Single Fiber Research Articles

Discharge splicing-free ultra-highly sensitive fiber-optic temperature sensor based on PDMS and the Vernier effect

A novel discharge splicing-free ultra-highly sensitive fiber-optic temperature sensor, based on polydimethylsiloxane (PMDS) and the Vernier effect, is constructed and experimentally validated. The sensor comprises single mode fiber (SMF), hollow core fiber (HCF), and PDMS. The Vernier effect is produced by the PDMS cavity and the mixed PDMS-air cavity during fabrication. By virtue of the Vernier effect and the temperature-sensitive material PDMS, this sensor shows an exceptionally high temperature sensitivity of −4.08658 nm/℃ while maintaining an outstanding linearity of 0.99972. The repeatability and stability have been demonstrated by subjecting the sensor to three cycles of heating and cooling, each with a 24-hour interval. Furthermore, experimental results indicate that the sensor exhibits excellent resistance to microvibrations and the interference occurs inside the structure, enabling its reliable operation in harsh environments without additional package. The miniature fiber temperature sensor is easily fabricated, highly sensitive, and demonstrates exceptional stability and repeatability, serving an ideal alternative for measuring temperature in challenging conditions.

Power Over Fiber and Analog Radio Over Fiber Simultaneous Transmission Over Long Distance in Single Mode, Multicore, and Hollow Core Fibers

AbstractIn this work, a novel study of the feasibility of shared Power over Fiber (PoF) and Fifth‐Generation (5G) New Radio (NR) Analog Radio over Fiber (ARoF) over long distance Hollow‐core Fibers (HCF) is presented. Comparative measurements between similar lengths of HCFs, Multicore (MCF) and Single Mode Fibers (SMF) are performed. A complete analysis on the Stimulated Raman Scattering (SRS)‐induced noise transfer from PoF to ARoF is tackled. Relative Intensity Noise (RIN) of ARoF signals is measured for all the optical fibers tested, observing no degradation in HCFs, neither on MCFs and significant deterioration in SMFs. A combination of PoF and 5G NR ARoF link in a single fiber is implemented, and 5G NR signals with different modulation formats are successfully transmitted through HCFs and MCFs without degradation, while SRS‐induced noise transfer in SMFs massively deteriorate them. PoF transmission efficiencies are also analyzed, achieving up to 9.9 % System Energy Efficiency (SEE) for a 3.1 km HCF, 0.9 % for a 11.1 km HCF and 1.5 %, 13.5 %, and 20.4 % in a 10 km MCF, a 9.8 km SMF and a 3.3 km SMF, respectively. The PoF signal is used to supply a Bluetooth Low‐Energy (BLE) load with a power consumption of 20 mW.

Investigation of Transmission and Reflection of Single Mode Fiber Bragg Grating

The use of Single Mode Fiber Bragg Grating (SMFBG) has been increasing in recent years due to its compact size, low cost, fast response and immunity to electromagnetic interference. It is commonly integrated into medical devices for long-distance light transmission and collection due to its high flexibility, low propagation loss, compatibility and tolerance to electromagnetic interference. SMFBG is a device made of thin glass material that is used as a medium for transmitting information in the form of light signals sourced from lasers or LEDs from one location to another. It consists of 3 main components, namely core with a certain grating, blanket (cladding) and jacket (coating). The advantage of optical fiber is that the data when transmitted is converted into light so as to reduce the risk of data damage. Other advantages include very small size, minimal interference with electromagnetic waves, resistance to temperature changes, attenuation when the transmission process is small enough, and large enough bandwidth. The orientation of this literature review is to understand the concept of optical fiber, the concept of reflection and refraction, and how light propagates in optical fiber.

