Sharp Kabushiki Kaisha Corporation

Chitose Sakane

Haruhisa Takiguchi

Hiroaki Kudo

Satoshi Sugahara

Toshihiko Yoshida

Shinji Kaneiwa

A semiconductor laser device with a resonator containing an active region for laser oscillating operation is disclosed which comprises a third-order diffraction grating with a periodic corrugation for producing feedback of laser light, the corrugation being of substantially rectangular shape, wherein the ratio of the width of each convex portion of the corrugation to the periodicity of the corrugation is in the range of 0.20 to 0.25, 0.40 to 0.60, or 0.70 to 0.95.

Semiconductor laser device

A semiconductor laser device is disclosed which comprises an active layer positioned between a first cladding layer and a second cladding layer, the active layer being made of a compound semiconductor material selected from the group consisting of (Al.sub.x Ga.sub.1-x).sub.0.5 In.sub.0.5 P (0.ltoreq.x.ltoreq.0.7), Al.sub.x Ga.sub.1-x As (0.ltoreq.x.ltoreq.0.4), and Ga.sub.x In.sub.1-x P.sub.1-y As.sub.y (0.5.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, and y=2x-1), wherein an optical guiding layer having a diffraction grating made of (Al.sub.x Ga.sub.1-x).sub.0.5 In.sub.0.5 P (0.ltoreq.x.ltoreq.1) is positioned between the active layer and one of the cladding layers.

A multi-layered dielectric film that is coated on the end surfaces or other surfaces of optical products, wherein said multi-layered dielectric film is composed of alternate layers consisting of two kinds of dielectric layer, one of which is a first dielectric layer of TiO.sub.2 or ZnS with a high refractive index n.sub.1 and the other of which is a second dielectric layer of Al.sub.2 O.sub.3 with a low refractive index n.sub.2.

Multi-layered dielectric film

A semiconductor laser device comprising a double-heterostructure that is composed of an active layer and a pair of cladding layers sandwiching the active layer therebetween, and a stripe structure that is disposed on the double-heterostructure, the stripe structure being composed of a current blocking layer with a conductive type different from that of the adjacent cladding layer, and the current blocking layer having a striped groove constituting a current path, wherein the cladding layer that contacts the current blocking layer is composed of an In.sub.1-s Ga.sub.s P.sub.1-t As.sub.t crystal material (wherein 0.51.ltoreq.s.ltoreq.1, 0.ltoreq.t.ltoreq.1 and s=2.04t-1.04).

Growing community of inventors

Nara, Japan

Chitose Sakane