Step-index profile

About: Step-index profile is a research topic. Over the lifetime, 3104 publications have been published within this topic receiving 53199 citations.

Low loss microring resonator device

Abstract: It is disclosed a low loss micro-ring resonator device (10; 100; 10') which comprises a closed-loop resonator waveguide (2) having a first refractive index (nr), the resonator waveguide (2) defining an inner (16) and an outer region (17) by an outer curved edge (15) of the waveguide (2). The resonator waveguide is arranged on a substrate (6; 6') having a second refractive index (nb), the refractive index difference (Δn1) between the first refractive index (nr) and the second refractive index (nb) is greater than 0.3. The device (10) also comprises an upper cladding (20) covering the inner region (16) of the resonator waveguide (2) having a third refractive index (nuc); and a lateral cladding (21) in contact with the outer curved edge (15) and extending in the outer region (17), said lateral cladding (21) having a fourth refractive index (nlc), the fourth refractive index (nlc) being lower than said third refractive index (nuc). A method for reducing propagation losses of a resonator device (10; 100;10') is also described.

Refractive index measurement of high refractive index glass beads

Abstract: The refractive index of a small sphere and rod was measured by a method using the theory of rainbow that the minimum deviation angle of a single internally reflected ray from a sphere depends solely on the relative refractive index of the sample to the medium. Experimental results confirmed an accuracy of about 1%. This method is particularly suited to materials of high refractive index, because the conventional immersion method needs liquid of higher refractive index, which inevitably contains such poisonous elements as As.

Transient Coupled Heat Transfer Inside a Scattering mMedium with Graded Refractive Index

Abstract: Transient heat transfer of coupled radiation and conduction within a semitransparent parallel plane slab of absorbing-emitting-scattering gray medium with graded index is investigated. The refractive index of the medium varies continuously along the slab thickness, and both boundary surfaces are specular and semitransparent. The medium is discretized into a number of sublayers with a constant refractive index in each, in which the radiative transfer is numerically simulated using a multilayer radiative transfer model. The multilayer model is developed using a ray-tracing method based on a zonal method. Comparison of present results with previous research shows excellent agreement, which helps to verify the validity of the multilayer radiative transfer model of a medium with a graded refractive index. Effects of optical thickness, scattering albedo, and gradient of refractive index on transient thermal behavior are examined for a medium with nonlinear refractive index distributions. It is found that temperature peaks also appear in the inner regions of a graded refractive index medium with two semitransparent surfaces subjected to external radiation even though there is no convection cooling on the surfaces and the absorbing coefficient (or extinction coefficient) is spatially uniform in the medium.

Multilayered film filter

Abstract: PROBLEM TO BE SOLVED: To produce a multilayered film filter that the width of the inhibition range can be changed without changing the film material. SOLUTION: The multilayered film filter is produced by laminating two or more kinds of substances having different refractive indices. In this method, a high refractive index material H and a low refractive index material L are laminated for the design wavelength λ in such a manner that the film includes a portion where a film structure of (L1H2L3H4L5H6) laminated in this order is continuously repeated. In the aforementioned structure, L1 is a low refractive index layer consisting of L and having the optical film thickness nLd1 satisfying 0.2×λ<=nLd1<=0.3×λ, H2 is a high refractive index layer consisting of H and having the optical film thickness nHd2 satisfying 0.025×λ<=nHd2<=0.05×λ, L3 is a low refractive index layer consisting of L and having the optical film thickness nLd3 satisfying 0.25×λ<=nLd3<=0.05×λ, H4 is a high refractive index layer consisting of H and having the optical film thickness nHd4 satisfying 0.2×λ<=nHd4<=0.3×λ, L5 is a low refractive index layer consisting of L and having the optical film thickness nLd5 satisfying 0.025×λ<=nLd5<=0.05×λ, and H6 is a high refractive index layer consisting of H and having the optical film thickness nHd6 satisfying 0.025×λ<=nHd6<=0.05×λ.

Determination of two-dimensional optical waveguide index distribution function parameters from effective indexes

Abstract: The method described is based on the least-squares method and gives the maximum-likelihood estimate of the parameters. Its practicality is demonstrated by application to waveguides with three types of refractive index distribution. First, the convergence of the method is shown by computer simulations of a waveguide with an exponential refractive index distribution. Second, a Ti-diffused LiNbO/sub 3/ waveguide is considered as an example of a Gaussian refractive index distribution. The computed refractive index distribution agrees with computational results obtained by S. Fouchet et al. (1987). Third, a proton-exchanged LiNbO/sub 3/ waveguide is considered as an example of a step refractive index distribution. The computed depth of the waveguide agrees with the measured depth. >