| US 7,542,498 B2 | ||
| Semiconductor laser diode | ||
| Etsuko Nomoto, Sagamihara (Japan); and Tsukuru Ohtoshi, Hanno (Japan) | ||
| Assigned to OpNext Japan, Inc., Kanagawa (Japan) | ||
| Filed on Aug. 03, 2005, as Appl. No. 11/195,792. | ||
| Claims priority of application No. 2005-041640 (JP), filed on Feb. 18, 2005. | ||
| Prior Publication US 2006/0187987 A1, Aug. 24, 2006 | ||
| Int. Cl. H01S 5/00 (2006.01) | ||
| U.S. Cl. 372—45.01 [372/44.01; 372/45.012] | 18 Claims |
| 1. A semiconductor laser device comprising:
a first conduction type semiconductor substrate;
a first conduction type cladding layer formed over the substrate;
an active layer formed over the first conduction type cladding layer; and
a second conduction type cladding layer formed over the active layer,
wherein, in view of an oscillation wavelength of the semiconductor laser device, at least four layers each of which comprises
a material different from the first conduction type cladding layer are inserted in the first conduction type cladding layer,
and a distance between adjacent layers inserted in the first conductive type cladding layers is less than ¼ of a vertical
spot size over a range larger than the vertical spot size,
wherein a layer nearest to the active layer among the layers comprising a material different from the first conductive type
cladding layer is in a range of the spot size in a vertical direction, and
wherein each of the at least four layers has a refractive index higher than a refractive index of the first conductor type
cladding layer and located within the range of the spot size.
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