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The paper presents the principle of operation, the structure, applications and methods of producing uniform, chirped and blazed fiber Bragg gratings as well as long period gratings. Finally, several selected methods used to make apodized gratings are listed and described.

Photonic crystals, the artificially created multilayer structures with dielectric permittivity and geometric dimensions varying with a period comparable to the wavelength, were studied by the calculation of light interference in a given multilayer system. The developed calculation programs using the matrix method made it possible to obtain the optical characteristics (reflection, transmission, etc.) for any multilayer coatings. The focus was on the analysis of the influence of defects associated with the violation of the layer periodicity. Spectral dependences of the reflection coefficient, argument of Chebyshev polynomial and argument module of the Chebyshev polynomial are given. The calculation of the optical characteristics of multilayer coatings by the matrix method provided the opportunity to identify the presence of barrier zones for periodic and defective systems and to propose their use as the contrast or narrowband interference filter.

The structural scheme of the hydropulse device for strain hardening of materials is considered. Based on the block diagram of the device, its complete and simplified dynamic models are developed. On the basis of the dynamic model of the device and the scientifically grounded structure of assumptions, a mathematical model of the device was developed, the hydraulic link in which is presented as the Kelvin - Voigt body. For energy reasons, the choice of the force of the shock interaction of the piston - pulsator with the surface of the processed part is grounded. For energy reasons, the choice of the force of the shock interaction of the piston - pulsator with the surface of the processed part is grounded.

Optoelectronic neuronal element on the n-type c-negatron is researched in paper. the offered neuron executes the main functions of neuron, such as spatial and temporal integration of optical (current) signals and has a threshold function of activating. theoretical basis of neuronal elements construction on the c-negatrons and computer simulations results of the neuron on the n-type c-negatron are shown in paper. advantages of the offered neuron element are schematic and technological simplicity, high speed, possibility of signal voltage amplification, low power consumption.

The spectral method of the jitter parameters estimation in fiber optics transmission systems is being suggested. The suggested method is featured with high accuracy at the expense of the statistical stability improvement of the results, obtained during the implementation of overlapping fast Fourier transform.

The aim of this work is the development of a reference source of subnanosecond pulses based on SiC breakdown LEDs. The micro-alloy technology of p-n junctions based on SiC-6H with a diameter of about 50 microns has been developed. The capacity of such structures does not exceed 10-20 pF. The high stability and current overload resistance of the samples were provided by the uniform microplasma breakdown structure. The breakdown electroluminescence spectrum of the investigated samples was flat and covered the range of 400-800 nm and the relaxation time did not exceed 0,25 ns (a time resolution of measuring system). The radiation power was about 10-6 W/A.

This paper outlines a measurement method of properties of microstructured optical fibers that are useful in sensing applications. Experimental studies of produced photonic-crystal fibers allow for a better understanding of the principles of energy coupling in photonic-crystal fibers. For that purpose, fibers with different filling factors and lattice constants were produced. The measurements demonstrated the influence of the fiber geometry on the coupling level of light between the cores. For a distance between the cores of 15 μm, a very low level (below 2%) of energy coupling was obtained. For a distance of 13 μm, the level of energy transfer to neighboring cores on the order of 2-4% was achieved for a filling factor of 0.29. The elimination of the energycoupling phenomenon between the cores was achieved by duplicating the filling factor of the fiber. The coupling level was as high as 22% in the case of fibers with a distance between the cores of 8.5 μm. Our results can be used for microstructured-fiber sensing applications and for transmission-channel switching in liquid-crystal multi-core photonic fibers.

This paper presents properties of all-optical bistable fibre switch using two fibre Bragg gratings and rare earth elements doped optical fiber. It is not possible to obtain bistable properties at low switching power level in case of a single fibre grating. In this article the method of optical switching that uses all-optical switch has been proposed. It has been achieved by varying the refractive index of nonlinear optical material as a result of light signal amplitude changes. Presented optical bistable device can be used both in contemporary optically switched networks as well as in optoelectronic sensors, owing to their high achievable resolution.

