High bit rate laser-based data transmission over silica optical fibers with enlarged core diameter in comparison with standard singlemode fibers is found variety infocommunication applications. Since IEEE 802.3z standard was ratified on 1998 this technique started to be widely used for short-range in-premises distributed multi-Gigabit networks based on new generation laser optimized multimode fibers 50/125 of Cat. OM2…OM4. Nowadays it becomes to be in demand for on-board cable systems and industrial network applications requiring 1Gps and more bit rates over fibers with extremely enlarged core diameter up to 100 μm. This work presents an alternative method for design the special refractive index profiles of silica few-mode fibers with extremely enlarged core diameter, that provides modal bandwidth enhancing under a few-mode regime of laser-based data optical transmission. Here some results are presented concerning with refractive index profile synthesis for few-mode fibers with reduced differential mode delay for “O”-band central region, as well as computed differential mode delay spectral curves corresponding to profiles for fibers 50/125 and 100/125 for in-premises and on-board/industrial cable systems.

Connection setup with guaranteed quality of service (QoS) in the optical virtual private network (OVPN) is a major goal for the network providers. In order to support this we propose a QoS based OVPN connection set up mechanism over WDM network to the end customer. The proposed WDM network model can be specified in terms of QoS parameter such as blocking probability. We estimated this QoS parameter based on the hose-model OVPN. In this mechanism the OVPN connections also can be created or deleted according to the availability of the wavelengths in the optical path. In this paper we have considered the impact of the number of wavelengths on the computation of blocking probability. The goal of the work is to dynamically provide a best OVPN connection during frequent arrival of connection requests with QoS requirements.

This work presents method for design of precision positioning scheme for mode division multiplexing (MDM) system channels at the end of link few-mode optical fiber with enlarged core diameter. Proposed solution is based on combination of well known overlap integral method and earlier on developed Gaussian approximation modification generalized for analysis of silica weakly guiding optical fibers with one outer solid cladding and arbitrary axially-symmetric refractive index profile. The last one provides a passage to analytical expressions for any order mode coupling coefficients under taking into account set precision radial misalignment. By using presented method we computed launching parameters of 5-mode MDM multiplexer channels to the end of few-mode optical fiber samples with enlarged core diameter up to 42 μm and reduced differential mode delay provided by specially designed graded refractive index profile. According to computation results, it is able to transmit the almost total one MDM channel mode power to only one optical fiber particular mode with the same azimuthal order by corresponding combination between mode field diameter and precision radial misalignment.

In this paper physical effects caused by macro- and micro bends of optical fiber including additional mode-dependent loss, mode coupling and spurious mode excitation in fiber MDM-system are considered. The effects described below can dramatically decrease capacity and maximum data rate in such systems because of inevitability of fiber bends due to system exploitation thus making MDM-system commercialization much more difficult and expensive. Mathematical approach used to describe these effects and applied in the simulation model is based on well- known refractive index profile approximation [1] of bent step-index fibers and mathematical field coupling model [8].

This article analyzes architectures and techniques of the optical networks with taking into account the cognitive methodology based on continuous cycle “Observe–Orient–Plan–Decide–Act–Learn” and the ability of the cognitive systems adjust itself through an adaptive process by responding to new changes in the environment. Cognitive optical network architecture includes cognitive control layer with knowledge base for control of software–configurable devices as reconfigurable optical add-drop multiplexers, flexible optical transceivers, software–defined receivers. Some techniques for cognitive optical networks as flexible–grid technology, broker–oriented technique, machine learning are examined. Software defined optical network and integration of wireless and optical networks with radio over fiber technique and fiber–wireless technique in the context of cognitive technologies are discussed.

