| 摘要 |
PURPOSE:To improve the crystallinity of an active layer and improve the efficiency of a semiconductor laser by a method wherein an InP layer having a thickness about the same as or larger than the height of the peak of a deflection lattice is provided and the surface is levelled. CONSTITUTION:In order to obtain a selected single vertical mode oscillation, a corrugated deflection lattice 2 is provided on an InP substrate 1 and an InGaAsP crystal layer 6 is formed on the lattice 2 by liquid crystal growth so as to have a thickness about a half of the depth of the valley of the deflection lattice 2. Then, in order to reduce the influence of crystal defects existing in the deflection lattice 2 part, an InP crystal layer 7 is built up so as to have a thickness about the same as or larger than the height of the peak of the deflection lattice 2 to level the top surface of the InP crystal layer and an active layer 4 is formed on the InP crystal layer 7. By levelling the surface as described above, the influence from the deflection lattice 2 at the time of forming the active layer 4 can be suppressed and the crystallinity of the active layer can be improved and, by making the thickness of the InGaAsP crystal layer 6 which functions as a light absorber to be thin, the oscillation efficiency can be improved. |
