摘要:
The polariser is formed on a silicon rib waveguide (4) having an upper face and two side faces, and comprises a section of the silicon rib waveguide (4) with a buffer layer (6) and a light absorbing layer (7) on either the upper face of the rib or at least one side face of the rib. The buffer layer (6) has a refractive index similar to that of the waveguide (4) such that light travelling along the waveguide (4) and incident upon the respective face thereof passes into the buffer layer (6) and then into the light absorbing layer (7) so either the TM (transverse magnetic) or TE (transverse electric) mode of the light travelling along the waveguide is attenuated.
摘要:
Dispositif de diffraction d'ondes lumineuses formé d'une couche diélectrique (4), d'une structure réfléchissante (12) agencée à une face inférieure (10) de cette couche et d'un réseau de diffraction (8) agencé à une face (6) de cette couche. La hauteur (H) de la couche est sélectionnée de manière à ce que la condition de résonance pour un mode à fuite dans cette couche pour au moins une onde incidente donnée, ayant une longueur d'onde λ et un angle d'incidence déterminé, soit sensiblement satisfaite. Ensuite, le réseau de diffraction présente une période spatiale sélectionnée pour que l'onde incidente soit diffractée essentiellement selon le premier ordre négatif de diffraction et sous angle de diffraction différent de l'angle d'incidence (hors de la condition de Littrow). Il est prévu en particulier que soit l'angle d'incidence, soit l'angle de diffraction soit élevé, c'est-à-dire relativement proche de 90° depuis la direction normale au réseau de diffraction. Ce dispositif de diffraction permet d'obtenir une efficacité de diffraction très élevée, jusqu'à 100 %, même lorsque l'onde incidente est rasante.
摘要:
A True Time Delay system for creating variable time delays of an optical signal suitable for use with a phased array antenna system in order to avoid beam-squint in broadband applications. The TTD is adapted to be integrated on a planar silica waveguide in order to substantially reduce the package size of the device. In one embodiment of the invention, the TTD is formed from a polarization beam splitter (38), a polarization rotator (42) and a spiral waveguide (44). In an alternate embodiment of the invention, the TTD includes a polarization sensitive Mach Zehnder interferometer (58), a quarter wave polarization rotator and a spiral waveguide. In both embodiments of the invention Bragg reflective gratings (48,50 and 52) are written into the spiral waveguide at different spacings to reflect optical signals of different wavelengths to create various time delays.
摘要:
A True Time Delay system for creating variable time delays of an optical signal suitable for use with a phased array antenna system in order to avoid beam-squint in broadband applications. The TTD is adapted to be integrated on a planar silica waveguide in order to substantially reduce the package size of the device. In one embodiment of the invention, the TTD is formed from a polarization beam splitter (38), a polarization rotator (42) and a spiral waveguide (44). In an alternate embodiment of the invention, the TTD includes a polarization sensitive Mach Zehnder interferometer (58), a quarter wave polarization rotator and a spiral waveguide. In both embodiments of the invention Bragg reflective gratings (48,50 and 52) are written into the spiral waveguide at different spacings to reflect optical signals of different wavelengths to create various time delays.
摘要:
Le composant comporte des structures, réalisées en optique intégrée, exerçant des contraintes prédéterminées sur un guide d'onde de transmission (1) de manière à maintenir ou à modifier de manière prédéterminée l'état de polarisation d'une onde lumineuse incidente. Ces structures sont constituées par au moins un guide d'onde plan segmenté (3) disposé latéralement par rapport au guide d'onde de transmission (1) et constitué par des guides d'onde latéraux (4) parallèles et perpendiculaires à l'axe longitudinal du guide d'onde de transmission. Ces structures sont réalisées en même temps que le guide d'onde de transmission, les guides d'onde plans segmentés ayant des indices de réfraction inférieurs ou égaux à ceux du guide d'onde de transmission. De telles structures peuvent être disposées symétriquement ou asymétriquement, alternativement de part et d'autre du guide d'onde de transmission.
摘要:
A waveguide-type optical interferometer includes at least one input waveguide (101, 102), an optical splitter (103) connected to the input waveguide (101, 102), at least one output waveguide, an optical combiner (106) connected to the output waveguide (104, 105), at least two arm waveguides (123a, 123b, 123c, 123d) that provide a connection between the optical splitter (103) and the optical combiner (106), and a half-wave plate (122) having an optic axis inclined at any one of 45° and -45° relative to optic axes of the at least two arm waveguides (123a, 123b, 123c, 123d). The waveguide-type optical interferometer further comprises phase difference providing waveguide portions (170) that provide a phase difference of 180° between polarizations crossing at right angles in the at least two arm waveguides (107, 108), at operating wavelengths used in the optical interferometer, the phase difference providing waveguide portions (170) being located either between the at least two arm waveguides (123a, 123b, 123c, 123d) and the optical splitter (103) or between the at least two arm waveguides (123a, 123b, 123c, 123d) and the optical combiner (106), wherein the half-wave plate (122) is located at a location corresponding to a midpoint of an optical path length of each of the at least two arm waveguides (123a, 123b, 123c, 123d).
摘要:
Provided is a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed. The waveguide-type polarization beam splitter includes: an input optical waveguides (11); a first optical coupler (12) coupled to the input optical waveguides (11); a pair of optical waveguide arms (13a, 13b) coupled to outputs of the first optical coupler; and a second optical coupler (18) coupled to the pair of optical waveguide arms (13a, 13b). A groove (15) is formed to extend across the pair of optical waveguide arms (13a, 13b) and two quarter wave plates (16a, 16b) are provided in the groove (15) to extend respectively across the arms (13a, 13b). Polarization axes of the quarter wave plates (16a, 16b) are orthogonal to each other. The first optical coupler (12) which gives a phase difference of 0° or 180° between coupled or split light beams and the second optical coupler (18) which gives a phase difference of 90° or -90° between coupled or split light beams are used in combination.