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We report on our latest developments of a planar fiber-chip-coupling scheme, using angle polished, polarization maintaining (PM) fibers. Most integrated photonic chip components are polarization sensitive and a suitable way to launch several wavelength channels to the chip with the same polarization is the use of PM fibers. Those impose several challenges at processing and handling to achieve a stable, permanent, and low-loss coupling. We present the processing of the fibers in detail and experimental results for our planar and compact fiber-chip-coupling technique. Summary High performance optical links using wavelength division multiplexing (WDM) are the future in detector instrumentation to increase data transmission bandwidth and reduce fiber count. A key component of such a system is a compact and efficient fiber-chip-coupling, connecting a photonic chip to the optical glass fibers. As most components of integrated photonic chips are polarization sensitive, one can use lossy on-chip polarization-insensitive couplers and polarization controllers or use polarization maintaining (PM) fibers to feed the required polarization directly from the lasers without the need of further manipulation. Our fiber-chip-coupling uses optical single mode glass fibers, whose tip is polished to a certain angle, so that light is reflected radially out of the fiber by total internal reflection at a defined angle, as shown in figure a). The fiber is positioned parallel to the chip surface with the tip above an on-chip grating coupler, so that the radially emitted light hits the grating coupler, which diffracts the light into an on-chip waveguide for further on-chip routing [1, 2]. PM fibers, however, are not axially symmetric due to the strain rods close to the fiber core to introduce birefringence (figure b)). Therefore fiber-chip-coupling becomes more challenging, as the angle of in-axis rotation has to be very well defined. For our process the angle is adjusted for the polishing process with an error of less than 0.3°. To achieve this, a special setup was developed (figure c)), which allows a precise fiber rotation before gluing the fibers to a fiber holder for polishing. For alignment, the front facet of a cleaved PM fiber with its core, cladding, and, most important, strain rods is imaged by a camera with a microscope objective. The camera picture is analyzed by a machine vision system, extracting the contours of the fiber and the strain rods, calculating the rotation angle and indicating if the angle is in an acceptable range. To display the glass strain rods inside the cladding glass, special lighting and contrast enhancement is required. The following polishing process is essential for a low-loss coupling, as the angle of the polished surface to the fiber axis and the surface quality are equally important. To maintain the polishing angle, a special polishing fixture with a parallelogram guidance was developed and 3D-printed (figure d). Several silicon carbide grinding discs and diamond suspensions with decreasing grain sizes were used for polishing. After removing the polished fibers from their respective holders, a final thermal cleaning and fine polishing step was used to get a smooth mirror surface. We will present the setup to initially adjust the PM fibers for polishing, the optimized polishing process providing a recipe to reproduce the results, as well as measurement results of fiber-chip-coupling experiments. [1] D. Karnick et al., ”Optical Links for Detector Instrumentation: On-Detector Multi-Wavelength Silicon Photonic Transmitters” JINST, DOI 10.1088/1748-0221/12/03/C03078 [2] D. Karnick et al., “Efficient, easy-to-use, planar fiber-to-chip coupling process with angle-polished fibers”, 67th ECTC, DOI 10.1109/ECTC.2017.245

WOS: 000519806700073, In this study, composites composed of glass fiber reinforced-epoxy laminates interleaved with electrospun polyvinylchloride (PVC) nano-fibres were designed for radar absorption investigations. The laminated composites which were produced in special molds were obtained by placing woven glass fibers between each of PVC nanofiber mats, and the composites were produced in three different forms as pure, multi-walled carbon nanotubes doped and graphene doped. The morphologies of the PVC nanofiber mats were analyzed by scanning electron microscope. The radar absorption efficiencies of the composites in the individual and different combinations were measured in the 3-8 GHz frequency band. Experimental results show that the produced graphene-added composite material has improvable microwave absorption effect at several points in 3-8 GHz band to provide excellent absorption in future studies. The graphene doped structure was found to have a certain absorption characteristic up to 33.82% at a constant frequency. Besides, various strong absorption frequency points have been obtained in the related frequency range. The cascaded graphene doped composite layers can provide broadband absorption for stealth technology.

