This PDF file contains the front matter associated with SPIE Proceedings Volume 12743, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Traditional LANs use L2 switches, L3 routers, and xEthernet-based connections using UTP 5 copper cable. At the same time, it becomes increasingly difficult to meet the emerging requirements for increasing network bandwidth to meet the traffic requirements of new high-speed applications, reduce costs for the installation and maintenance of cable infrastructure, to reduce the power consumption of the equipment and the space occupied. To solve these problems, it is proposed to use passive optical local networks POL (Passive Optical LAN) based on PON technology. POL will not only bring great benefits to customers and does not require changes in service scheduling and network connections of user terminals, but also supports all the functions provided in a traditional LAN. POL is one of the practical approaches to implement the FTTE (Fibre to the Everywhere and Everything) concept proposed by ETSI. The article presents a draft POL design for a hotel. A feature of the POL architecture is a single fiber optic infrastructure for all services required on hotel. One fiber optic gateway is used, and ONUs with built-in router and Wi-Fi access point are located in each guestroom, providing all services (LAN, Internet access, Wi-Fi, IP-telephony, video surveillance and IPTV). In addition, special ONUs are located throughout the common areas with additional services such as emergency hotlines and IP cameras for video surveillance.

In this paper, the types of modulation that support high-capacity transmission in 5G networks and beyond are discussed. Different types of digital modulation (DP-PSK , DP-QAM) and their impact on the quality of received bits are discussed. Appropriate methods are suggested for transmitting the signal for distances up to 200 km and with an acceptable number of bit errors per unit time (BER) with acceptable values of acceptable values of signal power to the noise power, (SNR) ratio . with totally transmission bit rate approximately 6.4Tb/s . So , We describe the architecture of passive optical networks with coherent wavelength division multiplexing (PONs) Which helps to support fifth generation networks and beyond.

In this article we present the results of an experimental study of a periodically poled lithium niobite (PPLN) crystal designed to generate sub-terahertz radiation based on the process of difference frequency generation using two optical carriers of close frequencies. This crystal was specially designed for this frequency range. The resulting generation efficiency turned out to be relatively low, however, here we present the proof of concept.

The article discusses the possibilities of using holography for parallel transmission of information in communication channels. Existing channels use serial transmission. At the same time, there is an effect that can be considered as a parallel transmission of information – holography. To transmit a hologram over a communication channel, it is necessary to transpose the space-time matrix. In this case, the information is deployed in space, and two local points are used in time – the moment of the formation of the object and the moment of the formation of the hologram. One option is optical holography, where an array of lasers pointed at the receiver matrix forms an interference pattern on it. The second option is the use of radio holography, the third is the transfer of the communication channel from the space-time domain to the time-frequency domain. To do this, one can use the transfer of the information block into a linear array of the spectrum in the frequency domain (time-frequency transposition). In this case, the hologram is aligned in the frequency space – the shape of the hologram corresponding to the transmitted information block contains the signal spectrum. The approaches considered are a problem statement for developing methods for parallel holographic transmission and creating communication channels that practically do not have an upper bandwidth limit. The theoretical limit is the transmission rate of a hologram – the amount of information contained in a three-dimensional image of a complex object, within the duration of one period of an electromagnetic wave.

The report presents a theoretical and numerical analysis of the sharp focusing of a displaced Laguerre-Gauss single-ring mode with circular polarization based on the Richards-Wolf formulas. Expressions for the amplitude of the field components in the focal plane are obtained, while the case of “+”-polarization is considered in more detail. In addition to the general expression, the formula for intensity along the horizontal axis is given separately. It is more convenient for determining the displacement parameters than tracking them from the intensity pattern. Expressions are given for calculating the displacement value based on the intensity profile of the longitudinal component for large values of the vortex order. It is shown that for explicit asymmetry visualization it is advisable to use modes with a small but non-zero number.

This article is devoted to the study of the possibility of controlling the antenna array using chirp optical radiation. The general control scheme is considered, the control device is proposed, its detailing is performed. The calculation of the device parameters has been performed. General recommendations have been made.

