| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor optical element which has an active layer comprising quantum dots and operates at high speed even at a high temperature. SOLUTION: A semiconductor optical amplifier includes: a semiconductor substrate; a first cladding layer having a first conductive type which is laminated on the semiconductor substrate; the quantum dots which are laminated on the first cladding layer and comprise semiconductor crystal grains expressing a quantum size effect by confining electrons of a conduction band and holes of a valence band three-dimensionally; the active layer comprising a barrier layer which encloses the quantum dots to confine the electrons and the holes in the quantum dots; and a second cladding layer having a second conductive type which is laminated on the active layer. A region positioned in the side surface direction of the quantum dots out of the barrier layer is doped with p-type impurities, and a region positioned in the vertical direction of the quantum dots out of the barrier layer is not doped with impurities. COPYRIGHT: (C)2009,JPO&INPIT
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