JPH01161794A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To obtain a device capable of emitting in single mode, widening the emission area, and high output operation, by forming a refractive index distribution and gain distribution in the transverse direction of a wide ridge and composing so as to form a plurality of lasers adjacent to the ridge. CONSTITUTION:A semiconductor laser device comprises a semiconductor substrate 1, on which a semiconductor active layer 3, first and second semiconductor clad layers 2 and 4 mounted adjacent to and having a wider forbidden band than said active layer 3, and a third semiconductor blocking layer S having a wider forbidden band than and of a different conduction type from, and mounted on said second semiconductor clad layer 4 having a striped-looking ridge 16 of 10mum or more width are installed at least. A plurality of gain waveguide paths are formed on the ridge 18 by forming a plurality of striped- looking mesa-shaped grooves on the third semiconductor blocking layer 5 on the ridge 16, for example a n-type AlGaAs blocking layer 5 having two mesa- shaped grooves formed on a p-type AlGaAs upper clad layer 4 having an about 15mum wide ridge 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a semiconductor laser device that uses hydrofluoric acid in a single transverse mode and operates at high output.

[Conventional technology]

Figure 3 shows, for example, "HLgh-power single
1orH1tud-insl mode op
ration of 1inverted cha
nnel 5ub-strate planet 1
asers” J, J, Yang+ C-3*HOng
+J-Nieaen+ and L, Figuero
a-J, Appl, Phys・58 (IILI Dec
1985, p-4480-4482; FIG.
In the figure, (11[n-type GaAs substrate, (Ill 1
4 n-type G5As buffer layer, (2) is n-type AjGaA
s lower cladding layer, Q2) ij GaAa active layer, 14
11q P-type A with striped ridge (I)
IG a As lower cladding layer, (I4) is p-deca Ga
A@layer, α (to) is the upper cladding layer (4) and p-decade GaA
An n-type GaA m block layer formed to bury the s layer (14), a zn diffusion region formed in the ridge part of the θ51 hub block layer so as to reach the upper cladding layer (4),
(7) is an n-side electrode, and (8) is a p-side electrode.

Next, the operation will be explained. When a forward bias voltage of the pn junction is applied between the p-side electrode (7) and the n-side electrode (8), a current flows through the Zn diffusion region [(15)t- of the threshold part to the active layer (I2). These injected carriers are confined within the active layer a2 by the barrier at the heterojunction interface, recombine, and emit light.

Furthermore, a refractive index difference occurs in the horizontal direction (lateral direction) in the active layer 02 due to light absorption and current confinement in the current blocking layer 0□□□, which limits the spread of light in the lateral direction and stabilizes the transverse mode. becomes.

The light guided by such a waveguide (Fabry-Perot (Fabry-Perot) is formed by the end faces between the opposing folds perpendicular to the depth direction of the striped ridge.
[Problems to be solved by the invention] Since the conventional semiconductor laser device is configured as described above, in order to oscillate in a single transverse mode, it is necessary to The stripe width of the part must be narrowed to 3 to 5 μm, which causes problems such as the narrowing of the light emitting area and the difficulty of high output operation.

This 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 that is capable of single mode oscillation, has a wide light emitting region, and is capable of high output operation.

[Means for solving problems]

A semiconductor laser device according to the present invention is configured such that a refractive index distribution and a gain distribution are formed in the lateral direction of a wide ridge portion, and a plurality of lasers are formed adjacent to the ridge portion.

[Effect]

In the semiconductor laser according to the present invention, a plurality of lasers are formed close to each other in the ridge portion, so that phase synchronization occurs. Furthermore, in the gain waveguide section, the refractive index decreases during current injection, resulting in anti-guiding and a single transverse mode is generated. Furthermore, the light emission flJ[ becomes wider and high output operation is possible.

〔Example〕

Hereinafter, this invention will be explained using figures. FIG. 1 is a cross-sectional perspective view showing a semiconductor device according to an embodiment of the present invention. In the figure, 11+ is about 10 (n of Lllrn thickness
(2) n-type A4GaA with a crystal thickness of about 2μ
s (AL11A composition ratio x=0-4) lower cladding layer, (
3) Active layer of about 0.1 pm ALGaAs (A1. @ acid ratio
Forms a lateral ridge α with a width of voice m, and has a convex portion of about 2. ttm thickness,
After the concave portion was formed so as to eat into the upper cladding layer of p-type AJGaAs (Aj composition ratio x = 0.4) with a thickness of about 0.5 mm, (5) and the upper cladding layer (4) in which the ridge was formed,
N-type AjGaAs (A
A block layer with L m acid ratio
A contact layer of p-type GaAa with a thickness of pm, an n-side electrode at (7), and a p-side electrode at (8).

