Flat Fiber Research Articles

Optical fiber with varied flat chromatic dispersion

This paper investigates the design and properties of the conventional all-solid silica based flat dispersion specialty optical fiber. The design utilizes depressed-clad type of refractive index profile which allows for precise control of the optical fiber modal properties, particularly the chromatic dispersion. Specifically designing the dopants concentrations and depressed clad to core diameter ratio allows to obtain optical fibers with flat chromatic dispersion ranging from anomalous to normal dispersion regime. The regime and the values of chromatic dispersion in optical fibers is obtained through the change of the core diameter with the refractive index profile being the same in all optical fibers. The influence of the dopant choice on the mechanical and optical properties is shown using finite element method (FEM) studies. The study demonstrates that fluorine is a better candidate than boron for optical fiber designs that require precise chromatic dispersion characteristics. Six optical fibers were manufactured with the same refractive index profile differing with core radius. This allowed to obtain optical fibers that have chromatic dispersion in anomalous region (17.82 ps/(nm∙km) at 1.96 µm) for the fiber DCFDF1 and normal region (−115.14 ps/(nm∙km) at 1.57 µm) for the fiber DCFDF6.

Experimental Investigation of the Behavior of SlFCON Column under Eccentric Monotonic Load

Abstract This research delves into the performance of Slurry Infiltrated Fibrous Concrete (SIFCON) columns when subjected to eccentric monotonic loading, through the examination of twenty columns until their point of failure. The research addresses gaps in existing literature by examining the effects of various parameters, including fiber type, volume fraction, and eccentricity ratio, on SIFCON column performance. Results reveal significant correlations between the studied parameters and the structural behavior of SIFCON columns. The investigation shows how the ultimate load affect by the eccentricity ratio, for instance, the hook end steel fiber with a volume fraction of 6%, where the ultimate load decreased by a factor of 0.25 when the eccentricity ratio changed from 0.1 to 0.5. Furthermore, increasing the volume fraction of steel fibers significantly enhances the energy absorption of SIFCON columns. For instance, with the hook-end steel fiber and an eccentricity ratio of 0.3, the energy absorption increased by a factor of 2.76 when the volume fraction of steel fiber changed from 4% to 9%. The type of fibers used plays a pivotal role in the material behavior of SIFCON, with the straight micro fiber exhibiting an ultimate load 2.17 times greater than flat crimped steel fiber types when the volume fraction was 9% and the eccentricity ratio was 0.3. Finally, based on the experimental results, an interaction diagram has been established for three types of SIFCON: straight micro steel fiber with a volume fraction of 12%, hook end steel fiber with volume fractions of 6% and 4%.

Geometry-modulated all organic 3D printed smart PLA fibers for flextension amplified giant mechanical energy harvesting and Machine learning assisted pressure mapping

Piezoelectret sensors offer a promising avenue for harvesting abundant mechanical energy in the environment, providing a sustainable power solution for low-powered electronics. However, effectively harnessing large impact mechanical energy remains a challenge. In this study, we introduce a novel 3D cylindrical self-powered piezoelectret sensor capable of converting irregular axial impact forces into uniform radial pressures, enabling efficient large-scale impact mechanical energy harvesting. The cylindrical piezoelectret sensor, operating via a flextensional mechanism, was fabricated using 3D printed poly(lactic acid) (PLA) fibers as the piezoelectret layer and poly(3,4-ethylenedioxythiophene) (PEDOT)-coated PLA as the electrode layer. Our cylindrical sensor demonstrates the output voltage, and current of ∼ 11.4 V and 7.2 μA, representing remarkable improvement of 250 % and 160 % respectively, compared to flat fiber membrane device. Furthermore, we leverage IoT connectivity and machine learning techniques to utilize the fabricated robotic sensor for pressure mapping applications. Through machine learning algorithms, we achieve a remarkable accuracy of 100 % in character identification based on sensor data. This work highlights the potential of organic robotic sensors for efficient energy harvesting and intelligent pressure mapping applications, paving the way for the development of sustainable and adaptive sensor systems for various real-world scenarios.

