Fast, frequent, accurate and reliable measurements of physical factors such as temperature, stress or strain play a key role when it comes to ensuring the smooth operation of processes in many domestic, commercial and industrial constructions or devices. For example, most fabrication devices and production process rely on temperature and stress measurements to operate; and most large buildings depend on a series of temperature sensors to control the heating or cooling to maintain the temperature. Photonic crystal fibres (PCF), constitute a class of optical fibres, which has a large potential for number of novel applications either in the telecom or in the sensing domain. Analysis of sensing characteristics of different photonic crystal fibre structures, including effective index and mode field distribution, photonic bandgap, chromatic dispersion, phase and group modal birefringence, confinement and bending losses, sensitivity to temperature, hydrostatic pressure, and other physical parameters are revealed. The benefits of PCF allow fabrication of different types of specialty microstructured fibres such as endlessly single mode, double clad, germanium or rare earth doped, highly birefringent, and many other microstructured fibres as sensor components. The developed characterization techniques of specialty microstructured fibres are reviewed as well. Finally, the new microstructured fibres and fibre component for sensing applications which were designed, fabricated and characterized will be presented. One of the demonstrated components is the effective Bragg grating written in highly birefringent and single mode photonic crystal fibre.

Paper presents the state of advance of the silica glass microstructured optical fibers technology n Poland especially in Department of Optical Fibers Technology Maria Curie Sklodowska University. Only in this Department there are the technological apparatus for advanced investigations on the technology of the silica glass optical fibers. In paper was describe the technology of optical fiber photonic structure manufacturing, high silica glass synthesis from vapor phase with MCVD and OVD methods. Next was describe some kinds of microstructured optical fibers witch technologies elaborated in UMCS in support of own and received from cooperated research teams optical fibers structures, modeling and measurements results.

In this paper the tunable properties of the photonic liquid crystal fibers are analyzed. Both numerical and experimental results on the linear light propagation in the photonic crystal fiber filled with the glycerin-water solution and with 6CHBT nematics are presented. Investigated fiber called as photonic liquid crystal fiber combines the passive photonic crystal fiber host structure and an active nematic liquid crystal material. Such a photonic structure, with a periodic modulation of refractive index, which could be additionally controlled by the temperature and by the optical power, allows for the study of discrete optical phenomena.

Microstructured fibers with small core are successfully used as a medium for supercontinuum generation. Since light can be confined in a small core a high density of energy in the fiber is obtained and stimulate nonlinear effects. Use of lead multicomponent glass allows increasing nonlinear refractive index in the fiber and shape dispersion properties of the fiber. In this case effective broadening of the spectrum can be obtained with less then 1 m of the fiber. In this paper we present properties of photonic crystal fibers optimized for supercontinuum generation.

The paper discusses the influence of temperature and an external electric field on spectral properties of the microstructured optical fibers infiltrated with liquid crystals and also presents a multi-core microstructured liquid crystal fiber showing strong influence of fluctuations of the fiber's dimensions on selective propagation bands. Moreover, we also report the latest experimental results on highly birefringent (HB) photonic crystal fibers (PCF). By using the wavelength scanning method, we have estimated birefringence in an HB PCF without and with liquid crystal filling. Subsequently, the possibility of birefringence tuning in an HB photonic liquid crystal fiber under influence of temperature is demonstrated.

Partially temporary coherent light might be depolarized during propagation in birefringent media. The depolarization depends on coherency of light source DL, birefringence of medium Dn, and azimuth of light beam versus fast and slow axes of medium birefringence (E_x/E_y). Depolarization is caused by polarization mode dispersion, also responsible for spreading light pulses and lowering bandwidth in binary transmission in optical fibers. The depolarization of temporal coherent light is also known in liquid crystals. In this paper we present the results of investigation on depolarization of light in optical fiber structures infiltrated with a liquid crystal.