In addition, each layer 121 to tel i is MOCVD (
Metal Or-ganlc Chemical V
apor DeposIt4on) method and MBE (M
olsculer Beam F, pitaxial
) vapor phase growth method such as ij LPE (Liqu
It is formed by any liquid phase growth method such as id Phase Epitaxial method.

Next, the operation will be explained. The operating mechanism of this semiconductor laser device is almost the same as that of a conventional semiconductor laser device.

By providing two (or more than one) gain sieving wave stripes on the wide ridge (16), the gain distribution and refractive index distribution make it appear as if there are two (or several nD) stripes on the ridge.
Since the semiconductor lasers are formed close to each other, they are phase synchronized. Furthermore, in the gain waveguide section, when current is injected, the refractive index decreases and a reciprocal wave is generated, higher-order modes are cut off, single transverse mode oscillation occurs, and the light emitting region is wide, so high output operation is possible.

Since the portions other than the ridge hardly participate in transverse mode control, there is no need for strict control in etching when forming the ridge, and manufacturing is easy.

In addition, since the block layer is an n-type ALGaAs layer with a wider forbidden band width than the upper cladding layer, an English refractive index distribution occurs in the lateral direction in the ridge and the outside of the ridge, making it possible to efficiently confine light inside the ridge. This improves the luminous efficiency.

In addition, in the above example, two striped mesa-shaped Ss were formed on the ridge Q6), but three grooves were formed on the ridge Q6).
or more. Furthermore, in the above embodiment, the case where the contact layer 161 was formed on the upper cladding 1 (4) and the block layer (5) having a large pAL composition ratio was explained.
! As shown in Fig. 32, in order to avoid the problem of regrowth interface, the ridge part α■ of the upper cladding layer (4) and the block layer (5
) on each thin (less than 0.1 pm) undoped G
An aAs layer (91) and an n-type GaAa l11 (101) may be provided, and the same effect as in the above embodiment can be obtained. The portion in contact with the contact layer (61) becomes p-type. Also, when etching the block layer (5), selective etching becomes possible and groove formation becomes easy.

〔Effect of the invention〕

As described above, according to the present invention, a refractive index distribution and a gain distribution are formed in the lateral direction on a wide ridge portion, and a plurality of semiconductor lasers are formed close to each other on the ridge, so that oscillation It has the effect of being able to operate over a wide range of areas and at high output, as well as being able to fire in a single structure mode.

[Brief explanation of the drawing]

FIG. 1 is a perspective sectional view showing a semiconductor laser device according to an embodiment of the present invention, FIG. 2 is a perspective sectional view showing another embodiment of the invention, and FIG. 3 is a perspective sectional view showing a conventional semiconductor laser device. It is a diagram. In the figure, l1llln type GaA@substrate, f21Un
Type A1GaAa lower cladding layer, (31U AjGsAs
active layer, (4) is p-type AJGaAs upper cladding layer,
(511dn type AJGaAs block layer, 16)It
'l p -GaA@contact layer, (7) 16 n-side electrode, f81 r; c p (lIJ 1! pole, +91
1-1 and loop GaAs layer, (Sol Lrl n-type GaAs layer, 06 is p layer with striped ridges formed)
- AjGaAs upper cladding layer. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) At least a semiconductor active layer on a semiconductor substrate, a first semiconductor layer adjacent to the active layer and having a larger forbidden band width than the active layer;
A third semiconductor block layer is formed on the second semiconductor cladding layer and the second semiconductor cladding layer having a striped ridge with a width of 10 μm or more and has a larger forbidden band width than the second semiconductor cladding layer and a different conductivity type. A semiconductor laser device characterized in that a plurality of gain waveguides are formed on the ridge by forming a plurality of striped mesa-shaped grooves in the third semiconductor block layer on the ridge. laser equipment. (2) An undoped fourth semiconductor layer with less surface oxidation than the second cladding layer on the second semiconductor cladding layer on the ridge, and a third block having the same conductivity type as the block layer on the third semiconductor block layer. The fifth layer has less surface oxidation than the
2. The semiconductor laser device according to claim 1, wherein each of the semiconductor layers is formed thinly. (3) The active layer is made of Al_xGa_1_-_xAs, the Al composition ratio is 0≦x≦0.2, the Al composition ratio of the first and second cladding layers is 0.3≦x≦0.5, and the third block is 3. The semiconductor laser device according to claim 1, wherein the Al composition ratio of the layer is 0.6 or more, and the fourth and fifth semiconductor layers are made of GaAs. (4) The semiconductor laser device according to claims 1 and 2, wherein an AlGaInP or InGaAsP quaternary mixed crystal is used for the active layer as the semiconductor material.