This PDF file contains the front matter associated with SPIE Proceedings Volume 11793, including the Title Page, Copyright information, and Table of Contents.

This paper describes virtualization in optical networks. The rapid growth of Internet traffic, new services and the rapid development of technologies such as the Internet of Things and next generation 5G mobile networks require greater demands on the bandwidth of optical networks. Variety of network services requires network transport with more flexible bandwidth access capabilities. This means that future transport networks must provide flexible bandwidth for dynamic services through intelligent management. In the same time, optical networks still face certain challenges in introducing and expanding services. The main difficulty is to provide guaranteed performance, including access to routing, convergence and route computation times, path detection time, reliability and resource utilization rate. Current level of operation and maintenance of optical networks does not meet the requirements of customers. For these reasons, optical virtualization is a necessary technology to meet the specified set of network requirements, while providing the necessary isolation between its segments. This document first introduces the concept of optical network virtualization and its application for optical network elements and transport technologies. Then the paper describes the various technologies of virtualization in optical networks and the existing problems.

Method for obtaining a 3D image using a CCD sensor is proposed. A prototype that implements the proposed method is developed. Received and processed data using a prototype. Using the prototype, experimental data on the distance to the test objects were obtained. Based on the data obtained, a depth map was built. The accuracy of the built depth map is 5 сm.

To achieve a dense and efficient deployment of RRH microcells and easy initialization of their central wavelengths, tunable colorless laser transmitters are included in the ONU of the transport domain of 5G mobile radio access networks, making it easy to tune and control the radiation wavelength using various mechanisms. In the ONU, upstream wavelength control is necessary due to possible errors in setting the center wavelength during initial connection with OLT (BBU), as well as due to wavelength drift due to aging of the laser transmitter. The paper presents a new method of straight (ONU-OLT) dual-frequency wavelength initialization in one of the WDM-PON channels, built on AWG, using the process of determining the maximum amplitude modulation coefficient of the probe radiation components beating envelope as a parameter that indicates tuning to its central wavelength. Using the method makes it possible to increase the signal-to-noise ratio of the initialization channel, its sensitivity, and the accuracy of tuning to the center of the AWG channel in comparison with the known methods using the processes of direct detection of single-frequency probe radiation.

Tuning the wavelength of a colorless laser transmitter, used to build an upstream channel in the WDM-PON transport domain of a 5G mobile radio access network, to the wavelength of the maximum transmission of its multiplexer channel is implemented by a number of regulated and proactive procedures. Part I is a beginning of this article and is devoted to straight initialization. The main attention in the article will be paid to the consideration of reflective type systems. Broadband and single-frequency reflective methods for tuning direct modulation lasers: VSCEL, DFB, DBR, and external modulation lasers: integral module on InP-substrate, with direct detection and heterodyne reception are analyzed, their advantages and disadvantages are determined. The transition to modulation reflectometric methods of tuning on few close frequencies is substantiated, for which two- and three- frequency technologies for multiplexer probing based on EML lasers with scanning are proposed. The use of methods makes it possible to increase the signal-to-noise ratio, sensitivity and accuracy of multiplexer spectral characteristics measurements, and, consequently, the accuracy of tuning the wavelength of a colorless laser transmitter to the central wavelength of one of multiplexer channels.

The article presents a comparative analysis of the reliability characteristics of fiber-optic communication lines in the application of underground laying of optical cable, mini-trench installation technique and cable in the outer protective duct. It is shown that the availability factor of underground laying armored optical is less than that of cables laid in the, outer protective duct and in microduct in the mini-trench.

Diffractive optical elements for the formation of laser beams with intensity distributions in the form of ring light traps with zero total orbital angular momentum are considered and studied by means of a computational experiment. The beams are formed as a superposition of two vortex beams with the same magnitude but different sign orbital angular momentum by encoding multilevel diffractive optical elements (256 quantization levels) in polar angle. The considered elements form an intensity distribution in the form of spots located in the same places where the light rings are located in the initial vortex beams. Such beams can possess all the properties of vortex beams when propagating in the atmosphere, for example, increased stability to aerosol noise.

