| 摘要 |
PURPOSE:To suppress the disorder of a far-field pattern thereby to facilitate the coupling with a fiber by composing to narrow a mesa width to the minimum by a clad layer, forming a buried layer in a multilayered structure including a p-n reverse junction, and setting the lowermost layer of the buried layer contacted with the narrowest part of the mesa width of the clad layer to a predetermined conductivity type. CONSTITUTION:A buffer layer 10 is laminated on an n-type InP substrate 9 (100). An undoped GaInAsP active layer 11, a p-type InP clad layer 12, and a p-type GaInAsP ohmic layer 13 are sequentially laminated thereon, and a crystal of a multilayered structure etched to form a reverse mesa is provided so that the mesa width becomes narrowest at the position of the layer 12. An n-type InP layer 14, and a p-type InP layer 15 as well as another n-type Inp layer 16 and an InGaAsP cap layer 17 are further provided around it. Since the vicinity of the narrowest part of the layer 12 near the side of the layer 11 becomes a p-n-p-m thyristor structure, no current flows thereto. Accordingly, no disorder occurs in a far-field pattern. |
