JPH0294687A - Mask semiconductor laser - Google Patents

Abstract

PURPOSE:To eliminate a trouble of residue at a conventional formation of a projection hole through evaporation and to improve durability of the projection area by making a light-screening mask layer transparent to form a pin-hole projection area. CONSTITUTION:A transparent insulating layer 2A is formed at a light projection edge side of a semiconductor laser, and a light screening mask layer 3 is further formed on the layer 2A. In a mask semiconductor laser wherein a pin-hole projection area 4 is formed by making a semiconductor laser light emitting section at a mask layer 3 transparent through light emission of the semiconductor laser itself, Cr is used as a material of the mask. That is, the mask layer 3 using Cr is made transparent in a shape of pin-hole through a laser hole from a semiconductor laser. According to this constitution, a problem of residue can be eliminated different from the case of projection hole formation by evaporation of a mask layer and the projection area 4 can be formed even under a normal pressure.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mask semiconductor laser.

[Prior Art] The inventors have proposed various mask semiconductor lasers.

A mask semiconductor laser is a masked semiconductor laser in which a light-shielding mask layer is provided on the light emitting end face of the semiconductor laser, a pinhole-shaped light passage part is provided in a part of this mask layer, and the laser beam from the semiconductor laser is emitted from the pinhole-shaped emission hole. can be taken out, and can be used as a substantial point light source.

[Problems to be Solved by the Invention] Conventionally proposed masked semiconductor lasers include forming a light-shielding mask layer on the light-emitting end face of the semiconductor laser by vapor deposition, etc. The injection hole is formed by evaporating and removing a part of the mask layer to form a pinhole-shaped injection hole.As mentioned above, the injection hole is formed by evaporating and removing a part of the mask layer. There was a problem in that residue remained on the edges of the injection hole, and the shape of the injection hole could not be perfectly circular, and there was also a problem in terms of durability.

The present invention has been made in view of the above-mentioned circumstances, and
The purpose is to provide a novel mask semiconductor laser that is free from the problems caused by the above-mentioned residues and has excellent durability.

[Means to solve the problem] The present invention will be explained below.

In the mask semiconductor laser of the present invention, a transparent insulating layer is formed on the light emitting end face of the semiconductor laser, a light-blocking mask layer is further formed on the transparent insulating layer, and the semiconductor laser in the mask layer is caused to emit light from the semiconductor laser itself. This is a mask semiconductor laser in which a laser emitting part is made transparent to form a pinhole-shaped emission part, and is characterized in that Cr is used as the material of the mask.

Although it is possible to make the mask layer transparent using Cr under normal pressure, pinhole-shaped injection parts can be formed with a smaller injection current under reduced pressure of 10-'' Torr or less.

The semiconductor laser is not particularly limited and various types can be used, but among commercially available ones, AlGaAs ternary semiconductor lasers with wavelengths of 780 na+ and 830 nm are suitable.

A thin film of SiO, 5iO1ysiN, etc. is used as the transparent insulating layer formed directly on the light emitting end face of the semiconductor laser. Here, it goes without saying that the insulating layer is transparent means that the insulating layer is transparent to laser light emitted from the semiconductor laser on which the transparent insulating layer is formed.

[Function] As described above, the mask semiconductor laser of the present invention is produced by making a mask layer using Cr transparent in the form of pinholes with laser light from a semiconductor laser.

Therefore, unlike the case where the injection holes are formed by evaporation of the mask layer, there is no problem of residue generation, and the injection portion can be formed even under normal pressure.

[Example] Hereinafter, description will be given based on specific examples.

Referring to the drawings, reference numeral l in the drawings indicates a mask semiconductor laser, and this mask semiconductor laser 1 consists of a semiconductor laser 2, a transparent insulating layer 2A, a mask layer 3, and a pinhole-like structure formed in the mask layer 3. and an injection section 4.

