SEMICONDUCTOR LASER HAVING IMPROVED FACETS OF THE RESONATOR

Abstract

In a semiconductor laser having a first facet (front facet) through which laser light is emitted and a second facet (rear facet), and a first coating film composed of a single-layer dielectric film on the first facet. The oscillating wavelength of the laser light is λ and the refractive index of the dielectric film is n. The thickness of the dielectric film is within a range between 5% and 50% of λ/4n.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a perspective view of a semiconductor laser; and

FIG. 2 shows the rates of defects of the semiconductor lasers.

Claims

1. A semiconductor laser comprising: a resonator disposed along a traveling direction of a laser beam;a first facet at a first end portion of said resonator, from which the laser beam is emitted; anda second facet at a second end portion of said resonator, wherein a first coating film consisting of a single layer dielectric film coats at least one of the said first facet and said second facet, andthe oscillating wavelength of the laser beam is λ and the refractive index of said dielectric film is n, and the thickness of said dielectric film is within a range between 5% and 50% of λ/4n.

2. The semiconductor laser according to claim 1, wherein said first coating film coats said first facet, anda second coating film having a higher reflectivity than said first coating film coats said second facet.

3. The semiconductor laser according to claim 1, wherein said semiconductor laser is a gallium nitride semiconductor laser that generates blue laser light.

4. The semiconductor laser according to claim 2, wherein said semiconductor laser is a gallium nitride semiconductor laser that generates blue laser light.

5. The semiconductor laser according to claim 1, wherein the thickness of said dielectric film is within a range between 5% and 20% of λ/4n.

6. The semiconductor laser according to claim 1, wherein said dielectric film is composed of a material selected from the group consisting of aluminum nitride, amorphous silicon, aluminum oxide, titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, silicon oxide, and hafnium oxide.

7. The semiconductor laser according to claim 1, wherein said dielectric film is formed using any one of vapor deposition, sputtering and chemical vapor deposition.

8. The semiconductor laser according to claim 1, wherein said dielectric film is composed of two elements A and B; andthe energy required to dissociate a diatomic molecule A-B composed of the elements A and B into A and B is larger than the energy required to dissociate a diatomic molecule Al—O composed of Al and O into Al and O.

9. The semiconductor laser according to claim 8, wherein the element A is selected from the group consisting of titanium, niobium, zirconium, tantalum, silicon, and hafnium; andthe element B is oxygen.