We present method for design of refractive index profile for silica GeO2-doped graded-index few-mode optical fibers with reduced differential mode delay and suppressed mode nonlinearity due to extremely enlarged core diameter up to 42 μm. Proposed solution is based on earlier on developed modified Gaussian approximation generalized for analysis of silica weakly guiding optical fibers with single outer cladding and arbitrary axially-symmetric refractive index profile, that provides ability to derive analytical expressions for guided mode delays. Therefore the objective function is represented as a sum of squares of deviations between mode staff delays and reference value corresponding to refractive index profile of current iteration. Based on developed method we performed computation for various combination of the reference mode delay and first iteration profile parameter. Some results of desired graded-index profile for a few-mode optical fibers 42/125 providing differential mode delay minimization over central region of "C"-band are represented.

In a number of previous papers authors have introduced quasiparticle of radio- and optical systems. We have called this quasiparticle by ‘radion’. The basis for this is the representation of Green’s function of equation of quasioptics by Feynman integral. It means that radion has quantum mechanical properties. In particular in approximation of quasioptics one can interprete amplitude of electromagnetic field as amplitude of probability of radion. In the paper presented we describe new features of radion which we have established recently namely we have found some exact solutions of evolutionary equation for field of quantum mechanical averages of momenta of ensemble of radions possessing by average of momentum in initial state depending on average of coordinate in it. We demonstrate three the simplest solutions from this set of exact solutions. These solutions in the form of power series on dimensionless time are applicable up to the moment of gradient catastrophe. For representation of solutions of parabolic equation in approximation of quasioptics Remizov method of quasi-Feynman formulae has been used. All these results due to suggested by us physical analogy are valid for free one-dimensional nonrelativistic quantum mechanical particle too. Also in the framework of Remizov method a number of new formulae for statistical radiophysics and optics has been obtained. ‘Natural’ fractality of radio- and optical systems has been discussed.

Experimental bench, which provides high-speed data transmission for IR-UWB Radio-over-Fiber systems on the basis of Gaussian pulses, is presented in the paper. Experiment setup and results are described and discussed.

Wireless part of the laboratory bench, implementing IR-UWB Radio-over-Fiber system, is described in the paper. Experimental prototype of fractal antenna radiating system (FARS) is considered, various transmission modes of the laboratory bench, which allow to investigate technical specifications, are described. Research results are presented and analyzed.

We study theoretically the propagation of vortex laser beams in a random medium. The study is based on the extended Huygens-Fresnel principle with the generation of a random field, using the fast Fourier transform. The simulation shows that the stability of vortex beams to fluctuations of an optical medium falls with rising order of optical vortices. A coherence length (radius) of the random medium is of great importance. The coherence radius extension affects adversely the conservation of a beam structure in the random medium. During further free-space propagation, increasing coherence enables to reduce negative effects of fluctuations for beams with high-value topological charges.

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.

The equations were obtained to estimate the pulse power losses of broadband light pulses caused by material dispersion in an optical fiber. It was found that the dispersion caused by the extension of a signal bandwidth leads to decreasing a signal base as well as the noise immunity of a system, which uses broadband pulses.

The paper discusses the questions of creating a mathematical model for studying the extension of a broadband pulse caused by material dispersion of an optical fiber while matched compression is also taken into account. It was shown the dependence of the dispersion widening of optical broadband signal on the optical fiber material dispersion coefficient. It was established that we can neglect dispersion impact in the case when the pulse frequency band is less than the coherence band of an optical fiber.

We present modified technique for differential mode delay map measurement. Here according to well-known methods a fast laser pulse is also launched into a tested multimode fiber (MMF) via single mode fiber (SMF), which scans core of MMF under precision offset positions. However unlike known technique formalized in ratified standards, proposed modification differs by addition scanning of the output end of tested MMF by short tail of SMF. Therefore for each radial offset position at the input/output MMF ends, the shape of pulse response of launched optical signal is recorded, that provides to get more informative differential mode delay map. This work presents some results of experimental approbation of proposed modified technique for differential mode delay map measurement.

