Panasonic Corporation

Koichi Hayakawa

Isao Kidoguchi

Toru Takayama

Tomoya Satoh

Masatoshi Sasaki

A semiconductor laser device includes an n-type clad layer, an active layer, and a p-type clad layer having a ridge and wing regions. The wing regions are provided with a first trench present on one side of the ridge and a second trench provided on the other side thereof being interposed therebetween. A reflectivity Rf at a front end face of a resonator, a reflectivity Rr at a rear end face of the resonator, a minimum value Wof a width of the first trench in a region adjacent to the front end face, a minimum value Wof a width of the second trench in the region adjacent to the front end face, a width Wof the first trench at the rear end face, and a width Wof the second trench at the rear end face satisfy Rf&#x3c;Rr, W&#x3c;Wand W&#x3c;WA width Wf of the ridge at the front end face, and a width Wr of the ridge at the rear end face satisfy Wf&#x3e;Wr. The ridge includes a region where a width decreases with distance from the front end side toward the rear end side.

Semiconductor laser device

A semiconductor laser devicehaving a ridge stripe structure comprises: an n-type clad layerhaving a protrusion; and an n-type current block layercovering the clad layer, except the upper surface of the protrusion. When the width of the upper surface is W, the distance between front and rear cleavage planes is L, the width of the upper surface at the front cleavage plane is Wf, and the width of the upper surface at the rear cleavage is Wr. In a range where a distance from the front cleavage plane is shorter than or equal to L/2, an area Sc of the upper surface is in a range of L/8&#xd7;(3Wf+Wr)&#x3c;Sc&#x2266;L/2&#xd7;Wf, and W in an arbitrary position in the range is in a range of &#xbd;(Wf+Wr)&#x3c;W&#x2266;Wf.

The semiconductor laser device includes first and second light emitting portions each including a first cladding layer, an active layer and a second cladding layer, and each having a stripe structure. The stripe structure of the first light emitting portion has a section having a width changing along a resonator direction and includes a first front end face, and relationships of W&#x2267;W; W&#x3e;W; and (W&#x2212;W)/2L&#x3c;(W&#x2212;W)/2Lhold wherein Wis a width on the first front end face; Wis a width in a position away from the first front end face by a distance L; and Wis a width in a position away from said the front end face by a distance L+L(whereas L+L&#x2266;L). The stripe structure of the second first light emitting portion has a section having a width changing along a resonator direction and includes a second front end face, and relationships of W&#x2267;W; W&#x3e;W; and (W&#x2212;W)/2L&#x3c;(W&#x2212;W)/2Lhold wherein Wis a width on the second front end face; Wis a width in a position away from the second front end face by a distance L(whereas L&#x2260;L); and Wis a width in a position away from the second front end face by a distance L+L.

A semiconductor laser device includes a red-light-emission portion and an infrared-light-emission portion on a single substrate. The red-light-emission portion has a structure in which an AlGaInP-based active layer is sandwiched by a first cladding layer of a first conductivity type having a striped portion and a second cladding layer of a second conductivity type. The infrared-light-emission portion has a structure in which an AlGaAs-based active layer is sandwiched by a third cladding layer of the first conductivity type having a striped portion and a fourth cladding layer of the second conductivity type. The first, second, third, and fourth cladding layers are all made of an AlGaInP-based material. When in these layers, the Al:Ga contents are represented by X-X, X-X, X-X, and X-X, respectively, X&#x2267;Xand X&#x2267;Xare satisfied.

Growing community of inventors

Okayama, Japan

Koichi Hayakawa