Example 1 A GaAlAs double hetero type semiconductor laser 2 with a maximum rated output of 5 mW, an oscillation wavelength of 780 nm, and a maximum operating current of 100 mA was used as the semiconductor laser 2. A thin film of SiN was used as a transparent insulator/12A on the light emitting end face of the semiconductor laser 2. 1
Coated to a thickness of 72 mm.

On this transparent insulating layer 2A, 1026 thin films of Cr were formed by vacuum evaporation to form a mask M3.

The vapor deposition conditions are as follows.

Vapor deposition material: Cr, Vapor deposition temperature: 1800°C9 Vapor deposition source boat: Tungsten, Vacuum degree: IX 1O-5To
rr Then, the semiconductor laser was made to emit light. This laser light passes through the transparent insulating layer 2A and irradiates the mask layer 3 from the inside, making the mask layer 3 transparent in the form of pinholes.

If a power meter is installed on the emission end face of the semiconductor laser to monitor the output of the semiconductor laser, the output will gradually increase as the pinhole-shaped emission part is formed.Use this fact to determine the formation of the emission part. to judge.

As a result, the threshold current 51. : At 44 mA, a mask semiconductor laser was obtained in which a pinhole-like emission part of about 2 μm was formed.

When the above-mentioned emission part was observed with an optical microscope, it was confirmed that a transparent part with a black edge of 2 μm and a pale blue center was formed directly above the light-emitting part of the semiconductor laser.

Further, even when the injection current was increased to the maximum value of the rated operating current, no change was observed in the diameter or shape of the pinhole-shaped injection part.

Example 2 A thin film of SjN was coated as a transparent insulating layer 2A on the light emitting end face of a semiconductor laser of the same type as in Example 1.
A thin film of Cr was formed on the mask layer 3 under the same conditions as in Example 1 to form a mask layer 3.
And so.

A mask semiconductor laser was obtained by forming a pinhole-shaped emission part in the same manner as in Example 1, and when observed with an optical microscope, it was confirmed that a transparent emission part with a diameter of about 1.2 μm was formed.

Example 3 A thin film of SiN was coated as a transparent insulating layer 2A on the light emitting end face of a semiconductor laser of the same type as in Example 1, with the oscillation wavelength being 1/2 of the above-mentioned oscillation wavelength.
A thin film of 1,570 Cr was formed thereon under the same conditions as in Example 1 to form a mask layer 3.

A pinhole-shaped injection portion was formed in the same manner as in Example 1 to obtain a mask semiconductor laser.

Upon inspection with an optical microscope, it was confirmed that a transparent injection part with a diameter of about 1.2 μm was formed.

Example 4 A thin film of SiN was coated as a transparent insulating layer 2A on the light emitting end face of a semiconductor laser of the same type as in Example 1, with the oscillation wavelength being 1/2 of the above oscillation wavelength.
A thin film of 1880 Cr was formed thereon under the same conditions as in Example 1 to form a mask layer 3.

A pinhole-shaped injection portion was formed in the same manner as in Example 1 to obtain a mask semiconductor laser.

When observed with an optical microscope, it was confirmed that a transparent injection part with a diameter of about 1 μm was formed.

In all of the mask semiconductor lasers of Examples 1 to 4, there was no change in the diameter and shape of the injection part within the rated operating current range.

[Effects of the Invention] As described above, according to the present invention, a novel mask semiconductor laser can be provided.

As mentioned above, in this mask semiconductor laser, a pinhole-shaped emission part is formed by making the Cr light-shielding mask layer transparent, so there is the problem of residue, which was a problem when forming an injection hole by conventional evaporation. There is no.

The injection part also has excellent durability.

[Brief explanation of drawings]

The figure is a diagram for explaining a mask semiconductor laser.

Claims (1)

[Claims] A transparent insulating layer and a light-shielding mask layer are laminated in the above order on the light emitting end surface of a semiconductor laser, and the semiconductor laser light emitting portion in the mask layer is emitted by the semiconductor laser itself. What is claimed is: 1. A mask semiconductor laser comprising a pinhole-shaped emission portion formed by making the portion transparent, the mask semiconductor laser characterized in that Cr is used as a material for the mask layer.