The use of laser technologies in the production of optical fiber requires a careful choice of optical systems for positioning and transforming the laser beam. The purpose of this research is to determine a possibility of the redistribution of the laser beam power using diffractive optical elements. It was determined that for a radius of the focusable beam R_f = r_f =2.2×10^-2 m, the length of the focal spot will be increased to a value L =13.6×10^-3 m, which is 1.2 times larger than R_f = r_f =1.8×10^-2 m. In this case, the intensity of the laser beam at the centre of the focal spot, q₀ , and the maximum value, q_max , decreased by 1.1 times. An approximation of function q(x, y) by polynomials of degree n =5and m =3 was performed. It is shown that the maximal relative error of approximation does not exceed 4%, and the relative error of approximation in the centre of the focal spot does not exceed 3%. Presented equations can be used to calculate the intensity distribution in the focal plane of diffractive optical elements.

The paper discusses options for using semiconductor optical amplifiers in the radio-over-fiber systems. The theoretical evaluation of the optical parameters of the amplifier, modulator and detector implemented on the basis of the semiconductor optical amplifier, as well as estimates of the parameters of the device using a semiconductor optical amplifier as a multifunctional optical device power modulator detector.

An action survey of the optical elements class named by generalized parabolic lens is cited in this paper. The approximately-analytical and numerical analysis of radiation transformation realized by the generalized parabolic lens is described within the limits of different theories: geometrical-optics and wave (paraxial and nonparaxial). The types of refracting aspherical surfaces described with power function are defined on base of the geometrical-optics analysis. The surfaces allow forming characteristic intensity distributions on an optical axis. A paraxial propagation of laser beam with an initial arbitrary power phase function is described with approximate analytical expressions which are agreed qualitatively with the geometrical-optics analysis. The obtained expressions are precise for exponents 1 and 4. A nonparaxial analysis is implemented on base of calculation of the Rayleigh-Sommerfeld integral with qualifying corrections. It is shown that essential growth of intensity in the focus happens at the exponent value from 1 to 2, and the maximal intensity is achieved in a middle of the range.

New polarization converter for transforming the circulary polarized laser modes into cylindrical vector beams (CVB) including beams of higher orders is proposed. The generation of CVB in birefringent crystals is studied analytically and experimentally in paraxial and non-paraxial regimes. At sharp focusing (in the non-paraxial case) two focuses corresponding ordinary and extraordinary beams are formed along the crystal’s axis. The results are extended to the generation of higher-order radially and azimuthally polarized mode beams. Using the simulation the possibility of fabricating crystal-based devices suitable for application in fiber optics was shown. The results of the experimental study on the generation of cylindrical vector beams in a crystal of Iceland spar agree with the results of the simulation.

The results of experimental and theoretical studies of fiber-optic delay lines with different types of intensity modulation of the optical carrier are presented. It was considered the using in the delay lines either optical radiation sources of constant intensity, modulated by microwave signal by using an external electro-optical modulator or laser diodes with direct modulation of the pump current. The results of an experimental study of the characteristics of the oscillator microwave signals, constructed using both types of fiber-optic delay lines are described.

In this work, narrowband pass and broadband pass filters are designed based on TiO₂-SiO₂ multilayers. These filters are used in observing planetary nebulas and emission nebulas. They are designed by using open source software open filter and optimized by using needle synthesis method (addition of thin layers called needles and analyze transmission till the best result achieved). Also results were cross-checked by using matrix method. The transmission of these filters is in the range of 486-501 nm (Oxygen-III and hydrogen-β) with a maximum transmission of 95%. Also it has a second peak at 656 nm for hydrogen-α where transmission reaches 87%.

This paper presents the investigation of the necessary conditions for the non-linear excitation of higher order modes in the single mode optical fiber with step index profile. The required peak optical power for the non-linear excitation of higher modes was calculated. The dependency of this optical power from the normalized frequency of a step index optical fiber was studied. Calculations were performed for optical fiber with core of doped silica glass by germanium and cladding of pure silica glass. It was shown that for such a single mode optical fiber under pulse duration of less than 500 fs it is possible to create the necessary conditions for the nonlinear excitation of high order mode before the laser damage.

