Practical implementation of digital signal processing for mitigation transmission impairments in optical communication systems requires reduction the complexity underlying algorithms. Here, we investigate application convolutional neural networks compensating nonlinear distortions a 3200 km fiber-optic 11x400-Gb/s WDM PDM-16QAM link with focus on optimization corresponding algorithmic complexity. We propose design that includes original initialisation weights layers by filter predefined...

We report on the thermalization of light carrying orbital angular momentum in multimode optical fibers, induced by nonlinear intermodal interactions. A generalized Rayleigh-Jeans distribution asymptotic mode composition is obtained, based conservation momentum. confirm our predictions numerical simulations and experiments holographic decomposition beams. Our work establishes new constraints for achievement spatial beam self-cleaning, giving previously unforeseen insights into underlying...

We develop a theoretical framework for modeling of continuous wave Yb-doped fiber lasers with highly nonlinear cavity dynamics. The developed approach has shown good agreement between predictions and experimental results particular scheme laser large spectral broadening during single round trip. model is capable to accurately describe main features the experimentally measured outputs such as power efficiency slope, leakage through fibre Bragg gratings, shape generated radiation.

As recently revealed, chirped dissipative solitons (DSs) generated in a long cavity fiber laser are subject to action of stimulated Raman scattering (SRS). Here we present theoretical and experimental study the DS formation evolution presence strong SRS. The results demonstrate that rising noisy pulse (RP) acts not only as an additional channel energy dissipation destroying DS, but on contrary can support it complex bound RP comparable duration. In complex, affords amplification RP, whereas...

We present schemes for geometric phase compensation in an adiabatic passage which can be used the implementation of quantum logic gates with atomic ensembles consisting arbitrary number strongly interacting atoms. Protocols using double sequences stimulated Raman (STIRAP) or rapid (ARP) pulses are analyzed. Switching sign detuning between two STIRAP sequences, inverting ARP pulses, provides state transfer well-defined amplitude and independent atom Rydberg blockade regime. Using these pulse...

Dissipative solitons (also known as auto-solitons) are stable, nonlinear, time-or space-localized solitary waves that occur due to the balance between energy excitation and dissipation.We review theory of dissipative applied fiber laser systems.The discussion context includes classical Ginzburg±Landau Maxwell±Bloch equations their modifications allowing description laser-cavity-produced waves.Practical examples systems generating discussed.

We demonstrate light pulse combining and compression using a continuous-discrete nonlinear system implemented in multi-core fiber (MCF). It is shown that the pulses initially injected into all of cores ring MCF are combined by nonlinearity small number with simultaneous compression. 77% energy one core over 14× 20-core MCF. also suggested scheme insensitive to phase perturbations. Nonlinear spatio-temporal manipulation fibers can be exploited for various applications, including compression,...

Using the cubic Ginzburg-Landau equation as an example, we demonstrate how inverse scattering transform can be applied to characterize coherent structures in dissipative nonlinear systems. this approach one reduce number of effective degrees freedom system when dynamic is dominated by structures, even if they are embedded dispersive waves and unstable behavior.

We propose to exploit a self-focusing effect in the atmosphere assist delivering powerful laser beams from orbit ground. demonstrate through numerical modeling that when length is comparable with height spot size on ground can be reduced well below diffraction limits without beam quality degradation. The density variation suppresses filamentation and provides of as whole. use light greatly relax requirements for orbital optics receivers.

We examine the impact of recovery time a semiconductor saturable absorber together with value its saturation fluence, total net gain, and cavity dispersion on femtosecond pulse generation by mode-locked fiber lasers resulting in massive optimization system performance. Stable regimes asymptotic single-pulse have been identified as zones parameter map. demonstrate that stable regime leads to formation pulses chirp, width, peak power strongly varying during one round trip while slowly...

We present direct real-time experimental measurements and numerical modeling of temporal statistical properties for the Ytterbium-doped fiber laser with spectral bandwidth ~2 GHz. The obtained results demonstrate nearly exponential probability density function intensity fluctuations. A significant decrease below Gaussian has been experimentally observed fluctuations having value more than 2.5 average that may be treated as indication some mode correlations.

We highlight two important aspects related to a mathematical modeling of pulsed fiber lasers with long and ultra-long ring cavity -impact an initial noise length on generation single optical pulses. Using as example simple scalar model laser that describes the radiation build-up from following intra-cavity pulse dynamics during round trip we study dependence generated characteristics resonator in range 30 m up 2 km.

We analyze spatiotemporal solitons in multimode optical fibers and demonstrate the existence of stable solitons, a sharp contrast to earlier predictions collapse multidimensional three-dimensional media. discuss coexistence blow-up solutions stabilization by low-dimensional external potential graded-index media, also predict higher-order nonlinear waves such as dipole-mode solitons. To support main conclusions our numerical studies we employ variational approach derive analytically stability...

We propose a modification of the conventional perturbation-based approach fiber nonlinearity compensation that enables straight-forward implementation at receiver and meets feasible complexity requirements. have developed model based on perturbation analysis an inverse Manakov problem, where we use received signal as initial condition solve equations in reversed direction, effectively implementing perturbative digital backward propagation enhanced by machine learning techniques. To determine...

Energy of chirped dissipative solitons (DS) generated in fiber lasers may exceed a threshold stimulated Raman scattering (SRS) leading to formation noisy pulse (RP). As we demonstrated recently, feedback loop providing re-injection the into laser cavity can form soliton (RDS) with similar characteristics those main soliton. Here, present results optimization RDS spectra. First experimental coherent combining DS and are also shown.

Long-lived light bullets fully localized in both space and time can be generated novel photonic media such as multicore optical fiber or waveguide arrays. In this paper we present detailed theoretical analysis on the existence stability of discrete-continuous using a very generic model that occurs number applications.

Nowadays, improving the accuracy of computational methods to solve initial value problem Zakharov-Shabat system remains an urgent in optics. In particular, increasing approximation order is important, especially problems where it necessary analyze structure complex waveforms. this work, we propose two finite-difference algorithms fourth time variable. Both schemes have exponential form and conserve quadratic invariant system. The second scheme allows applying fast with low complexity (fast...

Abstract Purpose Inadvertent and/or unknowing exposure to drugs and drug residues has been frequently debated in situations of so-called adverse analytical finding (AAF) the context sports testing programs. Transfer via unprotected intercourse is a conceivable scenario but scientific data authentic case reports are scarce. Herein, investigations into two AAFs with peroxisome proliferator-activated receptor delta (PPARδ) agonist GW1516 reported discussed. Methods To probe for contamination...