In this paper, it is proposed to use Brewster angle refraction on a conical surface to form an azimuthally polarized beam. After reflection from the conical interface of the two media, the azimuthally polarized beam is conically divergent. An azimuthally polarized beam has a vortical phase dependence. In order to collimate the output beam and make it plane-parallel, it is proposed to use one, two or three conical surfaces combined in one element. The outer surface is used to collimate the converted beam, which significantly distinguishes the proposed element from previously proposed approaches. We have named the refractive optical elements Volcone, Tetracone, and Tricone. The Volcone produces ring shape beam and the Tricone and Tetracone produce round shape beam. The polarization states of the rays when passing through the interface of the media, as well as polarization transformations using the proposed elements using our own developed ray tracing program taking into account polarization, are investigated. The description of the polarization state was carried out using Jones notation. The Volcone is fabricated by diamond turning, in which an internal conical cavity is made. The paper describes a method for calculating the path of beams through refractive conical elements, taking into account phase and polarization conversions. The Volcone is experimentally made of polymethyl methacrylate on a computer numerical control milling machine. The experiment with the Volcone demonstrates the effectiveness of the proposed element. We present Tricone geometry calculation for the following manufacturing.

The article is devoted to the study of issues related to the developments of methods for manufacturing 3D refractive index profiled fiber and fiber-compatible structures. Based on the results of the analysis of published works, it was established that there are no tested approaches with generality to solving this problem. Therefore, the method proposed by the authors seems relevant, which can be classified as a technique for bulk transformation of material properties, which makes it possible to approximately select, and then adjust (with refinement) the volumetric refractive index profile of the selected area to the simulated value. In this article, the authors present the results of the formation of a guiding structure along the boundary of a profiled area. The method of three-beam UV burning and the method of focused ion burning were studied. It has been found that in the second case, significant differences in the refractive index can be obtained. Therefore, the second method may be of interest for the manufacture of large-sized components.

This work presents overview of technological issues concerned with drawing of twisted silica microstructured optical fibers. We present results of drawing tower modifications with developed and verified technological modes, that provide fabrication of silica microstructured optical fibers with induced chirality up to extremely high twisting order of 800 revolutions per meter (rpm). Thus, a work package using the original designer technical solutions for upgrade the adapter for supplying overpressure to the cane holes of the microstructured optical fiber (MOF) was carried out. Hence, the target increase in the twisting speed in the cane feed unit to 2000 rpm is ensured while simultaneously target overpressure feeding to the cane holes, which prevents the hole collapsing in the process of MOF drawing. The reliability of the adapter design and the high reproducibility of the specified cross section structure for the MOF at lengths of more than 50 meters with a twist period of 500 rpm have been experimentally confirmed. For the first time in the Russian Federation, prototypes of "stable" chiral MOF lengths (more than 50 m) of a different configuration with a maximum induced twisting of 500 rpm and MOFs prototypes with structure stability at lengths of less than 50 m with a strongly induced chirality of up to 790 rpm were fabricated. The geometric patterns of these fibers are also presented in this work.

Seven years ago, we proposed the concept of addressed fiber Bragg structures (AFBS), which simultaneously perform the functions of: a complexed sensitive element based on two FBGs (2λ-AFBS) with different Bragg frequencies or FBG with two π-phase shifts (2π-AFBS), the difference frequency of which is the AFBS address and the value of it is invariant to measured physical fields; a two-frequency laser radiation source, which can operate as in reflection, so as transmission mode respectively to structure above, a self-multiplexed set of sensors, if the difference frequency will be unique for each AFBS, enabling their address multiplexing. In this article, we consider the ontology of AFBS, including the parent structures with 2λ- or 2π-components, successor AFBS with three spectral components and various combinations of difference frequencies: symmetrical and asymmetric, performing the functions of the addressing and converting information signals to the low-frequency region at the same time, along with the functions of rejecting collisions caused by the relative movement of structures relative to each other during measurements. The subjects of interrogation of these structures and their calibration are discussed as well as prospects of AFBS further development based on common tasks born by ontology formalization and decisions of applicability tasks.

