16 results about "Refractive index contrast" patented technology

The invention discloses a tunable band elimination filter based on a quantum well structure photon time crystal and a method. The tunable band elimination filter comprises the quantum well structure photon time crystal; the quantum well structure photon time crystal comprises a first photon time crystal section, a time domain quantum well section and a second photon time crystal section which are connected in sequence; when an electromagnetic signal is propagated, the electromagnetic signal sequentially passes through the first photon time crystal section, the time domain quantum well section and the second photon time crystal section, so that a stable band gap region and a controllable resonance response are formed in a momentum space; a fitting relation between a local state equivalent wave vector and a time structure parameter is established by adjusting a time section proportion parameter and a refractive index contrast ratio in a quantum well structure photon time crystal, so that the local state quantity and momentum position of an electromagnetic signal are regulated and controlled; and frequency spectrum regulation of the electromagnetic signal is realized through a corresponding relation between the momentum space and the frequency domain space. The frequency spectrum regulation and control precision and the system stability are improved.

Embodiments described herein relate to encapsulated optical devices and methods of forming optical devices with controllable air-gapped encapsulation. In one embodiment, a plurality of openings are formed in a support layer surrounding the plurality of optical device structures to create a high refractive index contrast between the optical device structures, the support layer, and the openings. In another embodiment, sacrificial material is disposed in-between the optical device structures and then an encapsulation layer is disposed on the optical device structures. The sacrificial material is removed, forming a space bounded by the encapsulation layer, the substrate, and each of the optical device structures. In yet another embodiment, the encapsulation layer is disposed over the optical device structures forming a space bounded by the encapsulation layer, the substrate, and each of the optical device structures.

The present invention provides a novel optical waveguide configuration in which the impact of a fabrication error on optical circuit characteristics is suppressed, while reducing the size of of a waveguide with a high refractive index contrast and maintaining characteristics such as a stable refractive index. An optical circuit according to the present disclosure comprises an optical waveguide that achieves characteristic optical confinement. The optical waveguide includes: a slab-shaped first core; and a second core having a rectangular cross-section. By suppressing the amount of change in the refractive index in directions parallel and perpendicular to the substrate surface, the impact of a manufacturing error on the optical circuit characteristics is mitigated. It is also possible to suppress propagation loss since most of the optical power is confined in the slab-shaped first core, which does not require patterning.

The present disclosure provides a photonic system, comprising: a PIC comprising a first SiN waveguide; and a second SiN waveguide vertically tapered by increasing thickness in a direction towards the first SiN waveguide and vertically tapered by decreasing thickness in a direction away from the first SiN waveguide, wherein: the first SiN waveguide comprises a tapered end having a first effective index n1; and the second SiN waveguide and a third SiN waveguide together form first and second low-index contrast sections of an effective index n2 at the ends, a third high-index contrast section between the first and second low-index contrast sections, the third high-index contrast section having a third effective index n3 and a vertical taper that adiabatically couples the first and second low-index contrast sections to the third high-index contrast section, n3 is close to n1 and n3 > n2, and the tapered end of the first SiN waveguide is optically coupled to the third high-index contrast section.

An optical metasurface film includes a flexible polymeric film having a first major surface, a patterned polymer layer having a first surface proximate to the first major surface of the flexible polymeric film and having a second nanostructured surface opposite the first surface, and a refractive index contrast layer including a refractive index contrast material adjacent to the nanostructured surface of the patterned polymer layer forming a nanostructured bilayer with a nano structured interface. The nanostructured bilayer comprising a plurality of nanostructures disposed on the flexible polymeric film. The nanostructured bilayer imparts a light phase shift that varies as a function of position of the nano structured bilayer on the flexible polymeric film. The light phase shift of the nanostructured bilayer defines a predetermined operative phase profile of the optical metasurface film. A light reflecting layer is in optical communication with the nano structured bilayer.

