Photonic crystals are known already, in some forms, for a longer time, but they become recently very popular and interesting for theoretical, numerical, experimental and application oriented research. The reasons for that are their very interesting properties exceeding characteristics and implementations limits of the traditional optical elements. Moreover in some cases they shift paradigms of optics. One of the very interesting examples of photonic crystals, intensively studied and investigated since 1990s, are photonic crystal fibers. In a brief way, the classification, few modeling approaches, unique properties, fabrication techniques, chances and threats for the potential applications are presented.

We present semi analytical, approximate model of nonlinear operation of planar waveguide laser manufactured on the base of 2D photonic crystal. We consider laser structure with F-P cavity and take into account the gain saturation effect, transverse as well as longitudinal field distribution. Our model, based on energy theory, allows to investigate in relatively easy way the influence of the real structure parameters such as photonic crystal geometry, waveguide geometry, losses as well as strength of feedback (i.e. cavity parameters) on output power level. The laser characteristics obtained reveal optimal feedback strength for given laser structure, which provide maximal power efficiency for given pumping level.

We present an analysis of above threshold laser generation in F-P laser having 1D Photonic Crystal active medium. Our approach is based on matrix approach including gain saturation effect.

A square lattice photonic crystal fiber is described. The square lattice structures were fabricated, characterized and their polarization properties were investigated. The polarization properties of the fibers were not as strong as those reported previously in highly birefringent PCF, but these structures have considerable potential for high birefringence.

The structure of an electro-optical modulator is proposed which permits to overcome the limitations imposed by the parameters of control channel. The basic components of the modulator are electrically controlled fiber Bragg gratings. The proposed structure makes possible to obtain the modulation of optical radiation with double frequency compared to other modulators with the same electronic control circuits. In the paper we calculate the modulation characteristics of such modulator, consider the different conditions of it operating and estimate the possibility of farther increasing the speed of modulation by optimization of the parameters of fiber Bragg gratings. The proposed device is compact and well interfaced with optical fiber links.

The interferometric techniques of realization of fiber Bragg gratings are presented. The practically performed laboratory optical system is described. First results of Bragg gratings written by this method on hydrogenated standard telecom fibers are given.

Wideband (L, C, S) light source for the third fiber transmission window was developed. It has replaced incandescent halogen lamp light source in grating monochromator to increase the input signal level during measurements. This replacement has resulted in measurement time decrease and dynamic range increase in narrowband FBG spectral measurements. The source is an offer for other fiber metrology equipment users.

A fiber Bragg grating is a very attractive passive device widely used in telecommunication networks, laser technologies, metrology and research laboratories. The Institute of Electronics Systems has recently opened the new laboratory for writing Bragg gratings directly on fiber cores. The application of a phase mask is a reasonably simple technique for material, fiber photosensitivity research and filter spectral characteristics control.

In the paper the results of simulation and experimental investigation are presented of an optical frequency discriminator with an apodized, fiber Bragg grating of a constant period, cooperating with an identical grating of the sensor. Assuming the nonlinearity of the discriminator's conversion characteristic not greater than 1%, a conversion range of 0.30 nm was achieved, for gratings with a 3 dB bandwidth of 0.45 nm. Discriminators of such a type can be useful in many problems of dynamic measurements of mechanical quantities. Their certain inconvenience is the necessity of using an optical circulator, which is more expensive than a fiber optic coupler.

We apply the fully vectorial plane wave method to calculate birefringence in photonic crystal fibers with circular and elliptical holes. Holey fibers provide the possibility of reaching extremely high modal birefringence retaining single mode guidance at the same time. Such Hi-Bi holey fibers are naturally of particular interest for sensing applications. From the technological side it is important to know which types of fiber profiles lead to the high values of modal birefringence, and the present contribution includes a comparison of selected fiber microstructures with elliptical air holes from the point of view of attainable birefringence.

Holey fibers (HF) as a subgroup of photonic crystal fibers (PCF) constitute a new class of optical fibers which has revealed many interesting phenomena paving the way for a large number of novel applications either in the telecom or in the sensing domain. However, some of the applications require the use of specialty fibers with a doped core. A numerical investigation of fundamental and higher order modes propagating in doped core birefringent holey fiber is presented. The conditions for the co-existence of two competing light guiding mechanisms, their consequences on the mode propagation and the potentialities for novel applications are discussed.

Polarization maintaining photonic crystal fibers constitute a new class of birefringent optical fibers with strong separation of polarization modes and large possibilities of tailoring different parameters. These advantages appear to be perfect for designing optical fiber sensor, so we decided to test this type of fiber. A plane-wave method was used to numerically calculate the effective refractive indices and the field distribution of the propagation modes. The simulation results were compared with experimental measurements of the birefringence and finally the fiber was experienced as a sensor with fully automated set-up. The verification of temperature sensitivity simulations was performed too.