Fiber Bragg gratings (FBGs) have attracted considerable attention and have been used to measure various physical parameters. The best known is the use of FBGs to measure structural strain in a direction parallel to the optical fiber. However, it is also possible to use an FBG to measure the load in the direction transverse to the optical fiber. The paper presents scientifically based principles for constructing and results of experimental demonstration of polarization fiber optic sensors for monitoring of transversal load of a new type built on two addressed fiber Bragg structures (AFBS) with a microwave photonics interrogation. AFBS with two phase shifts have two ultra-narrow transmission peaks in the reflection band, which determine its address, expressed in GHz. When a transverse load is applied to AFBS, the transmission peaks will be divided into two due to the difference in the change of the fiber core refraction indices. The distance between the wavelengths of the separated peaks with two polarizations will change when the transversal force changes. The measured dependence between the value of the transverse force and the frequency of the beat-generated microwave signal shows very good linearity. The new sensor has the possibility to increase the resolution and sensitivity of measurements, as well as temperature compensation through the use of various AFBS of wavelength type. The range of measured forces is up to 100 N, the absolute measurement error is 0.1 N, frequency separation sensitivity is 0.1 GHz/N.

To eliminate the limitations of known optical thermal anemometers, distributed and point fiber optical flowmeters, we determine the prerequisites to design a microwave photonic dual-FBG differential sensor for flow velocity and direction based on like-FBG gauge – phase shifted fiber Bragg gratings or addressed fiber Bragg structures of wavelength or combined wavelength-phase type. In addition, we offer an economical microwave photonics addressed interrogation scheme that does not require complexed optical spectral analysis. The article evaluates the model of proposed sensor and its characteristics in static and dynamic flow conditions using two different schemes for set-up of similar or different gauges. The aim of the work is to search for scientifically based principles for the development of microwave photonic flow and flow direction fiber optic sensors, with the possibility of increasing the resolution and accuracy of measurements in the region of low flow rates, as well as temperature compensation. To achieve the aim, the typical with similar gauges and non-typical with different gauges liquid flow sensors based on the measurement of differential pressure by optoelectronic methods are considered, and the problem setting for determining the flow direction using microwave photonics approaches is given as one of the options for their development. A universal mathematical model for a microwave photonics approaches is considered and the requirements for choosing an element base other than classical FBGs are determined. The possibilities of using flowmeters with a phase π-shift FBG and addressable fiber Bragg structures as sensors, which at first glance could improve their metrological characteristics, but are not widely used for this, are discussed. The obtained results and directions for further research presented in conclusion.

The paper presents the results of a study of a computer model and a prototype of a probing radiation shaper for radio-photon vector analyzers. The measurement of the dynamic range and the level of nonlinear distortions of the generated radiation was carried out. The limitations of the available CAD for the design of radio-photonic systems in terms of the discrepancy between the obtained results and practical ones are revealed.

A technological feature of optoelectronic oscillators (OEO) is the combined use of solid-state components of modern RF and microwave optoelectronics, fiber light guides and the traditional element base of microwave equipment. According to the principle of operation and the scheme of construction of the OEO is similar to the classical radio frequency oscillator with a delay line in the feedback circuit. A feature of his work is the multi-frequency nature of the generated oscillations, for which the conditions of amplitude balance and phase balance are met. Of particular interest is the process of self-excitation of the oscillator from noise to stable signal generation.

This paper analyzes the prospects for applying optical beams carrying orbital angular momentum (vortex beams) for sensing. We give short retrospectives on environmental properties one can measure with vortex beams, such as liquids turbulence, temperature, and movement. We also propose a new method based on photonic integrated circuits for determining liquids’ refractive index and turbulent properties using vortex beams. The essence of the method is to measure the refractive index and detect the vortex order simultaneously. The developing sensor consists of two microring resonators: a vortex emitter, which also acts as a refractive index-based temperature sensor, and a receiver. This method can potentially increase the measurements’ accuracy and measure the liquid’s turbulence.

The paper proposes a method for generating a given radiation field from the end face of a round open dielectric waveguide. The method is based on solving a system of two Fredholm integral equations of the first kind with respect to the components of electric and magnetic fields tangential to the aperture plane.

This article analyzes the influence of the accuracy of manufacturing microring resonators on the characteristics of sensors based on silicon-on-insulator and silicon nitride platforms of integrated photonics. We estimated a deviation of 8 nm in increasing and decreasing the waveguide width. The results indicate that inaccuracies in the width of the waveguides lead to a resonant shift, but they do not affect the sensor’s sensitivity.