In this paper, we present the performance analysis of the uplink channel based on the Radio-over-Fiber technology for fullduplex radio access networks. The uplink channel test bench utilizes the and layout, as well as the course of the experiment are shown. The results of monitoring the power of the signal when it passes through the segment of the Radio-over-Fiber network are presented. In the final section, we calculate the signal power at the radio remote unit for any commercial broadband access network and compare it with the bench measurements. As a result, the calculated signal level was almost 20 dB lower than the measured signal at the output of the uplink channel test setup.

The paper studies the problem of complex safety in personal area network and local area network in the Internet of Things project's boundaries. The electromagnetic safety analysis of various wired, wireless and fiber-optics technologies have realized by statistical simulation with applying the spatial analogue of the Huygens- Kirchhoff principle. The model of equivalent radiator for estimation of Internet of Things objects safety is offered. The simulation results of the statistical model in the form of histograms of the field strengths levels of the electric E-field and magnetic H-field, their phase and polarization characteristics must be interpreted and adapted in relation to the problems of specific engineering. Recommendations for the selection of personal area network and local area network elements are given.

In this paper the chiral fiber Bragg gratings (ChFBG) for generation of fiber modes carrying orbital angular momentum (OAM, vortex modes) are considered. Within the framework of the article, a generalized mathematical model of ChFBG is presented including an arbitrary function of apodization and chirping, which makes it possible to calculate gratings that form vortex modes of a given order for the required frequency range with the required reflection coefficient. In addition, a matrix method based on the mathematical apparatus of the coupled modes theory for describing ChFBG is proposed, simulation of the considered fiber structures is carried out.

In this paper, we investigate a wavefront sensor based on the optical expansion of the analyzed field in the basis of Zernike functions using a multichannel diffractive optical element. Correlation peaks at the centers of diffraction orders correspond to the detection of specific aberrations in the analyzed field, and the peak intensity corresponds to the magnitude of the aberration. The analysis of the threshold sensitivity of the considered wavefront aberration sensor is carried out. In a number of numerical experiments, the threshold value of the sensitivity of the sensor under consideration was obtained. It turned out that when analyzing wavefront aberrations, spurious aberrations can be detected when the wavefront deviation exceeds a certain threshold value, and this value varies for each type of aberration.

In this work, we proposed a compact design of a tunable high-pass filter based on the one-dimensional photonic crystal waveguide. The device design is simple and cut-off wavelength can be tuned by a few geometric parameters. The spectral characteristics of the high-pass filter are calculated for the wavelength range of 1200 nm to 2000 nm. The numerical simulations suggest that the extinction ratio of >22 dB is obtained for the wavelength range lying in the photonic bandgap for the device footprint of 3.4 x 1 μm². We believe that our findings are useful for the realization of photonic integrated circuit filters with miniaturized footprint.

We studied the autofocusing properties of chirp beams whose phase has an arbitrary power-law dependence on the radius. Two types of such beams were considered (theoretically and numerically): two-parameter beams corresponding to a generalized lens, and three-parameter beams corresponding to a displaced generalized lens. On the basis of theoretical analysis, the conditions imposed on the parameters of the beams, under which the off-axis caustic is formed, are revealed and the equation of the caustic line is obtained. It is shown how changing the beam parameters affects the autofocusing properties. The results of numerical simulation are consistent with theoretical calculations. Thus, we can form beams with controlled autofocusing properties, which are in demand in various applications of optics and photonics.

A multidimensional signal superposition is an important task in the television system. Such processing is applied for decreasing information storage improving the quality of television images and for solving intelligence tasks such as recognition and tracking by interest objects. The algorithm about homography parameters estimation for superposition multidimensional signals was shown in the current article. The algorithm includes several stages of processing. They are reference point recognition, automatic matching between datasets, calculation of the homography parameters. The matching between datasets bases on a method for compare images of the log-polar coordinate system. This method is invariant of the scale and rotation. Also, the research shows that the probability of points matching is characterized high value of the wrong decision if only one wrong reference point is used for analysis. To fix these disadvantages the decision method was developed. It bases by analyze the several reference algorithm that is approbation by real images. The superposition of multidimensional television signals is a pleasing solution by developing approaches.

