Distributed fluorescent optical fiber proximity sensor: Towards a proof of concept

Fluorescent fibers are optical fibers which emit light as a response to an incident phenomenon, usually an incident light. Operation depends on the doping dyes, which determine specific fluorescence and optical characteristics useful in the development of optical sensors. In this work we propose a low-cost distributed proximity sensor implemented using a red fluorescent fiber, to provide a security option for a surface plasmon resonance system. Operation of the proposed sensor relies on having the incident illumination intensity varied by the presence or absence of an obstacle in the vicinity of the sensing element. This will influence the radiated fluorescence accordingly. The proposed setup for the implementation of the optical proximity sensor assumes having a high brightness LED deployed for axial fiber illumination and a blue LED for side illumination. Electronic processing then accounts for gain and digitization. Measurement results of the prototype validate the proposed concept

Problemy ludnościowe na Litwie, Łotwie i w Estonii na tle krajów Unii Europejskiej

Population Problems in Lithuania, Latvia and Estonia versus the European Union Member StatesProblemy ludnościowe na Litwie, Łotwie i w Estonii na tle krajów Unii Europejskie

The Prowler IADS performance evaluation tool (PIPE)

The Prowler IADS Performance Evaluator is a computer simulation model of an airstrike protected by electronic countermeasures platforms. It is designed for integration into mission planning systems and analysis tools used to determine the effectiveness of electronic countermeasures or allocate scarce countermeasures equipment. PIPE's features include flexible hierarchical IADS specification, the capability to construct and calculate appropriate measures of performance, graphical presentation analysis results, mission visualizationNaval Postgraduate School, Monterey, California.http://archive.org/details/prowleriadsperfo00bailMonterey, California. Naval Postgraduate SchoolApproved for public release; distribution is unlimited

Up-conversion luminescence in low phonon heavy metal oxide glass co-doped with Er3+/Ho3+ ions

In this paper, heavy metal oxide glasses co-doped with erbium and holmium ions have been synthesized. Glass composition, based on bismuth and germanium oxides, has been selected in terms of high thermal stability (∆T = 125 °C), high refractive index (n = 2.19) and low maximum phonon energy (hνmax = 724 cm⁻¹). Up-conversion luminescence spectra under the 980 nm laser diode excitation have been observed as a result of radiative transitions within the quantum energy level structures of Er³⁺ and Ho³⁺ ions. Optimization of rare earth ions content has been conducted, the highest emission intensity in the visible wavelength range has been observed in glass co-doped with molar concentration 0.5 Er2O3 / 0.5 Ho2O3

Theoretical Investigation of Oxazine 170 Perchlorate Doped Polymeric Optical Fiber Amplifier

Optical signal amplification in the waveguiding structure of optical fibers can be used for optical telecommunication systems and new light sources constructions. Organic dyes doped materials are interesting for new applications in polymeric optical fibers technology due to their benefits (efficient fluorescence, high absorption cross section, and easy processing). This article presents a numerical simulation of gain in poly(methyl methacrylate) optical fiber doped by Oxazine 170 Perchlorate. The calculated gain characteristic for the used dye molar concentration (0.2·10-6–1.4·10-6) and pump power (1–10 kW) is presented. The fabricated fluorescent polymeric optical fiber is also shown. The presented analysis can be used for optical amplifier construction based on dye-doped polymeric optical fiber (POF)

Optical characterization of nano- and microcrystals of EuPO4 created by one-step synthesis of antimony-germanate-silicate glass modified by P2O5

Technology of active glass-ceramics (GC) is an important part of luminescent materials engineering. The classic method to obtain GC is based on annealing of parent glass in proper temperature and different time periods. Generally, only the bulk materials are investigated as a starting host for further applications. However, the effect of an additional heat-treatment process on emission and structural properties during GC processing is omitted. Here, we focus on the possibility of obtaining transparent glass-ceramic doped with europium ions directly with a melt-quenching method. The influence of phosphate concentration (up to 10 mol %) on the inversion symmetry of local environment of Eu3+ ions in antimony-germanate-silicate (SGS) glass has been investigated. The Stark splitting of luminescence spectra and the local asymmetry ratio estimated by relation of (5D0→7F2)/(5D0→7F1) transitions in fabricated glass confirms higher local symmetry around Eu3+ ions. Based on XRD and SEM/EDX measurements, the EuPO4 nano- and microcrystals with monoclinic geometry were determined. Therefore, in our experiment, we confirmed possibility of one-step approach to fabricate crystalline structures (glass-ceramic) in Eu-doped SGS glass without additional annealing process

