An optical inspection circuit includes an optical circuit to be inspected formed on a substrate, an input optical waveguide optically connected to the optical circuit, and an output optical waveguide optically connected to the optical circuit. The input optical waveguide is connected with a grating coupler for input. The grating coupler is connected with the input optical waveguide via a spot size conversion unit. The output optical waveguide is optically connected with a photodiode.

An optical inspection circuit includes an optical circuit to be inspected formed on a substrate, an input optical waveguide optically connected to the optical circuit, and an output optical waveguide optically connected to the optical circuit. The input optical waveguide is connected with a grating coupler for input. The grating coupler is connected with the input optical waveguide via a spot size conversion unit. The output optical waveguide is optically connected with a photodiode.

An optical waveguide in which a grating coupler is formed, a first pattern region arranged to surround the grating coupler, and a second pattern region arranged to surround the grating coupler are included. The first pattern region and the second pattern region are arranged adjacently. In a periphery of the grating coupler, the first pattern region is formed in a region continuous in a circumferential direction. Similarly, in the periphery of the grating coupler, the second pattern region is formed in a region continuous in the circumferential direction.

A method and apparatus for mass production of AR diffractive waveguides. Low-cost mass production of large-area AR diffractive waveguides (slanted surface-relief gratings) of any shape. Uses two-photon polymerization micro-nano 3D printing to realize manufacturing of slanted grating large-area masters of any shape (thereby solving the problem about manufacturing of slanted grating masters of any shape on the one hand, realizing direct manufacturing of large-size wafer-level masters on the other hand, and also having the advantages of low manufacturing cost and high production efficiency). Composite nanoimprint lithography technology is employed (in combination with the peculiar imprint technique and the composite soft mold suitable for slanted gratings) to solve the problem that a large-slanting-angle large-slot-depth slanted grating cannot be demolded and thus cannot be manufactured, and realize the manufacturing of the slanted grating without constraints (geometric shape and size).

Aspects described herein include an optical apparatus comprising an input port configured to receive an optical signal comprising a plurality of wavelengths, and a plurality of output ports. Each output port is configured to output a respective wavelength of the plurality of wavelengths. The optical apparatus further comprises a first plurality of two-mode Bragg gratings in a cascaded arrangement. Each grating of the first plurality of two-mode Bragg gratings is configured to reflect a respective wavelength of the plurality of wavelengths toward a respective output port of the plurality of output ports, and transmit any remaining wavelengths of the plurality of wavelengths.

An optical coupler device comprises an optical waveguide having a first edge and an opposing second edge that extend in a direction substantially parallel to a propagation direction of an input light beam injected into the optical waveguide. A grating structure is on a portion of the optical waveguide, with the grating structure having a first side and an opposing second side. The first and second sides of the grating structure extend in the same direction as the first and second edges of the optical waveguide. An optical slab adjoins with the first side of the grating structure and is in optical communication with an output of the grating structure. The grating structure includes an array of grating lines configured to diffract the input light beam into the slab at an angle with respect to the propagation direction, such that a diffracted light beam is output from the slab.

An optical coupler device comprises an optical waveguide having a first edge and an opposing second edge that extend in a direction substantially parallel to a propagation direction of an input light beam injected into the optical waveguide. A grating structure is on a portion of the optical waveguide, with the grating structure having a first side and an opposing second side. The first and second sides of the grating structure extend in the same direction as the first and second edges of the optical waveguide. An optical slab adjoins with the first side of the grating structure and is in optical communication with an output of the grating structure. The grating structure includes an array of grating lines configured to diffract the input light beam into the slab at an angle with respect to the propagation direction, such that a diffracted light beam is output from the slab.

Disclosed are grating couplers having a high coupling efficiency for optical communications. In one embodiment, an apparatus for optical coupling is disclosed. The apparatus includes: a substrate; a grating coupler comprising a plurality of coupling gratings over the substrate, wherein each of the plurality of coupling gratings extends in a first lateral direction and has a cross-section having a middle-raised shape in a second lateral direction, wherein the first and second lateral directions are parallel to a surface of the substrate and perpendicular to each other in a grating plane; and a cladding layer comprising an optical medium, wherein the cladding layer is filled in over the grating coupler.

Disclosed are grating couplers having a high coupling efficiency for optical communications. In one embodiment, an apparatus for optical coupling is disclosed. The apparatus includes: a substrate; a grating coupler comprising a plurality of coupling gratings over the substrate, wherein each of the plurality of coupling gratings extends in a first lateral direction and has a cross-section having a middle-raised shape in a second lateral direction, wherein the first and second lateral directions are parallel to a surface of the substrate and perpendicular to each other in a grating plane; and a cladding layer comprising an optical medium, wherein the cladding layer is filled in over the grating coupler.

A device includes a grating coupler with a grating constant, two light sources, and a planar waveguide, which are configured to couple light with two different wavelengths λ.sub.1, λ.sub.2 into the waveguide. The waveguide has a waveguiding layer disposed adjacent to a substrate layer and a cover layer. The waveguiding layer has a thickness d and effective refractive indices of N(λ.sub.k, j.sub.k), wherein λ.sub.k is one of the wavelengths and j.sub.k is an order of a waveguide mode, wherein the coupled light of the wavelength λ.sub.k has a coupling angle α.sub.k into the waveguide, and wherein an amount of difference between the coupling angles is a divergence angle Δα. Guiding of waveguide modes of the order j.sub.k>0 is possible for a wavelength of the coupled light. The waveguiding layer is arranged to couple the light via the grating coupler under a divergence angle of Δα<6.