Assessing the mechanical properties of biobased versus fossil-based ropes and their impact on the productivity and quality of mussel (Mytilus galloprovincialis) in longline aquaculture: Toward decarbonization

The expansion of offshore mussel aquaculture is intertwined with the rising demand for mussel grow-out ropes. Currently, these ropes are manufactured using fossil-fuel based or fossil-based plastics. In response to concerns about plastic pollution and sustainable aquaculture practices, biobased materials have emerged as more sustainable alternatives. Yet, the importance of the choice of raw materials, as well as the methods used in their production and sourcing, is key in determining the performance of materials in sea conditions within the context of aquaculture. This study evaluated the functionality of biobased ropes in terms of productivity and durability, comparing them to fossil-based counterparts during a one-year mussel culture in offshore conditions. Across one-year culture, noteworthy mussel losses were observed in the fossil-based (65%) ropes compared to the biobased B1 (53%) and B2 (18%) prototype ropes, B2 and B1 ropes yielding 85% and 23% more mussel (kg/ m rope) than the fossil-based ropes. Moreover, the higher correlations of shell length and body weight over time suggesting that biobased ropes may be more suitable substrates for mussel growth compared to fossil-based ropes. The structural distinction between the round and more uniform fine multifilaments in biobased ropes, as opposed to the clustered structure of flat fibres in fossil-based ropes, may have contributed to a more effective surface area for the initial attachment and growth of seeded mussels, avoiding subsequent losses. The use of biobased ropes contributed positively to the interplay between substrate structure, biofouling, and mussel attachment, which may be used for guiding further designs of aquaculture biobased gears. Despite seasonal variations, the final condition, proximate and fatty acid composition of mussel indicated their marketability and high nutritional quality. Higher shell length and mussel yields observed, indicating a potential for mussels cultivated on biobased ropes, especially in B2, to reach a higher market value. Regarding durability, linear density of biobased ropes remained unaltered after one-year offshore mussel culture. The biobased B2 rope prototype showed the highest ratio between the retention of mechanical properties (Load at Break and elongation) and the total mussel weight held for one year. The findings of this study validate the biobased B2 prototype as the most promising alternative to fossil-based ropes. It significantly boosted production yields of high-quality mussels while maintaining rope durability throughout one year in offshore culture. These results hold promise for reducing the reliance on fossil-based plastic ropes in mussel aquaculture, thereby contributing to decarbonization efforts.

Propulsion particle and potential application analysis based on fiber oriented laser propulsion micro-structures

Three kinds of fiber oriented laser propulsion micro-structures (tapered fiber, fiber-capillary, and flat fiber micro-structure) were proposed in this study. The directional of the shock wave generated at the tip of the micro-structure, which can realize the directional propulsion of the particles. The propulsion mechanism, power source, and motion effect of the particles based on the three kinds of propulsion micro-structures were investigated. To better understand the physical mechanism behind the experimental phenomena, physical model of micro-structures were established. The experimental and simulation results demonstrate that the oriented laser propulsion based on three kinds of fiber propulsion micro-structures was dominated by the shock wave ejection mechanism, which was caused by the high pressure of the shock wave. By analyzing the positions of characteristic peaks in the plasma spectra, it is proved that the driving force of particle motion derives from the shock wave formed by the expansion of air plasma. In the process of particle oriented propulsion, it is found that the motion effect of particles strongly depends on the propulsion micro-structure design, laser energy, particle size as well as gap distance d, and it is found that compared with the tapered fiber and flat fiber micro-structure oriented propulsion experiment, the motion effect of particles based on fiber-capillary micro-structure propulsion experiment is more obvious. In addition, based on the characteristic that the fiber oriented laser propulsion micro-structures can realize the directional propulsion of particles, and the micro-structure has shown potential application value in microinjection, laser fun billiard ball, and directional removal of contamination particles inside microsystems, providing theoretical support for later research.

