Semiconductor laser device

• US 20040213314A1
• Filed: 04/21/2004
• Published: 10/28/2004
• Est. Priority Date: 04/23/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakagawa, Yasuyuki, Nishiguchi, Harumi, Kunitsugu, Yasuhiro, Matsuoka, Hiromasu
• Granted Patent: US 7,039,085 B2
• Time in Patent Office: Days
• US Class Current: 372/49
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/0287 Facet reflectivity

Abstract

A semiconductor laser device includes a dielectric multilayer film with a reflectance of 40% or more, on at least one of optical exit faces of a laser chip. The dielectric multilayer film includes a film of tantalum oxide (Ta₂O₅) and another film of a dielectric oxide, such as aluminum oxide (Al₂O₃), and silicon oxide (SiO₂). The tantalum oxide film has an optical absorption coefficient smaller than that of silicon (Si) and thermal stability in emission superior to that of titanium oxide (TiO₂) thereby remarkably improving the catastrophic optical damage degradation level of the laser chip.

Claims

1. A semiconductor laser device comprising a dielectric multilayer film with a reflectance of at least 40% on at least one of optical exit faces of a laser chip, wherein the dielectric multilayer film includes a film of tantalum oxide.

2. The semiconductor laser device according to claim 1, wherein the dielectric multilayer film includes a film of aluminum oxide and the film of tantalum oxide.

3. The semiconductor laser device according to claim 1, wherein the dielectric multilayer film includes a film of aluminum oxide in contact with the laser chip, and film of silicon oxide and the film of tantalum oxide.

4. The semiconductor laser device according to claim 2, wherein the dielectric multilayer film is configured of a total of nine layers of, in sequence from the side in contact with the laser chip, an aluminum oxide film, a tantalum oxide film, an aluminum oxide film, a tantalum oxide film, an aluminum oxide film, a tantalum oxide film, an aluminum oxide film, a tantalum oxide film, and an aluminum oxide film.

5. The semiconductor laser device according to claim 4, wherein each of the first to eighth layers, from the side in contact with the laser chip, has a thickness equivalent to λ

/4 in terms of optical lengths at an oscillation wavelength λ

of the laser chip, and the ninth layer has a thickness equivalent to λ

/2 in terms of optical length.

6. The semiconductor laser device according to claim 3, wherein the dielectric multilayer film is configured of a total of eight layers of, in sequence from the side in contact with the laser chip, an aluminum oxide film, a silicon film, a tantalum oxide film, a silicon film, a tantalum oxide film, a silicon film, a tantalum oxide film, and a silicon film.

7. The semiconductor laser device according to claim 6, wherein the first layer, from the side in contact with the laser chip, has a thickness equivalent to λ

/2 in terms of optical length at an oscillation wavelength λ

of the laser chip, and each of the second to seventh layers has a thickness equivalent to λ

/4 in terms of optical length, and the eighth layers has a thickness equivalent to λ

/2 in terms of optical length.