High-frequency signal generators are required in such applications as telecommunications, radar, medical equipment, remote control, probing, radio astronomy, and spectroscopy. One can use an optoelectronic oscillator on a photonic integrated circuit in these applications due to its ease of implementation and low phase noise level. This article considers an optoelectronic oscillator with a phase shifter as a phase modulator implemented in a photonic integrated circuit to simplify the photonic integrated circuit design. The simulation results show that this system can generate microwave signals with a high signal-to-noise ratio (at least 35.27 dB). The side mode suppression ratio was up to 5.94 dB lower than the Mach-Zehnder modulator scheme. This proposed scheme can be used for microwave signal generation in various telecommunication applications and in interrogation tasks.

The article describes an approach to simulating a microring resonator structure on the silicon nitride integrated photonics platform when exposed to various hazardous to human health gases. We simulated various gases by changing the refractive index of the medium surrounding the resonator from 1 (vacuum) to 1.001768 (CCl₄). The microring structure resonant wavelengths varied for various gases, and the quality factor, sensitivity, and intrinsic detection limit were determined. The simulation results show that it is possible to detect a wide range of gases hazardous to human health, including carbon tetrachloride, mercury vapor, carbon monoxide, and nitrogen monoxide, using the developed sensor. However, it is impossible to distinguish the last two gases based on the results of the current work using the SiN platform. Coatings are one of the potential ways to improve the designed sensor for detecting these gases.

The paper proposes a photonic integrated circuit (PIC) design for multi-channel swept-source optical coherence tomography (SS-OCT) with a high-scale elements integration on the chip. The PIC contains a tunable reference arm, four spaced apart sample arms, a k-clock based on an unbalanced Mach-Zehnder interferometer, an OCT interferometer, and balanced photodiodes. The PIC is developed for a silicon nitride manufacturing platform, providing minimum losses. The simulation results demonstrate the possibility of simultaneous reception of OCT data from four different points of the studied tissue sample, which can significantly increase the scanning speed.

The study of noise generated by a system homodyne detection of laser radiation was made when random noise is recorded at the outputs of anoptical beam splitter after differential detection of signals. We studied the dependence of noise parameters on the length of the signal sequence sample and the effect of detrending using wavelet analysis. The NIST test suite was used to evaluate the degree of randomness of the generated noise sequence.

In this paper, we studied the properties of two-photon quantum states of light that emerge due to spontaneous parametric downconversion in a nonlinear waveguide with periodically poles structure. The spectral and entangled properties have been studied mainly for photon pairs whose spectra is located in the near-infrared range. We found that it is possible to select the geometric parameters of the structure of a lithium niobate nanowaveguide in such a way that the two-photon quantum state in the near-IR range will have a spectrum width of about 180THz.

In this research, the process of focusing of femtosecond cylindrical vector beam with second order by binary zone plate is studied applying the frequency-dependent finite-difference time-domain method. We have demonstrated that the material of zone plates significantly influenced on the electromagnetic field formed at the focus. We also shown that, tight focusing of a second-order cylindrically polarized laser pulse produced an energy backflow in the focal plane of phase and aluminum binary zone plates. However, there is no reverse energy flux in the focus of binary zone plate made in thin gold film.

In this paper, we theoretically and numerically consider the sharp focusing of a laser beam whose polarization pattern in the initial plane is a superposition of a cylindrical vector beam of order m and a homogeneous linear polarization. At the focal spot of such a beam, for odd m, there will be areas with elliptical or circular polarization with alternating directions of rotation. For even m at the focal spot, the field is linearly polarized at every point and has no transverse energy flux. These beams can be used to create a micromachine in which two microparticles in the form of gears are captured in the focal spot of the beam into neighboring local areas in which the energy flux twists in various directions, and therefore, these gears will also twist in various directions.