Design of large core AS2S3 chalcogenide PCF pumped at all-normal and anomalous dispersion regimes for supercontinuum generation

We design and simulate a near-zero flat dispersion As2S3 photonic crystal fiber (PCF) with a circular shape to generate a broad and smooth supercontinuum (SC). A near-zero flattened dispersion in the all-normal dispersion PCF is maintained in the 4–6.2[Formula: see text]m wavelength range. A 6[Formula: see text]m hyperbolic pulse is injected into this fiber, producing a flat spectrum from 2.45 to 8.4[Formula: see text]m at a peak power of 5[Formula: see text]kW. The generated SC in anomalous dispersion PCF can cover multi-octaves by a pump laser with a 6500[Formula: see text]nm wavelength, 10[Formula: see text]kW of peak power, and a 90[Formula: see text]fs duration in 10[Formula: see text]cm of the proposed fiber structure. These results are achieved by optimizing the fiber structure through the core size. In general, the proposed structures could be used for broadband smooth low-cost SC generation.

Fabrication of multilevel metalenses using multiphoton lithography: from design to evaluation.

We present a procedure for the design of multilevel metalenses and their fabrication with multiphoton-based direct laser writing. This work pushes this fast and versatile fabrication technique to its limits in terms of achievable feature size dimensions for the creation of compact high-numerical aperture metalenses on flat substrates and optical fiber tips. We demonstrate the design of metalenses with various numerical apertures up to 0.96, and optimize the fabrication process towards nanostructure shape reproducibility. We perform optical characterization of the metalenses towards spot size, focusing efficiency, and optical functionality with a fiber beam collimation design, and compare their performance with refractive and diffractive counterparts fabricated with the same technology.

Shear Buckling Mode and Failure of Flat Fiber- Reinforced Specimens in the Axial Compression 2. Numerical Method, Experimental and Numerical Investigations of the Specimens with a [0]s Layup

Shear Buckling Mode and Failure of Flat Fiber- Reinforced Specimens in the Axial Compression 2. Numerical Method, Experimental and Numerical Investigations of the Specimens with a [0]s Layup

Random Raman Fiber Laser as a Liquid Refractive Index Sensor

In this paper, a new concept of forward-pumped random Raman fiber laser (RRFL)-based liquid refractive index sensing is proposed for the first time. For liquid refractive index sensing, the flat fiber end immersed in the liquid can act as the point reflector for generating random fiber lasing and also as the sensing head. Due to the high sensitivity of the output power of the RRFL to the reflectivity provided by the point reflector in the ultralow reflectivity regime, the proposed RRFL is capable of achieving liquid refractive index sensing by measuring the random lasing output power. We theoretically investigate the effects of the operating pump power and fiber length on the refractive index sensitivity for the proposed RRFL. As a proof-of-concept demonstration, we experimentally realize high-sensitivity half-open short-cavity RRFL-based liquid refractive index sensing with the maximum sensitivity and the sensing resolution of–39.88W/RIU and 2.5075×10−5 RIU, respectively. We also experimentally verify that the refractive index sensitivity can be enhanced with the shorter fiber length of the RRFL. This work extends the application of the random fiber laser as a new platform for highly-sensitive refractive index sensing in chemical, biomedical, and environmental monitoring applications, etc.

Experimental Investigation on the Mix Proportion of Fiber-Reinforced Ultrahigh-Strength Grouting Material

Concrete tends to develop cracks once damaged, and wide cracks specifically would affect the whole structure negatively. When used for repairing wide cracks, traditional cement-based grouting materials could no longer meet the demand for tensile strength. The paper aims to develop a high-performance grouting material for crack repair and further investigate its fluidity, and compressive strength, flexural strength, and splitting tensile strength after hardening. Based on the design of ultrahigh-performance concrete (UHPC), this grouting material consists of cement, sand, water, superplasticizer, expansion agent, silica fume, fly ash, and flat copper-plated steel fiber. The initial fluidity and 30-min fluidity of the grouting material decreased with the addition of fly ash, silica fume, and flat copper-plated steel fiber, among which the silica fume had the greatest influence on the fluidity, followed by fly ash and steel fiber. The optimal content of flat copper-plated steel fiber, fly ash, and silica fume was 2%, 10%, and 15%, respectively. Furthermore, the prediction model of compressive strength of grouting material was established. It indicated that cement grade, water-cement ratio, curing age, silica fume, fly ash, and flat copper-plated steel fiber and can be used for the mix proportion design of grouting materials.