CAS3D: 3D quantitative morphometry on Second Harmonic Generation image volumes from single skeletal muscle fibers

The CAS3D image processing method intuitively applies a combination of Fourier space and real space 3D analysis algorithms to volumetric images of single skeletal muscle fiber Myosin II Second Harmonic Generation (SHG) XYZ image data. Our developed tool automatically quantifies the myofibrillar orientation in muscle samples by determining the cosine angle sum of intensity gradients in 3D (CAS3D) while determining the mean sarcomere length (SL) and sample orientation. The expected CAS3D values could be reproduced from ideal artificial data sets. Applied random noise in artificial images lowers the detected CAS3D value, and for noise levels below 20%, the correlation can be approximated by a linear function with a slope of −0.006 CAS3D/noise%. The deviations in SL and orientation detection were determined on ideal and noisy artificial data sets and were statistically indistinguishable from 0 (null hypothesis t-test P > 0.1). The software was applied to a previously published data set of single skeletal muscle fiber volumetric SHG image data from a rat intensive care unit (ICU) model of ventilator-induced diaphragm dysfunction (VIDD) with treatment regimens involving the small anti-inflammatory molecules BGP-15, vamorolone, or prednisolone. Our method reliably reproduced the results of the previous work and improved the standard deviation of the cosine angle sum detection in all sample groups from a mean of 0.03 to 0.008. This improvement is achieved by applying analysis algorithms to the whole volumetric images in 3D in contrast to the previously common method of slice-wise XY analysis.

Penetration of oils into hair.

The objective of this work was to understand how triglyceride plant oils can deliver strength and softness benefits to hair by their penetration. These plant oils are complex mixtures of TAGs, so the initial studies performed were with pure TAGs and then these data compared to plant oils and their measured TAG compositions. LC-MS was used to identify the di and triglycerides in coconut oil, Camellia oleifera oil and safflower seed oil. Penetration of these plant oils and pure individual triglycerides was measured by a differential extraction method. Cross-sections of oils treated with 13C-labelled triolein were studied by NanoSIMS to visualize location of triglyceride inside hair. Fatigue strength was measured using constant stress to generate a survival distribution. Models of the lipid-rich cell membrane complex (CMC) were created with the equimolar ratio of 18-methyl-eicosanoic acid (MEAS), palmitic acid (C16:0) and oleic acid (C18:1). Penetration of the individual pure TAGs was confirmed for all chain lengths and degree of unsaturation tested with higher penetration for shorter chain lengths and unsaturated fatty acids. Detailed compositional analysis of selected plant oils showed a wide variety of TAGs and penetration was also demonstrated for these oils. NanoSIMS and modelling confirmed these TAGs are penetrating the lipid-rich CMC of hair and are interacting with the fatty acids that make up the CMC. All plant oils delivered a fatigue strength improvement by penetration into the CMC and it is proposed that these oils prevent formation and/or propagation of flaws in the CMC network that leads to breakage. Many plant oils with a wide range of triglyceride compositions can penetrate into hair and NanoSIMS data confirmed these oils partition into the lipid-rich cell membrane complex. Penetration studies of individual TAGs shown to be present in these oils confirmed TAGs of varying chain length can penetrate and there is a correlation between increased penetration efficacy and shorter chain lengths and presence of unsaturation in the fatty acid chains. All the oils studied delivered single fibre fatigue strength benefits.

Investigation on fiber fracture mechanism and milling force model of CF/PEEK by ultrasonic milling

Ultrasonic milling can achieve high machining efficiency and surface quality on CF/PEEK composites due to its advantages of low cutting force, high material removal rate, improved surface quality, long tool life, and eco-friendly machining technology. This method is widely used in many scenarios such as aerospace, navigation, and new types of weapons. However, the changes in fiber fracture mode and the effects of fiber friction caused by high-frequency ultrasonic vibration cannot be ignored. To study this, first, a fiber fracture model is constructed based on experiments to describe the fiber fracture mechanism. Then, the machined surface and subsurface are analyzed to establish the relationship between feed speed and fiber deformation depth. Increasing the feed can increase the fiber deformation depth by 3.17 times. Finally, an analysis of the single fiber fracture mechanics is carried out and a force model is created that considers the friction between the tool tip and the fiber during ultrasonic milling. The predictive force model, integrated with the fiber distribution, was validated against experimental results, showing a maximum force error of 5.722 %. This model effectively explains the fracture mechanism of CF/PEEK fibers during ultrasonic milling at the microscopic level.

