Method of manufacturing a semiconductor laser

A method of manufacturing a semiconductor laser, comprising:

• forming an active layer over a substrate;
• and
• diffusing impurities into a region near an end surface of said active layer to alloy said active layer, wherein said alloying said active layer includes:
• preparing a semiconductor layer A and a semiconductor layer B;
• sequentially forming said semiconductor layer B and said semiconductor layer A over said active layer when the solid solubility limit concentration of said semiconductor layer A with respect to said impurities is Ma and the solid solubility limit concentration of said semiconductor layer B with respect to said impurities is Mb (Ma>Mb);
• forming a groove in said semiconductor layer A between a region where said region near said end surface is to be formed and a region where a region other than said region near said end surface is to be formed;
• and
• forming a layer including said impurities so as to come into contact with only the surface of said first semiconductor layer A in said region where said region near said end surface is to be formed or exposing only the surface of said semiconductor layer A in said region where said region near said end surface is to be formed to a gas including said impurities, and diffusing said impurities into said active layer in said region where said region near said end surface is to be formed through said semiconductor layer A and said semiconductor layer B.