Most works on photonic crystal fibers used for telecommunication are concerned with the structure of single mode fibers with a hexagonal lattice. However, there are many other possible choices of the fiber's crystal structure. In this paper we present a comparison of the basic characteristics of the photonic crystal fibers with hexagonal and rectangular crystal lattices and of the resulting differences in the structure's axial symmetries. Like in natural crystals the number of the axes of symmetry implies different optical characteristics of the photonic structures. In order to compare the properties of the photonic fibers with a hexagonal and rectangular lattices we use a vector method of biorthonormal bases. We also present a possible technology of manufacturing fibers with different crystal structures.

The freedom in choosing a crystal structure of the photonic fiber makes possible to manufacture fibers with more than one core. In this paper we present simulations of the characteristics of a double-core photonic crystal fiber with a square lattice. Such fiber can be used in telecomunication switches. The simulations of the modal structure were done using a vector method of biorthonormal bases. The results show that a double-core crystal, which exhibits mode coupling between cores fiber, can be designed. We present preliminary results of manufacturing of a double-core photonic fiber and measurements of its transmission characteristics.

We present the results of modeling of photonic crystal fibers with a square lattice and square holes. In photonic fibers having an order m = 2 symmetry the degeneracy of the fundamental mode that is a combination of the polarization modes HE₁₁^x and HE₁₁^y disappears. The advantage of the square structure is that the photonic crystal fiber becomes very sensitive to deformations caused by external factors yet it remains highly birefringent. The propagation constants of both modes were calculated using the vector method of biorthonormal bases. The use of a square lattice in a photonic crystal fiber makes possible to achieve birefringence of the order of 10^-2. We have examined the dependence of birefringence on the geometrical parameters of the fiber's structure.

Liquid crystal circular core optical fibers cannot have a stable structure of arrangement because of misfit of core geometry and properties of liquid crystals. Fibers of high ellipticity of core are much better in this case but controlling the state and degree of arrangement of a liquid crystal by external electric field requires application of high voltage. The work presents the technology of substrate of liquid crystal core fibers in the form of quartz glass capillaries with highly elliptic central hole and two additional holes placed at both sides of the central one along the fiber. On the surface of side holes layers of nickel were deposited by thermal decomposition of nickel carbonyl from a gaseous phase. Substrates 2 m long with dimensions of central hole 4 x 18 μm were obtained and characterized. The produced substrates may allow preparation of a new generation of liquid crystal core fibers. The work also presents the design of laboratory scale apparatus for preparation of a new generation of liquid crystal core fibers. The work also presents the design of laboratory scale apparatus for preparation of nickel carbonyl as well as conditions of its synthesis.

Basic structures of silica photonic fibers with triangular lattice made from a single prapreform are presented. Variation of the filling factor was achieved by adjustment of fiber preparation conditions. Fundamental structural and transmission parameters were measured for a chosen fiber. A problem of searching of procedures for further decrease in attenuation of fabricated fibers was formulated on the base of obtained results.

Erbium doped fiber is a basic element of an optical amplifier. The estimation of fiber parameters set is the main problem of designing its application. The knowledge of fiber core radius, the overlap factors representing the fraction of pump power and signal within the doped region, doping concentration and fiber glass type are necessary for this task. The problem is significant, because fiber producers do not print full data or the printed data do not agree with facts. The presented solution is their identification with typical printed and measured data using in mathematical model of quantum and wave optics. The elaborated method was tried on 3M active fiber samples, effects show that its correctness is about 15%.

Signal amplification and noises in active fibers can be investigated both mathematically and experimentally. The investigation is connected with construction of appropriate models. The presented work is referring to the description and analysis of light intensity nature phenomenon appearing during optical signal amplification in optically pumped fibers. The mathematical model that describes the optical pumping and laser action phenomenon that occurs in unit fiber section length is called the energy level diagram. In case when the fiber is the erbium doped energy model is often represented as three level scheme that sometimes is simplified to two levels. Introducing openly the fiber length results in the equation set of radiation intensity propagation. In the physical model real components, which are examined, are applied. In this work in order to build the physical models of amplifier the following components were used: active fiber from 3M corporation, optical pump working at 980 nm from Power Technology, laser signal source for 1550 nm from Thorlabs and optical isolators, WDM-s and connectors. This opto-electronic circuit has been monitored using the computer system by set of Si and AlGaAs detectors. The results obtained by the authors show that simple models of signal amplification can be used, but at the same time the optical noise phenomena are much more complex and have significant broad band value. Their power at output of fiber amplifier, even working on standard operation point, can saturate the photo detector.

