Specialty Fibers Research Articles

Measurement of a wide-range of X-ray doses using specialty doped silica fibres

Using six types of tailor-made doped optical fibres, we carry out thermoluminescent (TL) studies of X-rays, investigating the TL yield for doses from 20mGy through to 50Gy. Dosimetric parameters were investigated for nominal 8wt% Ge doped fibres that in two cases were co-doped, using B in one case and Br in the other. A comparative measurement of surface analysis has also been made for non-annealed and annealed capillary fibres, use being made of X-ray Photoelectron Spectroscopy (XPS) analysis. Comparison was made with the conventional TL phosphor LiF in the form of the proprietary product TLD-100, including dose response and glow curves investigated for X-rays generated at 60kVp over a dose range from 2cGy to 50Gy. The energy response of the fibres was also performed for X-rays generated at peak accelerating potentials of 80kVp, 140kVp, 250kVp and 6MV photons for an absorbed dose of 2Gy. Present results show the samples to be suitable for use as TL dosimeters, with good linearity of response and a simple glow curve (simple trap) distribution. It has been established that the TL performance of an irradiated fibre is not only influenced by radiation parameters such as energy, dose-rate and total dose but also the type of fibre.

Specialty Fibers for Terahertz Generation and Transmission: A Review

Terahertz (THz) frequency range, lying between the optical and microwave frequency ranges covers a significant portion of the electro-magnetic spectrum. Though its initial usage started in the 1960s, active research in the THz field started only in the 1990s by researchers from both optics and microwaves disciplines. The use of optical fibers for THz application has attracted considerable attention in recent years. In this paper, we review the progress and current status of optical fiber-based techniques for THz generation and transmission. The first part of this review focuses on THz sources. After a review on various types of THz sources, we discuss how specialty optical fibers can be used for THz generation. The second part of this review focuses on the guided wave propagation of THz waves for their transmission. After discussing various wave guiding schemes, we consider new fiber designs for THz transmission.

Thermal stability of specialty optical fiber coatings

Thermal stability of coatings used on specialty optical fibers is assessed via thermogravimetry (TG). The coating lifetimes are evaluated by analyzing dynamic TG curves and assuming a particular level of mass loss as a failure criterion. The studied coating systems include single and dual acrylate, fluorinated acrylate, epoxy, epoxy acrylate, silicone, silicone acrylate, silsesquioxane acrylate and polyimide materials. Processing the data by Arrhenius and Eyring equations indicates that a kinetic compensation effect (KCE) is observed for the decomposition processes, with distinct parameters for different classes of the coatings. Two aspects of the KCE are considered: (1) decomposition within several series of similar compounds in air and (2) decomposition of the same classes in different environments. An attempt is made to use the KCE to predict the lifetimes of the coatings at elevated temperatures.

Combining Untargeted and Targeted Proteomic Strategies for Discrimination and Quantification of Cashmere Fibers.

Cashmere is regarded as a specialty and luxury fiber due to its scarcity and high economic value. For fiber quality assessment, it is technically very challenging to distinguish and quantify the cashmere fiber from yak or wool fibers because of their highly similar physical appearance and substantial protein sequence homology. To address this issue, we propose a workflow combining untargeted and targeted proteomics strategies for selecting, verifying and quantifying biomarkers for cashmere textile authentication. Untargeted proteomic surveys were first applied to identify 174, 157, and 156 proteins from cashmere, wool and yak fibers, respectively. After marker selection at different levels, peptides turned out to afford much higher selectivity than proteins for fiber species discrimination. Subsequently, parallel reaction monitoring (PRM) methods were developed for ten selected peptide markers. The PRM-based targeted analysis of peptide markers enabled accurate determination of fiber species and cashmere percentages in different fiber mixtures. Furthermore, collective use of these peptide makers allowed us to discriminate and quantify cashmere fibers in commercial finished fabrics that have undergone heavy chemical treatments. Cashmere proportion measurement in fabric samples using our proteomic approach was in good agreement with results from traditional light microscopy, yet our method can be more readily standardized to become an objective and robust assay for assessing authenticity of fibers and textiles. We anticipate that the proteomic strategies presented in our study could be further implicated in discovery of quality trait markers for other products containing highly homologous proteomes.