This paper presents the sensor characteristics of highly birefringent polymer side-hole optical fiber. The fiber core with greater refractive index was made of copolymer PMMA-PS, while the cladding of pure PMMA. The fabricated fiber showed relatively low losses of the order of 6 dB/m in the visible range. We measured several sensing characteristics in the fabricated fiber, including birefringence and polarimetric sensitivity to pressure and temperature. The fiber showed high polarimetric sensitivity to pressure, which is directly related to the presence of two large holes transferring symmetrical load applied to the cladding into nonsymmetric stress distribution in the core region. This in turn changes modal birefringence of the investigated fiber and increases the sensitivity to pressure.

Supercontinuum radiation in photonic crystal fibers (PCFs) has recently found exciting applications in metrology, fundamental research, and medical sciences. Intensive efforts have been put into optimizing supercontinuum radiation parameters such as spectral width, flatness, and brightness. This work presents results of supercontinuum generation in suspended core microstructured optical fibers. These results are compared with supercontinuum generation in photonic crystal fibers with hexagonal lattice.

We report on experimental studies of phase and group modal birefringence vs. temperature in two highly birefringent (HB) photonic crystal fibers, in which birefringence is caused by filling factor asymmetry. The sensitivity measurements were carried out at two wavelengths 633 and 834 nm. Our results show that temperature sensitivity in the HB photonic crystal fibers is two orders smaller then in traditional HB fibers. Simultaneously, our results exhibit weak dependence of group modal birefringence on temperature.

Paper presents technology and some characteristic of manufactured suspended core microstructured optical fibers with cores undoped and doped with germanium dioxide. Manufactured fiber is very useful for evanescent wave sensors. Additionally on internal layers of holes thin (thickness about 28nm) silver layers were deposited. Those optical fibers probably will be very useful for surface plasmon resonance sensors. We introduced 6nm thick silver layers into holes of ordinary photonic crystal fibers 1m long.

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.

Paper presents the state of advance of the silica glass microstr uctured optical fibers technology n Poland especially in Department of Optical Fibers Technology Maria Curie Sk aodowska 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. Keywords: microstructured optical fibers, birefringence, technology, silica glass, MCVD, OVD 1. INTRODUCTION The first photonic optical fibers wa s manufactured ten years ago [1]. Up t oday technology of this type optical fibers grow intensively both at an angle of attenuation decrease and in the direction of elaboration of new kinds of photonic fibers. The name photonic fibers change in to micros tructured fibers however the name microstructured fibers contain more kinds of optical fibers. For example high birefringent side hole optical fibers elaborated and first time manufactured ten years ago in Poland [2] not belong into photonic fibers group but they should be include into microstructured fibers group. In the first stage of technology growth photonic fibers was manufactured from non doped silica glass. The core and cladding was made from silica glass. In the next phase was appearance other materials: low-melting silica glasses, organic glasses nonsilica and nonoxygen glasses. Simultaneously was elaborated new fiber construction contain in structure some kinds of glasses for exam ple cladding made from silica glass and core made from silica glass doped with germanium (high silica glass). Now all construction materials for phot onic optical fibers may be divided into the same four groups as materials for the classic fibers [3]: silica glass (exactly high silica glasses), low-melting silica glasses, group of organic glasses mainly methyl polymethacrylate and recently cytop (polymer contain fluorine instead of hydrogen), group of nonsilica oxygen and nonoxygen glasses. Similarly as for classic optical fibers only photonic optical fibers from high silica glasses have small attenuation. Photonic optical fibers made from others materials have attenuations above 1000 times bigger, therefore their practical use are negligible. Hence major market offer concern only photonic optical fibers made from silica glass. However technology of manufacturing photonic optical fibers form silica glass is extremely difficult in comparison with technologies of manufacturing those fibers from different materials. It results from fact if ratio of surface tension of silica glass to it’s viscosity during fiber drawing is at least 10 times bigger than for other materials. Inconsequence requirement relative precision of technological processes in fiber manufacturing from silica glass is very high. Additionally silica glass temperature conversion in to optical fiber is equal 2000

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.

Optical fiber strain or bend sensors have been demonstrated for complex monitoring various structures especially in aerospace, marine civil engineering and especially in optical security systems. Optical fiber sensors based on Fabry-Perot interferometers and fiber Bragg gratings are useful for point or slow-multiplied sensor systems. Distributed optical fiber system based on Sagnac interferometers used of low or high-birefringence optical fibers as strain/bend sensing elements. Special optical fibers as four core single mode fibers in Mach-Zehnder interferometer system have been used. In all described cases the high influence of temperature on sensor characteristics is very important disadvantage at measurement systems. In this paper we describe fabrication and characterization of the new four core PCF index guided fiber designed for interferometric bend measurements.

