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1
Content available remote

Polarization in Optical Fibers

100%
Woliński T.
Acta Physica Polonica A
|
1999
|
vol. 95
|
issue 5
749-760
EN
Physical origin of polarization phenomena in highly birefringent optical fibers including nonlinear optical effects is discussed and their impact on applications to polarimetric optical fibers sensors is underlined.
2
Content available remote

Light Modulation in Elliptical-Core Liquid Crystal Fibers

100%
Nasiłowski T., Woliński T.
Acta Physica Polonica A
|
1999
|
vol. 95
|
issue 5
767-775
EN
An original idea of external parameters (electric field, temperature, pressure etc.) monitoring is presented. After the theoretical analysis of the light modulation in a liquid crystal and elliptical-core anisotropic fiber the latest experimental results are reported. Due to measurands-induced changes in birefringence and propagation conditions the liquid crystal and elliptical-core fiber uniting unique advantages of liquid crystals and quality of fiber technology acts as a sensing medium and can be used for continuous monitoring of different external parameters.
3
Content available remote

Modelling of Nonlinear Crosstalk in Optical Fibre Wavelength-Division Multiplexed Telecommunication Systems

63%
Szczęsny W., Marciniak M.
Acta Physica Polonica A
|
1999
|
vol. 95
|
issue 5
859-867
EN
Nonlinear effects in optical fibres play an important role for transmission parameters in wavelength-division multiplexed telecommunication systems. Those effects cause an additional attenuation, distortion and inter-channel interference of the multi-wavelength optical signal. Therefore, it is important to optimise inter-channel wavelength span in a wavelength-division multiplexed system, and also the optical power and transmission bit-rate. Another drawback is a limitation of the number of the transmitted optical channels and network nodes. The paper reports the results of the analysis and computer simulations of the wavelength-division multiplexed transmission through fibre link in a presence of nonlinear effects: self-phase modulation, cross-phase modulation, Raman scattering, four-wave mixing. The analysis enables network designers to evaluate the system performance and to optimise transmission parameters.
4
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Content available

Photonic Crystal Fibers

63%
Buczynski R.
Acta Physica Polonica A
|
2004
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vol. 106
|
issue 2
141-167
EN
Photonic crystal fibers are a new class of optical fibers. Their artificial crystal-like microstructure results in a number of unusual properties. They can guide light not only through a well-known total internal reflection mechanism but using also photonic bandgap effect. In this paper different properties possible to obtain in photonic crystal fibers are reviewed. Fabrication and modeling methods are also discussed.
5
Content available remote

Optical Sensor of the Magnetic Field in Electrical Power Engineering

51%
Barczak K., Pustelny T., Zycki Z., Blazejczyk T., Dorosz D.
Acta Physica Polonica A
|
2010
|
vol. 118
|
issue 6
1090-1092
EN
The authors of the presented paper deal with investigations concerning applications of the optical fiber sensor of the magnetic field in electric DC engines with permanent magnets. The aim of the sensor is to measure the state of magnetization of permanent magnets (basing on the measurements of magnetic field induction). The knowledge of the state of magnetization helps to decide whether permanent magnets need to be additionally magnetized in order to prevent damages of the whole engine. This can be done automatically, even when the engine is running. For the purpose the Faraday magnetooptic effect is used. The presented investigations concern an optical fiber sensor of the magnetic field provided with a glass rod characterized a high value of the Verdet constant as the sensing element. Thanks to the application of optical fibers the connection of the sensor head with the whole measuring system is constructed of insulating material without using of electrical connections.
6
Content available remote

Optical Fibre Current Sensor for Electric Power Industry

51%
Barczak K., Pustelny T., Dorosz D., Dorosz J.
Acta Physica Polonica A
|
2010
|
vol. 118
|
issue 6
1087-1089
EN
The paper deals with the optical fibre current sensor based on new optical fibre made of glass with a high value of refractive index. This kind of glass was developed to meet the requirements of these optical fibres. The aim of investigations was to develop a new optical fibre with adequate magneto-optical properties and a relatively weak linear birefringence resulting from the process of its production. These features are of essential importance for optical fibre current sensors. The results of investigations concerning such optical fibres have been presented, displaying satisfactory magneto-optical properties, as well as only low linear birefringence induced by stresses arising in the course of their manufacturing.
7
Content available remote

Nd^{3+}/Yb^{3+} Doped Phosphate and Antimony Glasses for Optical Fibre Source

51%
Dorosz D., Żmojda J., Kochanowicz M., Dorosz J.
Acta Physica Polonica A
|
2010
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vol. 118
|
issue 6
1108-1112
EN
In the article there are presented two different series of glass: fluorophosphate with molar composition: 65P_2O_5-8Al_2O_3-2BaO-5BaF_2-6ZnF_2-5Na_2O-6MgF_2-3B_2O_3 and antimony glasses 40Sb_2O_3-3Al_2O_3-57SiO_2 doped with Nd^{3+} and Yb^{3+} ions. Dopant contents influence efficient spatial overlapping of emission level for neodymium and absorption level for ytterbium was analyzed. While exciting the produced glasses with a laser diode (λ = 808 nm) a broad luminescence spectrum (Δλ = 100 nm) has been obtained in both cases in the vicinity of 1 μm, being the superposition of the following transitions: ^4F_{3/2} → {^4I_{11/2}} for Nd^{3+} and ^2F_{5/2} → {^2F_{7/2}} for Yb^{3+}. Based on the luminescence measurements the probability of non-radiative energy transfer was described. Because of a small difference in energy ( ≈1190 cm^{-1}) between the laser levels of neodymium and ytterbium the resonant process of energy transfer has been obtained.
8
Content available remote