The paper presents investigation results for fiber lasers built on the basis of polarization maintaining erbium-doped fibers. The multiwavelength operation of a laser was presented in the setup of a ring fiber laser. By changing the polarization state of the signal and the pump by means of polarization controllers built into the ring resonator multiwavelength and singlewavelength laser operation was obtained.

A method of pumping lasers built on the basis of double-clad neodymium-ion doped fibers is presented in the paper. Couplings were realized by asymmetrical couplers built with a multimode PCS (pumping) fiber and a double-clad (pumped) fiber. Special software for designing such asymmetrical couplers was elaborated. It allows us to choose appropriate parameters of the coupler's components, enabling to obtain a maximum pumping power, introduced by the purpose-built coupler.

In this work we presented some selected techniques for all optical gain control of EDFA. Special attention was devoted to the comparison of linear and ring laser configurations of all optical methods of amplifier stabilization. We showed numerical and experimental results of gain clamped amplifiers with ring lasers.

This paper presents the experimental investigations in the fabrication of the double-clad optical fibers doped with ytterbium with the optimal cross-section of the first cladding. Those investigations were done on the basis of the optimization of the first cladding cross-section shapes in optical fibers doped by neodymium. The fabricated optical fibers doped by ytterbium were characterized by the measured spectral attenuation and by giving their so-called geometrical and real active cross-section.

The source of ASE around 1550 nm based on double clad erbium-ytterbium doped fiber is presented. Such source can be much cheaper alternative comparing to tuneable semiconductor lasers.

Determination of planar waveguide parameters with a deposited thin layer such as a refractive index and thickness by the method of m-line spectroscopy is possible. Application of the method to determination of thin film parameters of anisotropy material has been presented in this paper. Depositing of a very small quantity of the material on the planar waveguide changes propagation depending on a texture of a crystal. Liquid crystal (LC) is typical material characterizing the texture. Optical parameters of anisotropic materials (LC) have been determined by the modified m-line spectroscopy in four-layer waveguide structures. Preliminary investigation of application of this method to the study of anisotropic materials has been confirmed.

The paper presents technology of 1xN waveguide splitters based on multimode interference (MMI) structures made by ion exchange in glass. A method of modal field interference examination in MMI structures, using fluorescence of the substance covering the MMI section is proposed. Testing investigations are carried out for MMI structures made by K⁺↔Na⁺ ion exchange process in glass. Studies of technology of 1xN waveguide splitters based on MMI structures made by ion exchange in glass are also presented.

The work is related to the design of vibration sensor's head represented by MOEMS structure. The head consists of two optical fibers and micro beam that lays between them. The principle of operation of the head is free space light modulation by micro beam. The elaborated head model enables analysis of influence of head and stimulation parameters on measured output light. The main parameters of the head are material used for micro beam fabrication and beam dimensions. The micro beam can be fabricated monolithically or as added component so it can be made from silicon or glass. The micro beam types qualify the sensor type as amplitude or frequency transformer. These head types require different types of detection block. What is interesting, technologically simpler frequency transformer requires more complex detection device than amplitude transformer.

Problem of efficient light coupling into planar waveguide structures was always a stumbling block for the designers of integrated optical circuits. In this article methods of light coupling into the planar waveguides are described. Comparison of two main approaches -- prism and grating coupling -- is given. Examples of grating coupler technology are presented also.

The surface plasmon resonance spectroscopy is an optical technique that is capable of monitoring chemical and physical processes. It is sensitive to detect small changes of dielectric properties in a metal-phthalocyanine boundary. For this reason plasmon resonance phenomena have been used to characterize a number of different types of films. This work analyses the possibility of using the surface plasmon resonance phenomena in the detection of gas. Thin films of copper and lead phthalocyanines have been examined in the plasmon system from the point of view of their application in NO₂ sensors.

In the paper propagation of stationary hybrid TE-TM electromagnetic fields through nonlinearly anisotropic Kerr layer is considered. For arbitrary phase shift between TE and TM components the permittivity tensor describing different mechanisms of nonlinearity is obtained. The system of Maxwell's equations, nonlinear material equations and boundary conditions are solved numerically in the three-layered structure. For the weak field approximation the analytical expressions approximating fields of nonlinear fundamental mode and its power are derived.

The paper presents the results of investigations involving the influence of drying time and annealing temperature on refractive index and thickness of two-component dielectric layers SiO₂:TiO₂ produced with the application of sol-gel technology. The production technology and the method for the determination of parameters of the produced layers has been discussed. The results of theoretical analysis of planar refractometer has been presented in the system of difference interferometer produced with the application of the elaborated planar waveguides.