This work presents results of test series, performed for earlier on designed and successfully fabricated silica few-mode microstructured optical fibers (MOF) with six GeO₂-doped cores, induced twisting 100 revolutions per meter, typical “telecommunication” outer diameter 125 μm, core diameter 8.7 μm, air hole diameter 4.6 μm, pitch 7.2 μm, and core quasi-step / graded refractive index profiles with height 0.0360/0.0275, respectively. Part I introduces attempts for splicing of typical telecommunication optical fibers and fabricated samples of MOFs by commercially available field arc fusion splicer kits and results of differential mode delay map measurements, performed for laser excited large core (multimode) optical fibers with core diameters 50 and 100 μm, jointed via free space to described above 2 m long pilot samples of 6-GeO₂-core MOFs at both receiving and transmitting ends under laser-excited gaussian optical pulse launching with precision offset conditions, while Part II is concerned with researches of spectral responses, measured for fiber Bragg gratings, recorded in these MOFs.

This work introduces first time fabricated spun silica microstructured optical fiber (MOF) with inclusion of seven GeO₂-doped capillaries, placed in the central part of MOF cross-section, and induced twisting up to 730 revolutions per meter. Part I discusses technological issues for manufacturing of described complicated twisted fiber optic structure, while Part II presents some results of test series, performed for successfully manufactured twisted MOF pilot samples with typical hexagonal geometry under hole radius 4.40 μm and pitch 9.80 μm, outer “telecommunication” diameter 125 μm, and center part, formed by seven hollow GeO₂-doped ring cores with inner radius 2.50 μm, pitch 8.80 μm and refractive index difference Δn=0.030. Following measurements were performed: measurements of transmission spectra under various twisting order, far-field laser beam profiles, some attempts of fusion splicing of typical telecommunication optical fibers and fabricated MOF with insertion loss estimation, and spectral response measurements of both single and group WDM (Wavelength Division Multiplexing)-channels of commercially available telecom WDM-system under inclusion of 2 m length MOF into various spans of short-range lab fiber optic link.

This work introduces first time fabricated spun silica microstructured optical fiber (MOF) with inclusion seven GeO₂-doped capillaries, placed in the central part of MOF cross-section, and induced twisting. While Part I discussed technological issues for manufacturing of described complicated twisted fiber optic structure, presented some pilot samples of described MOFs with various twisting order and measured their transmission spectra, Part II describes some results of results of experimental researches, performed for successfully manufactured twisted MOF pilot samples with typical hexagonal geometry under hole radius 4.40 μm and pitch 9.80 μm, outer “telecommunication” diameter 125 μm, and center part, formed by seven hollow GeO₂-doped ring cores with inner radius 2.50 μm, pitch 8.80 μm and refractive index difference Δn=0.030 with induced twisting 130, 300 and 730 revolutions per meter. Following test series were performed: measurements of far-field laser beam profiles, some attempts of fusion splicing of typical telecommunication optical fibers and fabricated MOF with insertion loss estimation, and spectral response measurements of both single and group WDM (Wavelength Division Multiplexing)-channels of commercially available telecom WDM-system under inclusion of 2 m length MOF into various spans of short-range lab fiber optic link.

This work presents results of test series, performed for earlier on designed and successfully fabricated twisted silica fewmode microstructured optical fibers (MOF) with six GeO₂-doped cores. While Part I introduces results of differential mode delay map measurements, Part II is focused on researches of spectral responses, measured for fiber Bragg gratings, recorded in these multi-core MOFs with core graded refractive index profiles and induced twisting 100 revolutions per meter. Specially setup for spectral response measurement for described complicated fiber optic element was developed, that provides selected alignment of matching singlemode optical fiber with particular single core of MOF via free space and reducing of reflection by precision 8 angle cleaving. Comparing analysis of measured spectral responses confirmed written FBGs in 2 of 6 cores, and demonstrated potentiality of fabricated complicated structure, containing multi-core MOF with FBG, for applications in multichannel fiber optic sensors with spatial division multiplexing technique.

It is proposed to use an iterative algorithm based on a ring spectrum and a lens to calculate a diffraction-free beam with a given transverse intensity distribution. In this work, we calculated and studied diffractive optical elements (DOEs) that form some primitive non-diffraction distributions (for example, a square and a triangle, as well as more complex grayscale distributions). It is shown that the iterative algorithm is stagnating, i.e. the number of iterations is directly related to the root mean square error. The mean square deviation of the formed transverse intensity distribution from the given primitive does not exceed 0.006 for a triangle primitive, 0.015 for a square primitive, and 0.07 for a high-contrast halftone image.

