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Optimization of microstructured fibers with germanium-doped core for broad normal dispersion range

Biedrzycki J., Tarnowski K., Urbańczyk W.

Opto-Electronics Review

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2018

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Vol. 26, No. 1

57--62

EN

We have numerically studied different designs of technologically feasible microstructured fibers with a germanium-doped core in order to obtain normal dispersion reaching possibly far in the mid infrared. Hexagonal, Kagome and the combination of both geometries were numerically examined with respect to different constructional parameters like pitch distance, filling factor of air holes, number of layers surrounding the core, and level of germanium doping in the core. Our analysis showed that the broadest range of normal dispersion reaching 2.81 μm, while keeping an effective mode area smaller than 30 μm², was achieved for a hexagonal lattice and a 40 mol% GeO₂ doped core. The proposed fibers designs can be used in generation of a normal dispersion supercontinuum reaching the mid-IR region.

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Emission of Polychlorinated Dibenzo-p-Dioxins (PCDDs) and Polychlorinated Dibenzofurans (PCDFs) from Underfiring System of Coke Oven Battery

Bigda R., Urbańczyk W., Mianowski A., Sobolewski A.

Journal of Ecological Engineering

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2017

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Vol. 18, nr 6

21--29

EN

A coke oven battery is not considered as a significant source of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) emissions; however, due to small amounts of chlorine in coal dioxins, dibenzofurans may be formed. The paper presents the attempts to determine the level of emission of PCDDs/PCDFs from the COB underfiring system and to confront the obtained results with the calculations based on the mass balance of chlorine in the coking process and reactions of both chlorophenols formation and PCDDs and PCDFs formation from mono- and polychlorophenols. There were PCDDs/PCDFs concentrations measured in flue gases from the underfiring system of two COBs at a Polish coking plant. The measurements included both an old and a new battery. The obtained concentrations of PCDDs/PCDFs were lower than reported in the literature (0.5-1.7 ng I-TEQ/Mgcoke), while the results for old COB were on average 3 times higher than for the new one. It was found that PCDDs/PCDFs emission from COB underfiring system is insignificant and that PCDDs/PCDFs formation during coal coking should consider the mechanisms of their formation from mono- and polychlorophenols, as well as the influence of process parameters on the synthesis.

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Optimization of detection system for low-coherence interferometric sensors based on highly birefringent fibers.

Nawrocka M.S., Urbańczyk W.

Optica Applicata

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2001

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Vol. 31, nr 1

231-250

EN

A demodulation system employing birefringent crystalline plates for decoding low-coherence interferometric sensors based on highly birefringent fibers was numerically analyzed in order to find its optimum construction. A numerical approach proposed allowed us to calculate how the parameters of the decoding system such as thickness and orientation of the crystalline plates, type of birefringent material, position of the detectors, and polarization characteristics of beam splitting plates influence the contrast of differential interference signals. Calculations were based on vectorial ray tracing algorithm applicable to isotropic as well as anisotropic media. The algorithm allowed determination of intersection coordinates with detector surface for ordinary and extraordinary rays, their phases, polarizations, and amplitudes, and finally the contrast of differential interference signals. Based on modeling results, general principles concerning system construction were formulated, which assure the highest possible contrast of interference signals and therefore maximum operation range of the sensor.

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Application of low-coherence interferometry to multiplexing of fiber-optic sensor based on highly birefringent fibers.

Urbańczyk W., Bock J., Witczyński M.

Optica Applicata

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1999

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Vol. 29, nr 1-2

181-190

EN

Results of experimental studies on coherence of a greater number of sensor based on highly birefringent fibers are presented. We propose a flexible detection system based on a Wollastone prism which allows demultiplexing of several serially connected pressure and temperature sensor. The proposed method of multiplexing is simple, inexpensive, and assures absolute accuracy of each multiplexed sensor about 0.5% of the full scale.