An optical memory device is specifically so designed that, when an
reference beam is applied thereto, the entire information area of its core
layer can receive the reference beam all at a time to surely reconstruct a
correct image. The optical memory device includes a core layer and a
cladding layer laminated on both surfaces of the core layer. In this
device, at least one interface between the core layer and the cladding
layer has a concave and convex pattern for information to form a waveguide
and a reference beam is introduced into the core layer through the end of
the waveguide for reconstructing the information recorded in the concave
and convex pattern for information, and the degree of bending, .DELTA.t,
of the core layer at the end of the information area in which the concave
and convex pattern for information is formed satisfies the condition
represented by .DELTA.t.ltoreq.d-t, in which d indicates the vertical
width of the reference beam, and t indicates the thickness of the core
layer in the information area.
