JPH06204602A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To improve optical output characteristics by enhancing the heat- dissipating performance of a semiconductor laser. CONSTITUTION:A reflecting or nonreflecting film formed onto the end face of a laser element 1 is shaped in a partial region containing the light-emitting end face 2 of an active layer. Accordingly, heat-dissipating performance is made better than the formed film 4 is formed extending over all regions of the end faces of the laser element 1, and the output power of a semiconductor laser is increased, thus improving the reliability of beam output driving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser which outputs a laser beam.

[0002]

2. Description of the Related Art Semiconductor lasers are widely used as a light source for optical communication. In a general semiconductor laser of this type, as shown in FIG. 6, a light emitting end surface 2 of an active layer is exposed on an end surface of a laser element 1, and electrodes 3 are formed on both upper and lower sides of the laser element 1. There is. In this semiconductor laser, when a driving voltage is applied between the electrodes 3, the light energy confined in the active layer is activated by a current flowing intensively in the active layer, and this active light energy causes a threshold value. When it exceeds, the laser beam is output from the light emitting end face 2.

Generally, a film 4 of a reflective film or a non-reflective film is formed on the end face side of this type of semiconductor laser in order to improve characteristics such as reduction of the oscillation threshold current over the entire region. Has been done.

These film formations 4 are composed of a dielectric layer such as silicon nitride, aluminum oxide, silicon oxide, amorphous silicon, or a multilayer film thereof, and normally, as shown in FIG. PC holding element 1
It was formed by growing the film forming material 8 on the entire end face of the laser element 1 by means of VD, electron beam evaporation, sputtering or the like.

[0005]

However, the method of forming the film formation 4 over the entire region of the end face of the laser element 1 is such that the film forming material, during the film forming operation, is on the side orthogonal to the end face to be formed. Since it goes around to the electrode 3 side, the film-forming material adheres to the electrode 3 as well, which lowers the heat dissipation performance of the semiconductor laser, raises the temperature of the laser element 1 during the operation of the semiconductor laser, and There is a problem that it causes a decrease, an increase in threshold current and a decrease in reliability as a light source.
Of course, the film-forming material attached to the electrode 3 can be removed by etching or the like, but it is difficult to completely remove it.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is a semiconductor in which a film formed on an end face of a laser element does not adhere to an electrode side to deteriorate heat dissipation performance. To provide a laser.

[0007]

In order to achieve the above object, the present invention is constructed as follows. That is, the present invention is a semiconductor laser in which a reflective film or a non-reflective film is formed on an end surface of a laser element where an end surface of an active layer that emits a laser beam is exposed. It is characterized in that it is formed only in the local region including the active layer.

[0008]

In the present invention having the above structure, the reflection film (or non-reflection film) formed on the end face of the laser element is formed only in the local region including the end face of the active layer, so that the heat dissipation characteristics of the semiconductor laser are improved. As a result, the temperature of the laser element can be kept low, and highly reliable output driving of the laser beam becomes possible.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same parts as those in the conventional example are designated by the same reference numerals, and the duplicate description thereof will be omitted. FIG. 1 shows a first embodiment of the semiconductor laser according to the present invention. The feature of this embodiment is that the film 4 of the non-reflective film is formed on the end face of the laser element 1 only in the local region including the light emitting end face 2 of the active layer. This film formation 4 can be formed by various film forming means using the same film forming material as in the conventional example, but in this example, a PCVD apparatus is used to form a light emitting end face 2 of the active layer and a peripheral region thereof. The film is formed only in the area of 100 μm square. As a result, the length L of the unnecessary adhesion film that has wrapped around the electrode 3 side and adhered is about 10
With the width of 0 μm and the width W of about 20 μm, the area of the attached film attached to the electrode 3 was extremely small, and the heat dissipation characteristics of the semiconductor laser could be significantly improved as compared with the conventional example. When the light output characteristics of the semiconductor laser of this example were examined, it was found that the heat radiation characteristics were improved.
It was possible to confirm the increase of the optical output power of%. Further, it is possible to provide a highly reliable semiconductor laser with almost no increase in threshold current.