The paper presents the theoretical and experimental results involving the influence of refractive index profile on the interaction of modes with the absorption sensitive film. The attenuation distribution of modes in planar waveguides with absorption cover depends on the shape of refractive index profile. In particular, the character of this distribution depends on the location of turning points of particular modes. In the structures with gradient refractive index profiles, the dependence of modes attenuation on their order can be a non-monotonic function.

The paper presents the results of investigation involving the influence of the change of launching conditions on the characteristics of amplitude ammonia sensors produced with the application of strip waveguides of different refractive profiles. Strip waveguides were produced using ion exchange technique, and the absorption sensitive films were produced using sol-gel technology.

The paper presents a layered sensing structure that permits to detect and to measure the concentration of hydrogen in a gaseous medium. This metal-dielectric-metal structure is a layered Fabry-Perot interferometer. The resonant cavity is made of WO₃. The choice of just this material was dictated by its chemochromatic properties, i.e. the change of the optical properties due to the absorption of atomic hydrogen. In result of the absorption of H⁺ and e^- the purely dielectric layer becomes a lost layer, displaying attenuation. The catalysis of molecular hydrogen to atomic hydrogen occurs in the palladium layer, which is also one of the mirrors of the interferometer. The measurement of the hydrogen concentration consists in the scanning of the angular variation of the interference peak position due to the absorption of hydrogen. The change of the peak position results from the change of the optical parameters of the Pd and WO₃ layers.

The paper presents a way of determining the fundamental parameters of the design of a hydrogen sensor, the operation of which is based on the phenomenon of the resonance of surface plasmons (SPR - Surface Plasmon Resonance) in Kretschmann-Raether's system. The designed system has been realized. Its investigation results have also been presented.

The paper presents the results and way of measuring the dispersion of the complex refractive index of thin palladium layers in an atmosphere containing hydrogen with a concentration below the threshold of explosion (<4%). The measurements were carried out making use of exciting the surface plasmon wave.

In the work the results of investigations of birefringence arise in glass BK-7 in long-lasting processes of diffusion of ions K⁺ from liquid source of admixture KNO₃ in temperature ~400°C -- in range of times 24÷504 h has been presented.

The paper presents the results of investigations demonstrative possibility of formation refractive index profiles of planar waveguide produced by technique of ion's exchange in glass substrate in electrodiffusion processes with the changes of the direction of electric field polarization.

The number of polymer fibers' applications grows rapidly now days. The polymer fibers are characterized with a large core diameter, large numerical aperture, large losses and large elasticity. The consequence of large elasticity is possibility of fiber putting down in skirting-board. The skirting-board width is down to 1 cm, and its path has many corners that mean that fiber has many bends with curvature radius about 1 cm. The power losses in fiber bend can be estimated on fiber core radius to curvature radius ratio. Therefore, this type of optical signal losses is greater in polymer fiber paths than in glass ones. This paper presents the new method of mathematical modeling of optical losses in real polymer fiber transmission lines. The experiment shows that in standard polymer fiber lay down the geometrical and material optical losses have similar values. The elaborated method is correct.

Presented work concerns designing and making the asymmetric couplers. Three-dimensional fiber space modeling of light propagation have been used in the project. Couplers were made using two different technologies of gluing. Design results are confirmed by experiments and elements have expected parameters.

Basic properties of thermoplastic optical fibers are described. Resulting possibilities and limitations of polymer fiber use in optical sensors are discussed. As an example the idea of the integrated alarm system head, containing smoke, temperature and humidity sensors, is shown.

The article presents the results of examinations concerning distribution of the luminous flux in the end-light lighting optical fibers, in which the end-surface was subject to deliberate shaping. A method for shaping the distribution of the luminous flux in lighting optical fibers was designed, devoid of using sockets and any additional heads shaping luminous intensity distribution.

The basic advantage of illuminating plastic optical fibers is related to simplicity of their processing. Thanks to such characteristic, it is possible to create optical fiber bundles, which fit exactly the given illumination solution. Two basic methods of procesing optical fibers are most common: grinding and polishing or thermo-cutting with the means of so-called "hot knife." These two types of processing were then examined against their influence on the luminous parameters: amount of the transferred luminous flux and the shape of the luminous intensity distribution.

