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49results about How to "Effective refractive index" patented technology

Interferometer and its fabrication method

An interferometer includes a waveguide core, and thin film heaters with widths W1 and W2. The thin film heaters are mounted directly above the waveguide core, and operate as two types of different annealing regions. The annealing, which is carried out by supplying current to the thin film heaters, can alter the quality of the cladding, and change the stress applied on the waveguide core, thereby making it possible to control the polarization dependency. Thus changing the width of the thin film heaters and / or the amount of the supply current thereto enables the permanent control of the effective refractive index (birefringence index) independently in the transverse electric polarization mode and the transverse magnetic polarization mode. This enables the transverse electric polarization mode to be adjusted to a phase difference of .lambda. / 2, and the transverse magnetic polarization mode to a phase difference of zero.
Owner:NIPPON TELEGRAPH & TELEPHONE CORP

Tunable resonant grating filters

A tunable resonant grating filter that can reflect optical radiation at a resonant wavelength, the resonant wavelength being selectively variable. The filter includes a diffraction grating, a planar waveguide, and a light transmissive material having a selectively variable refractive index to permit tuning of the filter, the light transmissive material forming a tunable cladding layer for the waveguide, preferably a liquid crystal material. The diffraction grating is placed on the opposite side of the tunable layer with respect to the planar waveguide, thereby making it possible to tailor the grating structural parameters to the desired bandwidth of the filter response without significantly affecting the tunability of the filter. Within the resonant structure, the core layer, i.e., the waveguide, can be placed close to the tunable layer either in direct contact with the tunable layer or with an interposed relatively thin intermediate layer(s) between the core and the tunable layer.
Owner:PIRELLI & C

Method of varying optical properties of photonic crystals on fast time scales using energy pulses

The present invention provides a method for fast switching of optical properties in photonic crystals using pulsed / modulated free-carrier injection. The results disclosed herein indicate that several types of photonic crystal devices can be designed in which free carriers are used to vary dispersion curves, stop gaps in materials with photonic bandgaps to vary the bandgaps, reflection, transmission, absorption, gain, or phase. The use of pulsed free carrier injection to control the properties of photonic crystals on fast timescales forms the basis for all-optical switching using photonic crystals. Ultrafast switching of the band edge of a two-dimensional silicon photonic crystal is demonstrated near a wavelength of 1.9 μm. Changes in the refractive index are optically induced by injecting free carriers with 800 nm, 300 fs pulses. Band-edge shifts have been induced in silicon photonic crystals of up to 29 nm that occurs on the time-scale of the pump pulse. The present invention also provides a method of producing a virtual or temporary photonic crystal using free carrier injection into pure semiconductors, bulk or thin film, in which the carriers are generated in patterns which create a patterned refractive index contrast used to steer light beams in the semiconductor while it is being pulsed.
Owner:LEONARD STEPHEN W +5

Transparent conductors that exhibit minimal scattering, methods for fabricating the same, and display devices comprising the same

Transparent conductors that exhibit minimal scattering, methods for fabricating such transparent conductors, and display devices comprising such transparent conductors are provided. In one exemplary embodiment, a transparent conductor comprises a substrate having an effective refractive index n1, an over layer overlying the substrate and having an effective refractive index n3, and a transparent conductive coating interposed between the substrate and the over layer. The transparent conductive coating comprises a plurality of conductive components and a matrix material that together have an effective refractive index n2 in the range of about √{square root over (n1×n3)}−Δ≦n2≦√{square root over (n1×n3)}+Δ, wherein Δ is an optimization factor within the range of about 0 to about 0.3.
Owner:HONEYWELL INT INC

Photochemically refractive-index-changing polymer, photochemically refractive-index-changing polymer composition, and method of refractive index regulation

A subject for the invention is to provide a method of refractive index regulation by which the refractive index of an optical polymer molding can be efficiently changed without necessitating a complicated step, such as the step of oxidizing beforehand, and which when used for producing an optical device, imparts excellent transparency thereto. Another subject is to provide a photochemically refractive-index-changing polymer or photochemically refractive-index-changing polymer composition for use in the method.
The invention relates to a method of refractive index regulation characterized in that either a photochemically refractive-index-changing polymer which is a polymer of one or more monomers comprising an acrylic vinyl monomer represented by CH2═C(R1)C(═O)O—R2═CH2 (wherein R1 is hydrogen or methyl and R2 is a saturated or unsaturated hydrocarbon group having 1-20 carbon atoms, provided that the monomer may have one or more heteroatoms and halogen atoms in the molecule) as an essential ingredient and which has radial-polymerizable side-chain vinyl groups remaining in the molecule or a composition containing this polymer is irradiated with a radiation, e.g., ultraviolet, to react the vinyl groups and thereby cause a density change so as to result in a refractive-index increase (Δn) through the irradiation of 0.005 or more.
Owner:NITTO DENKO CORP

Photochemically refractive-index-changing polymer, photochemically refractive-index-changing polymer composition, and method of refractive index regulation

A subject for the invention is to provide a method of refractive index regulation by which the refractive index of an optical polymer molding can be efficiently changed without necessitating a complicated step, such as the step of oxidizing beforehand, and which when used for producing an optical device, imparts excellent transparency thereto. Another subject is to provide a photochemically refractive-index-changing polymer or photochemically refractive-index-changing polymer composition for use in the method.The invention relates to a method of refractive index regulation characterized in that either a photochemically refractive-index-changing polymer which is a polymer of one or more monomers comprising an acrylic vinyl monomer represented by CH2═C(R1)C(═O)O—R2═CH2 (wherein R1 is hydrogen or methyl and R2 is a saturated or unsaturated hydrocarbon group having 1-20 carbon atoms, provided that the monomer may have one or more heteroatoms and halogen atoms in the molecule) as an essential ingredient and which has radial-polymerizable side-chain vinyl groups remaining in the molecule or a composition containing this polymer is irradiated with a radiation, e.g., ultraviolet, to react the vinyl groups and thereby cause a density change so as to result in a refractive-index increase (Δn) through the irradiation of 0.005 or more.
Owner:NITTO DENKO CORP
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