Flatness enhancement of multi-wavelength Brillouin-Raman fiber laser with 10 GHz spacing utilizing Raman pump power distribution.

A simple high flat amplitude multi-wavelength Brillouin-Raman fibre laser (MBRFL) with 10 GHz spacing and excellent optical signal-to-noise ratio (OSNR) in C-Band spectral region is demonstrated. The laser consists of a linear cavity in which 12 km dispersion compensating fiber (DCF) in addition to 49 cm Bismuth-oxide Erbium doped fiber (Bi-EDF) are employed as a gain medium for amplification. The impact of Raman pump power distribution through changes in coupling ratio on amplitude flatness is carried out by comparing the peak power discrepancy between odd- and even-order Brillouin Stoke lines. This is the main property that allows the efficient controlling of gain propagation between lasing lines that is vital for Stokes flattening initiation and other output spectra characteristics. The attainment of MBRFL with outstanding OSNR necessitates the utilizing of Bi-EDF as a noise suppressor. By utilizing a 50/50 coupler, 354 identical channels together with uniform Brillouin Stokes linewidth within only 0.3-dB maximum power difference between adjacent channels is generated. The average OSNR and Stokes power are 28 dB and -5 dBm respectively when the RPP is set at 1300 mW. To date, this is the highest flatness 10 GHz spacing MBRFL with outstanding OSNR attained in MBRFL that incorporate only a single Raman pump unit.

Highly sensitive Fabry-Perot acoustic sensor based on optic fiber spherical end surface

This paper presents and experimentally validates a highly sensitive fiber-optic Fabry-Perot interferometer sound sensor based on a fiber-optic spherical structure. The Fabry-Perot interferometer comprises an aluminum foil diaphragm and a fused fiber-optic microsphere end face, both sealed in a structure made of a glass tube. An optical fiber microsphere structure is used for the first time in acoustic sensing. Based on the strong focusing capability of the microsphere, the high coupling efficiency to the reflected beam, and the extensive range of the focused convergent optical field formed, the focused convergent optical fields facilitate the sensing of an extensive range of motion or deformation of the cavity compared to the divergent optical field of a flat fiber end face, i.e., the acoustic signals at more minor sound pressures can also be well sensed, thus compared to a flat fiber end face fiber The acoustic sensor can monitor acoustic signals over a more extensive frequency range and a larger range of acoustic pressure variations, and the output voltage signal is of a larger amplitude at the same acoustic signal, which allows the monitoring of acoustic signals at acoustic frequencies within the hearing range of the human ear. Experimental results show that the sensor shows a flat frequency response in the range of 20 Hz–20 kHz, covering all frequency components of the human ear hearing range, and the signal-to-noise ratio of the proposed acoustic sensor in the range of 20 Hz–20 kHz is greater than that of the flat fiber end-surface based acoustic sensor and the reference electroacoustic sensor, especially The sensor has the advantages of good high sensitivity, excellent linearity, wide planar response range, and simple manufacturing process. It can potentially be used as a highly sensitive, high acoustic quality fiber optic microphone in practical applications.

Multi-Lens Array (MLA)-Assisted Power- Modulated Photothermal Therapy for Enhanced Cancer Treatment

Photothermal therapy (PTT) has been used as a non-invasive and effective anti-tumor treatment by localizing optical energy in the tissue. The aim of the current study was to investigate the efficacy and safety of PTT against tumor by applying multi-lens arrays (MLA) for having uniform micro-beam distributions and power modulation (MD) for sustaining constant treatment temperature in the tissue. A 1064 nm laser system delivered the equivalent energy (270 J) through two different manners (flat optical fiber; Flat and MLA) to a target under three different irradiation conditions: 1.5 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for 180 s, 3 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for 90 s and 3 W/cm2 for 60 s followed by 1.5 W/cm2 for 60 s (MD). In vivo tests demonstrated that MLA was able to expand a distribution of constant temperature (up to 40%) and the extent of thermal coagulation (up to two-fold) in the tumor than Flat. Irrespective of delivery method, MD maintained a constant temperature (around 60°C) for 60 s, compared to fixed power, resulting in insignificant tumor recurrence ten days after treatment. MLA-assisted PTT with MD could enhance a therapeutic capacity against the tumor tissue by covering a wide treatment area with larger coagulative necrosis and less thermal injury

Electrospun Fibrous Silica for Bone Tissue Engineering Applications.

