This PDF file contains the front matter associated with SPIE Proceedings Volume 9533, including the Title Page, Copyright information, Table of Contents, Authors, Introduction (if any), and Conference Committee listing.

The article is devoted to the research of a method providing positive chirp of a signal on a long-haul fiber optic line. The modeling of an optical pulse duration and its chirp functions on an offered segment has allowed to estimate the parameters of a segment – distance between regeneration points and capacity level of additional radiation. The method is interesting for high-speed transmission when there is no availability to use the electronic or fiber optic chromatic dispersion compensation modules.

The article contains the results of the impedance measurement of the microwave laser emitter. The diagram of the experimental setup is described. The results of the experiment are shown. The RLC- laser diode module parameters are found. Due to the parameters the amplitude-frequency characteristics are received. Impact of the parasitic parameters of the laser emitter on its frequency responses is researched.

The article presents the modeling results of the of single-channel communication system with using of multiplexing in polarization. In addition, the authors added an overview of current methods to increase the capacity of optical communication systems.

This paper focuses on the technology of compression of light pulse in an optical fiber. Investigated the effects of compression and decompression of the optical linear chirp pulse and define the parameters of optimal pulse. Simulated the rectangular chirp light pulse at different ratios between the parameters of the phase and frequency change.

In this paper the potentiality of nonlinear effects mitigation by increasing of optical fiber core diameter was investigated. The numerical simulation of return to zero differential quadrature phase shift keying optical signals propagation taking into account nonlinear effects was performed. As result the Q-factor dependence from effective mode diameter was obtained for different signal parameters. The results of optical fiber synthesis with given parameters are represented.

Based on coupled nonlinear Schrödinger equation (CNLSE) piecewise regular model of few-mode long-haul fiber optic transmission link with DWDM and Erbium amplifiers is considered. The few-mode fiber optic transmission link model takes into account the loss, dispersion, differential mode delay, nonlinearity and non-regularity. Based on mode coupling theory and Gaussian approximation modification of split-step Fourier method for the numerical simulation of the CNLSE is introduced. Examples of simulation of a few-mode long-haul fiber optic transmission link by this method are presented.

In this paper we demonstrate computer simulation results obtained for the coherent mode division multiplexed (MDM) 5x5 QPSK transmission using principal modes (PMs) of the stepped-index few-mode fiber (FMF) as a basis of independent signal carriers. The output signal recovering and the fiber propagation matrix determination are considered to be carried out in optical domain by means of reconfigurable multibranch diffractive optical elements (DOEs). Both the cases of Gaussian and Nyquist raised-cosine pulse shaping are considered for optical signal modulation. The simulation results show, that the transmission in the basis of PMs in strong coupling regime allows the reliability of the coherent MDM system to be fundamentally improved. As a result, utilization of the optical signal processing for MDM transmission could minimize substantially the DSP circuit complexity required for the real-time recovering of the transmitted signal.

The device for positive chirping of a signal in a fiber optical line is offered. The device is based on two Fabry–Perot resonator with additional fiber optical cannels. If to execute the amalgamator from an erbium doped material, the device will supply amplification of a target signal, which is important for distribution access systems (for example, Radio-over- Fiber systems (RoF)). The device provides selectivity for spectral components of entrance radiation, that allows to operate of chirp. Built-in the converter of length provides in additional fiber optical cannels tuning the chirp under the given size.

We consider nanofocusing of electromagnetic field in the near-field using sharp metallic and dielectric particles with little radius of surface curvature. An ability of extraordinary field confinement is shown theoretically using integral equations and modelling in Comsol. We have offered the scheme of focusing, which consists of prefocuser and nanofocuser. We consider different composition of prefocuser and nanofocuser. It is shown that a size of a focal spot extremely depends on radius of surface curvature. A refractive axicon can be used as prefocuser and metal or silicon nanoparticle can be used as nanofocuser. If the radius of aluminum spherical nanofocuser is 20 nm the radius of the focal spot is λ 400 . That is smaller than it is achieved in previous works.

The article analyzes a wide range of technologies generated by the application of focusators of laser radiation. I give a brief review of the methods of monitoring substrate and forming a diffraction microrelief, optical systems and devices for experimental research of focusators, laser technologies and units on their basis. In particular, I analyze using focusator into the ring for growing single-crystalline fibers in device of mini pedestal, using focusator into a set of rings for information-measuring system of three-dimensional control of grid spacers and other applications of focusators.

The technology of fiber Bragg gratings is used as one of the most applicable technologies for construction of fiber optic sensors and telecommunication systems. Periodic irregular wave resistance located in the guiding waveguide can be regarded as analog of the fiber Bragg grating structure in the field of radio-frequency. Coaxial waveguide can be used as a guide system, so a special case of this structure is the Bragg grating on coaxial cable. Recently, the special structure of sensors were beginning to be used with heterogeneity as a discrete phase π-shift. Based on the properties analysis of the Bragg reflection characteristics of structures with a phase shift in the optical and microwave range shown advantage of using these devices in measuring systems.

