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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, an optical diffraction method is exploited to characterize periodically poled MgO-doped congruent LiNbO3 crystal fabricated by electric induced technique.
Abstract: An optical diffraction method is exploited to characterize periodically poled MgO-doped congruent LiNbO3 crystal fabricated by electric induced technique. The optical diffraction patterns indicate that the refractive index changes occur in periodic domain structures. Light diffraction from this type of refractive index modulation is simulated, thus providing an effective and nondestructive technique to determine the refractive index changes and domain structures. From the normalized diffraction intensity, we estimate the refractive index change to be in the magnitude of 10−5.
21 citations
Patent•
15 Mar 2013
TL;DR: In this paper, the authors describe modified step index and GRaded INdex (GRIN) fibers with low core relative delta (near 0.8%) which have desirable properties for transmission.
Abstract: The specification describes modified step index and GRaded INdex (GRIN) fibers with low core relative delta (near 0.8%) which have desirable properties for transmission. These lower delta fibers have lower attenuation losses due to reduced Rayleigh scattering, which is desirable to improve performance in multiple mode multiplexing. The fiber designs include optimized raised triangle profiles, and depressed cladding profiles, to support two and four LP modes.
21 citations
Patent•
23 Jul 1998TL;DR: In this article, a band-pass filter formed in an optical waveguide, provided with a diffraction grating group having a period Λ of refractive index fluctuation changing in an axial direction with substantially a constant changing width Δn, comprises two periodic variable areas having periodes Λ different from each other; a zero area, disposed therebetween, having a constant refractive indices.
Abstract: A band-pass filter formed in an optical waveguide, provided with a diffraction grating group having a period Λ of refractive index fluctuation changing in an axial direction with substantially a constant changing width Δn, comprises two periodic refractive index variable areas having periodes Λ different from each other; a zero area, disposed therebetween, having substantially a constant refractive index; and boundary areas, disposed between the zero area and the respective periodic refractive index variable areas, in which the changing width of refractive index monotonously changes between 0 and Δn.
21 citations
Patent•
01 Dec 2010
TL;DR: In this article, a high bandwidth multimode fiber with a core layer and cladding layers is proposed, where the core layer has a parabola radius of 15-35 mm and the maximum relative refractive index difference Δ1%max satisfies Δ 1%max>0.8%.
Abstract: A high bandwidth multimode fiber comprises a core layer and cladding layers. The radius of the core layer is 15~35 mm, the refractive index profile of the core layer is a parabola, and the maximum relative refractive index difference Δ1%max satisfiesΔ1%max>0.8%. The cladding layers outside the core layer comprise an inner cladding layer and/or a sunken inner cladding layer, a rising ring and a sunken outer cladding layer from the inside to the outside in turn, and the relative refractive index difference of each layer satisfies these relations as follows: Δ1%max>Δ2%>Δ3%, Δ4%>Δ3%, Δ4%>Δ5%, and Δ4%>Δ2%. The high bandwidth multimode fiber reduces the additional attenuation of the fiber macro-bending, and improves the anti-bending performance of the fiber. The fiber is provided with the rising ring, so that the energy of some high-order modes of the core layer of the fiber is transferred or coupled to some modes of the rising ring from the core layer, and therefore the bandwidth of the bending-insensitive multimode fiber is effectively improved.
21 citations
Patent•
13 Mar 1996
TL;DR: In this paper, the authors defined a region defined by at least a stress-relieving intermediate portion (30) disposed between core (10) and the optical cladding (20), which was defined to provide an increase in the cutoff wavelength and a thermal expansion coefficient and a viscosity adequate to reduce the internal stress levels at least in core(10) of the optical waveguide.
Abstract: Optical waveguide of the type comprising a core (10) presenting a refractive index (n1), maximal at least at its center; an optical cladding (20) involving core (10) and presenting a refractive index (n2) constant along its diametral extension and lower than the maximum refractive index (n1) of core (10) and further including a region defined by at least a stress-relieving intermediate portion (30) disposed between core (10) and the optical cladding (20), said intermediate portion presenting: a refractive index (n3), maximal along its diametral extension, at the maximum equal to the refractive index (n1) of core (10) and at least equal to refractive index (n2) of optical cladding (20), so as to provide an increase in the cutoff wavelength; a thermal expansion coefficient and a viscosity adequate to reduce the internal stress levels at least in core (10) of the optical waveguide to values which permit the obtention of acceptable attenuation and chromatic dispersion for a wavelength region.
21 citations