.

In this embodiment, the adhesive 10 plays the role of the optical waveguide, but the thin optical waveguide is fixed to the light receiving surface of the photodetector, and then the optical waveguide is attached to the substrate 1 with an ordinary adhesive. The present invention can be implemented in various ways, such as by being fixed.

(H, Effects of the Invention) As described above, in the semiconductor laser device of the present invention, the semiconductor laser element is fixed on a part of the surface of the substrate with good thermal conductivity, and the semiconductor laser element is fixed on the other part. This device is characterized in that a photodetector is fixed via an optical waveguide that guides monitor light.

Therefore, according to the semiconductor laser device of the present invention, the photodetector is formed separately from the substrate on which the semiconductor laser element is mounted, and the photodetector is fixed to the substrate via the optical waveguide means. A material with good conductivity can be used. Accordingly, the heat dissipation of the semiconductor laser device can be improved.

Since the laser light emitted from the semiconductor laser element can be guided to the photodetector via the optical waveguide means, the output of the semiconductor laser element can be monitored by the photodetector without any trouble.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the semiconductor laser device of the present invention, FIG. 1 is a perspective view, FIG. 2 is a sectional view,
FIG. 3 is a perspective view showing a conventional example of a semiconductor laser device. Explanation of symbols 1... Good thermal conductive substrate, 2... Semiconductor laser element, 7... Photodetector, 10... Optical waveguide means. Cross-sectional view Figure 2

Claims (1)

[Claims] A semiconductor laser element is fixed on a part of the surface of a substrate with good thermal conductivity, and an optical waveguide guides monitor light from the semiconductor laser element onto another part of the surface of the substrate with good thermal conductivity. A semiconductor laser device characterized in that a photodetector is fixed via a means.