SEMICONDUCTOR LASER AND MANUFACTURE THEREOF

PURPOSE:To improve the yield of a semiconductor laser by manufacturing a BJB (Butt-Jointed Built-in) structure useful as an integrated laser by one crystal growth, thereby simplifying the manufacturing process. CONSTITUTION:After a photoresist used as a mask is removed, undoped InGaAsP active layers 2, 2' as the first semiconductor layer and P type InP or InGaAsP layers 7, 7' as the second semiconductor layer are grown by liquid phase epitaxial method on an N type InP substrate 1, and further an undoped InGaAsP photowave guide layers 5, 5' as the third semiconductor layer, and undoped INP or InGaAsP layers 8, 8' as the fourth semiconductor layers are sequentially grown continuously. In this case, since the width of mesa is wide, the respective layers are grown on the mesa, and formed separately on and under the mesa. The end of the layer 2' can be made coincident to that of the layer 5 by controlling the growing time of the layers 7, 7'.