Abstract: The present invention relates to processes for the construction of semiconductor lasers.The process according to the invention is essentially characterized in that it consists in forming a layer 1 of a laser semiconductor active medium, in forming an optical cavity 2 associated with this layer, in disposing, on at least a part of the surface of the layer, first 6 and second 7 layers of materials of impurities of opposite polarities, in causing diffusion into the active medium of at least a part of the two materials of impurities to form, in the first layer, a cylinder 8 axis substantially parallel to the axis of the optical cavity and formed of two semi-cylindrical half-shells 9, 10 of diffused impurities of opposite polarities, and in connecting two conductors 12 of the electrical energy respectively to the two half-shells.Application to the construction of a plurality of laser diodes on one and the same support substrate, to create a homogeneous and dense single laser beam.

Abstract: An optic fiber correlator having a first laser and a second laser emitting with the same frequency and with an amplitude modulated respectively by a first and second signal which are correlated. The correlator also has an optic fiber with its two ends respectively coupled to the two lasers and a length which is at least equal to the length corresponding to the maximum duration of the signals which are to be correlated and the optic fiber has a flattened surface throughout its length. A thin layer of non-centrosymmetrical structure material is applied to the flattened surface throughout the length of the fiber and light emitted by the layer is collected at a frequency which is twice the frequency of the two lasers in order to provide an electric signal which is the function of the intensity of the light and this electric signal expresses the correlation integral of the two correlated signals.

Abstract: An embodiment of the disclosed device includes: two coupled laser diodes, emitting a light wave which is modulated in frequency and amplitude by electrical signals which control the selection of one among several interconnections and represent a sequence of binary data also included is an optical guide embedded in the surface of a semiconductor substrate and a diffraction grating etched on the surface of the guide and substrate, coupled to the guide to diffract the light in several directions depending on the wavelength as well as photodiodes respectively located in one of the directions where the light can be diffracted, to give an electrical signal representing the binary data transmitted in the direction corresponding to the photodiode. In other embodiments, the photodiodes are coupled to laser diodes by means of a holographic grating.

Abstract: The source and the device comprise a generator of a pump wave, optical means for coupling with a monomode optical fiber for guiding and highly confining the pump wave so that a four photon non linear interaction is created. At least one section of this optical fiber is disposed in a thermostat controlled enclosure associated with a temperature control device so as to obtain continuous tuning in a range of frequencies belonging to the near infra red spectrum.

Abstract: A Langmuir-Blodgett film comprises at least one layer of amphiphilic molecules which are of two different types. The first type comprises molecules that are active in nonlinear optics. The second type consists of molecules that are inert or active in nonlinear optics. The mixture of these two types of molecules, in specified proportions, gives a film capable of radiating, perpendicular to the substrate, an optic wave which is a second harmonic with reference to an exciting wave.