| 摘要 |
PURPOSE:To improve a laser device, wherein an outer waveguide is coupled at edge faces of an active waveguide without gaps, by extending the edge faces of a protective layer, and extending the edge faces from the edge faces of the outer waveguide layer on both sides. CONSTITUTION:On a P-type InP substrate 1, a P-type InP buffer layer 2, an InGaAsP active waveguide 3 and an N-type InP protective layer 4 are sequentially grown. A stripe shaped SiN film 5 is formed on the N-type InP protective layer 4. Then etching is performed. A diffraction grating, which is to become a distribution Bragg reflector 6, is formed on the exposed P-type InP buffer layer 2. The InP protective layer 4 is used as a mask, and the InGaAs active waveguide layer 3 is etched from the edge faces toward inside. An N-type InGaAsP outer waveguide layer 7 is grown thereon. The InGaAsP is well turned into a space having an overhang structure. A crystal is continuously grown from the edge faces W of the InGaAsP active waveguide layer 3.
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