Semiconductor laser and process for producing the same

摘要

PCT No. PCT/JP96/03837 Sec. 371 Date Nov. 13, 1997 Sec. 102(e) Date Nov. 13, 1997 PCT Filed Dec. 26, 1996 PCT Pub. No. WO97/24787 PCT Pub. Date Jul. 10, 1997In a semiconductor laser device 100, an n-type InGaAsP light confinement layer 2, a multiple quantum well active layer 3, a p-type InGaAsP light confinement layer 4, and a p-type InP cladding layer 5 are formed on an n-type InP substrate 1 to be in a mesa structure extending in stripes along the cavity length direction. Moreover, regions on both sides of this striped mesa are buried with a p-type InP current blocking layer 6 and an n-type InP current blocking layer 7. Furthermore, a p-type InP burying layer 8 and a p-type InGaAsP contact layer 9 are formed thereon. The oscillation wavelength of the semiconductor laser device 100 is around 1.3 mu m. The stripe width of the active layer 3 is such that the width W1 at the front end face and the width W2 at the rear end face have a relationship of W1<W2, and the stripe width is continuously reduced from W2 to W1 along the cavity length direction. Thus, a semiconductor laser device is provided which has a very narrow beam divergence and a low threshold current and generates a high optical output.