Double core optical fibre doped with ytterbium was obtained. Low silica glasses without crystallisation effect were presented. The stable glass composition was doped with ytterbium. A set of physical measurements including: DTA, DSC, DL analysis, absorption spectroscopy, visible and infrared absorption edges and thermo-physical properties (thermal stability parameters, refractive index, thermal expansion coefficient, microhardness, density and molar volume) were determined. The absorption bands originated from the ground state to appropriate excited states were observed. Double-crucible drawing technique was applied to obtain double core optical active fibre with NA=0.2. The refractive indexes of core and cladding glasses have been obtained by slight modification of the base glass.

Liquid Crystal (LC) molecules orientation in Photonic Liquid Crystal Fibers (PLCFs) has crucial impact on their optical properties. There are many techniques used for LC molecules orientation control, but most of them are not suitable for application in microstructured fibers, which holes have diameters in the order of one micron. It seems that the only method that could be applied in PLCFs is using of thin photopolymer layers, in which surface anisotropy can be induced in the way of photochemical reactions. In this work experimental results of photoinduced molecular alignment in PLCF with thin polyvinylcinnamate (PVCi) film irradiated with linearly polarized ultraviolet light.

Double-clad photonic crystal fibre structure for laser applications is demonstrated. The double-clad structure of the fibre has the air-cladding with glass bridges of waists less than 500nm. The fibre was produced with phosphate glass and the core region was doped with ytterbium. The fibre was investigated and we found it to be monomode for generation wavelength of 1008nm. Whole fibre producing process including doped and undoped glass manufacturing and fibre drawing was held in Institute of Electronic Materials Technology.

Amorphous glassy materials are of great interest on account of their possible application in optical electronics and glass fiber techniques. In this article lead-bismuth-gallium oxide glasses has been investigated. These materials are characterized by the great value of refractive index and because of absence of paramagnetic ions possess good magneto-optic properties. Measurements of the Faraday effect confirm the occurrence considerable value of the Verdet constant in the group of glasses without rare-earth elements, promising for application in magneto-optic devices.

We propose the method of calculation of the dispersion characteristics and field distribution of the modes in straight and bent multi-core microstructured fibers. The method is implemented for the analysis of the birefringence in dual-core microstructured fibers in dependence on the fiber parameters (air hole diameter, hole separation, distance between guiding cores) and bend radius. The term "birefringence" we understand here in the wide sense including both the difference of the parameters of orthogonally polarized modes (polarization birefringence) and the difference of the parameters of two supermodes with identical field distribution propagating in dual-core microstructured fibers (supermode birefringence). The optimization of the parameters of such fibers using as vector bend sensors is considered.

The technology of Bragg grating formation in tapered regions of telecom fibers is presented. Spectral properties of such Bragg gratings were measured. The tapers were made by thermal heating in the oxy-butane flame. The tapers were kept later in the high pressure hydrogen chamber to enhance the glass photosensitivity. Bragg gratings were formed in the taper region using interferometric pattern using the argon-ion laser 244nm illumination. The transmission spectral characteristics of such gratings show chirp effect. Such advanced devices will be applied as sensors combining the behavior of exposed modal field in the tapers and Bragg gratings properties.

Equations expressing electromagnetic fields in the core, first, second and third cladding regions of WII-type triple-clad optical fiber in terms of twelve constants will be presented. These constants will be determined by applying the boundary condition that the tangential components of electric and magnetic field must be continuous across the core - first cladding, first cladding - second cladding and second cladding - third cladding interfaces. By requiring the continuity of appropriate tangential components set of twelve homogeneous equations will be obtained. These equations have nontrivial solution only if determinant of the coefficient matrix vanishes. This condition leads to the compact eigenvalue equation of the WII-type triple-clad optical fiber.

Series of ten cores photonic optical fibers with different filing factors and different distances between cores was elaborated and manufactured. The measurements of energy transfer and coupling length between cores were done. Obtained results are only in part compatible with known from literature theoretical descriptions of energy transfer in those structures.

A high birefringence in photonic crystal fiber is determined by a lattice type and shape of the holes. Based on the simulations with use of biorthonormal basis method an optimized structure with rectangular lattice and elliptical-like air holes has been selected. In this paper we present expected properties of the fiber. Preliminary experimental results are presented.

