Abstract: The invention relates to a non-reciprocal optical element, particularly for use an an isolator or circulator, which is connected to at least two monomode optical waveguides and which has a magneto-optical waveguide structure which is subjected to a transversal magnetic field directed perpendicularly to the direction of propagation of the optical wave. This arrangement is simplified by combining the functions of the coupler and the phase shifter, which is achieved by means of the following features:the magneto-optical waveguide structure (1,11) is formed as a multimode waveguide which can propagate at least one fundamental mode (5) and the first-order mode (6),the optical waveguides (A,B,C,D,9,10) are off-centered with respect to the waveguide structure (1,11),the dimensions and/or the cross-sectional distribution of the refractive index of the optical waveguide structure (1,11) are chosen to be such that the two modes (5,6) have a reciprocal phase difference of (.pi.2)+pb 2n.pi.

Abstract: The invention relates to an optical polarization regulator having a wave-guide structure for converting the polarization state of an optical beam passing through and comprising devices for adjusting the coupling constants K of the TE and TM modes of the optical beam and for adjusting the difference .DELTA..beta. of the propagation constants .beta..sub.TE and .beta..sub.TM of these modes. The wave-guide structure is a magnetooptical element (8, 9, 13). The coupling constant K is adjusted by a magnetic field acting upon the wave-guide structure (8, 9, 13) and the difference .DELTA..beta. is adjusted by a mechanical deformation force exerted on the wave-guide structure.

Abstract: An optical path sensor including a filter through which passes a radiation beam comprising light of at least two wavelengths and which filter, as it is moved perpendicularly to the direction of the optical radiation beam, causes the attenuations for the beam components of different wavelengths to change in a different ratio. In a filter constructed in a simple manner with low-cost elements two phase gratings are arranged one after the other in the beam direction, only one of the gratings being movable perpendicularly to the beam direction and in that the zero-order diffraction beams are directed towards a detector.

Abstract: The invention relates to a magnetooptical waveguide device for the conversion of modes of propagation of the device. The device comprises layers (1, 4, 5, 6, 7) which are epitaxially applied to a substrate layer (8) and of which at least the waveguide layer (1) in which the modes propagate consists of a transparent magnetooptical material for which mode conversion can be induced by a magnetic field. For more accurate matching of the phase velocity of the TE and TM modes this structure is disposed in an apparatus (14, 15) by which an adjustable mechanical deformation force (24, 25) is exerted on the wave guide structure.

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.