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AssigneeHitachi, Ltd.
InventorsTakashi Kajimura, Motohisa Hirao, Michiharu Nakamura, Takao Kuroda, Shigeo Yamashita, Jun-Ichi Umeda
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In certain applications, it is desirable to have a semiconductor laser device having shorter wave lengths of oscillation than are possible with conventional semiconductor lasers. To accomplish this, a semiconductor laser device is formed having a double-hetero structure, which comprises a semiconductor substrate composed of a GaAsP crystal, a first cladding layer formed on the substrate and composed of a GaAlAsP crystal of one conducting type, an active layer formed on the first cladding layer and composed of GaInAsP crystal, and a second cladding layer formed on the active layer and composed of a GaAlAsP crystal of the conducting type reverse to that of the first cladding layer. The cladding layers disposed on both sides of the active layer have a lower refractivity and a larger band gap than the active layer.
In a semiconductor laser device comprising a semiconductor substrate composed of GaAs.sub.t P.sub.l-t (0.54.ltoreq.t<1.0), a first semiconductor layer of a first conducting type formed on the substrate and composed of Ga.sub.p Al.sub.1-p As.sub.q P.sub.1-q (0.ltoreq.p.ltoreq.0.91 and 0.47.ltoreq.q.ltoreq.1.0), a second semiconductor layer formed on said first semiconductor layer and composed of Ga.sub.y In.sub.1-y As.sub.x P.sub.1-x (0.52.ltoreq.y.ltoreq.1.0 and 0.ltoreq.x.ltoreq.1.0), a third semiconductor layer of a conducting type reverse to that of the first semiconductor layer, which is formed on said second semiconductor layer and is composed of Ga.sub.p' Al.sub.1-p' As.sub.q' P.sub.1-q' (0.ltoreq.p'.ltoreq.0.91 and 0.47.ltoreq.q'.ltoreq.1.0), said second semiconductor layer containing at least one optical confinement region having a higher refractivity than those of the first and third semiconductor and a band gap smaller than those of the first and third semiconductor layers.
A semiconductor laser device comprising a semiconductor substrate composed of GaAs.sub.t P.sub.1-t (0.54.ltoreq.t<1.0), a first semiconductor layer of a first conducting type formed on the substrate and composed of Ga.sub.p Al.sub.1-p As.sub.q P.sub.1-q (0.ltoreq.p.ltoreq.0.91 and 0.47.ltoreq.q.ltoreq.1.0), a second semiconductor layer formed on said first semiconductor layer and composed of Ga.sub.y In.sub.1-y As.sub.x P.sub.1-x (0.52.ltoreq.y.ltoreq.1.0 and 0.ltoreq.x.ltoreq.1.0), a third semiconductor layer of a conducting type reverse to that of the first semiconductor layer, which is formed on said second semiconductor layer and is composed of Ga.sub.p' Al.sub.1-p' As.sub.q' P.sub.1-q' (0.ltoreq.p'.ltoreq.0.91 and 0.47.ltoreq.q'.ltoreq.1.0), said second semiconductor layer containing at least one optical confinement region having a higher refractivity than those of the first and third semiconductor and a band gap smaller than those of the first and third semiconductor layers;
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