| 摘要 |
PURPOSE:To make to nearly nil the current to pass through the external waveguide region and to contrive a reduction in the threshold current and the improvement of the reliability of the titled semiconductor laser by a method wherein the mesa striped structure is formed into a form that the width of the part of the active waveguide layer is narrower and the widths of the parts of the distributed Bragg- reflectors are wider. CONSTITUTION:First, an InGaAsP active waveguide layer 3 and an N-type InP protective layer 4 are grown on a P-type InP substrate 1, a laminated material 21 is made and after an etching protective film is formed on the central part of the upper surface, an etching is performed up to reach the substrate 1, then distributed Bragg-reflectors 10 are formed on the upper surface of the substrate 1 by etching. Then, a second growth is performed, an N-type InGaAsP external waveguide layer 5 and an N-type InP layer 15 are formed and after an etching protective film is formed on the upper surface, an etching is performed and a mesa striped structure 22 is formed. In this case, the mesa striped structure is formed into a structure wherein the width of the part 22a of the layer 3 is narrower and the widths of the parts 22b of the reflectors 10 are wider. Then, an N-type InP layer 16, a P-type InP layer 17 and an N-type InP layer 18 are grown in order on the upper surface of the layer 15. |
