Abstract: The invention relates to magnetometers making it possible to measure a magnetic field by the Faraday effect in a thin YIG layer which involves taking a YIG layer which is sufficiently thick to permit a multimode transmission of the polarized light beam, as well as the entrance and exit of said beam from the edge of the layer. This device makes it possible to produce a magnetometer head, whose elements are integrated on a substrate and whose volume is approximately 1 cm.sup.3.

Abstract: The device according to the invention comprises a wave guide formed by a thin layer of a ferrimagnetic garnet deposited onto a substrate, preferably by epitaxy, and capable of propagating first and second modes of radiated energy, means for exciting the first mode in said layer, means for inducing a magnetic field in the propagation direction to enable at least a fraction of the propagated energy to be transferred from the first mode towards the second mode, means for selectively transmitting one of the two modes situated in front of the guide, for example a metallic layer deposited onto the thin layer and means for extracting the energy of the transmitted mode.

Abstract: The invention relates to an electrically-controlled optical branch connection, for the guiding of an optical radiation from one input optical fibre to one of n output fibres or vice versa, obtained by associating a plurality of basic cells. Each basic cell comprises an optical guide capable of being controlled electrically so as to produce or not produce, depending on the control signal, a rotation through .pi./2 of the linear polarization at the input of the guide. The axes are so chosen that the polarized radiation issuing from the guide is propagated in the ordinary direction or the extraordinary direction in a bi-refracting plate.

Abstract: The arrangement according to the invention comprises three branches 1, 2 and 3 and enables a polarized radiation to be transmitted from the branch 1 towards the branch 2 or from the branch 2 l towards the branch 3. It comprises polarization separating means forming a fork between the branches 1 and 3 on the one hand and the branch 2 on the other hand, the common section of said fork communicating with the branch 2 through non-reciprocal means which turn the polarization of the radiation through 45.degree..

Abstract: The invention concerns the magneto-optical deflectors which enable an incident beam of radiant energy to be deflected in a variable manner under the control of a magnetic field. It consists in using a thin film of a magnetic material forming a diffraction grating, means for travelling the incident beam along the plane of this thin film, and means for magnetically controlling the step-width of the grating, thus controlling the angle of deflection given by this grating.

Abstract: The present invention relates to devices intended to measure magnetic fields, and also known as magnetometers. It consists in using a zeroing method to measure the influence of the Faraday effect of the field being measured, upon a radiated energy beam propagating in guided fashion through a thin film of magnetic material.

Abstract: A device for converting the propagation mode of radiated energy, ulitizing the Cotton-Mouton effect. It is constituted by a substrate upon which there is deposited an epitaxially produced film of yttrium-iron garnet, magnetized in a direction having at least one component normal to the direction of energy propagation, and with a thickness such that the propagation velocities of the two modes, initial and final, are identical to one another.