Optical semiconductor device and fabricating method thereof
AssigneeKabushiki Kaisha Toshiba
InventorTakayuki Matsuyama
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Abstract
An optical semiconductor device having a low threshold current and easiness of a single transverse mode oscillation is provided. The optical semiconductor device has a low device parasitic capacitance that allows a direct modulation at high speed. The optical semiconductor device comprises a first conduction type substrate, a stripe shaped active layer formed on the first conduction type substrate, a mesa shaped burying layer formed around the active layer and having a larger band gap than that of the active layer, and a groove that electrically isolates the burying layer, wherein the section of the burying layer is in an inverse trapezoid shape of which the upper base side is longer than the lower base side.
Claims11
A buried hetero semiconductor laser, comprising:
- a first conduction type substrate;
- an active layer formed in a stripe over the first conduction type substrate;
- a mesa shaped burying layer formed around the active layer and having a larger band gap than that of the active layer;
- and
- a groove that electrically isolates the burying layer,
- wherein the section of the burying layer is in an inverse trapezoid shape which has a first base side and a second base side parallel to the first base side, the second base side being closer to the first conduction type substrate than the first base side, and the first base side is longer than the second base side.
A buried hetero semiconductor laser, comprising:
- a first conduction type substrate;
- an active layer formed over the first conduction type substrate;
- a current confinement layer formed in a ridge stripe on the active layer;
- a groove that electrically isolates the current confinement layer, the groove having a space portion;
- and
- a floating wiring portion formed over the groove.
A buried hetero semiconductor laser, comprising:
- a first conduction type substrate;
- an active layer formed on the first conduction type substrate;
- and
- a mesa shaped current confinement layer formed on the active layer,
- wherein a floating wiring portion is formed around the current confinement layer.
Dependencies are inferred from the claim text.