A millimeter scale weak grating coupler comprising a silicon waveguide having bars of overlay material of length (a) disposed periodically at a period (∧) adjacent the silicon waveguide whereby a uniform grating output is achieved.

An optical fiber includes a core with radius r1, a first clad layer with outermost radius r2 adjacent to the core at radial position r1 and covering the outer periphery of the core, a second clad layer with outermost radius r3 adjacent to the first clad layer at radial position r2 and covering the outer periphery of the first clad layer, and a third clad layer adjacent to the second clad layer at radial position r3 and covering the outer periphery of the second clad layer. The refractive index of the first clad layer decreases continuously from the inside to the outside, reaching a maximum value at radial position r1 and a minimum value at radial position r2. The refractive index of the second clad layer increases continuously from the inside to the outside, reaching a minimum value at radial position r2 and a maximum value at radial position r3.

An optical fiber includes a core with radius r1, a first clad layer with outermost radius r2 adjacent to the core at radial position r1 and covering the outer periphery of the core, a second clad layer with outermost radius r3 adjacent to the first clad layer at radial position r2 and covering the outer periphery of the first clad layer, and a third clad layer adjacent to the second clad layer at radial position r3 and covering the outer periphery of the second clad layer. The refractive index of the first clad layer decreases continuously from the inside to the outside, reaching a maximum value at radial position r1 and a minimum value at radial position r2. The refractive index of the second clad layer increases continuously from the inside to the outside, reaching a minimum value at radial position r2 and a maximum value at radial position r3.

The present disclosure provides systems and methods for preventing or minimizing optical crosstalk in an optical circuit switch (“OCS”). The OCS may include a collimator lens assembly. The collimator lens assembly may include a lens array defined by a plurality of ports. Each port may include a lenslet and a spacer paired with each lenslet. Crosstalk may occur when light from other ports enter the target port's optical fiber. The collimator lens assembly may include an insert positioned relative to the lenslet. The insert may define an aperture that allows light from the target port to pass through. The insert may prevent a portion of light from adjacent ports from passing through the aperture. The insert may be located between the lenslet and spacer, on the curved surface of the lenslet, or on a plate located at a distance from the front of the lenslet.

A display module includes an image light generation device, a light-guiding member, a first reflection surface configured to reflect the imaging light incident via the light-guiding member, a first diffraction element configured to diffract the imaging light, and a second diffraction element configured to diffract the image light and form an exit pupil. The image light is sequentially incident on a first deflection surface, a second deflection surface, a second reflection surface, a third reflection surface, a fourth reflection surface, and a third deflection surface inside the light-guiding member, and a distance from a reference position where an optical axis of the exit pupil and an emission surface intersect to the second deflection surface is longer than a distance from the reference position to the first deflection surface and longer than a distance from the reference position to the second reflection surface.

A combiner includes: an input fiber bundle including input fibers; and a bridge fiber including a GI fiber section. A beam bundle emitted from the input fiber bundle enters the GI fiber section, the bridge fiber has a diameter smaller at an exit end surface of the bridge fiber than at an entrance end surface of the bridge fiber, and the GI fiber section converges the beam bundle.

There are provided: a plurality of optical elements for handling light having different wavelengths; a plurality of collimating lenses individually provided in the optical elements, each of the collimating lenses having a first end facing a main surface of one of the optical elements; an optical multi-demultiplexer using reflection of light caused by a spatial optical system, the optical multi-demultiplexer having a first end facing a second end of each of the collimating lenses; a coupling lens having a first end facing a second end of the optical multi-demultiplexer; an SMF having one end facing a second end of the coupling lens; and an optical block, which is transparent, provided on an optical path between each of the collimating lenses and the optical multi-demultiplexer, the optical path having a small number of reflections in the optical multi-demultiplexer.

A head-up display (1) has a housing (2) with a housing lower part (3) and a housing upper part (4). The housing upper part (4) has a cover pane (5) designed for a projection. The housing (2) can be fastened to a body component (11) via a fastening system (7) that forms form a releasable connection both to the housing (2) and to the body component (11). The fastening system (7) has first passage openings (17) for the installation on the housing (2) and second passage openings (19) for the installation on the body component (11). The passage openings (17, 19) are elongated holes that receive pin-shaped fixing elements (8) to achieve the connection to the housing (2) and to the body component (11). An installation gauge for a head-up display and a gauging method for a head-up display also are provided.

A light fixture for lighting a surface includes a housing, a plurality of light sources, and a molded optic through which light from the light sources is directed. The molded optic further includes a plurality of concave aspheric optical surfaces in a first side of the molded optic, each of the concave aspheric optical surfaces partially enclosing one or more of the plurality of light sources, wherein the aspheric concave optical surfaces receive light directly from the respective light sources, and a plurality of convex aspheric optical surfaces disposed respectively opposite the plurality of concave aspheric optical surfaces on a second side of the molded optic, opposite the first side. The light sources and the aspheric optical surfaces cooperate to direct light onto the surface in an illumination field that is generally rectangular.

A hologram recording device for producing a hologram that diffracts incident light includes: a laser light source; a first half-wave plate that controls a polarization direction of a light beam emitted from the laser light source; a polarizing beam splitter that reflects S-polarized light to emit the S-polarized light as an A light ray and transmits P-polarized light to emit the P-polarized light as a B light ray with respect to the light beam passing through the first half-wave plate, and splits the light beam in two directions; a first wedge prism mirror that reflects the A light ray; a second half-wave plate that polarizes the B light ray into S-polarized light; a second wedge prism mirror that reflects the S-polarized light polarized by the second half-wave plate; and a recording medium irradiated with light rays reflected by the first wedge prism mirror and the second wedge prism mirror.