The paper proposes a video surveillance scheme for compact placement of a system for railway rolling stock accounting. This design is based on the use of a tilted diffractive optical element and a tilted lens. Such an optical design makes it possible to significantly increase the depth of focus of the imaging system. This work considers the influence of the tilt of a diffractive lens on the shape and size of the focused area. Analytical relations describing the geometry of the focused region for various spectral channels are given. The possibility of increasing by several times the size of the zone of accurate image classification using a neural network has been demonstrated. The proposed approach has been tested on real-world dataset of images of house number plates.

The development of piezoelectric and optical elements from microcells was carried out and models were prepared for printing on a 3D printer. These designs can be practically used as piezoacoustic or piezoelectric sensors, if added to the composition of the piezoelectric powder, for example, in ultrasonic flow meters, or used to create optical structures, for example, diffractive optical elements. Elements obtained by 3D printing will have properties that differ from the properties of elements obtained by standard methods.

The method for numerical simulation of measuring the concentration of particles of two types in a liquid-based on Rayleigh scattering during their deposition is proposed. The mathematical model takes into account the forces of gravity, hydrostatic lifting force, forces of resistance to motion. Additionally, the contribution of the influence of Brownian liquid motion on the movement of suspended particles was taken into account. The magnitude of the scattering of the light flux as it passes through the volume of liquid with particles suspended in it is modeled. A numerical calculation was carried out according to the developed mathematical model.

In this paper, we study the propagation of sets of autofocusing laser beams using the fractional Fourier transform. Were considered sets of limited Airy-Gaussian beams, which are shifted from the center. Each of the beams can have additional spatial carrier frequencies that change the nature of beam propagation and their autofocus properties. Using numerical modeling we have shown possibility of controlling the trajectory of the curve during autofocus, and the generating of several autofocuses on the optical axis.

In this paper, comparative modeling of optical vortices focusing by phase and amplitude zone plates is presented. The FullWAVE software package based on finite difference time domain method was used for numerical simulation. The linearly polarized Gaussian vortex beams with wavelength of 532 nm, waist of 8 μm, and topological charge 1, 2 and 3 were proposed as incident light. It is shown that the material of zone plate can significantly influence on focusing process. However, than the higher the topological charge of incident beam the more similar formed by phase and amplitude zone plats at the focus fields are.

Here, we derive theoretically the topological charge (TC) of several vortex laser beams without the circular symmetry, namely asymmetric Laguerre-Gaussian (LG), asymmetric Bessel-Gaussian (BG), and asymmetric Kummer beams. Although such beams are obtained as superposition of respective conventional LG, BG, and Kummer beams, these beams have the same TC equal to that of a single mode, n. The induced asymmetry affects the normalized orbital angular momentum (OAM) of all these beams, and what is more, it affects the OAM of different beams differently. However, whatever the asymmetry degree, TC of the beams remains unchanged and equals n. Theoretical findings are validated via numerical simulation.

The problem with existing flow meters is a relatively high measurement error, which is associated with a lack of information on the flow profile. In order to create a reference device that makes it possible to study the flow profile due to a larger number of sensors, with bore size 50 mm primary transducer with fourteen channels is developing and manufacturing. This device can provide more accurate results due to the use of multiple channels of ultrasonic signal passage, which makes it possible to calculate large time points along the entire section of the pipe, as well as the ability to visualize the flow profile. In the course of the work, a 3D model of the primary transducer was developed in accordance with the requirements and conditions for the passage of ultrasound through a liquid medium, when it was necessary to take into account the simultaneous operation of several channels at once, taking into account the fact that the paths of ultrasound passage should not intersect. Processing several signals at once becomes possible, since five TDC microcontrollers will be used for all channels.

In this article the principle of instrumental (experimental) determination of the parameters of mode compositions of an optical signal propagating along an optical fiber is described. The measurement scheme is based on the use of a wellknown experimental setup designed to obtain the profile of the refractive index of an optical fiber. In addition to that setup, it is proposed to perform measurements for different angular positions of the investigated optical fiber, and for its different longitudinal positions. The proposed method is realizable in the case when the signal propagating through the optical fiber is characterized by increased intensity, which makes it possible to measure a nonlinear (Kerr) caused addition to the refractive index. It is proposed to calculate the desired mode weight coefficients by the method of probabilistic selection according to the developed method.