Influence of Sodium Bisulfite and Lithium Bromide Solutions on the Shape Fixation of Camel Guard Hairs in Slenderization Process

Outstanding performance of natural camel hair has attracted much attention on the effective use of such specialty fiber to apparel textiles. In this paper, sodium bisulfide (SB) and lithium bromide (LB) solutions were used to process the camel guard hair before its slenderization. It is found that camel guard hair processed by SB solution shows the highest breaking elongation (~140%) due to the breakage of disulfide bonds (reflected by Raman spectra). LB ions result in the disruption of hair crystalline phase with slight benefit to the slenderization (determined by X-ray diffraction and differential scanning calorimetry). IR spectra indicate that hydrogen bonds of camel guard hair act as fixation switch in the programmed tensile test. It is discovered that guard hair reveals the best water-induced shape memory with 90% of stretching shape recovery, whereas the value remained to be 70% and 60% for hair processed by LB and SB solutions after breaking partial crystalline phase and disulfide cross-links separately (polymer net-points). The poorer shape memory of processed guard hair benefits its slenderization for more stable fixation of stretched length.

Research on the temperature sensing characteristics of triple cladding quartz specialty fiber based on cladding mode resonance

A triple-cladding quartz specialty fiber (TCQSF) temperature sensor based on cladding mode resonance is made. The sensor is fabricated by just splicing a short, few-centimeter-long segment of TCQSF between two standard single-mode fibers (SMFs), so the sensor structure is simple. In order to explain its sensing principle in detail, we assume that the TCQSF is equivalent to three coaxial waveguides based on coupling mode theory. Utilizing the scalar method and the relationship between Bessel function and mode field distribution of step-index circular symmetry waveguide, the mode field distribution of these waveguides and their characteristic equation can be easily obtained. Then the dispersion curves of each mode which is transmitted in the three waveguides can be calculated. The intersection between the fundamental core mode LP01(rod) in the rod waveguide and the cladding mode LP01(tube) in the tube waveguide I indicates that the two modes have the same propagation constant, and satisfy the phase-matching condition when the wavelength is 1563.7 nm which is known the resonant wavelength. And only when the sensor length is equal to the beatlength, can the light be coupled completely from the core to the fluorine-doped silica cladding. Thus, the cladding mode resonance phenomenon occurs and a band-stop filter spectrum will be obtained. Then the sensor is applied to the simulation calculation of the temperature sensing characteristics. With increasing temperature, both the refractive index of each layer and the sizes of the axial and radial fibers will change, which will finally lead to a big difference on the dispersion curves of LP01(rod) and LP01(tube). Therefore, the resonant wavelength shift of the sensor can be obtained by just calculating the dispersion curves of these two modes at different temperatures, and the scope of curvature sensitivity is 70.76-97.36 pm/℃. Finally, a straight forward experiment is performed to prove the temperature sensing properties. Experimental results show that the sensor has a sensitivity in temperature of 73.74 pm/℃ at 35 ℃-95 ℃, which is completely consistent with the theoreticaly calculatied results. Thus, the proposed sensor has the advantages of simple structure, easy fabrication, highly sensitivity, controlled cladding mode excitation, and so on. It can be used in industrial production, biomedical and other temperature sensing areas.

A temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fiber

In this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multi-mode fiber (SMMF), two sensors with different temperature sensing properties are obtained, and experimental results show that the temperature sensitivity can be up to 48.76 pm/°C in the range of 25—95 °C. Moreover, it has many advantages, including small size, high sensitivity, and simple structure. So it can be used in potential temperature sensing applications, such as industrial production, biomedical science, power electronics, and so on.