The production of highly porous and three-dimensional (3D) scaffolds with biomimicking abilities has gained extensive attention in recent years for tissue engineering (TE) applications. Considering the attractive and versatile biomedical functionality of silica (SiO2) nanomaterials, we propose herein the development and validation of SiO2-based 3D scaffolds for TE. This is the first report on the development of fibrous silica architectures, using tetraethyl orthosilicate (TEOS) and polyvinyl alcohol (PVA) during the self-assembly electrospinning (ES) processing (a layer of flat fibers must first be created in self-assembly electrospinning before fiber stacks can develop on the fiber mat). The compositional and microstructural characteristics of obtained fibrous materials were evaluated by complementary techniques, in both the pre-ES aging period and post-ES calcination. Then, in vivo evaluation confirmed their possible use as bioactive scaffolds in bone TE.

On-demand heart valve manufacturing using focused rotary jet spinning

On-demand heart valve manufacturing using focused rotary jet spinning

Compact high-resolution FBG strain interrogator based on laser-written 3D scattering structure in flat optical fiber

We demonstrate a fiber Bragg grating (FBG) strain interrogator based on a scattering medium to generate stable and deterministic speckle patterns, calibrated with applied strain, which are highly dependent on the FBG back-reflection spectral components. The strong wavelength-dependency of speckle patterns was previously used for high resolution wavemeters where scattering effectively folds the optical path, but instability makes practical realization of such devices difficult. Here, a new approach is demonstrated by utilizing femtosecond laser-written scatterers inside flat optical fiber, to enhance mechanical stability. By inscribing 15 planes of pseudo-randomized nanovoids (714 times 500 voids per plane) as a 3D array in a 1 times 0.7 times 0.16 mm volume, the intrinsic stability and compactness of the device was improved. Operating as a wavemeter, it remained stable for at least 60 h with 45 pm resolution over the wavelength range of 1040–1056 nm. As a reflection mode FBG interrogator, after calibrating speckle patterns by applying tensile strain to the FBG, the device is capable of detecting microstrain changes in the range of 0–200 mu epsilon with a standard error of 4 mu epsilon, limited by the translation stage step size. All these characteristics make it an interesting technology for filling the niche of low-cost, high-resolution wavemeters and interrogators which offer the best available trade-off between resolution, compactness, price and stability.

Effects of extraction techniques on textile properties of William banana peduncle fibers

In this research work, the effect of extraction methods on the physical (morphology, density, length, apparent diameter, and color) and mechanical (tensile and bending KAWABATA) properties of the William banana peduncle fibers were examined. Among the methods used to carry out those tests, can be cited; the extraction tests using water retting (WR), dew retting (DR), and rolling by mechanical extraction (ME). The mechanical tests were carried out using TEXTECHNO Vibromat ME (measurement of the vibration frequency of the fiber), tensile test (MTS 20/M), and a Bending KAWABATA KES-FB2-SH test. To analyze the microstructure of the longitudinal plane of William banana peduncle, Scanning Electron Microscopy (SEM) mapping was used. The results showed that, water retting, gave a high yield (42.55%) compared to fibers extracted by rolling (23.40%). The different methods of extraction by retting lead to a reduction of about 35% in the apparent diameter of the fibers compared to the fibers obtained mechanically. When studying the colors of the surfaces of the fiber, the results presented the fact that the fibers extracted by rolling (ME) were darker than those retted in water or dew (WR and DR). However, the retted fibers were redder and yellower compared to the fibers passed through a rolling mill. SEM mapping was a result of strips of flat fiber bundles, followed by the brittle fracture surface regardless of the extraction method used. water retted fibres are longer than those extracted by rolling. There was a high uniformity index (UI) value for WR (70. 89%), which showed that these fiber bundles were more uniform in length compared to the two other methods (66.4% for DR and 64.28% for ME). The density of the William banana peduncle was not very sensitive to the extraction method. Significant differences were revealed for the specific breaking strength, initial modulus, and elongation at break depending on the extraction method. The Kawabata bending test showed the fact that fibers extracted by rolling were stiffer (1.63 mNmm2/tex2) compared to retting method fibers (0.51 mNmm2/tex2 for WR and 0.73 mNmm2/tex2 for DR). There is a possibility of using William banana fiber for textile applications in view of the tensile and bending properties obtained.

