Optical memory reproduction apparatus and incidence positioning method for read light thereof

Abstract

An optical memory medium () has cores () each constituting a planar optical waveguide and clads () sandwiching each core, and has a data image () in which data is recorded as a scattering factor and a pair of positioning marks () which are scattering factors required for positioning at an interface between a core () and a clad () or in the core (). A read light () travels while spreading in the core () and scatters and interferes by the data image (), and data is reproduced from a data reproduction light () generated by this scattering and interference. A pair of positioning lights () are caused to enter the core () with offsets with respect to the read light () in opposite directions along a thickness direction of the core (), and scatter and interfere at the pair of positioning marks (). Incidence positions of the lights emitted from a light source () with respect to the core () in a thickness direction of the core () are controlled based on intensities of a pair of positioning mark lights () generated by this scattering and interference.