Gamma and x-ray irradiation effects on different Ge and Ge/F doped optical fibers

We performed electron paramagnetic resonance (EPR) measurements on γ and X ray irradiated Ge doped and Ge/F co-doped optical fibers. We considered three different drawing conditions (speed and tension), and for each type of drawing, we studied Ge and Ge/F doped samples having Ge doping level above 4% by weight. The EPR data recorded for the γ ray irradiated fibers confirm that all the samples exhibit a very close radiation response regardless of the drawing conditions corresponding to values used for the production of specialty fibers. Furthermore, as for the X irradiated materials, in the γ ray irradiated F co-doped fibers, we observed that the Ge(1) and the Ge(2) defects generation is unchanged, whereas it was enhanced for the E'Ge. In the various fibers, the comparison of the γ and X-ray induced concentrations of these kinds of Ge related defects indicates that the two irradiations induce similar effects regardless of the different employed dose rates and sources. Confocal microscopy luminescence results show that the starting content of the Germanium Lone Pair Center (GLPC) is neither strongly affected by the Ge content nor by the drawing conditions, and we consider the similarity of the GLPC content as key factor in determining many of the above reported similarities.

On the Anomalously Strong Dependence of the Acoustic Velocity of Alumina on Temperature in Aluminosilicate Glass Optical Fibers—Part I: Material Modeling and Experimental Validation

The thermo‐acoustic coefficient (TAC, or the change of acoustic velocity with a change in temperature) of the alumina (Al2O3) component in aluminosilicate core silica clad glass optical fibers is anomalously large. It has been speculated previously that this anomaly is not due to a large alumina TAC, but instead due to the thermal expansion mismatch between the aluminosilicate core glass and the pure silica cladding glass. In this new work, it is shown that the acoustic velocity of the aluminosilicate core glass changes much differently than that for a bulk aluminosilicate glass. In the high alumina content compositional range, it is found that the larger core‐region thermal expansion results in a net positive pressure imparted on the silica component in the core. As the acoustic velocity of silica has a strong negative dependence on any applied pressure, this offsets the bulk positive‐valued thermal response of silica. Utilizing a modified form of the Winkelmann–Schott additivity model, the effect of the thermal expansion mismatch between the core and clad glasses is incorporated, and the resultant TAC determined for alumina is fully consistent with data found in the literature for bulk alumina. The consideration and incorporation of the thermal expansion of the core and clad glasses adds another degree of freedom to the design of specialty optical fibers for distributed sensor applications. Complementary to this article, Part II describes an efficient computational route for determining selected physical properties of an amorphous analog to a given crystalline form whose physical properties are known.

Unrepeatered DP-QPSK Transmission Over 352.8 km SMF Using Random DFB Fiber Laser Amplification

Unrepeatered 100 Gbit/s per channel wave-division-multiplexed dual-polarization-QPSK transmission with random distributed feedback fiber laser-based Raman amplification using fiber Bragg grating is demonstrated. Transmission of 1.4 Tb/s ( $14 \times 100$ Gbit/s) was possible in 352.8 km link and 2.2 Tb/s ( $22 \times 100$ Gbit/s) was achieved in 327.6 km without employing remote optically pumped amplifier or speciality fibers.

Effect of heat treatment of optical fiber incorporated with Au nano-particles on surface plasmon resonance

To improve the sensitivity of the surface plasmon resonance (SPR) sensor based on the specialty optical fiber incorporated with Au nano-particles (NPs) in the cladding region, the effect of heat treatment (800 °C - 1000 °C) of the fiber on sensing capability of refractive index (n = 1.418 - 1.448) was investigated. The SPR appeared at a particular wavelength around 390 nm for the corresponding refractive indices regardless of the heat treatment temperature and the SPR wavelength increased with the increase of the index. The SPR sensitivity was found to increase with the increase of heat treatment temperature, 178 nm/RIU, 299 nm/RIU, and 945 nm/RIU at 800 °C, 900 °C, and 1000 °C for an hour, respectively. On the other hand, the SPR absorption intensity decreased with the increase of heat treatment temperature due to the increase of the propagation loss of the incident light and the SPR band became spread due to the increase of the size distribution of the Au NPs at the various refractive indices.