In this paper is presented an approximate solution for the fundamental mode of the step-index optical fiber with taking into account the Kerr nonlinearity. The solution is obtained by a known method of Gauss approximation. The derivation of the characteristic equation for the equivalent mode spot radius and analytical expressions for the propagation constant and its first, second and third derivatives are described. The analytical formulas for time delay and chromatic dispersion are given too. Based on the obtained analytical solution there were calculated the dependencies from the optical power the parameters of fundamental mode for the sample of the step-index optical fiber.

Sunlight can be used a source of light in buildings and automobiles, however infrared wavelengths in sunlight result in heating. In this work, Infrared Reflective Coatings are designed using thin films to transmit visible wavelengths 400~700 nm while reflecting infrared wavelengths above 700 nm. Three different design approaches have been used, namely single layer of metal, sandwich structure and multilayer design. Four metals (Ag, Au, Al and Cu) and two dielectrics (TiO₂ and SiO₂) are used in this study. Designs with Ag show maximum reflection of Infrared wavelengths in all designs. Sandwich structures of TiO₂-Ag-TiO₂ on substrate with 22 nm of thickness for each layer show the maximum transmission of 87% in the visible region and maximum reflection of Infrared wavelengths.

This paper describes functional principles of a device for optical signal splitting and chirping. The offered device is to fulfill functions of such optical signal distortions compensation within FOCL RoF as linear attenuation (LA) and chromatic dispersion (CD); and it should also split optical signals for its feeding to radio emitting components, compounding aerial array (AA), and control radio emitting antenna lobe. In the meantime the device for optical signal splitting and chirping can inject losses into transferred signal, though they should be within tolerant values for conventional FOCL components.

This article examines the devices for optical signal splitting and chirping device modeling. Models with splitting and switching functions are taken into consideration. The described device for optical signal splitting and chirping represents interferential splitter with profiled mixer which provides allocation of correspondent spectral component from ultra wide band frequency diapason, and signal phase shift for aerial array (AA) directive diagram control. This paper proposes modeling for two types of devices for optical signal splitting and chirping: the interference-type optical signal splitting and chirping device and the long-distance-type optical signal splitting and chirping device.

We discuss a four-Sector transmission Polarization Converter that enables the conversion of linearly polarized incident light into an azimuthally polarized beam. The resulting azimuthally polarized beam is characterized by a phase shift of π between the diametrically opposite beam points. Using scanning near-field optical microscope we experimentally show that by placing a Fresnel zone plate of focus 532 nm behind the four-sector micropolarizer, light can be focused into a subwavelength focal spot with smaller and larger sizes measuring FWHM = 0.46λ and FWHM = 0.57λ Numerically obtained focal spot of the transverse E-field component, which is measured by our scanning near-field optical microscope, has diameters FWHM_x = 0.42λ and FWHM_y = 0.59λ.

Diffractive optical elements capable of transforming the wavefront in a predetermined manner, with high efficiency may be apply in recording systems and reading information, and also its transmission in the optical range. To improve the efficiency use of diffractive optical elements is expedient to determine the requirements for their adjustment and the accuracy of beam setting parameters forming. As an example, considered the use of a diffractive optical element for transmitting high-power laser beam for the purpose to conducting the appropriate heat treatment of the process object. It was determined that the permissible error of alignment of the optical element is no more ΔU₁ = ΔV = 0.18·10^-3 m, the accuracy of the focused beam parameters should not be lower Δr_Φ/r_Φ = 3.1 %; ΔR_Φ/R_Φ = 2%, and the permissible value of rotation angle Φ error of the diffractive optical element is ΔΦ = 2.3⁰. To solve this problem a diffractive optical element is characterized by adequate values of allowable errors. Keywords: diffractive optical element, laser beam, adjustment, accuracy

We simulate impulse propagation in all-optical temporal integrator based on a photonic crystal nanobeam cavity. This cavity (6 x 0.5 μm) is tens times smaller in size than Bragg grating or microring resonator proposed as an optical integrator earlier. The demonstrate good correspondence between numerical and analytical results.