Presently, fiber reinforced materials are used for many industrial applications. Laser transmission welding (LTW) is a suitable method to join these materials. For multiple thermoplastics, the weld seam quality is affected by the amount of moisture content in the joining members. For LTW, heat is applied to the welding members and water in the composite changes phase from liquid to gas. Increasing the gas content can lead to detrimental cavities in the weld seam. Therefore, experiments were performed to investigate the influence of the laser focal geometry on the generation of cavities. Different focal geometries lead to different levels of process heat generation which affects the amount of vaporization. The experiments were conducted with endless glass fiber reinforced polyetherimide and endless carbon fiber reinforced polyetherimide. These samples were tested for their weld seam strength and the results were correlated to the moisture content and laser beam geometry. © 2016 The Authors.

The development of single mode chalcogenide glass fibers as wavefront filter for the DARWIN mission is reported. Melting procedures and different preform techniques for manufacturing core-cladding chalcogenide fibers are described. Bulk glass samples on the basis of Te-As-Se- and high Te-compositions have been characterized optically, by measurement of the absorption spectrum and the refractive index in the region 4 – 20 μm. Several chalcogenide core-cladding glass fiber configurations have been drawn and examined by microscopy. The mode propagation behaviour and numerical aperture of fiber samples have been determined by far field intensity distribution measurements, using a CO2 laser at 10.6 μm. Single mode waveguide performance has been demonstrated for several fiber samples, coated with an absorbing Gallium layer for stripping of cladding modes.

The development of single mode chalcogenide glass fibers as wavefront filter for the DARWIN mission is reported. Melting procedures and different preform techniques for manufacturing core-cladding chalcogenide fibers are described. Bulk glass samples on the basis of Te-As-Se- and high Te-compositions have been characterized optically, by measurement of the absorption spectrum and the refractive index in the region 4 – 20 μm. Several chalcogenide core-cladding glass fiber configurations have been drawn and examined by microscopy. The mode propagation behaviour and numerical aperture of fiber samples have been determined by far field intensity distribution measurements, using a CO2 laser at 10.6 μm. Single mode waveguide performance has been demonstrated for several fiber samples, coated with an absorbing Gallium layer for stripping of cladding modes.

Sisal fibre can potentially replace glass fibre in natural fibre composites. This study focuses on the environmental performance of sisal fibre production by quantifying the greenhouse gas (GHG) emissions and energy use of producing sisal fibre in Tanzania and Brazil using life cycle assessment (LCA), based on region-specific inventory data. The results show that sisal fibre production has much lower GHG emissions (75–95%) and non-renewable energy use (85–95%) compared to glass fibre on a kg-basis, which is in line with published LCAs on natural fibres. Sisal fibre's GHG emissions are strongly influenced by potential methane emissions arising from the wet disposal of sisal leaf residues. Furthermore, because the direct energy and material requirements of sisal fibre production are low, its environmental performance is shown to vary strongly based on local practices such as residue disposal and fertiliser use, and is also sensitive to transportation distances. Several improvement options are explored to understand potential improvements in environmental sustainability. The most attractive option is limiting inadvertent methane emissions occurring at residue disposal sites, for instance by using them for the production of biogas. © 2017 Elsevier Ltd