Development of Polycrystalline Infrared (PIR-) fibers extruded from solid solutions of AgCl/AgBr has opened a new horizon of molecular spectroscopy applications in 4 - 18 micron range of spectra. PIR-fiber cables and probes could be coupled with a variety of Fourier Transform Infrared (FTIR) spectrometer and Tunable Diode Lasers (TDL), including pig tailing of Mercury Cadmium Tellurium (MCT) detectors. Using these techniques no sample preparation is necessary for PIR-fiber probes to measure reflection and absorption spectra, in situ, in vivo, in real time and even multiplexed. Such PIR-fiber probes have been used for evanescent absorption spectroscopy of malignant tissue and skin surface diagnostics in-vivo, glucose detection in blood as well as crude oil composition analysis, for organic pollution and nuclear waste monitoring. A review of various PIR-fiber applications in medicine, industry and environment control is presented. The synergy of PIR-fibers flexibility with a super high spectral resolution of TDL spectrometers with Δν=10^-4cm^-1, provides the unique tool for gas analysis, specifically when PIR-fibers are coupled as pigtails with MCT-detectors and Pb-salt lasers. Design of multichannel PIR-fiber tailed TDL spectrometer could be used as a portable device for multispectral gas analysis at 1 ppb level of detectivity for various applications in medicine and biotechnology.

The bulk acoustooptic Bragg modulator shifting light frequency at 105MHz, adapted at the 1550 nm bandpass and coupled into single-mode telecommunication fiber is presented. It was used in the experiment of self-heterodyning measurements of semiconductor lasers spectral linewidth.

In this paper, a review is given on the principles of optical fiber Bragg grating (FBG) sensors and their applications a strain sensors. Since the discovery of photosensitivity in optical fibers there has been great interest in the fabrication of Fiber Bragg Gratings within the core of a fiber. The ability to inscribe Bragg gratings in these photosensitive fibers has revolutionized the field of optical fiber based sensor technology. This work reviews the achievements about the FBG as a strain sensor and describes the potential applications of these sensors. The present paper discusses some of the parameters of gratings, which are important for sensor's constructions. These sensors are constructed on the basis of elasto-optic effects where the deformation is coded in wavelength.

In this article initial works to the point of examination of Fiber Bragg Grating (FBG) sensors are presented. We describe this works in the context of use FBG elements in construction of temperature sensors. We have compared theoretical assumptions and studies with practical results, which had been received in first lab examinations.

The visualization and analysis methods for studying vibration modes of macro and micro scale objects with spectrally reflecting and scattering surfaces, developed at the Institute of Micromechanics and Photonics of the Warsaw University of Technology, are presented. Silicon technology prepared microspecimens (AFM cantilevers and active PZT micromembranes) are investigated using two-beam time-average interferometry. Vibration modes of flat and non-flat surface microelements are displayed using four and five-frame temporal phase stepping methods. The calculated contrast of vibrating object interferograms provides the information on the vibration amplitude. Scattering surface objects are studied by time-average fiber-optics digital speckle pattern interferometer (DSPI) with heterodyning. Sinusoidal phase modulation introduced at the object vibration frequency enables quantitative analysis of the amplitude and phase of sinusoidal type vibrations. Laser diode modulation and/or single mode fiber stretching is applied for that purpose. For low vibration amplitudes (a₀ < l/20) the method using linear approximation of the zero order Bessel function provides an automatic analysis tool for quantitative estimation of the vibration modes.

The paper presents a research project oriented towards development of existing measurement methods which use optical sensors for the research and diagnostics of the combustion process in the internal-combustion automotive enigne. Experiments assume usage of photometric techniques and in particular spectrophotometry of the flames existing in the combustion chamber. Gathered results will enable expanding knowledge about processes taking place during combustion of air-fuel mixture and accompanying phenomena (i.e. knock, misfires). The work is also aimed at designing a diagnostic system which will enable an on-line identification of unfavorable phenomena like knocking combustion or misfires (lack of combustion). Extracted synthetic quality indexes will be used in the improvement of combustion process and as a feedback signals in the engine control algorithms. Research is made on the typical automotive engine equipped with an optical sensor located in the engine head and having direct access into the combustion chamber. The sensor enables on-line transmission of the optical signal during the combustion through the bundle of optical waveguides and two parallel filtering paths. Then optical signal was filtered with set of interference filters. The paper is illustrated with some results obtained during preliminary experiments.

Construction of fiberoptic humidity sensor based on active layer of CoCl₂ is presented in the paper. Processing characteristics were measured as well as its dynamic properties.

In the paper the results of investigation of luminescence properties of the coumarine derivative used as an optical UV/VIS transducer in the optical fiber UV sensor are presented. It was found that this compound probably chemically reacts with the polymer matrix in which was dissolved. The arising compound reveals luminescence properties other than initial coumarin derivative and is highly photostable.

