Refractive index profile
About: Refractive index profile is a research topic. Over the lifetime, 3460 publications have been published within this topic receiving 40647 citations.
Papers published on a yearly basis
TL;DR: In this paper, a detailed overview of stimulated Brillouin scattering (SBS) in single-mode optical fibers is presented, with a particular emphasis on analytical analysis of the backreflected power and SBS threshold in optical fibers with various index profiles.
Abstract: We present a detailed overview of stimulated Brillouin scattering (SBS) in single-mode optical fibers. The review is divided into two parts. In the first part, we discuss the fundamentals of SBS. A particular emphasis is given to analytical calculation of the backreflected power and SBS threshold (SBST) in optical fibers with various index profiles. For this, we consider acousto-optic interaction in the guiding geometry and derive the modal overlap integral, which describes the dependence of the Brillouin gain on the refractive index profile of the optical fiber. We analyze Stokes backreflected power initiated by thermal phonons, compare values of the SBST calculated from different approximations, and discuss the SBST dependence on the fiber length. We also review an analytical approach to calculate the gain of Brillouin fiber amplifiers (BFAs) in the regime of pump depletion. In the high-gain regime, fiber loss is a nonnegligible effect and needs to be accounted for along with the pump depletion. We provide an accurate analytic expression for the BFA gain and show results of experimental validation. Finally, we review methods to suppress SBS including index-controlled acoustic guiding or segmented fiber links. The second part of the review deals with recent advances in fiber-optic applications where SBS is a relevant effect. In particular, we discuss the impact of SBS on the radio-over-fiber technology, enhancement of the SBS efficiency in Raman-pumped fibers, slow light due to SBS and SBS-based optical delay lines, Brillouin fiber-optic sensors, and SBS mitigation in high-power fiber lasers, as well as SBS in multimode and microstructured fibers. A detailed derivation of evolutional equations in the guided wave geometry as well as key physical relations are given in appendices.
TL;DR: The authors showed that materials engineered to have negative permittivity and permeability demonstrate exotic behavior, from a negative refractive index to subwavelength focusing, demonstrating exotic behavior from negative to positive refractive indices.
Abstract: Materials engineered to have negative permittivity and permeability demonstrate exotic behavior, from a negative refractive index to subwavelength focusing.
TL;DR: In this paper, a periodic sine modulation of the refractive index profile in fiber Bragg gratings (FBGs) was demonstrated with multiple equally spaced and identical wavelength channels.
Abstract: Through a periodic sine modulation of the refractive index-profile in fiber Bragg gratings (FBGs), we demonstrate gratings with multiple equally spaced and identical wavelength channels. We show 10-cm-long gratings with 4, 8, and 16 identical uniform wavelength channels separated by the ITU spacing of 100 GHz and a 22.5-cm-long grating with four identical dispersion compensating channels with a 200-GHz separation designed to dispersion compensate 80-km data transmission through standard fiber at 1.55 /spl mu/m.
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