Viscose speciality fibres – bio-based fibres for filtration

Viscose fibres consist of cellulose and have the same advantageous health, security and environmental properties as natural cellulose fibres. However, viscose fibres are manufactured from natural wood pulp in a chemical process, in which natural variations of the raw material are levelled out. This article demonstrates that viscose speciality fibres are tailor-made cellulosic fibres for filter media manufacture and looks at potential future applications.

Ultra-thin and flexible endoscopy probe for optical coherence tomography based on stepwise transitional core fiber

We present an ultra-thin fiber-body endoscopy probe for optical coherence tomography (OCT) which is based on a stepwise transitional core (STC) fiber. In a minimalistic design, our probe was made of spliced specialty fibers that could be directly used for beam probing optics without using a lens. In our probe, the OCT light delivered through a single-mode fiber was efficiently expanded to a large mode field of 24 μm diameter for a low beam divergence. The size of our probe was 85 μm in the probe's diameter while operated in a 160-μm thick protective tubing. Through theoretical and experimental analyses, our probe was found to exhibit various attractive features in terms of compactness, flexibility and reliability along with its excellent fabrication simplicity.

Prickle and handle properties of fabrics produced from specialty animal fibers

Specialty animal fibers are commercially valuable since they significantly enhance the comfort properties of apparel products. As they help to create niche products, use of special animal fibers has increased significantly. There are many types of specialty fibers, such as cashmere, mohair, alpaca, and angora rabbit fibers, that are natural, ecological, and sustainable. Each of them has distinguishing properties and increases the added value of garments. In this work, five different specialty animal fibers and wool were sourced from four different countries. Yarns were spun using two different spinning systems. In the first method, to spin the yarns in a short staple spinning system, animal fibers were blended with viscose fibers. In the second method, to produce fabrics from 100% animal fibers, core yarn spinning system was used. Later, the yarns were knitted in a single jersey structure. After the production of all fabrics, handle properties such as surface friction, stiffness, and prickliness were tested by using both subjective and objective measurement techniques. To measure inherent fabric prickle, a new objective measurement technique was developed. Subjective and objective evaluation results highly correlate and it is pointed out that the new technique could be an alternative method to test fabric prickliness. Fabrics produced from silk, angora, and cashmere fibers are found to have the smoothest, softest, and least prickly surfaces among the other researched fibers.

Temperature characteristics of silicon core optical fiber Fabry-Perot interferometer.

Silicon core optical fiber expanded silicon photonics to specialty fiber platform. Although great challenges still exist for the fiber fabrication, the presence of semiconductor material has already given optical fiber new features and enormous possibilities for fiber-based devices and sensors. In this Letter, an all fiber silicon cavity Fabry-Perot interferometer was made by splicing silicon core silica cladding fiber with conventional single-mode silica fiber. The cavity shows high temperature sensitivity around 82pm/°C due to the larger thermo-optical coefficient of silicon material compared with that of silica material.

Development of PCR-based technique for detection of purity of Pashmina fiber from textile materials.