Most photonic crystal fibers are made by stacking rods and tubes of a single glass. It is universal procedure to create an air-glass perform which is drawn into a final fiber. It is difficult to obtain an air-glass structure with topology similar to design one in practice. An alternative approach is to replace air holes with glass micro-rods in the considered structures. Use of multicomponent glass allows obtaining a large contrast between microrods and background glass. As a result index guiding and photonic bandgap fibers can be fabricated. In this paper we compare properties of air-glass and double glass structures and report on fabrication double glass structures.

This paper presents technology and characteristic of classic eleven cores single mode optical fibers with linear and circular shape. Manufactured optical fibers can be used in constructions of new class of optical fibers sensors, in witch change of coupling length is used. Those optical fibers are the base for elaboration of the active multicore optical fiber for fiber laser worked in supermode regime.

The paper discusses polarization phenomena occurring in highly birefringent (HB) photonic liquid crystal fibers based on the Blazephotonics HB photonic crystal fiber infiltrated with a liquid crystal. We report on the latest experimental polarization characteristics of microstructured photonic crystal fibers filled with two types of nematic liquid crystals: with low (of the order ~ 0.05) or medium (of the order ~ 0.2) material birefringence. Electrically and temperature-induced tuning of polarization properties have been demonstrated.

We present recent achievements in fabricating a two-dimensional (2D) photonic crystal in the form of a bundle of parallel micro- or nanowires embedded in glass matrix. The method is similar to that of sequential thinning used for fabrication of photonic crystal fibers. We discuss technological issues that aim at preservation of regularity of photonic crystal lattice and uniformity of wire diameters. Proper selection of a melting point of metal alloy and the range of temperatures of glass viscosity leads to reduction of regularity losses resulting from sequential processes of drawing. Measured distributions of crystal lattices, wire diameters and shapes of wires are used to simulate photonic band structure of fabricated crystals. This work is directed toward fabrication of a photonic crystal showing the negative refraction in the near infrared and visible spectral range.

In the paper the preliminary results of the new UV-curable polymer designed for a luminophores' matrix application in the optical fibres' optical sensor investigations have been presented. The conditions of the monomer's photopolymerization, the refractive index of the obtained polymer and its mechanical properties have been examined.

In the paper the preliminary results of the investigation on the possible application of the photo-curable hybrid material synthesis for either optical fibres' protective coatings or UV-VIS transducers' (luminophores in optical fibres' UV sensors) matrices have been described. As the initial synthesis materials the sol-gel silica and UV-curable polyglycols' acrylates have been used. The results of the organic-inorganic polymers' photopolymerization process investigation as well as the properties of the obtained materials have been presented.

The obtained result of broadening spectral bandwidth known as "supercontinuum generation" are described in this paper. This effect is usually obtained by transmission a very short laser impulse through a strongly nonlinear element like optical fiber (especially photonic crystal fiber). Supercontinuum generation can be also obtained by propagation short impulse form (nanosecond pulses from Nd:YAG laser at 532nm wavelength with average power 300mW) through tapered conventional optical fiber (COF) or tapered endlessly single mode photonic crystal fiber (PCF). In these paper we are showing our first result of obtaining this effect.

Technology of tellurite glasses from the TeO₂-WO₃-PbO system rare earth doped has been investigated. This kind of materials possess high transparency in the visible and IR spectral range (up to 6&mgr;m) and low dispersion. Because of introduction of rare earth into glass structure, obtained materials possess very good properties such as: luminescence, high refractive index (higher than 2.0), which is a consequence of high polarizability of tellurium ions. Addition of lanthanum fluoride into glass structure from the TeO₂-WO₃-PbO system change the tendency to crystallization. The effects of the crystallization of glasses from the TeO₂-WO₃-PbO system LaF₃ and other rare earths doped were a subject of the study. Differential thermal analysis, XRD, SEM measurements have been considered in term of rare earth influence. Particular interest present rare earth doped materials. This is caused by their relatively large radius compared to the other compounds as well due to specific luminescent properties of the rare earth ions. In the present work the data concerning the influence of the rare earth on the emission properties of glasses has been presented.