The article considers the problem of identification of a linear dynamic model of optical images based on the registration of one-dimensional optical signals. A number of theorems defining the conditions for the identifiability of a linear dynamic image model in the classical sense are formulated and proved. Further, on the basis of proven statements, blind identifiability conditions are formulated for the special case of a discrete system with one input and multiple outputs, which are superimposed on the components of the optical system transfer matrix.

Intelligent automatic diagnosis of diseases, which acts as a recommendation system for diagnosticians, reduces the burden on medical personnel and potentially reduces the impact of the human factor. This circumstance is especially true against the background of rejuvenation of retinal diseases, in particular age-related macular degeneration. In this article, we analysed how neural network models and dataset dimensionality affect the effectiveness of an intelligent diagnostic algorithm for three stages of age-related macular degeneration based on optical coherence tomography images. We identified the advantages and disadvantages of convolutional and recurrent neural networks when dealing with each stage of the disease, as well as different dataset sizes. Based on the obtained information, we concluded the most effective neural network architecture in terms of achievable specificity and sensitivity values, as well as the impact of augmentation for increasing the original dataset on the overall generalization ability of the algorithm.

The subwavelength ring gratings with a gradient refractive index (GRIN) of the substrate and variable height are calculated and investigated. The grating period is 1.05λ. Two variants of changing the refractive index n of the GRIN substrate were considered: from the maximum n in the center to the minimum n at the edges and the reverse case. The propagation of light through the proposed 3D microstructures was modeled using the finite difference time domain method. The possibility of reducing the focal spot size is shown using the proposed 3D microstructures, and the formation of an extended light needle and optical traps is also demonstrated.

In this paper we consider method, proposed by the authors, for pre-processing X-ray images based on the convolutional neural network. Multilayer computed tomography scans of the lungs are ubiquitous, used to detect pathology, such as covid-19 diseases. The proposed method consists of computed tomography lung image segmentation, the volume of interest localization at these scans, distinguishing between denser structures, such as bones, and less dense ones, such as blood vessels. A comparison of the pathological formations classification quality was made on images with different degrees of preprocessing on large data sets. Image Classifier software was developed for demonstration of x-rays preliminary processing opportunities in the context of their class association forecasting. The developed software showed quite good results. Maximum value of the average probability reached 77.5%. The number of epochs required to achieve the specified quality level is four.

This study aimed to investigate the potential application of distributed fiber-optic acoustic sensors for speech recognition amidst complex audio backgrounds. The experimental measurements were carried out on the mock-up room with a fiberoptic link. The possibility of application the fiber-optic distributed acoustic sensor for localization of sound source and recognition of musical and human speech signals amidst complex audio backgrounds was demonstrated. The signal detected by DAS provides good quality of music composition recognition and clear speech recognition. The difference in spectrum of signals detected by microphone and DAS was analyzed. The signal noise ratios were calculated for test speech signal with different average levels and its influence on the speech recognition was analyzed.