In this work, the modeling of the propagation of the pulsed focused Gaussian beam through the phase optical element, designed to divide the incident beam into two closely spaced light spots, has been carried out. The simulation has been performed on the base of the finite-difference time-domain method, implemented in the software MEEP. The analysis has been shown a noticeable pattern change in the focal region using short pulses in comparison with a long signal, however, the structuring of the pulse laser beam by using the phase optical element passes successfully.

Experimental research in deposition of thin CdTe films was carried out using the resistive dynamic vacuum evaporation method. While forming thin CdTe films, temperature parameters of a substrate varied. Parameters of obtained CdTe films were investigated using Raman spectroscopy, scanning profilometry and scanning electron microscopy. The measured results showed high quality of thin CdTe films deposited on the substrate at temperature of 300°C and 450°C.

This work presents results of experimental approbation of earlier on proposed modified fiber optic stress sensor based on a few-mode effects occurring during laser-excited optical signal propagation over silica multimode optical fiber (MMF). Modification is concerned with a passage to quasi-interferometric scheme realized by two multimode Y-couplers with equalized arm lengths improved by fiber Bragg grating (FBG) written on preliminary formed precision macrostructure defects in silica multimode graded-index optical fibers and special offset launching conditions providing laser-based excitation of higher-order modes. The “arms” of quasi-interferometer are two equalized lengths of MMF Cat. OM2 with great central dip of refractive index profile and strong pulse splitting due to high differential mode delay (DMD). We tested FBGs with Bragg wavelength both 1310 nm and 1550 nm written over tapers or up-tapers preliminary formed in short pieces of MMF Cat. OM2+/OM3 and further jointed to the end of one of the arms before output Y-coupler. Researches were focused on comparison analysis of pulse responses under changing of selected excited mode mixing and power diffusion processes due to stress distributed action to sensor fiber depending. Here we considered FBGs not only as particular wavelength reflector during spectral response measurement but also as local periodic microstructure defect which strongly effects on few-mode signal components mixing process also improved by combination with macro-defect like taper or up-taper that should provide response variation. Some results pulse response measurements produced for different scheme configuration and their comparison analysis are represented.

This work presents method for performing precision macro-structure defects “tapers” and “up-tapers” written in conventional silica telecommunication multimode optical fibers by commercially available field fusion splicer with modified software settings and following writing fiber Bragg gratings over or near them. We developed technique for macrodefect geometry parameters estimation via analysis of photo-image performed after defect writing and displayed on fusion splicer screen. Some research results of defect geometry dependence on fusion current and fusion time values re-set in splicer program are represented that provided ability to choose their “the best” combination. Also experimental statistical researches concerned with “taper” and “up-taper” diameter stability as well as their insertion loss values during their writing under fixed corrected splicer program parameters were performed. We developed technique for FBG writing over or near macro-structure defect. Some results of spectral response measurements produced for short-length samples of multimode optical fiber with fiber Bragg gratings written over and near macro-defects prepared by using proposed technique are presented.

We propose a geometrical optics approach to calculating the eikonal function of a light field on the assumption of generating a desired intensity distribution in a given focal plane region. To solve the focusing problem in a more efficient way, we modify a conforming rectangles method used to design diffractive optical elements (DOE) to focus into plane regions. The novelty consists in a technique for reconstructing the eikonal function based on the known ray mapping relation between the DOE points and focal plane points. Results of focusing into a rhomb are presented. Simulation results show high quality of focusing, also corroborating the efficiency of the proposed method.

In paper we present low-complexity feed-forward algorithm for digital signal processing in coherent optical 16QAM systems, employing adaptive filtering for decreasing linewidth phase noise of coherent laser. Simulations show performance that using dual polarization for 16 quadrature-amplitude modulation (QAM) transmission is possible for laser beat linewidths of ΔfT_s = 0.3 ∙ 10^-3 and ΔfT_s = 7.9 ∙ 10^-5 when soft-decision phase estimator is employed.