The invention provides a double-layer silicon nitride grating coupler for a visible light wave band. The double-layer silicon nitride grating coupler comprises a substrate, a lower cladding, a first layer of silicon nitride, an interlayer, a second layer of silicon nitride and an upper cladding from bottom to top, the first layer of silicon nitride comprises a first layer of silicon nitride grating and a silicon nitride waveguide, and the second layer of silicon nitride is a second layer of silicon nitride grating and is output by the lower layer of silicon nitride waveguide, so that relatively high coupling efficiency is realized. Due to the visible light wave band, the thickness of the first layer of silicon nitride and the second layer of silicon nitride does not exceed 500nm. According to the double-layer silicon nitride grating coupler, the vertical symmetry of gratings is broken through, high-directivity propagation of light waves is achieved through proper position arrangement of the two layers of silicon nitride gratings, and meanwhile the refractive index contrast ratio and the coupling efficiency can be improved through the double-layer gratings; on the premise that the grating period is not affected, the technology of the double-layer silicon nitride grating coupler manufactured based on the two uniform fully-etched gratings is simple.

This invention discloses a high-refractive-index contrast radiation-cooling coating, belonging to the technical field of radiation-cooling coatings. The raw materials of this invention's high-refractive-index contrast radiation-cooling coating include hollow microspheres, high-refractive-index pigments, film-forming substances, solvents, and additives. The coating process of this invention's radiation-cooling coating is a two-coat process. First, an inner coating is applied to the substrate surface using the radiation-cooling coating with rutile titanium dioxide as the high-refractive-index pigment. Then, an outer coating is applied to the surface of the inner coating using the radiation-cooling coating with zirconium dioxide and / or zirconium silicate as the high-refractive-index pigments. This invention introduces a closed, independent bubble structure into the coating using hollow microspheres, combined with a preferred high-refractive-index pigment, to increase the refractive index difference between adjacent components in the coating, significantly enhancing its solar reflectance, thereby achieving excellent radiation-cooling performance under strong sunlight.

A photonic device including a first waveguide and a second waveguide is provided. The device includes an interconnect coupled with the first waveguide and the second waveguide. The interconnect includes a substrate. The interconnect includes a film including a refractive index contrast (RIC) polymer and a core. The core includes a first domain having a first refractive index. The core includes a second domain adjacent to the first domain and having a second refractive index. The second refractive index is less than the first refractive index. The core includes a third domain adjacent to the second domain and having a third refractive index. The third refractive index is less than the second refractive index. The second domain is disposed between the first domain and the third domain. The refractive index of the substrate is less than the first refractive index, the second refractive index, and the third refractive index.

The invention discloses a femtosecond laser manufacturing method of a total positive refractive index or total negative refractive index change optical waveguide in a single crystal, and relates to the technical field of integrated photons. The method specifically comprises the following steps: adjusting the transverse intensity distribution of a femtosecond laser beam through a slit shaping and oil-immersed objective lens technology to obtain a shaped femtosecond laser beam, and then focusing the femtosecond laser beam into a transparent single crystal material; a positive refractive index change area is constructed to form a waveguide core layer in similar photonic crystal arrangement or a negative refractive index change area is constructed to form a waveguide cladding in similar photonic crystal arrangement through a mode of multiple femtosecond laser direct writing, and then a Type-I type core layer waveguide or a Type-II type cladding waveguide is formed. By adopting the method disclosed by the invention, the waveguide with high refractive index contrast ratio, high precision and low loss is formed in the transparent single crystal material, and the section of the waveguide can be customized into any shape. The method is suitable for various active / passive transparent single crystal materials, and has a wide application prospect in the fields of integrated optical amplifiers and light quantum chips.

A self-mixing interferometric, SMI, laser sensor comprises a vertical cavity surface emitting laser, VCSEL, configured to emit laser radiation, the VCSEL comprising a first distributed Bragg reflector, DBR, a second DBR and a cavity region including an active light generation region, wherein the cavity region is arranged in a layer structure between a front side of the first DBR and a back side of the second DBR. Therein at least one of the first and second DBR comprises a first contrast region and a second contrast region, the first contrast region having a first refractive index contrast Δn1 regarding an emission wavelength of the VCSEL and the second contrast region having a second refractive index contrast Δn2 / n larger than the first refractive index contrast Δn1 / n.

The invention relates to a nonvolatile reconfigurable mode converter and a preparation method thereof. The mode converter comprises a first waveguide and a second waveguide, a plurality of phase change materials are deposited on the first waveguide and the second waveguide respectively, and the states of the phase change materials are controlled respectively to achieve conversion from a fundamental mode to different high-order modes. According to the invention, the conversion among a plurality of different modes can be realized only by using a single device, the utilization rate of the device is improved, the design and manufacturing cost of the device is obviously reduced, and the expandability is realized; the phase-change material has non-volatility, so that the power consumption of the device can be remarkably reduced; reconfigurability of the device is achieved through reversible phase change of the phase change material, and due to the fact that the refractive index contrast ratio between the crystalline state and the amorphous state of the phase change material is large, the size of the device can be remarkably reduced, and the integration level of a photon chip is improved.