We analytically and numerically show that by introducing the asymmetry into the axicon design it becomes possible to generate the longitudinal electric field (E-field) component on the optical axis for linearly and circularly polarized incident beams. Binary axicons with high numerical aperture (NA) are fabricated in three configurations – axisymmetric and spiral ones, and bi-axicon – by electron beam lithography. Experimental measurements for the near-field diffraction of most common and easy to implement incident beams – linearly and circularly polarized – are conducted. The experimental results agree with the theoretical analysis.

An optical scheme of a fiber-fed spectrometer for the near-IR region around 1.5 um is presented. The scheme is based on transmission holographic gratings with aberration correction. Such question as optimization of the diffraction efficiency for the working range and its polarization dependence are considered. All the results are proved by numerical modeling.

We present fast and simple method for calculation the mode field diameter of arbitrary order guided mode propagating over weakly-guiding optical fibers with an arbitrary refractive index profile in the core region bounded by single solid outer cladding. Proposed method is based on modified Gaussian approximation extended to the considered problem. We tested it for prediction the insertion loss at splice of conventional singlemode and multimode optical fibers with precision transversal offset and compared the results with the measured values, getting a close matching.

This work presents method for design of refractive index profile of silica GeO₂-doped graded-index multimode optical fibers 50/125 with low differential mode delay (DMD) for operation at wavelength 1550 nm. Here the objective function is represented as a sum of squares of deviations between points of current iteration group velocity map, which has been calculated over modes with particular orders, and certain reference group velocity value. During the objective function formation it is proposed to take into account only selected excited guided modes, that depend on launch conditions. Some results of introduced method approbation under singlemode Fabry-Perot laser excitation with central and offset launch conditions are represented.

In this paper the possibility of pipeline diagnostics using the optical fiber grid spherical gauge is considered. Constructions of a fiber grid on the basis of multimode fibers and fiber Bragg gratings have been investigated. Breadboard models of different gauge constructions have been implemented and investigated. It has been established experimentally, that the gauge design based on the fiber Bragg gratings possesses higher sensitivity for deformation. However, the gauge based on the multimode fiber is more robust to the temperature influence.

This work presents modification of Gaussian approximation. Here we propose to describe mode field distribution in fiber core by Laguerre-Gaussian functions and by modified Bessel function of the second kind in the fiber cladding. Results of error estimation are presented for equivalent mode field radius calculation occurring due to mode field distribution approximation by Laguerre-Gaussian functions in the cladding region. According to obtained results the error is negligible for low-order modes. However it increases up to 1% and even more for modes with (m + l) > 4, where m is radial and l is azimuthal mode order.

The simple algorithm for taking into account the material dispersion in the calculations of the dispersion characteristics of optical fibers is introduced. In contrast to known solutions based on an approximation of dependencies of Sellmeier coefficients from the impurity concentration the proposed version of algorithm is based on the linear approximation of dependencies of the refractive index of the impurity concentration. The offered algorithm for calculating of the spectral characteristics of chromatic dispersion was tested on the examples of optical fibers with step-index profile. As examples it was considered the optical fiber with a pure silica glass as cladding material and a GeO₂ doped silica glass as material of core and the optical fiber with fluorine doped silica glass as cladding material and pure silica glass as material of core. The comparison of the experimental data with the theoretical curves obtained using known methods and the theoretical curves obtained using proposed algorithms are presented.

In this paper we consider the integrated approach to development of the aero-acoustical methods for diagnostics of aircraft gas-turbine engine flow-through passages by using as the base the passive fiber-optic and location technologies.

The article is devoted to hyperspectrometer modeling based on the use of filters with linearly varying parameters. The point spread function depending on the spectral filter parameters is estimated. The results were obtained by decomposition of the incident radiation on vector Bessel modes. Numerical calculations show that significant deterioration in resolution occurs only in wide-angle optical systems

We propose and investigate a complex hyperspectral image classification method with regard to the spatial proximity of pixels. Key feature of the method is that it uses common and relatively simple algorithms to attain high accuracy. The method combines the results of pixel-wise support vector machine classification and a set of contours derived from kmeans++ image clustering. To prevent redundant processing of similar data a principal component analysis is used. The method proposed enables the accuracy and speed of hyperspectral image classification to be enhanced.

We propose and numerically investigate an all-optical temporal integrator based on a photonic crystal nanobeam cavity. We show that an array of photonic crystal cavities enables high-order temporal integration.

We considered interaction of PMD and Kerr-nonlinearities in the two-channel WDM system to derive conditions of signal improvement due to such interaction. We presented statistics of eye-diagram opening and investigated properties of fiber links providing this kind of signal improvement.

In optical information-measuring systems structured lighting is an important part that largely influences and even determines both used algorithms and hardware. In many cases it is the addition of a structured lighting turns a vision system in measurement system and improves intellectual features of information system. I suggest using a structured lighting for detecting the presence of a train on a controlled track and fixing car-to-car gaps in vision systems on the railway. This approach eliminates the need of special sensors or additional equipment for the specified control and, in conjunction with other decisions of complex technology articulating design of all components of vision systems, allows to increase the maximum speed of trains passing through the checkpoints, to improve significantly the accuracy of the process of recognition of identification numbers of cars and containers, makes it possible to bring the camera closer to the track, to control all roads of the railway station simultaneously under the minimal distance between them.

