Mitsubishi Denki Kabushiki Kaisha

Yoriko Tanigami

Toshitaka Aoyagi

Akihiro Shima

Akira Takemoto

Tomoko Kadowaki

A semiconductor laser device includes: a substrate serving as a heat sink; a thermal buffer plate disposed on the surface of the substrate; a first semiconductor laser chip having first and second main surfaces and including a first light emitting point in the vicinity of the first main surface, the first semiconductor laser chip being disposed on the surface of the thermal buffer plate at the second main surface; spaced apart thermal conductors disposed on the first main surface of the first semiconductor laser chip spaced from the first light emitting point with the first light emitting point between them; a second semiconductor laser chip having third and fourth main surfaces and including a second light emitting point in the vicinity of the third main surface, the second semiconductor laser chip being disposed on the thermal conductors at the third main surface so that the light radiation direction of the second semiconductor laser chip is parallel to the light radiation direction of the first semiconductor laser chip, wherein the second light emitting point is opposed to and close to the first emitting point. Even when the environmental temperature changes, the expansion and contraction of the interval between the light emitting points is smaller than in prior art structures.

Semiconductor laser device and optical disc apparatus provided with the

A semiconductor laser device includes a ridge waveguide having two side surfaces, a crystalline burying layer disposed at both side surfaces of the ridge waveguide, and a second conductivity type contact layer disposed on the burying layer and the ridge waveguide. The burying layer includes a first conductivity type first current blocking layer in contact with the side surfaces of the ridge waveguide, a second conductivity type second current blocking layer disposed on a portion of the first current blocking layer and separated from the ridge waveguide by a portion of the first current blocking layer near the ridge waveguide, a first conductivity type third current blocking layer disposed on a portion of the first current blocking layer near the ridge waveguide and on the second current blocking layer, and a second conductivity type final burying layer disposed on the third current blocking layer. In this structure, there is no pn junction at a regrowth interface between the final burying layer and the contact layer so that reduction in the forward voltage of the pn junction in continuous operation is avoided and increasing leakage current is suppressed so that the threshold current and light output of the laser do not deteriorate over time.

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Tokyo, Japan

Yoriko Tanigami