Monolithic optical pick-up using an optical waveguide

摘要

An optical pick-up for use in an optically information recording and reproducing apparatus is provided. The pick-up includes a substrate on which an optical waveguide layer is formed and a grating coupler is formed on the optical waveguide layer. Photosensors are also provided to receive light travelling along the waveguide from the grating coupler. A beam splitter is also formed on the substrate for splitting the light from the grating coupler into two separate light beams before reception by the photosensors. If the substrate is opaque, the substrate is formed with an opening through which light emitted from a light source passes. An objective lens is also provided for focusing the light emitted from the light source onto the information recording surface of an optical disc. A quarter wavelength plate may also be provided to change the nature of polarization of the light used.