Abstract: A focusing, adjustable device for rotating the plane of polarization of linearly polarized light in the form of a ball lens made from magnetic crystalline material preferentially magnetized in the direction of light transmission, where the ball lens consists of two domes of magnetic garnet material whose basal planes are oriented parallel to one antoher and perpendicular to the direction of light transmission, with a spherical member between the domes consisting of optically transparent non-magnetic garnet material.

Abstract: Planar optical waveguide having a crystal body consisting of a nonmagnetic substrate having a first magnetooptical layer epitaxially provided on the substrate and a second magnetooptical layer epitaxially provided on the first mangetooptical layer. The two magnetooptical layers consist of a material based on iron garnet. The second magnetooptical layer has a refractice index n.sub.2 which is approximately 1.times.10.sup.-3 to 1.times.10.sup.-2 higher than the refractive index n.sub.1 of the first magnetooptical layer. A layer of a material based on iron garnet and absorbing radiation in the wavelength range of 1.0.ltoreq..lambda..ltoreq.2.5 .mu.m is provided between the substrate and the first magnetooptical layer, said iron garnet-based layer having a refractive index n.sub.A which is higher than the refractive index of the first magnetooptical layer.

Abstract: Planar optical waveguide comprising a nonmagnetic substrate with a first magnetooptical layer produced epitaxially on the substrate, and a second magnetooptical layer produced epitaxially on the first magnetooptical layer. Both magnetooptical layers are composed of an iron garnet-based material. The second magnetooptical layer has a refractive index n which is approximately 1.times.10.sup.-3 to 1.times.10.sup.-2 greater than the refractive index of the first magnetooptical layer. The material of the magnetooptical layers contains at least one substituent at the dodecahedral sites of the garnet lattice, in particular lead. The proportions of lead are different in the materials of the first and the second magnetooptical layer. The optical waveguide can be used for optical single mode waveguides in the near infrared spectral range (0.8.ltoreq..lambda..ltoreq.1.6 .mu.m).