9 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 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.