The work considered possible models and algorithms based on the analysis of the features of the energy and temporal characteristics and/or characteristics of the directional patterns, taking into account the peculiarities of the spatial location of the source (or sources) of the signal for the subsequent localization of the sound source, in relation to fiber-optic sensor networks, to solve the problem determining with a given accuracy the location of the intruder at the protected facility. As the most optimal, a model based on estimates of the difference in the delay time of acoustic signals at different points of reference of the backscattering characteristic of an optical fiber of a distributed acoustic sensor - DAS was chosen. As an example, the results of calculating the estimates of the error in determining the coordinates of a sound source depending on the noise level in a room with two optical fibers laid parallel along opposite walls are presented.

By simulating sharp focusing of vector beams with azimuthal polarization of fractional order 0 < m <1 (m = 1 is azimuthal polarization, m = 0 is linear polarization), it was shown that the shape of the intensity distribution in the focal spot changes from annular (m = 1) to round (m = 0.5) and then to elliptical ring (m = 0). The opposite changes we can see for the shape of the distribution of the longitudinal component of the Poynting vector (energy flux) in the focal spot: from annular (m = 1) to elliptical (m = 0.5) and then to circular ring (m = 0). The diameter of the focal spot at full width at half maximum for a beam with azimuthal polarization (m = 1) with an optical vortex of the first order for a numerical aperture NA = 0.95 is 0.46 of the wavelength, and the diameter of the axial energy flux for linearly polarized light (m = 0) is 0.45 of the wavelength. Because of this, the answers to the questions: Whether the focal spot is round or elliptical and whether the focal spot is minimal: with azimuthal polarization with a vortex or with linear polarization without a vortex, depend on whether we are considering the intensity at the focus or the energy flow.

In the presented article, the possibilities of calculating the parameters of the modes of optical fibers with depressed claddings by the Gauss approximation method are considered. Calculations are performed for samples of single-mode and few-mode optical fibers with depressed cladding. The calculation results are compared with the technical data of the samples under consideration.

This paper is presented the simple analytical formula for calculating the nonlinear coupling coefficient between modes with arbitrary radial and azimuthal orders for multimode optical fiber. The solution is obtained by a well-known method of Gauss approximation. For example, the present work shows the spectral dependencies of nonlinear coupling coefficients for some low-order modes of optical fibers with step and parabolic refractive index profile.

This work deals with a hot topic of using quantum approaches in advanced telecommunications. Here, the major trend involves exploiting a flow of individual photons for signal transmission, because the photon is impossible to split, measure, copy, or imperceptibly delete. Such manipulations destroy the photon, prohibiting it to reach the recipient. Before the field quantization can be implemented, a problem of the electromagnetic field propagation needs first to be solved within classical electrodynamics, with dynamic quantities then replaced by the corresponding operators. This work describes a procedure for the electromagnetic field quantization in a waveguide with superconducting walls. In an optical fiber with inhomogeneous refractive index, the modes are shown to be non-orthogonal, so that the field can only approximately be quantized using the basis of waveguide modes. Expressions for operators of the electric and magnetic fields are derived, which may prove helpful for calculating both dynamic and other characteristics of the electromagnetic field, including nonclassical states of the electromagnetic field.

The paper presents the concept of liquid media level control systems based on the use of fiber-optic technologies, in particular, addressable fiber Bragg structures. The paper presents methods for the formation of address structures and the principles of retrieving and processing information. The use of addressable fiber Bragg structures makes it possible to abandon the elements of bulk optics in the interrogation scheme, which increases the operational reliability, and simplifies the identification of the sensor in their common array in the measuring system.

Using electronic beam lithography and ion etching we manufactured a metalens with diameter 30 μm, focal length 633 nm and relief depth of 130 nm. The metalens consists from 16 sector subwavelength binary gratings with period 220 nm. The proposed metalens generates a left-hand circularly polarized optical vortex with topological charge 2 when it is illuminated by left-hand circularly polarized light; however, it generates a cylindrical vector beam of the second order when it is illuminated by linearly polarized light. In both cases a region of inverse energy flow occurs in the focal spot.

