摘要:
The present invention relates to novel isocyano derivatives of linear or cross-linked, natural or synthetic macromolecules, the derivatives being of the general formula P--O--Q--NC, wherein P is the macromolecular backbone, the oxygen atom is part of the hydroxy group, Q is a group --(CH.sub.2).sub.n --wherein n is an integer of at least 3 carbon atoms, and up to about 20 carbon atoms, or Q is an aralkyl group, to a process for preparing such derivatives and to a process of linking to same biologically active proteins and to the products thus obtained.
摘要:
A semiconductor Bragg reflector and to a method of fabricating it. The reflector comprises a plurality of stacked layers on a substrate of a III-V type material, one of the stacked layers forming a holographic grating. The layer forming the grating comprises an alternating succession of air pockets and of III-V type material. Such a reflector is particularly suitable for use in laser devices.
摘要:
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.
摘要:
An optical waveguide includes, in monolithic manner, a rear segment, a transition segment, and a front segment extending and succeeding one another along the length of the waveguide. A lateral confinement factor and a width the waveguide are respectively larger and smaller in the rear segment than in the front segment. According to the invention, the width increases in the transition segment until it reaches a value that is larger than that of the front segment. The invention is particularly applicable to integrating together a laser and an optical modulator for a telecommunications system.
摘要:
The invention concerns a semiconductor optical amplifier. The optical guide structure of this amplifier comprises a rectangular cross-section active stripe (12). Its material is homogeneous and it is subjected to a tensile strain sufficient to render the amplifier insensitive to the polarisation of the light to be amplified.The invention finds an application in optical telecommunications.
摘要:
In order to facilitate resuming molecular beam epitaxy after etching a substrate or an epitaxial layer, the etching method is implemented in an ultra-high vacuum, and it consists in producing at least two simultaneous chemical beams converging towards the substrate or the layer, the beams being formed of substances, each of which is capable of reacting with elements of different types in the substrate or the layer so as to form volatile compounds. Application in particular to manufacturing photonic and optoelectronic components.
摘要:
Novel substituted polyamides of the general formula ##EQU1## wherein A and B, which may be identical or different, are the hydrocarbon backbone groups of the formula --(CH.sub.2).sub.n --, where n is an integer, R.sub.2 and R.sub.3 are the residues of an aldehyde R.sub.2 --CHO or of an isocyanide R.sub.3 --N.tbd.C, where R.sub.2 and R.sub.3 are aliphatic, aromatic or heterocyclic residues of the respective aldehyde or isocyanide, or where R.sub.3 is a chromophoric moiety. R.sub.2 and R.sub.3 can be substituted, and amongst the possible substituents there may be R.sub.3 designating --(CH.sub.2).sub.n --NHCO--CHR.sub.2 --N(CO)(R.sub.4)--X, where R.sub.4 is the residue of a monocarboxylic or dicarboxylic acid and X is the lysyl residue of a protein, which may be biologically active, or the residue of a low-molecular weight compound containing a primary amine moiety. Preferred polyamides are various types of nylons. Amongst proteins chemically bound to the polyamide there may be mentioned enzymes, antibodies and peptide hormones. When R.sub.3 is a chromophoric moiety, the product is a chemically dyed polyamide. The invention relates also to a process for the production of such novel substituted polyamides.
摘要:
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.
摘要:
To form an integrated optical component comprising a thick waveguide coupled to a thin waveguide, the method consists in:depositing a first guiding layer of said thick waveguide on a substrate;locally etching said first guiding layer over a portion allocated both to a coupling interface and to the thin waveguide;depositing a second guiding layer on the first guiding layer and on the locally etched portion so as to form said thick waveguide in a manner such that it has a maximum thickness in a first zone, a graded-thickness section in a second zone, and a reduced-thickness section in a third zone;locally etching the second guiding layer over a portion of the third zone, said portion being allocated to the thin waveguide; anddepositing a third guiding layer in said portion of said third zone so as to form said thin waveguide.
摘要:
A semiconductor photonic diplex transceiver includes a laser to generate a first optical signal having a certain wavelength and a photodetector to detect a second optical signal having another wavelength. The diplex transceiver also includes an absorber of the first signal disposed between the laser and the detector which form integral parts of an optical waveguide. The laser generates the first signal in the form of a continuous wave and is disposed between the absorber and a selective modulator of the first signal. This reduces the problems of optical and electrical crosstalk between the transmit and receive functions. Applications include user premises optical fiber transmit/receive equipments.