Aleksandr Ramaniuk

Aleksandr Ramaniuk

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 May 2018 in Applied Optics
Verified
Journal Article
Closed access
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QDQuang Ho Dinh
Quang Ho Dinh
Jacek PniewskiJacek Pniewski
Jacek Pniewski
HVHieu Le Van
Hieu Le Van
ARAleksandr Ramaniuk
Aleksandr Ramaniuk
VLVan Cao Long
Van Cao Long
RBRyszard Buczynski
Ryszard Buczynski
A photonic crystal fiber (PCF) made of fused silica glass, infiltrated with carbon tetrachloride (CCl4), is proposed as a new source of supercontinuum (SC) light. Guiding properties in terms of effective refractive index, attenuation, and dispersion of the fundamental mode are studied numerically. As a result, two optimized structures are selected and verified against SC generation in detail. The dispersion characteristic of the first structure has the zero-dispersion wavelength at 1.252 μm, while the dispersion characteristic of the second structure is all-normal and equals −4.37  ps·nm−1·km−1 at 1.55 μm. SC generation was demonstrated for the wavelengths 1.064 μm, 1.35 μm, and 1.55 μm. We prove the possibility of coherent, octave-spanning SC generation with 300 fs pulses with only 0.8 nJ of energy in-coupled into the core with each of the studied structures. Proposed fibers are fully compatible with all-silica fiber systems and PCFs with wide mode area, and can also be used for all-fiber SC sources. The proposed solution may lead to new low-cost all-fiber optical systems.

22 June 2016 in Applied Optics
Verified
Journal Article
Closed access
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Jacek PniewskiJacek Pniewski
Jacek Pniewski
TSTomasz Stefaniuk
Tomasz Stefaniuk
HVHieu Le Van
Hieu Le Van
VLVan Cao Long
Van Cao Long
LVLanh Chu Van
Lanh Chu Van
RBRyszard Buczynski
Ryszard Buczynski
We present a numerical study of the dispersion characteristic modification of nonlinear photonic crystal fibers infiltrated with liquids. A photonic crystal fiber based on the soft glass PBG-08, infiltrated with 17 different organic solvents, is proposed. The glass has a light transmission window in the visible–mid-IR range of 0.4–5 μm and has a higher refractive index than fused silica, which provides high contrast between the fiber structure and the liquids. A fiber with air holes is designed and then developed in the stack-and-draw process. Analyzing SEM images of the real fiber, we calculate numerically the refractive index, effective mode area, and dispersion of the fundamental mode for the case when the air holes are filled with liquids. The influence of the liquids on the fiber properties is discussed. Numerical simulations of supercontinuum generation for the fiber with air holes only and infiltrated with toluene are presented.

1 November 2019 in Optics Communications
Verified
Journal Article
Closed access
ARAleksandr Ramaniuk
Aleksandr Ramaniuk
PJPawel S. Jung
Pawel S. Jung
DCDemetrios N. Christodoulides
Demetrios N. Christodoulides
WKWieslaw Krolikowski
Wieslaw Krolikowski
MTMarek Trippenbach
Marek Trippenbach

1 March 2021 in Optics Express
Verified
Journal Article
Closed access
ARAleksandr Ramaniuk
Aleksandr Ramaniuk
MTMarek Trippenbach
Marek Trippenbach
PJPawel S. Jung
Pawel S. Jung
DCDemetrios N. Christodoulides
Demetrios N. Christodoulides
WKWieslaw Krolikowski
Wieslaw Krolikowski
Gaetano AssantoGaetano Assanto
Gaetano Assanto
We investigate scalar and vector multi-hump spatial solitons resulting from competing Kerr-like nonlinear responses excited in a nonlocal medium by either one or two (mutually incoherent) light beams. Two-color vector supermode solitons are more amenable to control but exhibit an intriguing form of spontaneous symmetry breaking in propagation.

1 June 2018 in Symmetry
Verified
Journal Article
Open access
PDF file
ARAleksandr Ramaniuk
Aleksandr Ramaniuk
NHNguyen Viet Hung
Nguyen Viet Hung
MGMichael Giersig
Michael Giersig
KKKrzysztof Kempa
Krzysztof Kempa
VKVladimir Konotop
Vladimir Konotop
MTMarek Trippenbach
Marek Trippenbach
We present the study of the dynamics of a two-ring waveguide structure with space-dependent coupling, linear gain and nonlinear absorption; the system that can be implemented in polariton condensates, optical waveguides and nanocavities. We show that by turning on and off local coupling between rings, one can selectively generate a permanent vortex in one of the rings. We find that due to the modulation instability, it is also possible to observe several complex nonlinear phenomena, including spontaneous symmetry breaking, stable inhomogeneous states with an interesting structure of currents flowing between rings, the generation of stable symmetric and asymmetric circular flows with various vorticities, etc. The latter can be created in pairs (for relatively narrow coupling length) or as a single vortex in one of the channels, which later alternates between channels.

1 November 2017 in Optics Communications
Verified
Journal Article
Closed access
Jacek PniewskiJacek Pniewski
Jacek Pniewski
ARAleksandr Ramaniuk
Aleksandr Ramaniuk
RKRafał Kasztelanic
Rafał Kasztelanic
Mateusz SmietanaMateusz Smietana
Mateusz Smietana
MTMarek Trippenbach
Marek Trippenbach
RBRyszard Buczyński
Ryszard Buczyński