The paper discusses a method for measuring the profile of the refractive index of an optical fiber and presents the results of a computational experiment that confirm the efficiency of the developed technique.

This work is concerned with some aspects of selection of graded refractive index profiles for couple combination of optical crypto-fibers “encryptor”–“decryptor”. We present some results of experimental approbation of method for differential mode delay (DMD) management by selection and recombination of two corresponding refractive index profiles, differing by technological defects in the core center. Here it is supposed, that combined fiber optic link, containing the sequence of two graded-index multimode optical fibers with strong DMD, occurring due to great technological defect of refractive index profile in the core center with a peak (or dip) in the first and, on the contrary, with a dip (or peak) in the second, provide inverting DMD diagram of selected mode components in the second optical fiber in relation to the first. Therefore, according to earlier on proposed alternative method for implementation of secure data transmission channel protected over physical layer for the "first/last mile" segment of intra-corporate network, the first optical fiber with strong unique distortions is considered as “encryptor”, while the second with inverted DMD diagram implements function of “decryptor” in the optical interface.

The article considers an algorithm for statistical blind deconvolution of images distorted in a random environment and registered as a set of random implementations. The proposed approach reduces the problem of statistical blind image deconvolution to the problem of blind identification of one-dimensional signals. Further, the technique of second-order polynomial statistics generated by random polynomials is used to solve the one-dimensional problem. The article presents the results of modeling the proposed algorithm.

The investigation of the change in the size of the focal spot when laser radiation with radial and circular polarizations passes through a diffractive axicon and an optical element matched to the circular Airy distribution is carried out. The height of the optical elements was varied from 0.5λ to 1.5λ. Near-field diffraction modeling is numerically investigated by the finite difference time domain method. The formation of a thin light tip was shown for both of the considered elements, including for the longitudinal component of the electric field with a laser beam width up to FWHM = 0.36λ.

The article describes an important task for restore object shape, which is measured by triangulation optical sensor. The restored object shape (object contour) makes by spatio-temporal multidimensional signal processing. The data of object contour is received at close moments in time. The core of spatio-temporal multidimensional signal processing bases on the hypothesis that object shape changes slightly at close moments in time. The right restore object shape is provided by the superposition of contour. The superposition algorithm is based on the iteration procedure. The processing contours have matched closer to each other with each new iteration. The first contour is the etalon multidimensional signal. The second contour is a measured signal at close moments in time. Superposition makes by feature points. The feature point of the etalon signal is the contour point, the feature point of the measured signal is the intersection of a normal line (it is calculated by etalon signal) and measured contour. The computer simulation and verification test show improvement result measurement by the developed algorithm.

The estimation of the offset, angle rotation, and other deformation of multidimensional optical video signals is an important task at intelligence video systems. One of the main tasks for estimation of the multidimensional signal deformation is increasing the speed of data processing. The television signals characterized a significant volume of data. This property is a constraint for applying brute force methods. Those methods are the universal solution for estimating unknown parameters of the parametric model. This research describes the issue of measurement offset, rotation, and scale with additive and multiplicative noise for spatial-temporal superposition of television images. The reduction of time processing is provided by the iteration procedure of unknown parameters estimation. This procedure consists of approximation by separate estimate offsets, scale, and rotates.

In this work, training and recognition of the types of aberrations corresponding to individual Zernike functions have been carried out by the pattern of the intensity of the point scattering function (PSF) using convolutional neural networks. The PSF intensity patterns in the focal plane were modeled using the Fast Fourier Transform algorithm. When training a neural network, the learning coefficient and the number of epochs for a dataset of a given size were selected empirically. The average prediction errors of the neural network for each type of aberration were obtained for a set of 15 Zernike functions from a dataset of 15 thousand PSF pictures. As a result of training, for most types of aberrations, averaged absolute errors were obtained in the range 0.012–0.015, however, the determination of the aberration coefficient (magnitude) requires additional research and data, for example, calculating the PSF in the extrafocal plane.

