Structures for a grating coupler and methods of fabricating a structure for a grating coupler. The structure includes a grating coupler having a central portion and edge portions. The central portion and the edge portions define a sidewall, and the central portion and the edge portions have a first longitudinal axis along which the edge portions are arranged in a spaced relationship. Each edge portion projects from the sidewall at an angle relative to the first longitudinal axis. A waveguide core is optically coupled to the grating coupler. The first longitudinal axis is aligned in a first direction, and the waveguide core has a second longitudinal axis that is aligned in a second direction different from the first direction.

An optical display system and an augmented reality electronic device are disclosed. The optical display system comprises: a waveguide; an input coupler, provided at the input end of the waveguide and couples an image light into it; and a two-dimensional grating, provided at the output end of waveguide. The waveguide delivers the image light to the two-dimensional grating, which performs pupil expansion on the image light and out-couples the expanded image light. The two-dimensional grating has rhombus lattices. Unit cells of the two-dimensional grating are un-symmetric along respective axes parallel with a propagation direction of the image light incident onto the two-dimensional grating, from a top view of the two-dimensional grating. The unit cells are oriented with the propagation direction of the image light and each of the unit cells has at least two vertexes at its end side.

An optical multiplexer reduced in background light and reduced in size is provided. The optical multiplexer takes a plurality of light beams having different wavelengths as input from respective waveguides, and outputs multiple light obtained by multiplexing the plurality of light beams by a directional coupler. Background light is reduced by a reflection groove which reflects excess light outputted from a discard port of the directional coupler, and downsizing of the optical multiplexer is achieved.

An optical assembly may include a waveguide and a Bragg grating configured to couple light into or out of the waveguide. The Bragg grating may include a plurality of layer pairs, wherein at least one layer pair comprises a first material having a first refractive index and a second layer having a second refractive index, and wherein properties of the Bragg grating are selected so that the Bragg grating exhibits a substantially similar diffractive efficiency and diffraction angle for light of at least two colors.

An optical device includes a first waveguide that propagates light in a first direction; and a second waveguide including a first mirror, a second mirror, and an optical waveguide layer. The first mirror extends in the first direction and has a first reflecting surface, and the second mirror extends in the first direction and has a second reflecting surface. The optical waveguide layer is located between the first and second mirrors and propagates the light in the first direction. A forward end portion of the first waveguide is disposed inside the optical waveguide layer. In a region in which the first and second waveguides overlap each other when viewed in a direction perpendicular to the first reflecting surface, at least part of the first waveguide and/or at least part of the second waveguide includes at least one grating whose refractive index varies periodically in the first direction.

The present invention concerns a method for constructing a light coupling system wherein a grating is manufactured on the surface of a multimode waveguide and defines the entrance of the waveguide for an incident light beam, said grating comprising a repetition of patterns. The grating is defined by a set of parameters comprising: •grating period (P), separating two adjacent patterns, •grating depth (d) between the highest and the lowest point of the pattern, •incident angle mean value (θ) of the incident light with respect to the waveguide. The method comprises a step of optimization of the set of parameters to obtain an optimized second set of parameters, in order to obtain a transmission efficiency (Ce) of the incident light into said waveguide for the first or the second diffractive order exceeding 35% for unpolarized light, or exceeding 50% for polarized light, at a given wavelength of the incident light.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch Λ, wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

The present disclosure relates to an optical waveguide system. The system has a first waveguide having a core-guide and a cladding material portion surrounding and encasing the core-guide to form a substantially D-shaped cross sectional profile with an exposed flat section running along a length thereof. The core-guide enables a core-guide mode for an optical pulse signal having a first characteristic, travelling through the core-guide. A material layer of non-linear material is used which forms a second waveguide. The material layer is disposed on the exposed flat section of the cladding material portion. The material layer forms a plasmonic device to achieve a desired coupling with the core-guide to couple optical energy travelling through the core-guide into the material layer to modify the optical energy travelling through the core-guide such that the optical energy travelling through the core-guide has a second characteristic different from the first characteristic.

A device may be provided comprising at least one optoelectronic component and at least one optical waveguide, which are configured to transfer light between the optoelectronic component and the optical waveguide, wherein the optical waveguide contains at least one first longitudinal portion in which at least one Bragg grating is introduced, which has a grating constant which is variable along the longitudinal extent of said Bragg grating, and the optoelectronic component is arranged at a lateral distance from the optical waveguide. Alternatively or in addition, a method may be provided for transferring light between at least one optoelectronic component and at least one optical waveguide.

In one embodiment, a wide-band laser beam is split into a plurality of sub-laser beams, with each sub-laser beam at a discrete wavelength. Each of the sub-laser beams is transmitted simultaneously through an antenna, with each sub-laser beam transmitted at a different angle due to properties of the antenna. Sub-laser beams that reflect off an object are received back at the same, or a different, antenna and passed to a demultiplexor. The demultiplexor passes each sub-laser to a different waveguide based on the discrete wavelength associated with each sub-laser beam. A detector receives the sub-lasers beam through the waveguides, and calculates the positions of various points on the object based in-part on which waveguide each sub-laser beam is received from and the frequency of each sub-laser beam.