The tailoring of the group velocity dispersion (GVD) of an optical fiber is critical in many applications, influence on the bandwidth of information transmission in optical communication systems, successful utilization of nonlinear optical properties in applications such as supercontinuum generation, wavelength conversion and harmonic generation via stimulated Raman scattering ...In this work, we propose a design of ultra-flattened photonic crystal fiber by changing the diameter of the air holes of the cladding rings. The geometry is composed of only four rings, hexagonal structure of air holes and silica as background of the solid core. As a result, we present structures with broadband flat normal dispersion on many wavelengths bands useful for several applications. We obtain flat normal dispersion over 1000 nm broadband flat normal dispersion below -7 [ps/nm.km], and ultra-flat near zero normal dispersion below -0.2 [ps/nm.km] over 150 nm. The modeled photonic crystal fiber would be valuable for the fabrication of ultra-flattened-dispersion fibers, and have potential applications in wide-band high-speed optical communication systems, supercontinuum generation and many other applications.
In this work, we design a highly nonlinear noncircular core photonic crystal fiber (HNL-PCF) for the generation of a supercontinuum (SC) at 1.3 μm having minimum anomalous dispersion and using many nonlinear effects by introducing self-phase modulation (SPM), self-steepening and Raman effects. The proposed geometry of the HNL-PCF is composed of six rings of air-holes and silica as a background material for the core. Using the vectorial Finite Element method (FEM) with a perfectly matched layer (PML), the proposed HNL-PCF is numerically modeled for determining its characteristics as Group Velocity Dispersion (GVD) and nonlinear properties. After optimizing the properties of the proposed HNL-PCF (GVD= - 0.95 ps2/km; γ= 55.45 [W.km]-1 around 1.3 μm), the SC is generated by solving the nonlinear Schrodinger equation (NLSE), that contains different parameters of the cited nonlinear effects, with split-step Fourier method (SSFM). The introducing of this different effects in our work allows to generate a SC of spectral bandwidth SBW=260 nm at 1,3 μm using only 1.89 mm long of PCF.
In this work, our main achievement was to improve the sensitivity of a biosensor - evanescent mode type; hence contributing to the design of a bacteria sensor in water by choosing an appropriate microstructure of Photonic crystal fiber (PCF) and polymer materials.
We investigate analytically and numerically the eﬀect of the higher order dispersion on the dynamic of a photonic crystal fiber resonator pumped continuously by a coherent injected beam. The linear stability analysis shows that the fourth order dispersion bounds the zone of modulation instability between two pump power levels and predict a motion of solution induced by the broken symmetry mediated by the third order dispersion. We perform a weakly non linear analysis on the vicinity of the first threshold associated with modulation instability. The amplitude and the non linear correction of velocity of periodic structures are estimated. This analysis allowed us to determine the threshold of apparition of bright localized structures and we have also shown that dark localized structures can be stabilized on the neighborhood of the second threshold of modulation instability. Numerical solutions of the governing equations are in close agreement with analytical predictions.
We are arrived in this work to apply the SC-FEM to PCF to determine the modal field distribution and other
important characteristics as normalized frequency, numeric aperture and chromatic dispersion according to the
optogeometric parameters of the fiber. We could vanish the chromatic dispersion in the PCF at many low
wavelengths because of its large degree of liberty.
The objective of our work is to present a tool for study of the light propagation in the new generation optical fibers that is
the modal approach, this last is based on hypotheses that facilitate the calculation of the solutions of the dispersion
equations and the coupling coefficients between different modes propagating in the fiber. This study allow us to
characterize the propagation in several types of fibers: standards fibers, photonic crystal fibers, and fiber Gratting.
The transmission high-speed links requires the control of the phenomenon of polarization mode dispersion because it
can limit the bandwidth of the transmitted signal mainly for long distances. This article presents two used methods of
modeling in order to calculate the PMD in the single mode optical fiber links and evaluate its influence on the
propagated signal. The results obtained in the modeling have been compared with experimental results in order to
validate the proposed methods of modeling.