Sisal fibre can potentially replace glass fibre in natural fibre composites. This study focuses on the environmental performance of sisal fibre production by quantifying the greenhouse gas (GHG) emissions and energy use of producing sisal fibre in Tanzania and Brazil using life cycle assessment (LCA), based on region-specific inventory data. The results show that sisal fibre production has much lower GHG emissions (75–95%) and non-renewable energy use (85–95%) compared to glass fibre on a kg-basis, which is in line with published LCAs on natural fibres. Sisal fibre's GHG emissions are strongly influenced by potential methane emissions arising from the wet disposal of sisal leaf residues. Furthermore, because the direct energy and material requirements of sisal fibre production are low, its environmental performance is shown to vary strongly based on local practices such as residue disposal and fertiliser use, and is also sensitive to transportation distances. Several improvement options are explored to understand potential improvements in environmental sustainability. The most attractive option is limiting inadvertent methane emissions occurring at residue disposal sites, for instance by using them for the production of biogas. © 2017 Elsevier Ltd

Sisal fibre can potentially replace glass fibre in natural fibre composites. This study focuses on the environmental performance of sisal fibre production by quantifying the greenhouse gas (GHG) emissions and energy use of producing sisal fibre in Tanzania and Brazil using life cycle assessment (LCA), based on region-specific inventory data. The results show that sisal fibre production has much lower GHG emissions (75–95%) and non-renewable energy use (85–95%) compared to glass fibre on a kg-basis, which is in line with published LCAs on natural fibres. Sisal fibre's GHG emissions are strongly influenced by potential methane emissions arising from the wet disposal of sisal leaf residues. Furthermore, because the direct energy and material requirements of sisal fibre production are low, its environmental performance is shown to vary strongly based on local practices such as residue disposal and fertiliser use, and is also sensitive to transportation distances. Several improvement options are explored to understand potential improvements in environmental sustainability. The most attractive option is limiting inadvertent methane emissions occurring at residue disposal sites, for instance by using them for the production of biogas. © 2017 Elsevier Ltd

International audience; The generation of mid-infrared (mid-IR) radiation, ranging from 2 - 5 μm, is getting much attention in recent years thanks to many applications it can be used for, e.g. in free space optical communication, range finding, counter measures and remote chemical sensing systems. It also plays an increasing role in medicine, for instance in optical tissue ablation or optical coherence tomography, owing to the high water absorption in that wavelength range. In this research study, a ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fluoride fiber is pumped by a Q-switched mode-locked (QML) thulium (Tm3+)-doped double-clad silica fiber laser, emitting at around 2 μm, to generate mid-IR supercontinuum (SC). Further spectral broadening of this SC radiation is achieved by coupling it into a chalcogenide arsenide-selenide (AsSe) photonic crystal fiber (PCF). An output power of 24 W at 2 μm has been achieved in QML operation for the Tm3+-doped fiber laser. The SC output power from the ZBLAN fiber has been 7.8 W with a spectrum extending to approximately 4.1 μm. For further wavelength broadening experiments, a long-wave-pass filter with a 3 dB edge around 3.6 μm has been implemented between the ZBLAN and the AsSe fiber to cut out the residual pump light at 2 μm and the radiation between 2 μm and 3.5 μm. The pump power was approximately 120 mW with a spectrum from 3.5 μm to 3.9 μm. First proof of principal experiments has been performed with 20 mW of averaged output power and a spectrum extending to 4.9 μm. The coupling efficiency of the SC radiation from the ZBLAN fiber into the AsSe fiber has been around 30%. © 2016 SPIE.

International audience; We developed the extrusion method to prepare arsenic-free chalcogenide glass fibers with glass cladding. By using the double nested extrusion molds and the corresponding isolated stacked extrusion method, the utilization rate of glass materials was greatly improved compared with the conventional extrusion method. Fiber preforms with optimal stability of core/cladding ratio throughout the 160 mm length were prepared using the developed extrusion method. Typical fiber structure defects between the core/cladding interface, such as bubbles, cracks, and core diameter variation, were effectively eliminated. Ge-Sb-Se/S chalcogenide glasses were used to form a core/cladding pair and fibers with core/cladding structure were prepared by thermally drawing the extruded preforms. The transmission loss, fiber bending loss, and other optical characters of the fibers were also investigated. © 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).

