| 摘要 |
PROBLEM TO BE SOLVED: To obtain a highly reliable semiconductor laser having a sufficiently small droop value by setting the reflectance of a forward emission end face, the reflectance of a rearward emission end face and the length of a pumping unit, respectively, in specified ranges. SOLUTION: A buffer layer 2, an n-type clad layer 3, a strained quantum well structure layer are formed in four layers on a semiconductor substrate 1 and an active layer 4, a p-type clad layer 5, an intermediate layer 6 and a gap layer 7 are epitaxnally grown sequentially. The p-type clad layer 5 is then etched on the opposite sides to form a mesa groove and a current constriction layer 8 is formed therein before planarizing the surface. Reflectance of the forward emission end face St of a semiconductor laser is set at 55-65%, reflectance of the rearward emission end face Sf on the opposite side is set at 30-50% and the length of a pumping unit is set at 150-500μm. According to the arrangement, lowering of droop value with time can be suppressed resulting in high reliability and long service life.
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