France Telecom

Centre National De La Recherche Scientifique

France Telecom Etablissement Autonome De Droit Public

France Telecom Establissement Autonome De Droit Public

French State Represented by the Minister of the Post, Telecommunications

Minister of Post, Telecommunications and Space

Jean-Michel Gerard

Benoit Deveaud-Pledran

Claude Weisbuch

Philippe Gravey

Nikolaos Pelekanos

Jean-Yves Marzin

Christian Guillemot

Dang Le Si

Bruno Gayral

Jacques Favre

Apparatus for single photon source based on emitters with frequencies distributed in a chosen manner. In one embodiment, the apparatus comprises an opto-electronic component capable or emitting light pulses containing a single photon comprising a resonant optical cavity and a group of photon emitters placed in this optical cavity, a single one of these emitters having an emission frequency equal to approximately the resonant frequency of the cavity characterised in that all emitters have a spectral distribution with a concentration of emitter frequencies at a given frequency, and in that the cavity is made so that its resonant frequency is different from this concentration frequency so that the number of emitters with an emission frequency corresponding to the resonant frequency of the cavity is close to one.

Single photon source based on transmitters with selectively distributed frequencies

A photorefractive device intended to be exposed to a marking radiation which is provided so as to create a grating of interference fringes in the device and to a reading radiation diffracted by the created grating. The device includes an electro-optical material having a quantum well structure (24) and formed in an intrinsic semi-conductor matrix (22, 24) and, on both sides of the material in the semi-conductor matrix, suitable means (28, 30) to trap, both parallel to the axis of the structure and perpendicular to this axis, free carriers generated by the marking radiation.

Photorefractive device with quantum wells

An optical operator designed to be subjected to write radiation for processing read radiation that it receives, the operator comprising an electro-optical material (Q2), first and second materials (Q1, Q3) distributed on either side of the electro-optical material (Q2), said first and second materials (Q1, Q3) being collection quantum wells. Quantum barrier forming materials (6, 8) are interposed between said two materials (Q1, Q3) and the electro-optical material (Q2), with one of the quantum barrier forming materials (6) constituting a filter such that charges of a certain sign photoexcited by the write radiation in a material (4, Q1) on one side of said filter pass through it in the absence of an external electric field to relax in the collection quantum well (Q3) situated on the other side of the filter (6), while charges of opposite sign are blocked by the filter (6) in the other collection well (Q1).

Quantum well heterostructure optical operator

This transistor incorporates at least one first stack of semi-conductor conduction layers and at least one second stack of semiconductor layers with a single, highly doped thin film within the second stack giving it the character of a mobile electric charge donor, superimposed and supported by a substrate as well as at least two potential barriers located in the second stack on either side of the doped thin film in order to reduce the concentration of carriers in said second stack a metal gate resting on the second stack for modifying the concentration of carriers of the charges in the first stack, two ohmic contacts being placed on one of the stacks, on either side of the gate and serving as the source and drain.

Thin film, field effect transistor with a controlled energy band

Photoelectric detector presenting a multiple quantum well structure, each quantum well comprising a first barrier made from a first semiconductor material, a well made from a second semiconductor material, and a second barrier made from a third semiconductor material, each semiconductor material being defined by its chemical composition, and the electric conductibility in the detector being ensured by propagation, from the first barrier to the second barrier, of given charge carriers in a given electronic band, presenting an energy extremum in each of the said materials. In accordance with the invention, said semiconductor materials are at least partly doped with carriers, the chemical composition of the first and third semiconductor materials being such that the difference in energy, between the energy extremum of the said electronic band in the first semiconductor material and the energy extremum of the said electronic band in the third semiconductor material, is greater in absolute value than the maximum energy of the optical longitudinal phonons in the second semiconductor material making up the well. Application: infrared detectors, especially in the range 2.times.10.sup.13 -4.times.10.sup.13 Hz.

Quantum well photoelectric detector with improved detectivity

A device for the conversion of infrared radiation into another form of radiation of energy greater than that of the infrared radiation comprises a multilayer semiconductor structure (4) comprising at least two layers in which an electron gas and a gas of holes which are regenerated in the course of the use of the device are combined. There is at least one delocalized electron state in the structure, at an energy greater than the energy of the ground state of the electron gas, the difference between these energies being within the infrared range. When the structure is illuminated at a non-normal incidence by radiation (10), the energy of which is equal to this difference, the structure emits a radiation (14) of greater energy, by radiative recombination involving the holes. The device finds suitable application in infrared imaging systems.

Device for the conversion of an infrared radiation into another

The object of the invention is to reduce the influence of dislocations on the functioning of structures for optoelectronic component, such as laser, made from semiconductor materials. Accordingly, one of the lasers of such a structure comprises three-dimensional inclusions in a semiconductor material with a thinner forbidden band than the forbidden band of the layer material. The inclusions are e.g. distributed over several planes of the active layer of a laser, and may be in InAs introduced into a layer in GaAs.

Growing community of inventors

Paris, France

Jean-Michel Gerard