In this article the problem of image analysis in unmanned aerial vehicle on-board system for objects detection and recognition with the help of energy characteristics based on wavelet transform is described. The approach of salient points extraction based on wavelet transform is proposed. The salience of the points is substantiated with the energy estimates of their weights. On the basis of wavelet transform salient points extraction the method of image contour segmentation is proposed. For further image recognition the salient points descriptors constructed with the help of wavelet transform are used. The objects detection and recognition system for unmanned aerial vehicles based on proposed methods is simulated using the simulation platform.

The recognition system is observed, where the information is transferred by images of symbols generated by a television camera. For descriptors of objects the coefficients of two-dimensional Fourier transformation generated in a special way. For solution of the task of classification the one-layer neural network trained on reference images is used. Fast learning of a neural network with a single neuron calculation of coefficients is applied.

In this work the single surface plasmon-polariton was obtained by using frequency-dependent finite difference time domain method for the radial polarized and vortex beams at 532 nm, which were propagating through the silver nanoring on substrate from silica glass, placed in an aqueous medium. The height and width of device were equal to 20 nm and 215 nm respectively. The intensity of surface plasmon-polariton was four times higher and three times higher the intensity of the incident radiation for case of conventional and vortex beams respectively. The full width at half maximum of the nanojet was near 160 nm for each cases. The presented design can be used for manufacturing of highly integrated optical devices and circuits used in high-speed communication applications. The results also can be used to design devices that allow capturing and moving the particles in water or other biofluidics.

This article has been described some features of processing multidimensional optical signals, which have been taken in real condition video surveillance of the railway carriages. Exactly: there are the choice region of image for speed measuring, the restore missed measurements, compensation of the camera vibration. The result is speed measurement algorithm of the extensional objects (the object does not contain in video frame fully), which is used for simplify operator working: control carriages braking on hump yard, making consignor list, control conditions of carriages detention.

The theoretical analysis of optical signal propagation through two-lens imaging system based on double finite Hankel transform of order m was performed. The computation of eigenfunctions of the system considered. This computation gives an opportunity to analyze distortion of the optical signal transmission based on the approximation by functions of this set.

We investigated one of the technologies of forming microrelief of diffractive optical elements. The technology is based on using catalytic mask in off-electrode plasma. We have developed a software that allows to evaluate some important parameters of this technological process. First, it is the evaluation of numerical values of concentration profiles "vacancies" and semiconductor atoms in the melt. Second, it is the evaluation of time for irradiation the "metal - semiconductor" structure to achieve the desired depth and the doping concentration of the semiconductor atoms in the melt layer. This enabled to determine the best modes for generating a predetermined height of diffractive microrelief.

Transformation of Bessel beams formed by amplitude diffraction axicons in the x-cut of a uniaxial crystal is investigated experimentally. It is shown that the propagation of the beam in the crystal is accompanied by complex astigmatic and polarization transformation. For polarization of incident radiation parallel to the optical axis of the crystal the output beam has a rhomboidal outline filled with regularly situated intensity maxima.

The problems of synthesis and application of fiber Bragg gratings with special spectrum shapes in measurement and information channels of quazi-distributed fiber optic systems for climatic test systems are introduced. In particular, gratings with concave, triangular symmetric and triangular asymmetric spectrum shapes are considered, also the new poly-harmonic methods of its interrogation are presented. Projects of system decisions and results of experimental researches of its blocks are discussed.

The results of experimental study on the main technological aspects relating to a full production cycle of 50/125 μm silica multimode graded-index fibers with the central defect of the refractive index profile realized as a large dip are presented. Preform synthesis conditions for controllable implementation of the mentioned defect via MCVD method are analyzed and optimized. The effect of geometrical irregularities, induced by drawing optical fibers under the manual maintenance of the outer diameter stability, on attenuation has been explored. Applying the Weibull theory, a statistical evaluation of mechanical properties, particularly tensile strength, of the optical fibers drawn at various temperatures has been conducted.