The one of the manners of change or introduce birefringence of manufactured optical fibers is placed it into electric field. In accordance with description of Kerr effect the change of birefringence is proportional to the square of the electric field intensity. However the electric field intensity is proportional to the distance between electrodes. In standard optical fibers the change of birefringence through the Kerr effect required to use high voltage. In our laboratory the two new types of optical fibers were manufactured. One of them has structure similar to that of the side-hole optical fiber but the internal surface of the two open holes placed on the both sides of the core is covered with silver. It was named side metal pipe fiber (SMP). The other has four open holes placed symmetrically around the core. It is named single mode quadruple (SMK) optical fiber. The open holes with silver layers are placed a long distance from the core so as to they haven't influence on the light goes through the core. In those fibers the change of direction of polarization was measured. For the fiber with two holes the change was equal to 8 degree for the change of voltage equal to 500V. Paper presents basics of the technology of those fibers, description of the silver layers deposition process from liquid phase and geometrical and optical characteristics of fibers.

Technology and basic characterization of new kind of side hole optical fiber with silver layers in the holes named side metal pipe (SMP) optical fiber is presented. The static deposition method of silver layers of several hundred nm thickness from liquid phase was used. Polarization properties of the side metal pipe optical fibers were found.

The paper presents the technology of manufacturing dual core holey fibers and of measuring their basic sensor parameters. The measurements of the structural parameters, coupling length, Lc, temperature sensitivity, KT, pressure sensitivity, KP, was done from the angle of using this type of fiber in optical fiber sensors. The measurements were done for different directions of polarization of input light and for introducing light to one core and to two cores. It was found that the properties of the optical fiber depend on the conditions of light introduction. The results of these measurements were compared with analogous measurements for the high birefringence elliptical core optical fiber, high birefringence side-hole fiber, dual core optical fiber and high birefringence elliptical core holey fiber.

A new type special waveguides' production technology requires elaborating of a way of metals' introduction into the internal structure of the fibers. This study presents a way and an apparatus used for liquid phase silver layers' obtaining on the capillaries' inner surfaces, which are an integral part of waveguides, as a result of a redox process. The preliminary results of the research over silver layers' preparation reveal that the process is rather heterogeneous and the obtained layers of a few μm thickness and are porous.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The paper presents propagation properties of elliptical fibers with liquid crystal core under the influence of temperature, hydrostatic pressure and external electric field. Initial data on transmission losses of the liquid crystal fiber in the 0.5 - 2.0 μm spectral range is also presented. The scattering loss was found to be around 0,2 dB/cm for elliptical-core (4 x 18 μm) liquid crystal fibers that is in accordance with other measurements, whereas a significant increase to about 5 dB/cm was observed in liquid crystal capillaries.

We have manufactured and characterized a birefringent holey fiber of a new construction. The birefringence in this fiber is induced by the highly elliptical shape of the core, which consists of a triple defect in a hexagonal structure. Using a hybrid edge–nodal finite-element method, we calculated the spectral dependence of phase and group modal birefringence for spatial modes E11 and E21 in idealized and in real fiber, whose geometry we determined by using a scanning-electron microscope. Results of our calculations show that technological imperfections significantly affect the fiber's birefringence. Normalized cutoff wavelengths for higher-order modes relative to the filling factor were also determined for the idealized structure. We observed a significant disagreement between theoretical and experimental values of cutoff wavelengths, which was attributed to high confinement losses near the cutoff condition. We also measured the spectral dependence of the phase and the group modal birefringence for spatial modes E11 and E21. The measured parameters showed good agreement with the results of modeling.

We designed, manufactured and characterized two birefringent microstructured fibers that feature a 5-fold increase in polarimetric sensitivity to hydrostatic pressure compared to the earlier reported values for microstructured fibers. We demonstrate a good agreement between the finite element simulations and the experimental values for the polarimetric sensitivity to pressure and to temperature. The sensitivity to hydrostatic pressure has a negative sign and exceeds -43 rad/MPa x m at 1.55 mu m for both fibers. In combination with the very low sensitivity to temperature, this makes our fibers the candidates of choice for the development of microstructured fiber based hydrostatic pressure measurement systems. (C) 2010 Optical Society of America