Pashmina fiber is one of major specialty animal fiber in India. The quality of Pashmina obtained from Changthangi and Chegu goats in India is very good. Due to restricted availability and high prices, adulteration of natural prized fibers is becoming a common practice by the manufacturers. Sheep wool is a cheap substitute, which is usually used for adulteration and false declaration of Pashmina-based products. Presently, there is lack of cost-effective and readily available methodology to identify the adulteration of Pashmina products from other similar looking substitutes like sheep wool. Polymerase chain reaction (PCR)-based detection method can be used to identify origin of animal fiber. Extraction of quality DNA from dyed and processed animal fiber and textile materials is a limiting factor in the development of such detection methods. In the present study, quality DNA was extracted from textile materials, and PCR-based technique using mitochondrial gene (12S rRNA) specific primers was developed for detection of the Pashmina in textile blends. This technique has been used for detection of the adulteration of the Pashmina products with sheep wool. The technique can detect adulteration level up to 10 % of sheep/goat fibers in textile blends.

Refractive index insensitive temperature sensor based on specialty triple-clad fiber.

A refractive index (RI) insensitive temperature sensor based on specialty triple-clad fiber (STCF) is proposed. Based on coupling mode theory, the STCF can be equivalent to a rod waveguide and two tube waveguides. Then the cladding mode resonance characteristic of STCF is analyzed by calculating different mode dispersion curves, which indicates that it works only on the mode resonance from core to the fluorine-doped silica cladding, and finally a resonance wavelength can be obtained. Two straightforward experiments are performed to prove its sensing properties. Experimental results show that it has sensitivities of 72.17 pm/°C at temperature range from 35°C~95°C with characteristics of insensitive to external RI in the range from 1.3450 to 1.4607. Thus, this proposed sensor can be used for solution temperature monitoring in real time.

Review of plasmonic fiber optic biochemical sensors: improving the limit of detection.

This paper presents a brief overview of the technologies used to implement surface plasmon resonance (SPR) effects into fiber-optic sensors for chemical and biochemical applications and a survey of results reported over the last ten years. The performance indicators that are relevant for such systems, such as refractometric sensitivity, operating wavelength, and figure of merit (FOM), are discussed and listed in table form. A list of experimental results with reported limits of detection (LOD) for proteins, toxins, viruses, DNA, bacteria, glucose, and various chemicals is also provided for the same time period. Configurations discussed include fiber-optic analogues of the Kretschmann–Raether prism SPR platforms, made from geometry-modified multimode and single-mode optical fibers (unclad, side-polished, tapered, and U-shaped), long period fiber gratings (LPFG), tilted fiber Bragg gratings (TFBG), and specialty fibers (plastic or polymer, microstructured, and photonic crystal fibers). Configurations involving the excitation of surface plasmon polaritons (SPP) on continuous thin metal layers as well as those involving localized SPR (LSPR) phenomena in nanoparticle metal coatings of gold, silver, and other metals at visible and near-infrared wavelengths are described and compared quantitatively. Graphical Artist rendering of light from a tilted fiber Bragg grating probing the cladding surface where a thin gold film and biofunctional layer are used to detects analytes

锥形三包层石英特种光纤折射率与温度传感器

锥形三包层石英特种光纤折射率与温度传感器

Instrumentation optical fibres for wave transformation, signal processing, sensors, and photonic functional components, manufactured at Białystok University of Technology in Dorosz Fibre Optics Laboratory

Abstract Tailored, specialty optical fibres, made of complex glasses, called collectively as a non-telecommunications or instrumentation family, serve for various optical wave transformations for particular functional purposes and optical signal processing, rather than for long distance lossless and dispersionless, undistorted transmission. Research work on these fibres started during the late seventies of the last century in ITME/Warsaw and in Białystok University of Technology at the Faculty of Electrical Engineering. The initiator of this research at Glass Works Białystok [39] and Białystok University of Technology [4] was, then a very young engineer, Jan Dorosz. Over 35 years of development of the technological team, under his skilful management, resulted in a top laboratory which today does research at the cutting edge of the photonics science. The Białystok Optical Fibre Technology Laboratory (OFTL) is now a pearl in the crown of his Alma Mater. The paper opens this special issue of the PAS Bulletin on Technical Sciences, devoted to professor Jan Dorosz, and shows some of the developments in the area of optical fibre photonics, which were carried out at his active laboratory.