In this paper, we consider a number of different methods that form the modern approach to the development of aircraft GTE’s noise suppression systems at service conditions. The herein-presented efficient noise suppression system on the base of fiber optic sensors makes it possible to reduce pulsations at the exhaust nozzle exit and noise levels at the engine outlet section.

This article describes the design principles of optoelectronic system (OES) for instantaneous frequency measurement (IFM) of microwave signals based on the use of amplitude-phase modulation conversion of single optical carrier into symmetrical dual-frequency signal for additional frequency separation, its modulation by unknown frequency and subsequent “frequency-amplitude” measurement conversion in Fiber Bragg Grating (FBG) with Gaussian reflection profile. Such approach allows increasing of measurement resolution at low frequencies.

In this article, we present the results of research of photonic systems for spectrum analysis of the SHF-band radio signals based on "frequency-amplitude" transformation in contours of amplification or absorption of stimulated Mandelstam- Brillouin scattering (SMBS) approximation in single-mode optical fiber. Using of such systems as a means of spectrum analysis of the SHF-band radio signals allows us to eliminate many of the shortcomings of similar systems.

One of the important characteristics of the optical cable, affecting its operating parameters, is stiffness. It is known that the stiffness of the optical cable increases at low temperatures due to increase in stiffness of the individual elements of the cable: outer and inner jacket, PBT loose tube and etc. However, as shown by the results of the research, the hydrophobic filling, used in optical cables, also influences on the optical cable stiffness at low temperatures. Results of researches of influence of a hydrophobic filling on stiffness are given in article.

Optical Reflectometer (OTDR-Optical Time Domain Reflectometr) of various types are widely used in almost all stages of the fiber-optic communication systems, from production of fiber optic cable to the construction of fiber-optic communication lines and their operation. OTDR provides a quick and easy diagnosis of the state of fibers, cables and fiber-optic communication lines in general. A new method of analysis allowing visually detect traces of welding with low loss.

In present paper is considered the method for measuring the excess fiber length in the loose-tube optical cable. This method based on measurements of backscattering characteristics with one polarization of optical fibers under sub-zero temperature. The correctness of the method was evaluated by the errors of linear approximation of the dependence of the excess fiber length from temperature under climatic test of optical cable delivery length at sub-zero temperatures. The results of the method verification are presented in this paper.

In this paper an application of Raman reflectometry for distributed temperature measurement on overhead power lines was represented. The modification of standard remote fiber test system scheme and requirements to software was proposed. The results of experimental measurements at fiber optical test set and signal processing algorithm was represented.

This paper presents an analysis of the data measurements of excess fiber length in the loose tubes of optical cable during the post-process quality control of ready-made products. At determining estimates of numerical characteristics of excess fiber length method of results processing of direct multiple equally accurate measurements has been used. The results of experimental research of the excess length value at the manufacturing technology of loose tube remains constant.

The article examines the process of formation of communicative competencies of optic and fiber optic communication systems specialists; the role of communicative competencies is examined in the structure of professionally important skills, together with the contents of professional activity. The stages of empirical research into formation of communicative competencies have been presented, and the values of statistical reliability of data have been provided. The model of formation of communicative competency using interactive technology has been developed based on the research done, and main stages of model implementation and motives of formation of communicative competency have been highlighted. A scheme of "Communicative competence as a base of future success" training session has been suggested as one of the basic interactive technologies. Main components of education that are used during the stages of the training cycle have been examined. The statistical data on the effectiveness of use of interactive educational technologies has been presented; it allowed development of communicative competency of specialists in the field of optical and fiber optic communication system.

The paper considers the concept of fiber-optic communication lines (FOCL) maintenance. Performance criterion of FOCL technical maintenance was proposed. For the first time the algorithm for evaluation of the FOCL maintenance efficiency at telecommunication specialists training was applied.