Alps Electric Co., Ltd.

Shouichi Kyouya

Miki Ono

A light image is made irregular at an incident part of a fiber, influence of displacement of the fiber against a couping efficiency is reduced and evaluation of a lens can be carried out as usual. A light source is arranged at the optical surface side 14 of the lens 12 to be used, a focusing is formed at the second optical surface 15, the evaluation of the lens 12 is carried out by checking whether or not the surface aberration at the focusing position is less than the predetermined value. At this time, when the lens 12 is used in the optical device, the light source 1 is arranged with the second optical surface 15 being applied as a short focal point side and then the incident part for the fiber 3 is arranged with the first optical surface 14 being applied as the long focal point side. The lens 12 manufactured in such a way that the surface aberration is less than the specified value is arranged oppositely in the optical device, the surface aberration at the incident part for the fiber 3 is increased to cause the image to be irregular formed. Thus, the variation of the optical coupling efficiency against the displacement between the laser beam and the fiber is reduced.

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Kakuda, Japan

Shouichi Kyouya