Multicore Optical Fibres for an External Talbot Cavity

51%
Dorosz D., Kochanowicz M., Dorosz J.
Acta Physica Polonica A
|
2009
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vol. 116
|
issue 3
298-301
EN
In the paper the application of multicore optical fibres in phased-locked high power lasers is presented. The manufacturing and properties of multicore active optical fibres were presented. The thermally stable aluminosilicate glass doped with Nd^{3+} (0.5 mol%) ions were melted and used as cores in manufactured multicore optical fibres. Two configurations of double clad multicore optical fibres with the circular array containing 15 and 30 Nd^{3+} doped cores on ring inside a large pump clad were realized. Absorption and luminescence spectra of obtained glasses and fibres were presented. An external plane mirror located at certain distance of the array forms the basic Talbot cavity. The possibilities of mode selection and phase-locking by using Talbot resonator applied to fabricated multicore fibres were investigated.
9
Content available remote

Effect of Temperature on Upconversion Luminescence in Yb^{3+}/Tb^{3+} Co-Doped Germanate Glass

51%
Kochanowicz M., Dorosz D., Zmojda J., Miluski P., Dorosz J.
Acta Physica Polonica A
|
2013
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vol. 124
|
issue 3
471-473
EN
In the article effect of temperature on the cooperative energy transfer in germanate glass co-doped with $Yb^{3+}/Tb^{3+}$ under 976 nm laser diode pumping was investigated. The optimization of $Tb^{3+}$ concentration on the upconversion luminescence was determined. Strong luminescence at 489, 543, 586, 621 nm corresponding to $^{5}D_{4} → ^{7}F_{J}$ (J = 6,4,3) transitions and luminescence at 381, 415, 435 nm resulting from $^{5}D_{3}, ^{5}G_6 → ^{7}F_{J}$ (J=6,5,4) transitions were presented. The highest upconversion emission intensity was obtained in glass co-doped with $0.7Yb_{2}O_{3}/0.7Tb_{2}O_{3}$ (mol%). The effect of temperature on the luminescent properties of germanate glass in the range of 5-250°C indicates the presence of competing phenomena: an increase in the effective absorption cross-section of $Yb^{3+}$ ions donor as a function of temperature and migration of energy between pairs of ions $Yb^{3+}-Yb^{3+}$ and of multiphonon excitation levels $^{7}F_{J}$.
10
Content available remote

Optical Sensor for Measurements of the Blood Chamber Volume in the POLVAD Prosthesis - Static Measurements

51%
Konieczny G., Pustelny T., Marczyński P.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 3
479-482
EN
The paper presents results of extended static measurements of a newly developed optical system for temporary blood chamber volume measurements in the Polish Ventricular Assist Device. The paper additionally introduces a modified measurement stand and improvements of the measurements. Exemplary results acquired with principal components analysis are shown and future development plans of an optical measurement system are stated.
11
Content available remote

Quasi-Dynamic Testing of an Optical Sensor for Measurements of the Blood Chamber Volume in the POLVAD Prosthesis

51%
Konieczny G., Pustelny T., Marczyński P.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 3
483-485
EN
The article presents further developments of an optical system to be used in temporary blood volume measurements in the Polish ventricular assist device. The research focuses on quasi-dynamic measurements (flow rate of 5 ml/s). Characteristics of signals from selected configurations of optical transmitters and receivers are shown. A volume approximation using a PCA algorithm supported by a LRS function is introduced. Plans of further development are stated.
12
Content available remote

State of the Work Diagram of the Artificial Heart

51%
Konieczny G., Opilski Z., Pustelny T., Maciak E.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 3
344-347
EN
This paper presents the results of investigations on novel pressure measurement methods to be for used in the project "Polish Artificial Heart". The investigations concerned possible pressure sensors for noninvasive blood pressure measurements in selected points around the pneumatic ventricular assist device (POLVAD). The fiber pressure sensor and the possibility of pressure measurements with piezofoils were tested. The paper includes preliminary results and development plans.
13
Content available remote

Results of Experiments with Fiber Pressure Sensor Applied in the Polish Artificial Heart Prosthesis

51%
Konieczny G., Opilski Z., Pustelny T., Gacek A., Gibinski P., Kustosz R.
Acta Physica Polonica A
|
2010
|
vol. 118
|
issue 6
1183-1185
EN
The following paper introduces the problem of noninvasive pressure measurements in Polish artificial heart prosthesis. The pressure sensor is proposed and introduced, and preliminary tests are shown. The paper deals with the proposed sensing elements, requirement noninvasive solution and preliminary tests of polyurethane membrane transmission. The paper includes also experimental results of a fiber pressure sensor introducing noninvasive pressure measurements with pressure transmission through a polyurethane tube wall.
14
Content available remote

