| 摘要 |
PURPOSE:To control a plurality of light beams independently, by forming a curved surface at the end surface of a resonator, which is to become at least one light source, or forming the curved surfaces at the end surfaces of all the light sources, and differentiating the curvatures of the curved surfaces. CONSTITUTION:The end surface of a light emitting part 9 is made to be a convex surface. The end surface of a light emitting part 11 is made to be a concave surface. The radius of the convex surface is made to be, e.g., 30-50mum. The radius of curvature of the concave surface is made to be, e.g., 100-200mum. The astigmatism of the convex surface is -20--40mum. The astigmatism of the convex curve is 40-60mum. In this case, the difference between the astigmatisms becomes large. When the beam from the convex surface is condensed through an optical system, which can condense a light beam, the light spot from the concave surface becomes an elliptical shape having a large aspect ratio, and the light spot from the convex surface becomes a circular shape. When the end surfaces of a semiconductor laser, which has a plurality of light emitting parts, are formed so that the shapes are different for every light emitting part, a plurality of light spots having the different shapes can be formed on an optical disk through the same lens. The shapes of the end surfaces can be an elliptical surface, a parabolic surface and the like or the combination thereof.
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