Anti-reflective optical structures are disclosed. The anti-reflective optical structures include sub-wavelength structures in order to produce one or more index of refraction gradients within the anti-reflective optical structures. The one or more index of refraction gradients can reduce reflection of light over a broad band of wavelengths.

There is provided a photonic integrated circuit configured for low-coherence interferometry and in-field sensing. The photonic integrated circuit can include an opto-coupler that has a substrate substantially transparent to a specified wavelength of light and a waveguide configured to route a light beam having a center wavelength at the specified wavelength. The opto-coupler further includes a mirror disposed at an angle, and the mirror is disposed on an angled surface of the substrate, the angled surface being proximate to an output end of the waveguide. The opto-coupler further includes a beam forming element configured to collect light reflected from the mirror, and the waveguide and the mirror are integrated within the substrate.

Structures for an optical coupler and methods of forming an optical coupler. The structure comprises a first waveguide core including a first tapered section, a second waveguide core including a second tapered section overlapped with the first tapered section, and an active layer including a third tapered section overlapped with the second tapered section. The first waveguide core comprises a first passive material, the second waveguide core comprises a second passive material, and the active layer comprises an active material.

A photonic integrated circuit and a method for its manufacture are provided. In an embodiment, an intermetal dielectric layer, for example, a silicon oxide layer, is contiguous between an upper metal layer and a lower metal layer on a substrate. One or more waveguides having top and bottom faces are formed in respective waveguide layers within the intermetal dielectric layer between the upper and lower metal layers. There is a distance of at least 600 nm from the upper metal layer to the top face of the uppermost of the several waveguides. There is a distance of at least 600 nm from the lower metal layer to the bottom face of the lowermost of the several waveguides. The waveguides are formed of silicon nitride for longer wavelengths and alumina for shorter wavelengths. These dimensions and materials are favorable for CMOS processing, among other things.

A photonic integrated circuit and a method for its manufacture are provided. In an embodiment, an intermetal dielectric layer, for example, a silicon oxide layer, is contiguous between an upper metal layer and a lower metal layer on a substrate. One or more waveguides having top and bottom faces are formed in respective waveguide layers within the intermetal dielectric layer between the upper and lower metal layers. There is a distance of at least 600 nm from the upper metal layer to the top face of the uppermost of the several waveguides. There is a distance of at least 600 nm from the lower metal layer to the bottom face of the lowermost of the several waveguides. The waveguides are formed of silicon nitride for longer wavelengths and alumina for shorter wavelengths. These dimensions and materials are favorable for CMOS processing, among other things.

A system for optical communication comprises a waveguide (110) and an optical coupler (100). The waveguide (110) is provided with a core of higher refractive index material disposed on a substrate (204). The optical coupler (100) is used to couple light between an integrated optical waveguide (110) and an optical fiber (120) with high coupling efficiency. The optical coupler (100) comprises a first grating (104) having a first set of ridges (224) separated by a first set of trenches (220) and a second grating (108) having a second set of ridges (234) separated by a second set of trenches (230). The first grating (104) is formed in the core of the waveguide (110). The second set of ridges (234) are offset from the first set of ridges (224). A method for fabricating the optical coupler (100) is also provided.

The disclosure provides a design method of a coupling-out grating and the design method including: calculating a diffraction coupling-in angle, at which a light beam is diffracted and coupled into the optical waveguide body through the coupling-in grating, according to an angle at which the light beam is incident to the coupling-in grating, a wavelength of the light beam and a grating period of the coupling-in grating; calculating a distance between two adjacent coupling-out positions of the light beam; calculating a brightness difference rate of the light beam after being coupled out multiple times through the coupling-out grating according to the maximum diffraction efficiency of the coupling-out grating; and calculating the number of partitions of the coupling-out grating according to a length of the coupling-out grating, a sensitivity of a human eye to the light beam, the brightness difference rate, and the distance between the two adjacent coupling-out positions.

A packaged device includes an optical IC having an optical feature therein. An interconnect structure including layers of conductive features embedded within respective layers of dielectric materials overlie the optical feature. The interconnect structure is patterned to remove the interconnect structure from over the optical feature and a dielectric material having optically neutral properties, relative to a desired light wavelength(s) is formed over the optical feature. One or more electronic ICs may be bonded to the optical IC to form an integrated package.

A packaged device includes an optical IC having an optical feature therein. An interconnect structure including layers of conductive features embedded within respective layers of dielectric materials overlie the optical feature. The interconnect structure is patterned to remove the interconnect structure from over the optical feature and a dielectric material having optically neutral properties, relative to a desired light wavelength(s) is formed over the optical feature. One or more electronic ICs may be bonded to the optical IC to form an integrated package.

The disclosure provides a design method of a coupling-out grating and the design method including: calculating a diffraction coupling-in angle, at which a light beam is diffracted and coupled into the optical waveguide body through the coupling-in grating, according to an angle at which the light beam is incident to the coupling-in grating, a wavelength of the light beam and a grating period of the coupling-in grating; calculating a distance between two adjacent coupling-out positions of the light beam calculating a brightness difference rate of the light beam after being coupled out multiple times through the coupling-out grating according to the maximum diffraction efficiency of the coupling-out grating; and calculating the number of partitions of the coupling-out grating according to a length of the coupling-out grating, a sensitivity of a human eye to the light beam, the brightness difference rate, and the distance between the two adjacent coupling-out positions.