Lighting devices (LD) operated in vibrating conditions result in nonuniform, in terms of time and space, energy density of the light flux generated. As a result, shadow distortions take place on the illuminated surface with varying frequency. For this reason safety of transport vehicles (TV) equipped with LD and operated in darkness hours and in vibrating condition is reduced. LD illuminating parameters are adjusted and controlled in accordance with the relevant documents in static conditions. In this case nonuniformity of LD light flux due to TV vibration is not taken into account. Nonuniformity of LD light flux is increased thanks to roughness of the deformed LD reflective or refracting surface. The purpose of this study is to develop the parameters indicative of nonuniformity of the light flux of LD to dynamic, nonstationary loading. The methodology of the study included two stages: Resonance frequencies were determined for a real-time 3D LD model; for frequencies, the value of which attributed to the frequency range of TV vibrations, deformations of the diffuser for one light source (incandescent lamp) and deformation of the baseplate carrying a set of light-emitting diodes (LEDs) were determined; by applying the laws of geometric optics light fluxes for the deformed diffuser and the deformed baseplate were determined; simulative nonuniformity of the light flux was researched on a screen located at the distance away from LD which is prescribed by the relevant specification documents. Both smooth and rough refracting surfaces of LED secondary optics were studied, as well as the deformed surfaces of LD reflecting diffusers. Digital images of the light flux nonuniformity was converted using mapping method into an information pattern, which constituted a shape with the area of 1 and with borders in the form of orthogonal interval of finite lengths. Isoperimetric parameters – a perimeter and mass center – were used for numerical parametrization of the intervals limited by the borders of the information pattern. The proposed method – using the example of analysis of the designs of a railway locomotive headlamp and an airplane landing light – proved high sensitivity to minimum changes in time and space of the light flux of LD operated in vibrating conditions. The proposed method allows to account for roughness of LD optical surfaces as a contributor to the light flux nonuniformity. Isoperimetric parameters were used for numerical parametrization of nonuniformity of the light flux. This method allows to optimize LD design and the technology for manufacturing its optical elements with the purpose of ensuring the requisite nonuniformity of the light flux generated.

The study goal was to evaluate the possibility of automating of optic coherent (OCT) images analysis and to develop a model for precise differentiation of nature of intracoronary atherosclerotic plaques using deep neural networks. At the first stage of the study, special software was developed that allows the experts to mark 16 different types of pathologies in the intracoronary images obtained from OCT. The following pipeline was used for image preprocessing: 1) image smoothing using a Gaussian filter (noise reduction), 2) image binarization using a threshold of values determined according to the Bradley-Roth adaptive (local) binarization method; 3) interpolation of missing values; 4) vascular wall determining; 5) transformation of polar coordinates into Cartesian ones. 534 images were collected for analysis, obtained as a result of OCT of the main 3 coronary vessels of the heart. Two models (convolutional neural networks with the AlexNet and ResNet-18 architecture) were trained to detect the pathologies. The results demonstrate high accuracy of the both models: plaques detection 0.72-1.00; lipid plaque - 0.875-0.929 and fibrous differentiation - 0.893-0.929.

The basis of the Fifth Generation Fixed Networks (F5G) is planned to be a new concept of using fiber – the concept of Fiber-To-The-Everywhere-and-Everything (FTTE). Its practical implementation largely depends on the degree of use of the fiber in various applications. To assess this degree, ETSI has proposed using the Fiber Development Index (FDI). In 2002, the methodology for calculating FDI changed somewhat. The index now includes the following metrics: fiber to the premise’s coverage, fiber to the household penetration, fiber to the business penetration, mobile cell site fiber penetration, advanced WDM technology investment. Index also quantifies the overall broadband quality of experience improvements driven by that investment, namely: median download speed, median upload speed, median latency and median jitter. The article provides a methodology for calculating the FDI and analyzes it’s for Russia.

The article discusses the use of Distributed Acoustic Sensing technology in locating underground all-dielectric optic cables. DAS uses fiber optic cables to detect acoustic vibrations along the cable's length caused by digging or drilling, allowing for precise identification of the cable's location and path without excavation or other intrusive search methods. DAS provides high-resolution data over long distances, making it more accurate than traditional search methods like geo-radar or GPS markers. The article proposes a localization algorithm for detecting the path of all-dielectric optical cables using DAS technology, based on a combination of approximate and point estimates of cable location. The algorithm is tested on a testing ground of a section of an optical communication line, demonstrating the ability to determine the area of optical cable laying with a radius of up to 5 meters in real-time.

During maintenance of fiber optical communication lines the cyclic seasonal temperature variations can cause movement of optical fibers in loose tubes and redistribution of curvature. This is especially true for aerial suspended optical cables there significant “pushing out” of fiber from tubes in optical closures can be observed after years. In previous papers two methods for estimation of optical fiber curvature distribution based on reflectometric measurement on two wavelength and using polarization reflectometry were proposed. The results of estimation of optical fiber curvature distribution in all-dielectric self-supporting cable during cyclic temperature variation in climatic chamber are represented in paper.

