Electro-optic (EO) devices having an EO polymer core comprising a first host polymer and a first nonlinear optical chromophore (NLOC); and a cladding comprising a second host polymer and a second NLOC, and methods of preparing the same; wherein the first NLOC has a first bridge covalently bonded to an electron-accepting group and an electron-donating group; wherein the second NLOC has a second bridge covalently bonded to an electron-accepting group and an electron-donating group; and wherein the second bridge is less conjugated than the first bridge such that the cladding has an index of refraction that is less than that of the EO polymer core, and wherein the second NLOC is present in the second host polymer in a concentration such that the cladding has a conductivity equal to or greater than at least 10% of the conductivity of the EO polymer core at a poling temperature.

An optical-waveguide-clad composition includes a bisphenol type epoxy compound (A), and an epoxy compound (B) containing, in a molecule, at least one of a structure represented by the following formula (1) and a structure represented by the following formula (2), and having a molecular weight of 350 or higher.

##STR00001##

In the formula (1), R.sub.1 and R.sub.2 each independently represent a hydrogen atom or an alkyl group, and m represents 2 to 15.

##STR00002##

In the formula (2), R.sub.3 and R.sub.4 each independently represent a hydrogen atom or an alkyl group, and n represents 2 to 15.

An optical-waveguide-clad composition includes a bisphenol type epoxy compound (A), and an epoxy compound (B) containing, in a molecule, at least one of a structure represented by the following formula (1) and a structure represented by the following formula (2), and having a molecular weight of 350 or higher.

##STR00001##

In the formula (1), R.sub.1 and R.sub.2 each independently represent a hydrogen atom or an alkyl group, and m represents 2 to 15.

##STR00002##

In the formula (2), R.sub.3 and R.sub.4 each independently represent a hydrogen atom or an alkyl group, and n represents 2 to 15.

An athermal optical waveguide structure such as an optical add drop multiplexer (OADM) or the like is fabricated by a method that includes forming a lower cladding layer on a substrate. A waveguiding core layer is formed on the lower cladding layer. An upper cladding layer is formed on the waveguiding core layer and the lower cladding layer a sol-gel material. The sol-gel material includes an organically modified siloxane and a metal oxide. A thermo-optic coefficient of the sol-gel material is adjusted by curing the sol-gel material for a selected duration of time at a selected temperature such that the thermo-optic coefficient of the sol-gel material compensates for a thermo-optic coefficient of at least the waveguiding core layer such that an effective thermo-optic coefficient of the optical waveguide structure at a specified optical wavelength and over a specified temperature range is reduced.

An athermal optical waveguide structure such as an optical add drop multiplexer (OADM) or the like is fabricated by a method that includes forming a lower cladding layer on a substrate. A waveguiding core layer is formed on the lower cladding layer. An upper cladding layer is formed on the waveguiding core layer and the lower cladding layer a sol-gel material. The sol-gel material includes an organically modified siloxane and a metal oxide. A thermo-optic coefficient of the sol-gel material is adjusted by curing the sol-gel material for a selected duration of time at a selected temperature such that the thermo-optic coefficient of the sol-gel material compensates for a thermo-optic coefficient of at least the waveguiding core layer such that an effective thermo-optic coefficient of the optical waveguide structure at a specified optical wavelength and over a specified temperature range is reduced.

A method of fabricating a multi-core polymer optical fibre comprises arranging optical fibre preforms in a stack, the optical fibre preforms each comprising a polymer core and polymer cladding surrounding the polymer core; and drawing and bonding the stack to form the multi-core polymer optical fibre. Any contaminants or impurities which collect on outer surfaces of the preforms may be confined to boundaries between the preforms, which may avoid attenuation of signals passed through the cores while at the same time reducing crosstalk between cores of the final manufactured fibre. Also provided is a multi-core polymer optical fibre obtainable by the method.

A method of fabricating a graded-index polymer optical fibre comprises preparing a cladding composition, the cladding composition comprising either a mixture of a cladding polymer and a dopant or a mixture of a cladding polymer precursor and a dopant; forming cladding from the cladding composition around a core, the core comprising a core polymer; and causing diffusion of the dopant into the core such that the dopant has a continuous concentration gradient, according to which concentration gradient the concentration of the dopant increases with radial distance from a centre of the core. The dopant is a compound having a refractive index which is lower than a refractive index of the core polymer. By distributing the dopant such that the dopant concentration is lowest at the centre of the core, the optical attenuation of the graded-index polymer optical fibre may be reduced. Also provided is a graded-index polymer optical fibre obtainable by the method.

In some embodiments, a head-mounted augmented reality display system comprises one or more hybrid waveguides configured to display images by directing modulated light containing image information into the eyes of a viewer. Each hybrid waveguide is formed of two or more layers of different materials. The thicker of the layers is a highly optically transparent “core” layer, and the thinner layer comprises a pattern of protrusions and indentations to form, e.g., a diffractive optical element. The pattern may be formed by imprinting. The hybrid waveguide may include additional layers, e.g., forming a plurality of alternating core layers and thinner patterned layers. Multiple waveguides may be stacked to form an integrated eyepiece, with each waveguide configured to receive and output light of a different component color.

A method of making a daylight redirecting window film having a layered structure with a total thickness of less than one millimeter and having at least two optical films bonded together. One of the optical films has a first light redirecting layer disposed on a first side of the film and including a linear array of light redirecting structures configured to reflect light using a total internal reflection and defining a parallel array of narrow channels, and a second light redirecting layers disposed on an opposite second side of the film and including light scattering surface microstructures. The method includes coating a surface of at least one of the films with an optical adhesive, positioning the optical films such that the top portions of the light redirecting structures face inwards, and bonding the films together to form a monolithic multi-layer light redirecting film structure.

Disclosed is an optical waveguide, for transmitting a guided optical light beam having a wavelength >180 nm, including a core for guiding light made of a first material having a first index of refraction, and a cladding including a thermoplastic elastomer, the innermost layer of the cladding having a refractive index smaller than the refractive index of the outermost layer of the core. Also disclosed is a medical device and waveguide sensors including the optical waveguide, as well as a method of fabrication of the optical waveguide. The method is based on the realisation of a full thermoplastic elastomer preform or a preform having a central aperture. Before or after elongating the preform to a predetermined length and a predetermined lateral dimension, the core of the preform is filled and hardened so as to provide such optical waveguide. Also described is a 3D printing method to realize the preform.