cited By 11; International audience; The present paper investigates glass fibre flaw size distributions. Two commercial fibre grades (HP and HD) mainly used in cement-based composite reinforcement were studied. Glass fibre fractography is a difficult and time consuming exercise, and thus is seldom carried out. An approach based on tensile tests on multifilament bundles and examination of the fibre surface by atomic force microscopy (AFM) was used. Bundles of more than 500 single filaments each were tested. Thus a statistically significant database of failure data was built up for the HP and HD glass fibres. Gaussian flaw distributions were derived from the filament tensile strength data or extracted from the AFM images. The two distributions were compared. Defect sizes computed from raw AFM images agreed reasonably well with those derived from tensile strength data. Finally, the pertinence of a Gaussian distribution was discussed. The alternative Pareto distribution provided a fair approximation when dealing with AFM flaw size. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Injection molded polymer composite gears are being used in many power and motion transmission applications. In order to widen the utilization of reinforced polymers for precision motion transmission and noise less applications, the quality or accuracy of molded gears should be increased. Since the injection molded gear quality is significantly influenced by the material shrinkage behaviour, there is a need to understand the influence of fiber orientation on part shrinkage behaviour and hence the gear quality. Unreinforced and 20% short glass fiber reinforced Nylon 6/6 spur gears were injection molded in the laboratory and computer aided simulations of gear manufacturing was also carried out. Results of the mold flow simulation of gear manufacturing were correlated with the actual fiber orientation and measured metrological parameters of the molded gears. Actual orientation of the fibers near the tooth profile, weld line region and injection points of molded gears were observed using optical microscope. Fiber alignment along the tooth profile restricts shrinkage and induces anisotropic shrinkage, which significantly decreases the deviation of involute profile parameter from the design value. Fibers embedded in the molded skin surface increases the gear tooth profile form and lead form deviations. Non-alignment of fibers across the gear tooth section increases the tooth thickness, tooth-to-tooth spacing and radial runout deviations from design values. � 2007 Elsevier Ltd. All rights reserved.

Glass fiber reinforced vinyl ester polymer composites filled with clay particles were synthesized by a hand lay-up technique with the addition of methy ethyl ketone peroxide (MEKP), cobalt napthalate and benzoyl peroxide. Mechanical and thermal properties of vinyl ester-glass fiber composite and clay particles dispersed vinyl-glass fiber hybrids were investigated in the present work. The hybridization effect of nanoclay dispersion in vinyl ester-fiber composite was discussed. Enhanced mechanical, thermal and vibration properties were observed in nanoclay dispersed composites over vinyl ester-glass fiber composite. � SAGE Publications 2008.

We theoretically demonstrate a novel approach for generating Mid-InfraRed SuperContinuum (MIR SC) by using concatenated fluoride and chalcogenide glass fibers pumped with a standard pulsed Thulium (Tm) laser (TFWHM=3.5ps, P0=20kW, νR=30MHz, and Pavg=2W). The fluoride fiber SC is generated in 10m of ZBLAN spanning the 0.9–4.1μm SC at the −30dB level. The ZBLAN fiber SC is then coupled into 10cm of As2Se3 chalcogenide Microstructured Optical Fiber (MOF) designed to have a zero-dispersion wavelength (λZDW) significantly below the 4.1μm InfraRed (IR) edge of the ZBLAN fiber SC, here 3.55μm. This allows the MIR solitons in the ZBLAN fiber SC to couple into anomalous dispersion in the chalcogenide fiber and further redshift out to the fiber loss edge at around 9μm. The final 0.9–9μm SC covers over 3 octaves in the MIR with around 15mW of power converted into the 6–9μm range.