Optical and optoelectronics technologies are more and more widely used in the biggest world experiments of high energy and nuclear physics, as well as in the astronomy. The paper is a kind of a broad digest describing the usage of optoelectronics is such experiments and information about some of the involved teams. The described experiments include: TESLA linear accelerator and FEL, Compact Muon Solenoid at LHC and recently started π-of-the-sky global gamma ray bursts (with asociated optical flashes) observation experiment. Optoelectornics and photonics offer several key features which are either extending the technical parameters of existing solutions or adding quite new practical application possibilities. Some of these favorable features of photonic systems are: high selectivity of optical sensors, immunity to some kinds of noise processes, extremely broad bandwidth exchangeable for either terabit rate transmission or ultrashort pulse generation, parallel image processing capability, etc. The following groups of photonic components and systems were described: (1) discrete components applications like: LED, PD, LD, CCD and CMOS cameras, active optical crystals and optical fibers in radiation dosimetry, astronomical image processing and for building of more complex photonic systems; (2) optical fiber networks serving as very stable phase distribution, clock signal distribution, distributed dosimeters, distributed gigabit transmission for control, diagnostics and data acquisition/processing; (3) fast and stable coherent femtosecond laser systems with active optical components for electro-optical sampling and photocathode excitation in the RF electron gun for linac; The parameters of some of these systems were quoted and discussed. A number of the debated solutions seems to be competitive against the classical ones. Several future fields seem to emerge involving direct coupling between the ultrafast photonic and the VLSI FPGA based technologies.

One of many hazards in industry is presence of airborne dust. Recently, we have proposed a "dust measuring sensor," operating on light scattering effect and constructed in space-optics technique. Tests of the device performed in normal operating conditions in a coal mine underground showed it worked properly and met requirements of that application except of zero-drift stability. The unsolved problem was dirtying of optical elements of the device during work by dust. Operating conditions of such a device are cruel -- humidity, elevated temperature, vibrations, and over-all contact with dust are harmful for optics. Thus, achieving reliable indications of the sensor is really a challenge. In the present work we test the idea to solve this problem by replacing bulk optics in the sensing area by optical fibers. First laboratory examination and operational tests of the fiber-optic sensor are also reported.

Two constructions of microfluidic structures are described in this paper. A fiber optic chemical coupler and a microcell for spectrophotometric measurements were designed and tested. The structures were made of polymer optical fibers (PMMA) which were incorporated into polymeric material i.e. poly(dimethylsiloxane). The structures were tested as detectors in refractometric experiment (saccharose solutions with different concentrations were used), in absorbance measurement (solutions of a bromothymol blue with different pH were used) and in fluorescence tests (solution of erythrosine was used).

The theoretical analysis of sensitivity of the Sagnac interferometer-based sensor is presented. This setup has wide range of implementation -- one of them is a perimeter sensor for security systems. Sensor sensitivity is determined firstly by a frequency-phase sensitivity, which is connected with the interferometer principle of operation and, secondly, by electronic noise of a processing unit and attenuation of used fiber optic.

Theoretical description of a contrast in an unbalanced fiber optic Michelson's interferometer with a multimode laser was shown. Periodic contrast oscillations, which depend on a laser spectrum, occur if a measuring arm of the interferometer is elongated. Required characteristic features of the contrast for an elongation sensor were determined. Influences of laser spectrum parameters (wavelength, halfwidth and mode spacing) as well as laser mode amplitudes on the contrast were simulated. Optimal spectrum for the dislocation sensor was determined theoretically. A laser which parameters fulfilled the requirements was found and its spectrum was measured. The measured contrast function was very similar to the optimal theoretical plot what proves correctness of the calculations.

Investigations of autofluorescence of cancerous tissues are used in clinical diagnostics. They are only estimative and allow us to define with close approximation the area of cancerously changed tissue. The paper presents a digital analysis of autofluorescent images. The analysis was conducted in the Matlab software environment. Pictures in the RGB range of colors were processed, obtained in similar lighting conditions exciting autofluorescence. As the result of digital processing distributions of intensity were obtained for three basic colors (red, green and blue). The intensity distributions of green and red were shown in three-dimensional space, where the points of the tissue examined were identified on the x y plane, and the intensity bound up with a given color was depicted in the third dimension. On the basis of results obtained this way the intensity ratio of green to red was defined in a selected spot in the examined tissue, and on this basis an attempt at assessing the advancement of cancer was made.

A fiber-optic sensor system, based on interferometric fiber-optic pressure sensor has been developed to measure cylinder pressure for closed-loop process control. The pressure-need sensors for improved for reciprocating in-cylinder engines is widely recognized. The ideal sensor would give accurate readings of combustion chamber gas pressure with high temporal resolution within each engine cycle. Engine control systems incorporating these sensors could reduce harmful emissions levels and improve fuel economy, as well as perform parametric monitoring for predicting emission levels. In the paper the interferometric fiber-optic pressure sensor was descripted. Measurements on a gasoline-fueled engine were reported.

