Distributed feedback laser diode and a method for manufacturing the same
AssigneeSumitomo Electric Industries, Ltd.
InventorTakahiko Kawahara
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Abstract
The present invention is to provide a DFB-LD with a larger coupling efficiency between the grating and the active layer. The DFB-LD of the invention provides an n-type InP substrate, an n-type InP buffer layer, an AlGaInAs layer, a intermediate layer made of a material belonging to a group III-V compound semiconductor and containing phosphorous, and an active layer. The InP substrate and the InP buffer layer form a periodic undulation of the grating. Because of the AlGaInAs layer just provided on the InP buffer layer, the AlGaInAs layer and the intermediate layer can be thinned to get a flat top surface, which enhances the coupling efficiency between the grating and the active layer.
Claims15
A distributed feedback semiconductor laser diode with a diffraction grating, comprising:
- an InP semiconductor region having a surface with a periodic undulation;
- an AlGaInAs semiconductor layer provided on the surface of the InP semiconductor region, the AlGaInAs semiconductor layer having a surface with an undulation that substantially traces the periodic undulation of the surface of the InP semiconductor region;
- an intermediate layer provided on another surface of the AlGaInAs semiconductor layer, the intermediate layer being made of a semiconductor material selected from a group consisting of GaInAsP, AlInAsP and AlGaInAsP;
- and
- an active layer provided on the intermediate layer, the active layer including a quantum well structure,
- wherein the InP semiconductor region, the AlGaInAs semiconductor layer and the intermediate layer constitute the diffraction grating.
A distributed feedback semiconductor laser diode with a diffraction grating, comprising:
- an InP semiconductor region having a primary surface;
- an AlGaInAs semiconductor layer provided on the primary surface of the InP semiconductor substrate;
- an intermediate layer provided on the AlGaInAs semiconductor layer, the intermediate layer being made of one of InP, GaInAsP, AlInAsP and AlGaInAsP;
- and
- an active layer provided on the intermediate layer, the active layer including a quantum well structure,
- wherein the primary surface of the InP semiconductor substrate and the AlGaInAs semiconductor layer forms an undulation with a predetermined period, and
- wherein the InP semiconductor substrate, the AlGaInAs semiconductor layer and the intermediate layer constitute the diffraction grating.
Dependencies are inferred from the claim text.