In this paper, we try to analyze ways and means of amplitude-phase modulation conversion of the optical carrier, measuring “amplitude-frequency” and optical-electronic conversion of the obtained spectral components and their use for the measurement of the instantaneous frequency of microwave signals. The aim of paper is to extend the range of measured frequencies, increase the resolution of the measurements in the "low" frequencies and sensitivity of the measurements in the field of "high" frequencies.

This paper presents the investigate of mechanical loadings applied to the optical cables module structure at low temperatures. Mechanical loads experienced by the optical cable in the process of construction of fiber-optic communication lines, and in the course of their operation, are major factors affecting the reliability and service life optical cable. Over the past few years, optical cable modular design greatly supplanted other modifications, so in this article addresses the evaluation of mechanical loads applied to the modular design cables at low temperatures.

The analysis of reliability of underground fiber optic cables installed directly in ground and in a duct. Based on the calculation of the life time of the optical cable it is expected that the life time of armored optical cables installed directly in ground will be smaller than for the cable installing in duct.

The results of measurements of number of fibers with attenuation increasing in the loose tube measured at various deformations of the tube are presented in article. In experiment all fibers in the module were at the same time controlled. By results of experiment function of probability of optical fiber attenuation increasing due to optical cable loose tube is obtained.

Results of research of the gel-filled optical cable at low temperatures are presented in article. It is shown that stiffness of tubes of an optical cable increases at low of temperature more strongly if in tubes there is a hydrophobic filling compound.

Results of the analysis of technical and economic indicators of installation of the cable line on two technologies – traditional with the underground optical cable and duct optical cable are given in article. It is shown that installation cost of the "duct cable" technology is slightly higher. But this technology allows higher reliability of an optical cable in exploitation therefore its application is economically more effective.

This paper demonstrates the possibility of determining the equivalent, in terms of the coincidence of differential mode delay diagram, refractive index profile of the multimode optical fiber by direct method and responses to pulse action, which are measured at the output through single-mode optical fiber. As an example, by using the measured data of the refractive index profile of the sample of multimode optical fiber and based on Gaussian approximation model impulse responses at the output of a short length single mode fiber, which was jointed with multimode fiber, were calculated. Multimode and single mode fibers were jointed with axial misalignment. Responses to impulse action were calculated for several values of axial misalignment of single-mode and multimode fiber. From the responses by the direct method the equivalent refractive index profile was determined. Comparison of the results of calculations of the differential-mode delay diagram for the investigated and the equivalent refractive index profiles showed their good agreement.

This work presents method for computing the equivalent graded refractive index profile of multimode optical fibers via differential mode delay diagram reconstructed by few-mode pulse response at the receiver end of researched fiber. Equivalent refractive index profiles for commercial multimode fibers of Cat. OM2 with central defects as peak and dip were computed. Results of proposed method approbation are represented.

The investigation of polarization reflectometry sensitivity to detection and localization of new events in fiber optical lines is carried out. The results of numerical simulation and experimental measurements are represented. The estimation of localization accuracy for different events depending on polarization characteristic is represented. The algorithm of data processing and method for measurement using polarization controller are represented.

In this paper, we propose a new algorithm for monitoring the state of the fiber-optic link using polarization effects. The necessity of this work is because currently in operation is a very large number of fiber-optic cables with expired or expiring operation. This means that they are actively developing microcracks and other local defects. In this paper we propose a method for continuous monitoring of optical fiber communication cables.

The controllable storage and on demand retrieval of the microwave pulses by using the photon echo quantum memory approach based on a spin frequency comb of inhomogeneous broadening (SFC- protocol) have been demonstrated. We have used an electron-nuclear spin ensemble of tetracyanoethylene anion radicals in toluene which has a natural periodic structure of narrow electron-spin resonance (ESR) hyperfine lines. On-demand retrieval of the stored field has been realized by using two pulses of the magnetic field gradient of an opposite polarity which hold the electron spins in a dephased excited state during the storage time. The obtained experimental results demonstrate promising properties for coherent controlling the electron-nuclear spin ensemble of radicals in liquid that could be useful for implementation of room-temperature broadband quantum memory.

The paper is devoted for presentation of training course for applications and construction principles of poly-harmonic (two-frequency or four-frequency) cw laser systems for characterization of different nonlinear scattering effects in fibers and reflection of devices based on fiber Bragg gratings (FBG) in down-hole telemetric sensor nets, which are widely used in down-hole telemetric systems. In particular, we’ll speak about evaluation of Mandelstam-Brillouin gain contour, Raman scattering contours and FBG reflection spectra characterization. Investigation methods and approaches are based on the unity of resonant structures of generated fiber responses on exciting and probing radiation or external physical fields for all given effects. The main decision is based on poly-harmonic probing of formed resonance responses. Training course united idea is software defined approach for down-hole parameters characterization in spite of measuring conversion principles.