Beam Quality of Multicore Fibre Lasers

51%
Kochanowicz M., Dorosz D., Żmojda J., Dorosz J.
Acta Physica Polonica A
|
2010
|
vol. 118
|
issue 6
1177-1182
EN
In the paper the beam quality of the phase-locked multicore fibre lasers was investigated. The beam quality factor (BQF) of the coherently combined beam of the multicore fibre lasers should be determinate as the laser optical output power in a central peak far-field bucket divided by the total optical output power radiating from the effective near-field. Classical M^2 factor is not proper for evaluating the beam quality of phase-locked multicore fibre lasers because it degrades with the increasing number of cores. The beam quality factor of the manufactured multicore fibres equals: 7-core hexagonal structure fibre (BQF = 0.71, V = 2.4), 5-core (BQF = 0.70, V = 2.4), 30-core circular structure of core optical fibre laser possesses the lowest beam quality factor (BQF = 0.48, V = 2.4). However, the angular divergence of the central peak is reduced in proportion to the number of cores generating mutually coherent radiation. Numerical simulation shows that standard deviation of the phase error below 15° has an inconsiderable impact on the laser beam quality. The luminescence spectra of the fabricated constructions: 5-core, 7-core and 30-core double clad multicore optical fibres doped with Nd^{3+} were measured.
15
Content available remote

Scar Selection in an Optical Fibre

51%
Doya V., Legrand O., Michel C., Mortessagne F.
Acta Physica Polonica A
|
2007
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vol. 112
|
issue 4
607-617
EN
A multimode optical fiber with a D-shaped cross-section has already been proved to constitute a privileged system to image wave functions of a chaotic system. Nevertheless, diffraction of light at the fiber input precludes the excitation of individual wave functions and particularly the scar modes we want to investigate. We show that a mechanism of scar modes selection can be induced by the introduction of a localized gain.
16
Content available remote

Hollow-Core Bragg Fiber for Bio-Sensing Applications

51%
Mileńko K., Hu D., Shum P., Woliński T.
Acta Physica Polonica A
|
2010
|
vol. 118
|
issue 6
1205-1208
EN
Theoretical analysis of propagation properties in a hollow-core Bragg fiber for bio-sensing applications has been demonstrated. Based on the Bragg fiber we propose a resonant sensor that operates on changes in refractive index of aqueous solution placed inside the hollow core. By using the transfer matrix method we analyzed the confinement loss of the TE_{01} mode in the hollow-core Bragg fiber. We have shown the influence of the fiber geometry on the changes in the confinement loss. Spectral sensitivity and resolution of the sensor are also presented.
17
Content available remote

Temperature Dependence Analysis of Mode Dispersion in Step-Index Polymer Optical Fibers

51%
Kovacevic M., Djordjevich A.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 4
649-651
EN
Temperature dependence of the mode dispersion is investigated for commercially available polymethyl methacrylate (PMMA) based step-index polymer optical fibers. An analytical expression is proposed describing the thermal variation of the fiber refractive index. This index decreases with increasing temperature as density of the polymer material drops. The study covered the temperature range from -60°C to 100°C. Results show that the modal dispersion decreases and the bandwidth increases with rising temperature.
18
Content available remote

Equilibrium Mode Distribution and Steady State Distribution in Step-Index Glass Optical Fibers

51%
Savović S., Djordjevich A., Drljača B., Simović A.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 4
655-657
EN
Using the power flow equation, we have examined mode coupling in a step-index multimode glass optical fiber. As a result, the coupling length at which the equilibrium mode distribution is achieved and the length of fiber required for achieving the steady-state mode distribution are obtained. These lengths are much longer for glass fiber than they are for plastic optical fibers. Our results are in good agreement with experimental results reported earlier.
19
Content available remote

Externally Liquid-Filled Photonic Crystal Fibers with High Output Intensity and Low Confinement Loss

51%
Hosseinpour M., Zendehnam A.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 6
1431-1438
EN
In this study, a Gaussian function is used to approximate the output intensity profiles of the externally liquid-filled photonic crystal fibers with various configurations. By decreasing the diameters of the five outer rings of the proposed photonic crystal fibers, the output intensity values are shown to be considerably increased for all of the studied configurations. A very high output intensity value with very low confinement loss (roughly 0 dB/m) can be achieved at λ =1.55 μ m by an appropriate design for the externally liquid-filled PCF with nanostructure.
20
Content available remote

Comparison of Methods for Calculating Coupling Length in Step-Index Optical Fibers

51%
Savović S., Djordjevich A., Drljača B., Kovačević M.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 4
652-654
EN
A recently reported function for calculation of the coupling length at which the equilibrium mode distribution is achieved in step-index plastic optical fibers is compared to a long established calculation method and to experimental findings. The recent function, while simpler to apply as it eliminates the need to numerically solve the power flow equation repeatedly for every case, is also more accurate for high numerical aperture (0.45 to 0.5) plastic optical fibers.
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