Topic
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.
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TL;DR: In this paper, a Mach-Zehnder interferometer is built by two mechanically-induced long-period gratings and a fiber taper in the middle section is inserted.
Abstract: A Mach–Zehnder interferometer formed in single mode fiber is implemented. The interferometer is built by two mechanically-induced long-period gratings. In addition, a fiber taper in the middle section is inserted. The spectral properties of the whole system are analyzed. Visibility of the interference fringes up to 0.80 (the higher ever reported using mechanically-induced long-period gratings) with fringe spacing in the 4.1 to 0.86 nm range are experimentally demonstrated. The proposed device allows reducing the fiber diameter of the section between gratings with a minimal effect in the interference fringe spacing. The sensitivity of the interferometer to external refractive index changes was also studied. It is experimentally shown that, due to the nature of the cladding mode excited, it is necessary to taper the fiber to improve the system sensitivity to external refractive index. Fiber tapers with different diameter, inserted between the long-period gratings pair were fabricated and tested for measuring external refractive index changes. A maximum resolution of 2.3×10−4 RIU in a refractive index range from 1.36 to 1.402 is achieved.
31 citations
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11 Sep 1972TL;DR: In this article, the faster propagating, higher order modes are selectively removed from a multimode optical fiber by either attenuating said modes or coupling the modes out of the fiber core and into the surrounding cladding.
Abstract: The faster propagating, higher order modes are selectively removed from a multimode optical fiber by either attenuating said modes or by coupling the modes out of the fiber core and into the surrounding cladding. In one embodiment the fiber core is surrounded by a low-loss cladding of prescribed thickness, and a refractive index that is no greater than that of any portion of the core. In an alternate embodiment, the core is surrounded by a low-loss cladding whose refractive index is greater than that at the periphery of the core.
31 citations
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07 Jun 1996
TL;DR: In this article, a polymeric optical component having an at least penta-layered polymer structure on a substrate comprising: A) a low refractive index lower cladding layer, B) a core-matching lower claddings layer, C), a core layer, D, a corematching upper clatterers layer, and E) a lower refractive indices upper cladderers layer is presented.
Abstract: The present invention is in the field of optical components, more particularly, polymeric optical components, even more particularly, thermo-optical components, electro-optical components or passive components. The present invention pertains to an optical component having an at least penta-layered polymer structure on a substrate comprising: A) a low refractive index lower cladding layer, B) a core-matching refractive index lower cladding layer, C) a core layer, D) a core-matching refractive index upper cladding layer, and E) a low refractive index upper cladding layer. With this specific layer structure an optimal transversal confinement can be obtained, which results in less loss of light and an improved switching efficiency.
31 citations
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25 Apr 2014TL;DR: In this paper, the authors describe scratch-resistance and improved optical properties of articles that exhibit a color shift of about 2 or less, when viewed at an incident illumination angle in the range from about 0 degrees to about 60 degrees from normal under an illuminant.
Abstract: Embodiments of this disclosure pertain to articles that exhibit scratch-resistance and improved optical properties. In some examples, the article exhibits a color shift of about 2 or less, when viewed at an incident illumination angle in the range from about 0 degrees to about 60 degrees from normal under an illuminant. In one or more embodiments, the articles include a substrate, and an optical film disposed on the substrate. The optical film includes a scratch-resistant layer and a refractive index gradient. In one or more embodiments, the refractive index includes a refractive index that increases from a first surface at the interface between the substrate and the optical film to a second surface. The refractive index gradient may be formed from a compositional gradient and/or a porosity gradient.
31 citations
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24 Apr 2000TL;DR: In this article, a dispersion compensating optical fiber that includes a core surrounded by a cladding layer of refractive index nCL is presented, where the core includes at least three radially adjacent regions, a central core region, a moat region and a ring region.
Abstract: Disclosed is a dispersion compensating optical fiber that includes a core surrounded by a cladding layer of refractive index nCL. The core includes at least three radially adjacent regions, a central core region, a moat region having a refractive index nM that is sufficiently lower than nCL such that ΔM ≤ -0.4 %, and a ring region. As the ring region exhibits sufficiently high refractive index at a sufficiently long distance from the outer edge of the moat region, the fiber can exhibit low values of negative dispersion slope at low values of negative dispersion and yet exhibit good bending loss. This ring region is also capable of imparting to the fiber a relatively high cutoff wavelength, so that the present invention is particularly well suited for use in L-band systems. A particularly suitable fiber has an index profile in which that part of the ring region at the transition between the moat and the ring region has a refractive index such that its delta value is close to zero. Also disclosed is a method of forming the fiber of the present invention.
31 citations