Abstract: The present invention provides a vertical structure semiconductor laser comprising bottom and top cladding layers (1, 2), a light guide (G) superposed on the bottom cladding layer, and a semiconductor active layer (CA). In the invention, the light guide (G) further comprises: a semiconductor bottom guide layer (11) having the following two adjacent bottom parts: an undoped first bottom part (11a) adjacent the central region, and an n-type doped second bottom part (11b) adjacent the bottom cladding layer, a semiconductor top guide layer (12) having the following two adjacent top parts: an undoped first top part (12a) adjacent the central region, and a p-type doped second top part (12b) adjacent the top cladding layer. The first bottom and top parts form a non-doped region (ND) more than 0.5 &mgr;m thick, and the refractive index difference (&Dgr;nopt) between one or each of the cladding layers and the adjacent guide layer is less than 0.02.

Abstract: In a device for regenerating a wavelength-division multiplex optical signal, the optical signal to be regenerated comes from an optical fiber and is injected back into the same optical fiber or into another fiber. The device comprises at least one dispersive medium for receiving the wavelength-division multiplex signal and emitting a corresponding dispersed wave into a free space and a saturable absorber which receives the dispersed wave and transmits a corresponding regenerated wave.

Abstract: The present invention provides a vertical structure semiconductor laser comprising bottom and top cladding layers (1, 2), a light guide (G) superposed on the bottom cladding layer, and a semiconductor active layer (CA).

Abstract: A method of fabricating a semiconductor component, the method including at least one step of etching an upper layer formed on a substrate. In the method, prior to forming the upper layer, at least one set made up of marker layers separated by intermediate layers of predetermined thicknesses is caused to be grown, where the marker layers and adjacent intermediate layers have different refractive indices, and then during etching of the upper layer refractive index discontinuities are detected optically and etching is stopped when the sequence of the optically detected discontinuities corresponds to a reference sequence representative of the thicknesses of the intermediate layers.

Abstract: Two semiconductor layers of the laser form a tunnel junction enabling an electrical current for pumping the laser to pass from an N doped semiconductor Bragg mirror to a P doped injection layer belonging to the light-amplifying structure. The Bragg mirror co-operates with another mirror of the same type having the same doping to include said structure in an optical cavity of the laser. In a variant, the tunnel junction may be buried and located so as to constitute confinement means for said pumping current. The laser can be used in an optical fiber communications network.

Abstract: In order to operate at high frequencies and at high optical powers without reducing the possible depth of modulation, a quantum well electro-optical modulator has a semiconductor structure of III-V elements including, in succession, an n doped layer, an undoped layer, a quantum well active layer and a p doped layer. Applications include optical transmission systems.