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1

Guided modes in capillary optical fibers

Romaniuk R. S.

Electronics and Telecommunications Quarterly

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2008

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Vol. 54, No 3

323-342

EN

A comparatively large group of capillary optical fibers, referred to in this paper as COF, consists of several families of optical filaments. The basic division line goes through the wave guidance mechanism. Two basic kinds of capillary optical fibers are of refractive and photonic mechanism of guided wave transmission. The work tries to compare wave modes in both kinds of optical fiber capillaries: refractive (RCOF) and photonic (PCOF). The differences are emphasized indicating prospective application areas of these fibers. Refractive COF carries most of the modal light in the ring-like, high-refraction, optical glass core encircling an empty capillary hole. Refractive capillary optical fibers are used widely for photonic instrumentation applications, due to the proximity of optical wave and capillary hole with the evanescent wave. The hole can be filled with a material subject to optical guided wave spectrometry. Photonic COF carries most of the light in air (or vacuum). Thus, photonic capillary optical fibers are considered for trunk optical communications, with guided wave travelling in vacuum rather than in glass - avoiding in this way the Rayleigh scattering. The fundamental mode in a refractive COF is LPoi or dark hollow beam (DHB) of light with zero intensity on fiber axis. The fundamental mode in a photonic COF is Gaussian beam with maximum intensity on fiber axis. The photonic COFs can be further divided to two basic groups: porous or holey/hollow and Bragg or OmniGuide fibers. These two kinds of PCOFs differ by the method of building a photonic band gap (PBG) around a capillary hole. The paper is a concise digest of fundamental kinds of singlemode (or low-order mode) COFs and their properties, with an emphasis on applications in two basic fields: instrumentation and telecommunications.

2

Capillary optical fiber - design, fabrication, characterization and application

Romaniuk R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2008

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Vol. 56, nr 2

87-102

EN

The paper presents a modification of capillary optical fibers fabrication method from an assembled glass preform. A change of dimensional proportions in the capillary optical fiber drawn from a single preform is allowed on-line via the control of overpressure and thermal conditions in the outflow meniscus which essentially lowers the manufacturing costs. These conditions are among the solutions (velocity fields) of the Navier-Stokes equations adapted to the capillary optical fiber pulling geometry and temperature distribution in the oven. The velocity fields give solutions to other quantities of interest such as flow rate, pulling force and fiber geometry. The calculation and experimental results for capillary optical fibers were shown in the following dimensional range: internal diameters 2-200 [mi]m, external diameters 30-350 [mi]m, within the assumed dimensional stability (including ellipticity) better than 1 %. The parameters of fabricated capillary optical fibers of high-quality low-loss optical multicomponent glasses were: losses 100 dB/km, mechanical strength above 1GPa with Weibull coefficient in the range 3-7, internal numerical aperture 0.1-0.3, external numerical aperture 0.1-0.3, core index 1.5-1.8, transparency 0.4-2 [mi]m, thermally and/or chemically conditioned internal surface, double polyimide protection layer, soft or hard jacketed, connectorized. The capillary optical fibers were applied in our own and several external laboratories in spectroscopy, refractometry, microfluidics and functional microoptic components. The paper summarizes a design, technological and application work on capillary optical fibers performed during a recent national research program devoted to optoelectronic components and modules.

3

Zastosowania światłowodów kapilarnych

Romaniuk R.

Elektronika : konstrukcje, technologie, zastosowania

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2006

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Vol. 47, nr 4

5-9

PL

Dokonano aktualnego przeglądu zastosowań światłowodów kapilarnych. Niektóre z tych zastosowań wynikają z klasycznych właściwości kapilar i urządzeń kapilarowych, takich jak reometria, elektroforeza, chromatografia kolumnowa, ale niektóre są związane ściśle z kopropagacją mikromasy z falą optyczną zanikającą lub falą optyczną o znacznym natężeniu.

EN

The paper updates and summarizes contemporary applications of capillary optical fibers. Some of these applications are straight consequence of the classical capillary properties and capillary devices like: rheometry, electrophoresis, column chromatography (gas and liquid). Some new applications are tightly connected with co-propagation (or counter-propagation) of micromass together with optical wave evanescent or of considerable intensity. Optical capillaries, filamentary and embedded, are turning to a fundamental component of nano- and micro MOEMS.