Optical system for waveguide

Abstract

Abstract PURPOSE:To obtain an optical spot having high energy density of light and roughly a circular shape by providing means for increasing the coupling length of an optical coupler and obtaining a desired distribution of the light intensity at the spot. CONSTITUTION:A charge film 23 having the refractive index lower than the refractive index of an optical waveguide 12 and a prism optical coupler 14 is provided between the coupler 14 and the waveguide 12. The coupling of guided light 24 to the coupler 14 is weakened by such film, by which the coupling length is increased and the intensity distribution of an exit luminous flux 25 is more gently attenuated in the direction Zr. The intensity distribution of the flux 25 attenuates consequently in the direction (y) and the direction Zr at about the same distance and the shape of the spot condensed by a lens 16 is approximately circular. The coupling length is preferably so set that the intensity of the flux 25 in the sagittal direction is distributed roughly at 2R width particularly when the luminous flux width of the guided light is designated as 2R and the pupil radius of the condenser lens as R in order to obtain the light spot having an approximately circular shape in the above-mentioned way.

Inventors

• 👤 Mamoru Miyawaki
• 👤 守 宮脇
• 👤 Yuichi Handa
• 👤 祐一 半田

Bibliographic Details