摘要:
In a method of manufacturing a planar buried heterojunction laser, after etching to delimit a laser stripe in relief on a substrate, lateral layers to surround the stripe are formed by a non-selective growth method not only at the sides of the stripe but also above it to create a parasitic projection. This projection is then removed after separation from the substrate by selective attack of a lift-off stripe which was deposited for this purpose above the stripe prior to this etching. Passages are formed for the attack medium used for this purpose. The invention can be applied in particular to the manufacture of fiber optic transmission systems.
摘要:
In the method, a doped semiconductor coating is to be deposited on a disturbed surface (S) of a semiconductor base (9) doped with a dopant having the same conductivity type as the coating. According to the invention, prior to depositing a main layer (28) of the coating (10), a superdoped layer (24) is deposited, which superdoped layer has a dopant concentration that is greater than twice the mean concentration of the coating. The invention applies in particular to manufacturing a semiconductor laser for an optical fiber telecommunications system.
摘要:
The energization current of an indium phosphide or gallium arsenide double channel semiconductor laser is confined within a laser stripe by near and far current blocking arrangements. The near current blocking arrangements are formed by a blocking junction formed in two lateral channels delimiting the stripe. The far current blocking arrangements are formed by an iron-doped semi-insulative layer grown epitaxially before the lateral channels are etched. A particular application is to the fabrication of pump lasers used in optical amplifiers of optical fiber links.
摘要:
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.
摘要:
The invention relates to a semi-conductor optical amplifier insensitive to the polarization of light. The active layer (20) of this amplifier is made up of an alternating series of solid sub-layers alternately under tensile stress (21) and compressive stress (22) and having the same forbidden band-width. The sub-layers under tensile stress (21) favour the propagation of the TM mode of polarization of light and the sub-layers under compression (22) favour the propagation of the TE mode of polarization of light. In addition, the thicknesses of the sub-layers have values which ensure equal gains G(TE) and G(TM) for the active layer.
摘要:
Primary molecules are formed by sublimation in a sublimation chamber (2), they are then transferred at a transfer flow-rate to a decomposition head (10) at a higher temperature, and they are transformed therein into secondary molecules that are lighter in weight to form molecular beams (16). In accordance with the invention, the transfer flow-rate is adjusted by adjusting an effective vector flow-rate which is the vector flow-rate of a vector gas inserted into the sublimation chamber via a feed tube (26) and sucked out via a suction tube (30). The invention applies, in particular, to making III-V type semiconductor components by molecular beam epitaxy.
摘要:
A vacuum evaporation device incorporates a main treatment enclosure connected to an auxiliary chamber containing a material evaporation cell. The cell is fixed to a tight bellows displacement member able to displace the cell between a first advanced position towards a main enclosure and a second retracted position. A sealing valve provided with a slide is provided for the main enclosure from the auxiliary chamber, whereby the material of the evaporation cell can thus be changed without placing the main enclosure under atmosphere again. A fixed heating tube, connecting the main enclosure to the auxiliary chamber, has a first end engaged in the main enclosure and a second end issuing into the auxiliary chamber. The second end is provided with an end piece made from a thermally insulating material ensuring mechanical continuity and thermal insulation with the support part and able to bearingly receive the evaporation cell when the latter is in the advanced position. The slide of the sealing valve is inserted between the end piece and the evaporation cell when the latter is in the retracted position, the travel of the cell between these end positions and consequently travel of the bellows being limited to the space necessary for closing the valve.
摘要:
A common corrective eyeglass lens blank and a common mirror, Plano or magnifying, are brought together in a “compact” (small sized) construction and assembly to provide the very thing long desired in mirrors and not elsewhere found—corrected vision and ample working room between the eyes and any lenses, at the same time, at reasonable cost, in an elegance of implementation.
摘要:
The invention relates to wavelength converters for optical signals, as used in telecommunications, in particular for routing signals. The invention relates in particular to a wavelength converter including an interferometer structure for delivering an output optical signal, in which converter first and second branches, including at least one first semiconductor optical amplifier, are coupled to input peripheral semiconductor optical amplifiers and/or to an output peripheral semiconductor optical amplifier, wherein the structure of the active waveguide of at least one peripheral amplifier is so designed that it has a ratio of active area to confinement factor greater than that of the active waveguide of said first amplifier.
摘要:
From a top face of a semiconductor structure of the III-V type, inter-diffusion of elements between the wells and the barriers of an internal quantum structure is hot induced. The inter-diffusion is performed in one segment of the structure only, namely a segment in which the characteristic wavelength is to be shifted so as to constitute an amplitude modulator, another segment of the structure including a Bragg grating so as to constitute a laser emitter. In accordance with the invention, the inter-diffusion is induced by a layer of indium maintained in contact with the top face by means of a dielectric encapsulation layer. The invention is applicable in particular to optical telecommunications.