JPH06101608B2 - Semiconductor laser device - Google Patents

Description

The present invention relates to a semiconductor laser device in which a plurality of semiconductor lasers are monolithically formed.

[Conventional technology]

We have disclosed in Japanese Patent Laid-Open Nos. 59-240418, 60-424, etc., a semiconductor device (hereinafter referred to as oblique array laser) that is monolithically formed and has a plurality of semiconductor lasers with different emission directions. Call).

In such an oblique array laser, when the angle formed by the radiation angles becomes large and the distance between them becomes narrow, the injection regions intersect as shown in FIG. That is, the cavity length Lc needs to be a certain length or more to cause laser oscillation, and is usually about 300 μm. Therefore, when the pitch is 20 μm, the injection regions overlap each other when the angle between them is 3 to 4 degrees or more.

SUMMARY OF THE INVENTION The present invention aims to provide a semiconductor laser device that can be easily manufactured, and can be combined with a lens or the like to form an optical system having a short optical path length. It increases the degree of freedom of.

The above-mentioned object of the present invention comprises a semiconductor layer laminated including an active layer, a pair of resonance surfaces formed in the semiconductor layer, and an electrode for supplying a current to the active layer, and a stripe is formed by supplying the current. In a semiconductor laser device in which a plurality of semiconductor laser elements, each of which emits laser light from the pair of resonance surfaces, is monolithically formed on the same substrate by causing laser oscillation in a light-emitting region The angle formed by the emission directions of the light is different between the one resonance surface side and the other resonance surface side, and the laser light is emitted from each element non-parallel to each other on at least one resonance surface side. As described above, it is achieved by forming the striped light emitting region by bending or bending.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an oblique array laser proposed in JP-A-59-240418. In the figure, 11 to 15 indicate individual semiconductor lasers, and 11a to 15a indicate the respective semiconductor lasers 11 to 15
Corresponds to the injection region of the electric current, that is, the emission region. The angles formed by the extension lines (hereinafter referred to as the resonance direction) 11b to 15b of the injection regions 11a to 15a and the normal line 18 standing on the resonance surfaces 16 and 17 are φa, φb, φc, φd, and φe, respectively. It is formed so that.

The resonance planes 16 and 17 are parallel to each other because a cleavage plane of a liquid crystal (eg, GaAs) normally used as a substrate is used. However, when the parallelism may be slightly different as in dry etching. Is based on the resonance surface 16 on the front side of the laser emission.

The light resonated at the resonance planes 16 and 17 is resonated as laser light.
When exiting from 16, it is bent according to Snell's law. In the figure, 11c to 15c indicate light emitting directions.

Here, if an angle formed by an arbitrary light emitting direction and the normal line 18, that is, an emitting angle is θ, a relationship of n / n ₀ = sin θ / sin φ is established. For example, considering the case of emitting light from a GaAs crystal,
Since n (refractive index of crystal) is about 3.5 and n0 (refractive index of air) is about 1, if φ is selected as 1 degree, the laser beam is emitted with an inclination of about 3.5 degree with respect to the normal line 18.

In the embodiment shown in FIG. 1, φa, φb, φc, φd, and φe are set to +1.0 degrees, +0.5 degrees, 0.0 degrees, −0.5 degrees, and −1.0 degrees, respectively. An array laser was produced in which θb, θc, θd, and θe were +3.5 degrees, +1.75 degrees, 0.0 degrees, −1.75 degrees, and −3.5 degrees, respectively.

FIG. 2-1 is an embodiment of the present invention. Reference numeral 21 is a monolithic oblique array laser device, 22 is a laser beam emission direction, 25 is a curved laser stripe portion, and 2 is a curved laser stripe portion.
Reference numerals 6 and 27 are mirror surfaces forming a laser cavity.

However, in the oblique array laser device, if the refractive index of the active layer at the laser end face is n ₁ and the angle between the laser stripe 25 and the normal 23 at the laser end face is θ ₁ , then θ ₁
In the case of 2sin ^-1 (1 / n ₂ ), it cannot be used in the embodiment of FIG. 2 because total reflection occurs at the end face of the laser.

An embodiment in this case is shown in FIG. In order to make the cavity surface almost perpendicular to the laser stripe, it is necessary to make it by etching, but because the laser stripe is curved, one surface 34 is formed by etching and the other surface 35 is opened. Can be created by Therefore, since the decrease in the reflectance due to the etching method of the mirror surface can be made only on one side, a good array laser device can be manufactured even when the radiation angle is large.

The curvature or the bending as in the embodiment of FIG. 2-2 can be arbitrarily set unless the curvature becomes extremely large. Further, if two lasers are taken as an example, it is possible to make a modification as shown in FIG. 2-3 in which the two lasers need not have the same shape.

Although individual laser structures are not mentioned, not only gain guide type lasers such as electrode stripes, but also index guided type lasers such as BH structure, ridge type and channel stripe type are generally applicable.

Needless to say, the material is generally applied to injection type lasers such as GaAs / AlGaAs type to Inp / InGaAsp type.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention provides an oblique array laser device which is integrated in a high density even if the emission angle of the laser light is large by bending or bending the stripe portion of the semiconductor laser light in the oblique array laser device. It has become possible.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of an oblique array laser, FIG. 2-1 is a view showing an embodiment of the present invention in which the laser stripe portion is curved, FIGS. 2-2, 2-3 and FIG. 3 is a view showing a modified example of the present invention, and FIG. 4 is a plan view showing a case where stripe portions intersect. 11 to 15 …… Semiconductor laser, 16,17 …… Resonance plane.

Front page continuation (72) Inventor Mitsutoshi Hasegawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Seiichi Miyazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-52-120991 (JP, A) JP-A-62-162385 (JP, A)

Claims (1)

[Claims] 1. A stripe-shaped semiconductor layer comprising an active layer, a pair of resonance planes formed on the semiconductor layer, and an electrode for supplying a current to the active layer. In a semiconductor laser device in which laser oscillation is generated in the light emission region and a plurality of semiconductor laser elements each emitting laser light from the pair of resonance surfaces are formed monolithically on the same substrate, the laser light emitted from each element is The angles formed by the emission directions are different on the one resonance surface side and the other resonance surface side, and at least one resonance surface side emits laser light non-parallel to each other. In the semiconductor laser device, the light emitting region having a stripe shape is curved or bent.