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Managing group-delay (GD) spread is vital for reducing the complexity of digital signal processing (DSP) in long-haul systems using multi-mode fibers. GD compensation through mode permutation, which involves periodically exchanging power…

Optics · Physics 2025-05-13 Oleksiy Krutko , Rebecca Refaee , Anirudh Vijay , Nika Zahedi , J. M. Kahn

The ability to spatially modulate the electronic properties of solids has led to landmark discoveries in condensed matter physics as well as new electronic applications. Although crystals of strongly correlated metals exhibit a diverse set…

Rotational misalignment of two stacked honeycomb lattices produces a moir\'e pattern that is observable in scanning tunneling microscopy as a small modulation of the apparent surface height. This is known from experiments on highly-oriented…

Graded index microstructured polymer optical fiber incorporating a specially designed air-hole array featuring variable air-hole diameters and inter-hole separation is proposed, fabricated and characterized in view of the fiber potential…

Optics · Physics 2014-09-24 Tian Ma , Andrey Markov , Lili Wang , Maksim Skorobogatiy

We demonstrate a numerical technique that can evaluate the core-to-core variations in propagation constant in multicore fibre. Using a Markov Chain Monte Carlo process, we replicate the interference patterns of light that has coupled…

A detailed investigation of the nonlinear multimodal interference in a short graded-index multimode optical fiber is presented. The analysis is performed for a specific device geometry, where the light is coupled in and out of the multimode…

Optics · Physics 2013-07-17 Elham Nazemosadat , Arash Mafi

We present a framework for the paraxial wave equation based on propagation-dependent unitary transformations closely related to the Lewis-Ermakov invariant. This approach establishes a formal equivalence between free-space propagation and…

Excessive accumulation of group-delay (GD) spread increases computational complexity and affects tracking of receiver-based multi-input multi-output signal processing, posing challenges to long-haul mode-division multiplexing in multimode…

We control the diffusion of light in a disordered photonic waveguide by modulating the waveguide geometry. In a single waveguide of varying cross-section, the diffusion coefficient changes spatially in two dimensions due to localization…

Optics · Physics 2014-07-30 Raktim Sarma , Timofey Golubev , Alexey Yamilov , Hui Cao

We review both theoretical and experimental advances in the recently emerged physics of modulated photonic lattices. Artificial periodic dielectric media, such as photonic crystals and photonic lattices, provide a powerful tool for the…

Previous studies of the modulation instability (MI) of continuous waves (CWs) in a two-core fiber (TCF) did not consider effects caused by co-propagation of the two polarized modes in a TCF that possesses birefringence, such as cross-phase…

Optics · Physics 2012-07-03 J. H. Li , K. S. Chiang , B. A. Malomed , K. W. Chow

We study modulational instability (MI) in optical fibers with random group-velocity dispersion (GVD). We consider Gaussian and dichotomous colored stochastic processes. We resort to different analytical methods (namely, the cumulant…

Modal noise appears due to the non-uniform and unstable distribution of light intensity among the finite number of modes in multimode fibres. It is an important limiting factor in measuring radial velocity precisely by fibre-fed…

Instrumentation and Methods for Astrophysics · Physics 2023-12-29 Supriyo Ghosh , Chantira Boonsri , William Martin , Hugh R. A. Jones , Piyamas Choochalerm , Sarah Usher , Stephanos Yerolatsitis , Thomas Wocial , Thomas Wright

Novel photonic structures such as multi-core fibers and graphene based arrays present unique opportunities to manipulate and control the propagation of light. Here we discuss nonlinear dynamics for structures with a few (2 to 6) elements…

We present theoretical and experimental evidence of high-gain far-detuned nonlinear frequency conversion, extending towards both the visible and the mid-infrared, in a few-mode graded-index silica fiber pumped at 1.064 $\mu$m, and more…

To explore resonance phenomena in the nonlinear region, we show by experimental measurements and theoretical analyses that resonance happens in modulation instability (MI) from non-instantaneous nonlinearities in photorefractive crystals.…

Pattern Formation and Solitons · Physics 2018-08-01 Ray-Ching Hong , Chun-Yan Lin , You-Lin Chuang , Chien-Ming Wu , Yonan Su , Jeng Yi Lee , Chien-Chung Jeng , Ming-Feng Shih , Ray-Kuang Lee

We report an optical fiber experiment in which we study nonlinear stage of modulational instability of a plane wave in the presence of a localized perturbation. Using a recirculating fiber loop as experimental platform, we show that the…

Pattern Formation and Solitons · Physics 2019-02-13 Adrien E. Kraych , Pierre Suret , Gennady El , Stephane Randoux

A linear but global numerical model for the magnetorotational instability (MRI) in disk geometry is considered to estimate the instability parameters for galaxies. Similarity rules suggested by a local analysis are applied to reveal a…

Astrophysics · Physics 2016-08-16 L. L. Kitchatinov , G. Rüdiger

Radiation heat transfer in a graded-index medium often suffers accuracy problems due to the gradual changes in the refractive index. The finite element method, meshfree, and other numerical methods often struggle to maintain accuracy when…

Numerical Analysis · Mathematics 2024-12-25 K. Murari , S. Sundar

Topological magnetic textures are of great interest in various scientific and technological fields. To allow for precise control of nanoscale magnetism, it is of great importance to understand the role of intrinsic defects in the host…

Mesoscale and Nanoscale Physics · Physics 2021-07-22 Marcel Möller , John H. Gaida , Claus Ropers