Fluoride phosphate (FP) glass fibres have been developed for radiation dosimetry based on the mechanism of optically stimulated luminescence (OSL). Doping with Tb3+ ions improved the materials sensitivity; for samples melted in oxidising conditions, OSL intensity was increased from 8:8 × 105 cnts/g/Gy for undoped glass to 812:3 × 105 cnts/g/Gy for Tb3+-doped glass. The radiation sensor performance of Tb3+-doped glass fibres under both beta and X-ray irradiation demonstrated the capability of the fibres for radiation dosimetry applications. Refereed/Peer-reviewed

Projektna naloga vsebuje opis in področja uporabe mikrovlaken v betonu. V prvem vsebinskem poglavju so predstavljene osnovne značilnosti mikrovlaken in njihova delitev. Nato smo opisali mehanske lastnosti betona, ki se z dodajanjem mikrovlaken izboljšajo. Predstavljeni so najpogostejši primeri uporabe mikroarmature in njihov način vgrajevanja. Narejena je tudi stroškovna analiza uporabe klasične armature in mikrovlaken ter vrednostna analiza glede na različne lastnosti materiala in načine vgrajevanja. V sklepu so podane glavne ugotovitve iz projektne naloge. This project assignment describes fibers and the fields of usage of fibers in concrete. In the first chapter the basic characteristics of fibers and their division are described. Next the mechanical characteristics of concrete, which are strengthened with adding fibers, were described. The most common ways of micro fixture and the manner of its integration are presented. We also made a cost analysis of usage of classic fixture and fibers and a cost analysis based on different characteristics of material and ways of integration. Basic findings from this project assignment are presented in the conclusion.

Incorporation of soluble bioactive glass fibres into biodegradable polymers is an interesting approach for bone repair and regeneration. However, the glass composition and its surface properties significantly affect the nature of the fibre-matrix interface and composite properties. Herein, the effect of Si and Fe on the surface properties of calcium containing phosphate based glasses (PGs) in the system (50P 2O 5-40CaO-(10-x)SiO 2-xFe 2O 3, where x = 0, 5 and 10 mol.%) were investigated. Contact angle measurements revealed a higher surface energy, and surface polarity as well as increased hydrophilicity for Si doped PG which may account for the presence of surface hydroxyl groups. Two PG formulations, 50P 2O 5-40CaO-10Fe 2O 3 (Fe10) and 50P 2O 5-40CaO-5Fe 2O 3-5SiO 2 (Fe5Si5), were melt drawn into fibres and randomly incorporated into poly(lactic acid) (PLA) produced by melt processing. The ageing in deionised water (DW), mechanical property changes in phosphate buffered saline (PBS) and cytocompatibility properties of these composites were investigated. In contrast to Fe10 and as a consequence of the higher surface energy and polarity of Fe5Si5, its incorporation into PLA led to increased inorganic/organic interaction indicated by a reduction in the carbonyl group of the matrix. PLA chain scission was confirmed by a greater reduction in its molecular weight in PLA-Fe5Si5 composites. In DW, the dissolution rate of PLA-Fe5Si5 was significantly higher than that of PLA-Fe10. Dissolution of the glass fibres resulted in the formation of channels within the matrix. Initial flexural strength was significantly increased through PGF incorporation. After PBS ageing, the reduction in mechanical properties was greater for PLA-Fe5Si5 compared to PLA-Fe10. MC3T3-E1 preosteoblasts seeded onto PG discs, PLA and PLA-PGF composites were evaluated for up to 7 days indicating that the materials were generally cytocompatible. In addition, cell alignment along the PGF orientation was observed showing cell preference towards PGF. © 2011 Springer Science+Business Media, LLC.

