| 摘要 |
PURPOSE:To correct aberrations by adjusting partially the quantity of ultraviolet rays or light irradiated to a thin film consisting of an arsenic sulfide if the shape of a recess is deviated from a design and aberrations occur in a geodesic lens. CONSTITUTION:If the center of the recess is deeper than the design, the refractive index of an optical waveguide 7 consisting of an arsenic sulfide provided on the recess is raised gradually in the direction vertical to the propagation direction of a guided light according as going away from the optical axis, but is uniform in the propagation direction of the incident guided light. Consequently, since the part along the optical axis in the waveguide in the recess has the lowest equivalent refractive index if the depth of the recess 3 is deeper than the design and the optical path length of the beam propagated is most deviated from the design value, the propagation speed of the beam passing the optical axis is high to cancel the phase difference due to the extension of the optical path length, thus obtaining the geodesic lens having no aberrations. |