Paper presents technology manufacturing and basics parameters of photosensitive high birefringent photonic crystal fiber made from high silica glasses. It was especially elaborated for Bragg gratings inscriptions. Common photonic optical fibers have cores made from nondoped silica glasses. Therefore Bragg gratings inscriptions are difficult or impossible. In photosensitive photonic optical fibers cores are made from germanium doped silica glasses. In presented fiber core glass was made with MCVD method. Technology of manufacturing of high birefringent photonic crystal fibers are analogous to technology of manufacturing of common low birefringent holey fibers.

The article presents information about shaped optical fibers, which emit radiation light across side, cylindrical surface of optical fiber. Be presented the examples - solutions of measurements of shaped optical fiber.

Article presents new method of design light flux emission in forming optical fibers, with side light emission. This method of design gave a possibility to design side surface of core, to obtain assumption of light flux distribution.

This report shortly describes calculation method related to guiding properties of the microstructure fibres. For the modelling of wave propagation in such fibres in linear and nonlinear regimes the finite-difference vectorial-beam-propagation method (FD-VBMP) has been chosen. This method offers high accuracy and allows investigating longitudinally varying structures or propagation of optical waves with amplitudes varying under the effect of nonlinearity and loss. In order to take into account the effects related to the finite fibre dimensions the transparent boundary conditions (TBC) was used. The Split-Step Local Error method is implemented for correct estimation of the influence of nonlinearity on the wave propagation in microstructure fibres. On the basis of this method the complete algorithm for the numerical simulation of the wave propagation in microstructure fibres under the effect of nonlinearity has been developed. The method allows optimising the structure of photonic crystal fibres (PCF) for maximising or minimising nonlinear effects. Investigation of the properties of a wavelength converter based on a microstructure fibre was carried out using simulation results in the nonlinear case. Modification of the method for optimisation of connection between microstructure fibres and conventional fibres is also considered.

In the paper investigation of properties of liquid layers by using the m-line spectroscopy method has been presented. This method is generally used for investigation of thin solid layers. The layers are usually deposited by evaporating, diffusion or otherwise. Liquid layers have specific character and make possible dynamical change of some of their properties. Especially waveguide layers of liquid crystal can change their physical properties due to their anisotropy. Possibility of obtaining the great power density of light beam in thin planar waveguide in association with great resistance of isotropic layers provides an interesting opportunity to use it in practice. In this paper study of properties of isotropic and anisotropic compounds by m-line spectroscopy method as well as their dispersion with good accuracy has been presented.

We propose the method of all-optical performing the operation of matrix multiplication on the base of the matrix of waveguide ring microresonators. Information is processed immediately when it passes through the optical system, which performs the computation procedures, and with supply of the input data in parallel. The speed of such optical matrix processor is mx1010 vector multiplication per second, where m is the quantity of the used wavelengths that defines the number of rows of the multiplied matrix.

RIB waveguides were fabricated with the use of selective, wet chemical etching of two-component waveguide films SiO₂:TiO₂ which were obtained using sol-gel method. Photoresist was applied as a mask in the process. The etching of the films SiO₂:TiO₂ was carried out in water solutions of ammonia fluoride. The paper presents the determined technological characteristics, power distributions in the obtained strip waveguides and the results of theoretical analysis.

The paper presents silica films of the refractive index 1.267-1.420 and silica-titania films of high refractive index 1.762. Basic fabrication technology was presented as well as the applied measurement methods of refractive index and thickness. The paper provides examples for the application of the elaborated technology for the fabrication of waveguide films, input/output grating couplers and channel RIB waveguides.

The paper presents investigations of multimode interference effects in gradient MMI structures. Investigated waveguides are produced in Ag⁺ ↔ Na⁺ ion-exchange technology. Adaptation of technology process providing improvement of transmission parameters of produced structures is described. The received results and investigation conclusions of obtained images are presented.

