OPTICAL HEAD DEVICE

摘要

PURPOSE:To improve the coupling efficiency of output and input light without deteriorating the light condensing property by constituting a coupling means of a dielectric material provided on a waveguide and a prescribed conical type reflecting prism. CONSTITUTION:A waveguide layer 12 having a high refractive index and a dielectric layer 13 having a low refractive index thereon and the conical type reflecting prism 8 are provided on both sides of a transparent layer 11 formed with a grating 10 on a waveguide substrate 9. Laser light 7 polarized to concentrical circular polarized light by a quarter wave plate 3 and a polarizer 2 is reflected by the prism 8 and is inputted and coupled into the waveguide layer 12, by which guided light 14 is obtd. The guided light 14 is made into a radiation mode 27 by the grating 20 and is condensed onto an optical disk 15. The reflected light 20 from a disk reflecting surface 16 is inputted and coupled by the grating 20 to form guided light 21. The quantity of light is detected by a photodetector 24.