A novel design of an interferometric hydrophone transducer is presented. It consists of a coil of fiber embedded in a layer of epoxy. Finite Element modeling of such transducer is difficult due to anisotropic mechanical properties of its structure. An approach based on laminate modeling techniques was adopted. Static and modal Finite Element analysis was conducted, as was a coupled-field acousto-mechanical analysis.

A novel design of an underwater acoustical pressure transducer based on a Fiber Bragg Grating is presented. In this transducer the sensing grating is writen in a rare-earth doped fiber and operates as an optically pumped Distributed Feedback (DFB) laser. Presented sensor has higher resolution, compared to a sensor using a passive Fiber Bragg Grating. A profiled membrane is used in the transducer to achieve equalization of stress acting on the grating along its length. Results of Finite Element modeling of the transducer are presented.

The use of Single Mode Polarization-Maintaining Side-Hole (SMPM-SH) fibers for direct measurement of transverse force has been studied theoretically and experimentally. Based on results of Finite Element modeling reported elsewhere it was known that certain SMPM-SH fibers exhibit higher sensitivity to transverse force than a standard SMPM fiber. In order to verify these predictions, an experiment was performed. Measurement results agreed well with theoretical predictions. However, more systematic research is needed to determine the relationship between the sensitivity, dimensions and geometry of the holes.

The paper discusses influence of longitudinal strain on polarization mode dispersion in highly birefringence fibers. It appeared that polarization mode dispersion could be diminished owing to longitudinal strain. The compensating configuration based on dynamically induced longitudinal strain in the HB bow-tie fiber was proposed.

This paper presents review of optical radiation measurement method in combustion process. Analysis and comparison of different methods is described and some applications in coal combustion boilers are shown. Such sensors can detect presence of target molecule, measure concentration ratio of two molecules and quantitatively measure the concentration.

In this paper we present initial analysis of time series obtained from fiber optic monitoring system. The results indicate that application of GA (Genetic Algorithm) for control of nitrogen oxides (NOx) emission from power burner brings promising results and perspectives for development of fiber optic sensors for combustion quality evaluation.

The flame monitoring system is intended to use in industrial condition for controlling pulverized coal combustion in power boiler. Placing the fiber-optic probes close to the each burner, one can obtain detailed information of the coal combustion process within the single burner. In order to enhance flame-monitoring system sensitivity for detection of fuel's composition changes, we have measured flame emission spectra.

Burning pulverized coal in power boilers causes considerable emission of atmospheric pollution. In order to decrease it the combustion process itself has been modified, however at cost of side effects like: increased level of unburned coal particles in the ashes. There are tens of burners in a single power boiler and emission level measurements are made in flue gas duct, so the control based on such averaged and heavily delayed values often results ineffective. The neural controller of the pulverized coal burner attempts to resolve these problems. The clue is utilization of fiber-optic system for monitoring of chosen zone of flame developed in Department of Electronics of Technical University of Lublin. The article contains description of controlled system and optical fiber measurement system, an idea of the controller as well as some results obtained for experimental burner.

Operation of combustion process in power boilers in such a way that pollution standards are met and corrosion is limited requires continuous measurement of concentration of selected gases in the near wall layer of power boilers. The absorption spectroscopy is one of methods that allow such measurement. Specificity of the medium in which the measurement is to be made (among other things: high temperature, difficulties in installation of sources and detectors) requires utilization of optical fiber technology. Absorption spectra overlapping in the medium infrared range is an additional hindrance which makes application of special measurement algorithms necessary. A concept of structure of optoelectronic analyzer of CO concentration in the near wall layer of power boilers has been presented. The analyzer is based on modified correlation absorption spectroscopy within the range between 1557 nm and 1600 nm. Simulation results have been presented as well.

A method of measuring the illuminance distribution in the focus of the optical fiber illuminator is presented in this paper. The mentioned method makes use of the polymer-quartz optical fiber, type F-PCS-600/900-US. The fiber's front surface was moved on the examined surface in two, mutually perpendicular directions. The luminous flux, exiting the optical fiber was then measured with the use of the integrating sphere. An exemplary illuminance distribution was also presented in the paper. Illuminance curves were then compared for PCS and plastic optical fibers made from methyl polymethacrylate.

In this paper we consider blocking probability for optical AON networks. It is assumed that call requests arrive at a node according to a random, Gaussian point process, and an optical circuit is established between the source and destination for the (random) duration of the call. It is necessary to consider two possible network structures here: nodes with no wavelength conversion capability and nodes that can convert an incoming wavelength to an arbitrary outgoing wavelength.