The assumptions of Ag⁺-Na⁺ ion-exchange numerical model for strip waveguide formation process in silicate glass were presented. Ag⁺ ions diffused from molten AgNO₃ salt into the glass substrate through the opening in a dielectric or metallic mask previously deposited on the glass surface. The diffusion was speeded up by the external electric field applied during ion-exchange process. As an effect of the mask presence on the glass surface, side diffusion occurred - the range of Ag diffusion in the direction under the mask was comparable to the diffusion range in the direction perpendicular to the glass surface. A space charge formation in the glass layer adjacent to the mask was assumed in the numerical model simulation. Its essential role in side diffusion range was analyzed and the results of the numerical calculations were compared to the experimental data.

In this paper we present a novel concept of NxN switch with full reconfigurability. A rapid prototyping technique based on direct laser writing is considered as an implementation technology. As a first step towards an NxN switch, the experimentally properties of 2x2 switch are investigated. Several samples of the switch with different coupling lengths and distances between the waveguides are developed. Measurement results of coupling efficiency are presented.

At consideration of fiber optic waveguide devices in a lection course the primary attention is paid to analysis features and facilities of planar and cylindrical waveguides in systems of communication, information transmission and procession in real time and also to efficiency of applying semiconductor radiation sources in these systems.

The article presents an overview of elements of opto-telecommunication systems and networks. New developments in the backbone and access layers have been discussed, as well as new types of optical fibers, such as Photonic Crystal Fibers (PCF), holey Bragg fibers, and Plastic Optical Fibers (POF).

Polarization mode dispersion (PMD) in telecommunication fibers is caused by their random birefringence and depends on temporary coherence of the light coupled into the fibers. This phenomenon resulting in light pulses broadening decreases bite rate in telecommunication lines and is expressed in terms of differential group delay (DGD). Measurement of the DGD can be used to estimate the value of PMD, and also for compensation of the PMD value. In this paper the results of PMD compensation by using the Faraday rotator and a longitudinally strained highly birefringent fiber are presented. By controlling simultaneously the longitudinal strain and the Faraday rotator current during DGD measurements almost total compensation of PMD for a 30-km-long telecommunication optical fiber has been achieved.

The paper presents an analysis of graded-index fiber ray tracing used to determine the fiber's transmission bands.

This article is describing phenomenon of dispersion in telecommunication optical fibers. Methods of compensation are presented. Additionally, article contains results of the experiments (dispersion measurement) for optical fiber G.652 and G.655.

This work is devoted to measuring spectral characteristics of narrowband optical sources, and passive and active transmittance of optical elements. The results obtained by using a Fabry-Perot interferometer, heterodyne and automated wavelength dependent loss measurements setups are presented.

The requirements for leser diodes for optical fiber lines of communication and information transfer are considered. There are given data about laser diodes on multi-layered assimetric quantum-well heterostructures as a basis for creation new elements of functional optoelectronics: bistable elements, impulse generators on two and three spased (different) wavelengths, optical modules on two wavelength with equal radiation power, laser with high temperature stability of radiation power and generation threshold.

In this work diffusion processes in thermal connected cylindrical fibers with weakly guiding and circular cross-section, that is telecommunication fibers, have been presented. There have been discussed diffusion distributions of the core dopant of fibers spliced in t ≈ 2000^o C. Gaussian approximations of the core dopant concentration distribution and refractive index in the connecting area of single mode telecommunication fibers have been presented. Theoretical analysis of propagation and loss characteristics for thermally diffused expanded-core (TEC) of single mode telecommunication fibers has been performed, as well. Consistence of theoretical calculation results with experimental data, achieved on the basis of connecting telecommunication fibers with significantly different parameters, has been proved.

Simulation of splicing process of fibers with large effective area A_eff with standard telecommunication fibers is presented in the article. The aim of the simulation was to design the process of diffusion in spliced fibers in order to compensate radiuses of mode fields of spliced fibers. The simulation showed that refractive index profiles both in fibers with step and step (standard telecommunication fibers) index refractive profile reach, after appropriate design of diffusion process, single diffusion maximum, that may be approximated with Gaussian distribution. The results of estimation of loss of above mentioned splicings were presented. Adjusting of mode field radius and length of transit areas TEC (Thermally Diffused Expanded Core Area) was taken under consideration.

