Journal of Nonlinear Optical Physics & Materials

This paper studies polarized cubic–quartic solitons that are modeled by Fokas–Lenells equation in birefringent fibers. Two integration schemes recovered a spectrum of soliton solutions to the model. Subsequently, the bright solitons compute the corresponding conserved quantities from the respective densities that are recovered by the multiplier approach.

In this paper, we present a novel erbium–ytterbium doped fiber amplifier (EYDFA) + Raman + EYDFA hybrid optical amplifier (HOA) for a super-dense wavelength division multiplexing (SD-WDM) system application. The performance of the 100-channel system has been investigated for an overall data rate and channel spacing of 100Gb/s and 0.4nm, respectively, over a wavelength span of 1550–1589.9nm. HOA has been optimized for Raman length, EYDFA lengths, pump powers and Er${}^{+}$ concentrations to achieve high average gain and low gain variation ratio of 40.41dB and 0.40respectively. The optimized configuration of the proposed HOA has been compared with EYDFA + Raman and Raman + EYDFA HOA configurations. The achieved high and flat gain with an acceptable output optical signal to noise ratio (OSNR) in case of EYDFA + Raman + EYDFA HOA; makes it an optimum choice for SD-WDM systems.

This work recovers cubic–quartic soliton solutions to the Lakshmanan–Porsezian–Daniel model by the method of undetermined coefficients. Both polarization-preserving fibers and birefringent fibers are studied. The conservation laws for polarization-preserving fibers are also retrieved and enumerated. The existence criteria for the displayed solitons are also presented.

Single crystals of pure and 2mol.% adipic acid (hexanedioic acid) -doped ammonium dihydrogen phosphate (ADP) were grown by conventional slow evaporation of aqueous solution technique. The powder X-ray diffraction and FT-IR analyses indicate that the crystals undergo considerable stress as a result of doping. UV–Vis studies show that the absorption of the adipic acid-doped crystals is less than that of pure ADP. Thermal studies (TG/DTG) disclose that the decomposition temperature of doped ADP is more than that of pure ADP. Vicker’s microhardness study reveals that the addition of adipic acid increases the hardness of the ADP. SHG efficiency and piezoelectric charge coefficient of adipic acid-doped ADP are higher than that of pure ADP.

We study the modulation instability (MI) for optical wave propagation in the presence of slowly varying saturable nonlinearity, group velocity dispersion and a PT-symmetric external potential over the length of tapered graded-index waveguide. First we study the MI with space-dependent dispersion and saturated nonlinearity and then with constant dispersion and saturated nonlinearity. We analytically compute the growth rate and analyze the possibility of existence of MI for focussing and defocussing nonlinearities for different choices of group velocity dispersion terms and saturated nonlinearities. We observe that MI is independent of PT symmetric potential term and typically depends upon the choice of group velocity dispersion term, nonlinearity, saturated nonlinearity and wave amplitude. MI gain decreases with increase in cw amplitude however it increases with increase in saturated nonlinearity both for focussing and defocussing nonlinearities.

A theoretical formulation followed by numerical analysis describing Brillouin amplification in compound (A^IIIB^V and A^IIB^VI) semiconductors is explored. The threshold condition for the onset of Brillouin amplification is determined. Well above the threshold intensity, the influence of piezoelectricity, doping concentration, and external magnetostatic field on the parameters characterizing Brillouin amplification viz. Brillouin amplification coefficient, transmitted intensity of Brillouin-scattered Stokes mode (BSSM), and Brillouin cell efficiency of the Brillouin cell isestimated. Numerical analysis is made for three different Brillouin cells consisting of $n$-InSb, $n$-GaAs, and $n$-CdS, at 77K duly irradiated by a pulsed CO₂ laser. Efforts are directed towards to determine appropriate values of doping concentration and magnetostatic field to enhance the parameters characterizing Brillouin amplification, at lower excitation intensity, and to establish the suitability of compound semiconductors as hosts for fabrication of efficient Brillouin amplifiers.