| 摘要 |
PURPOSE:To obtain an element oscillating at a single mode even at the time of unsteady operation by forming a high resistance region into at least one clad layer at approximately the same period as light wavelength while being made perpendicular to the direction of optical propagation in a semiconductor laser element having double hetero-junctions in which an active layer is held between two clad layers. CONSTITUTION:A P-type InP clad layer 3 is liquid-epitaxial grown onto a P-type InP substrate 2, and an undoped InPGaAsP active layer 4 and an N-type InP clad layer 5 are laminated and grown on the layer 3. In the constitution, Fe ions are implanted linearly to the layer 5 while width is constricted to approximately 0.15mum and being made perpendicular to the direction of optical propagation from an upper section through a focussed-ion beam method, and a high resistance region 9 having a resistance value different from other sections of the layer 5 is shaped. The depth of implantation is brought to 0.2-0.3mum so as to be brought close to the layer 4 as much as possible at that time, and the same operation is repeated and a period of approximately 0.23mum in the same extent as optical wavelength is acquired. Accordingly, periodic current blocking structure is formed, and gains in a resonator are changed periodically.
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