Tm3+/Ho3+ co-doped germanate glass and double-clad optical fiber for broadband emission and lasing above 2 μm

In this paper, a 2 μm broadband emission under 796 nm laser diode excitation in low phonon energy GeO2-Ga2O3-BaO glass system is co-doped with 0.7Tm2O3/(0.07-0.7)Ho2O3 (mol%). The widest emission band (where the Tm3+ → Ho3+ energy transfer efficiency is 63%) was obtained for 0.7Tm2O3/0.15Ho2O3 co-doped glass from which a double-clad optical fiber was realized and investigated. Optimization of Tm3+/Ho3+ concentration enabled the acquisition of broadband amplified spontaneous emission (ASE) in double-clad optical fiber with a full width at half maximum (FWHM): 377 nm and 662 nm for 3 dB and 10 dB bandwidth, respectively. ASE spectrum is a result of the superposition of (Tm3+: 3H4 →Η3F4) 1.45 μm, (Tm3+: 3F4 → 3H6) 1.8 μm and (Ho3+:5I7 → 5I8) 2 μm emission bands. Hence, highly rare-earth co-doped germanate glass is characterized by a remarkably broader ASE spectrum than silica and tellurite fibers showed promising lasing properties for their further application in tunable and dual wavelength lasers

Spectroscopic properties of erbium-doped oxyfluoride phospho-tellurite glass and transparent glass-ceramic containing BaF2 nanocrystals

The ErF3-doped oxyfluoride phospho-tellurite glasses in the (40-x) TeO2-10P2O5-45 (BaF2-ZnF2) -5Na2O-xErF3 system (where x = 0.25, 0.50, 0.75, 1.00, and 1.25 mol%) have been prepared by the conventional melt-quenching method. The effect of erbium trifluoride addition on thermal, structure, and spectroscopic properties of oxyfluoride phospho-tellurite precursor glass was studied by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and Raman spectroscopy as well as emission measurements, respectively. The DSC curves were used to investigate characteristic temperatures and thermal stability of the precursor glass doped with varying content of ErF3. FTIR and Raman spectra were introduced to characterize the evolution of structure and phonon energy of the glasses. It was found that the addition of ErF3 up to 1.25 mol% into the chemical composition of phospho-tellurite precursor glass enhanced 2.7 µm emission and upconversion. By controlled heat-treatment process of the host glass doped with the highest content of erbium trifluoride (1.25 mol%), transparent erbium-doped phospho-tellurite glass-ceramic (GC) was obtained. X-ray diffraction analysis confirmed the presence of BaF2 nanocrystals with the average 16 nm diameter in a glass matrix. Moreover, MIR, NIR, and UC emissions of the glass-ceramic were discussed in detail and compared to the spectroscopic properties of the glass doped with 1.25 mol% of ErF3 (the base glass)

Structure and luminescence properties of transparent germanate glassceramics co-doped with Ni2+/Er3+ for near-infrared optical fiber application

An investigation of the structural and luminescent properties of the transparent germanate glass-ceramics co-doped with Ni2+/Er3+ for near-infrared optical fiber applications was presented. Modification of germanate glasses with 10–20 ZnO (mol.%) was focused to propose the additional heat treatment process controlled at 650 C to obtain transparent glass-ceramics. The formation of 11 nm ZnGa2O4 nanocrystals was confirmed by the X-ray diffraction (XRD) method. It followed the glass network changes analyzed in detail (MIR—Mid Infrared spectroscopy) with an increasing heating time of precursor glass. The broadband 1000–1650 nm luminescence ( exc = 808 nm) was obtained as a result of Ni2+: 3T2(3F) ! 3A2(3F) octahedral Ni2+ ions and Er3+: 4I13/2 ! 4I15/2 radiative transitions and energy transfer from Ni2+ to Er3+ with the efficiency of 19%. Elaborated glass–nanocrystalline material is a very promising candidate for use as a core of broadband luminescence optical fibers