Thermally diffused areas of telecommunication single mode fiber core reduce loss of fiber-to-fiber or laser-tofiber couplings indeed. Loss of such area is small if it remains single-modal. In the work, for step, Gaussian and power refractive index profiles, for which fundamental mode LP01 distribution can be approximated by Gaussian function, the so-called equal volume profiles were given. For these profile forms, it has been shown that the fibers remain single-modal independently of changing values of core radius e.g. after diffusion. It has been shown that because Gaussian profile approximates well diffusion distribution, this thermally diffused core area, which has constant quantity of dopant in the diffusion area, remains single-modal.

In the paper, we presented the results of the research on the properties of erbium doper fiber optical sources. We discussed properties and presented results of investigating single mode lasers, focusing on the problem of a beam oscillations at the radio frequencies range. An original method leading to the increase of power efficiency was described. We presented some methods and problems concerning multiwave sources with a special respect to resonant and nonresonant ring structures. We demonstrated results of investigation of a non resonant loop configuration with a quasi steady state operation free of RF components. Results of measuring mode-locked erbium ring lasers were shown.

With the aim to apply vacuum deposited polyaniline (PAN) films as sensing elements of fiber -optic sensors (FOS), the technology of polymer deposition that gives a possibility to obtain conductive emeraldine PAN form by standard protonation methods has been developed. The influence of deposition temperature on refractive index and spectral characteristics of films is specified. On the base of the results change in PAN films optical properties with the change in pH value of the medium, pH level (as well as ammonia, CO) FOS are elaborated. The distinctive feature of sensor optical response is its high sensitivity to pH value, such as, due to increase in pH changes of optical adsorption are observed that is especially high at 500-550nm and 800-900nm of spectral range. For a FOS processing analysis, we carried out measurements of sensor optical response to pH value in two wavelengths (540 nm and 900 nm). Obtained results give us a possibility to suggest an application vacuum deposited PAN films as FOS sensitive element for a pH value determination. It was estimated that FOS has high reversibility of optical response due to redox reaction, that take place on modified fiber part. The inertial FOS parameters are within a minute range.

As results of the carried out investigation of vacuum deposited polyaniline (PAN) films, it was found that the index of refraction of deposited films changes with the change in the angle of incidence of laser light; in other words, PAN films are optically anisotropic. In particular, if the deposition temperature T&agr;=180⁰C, the minimum and maximum refraction indeces are 1.810 and 1.758 respectively; when T&agr;=360⁰C, they are 1.785 and 1.754 respectively; and when T&agr;=400⁰C, they are 1.786 and 1.755 respectively. Such results show that the rate of films deposition increases with the increase in deposition temperature; in particular, when T&agr;=360⁰C and the deposition time is 40 minutes, the film thickness d=353 nm; when T&agr;=400⁰C and the deposition time is the same, the thickness was 400 nm. As results, by means of variation in PAN films deposition technology, it is possible to control optical characteristics of films, and thin has a wide range of application. Due to redox reactions index was also observed. Such films are of prospects as active elements of integral and fiber optical devices.

Structural and optical characteristics of polyaniline films of different thickness obtained on the surface of optically transparent SnO2 electrode by means of electrochemical polymerization method have been investigated. It is found that the increase in thickness of films from 140 to 540 nm leads to crystal formation increase in optical density in the spectral range of 650-800nm. Polyaniline films obtained under optimal conditions show stable optical response and can be used as sensing elements of optical sensors.

A new fiber optic, pulse pressure sensor with a Bragg grating, in the structure of which the operating principle of the Hopkinson bar is applied, is presented in the paper. The delivery of the measured pressure to the sensor is realized by means of a measuring head with truncated cone, made of silica glass and fusion-spliced to the grating's fiber. The optical and the electronic setup of the sensor is given. The sensor was employed to measure pulse pressure generated by an electric discharge in water. The obtained measurement results and the conclusions arising from them are presented.