The relationships between the material parameters, i.e., the fiber fineness, porosity, areal density, layering sequence, and airflow resistivity with the normal-incidence sound absorption coefficient of nonwoven composites consisting of three layers have been studied. The monofiber or multifiber needle-punched nonwovens included poly(lactic acid) (PLA), polypropylene (PP), glass fiber, and hemp fibers. Air flow resistivity was statistically modeled and was found to increase with decreasing fiber size and nonwoven porosity. The former models developed for glass fiber mats in the literature were found to be inconsistent with the air flow resistance of the nonwovens reported below. The effects of the layering sequence on air flow resistivity and sound absorption were obtained. It was found that when the layer including reinforcement fibers, i.e., hemp or glass fiber, faced the air flow/sound source, the air flow resistance and the absorption coefficient were higher than the case when the layer including reinforcement fibers was farthest from the air flow/sound source. The difference was more pronounced if there was a greater difference between the resistivity values of the constituent layers of the nonwoven composite. Sound absorption coefficient was statistically modeled in terms of air flow resistivity and frequency. © 2011 Wiley Periodicals, Inc.

cited By 6; International audience; Many inorganic fibers are sensitive to subcritical crack growth activated by the environment. Failure occurs even though the applied stress is much smaller than the fracture stress. This mechanism has been extensively investigated on ceramics, glasses and glass fibers, essentially at room temperature, and has recently been shown in SiC-based fibers at high temperatures. The present paper proposes a very powerful approach to static fatigue. It is based on tests performed on multifilament tows under deformation-controlled conditions (the load relaxation technique). This technique, which has not been used previously owing to practical difficulties of deformation control during long-term tests, permits the application of identical constant stresses on all the fibers during a single test. Thus it provides a statistically significant rupture time database containing just as many data as there are fibers in the tows. Bundles of ∼2000 E-glass filaments were used in the present paper. The samples were immersed in water during the static fatigue tests. Crack velocity-stress intensity factor diagrams for single filaments were derived from experimental stress-rupture time data. A closed form expression for statistical distributions of fiber lifetimes was established, and was found to compare fairly well with the experimental results, which assessed the approach and validated new findings. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

This paper deals with the effect of clay addition on improving the mechanical properties of epoxy polymer and glass fiber-reinforced epoxy-clay hybrid composites. The clays used in the present system were alkyl ammonium treated montmorillonite (MMT) based organoclay (OC) and unmodified MMT clay (UC). The OC and UC were added individually to epoxy polymer and glass fiber-reinforced epoxy composites. Structure and morphology of epoxy filled with OC and UC were examined by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. It is observed that the clay nanolayer dispersion takes place in a polymer matrix filled with OC particles. However, the UC filled composites show the formation of micro-composites. The effects of clay addition (1—3%, 5% and 10% by weight) in epoxy polymer shows that OC filled composites possess enhanced tensile strength over UC filled composites. A similar result is observed in the OC filled glass fiber-reinforced epoxy composites. Dynamic mechanical analysis (DMA) and thermogravimetry analysis (TGA) of hybrids show that the addition of OC increases the thermal properties of epoxy-glass fiber more than that of UC filled hybrids.

International audience; Using short natural fibers in thermoplastic composites not only improves polymer mechanical properties, but also allows making materials that are lightweight compared to composites reinforced with glass fibers. The main applications are plastic parts for automobiles,packaging and construction.Natural fibers come from renewable resources, are cheap and easily available. However, there are a lot of morphology and properties differences between glass and natural fibers. Glass fibers have a homogeneous composition and diameter, are straight, stiff and brittle, but natural fibers usually have a various chemical compositions and appear as thick and stiff bundles and/or as thin flexible elementary fibers.During injection molding process, fibers are flowing and then, after material solidification, their dispersion and orientation are "frozen". While the microstructure of glass fibers reinforced thermoplastic is well known, natural fibers case is still not studied in details. Will natural fibers take the same orientation in the injected parts as glass fibers? How natural fibers flexibility influences their orientation? Do natural fibers remain curved in composites?The work objective is to analyze and to understand the microstructure of flax fiber-polymer-composite. Fibers were mixed with polypropylene in a twin screw extruder, pelletized and injected in a rectangular-shaped mold. By optical microscopy in transmitted and reflected light accompanied by image analysis, fiber orientation and curvature were quantified, at different depths and locations in the injected parts.Results were related with shear and elongation flows experienced by the material during processing.