| 摘要 |
PURPOSE:To easily obtain a GRIN-SCH laser, by alternately layering InP barrier layers and well layers such that the InP barrier layers as remote from an active layer are made thicker and heat treating them so that the two layered sections are made into graded layer. CONSTITUTION:An N-type InP buffer layer 2, a multiple quantum well 3 consisting of N-type InP barrier layers and N-type InGaAs well layers, an InGaAs active layer 4, an MQW 5 consisting of P-type InP barrier layers 5A and P-type InGaAs well layers 5B, a P-type InP clad layer 6 and a P<+> type InGaAsP contact layer 7 are provided on an N<+> type InP substrate 1, sequentially in that order. In the MQW 5 consisting of the N-type InP barrier layers and the N-type InGaAs well layers, the N-type InP barrier layers remoter from the InGaAs active layer 4 are thicker. This structure is heat treated and etched away from the surface thereof up to the N<+> type InP substrate 1, leaving only the central stripe portion. A highly resistive InP buried layer 8 is grown on each side of the stripe portion. An InGaAsP/InP quantum well laser can be obtained easily in this manner.
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