FIG. 2 shows a second semiconductor laser according to the present invention.
Examples of are shown. In this embodiment, the formation region of the film 4 of the antireflection film is made smaller than that in the first embodiment, and the antireflection film is formed so as not to cover the electrode 3 side. As described above, the heat radiation performance of the semiconductor laser is further improved by making the formation area of the non-reflection film 4 smaller, and the temperature rise of the laser element 1 is further suppressed as compared with the case of the first embodiment. This makes it possible to prevent the threshold current from increasing, and further improve the optical output characteristics and reliability.

3 to 5 show a manufacturing example in which a film 4 of a non-reflective film is formed on the end face of the laser element 1. In the structure shown in FIG. 3, a mask 5 made of an appropriate material such as metal or glass is provided with a film formation hole 6 having a size surrounding a local region including the light emitting end face 2, and the film formation hole 6 is formed. The mask 5 is applied to the end surface of the laser element 1 in alignment with the light emitting end surface 2 of the active layer, and in this state, a film forming material is formed from above the mask 5 by means of the PCVD or the like to form a film. Forming a non-reflective film of a size corresponding to the hole 6 4
Are formed at local positions on the end face of the laser element 1.

FIG. 4 shows, for example, a laser device 1.
Two pieces of a and 1b are set to each other by using a jig or the like, and a film forming hole 6 having a size across the light emitting end face 2 of the optical fiber active layer of each laser element 1a and 1b is provided on the mask 5 side. The film forming hole 6 is positioned so as to straddle the light emitting end faces 2 of the laser elements 1a and 1b so that both of the light emitting end faces 2 fit within the holes. By growing the antireflection film from the upper side, the laser element 1a,
The film formation 4 is simultaneously formed in the local region of the end surface 1b.

In FIG. 5, a plurality of laser elements 1 are assembled and set, and each light emitting end face 2 is provided on the mask 5 side.
By forming a plurality of film formation holes 6 at positions corresponding to the above, and forming a non-reflective film from the upper side of the mask 5 with each film formation hole 6 aligned with the corresponding light emitting end face 2. The film formation 4 is intended to be formed at one time in the local region including the light emitting end faces 2 of the plurality of laser elements 1.
In addition, the film formation 4 can be formed by various methods other than the above.

The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, in each of the above embodiments, the non-reflective film is formed as the film formation 4 in the local region including the light emitting end face 2, but unlike this, the reflection film may be formed as the film formation 4.

[0015]

According to the present invention, since the reflective film or the non-reflective film is formed only in the local region including the light emitting end face of the photoactive layer among the end faces of the laser element, the semiconductor laser is formed. The heat dissipation characteristics of can be greatly improved. As a result, the temperature rise during driving of the semiconductor laser can be reduced, so that the increase in threshold current can be suppressed, the output characteristics of the laser element can be improved, and the reliability of element driving can be improved.

[Brief description of drawings]

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

FIG. 2 is a structural explanatory view showing a second embodiment of the present invention.

FIG. 3 is an explanatory view showing an example of forming a reflective film (or a non-reflective film).

FIG. 4 is an explanatory diagram of another method of a film forming example of a reflective film (or a non-reflective film).

FIG. 5 is an explanatory diagram of still another method of forming a film of a reflective film (or a non-reflective film).

FIG. 6 is an explanatory diagram of a conventional semiconductor laser.

FIG. 7 is an explanatory diagram of an example of forming a reflective film (or a non-reflective film) in a conventional semiconductor laser.

[Explanation of symbols]

 1, 1a, 1b Laser element 2 Light emitting end face 3 Electrode 4 Film formation 5 Mask 6 Film formation hole

Claims (1)

[Claims] 1. A semiconductor laser in which a reflective film or a non-reflective film is formed on an end surface of a laser element where an end surface of an active layer for emitting a laser beam is exposed, wherein the reflective film or the non-reflective film is formed on the end surface of the laser element. A semiconductor laser characterized in that it is formed only in a local region including the active layer.