| 摘要 |
PURPOSE:To reduce astigmatism by forming a laser resonator to a curved- surface shape in a semiconductor laser having stripe width in which a single transverse mode is obtained. CONSTITUTION:A sectional shape in a plane parallel with an active layer for a laser resonator, a semiconductor end surface, is formed to a curved-surface shape. Spot width is narrowed in a cross section such as a convex end surface 1 while the radius of curvature of a wave front (a phase front) is increased with the decrease of the radius of curvature R of the end surface, reaches infinity and takes a negative value and the absolute value is reduced again. On the other hand, spot width is broadened in a concave end surface 2, and the radius of curvature of the wave front is decreased with the shrinkage of the radius of curvature R of the end surface. Accordingly, since the end surfaces are formed to the curved-surface shape, spot width and the redius of curvature of the wave front can be altered, thus reducing astigmatism. |