Methods of determination of coordinates of the center of a narrow radiation beam by means of the CCD array are considered. For the continuous representation of images and noises the analytical expressions describing signal and noise functions at the output of optimal spatial filter are obtained, as well as the dispersion of optimal estimation of a position of Gaussian radiation beam. It is shown that using the CCD array the minimum error of estimation of the Gaussian beam position is observed when the beam effective diameter is approximately equal to 0.8 of lateral length of a light-sensitive cell of the array.

In the paper the results of numerical analysis are presented of ultrashort pulse propagation in a highly birefringent optical fiber for a Gaussian initial pulse. It is assumed that the initial pulse is polarized linearly and guided into the fiber at an angle of 45° to its polarization axes. The analysis was carried out by numerically solving a pair of coupled Nonlinear Schrodinger Equations using the Split Step Fourier Method. The calculations were performed for an optical fiber without attenuation.

Generation of fundamental soliton in nonlinear optical fiber from chirped pulses of different initial shapes will be discussed. Results of numerical calculations having in view solution of Nonlinear Schrodinger Equation for complex initial condition using Split-Step Fourier Method will be presented. Initial shape-dependent critical value of the chirp parameter will be determined. Critical value is such a value of the chirp parameter at which generation of soliton in optical fiber is impossible.

Optoelectronics synthesizes many ideas -- classical and quantum electronics, physics of semiconductors, integrated electronics etc. Studying optoelectronics requires good preparation in appropriate disciplines. On the other hand courses in optoelectronics form a part of many other curricula. The article shows the role optoelectronics within a framework of classical university education as well as of authors' experience and ideas in teaching optoelectronics at the Belarussian State University.

A transition to multilevel system of preparation of specialists at Belarussian State University required educational process system reorganization. It supposed rebuilding all the curricula, but also was used for methodical improvements. The process is stil in progress and authors describe their experience in management of teaching of semiconductor quantum electronics in the transition period.

The paper presents a specially constructed device for coupling semiconductor lasers with optical fibers. The high-tech device controlled by stepper motors and specially elaborated software enabled us to position the fiber in three axes with the precision of one micrometer. The presented setup was tested for different couplings -- laser sources and fibers. Very good results were obtained both in coupling semiconductor sources and helium-neon lasers with multi- and single-mode fibers.

One of the available means for directing luminous flux in luminaries with light guiding plates is depositing diffusive elements of Lambertian characteristics onto the side surfaces of such a plate. A theoretical method of determining light intensity distribution of such elements, as well as resulting measurements for the model set, are presented in the paper. Additionally, a degree of light polarization in such a system was measured and analysed.

Light guiding plates coupled with fluorescent lamp are modern solutions in construction of general-purpose luminaries. Thanks to such a solution, large illuminating surfaces are created, characterized by constant luminance. Providing that the total height of such a device is relatively small, fluorescent lamps with high luminous efficacy might be used successfully. The problem related to the influence of the fluorescent lamp light color on attenuation of the luminous flux in the light guiding plates is relatively seldom approached. Theoretical calculations of the absorption index are presented in the paper, along with their verification against exemplary light guiding plates made from methyl polymethacrylate and type T5 fluorescent lamps with varying light color.

In the article we present the idea of the data preprocessing in the optoelectronic measurement system for monitoring the industrial gas pollutants. A single optical measurement path can carry big amount of data in entirely parallel manner (e.g. spectral response of light in an absorbing media). To meet the requirements coming from optical system properties, the new algorithm called Local Discriminant Basis with Feature Selection -- LDBFS is proposed. It based on discrete wavelet transform and multidimensional data decomposition techniques. In order to assess the performance of the proposed method, the article presents the simulation results of data analysis of gas spectral absorption.

In this work an analysis of one-way and two-way reflectometric measurements of splices of single mode fibers with different parameters has been made. Results of splicing conditions optimization for standard fibers MC SMF (Matched Cladding Single Mode Fiber - G.652), and with non-zero dispersion NZDS SMF (Non-Zero Dispersion Shifted Single Mode Fiber - G.655) have been presented. On the basis of one-way reflectometric measurements a method explicitly proving the existence of a transient area in the spliced fibers has been presented. Reference to norms and recommendations concerning one-way and two-way reflectometric measurements of telecommunication fibers splices have also been made.

In the paper simple genetic algorithm (SGA) as well as its modifications were applied for optimization of an optical fiber UV sensor construction. Influence of the algorithm parameters i.e. the population size, the probability of crossover and mutation from the point of view of algorithm efficiency is discussed herein.