The safety of laser coagulation in the treatment of diabetic retinopathy depends on the correct selection of laser exposure parameters. In this paper, it was proposed to use technology for numerical modeling of the temperature distribution in the fundus based on its structure formed from optical coherence tomography (OCT) images. For such a formation, it is required to process each image and then interpolate the three-dimensional surfaces. Further, the formed structure is used for numerical simulation. This approach will potentially allow automating the extremely time-consuming procedure for choosing a coagulate placement plan. The paper considers algorithms that improve performance when solving the problem of mathematical modeling using the maximum load of CPU and GPU devices, i.e. parallel and high-performance algorithms.

In this paper, an image analysis method for future compression based on a weight model was proposed, which allows one to estimate the significance of the detailing coefficients of the orthogonal multiple-scale wavelet transform in terms of their contribution to the total image energy. The method presupposes the decomposition of the original image into a given number of levels, construction of significance maps for the detailing coefficients of each level before coding of the significant coefficients.

In this paper, an image compression method based on a weight model was proposed, which allows one to estimate the significance of the detailing coefficients of the orthogonal multiple-scale wavelet transform in terms of their contribution to the total image energy. The method presupposes the decomposition of the original image into a given number of levels, construction of significance maps for the detailing coefficients of each level, and coding of the significant coefficients. The software implementation of the proposed method in a high-level language is described, which made it possible to reduce the volume of standard test halftone images by at least six times.

The paper presents a new algorithm for solving the nonlinear Schrödinger equation by the split-step method, which describes the propagation of a high-power ultrashort pulse in an optical fiber. The simulation results of the evolution of a powerful ultrashort pulse during propagation in a single-mode step-index optical fiber, obtained using this algorithm, are presented.

Medical applications are among the tasks of optical technology. The processing of two-dimensional optical signals and images is an urgent task today. One of the most dangerous eye diseases is diabetic macular retinopathy. The first stage in the laser coagulation operation is the stage of fundus image segmentation. The calculation of texture features for solving this problem takes a lot of time. In this paper, we consider the use of a high-performance algorithm for calculating texture features based on distributed computing to speed up the processing and analysis of medical images. Various use cases of the high-performance algorithm on a single node were investigated and compared with sequential and parallel algorithms. The high-performance algorithm achieves a 40x speedup and more under some parameters. Using a highperformance algorithm, analysis and segmentation is performed in less than 1 minute for standard images. The use of a high-performance algorithm for the analysis and segmentation of fundus images avoids the need for a sequential skip-step algorithm, which, due to interpolation, reduces the execution time, but at the same time, accuracy is lost.

A high-precision symmetric optical vector analyzer (OVA) based on amplitude-phase double sideband (DSB) modulation with suppression of an optical carrier is proposed and numerically simulated. Accurate and stable frequency characteristics are achieved by the formation and minimization of such higher-order components in the probe radiation, the difference frequency of which does not coincide with the difference frequency of the two main measuring components of the first order. In comparison with the known solutions, the processing of spectral information is carried out at the modulation frequency, and not at the doubled frequency; the operating range of OVA has been increased by 2 times in terms of the bandwidth of the tested devices; instead of the standard Pound-Drever-Hall technique used to stabilize the laser wavelength with an additional modulator, the technique of controlling the amplitude and phase of the beating envelope of the main probing components is used; the relative error in the reconstruction of the frequency response of the high-Q optical structure at each point does not exceed 5×10^–5. The obtained characteristics are confirmed by numerical modeling of the developed OVA when characterizing the spectral parameters of a narrow-band fiber Bragg grating. The presented method is structurally simple, does not require the use of various generators to perform its main functions and monitoring functions, and can be used to characterize both selective fiber-optic structures and high-Q optical Fabry-Perot resonators, resonators based on whispering modes, ring active and passive resonators, transparency windows of nonlinear crystals, plasmon resonances, etc.

The article proposes a method for non-destructive testing of optical fiber strength based on estimates of the energy of nonlinear acoustic emission and the tested optical fiber as an acoustic sensor with phase modulation of the optical carrier. Models of the processes on which the method is based are presented. The results of experimental studies are presented. The data obtained from the results of testing the fiber samples using the proposed method were compared with the results of the same samples' measurements by the known 2-point method. The error in relative estimates of the strength of the tested fiber samples did not exceed 3.0%. This allows us to speak about the correctness of the models used and the potential possibility of using the proposed method for non-destructive testing of the strength of optical fibers, as well as the prospects for the development of the application of the considered approach for measuring optical fibers strength in cable.

