Valeriy Kh. Bagmanov

Adaptive SLM-based compensation of intermodal interference in few-mode optical fibers

Transmission of optical beams with phase front vorticity through relevant distances in optical fibers poses a problem of time-dependent intermodal interference with random complex coefficients. In this paper we propose a method for compensation of interference between LP-modes, propagating through the optical fiber. To implement optical-domain modal filtering, reconfigurable diffractive optical element matched with particular modes is considered. Such an element may be encoded as phase-only hologram by means of SLM. With this approach modes can be separated spatially in the compensating diffractive element far field and handled independently with corresponding complex coefficients. Efficiency of the proposed method is confirmed by computer simulation results.

Information technology of remotely sensed optical image analysis on the basis of multiscale conceptions integration

The information technology of remotely sensed image analysis is based on system integration of two main concepts: diffractive optical elements (DOEs) aided multispectral preprocessing and multiscale analysis. Proposed technology allows to: decrease the threshold of hidden signal detection; detect the signals with unknown form; improve the performance of subpixel signal detection and estimation in case of limited resolution of sensors. Data preprocessing method for anomaly detection on the base of DOE technology is developed. DOE-based technology is implemented and tested. Nonparametric statistic methods for signal detection and estimation are proposed. Multiresolution image analysis methods are applied for anomaly detection and estimation.

Justification and analysis of OAM-carrying electromagnetic fields spinor propagation equation for dispersive media

In this paper we introduce a novel approach for analysis of the information transmission process in mode-divisionmultiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwell’s equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the welldeveloped quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission. Spinor propagation equation of EM fields carrying angular orbital momentum in dispersive media is also given.

Nonlinear impairments in mode division multiplexed systems

In this paper we consider nonlinear impairments of mode division multiplexed signals with QAM modulation in optical fibers with linear mode coupling of spatial modes. We simulate simultaneous propagation of fundamental mode and two first-order vortex modes in standard single mode fiber at 850 nm and propagation of fundamental mode and first- and second-order vortices in step-index fiber with enlarged core at 1550 nm. Simulation results shows that in strong coupling regime linear coupling lead to sufficient increasing of nonlinear impairments, but QAM-modulated signal is more robust to this effect than OOK modulated signal.

Spinor-based approach on wave processes in optical fiber

In this paper we introduce a novel approach for analysis of the information transmission process in mode-divisionmultiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwell’s equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the well-developed quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission.

Increase of nonlinear signal distortions due to linear mode coupling in space division multiplexed systems

This paper is focused on the analysis of linear and nonlinear mode coupling in space division multiplexed (SDM) optical communications over step-index fiber in few-mode regime. Linear mode coupling is caused by the fiber imperfections, while the nonlinear coupling is caused by the Kerr-nonlinearities. Therefore, we use the system of generalized coupled nonlinear Schrödinger equations (GCNLSE) to describe the signal propagation. We analytically show that the presence of linear mode coupling may cause increasing of the nonlinear signal distortions. For the detailed study we solve GCNLSE numerically for the standard step index fiber at the wavelength of 850 nm in the basis of spatial modes with helical phase front (vortex modes) and for a special kind of few-mode fiber with enlarged core, providing propagation of five spatial modes at 1550 nm. Simulation results confirm that the linear mode coupling may lead to a significant increase of the nonlinear distortions. It is necessary to take this phenomenon into account in SDM systems with linear compensation of mode coupling, because the nonlinear distortions may sufficiently decrease the effectiveness of the compensation.

Fiber optics systems mode analysis based on Dirac equation

In this paper we introduce a novel approach for analysis of the information transmission process in mode-division-multiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwell’s equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the well-developed quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission.

Derivation of the mode division multiplexed information transmission principles based on the spinor representation of Maxwell's equations

In this paper we introduce a novel approach for analysis of the information transmission process in mode-division-multiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwells equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the well-developed quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission.

WDM signal impairments due to the cross-modulation in the case of nonlinear transmission in the presence of PMD

This paper presents results of investigation on cross-phase modulation effect and influence of polarization effects on it. It is shown that fast polarization scrambling can effectively reduce impairments caused by cross-phase modulation in the case of NRZ signal.

Recurrent synthesis of multilayer dielectric selective mirror

This article presents a solution to the problem of synthesis of multilayer dielectric mirrors for the selective ROADM.