THIN FILM MAGNETOOPTIC ELEMENT

摘要

PURPOSE:To permit phase matching of a thin film magnetooptic element by setting the thickness and width of a waveguide at certain specified values so that the propagation constants of a TE wave and a TM wave are made coincident. CONSTITUTION:The thickness t1 of a waveguide is so set that the magnitude of the propagation phase constant with respect to an optical waveguide mode (TE wave) having an electric field component oscillating in the direction horizontal to a base plate attains the value smaller than the magnitude of an optical waveguide mode (TM wave) having the electrical field component oscillating in the direction perpendicular to said plate, and further the width W of the waveguide is so determined that the propagation phase constants of the TE wave and the TM wave coincide with each other. If the lattice constant of the waveguide layer adjusted by substituting a part of the yttrium element of YIG with the other rare earth ion having a large ion radius is larger than the lattice constant of the base plate, the thickness and width of the waveguide are further adequately set. The thin film magnetooptic element that permits phase matching is thus realized.