PURPOSE: To reduce a current density of an oscillation threshold value and to improve temperature characteristics by disposing a first clad layer having a larger band gap than that of an active layer and special thickness at the side of the active layer from a second clad layer having a lower refractive index than that of the active layer.
CONSTITUTION: Clad layers have first clad layers 14, 16 having larger band gap than that of an active layer 15 and a thickness of 0.003-0.3μm, and second clad layers 13, 17 having lower refractive indexes than that of the active layer. Here, the first clad layers are disposed at the side of the active layer from the second clad layers. Thus, the first clad layer confines carrier, and the second clad layer confines a light in the active layer. Since the first clad layer is formed of a thin film, the carrier is scarcely moved out of the active layer, and even if its lattice constant is slightly different, it can be lattice-matched to a board.
OTOMA HIROKI
UEKI NOBUAKI
FUKUNAGA HIDEKI
NAKAYAMA HIDEO
KAMIYANAGI KIICHI
SHIRAKI YASUHIRO
SHIRAKI YASUHIRO