Abstract: A microwave circuit includes at least one inductive portion and at least one capacitive portion and having a resonance frequency, the microwave circuit including a material which acts as a dielectric for the capacitive portion, characterized in that the material acting as a dielectric includes an active region that is an electrically pumped semiconductor heterostructure having at least two energy levels whose energy separation is close to the resonance frequency of the microwave circuit.

Abstract: A microwave circuit includes at least one inductive portion and at least one capacitive portion and having a resonance frequency, the microwave circuit including a material which acts as a dielectric for the capacitive portion, characterized in that the material acting as a dielectric includes an active region that is an electrically pumped semiconductor heterostructure having at least two energy levels whose energy separation is close to the resonance frequency of the microwave circuit.

Abstract: Quantum cascade laser especially comprising a gain region (14) formed from several layers (20) which each comprise: alternating strata of a first type (26) each defining a quantum barrier made of AlInAs and strata of a second type (28) each defining a quantum well made of InGaAs, and injection barriers (22), interposed between two of the layers (20). The layers of the gain region (14) each constitute an active region extending from one to the other of the injection barriers (22) which are adjacent to it. The strata (26, 28) are dimensioned such that: each of the wells comprises, in the presence of an electric field, at least a first upper subband, a second middle subband and a third lower subband and that the probability of an electron being present in the first subband is highest in the vicinity of one of the adjacent barriers, in the second subband in the middle part of the region and in the third subband in the vicinity of the other of the adjacent barriers.

Abstract: The invention concerns a quantum cascade laser, comprising a substrate, a stack of layers, having a prismatic shape with substantially trapezoidal cross-section, comprising a lower surface arranged on the substrate, an upper surface and lateral surfaces, said stack forming a gain region and two walls between which the region is interposed, two electrodes arranged on either side of the stack, one of which is formed by an electrically conductive material layer covering at least partially the surface of the stack opposite the substrate, and an electrically insulating layer interposed between the two electrodes. The invention is characterised in that the electrically insulating layer completely covers the lateral surfaces of the prism, without overlapping on the upper surface, and its thickness is equal to at least a third of the stack thickness.

Abstract: A quantum cascade laser comprising two electrodes (10, 18) for applying an electric control field and a waveguide placed between the two electrodes and which comprises: a gain region (14) consisting of several layers (20) which each comprise alternating strata (22) of a first type each defining a quantum barrier and strata (24) of a second type each defining a quantum well, and two optical confinement layers (12, 16) placed on each side of the gain region (14). According to the invention, each layer (20) of the gain region (14) is arranged so that the active region has three subbands, the potential differences between them being such that the transition of an electron between the two furthermost emits an energy (EGH, EHJ) corresponding to that needed for the emission of two optical phonons.

Abstract: Quantum cascade laser especially comprising a gain region (14) formed from several layers (20) which each comprise:

Abstract: The invention concerns a quantum cascade laser, comprising a substrate, a stack of layers, having a prismatic shape with substantially trapezoidal cross-section, comprising a lower surface arranged on the substrate, an upper surface and lateral surfaces, said stack forming a gain region and two walls between which the region is interposed, two electrodes arranged on either side of the stack, one of which is formed by an electrically conductive material layer covering at least partially the surface of the stack opposite the substrate, and an electrically insulating layer interposed between the two electrodes. The invention is characterised in that the electrically insulating layer completely covers the lateral surfaces of the prism, without overlapping on the upper surface, and its thickness is equal to at least a third of the stack thickness.

Abstract: A quantum cascade laser comprising two electrodes (10, 18) for applying an electric control field and a waveguide placed between the two electrodes and which comprises:

Abstract: The invention concerns a quantum cascade laser, comprising a substrate (10), a stack of layers (12), having a prismatic shape with substantially trapezoidal cross-section, comprising a lower surface arranged on the substrate (10), an upper surface and lateral surfaces, said stack forming a gain region and two walls between which the gain region is interposed, two electrodes (10, 24) arranged on either side of the stack, one (24) of which is formed by an electrically conductive material layer covering at least partially the surface of the stack opposite the substrate, and an electrically insulating layer (22) interposed between the two electrodes. The invention is characterised in that the electrically insulating layer (22) completely covers the lateral surfaces of the prism, without overlapping on the upper surface, and its thickness is equal to at least a third of the stack (12) thickness.

Abstract: A QC laser comprises first and second optical confinement (i.e., cladding) regions, and an In-based, Group III-V compound, QC active region disposed between the confinement regions. At least the first confinement region and the active region having the shape of an elongated mesa. An i-type InP layer covers the sidewalls to provide efficient heat transport and effective low loss mode confinement. A metal layer makes ohmic contact with the top surface of the mesa and a rectifying contact with the i-InP layer.