JPH05110197A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To lower the threshold value of a semiconductor laser having a quantum well in an active layer, and to make the efficiency and output of the semiconductor laser higher. CONSTITUTION:An active layer 13 is a (110)-direction multiple quantum well, composed of 5nm-thick AlGaAs layers of Al constitution 35% and 5nm-thick GaAs layers laminated by 5 periods. Besides, the active layer 13 has (001)-direction 4mum-wide ridge structure, and a (001)-direction waveguide path is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser,
In particular, the present invention relates to a semiconductor laser having a lower threshold, higher efficiency, and higher output.

[0002]

2. Description of the Related Art Conventionally, a quantum well laser having a quantum well formed in an active layer, which is a semiconductor laser having an in-plane waveguide, is disclosed in Japanese Journal of Applied Physics 2
6, (1987) L302, the active layer (0
Quantum wells of (01) direction or (111) direction are formed. In a quantum well laser having such a structure,
It is characterized in that the optical transition matrix element for TE waves in the active layer is 1.5 times as large as that of a semiconductor laser having no quantum well.

[0003]

However, in the semiconductor laser, it is desired to further reduce the threshold, increase the efficiency, and increase the output, that is, increase the optical transition matrix element. An object of the present invention is to provide a semiconductor laser having an optical transition matrix element larger than that of a semiconductor laser in which a quantum well of (001) direction or (111) direction is formed in an active layer.

[0004]

According to the present invention, in a semiconductor laser having a quantum well in an active layer, the quantum well is formed in a (001) direction and a (111) direction by a semiconductor having a zinc blende type crystal structure. A semiconductor laser having a quantum well in a predetermined direction other than that can be obtained.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. The semiconductor laser of this embodiment is GaAs (110).
On the substrate 11, Al _0.35 Ga _0.65 As n-type cladding layer 12 is 1 μm, GaAs / Al _0.35 Ga _0.65 As multiple quantum well active layer 13 is 0.05 μm, and Al _0.35 Ga _0.65.
The As p-type clad layer 14 and the GaAs cap layer 15 were sequentially grown to a thickness of 1 μm and 0.5 μm, respectively, by a metalorganic vapor phase epitaxy method. Here, the active layer 13 includes an AlGaAs layer having a film thickness of 5 nm and an Al composition of 35%, and a film thickness of 5 n.
It is a multiple quantum well in the (110) direction in which five m GaAs layers are stacked. In addition, the active layer 13 has a width of 4 μm [00
A ridge structure in the [1] direction is formed, and a waveguide in the [001] direction is formed. Further, in this semiconductor laser, Fabry-Perot resonators are formed by mirroring both end surfaces by reactive ion etching.

In the semiconductor laser having the above structure, [001]
The optical transition matrix element for the TE wave propagating in the direction is about 1.6 times that in the case where no quantum well is formed. That is, the threshold value of the semiconductor laser is further lowered, the efficiency is improved,
And it was possible to measure high output. The threshold current density, which is a device characteristic, was 160 A / cm ² .

In the above embodiment, the AlGaAs semiconductor laser has been described, but if the active layer is a semiconductor laser having a zincblende crystal structure semiconductor, Al
The present invention can be applied to a III-V group semiconductor laser or a II-IV group semiconductor laser such as a GaInP system and a GaInAsP system. Further, in the above embodiment, the waveguide is formed by forming the active layer into a ridge structure.
The waveguide may be formed by another method. Furthermore, although the Fabry-Perot type semiconductor laser has been described in the above embodiment, it may be a distributed feedback type semiconductor laser or a distributed reflection type semiconductor laser. Furthermore, although the semiconductor laser is manufactured on the n-type substrate in the above embodiment, a substrate having different polarities may be used.

[0008]

According to the present invention, in a semiconductor laser having a quantum well in an active layer, the quantum well is formed by a semiconductor having a zinc blende type crystal structure in the (001) direction and (11).
1) By using quantum wells in a predetermined direction excluding the direction,
It is possible to reduce the threshold value, increase the efficiency, and increase the output of the semiconductor laser.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

[Explanation of symbols]

11 GaAs (110) substrate 12 Al _0.35 Ga _0.65 As n-type cladding layer 13 GaAs / Al _0.35 Ga _0.65 As multiple quantum well active layer 14 Al _0.35 Ga _0.65 As p-type cladding layer 15 GaAs cap layer

Claims (4)

[Claims] 1. A semiconductor laser having a quantum well formed in an active layer, wherein the quantum well is a quantum well made of a semiconductor having a zinc blende type crystal structure and having a predetermined direction other than the (001) direction and the (111) direction. A semiconductor laser characterized in that 2. The semiconductor laser according to claim 1, wherein a waveguide is formed in the in-plane direction of the substrate that maximizes the oscillator strength of optical transition with respect to TE waves in the active layer. 3. The semiconductor laser according to claim 1, which is formed on a surface of a substrate in the predetermined direction. 4. The semiconductor laser according to claim 1, wherein the predetermined direction is a (110) direction.