An organic photovoltaic device comprises a first electrode, at least one organic heterojunction layer positioned over the first electrode, a second electrode positioned over the organic heterojunction layer, and a thin film stack positioned over the second electrode, comprising a plurality of sublayers of a first dielectric material alternating with a plurality of sublayers of a second dielectric material, wherein at least one of the plurality of sublayers of the first dielectric material has a thickness that is different from another of the plurality of sublayers of the first dielectric material, wherein the organic photovoltaic device has a mean transmittance of between 10% and 100% for light between 420 nm and 670 nm, with a variance of ±10%, and wherein an index contrast between the sublayers in the thin film stack is at least 0.1. A method of fabricating an organic photovoltaic device is also disclosed.

An integrated sensor includes a substrate made of a first semiconductor material having a first optical refractive index. The substrate includes a pixel array, wherein each pixel has a photosensitive active zone formed by an index contrast zone including a matrix of the first semiconductor material and a periodic structure embedded in the matrix. The periodic structure extends from the backside of the substrate and has a two-dimensional periodicity in a parallel plane with the backside. A value of the periodicity is linked with the wavelength of the optical signal and with the first refractive index. Elements of the periodic structure are formed of a second optically transparent material having a second refractive index less than the first refractive index. These elements are positioned at locations defined by the periodicity except for at one location defining a region, preferably central, that is devoid of a corresponding one of the elements.

To provide an optical waveguide device in the field of mid-infrared photonics and a method for manufacturing such a device.SOLUTION: The device comprises a fluoride glass substrate having a local concentration of a chemical element at an internal contact and a waveguide inscribed along a path defined in the substrate. The waveguide is formed by directing a focused ultra-short laser pulse into the substrate and scanning the pulse to induce migration and densification of chemical elements at the inner contacts, resulting in a positive refractive index contrast. Fluoride glass substrates can include zirconium fluoride and modifiers such as barium fluoride, aluminum fluoride, and rare earth elements to enable optical gain. The described technology further encompasses an integrated photonics device including a waveguide laser with mirrors and gratings defining a laser cavity for use in sensing, communications, and laser systems.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of functional thin film materials, and particularly relates to an entropy stabilizing material with a high optical quality factor and a preparation method of the entropy stabilizing material. In order to solve the problem that in the prior art, a high-symmetry crystal system is difficult to form due to strong orbital hybridization of a material in a middle-infrared band, so that low refractive index contrast ratio and low extinction coefficient of a phase change material are difficult to consider at the same time, the invention provides a light element and heavy element synergistic high-entropy doping strategy, and light elements Si and Ge and a heavy element Te are jointly introduced into a Sb2Se3 system, so that the phase change material has high refractive index contrast ratio and low extinction coefficient. And the high-entropy phase change material Si < x > Ge < y > Sb < 1-x-y > Se < 1-y > Tez is successfully prepared. The material is converted into a high-symmetry cubic structure from a low-symmetry orthogonal structure under high configuration entropy driving, p-track alignment is achieved, the optical quality factor of the material is greatly improved compared with that of traditional Ge2Sb2Te5, the material bottleneck of near-infrared and middle-infrared band all-optical memory computing image processors is broken through, and the application prospect is wide. And a key material basis is provided for practical application of the system in an intelligent visual system.

The present disclosure relates to an optical waveguide device and a method for fabricating such a device in the field of mid-infrared photonics. The device comprises a fluoride glass substrate having localized concentrations of a chemical element at inscription points, with a waveguide inscribed along a defined path within the substrate. The waveguide is formed by directing focused ultrashort laser pulses into the substrate and scanning the pulses to induce migration and densification of the chemical element at the inscription points, resulting in a positive refractive index contrast. The fluoride glass substrate may include zirconium fluoride and modifiers such as barium fluoride, aluminium fluoride, and rare-earth elements to enable optical gain. The described technology further encompasses integrated photonic devices, including waveguide lasers comprising mirrors and gratings that define a lasing cavity for use in sensing, communication, and laser systems.