| 摘要 |
PURPOSE:To miniaturize an optical head device without deteriorating its characteristics by arranging a thin film wave guide element into a converging optical system so that the light beam is made incident on a grating coupler and receiving the light emitted from the end face of a thin film waveguide by a photodetector. CONSTITUTION:The light emitted from a semiconductor laser 1 is converged on a recording medium 5 via a collimator lens 2 and a convergent lens 3. The reflected light sent from the medium 5 is partly led into a thin film waveguide 8 as a converging beam by a grating coupler 9. Then this converging beam is demultiplexed into two pieces by a splitter 1 and made incident on a photodetector 7 provided on the end face of the waveguide 8. A thin film waveguide element 6 can be obtained by providing a waveguide and a grating element on a glass substrate by a sputtering process, etc., and via the dielectric substance of a high refractive index. Then it is possible to reduce the size of an optical head device without deteriorating its characteristics by converting a detecting optical system for reflected light into a thin film element. |