The experimental study of attenuation distribution changes of optical fiber in cable due cyclic temperature variations is represented in paper. It was observed that attenuation coefficient changes due temperature effect varies in irregular manner, that can be caused by redistribution of fiber curvature along cable. The fiber segments corresponding to the outer cable coils on the drum are most affected by temperature cycling, that can be due high thermal inertia of cable drum. The length of fiber segment with noticeable attenuation rising is approximately 500 m. The irregular local attenuation changes demonstrate the optical fiber curvature redistribution in cable due cyclic temperature variation and also can be used for estimation of variation of mechanical stresses.

Future 6G networks will be able to support a wide range of services with different technical requirements and in different frequency bands. To achieve this goal, the use of radio over fiber (RoF) technology is an important foundation for both the transport architecture and the hybrid radio-optical centralized architecture or 6G fronthaul cloud radio access network (CRAN). At the same time, the 6G generated signal processing technologies and modulation schemes must meet the stringent requirements of a mobile data network. In this paper we estimate energy efficiency of DFT-s-OFDM in RoF systems in terms of peak-to-average power ratio (PAPR).

This article proposes a method for improving energy efficiency by reducing the peak power of the emitted signal in systems with DFT-s-OFDM for fiber-optic segments of future mobile networks of the 5G and 6G generation, based on the use of an improved "raised cosine" shaping filter, as well as ZT-DFT-s-OFDM technology for improved energy efficiency. Various new waveforms and modulation schemes are presented that would be both energetically and spectrally efficient. The analysis of the ratio of the peak signal power level to the average level for signals with DFT-s-OFDM in its various modifications in radio-optic networks is presented, various technologies for the formation of DFT-s-OFDM are analyzed depending on the method of access to the subscriber, such as DFDMA, LFDMA and IFDMA, considering the bandwidth extension factor.

The up-to-the-date electrical systems for beamsteering of the phased antenna arrays are widely used; however, possessing significant drawbacks, including high losses, electromagnetic interference, and high power consumption. To overcome these challenges, microwave photonic systems, both discrete and integrated, have demonstrated outstanding potential. In this context, we discuss the two primary methods for beamsteering, i.e., true time delay (TTD) and phase shift (PS). This paper provides simulation results for a four-channel photonic integrated circuit (PIC) for beamsteering based on the TTD method. The PIC design could be implemented on any fabrication platform. The results demonstrate the approach’s feasibility and its potential to improve the performance of phased array antenna systems.

An actual task of quantum communications over long distances is the creation of a bright source of photon pairs operating at standard wavelengths of fiber optic communication lines. In this work, we experimentally investigated the spectral and correlation characteristics of photon pairs generated on the phenomenon of spontaneous four-wave mixing in a highly nonlinear photonic-crystal fiber with a wavelength of one of the photons near 1.5 μm. The demonstrated source can be used as an efficient single photon generator at a telecommunications wavelength with prediction and tuning over a wide spectral range.

The article substantiates the need to include soft-skills development methods and technologies in the educational process. The information of methods and approaches to the development of creative (imaginative) abilities has analyzed. The program of training sessions on the formation of creative abilities (an effective and practical component) is presented. The efficiency of the formation of master students’ creative abilities in the field of optical communication system through the training sessions, activation of divergent functions of intelligence is considered.

The requirements of the mass consumer and educational market impose great restrictions on the cost of hardware-software demonstrators with relatively low requirements for the characteristics of the quantum key distribution process. This means that these devices do not have to be advanced and, as such, can provide a dramatic reduction in size, weight, and power compared to other quantum key distribution systems. The article presents the stages of development and creation of an experimental prototype of a hardware-software demonstrator of a universal quantum key distribution system that implements existing methods based on amplitude and phase modulation, as well as the proposed method of tandem amplitude-phase modulation of an optical carrier. The evaluation of the technical, economic and operational characteristics of the hardware-software demonstrator was carried out; practical recommendations were formulated for its development, creation and operation, as well as for the choice of an import-substituting element base, which ensured its low cost and the possibility of wide use at various research and educational sites, including World Skills youth championships and Future Skills process. In addition, the proposed demonstrator, embedded in a desktop computer, can act as access devices that can be connected to a terminal combined with a quantum network node to replenish a secret key store, which can then be used to encrypt daily activities on conventional platforms such as the Internet.