There is no method of direct measurement of amount coal dust supplied to the burner, as well as a primary air. It is important in avoiding flame instabilities that could lead flame extinguishing and thus, improve both safety and combustion quality. One of the quickest way of drawing information of a combustion process is to analyze its radiation. The article presents investigation of flame image features, that could point to a state of unstable combustion. Several combustion tests of pulverized coal have been done, generating stable and unstable state of combustion. In this article, some flame image parameters as image energy, entropy and median have been investigated as combustion quality pointers.

In the paper the concept of optical sensor FORS-II (Fiber-Optic Rotational Seismometer) application for detection of rotation effects occur during seismic events is presented. The main advantage of the FORS-II is its very high sensitivity in the range of about 2.10^-8 rad/s. Result of the system research and experimental data comparison with data obtain by two antiparallel pendulum seismometers are also presented. Finally, theoretical concept of observed rotation effects during seismic events is also presented.

The research presents the design and construction of a diffuser made of plastic fiber. The diffuser enables us to convey laser energy to the coronary vessels and allows their biostimulation. The project is a continuation of research on cellular biostimulation carried out at the Institute of Telecommunication, Teleinformatics and Acoustics, and Wroclaw Medical University Department of Cardiology.

This article presents construction and the measurement results for transmission and reflection sensors (in various configurations) using comb diaphragm, applied to displacement measurement.

This paper describes an application of curvelet transform analysis problem of interferometric images. Comparing to two-dimensional wavelet transform, curvelet transform has higher time-frequency resolution. This article includes numerical experiments, which were executed on random interferometric image. In the result of nonlinear approximations, curvelet transform obtains matrix with smaller number of coefficients than is guaranteed by wavelet transform. Additionally, denoising simulations show that curvelet could be a very good tool to remove noise from images.

The paper presents a modular fiber optic hydrostatic pressure sensing system based on a polarimetric highly birefringent photonic crystal fiber (HB PCF) operating at infrared wavelengths and utilizing a replaceable fiber-optic head, which allows simple fitting to the measured range of hydrostatic pressure. We propose also an all-fiber built-in analyzer that is based on polarization properties of the photonic crystal fiber filled with a liquid crystal. The output characteristics of the modular sensing system have been optimized in view of enhancing their measurement capabilities and in order to minimize disturbing environmental effects.

In the present work we demonstrate measurements obtained using optical fiber head sensors for high pressure composite vessel, composite strengthened concrete beam and the high-voltage composite insulator.

The article presents the influence of the length of fiber Bragg grating with linear changeable period on processing accuracy of impulsive excitations acting along the longitudinal fiber axis. Using transfer matrix method the power reflectivity spectrums caused by impulsive strains are obtained. On this basis, assuming that grating's output signal is of centroidal frequency, the mean square error was evaluated as a function of the ratio of the length of the grating to the length of impulse, for different shapes of impulsive strains.

In this article the proposals of the ways of modelling structures of fiber Bragg gratings by the use of the object-oriented programming and by the use of the direct and inverse problem were introduced. The results of the inverse problem solution, done for Bragg gratings, were also introduced in this work. This process was conducted by using of local optimization algorithms.

We present investigation results of a new generation of the fiber optic perimeter sensor in a Sagnac and Michelson interferometers configuration. This sensor can detect a potential intruder and determine its position along a protected zone. We propose a localization method that makes use of the inherent properties of both interferometers. After demodulation of signals from both interferometers, the obtained amplitude characteristic of the Sagnac interferometer depends on position of a disturbance along the interferometer, while amplitude characteristic of the Michelson interferometer do not depend on this position. So, quotient of both demodulated characteristics makes possible to localize the disturbance. Arrangement of a laboratory model of the sensor and its signal processing scheme is also presented. During research of the laboratory model of the sensor, it was possible to detect the position of the disturbance with resolution of about 40m along the 6-km long sensor.