SEMICONDUCTOR OPTICAL ELEMENT HAVING WIDE LIGHT SPECTRUM EMISSION CHARACTERISTICS, METHOD FOR FABRICATING THE SAME, AND EXTERNAL RESONATOR TYPE SEMICONDUCTOR LASER

摘要

A semiconductor optical element comprising a semiconductor substrate, and an active layer having a plurality of quantum wells consisting of a plurality of barrier layers formed above the semiconductor substrate and a plurality of well layers sandwiched by the plurality of barrier layers. At least one of the plurality of well layers comprises an In_xaGa_(1-xa)As film wherein the composition ratio xa of In is any value in the range of approximately 0.05 to approximately 0.20. Consequently, the semiconductor optical element is formed as a strained well layer where the lattice strain occurring in the well layer is any value in the range of approximately 0.35% to approximately 1.5%, and the strained well layer is formed to have a band gap wavelength different from that of other well layers. Consequently, the semiconductor optical element is constituted to present wide light spectrum characteristics having a central wavelength from approximately 800 nm to approximately 850 nm and a spectral half peak width of a predetermined value or above.