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 invention relates to an optical amplifier (3) in which a source beam (1) and a pumping beam (2) are coupled.

Abstract: To avoid the phenomena of self-focusing and astigmatism of the amplified wave, the amplifier includes in succession: an input segment having an input waveguide adapted to guide a monomode input wave; a diffraction segment comprising a first medium transparent to said monomode input wave and adapted to widen it; a collimation segment; and an amplification segment having an amplifier waveguide wider than said input waveguide. The amplifier can provide a high-power laser source supplying a widened fundamental mode wave. Application to producing waves for pumping fiber optic amplifiers.

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: An epitaxial deposition process is used to deposit materials that can be crystallized lattice matched to gallium arsenide onto an indium phosphide crystalline wafer. A material of this kind forms a metamorphic layer. Metamorphic layers of this kind constitute two semiconductor Bragg mirrors to form resonant cavities of surface emitting lasers of a matrix. This matrix is consolidated by a silicon support. Applications include optical telecommunications.

Abstract: In a method of fabricating a surface-emitting laser, to assure good electrical confinement and good flatness of the mirrors defining the resonant cavity of the laser an electrical confinement layer is formed by carrying out the following steps:forming an undercut layer,at least one growth step on the undercut layer,forming a mesa defining the shape and the location of the top mirror and exposing the undercut layer on its vertical walls, andcontrolled lateral etching of the undercut layer. Applications include the fabrication of a semiconductor laser on a III-V (e.g. InP or GaAs) substrate.

Abstract: To improve the efficiency and to reduce the temperature rise of a surface emitting semiconductor laser, the laser includes between a buried active layer and a mirror, a current blocking layer incorporating an opening centered on the active layer and having dimensions less than those of the latter. Applications include optical telecommunication systems.

Abstract: In a method of fabricating a surface emitting semiconductor layer, to achieve good electrical confinement and good flatness of the mirrors delimiting the resonant cavity of the laser, an electrical confinement layer is made by growing a localized aluminum alloy layer on the active layer, except for an opening area on top of which the mirror is to be formed. After epitaxial regrowth, the alloy layer is oxidized laterally. Applications include the fabrication of semiconductor lasers on III-V substrates such as InP and GaAs.