Analysis Method for Post-Impact Damage Development in Carbon Fiber Reinforced Laminate under Repeated Loading

In the current work, an analysis method for obtaining post-impact damage propagation under cyclic compressive load in flat carbon fiber reinforced plastic (CFRP) panels is presented. The solution for damage growth life is given based on the introduced hypothesis of reference damage mode (RDM). The critical size of damage for obtaining damage growth life was informed by the analysis of crack driving force versus damage size conducted using finite element analysis (FEA). The applicability of the damage tolerance principle for the case of compression–compression cyclic loading of the structural element containing impact damage is discussed and illustrated by the example. The results of using the introduced simplified approach to the calculation of characteristics of damage growth life suggest that the use of the slow-growth approach in composite structures is possible, though the necessity of obtaining the exact parameters of the damage growth rate equation with regard to the chosen crack driving force measure must be addressed.

Self‐assembly of plasmonic nanoparticles on optical fiber end face

AbstractDue to low losses, optical fibers are excellent optical waveguides, but manipulating the wavefront below the diffraction limit while keeping fabrication costs down is a significant challenge. Top‐down lithographic methods can create arbitrary nanostructures on the fiber end face to manipulate the wavefront. Still, this method requires a flat fiber end face, which can only be made using elaborate preparation processes. We present a facile coating method in which we transfer a hexagonally packed monolayer of gold nanoparticles onto an untreated fiber end face. Using a poly(N‐isopropylacrylamide) particle coating, we could transfer the free‐floating monolayer from a water‐air interface to the fiber end face. Our self‐assembly method enables plasmonic gratings on rough surfaces and objects with large aspect ratios, which have been challenging for existing nanofabrication methods. Using electromagnetic simulation, we demonstrate the performance and utility of the concept as a refractive index sensor in which we consider different lattice constants. Our simulations cover possible analyses by calculating the structure under air, water, and polymer environments. Thus, we study the potential applications of low‐cost fiber‐based sensors with low optical losses.

Experimental Study on the Impact Resistance of Steel Fiber Reinforced All-Lightweight Concrete Beams under Single and Hybrid Mixing Conditions

An impact action can cause local, or even overall, damage to structural components. This paper investigates the effect of flat and wavy steel fibers on the mechanical impact resistance of all-lightweight concrete beams under single and mixed conditions. Four all-lightweight concrete beams were subjected to drop hammer impact tests. From the failure mode, local shear-type damage occurred at the midspan of the all-lightweight concrete beams, with mainly shear cracks. The steel fiber has an inhibitory effect on the generation and development of cracks and improves the phenomenon of concrete crushing and spalling after the impact of the beam. Different mixing methods will have different effects on the crack-inhibition effect of steel fiber. The mixed addition of steel fiber has a more prominent effect on crack-development inhibition, making the cracks finer. Under the conditions of adding the flat steel fibers alone, the wavy steel fibers alone, and the mixed addition of steel fibers, the peak displacement at the midspan was reduced by 14.29%, 22.86%, and 37.14%, respectively; in comparison, residual displacement was reduced by 18.18%, 50.91%, and 54.55%, and the peak impact force was increased by 6.98%, −2.62%, and 1.89%. In addition, the stiffness loss of the steel fiber-added specimens is slight, which can have a higher impact response when the drop hammer falls. The results show that the addition methods of the steel fibers have different effects on the improvement of the impact resistance of the all-lightweight concrete beams, and the mixed addition has a better effect than the single addition.