JPH02214182A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To prevent interference of laser light and occurrence of recesses and projections of far-field pattern in horizontal direction by providing an absorption layer on a cleavage edge surface and by taking out the light which is irradiated vertically from the edge surface of the cleavage selectively as laser light. CONSTITUTION:An absorption layer of light is provided in slit shape on a cleavage edge surface 13 which is a resonator surface. That is, after applying a positive resist 5 onto the cleavage edge surface 13, a sensitized agent 14 is applied to the surface of the resist 5. Then, a power supply is connected to electrodes 1 and 8 for achieving laser oscillation, exposure is made by light which is irradiated vertically from the cleavage surface 13, an exposed part 15 is removed by development, and then the positive resist 5 is used as the absorption layer. Therefore, light irradiated from the side surface of a stripe 10 is eliminated by this absorption layer in laser oscillation and laser light is irradiated vertically from the cleavage edge surface 13. Thus, it becomes possible to prevent occurrence of recesses and projections due to interference in the far-field pattern in horizontal direction.

Description

[Detailed description of the invention] “Industrial Application Field 1 The present invention relates to a semiconductor laser device.

[Prior art 1 Fig. 2 (8) shows the conventional WDS (Winclow
FIG. 2(b) is an exploded perspective view showing the structure of a Diff'fusian Stripe type semiconductor laser device, and FIG. Figure 2 (
c) is a far-field pattern diagram of the semiconductor laser in the horizontal direction.

In the figure, (1) is an electrode, (2) is a mouth-type GaAs contact layer, (3) is an n-type Ga 1-xAlxAs stopper layer% (4) is n! J Ga 1-yA1yAa washed layer, (5) is n 5 Ga+-zAlzAs active layer, (6) is! 1 type Ga l-yAlyAs cladding layer, σ) is n type Ga As substrate, (8) is t pole, (9)
is a P-type Zo diffusion region, (10) is a stripe region, (1
1) shows the laser light emitted from the arm opening surface, and (12) shows the light emitted from the striped surface.Next, the movement will be explained. It has not spread the P-type C expansion area (9), which has spread the following (4) (5) (6)
(7) An h-junction is formed between each layer and the n-region of the substrate. Therefore, when a forward voltage is applied between the electrodes (1) and (8), a current flows in the stripe region (10), carriers are confined, and recombination light emission occurs. The light is transmitted to the cladding layers (4), (6) and the stripe area (10).
In the measurement surface, light is guided in a waveguide with a refractive index difference due to the concentration of P-type and n-type impurities, and laser oscillation occurs in a resonator formed by opposing extended end surfaces. )) shows a schematic diagram of laser light emission in this stripe region. The laser light (11) is emitted perpendicularly to the extended end face, and the laser light escapes from the irregularities of the stripe surface beyond the critical angle of total reflection to the outside of the stripe. Light (12) is generated.

[Problem to be solved by the invention 1 Since the conventional WDS semiconductor laser device was configured as described above, the laser beam (11) is caused to interfere with the light (12), and the laser beam (12) is As shown, there was a problem in that unevenness was created in the far field pattern in the horizontal direction.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a semiconductor laser device in which a horizontal far-field pattern has no unevenness.

[Means for Solving the Problems j] In the WDS semiconductor laser device according to the present invention, after applying a positive resist to the expanded end face, a photosensitive agent is further applied to the resist surface, and then a power source is connected to the electrode of the semiconductor laser to perform laser oscillation. and expose the subject to light emitted perpendicularly from the open surface of the arm.

Next, the exposed portion is removed by development, and the positive resist is used as it is as an absorption layer. During laser oscillation, the light emitted from the striped surface is removed by this absorption layer, and the laser light is only emitted perpendicularly from the extended end surface.

[Function 1] The positive resist of the stretched end face in this invention absorbs the light emitted from the striped surface in its layer, and from the interosseous end face of the laser, only the light emitted perpendicularly from the arm opening face is produced, so that the horizontal direction of the resist is reduced. The field pattern can prevent the occurrence of unevenness due to interference.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
Figures (a) to (e) are diagrams showing the manufacturing process of an embodiment of the present invention, where (a) is an open end view of the arm from which light is emitted, and (b)
(a) A figure with positive molding and application of dinut on the surface of the figure, (C
) is (b) a diagram showing the photosensitive agent applied on the drawing, (d) is a diagram showing the state in which a power supply is connected to the electrode, laser oscillation is caused, and the exposed area is exposed to laser light. (e) is the diagram showing the exposed area after development. remove the
A diagram using a positive resist as an absorption layer is shown.

In the figure, (1) and (8) are electrodes, (5) is a resist, (10) is a stripe, (13) is a resonator end face, and (1) is a stripe.
4) is a photosensitizer, (15) is a portion exposed to laser light, (
16) shows the resist removed portion.

Next, the operation will be explained.

The operation of this embodiment is the same as that of the conventional one, except that during laser oscillation, the light emitted from the stripe surface is removed by an absorption layer provided on the cleavage end surface, and the light emitted from the stripe surface is removed by the absorption layer provided on the cleavage end surface. Since there is no absorption layer, the emitted light can be emitted as is. Therefore, a far-field pattern in the horizontal direction can be obtained without unevenness due to light interference.

In the Queen's embodiment, the case of a WD8 semiconductor laser device, which is a refractive index waveguide laser, has been described, but since the semiconductor laser device according to the present invention has an absorption layer on the cleaved end facet, other semiconductor laser devices, e.g. TJ8
(Transerense, Twnction 5t
It is also possible to apply the present invention to semiconductor laser devices such as lasers.

Further, in the above embodiment, a case was shown in which a positive resist was used as the absorbing layer, but it is also possible to use a layer other than the resist as the absorbing layer by using a negative resist.

[Effect of the invention 1 As described above, according to the present invention, an absorption layer is provided on the cleaved end face of the semiconductor laser, and only the light emitted perpendicularly from the extended end face is selectively extracted as laser light.
It has the advantage that there is no interference between laser beams, no unevenness in the far field pattern in the horizontal direction, and therefore tracking control can be easily performed when used as a CD laser.

[Brief explanation of the drawing]

FIGS. 1(a) to (e) are surface views showing the manufacturing process of a semiconductor laser device according to an embodiment of the present invention, FIG. 2(a) is an exploded perspective view showing the structure of a conventional WD8 semiconductor laser, FIG. 2(b) is an explanatory diagram showing the state of the laser beam in the stripe area of FIG. 2(a), and FIG. 2(c) is the horizontal far-field pattern of the laser beam of FIG. 2(b). FIG. In the figure, (1) (8) is an electrode, (5) is a resist, (10) is a stripe, (13) #i resonator end face,
In (14), the photosensitizer (15) is the part exposed to laser light;
(16) shows the resist removed portion. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A light absorption layer is provided in the form of a slit on the cleaved end face, which is the resonator face of the semiconductor laser. During laser oscillation, the light that is emitted perpendicularly from the resonator end face is emitted through the slit, and the waveguide is 1. A semiconductor laser device characterized in that light exceeding a total reflection threshold from a measured surface is absorbed by an absorption layer.