In this paper, an algorithm is proposed for sorting delivery lengths of optical cables according to the probability of failure and selection of the cable's lengths with the highest probability of failure on the route of the communication line section. The implementation of this algorithm is presented for two examples of cable lines built using the "micro cable-in-microtube" technology. The data obtained as a result of processing demonstrate the possibilities of applying the proposed algorithm in practice.

This work presents fast and simple method for estimation of the reflection at the connection of two singlemode optical fibers with contaminated fiber optic connector ferrule end faces via results of analysis of connector ferrule end face photo-image. Proposed solution is based on discretization of mode field distribution and following passage to representation of the mode field overlap integral in the form of finite nested sums. Proposed approach provides ability of taking into account the mode field distortions, occurring due to the optical fiber end face contaminations, by directly overlapping of connector ferrule end face image over discretized mode field radial distribution. We present some results of developed method approbation on really measured fiber optic connections between standard singlemode optical fibers with various order contaminated ferrules.

The paper shows the possibilities of searching for a cable laying route, determining the depth of occurrence and localizing damage sites for cables without metal elements. A description of the methods is given and their potential capabilities are considered. New methods of searching for fiber-optic cable lines and determining the locations of their damage are proposed.

The paper presents the research results to assess the efficiency of using MIMO technique in the tasks of detection and location of nonreflecting events on traces of a group of optical fibers of a cable line. The mean values and standard deviations of the detection probability of a splice closure and also the first described efficiency parameters are calculated as evaluation criterion. Calculations are carried out for different values of cable capacity, repeater spacing and dynamic range of reflectometer. The analysis showed that the use of MIMO technique significantly increases the detection probability of a splice closure on traces of optical fibers of a cable line.

We examined the psychological support of social interaction in the process of team building in the training of specialists in the field of "Physics and technology of optical communication" and "Photonics and optoinformatics". The article justifies the need to develop a methodology using psychological and pedagogical approaches. The results of a diagnostic study of the students' social interaction skills maturity are analyzed. Functional blocks of the methodology "Psychological support for the formation of universal competence" are presented. The project of training programs for team building on the implementation of professional prospects and improvement of the planned plans in the chosen profession is proposed.

The paper provides an in-depth overview of the model of competencies that specialists in the field of "Physics and technology of optical communications" and "Photonics and optoinformatics" need to have from the perspective of educational standards and employers' opinions. It deals with the theory and practice of building a model of competencies in higher education institutions that will give a specialist an insight into their future careers as well as their professional and essential qualities in the field of "Physics and technology of optical communications" and "Photonics and optoinformatics", and how they interrelate and interact.

The paper presents an experimental study of the possibility of constructing a near-infrared atmospheric optical communication system based on a pair of 100Base-TX / 1000BASE-T signal format media converters in the 1000BASESX / LX format with DEM-310GT SFP transceivers. To ensure better stability of the input of radiation coming from the receiving collimator into the fiber cable, the FTB900 SN-Y4 BRANCHED TUBE cable was used. Its cable connector has been modified to match the DEM-310GT transceiver. The collimator of the transmitting radiation is supplemented by a spiral phase plate forming a vortex beam. The influence of atmospheric influence on the data transfer rate is analyzed.

The optimization of decomposition parameters in the problem of selecting distant objects against a starry background based on motion blur (motion smear) is considered. It is shown that this problem is solved in three stages – detection, coordinates estimation, classification. Each of these stages has its own, different optimal ratio of pixel size and lens point spread function. The solution obtained is a specification of Johnson's criteria for the adopted useful signal and background models.

The article provides an overview of the use of space division multiplexing (SDM) technology in radio-over-fiber (RoF) data transmission systems in future high-speed scalable 6G wireless networks. The features of using the SDM technology in the radio access network are analyzed. The application of new specialized few-mode fibers in 6G networks for the useful information transmission is proposed. The results of experimental studies of custom optical fibers designed for vortex mode generation are also presented.