Effects of hard and soft confinement on crystal polymorphism and crystal development in electrospun core‐sheath fibers

AbstractThis study employs coaxial electrospinning to fabricate core‐sheath fibers composed of crystalline poly(L‐lactide) (PLLA) in the core and amorphous polystyrene (PS) in the sheath. The fibers undergo cold crystallization at temperatures either below (hard confinement) or above (soft confinement) the glass transition temperature of PS. These conditions are employed to investigate the crystallization behavior of PLLA under multiple confinement types. The electrospinning of PLLA fibers results in the development of coexisting α‐ and α′‐form crystals. The coaxial electrospinning process enhances the extent of chain stretching of PLLA through the PS solution in the outer layer, thereby promoting the close packing of PLLA chains and facilitating the formation of α crystals. Crystallization within soft confinement enables PLLA chains to relax, leading to an increased population of α crystals; this phenomenon is not observed in electrospun single PLLA fibers. A comparison of the crystal parameters in core‐sheath and single PLLA fibers reveals that the crystallite size and the degree of crystallinity are considerably higher in unconfined single PLLA fibers than in confined core‐sheath fibers. The encapsulation of PLLA into the fiber core strongly inhibits the chain movement of PLLA, resulting in a decrease in PLLA crystallizability.

Raman spectroscopic stress mapping of single high modulus carbon fibre composite fragmentation in compression

Fragmentation of high modulus carbon fibres is relevant to the failure mechanisms of advanced polymer matrix composites in compression. In situ spatially-resolved Raman spectroscopy during the fragmentation of model single fibre composites is used to map local stress distributions during failure events. The characteristic graphitic band (the G band) located around 1580 cm−1 is associated with the in-plane carbon-carbon bonds; this band shifts its position, and can be calibrated, with the local axial stress in the fibre. The analysis maps the evolution of local stresses with increasing overall composite compression strain, identifying a series of critical events, including fibre fracture, interfacial debonding, and the formation of inter-fragment ‘wedges’. Fitting shear lag models provides interfacial shear strength values. Multiple failure maps of two examples of high modulus PAN carbon fibres (M46J and M55J) demonstrate the possibility of local fragment bending due to fragment end contact. A timeline of potential fragmentation events is proposed for carbon fibres undergoing compression.

Investigation of optimal mechanical and anticorrosive properties of silane coupling agents modified chopped basalt fiber reinforced waterborne epoxy coatings

A common technique for creating composite coatings with superior performance involves altering the surface of fillers to improve their ability to bond with the resin matrix. This enhances the overall mechanical strength and corrosion resistance of the coatings, addressing inherent weaknesses in the materials. It is essential to investigate how interfacial bonding affects composite coatings in order to maximize their mechanical and anticorrosive qualities. This study investigates the impact of activating and grafting various silane coupling agents (SCAs) on mechanical and anti-corrosion properties of chopped basalt fibers (CBFs) reinforced waterborne epoxy (WEP) coatings. SEM and FT-IR analyses confirm successful SCA grafting onto CBFs. Mechanical tests, electrochemical impedance spectroscopy (EIS), salt spray aging, and UV accelerated aging demonstrate significant enhancements in mechanical properties and corrosion resistance of CBF/WEP coatings. Finite element analysis (FEA) simulates stress distribution in single fiber models to assess deformation damage resistance. Results highlight the effectiveness of KH560 modification and a 5 wt% CBFs content in enhancing corrosion resistance and mechanical properties of the CBF/WEP composite coating.

A fiber-wireless integration approach in WDM-PON architecture, boosted with polarization multiplexing and optical frequency comb source

Abstract The paper discusses an optical frequency comb source (OMCG)-enabled hybrid single mode fiber (SMF) and free space optical (FSO) communication system (fiber-wireless) delivering a total capacity of 96 Gbps by incorporating polarization division multiplexing (PDM) in passive optical network (PON) architecture. For the accomplishment of PDM, three diverse states of polarization (SOPs) are explored such as 00, 450, and 900. Performance investigation of proposed system is conducted for assessing Q factor and BER by exploring the different modulation formats in proposed system such as modified duo-binary return to zero (MDRZ), return to zero (RZ), compressed spectrum RZ (CSRZ), and non-RZ (NRZ). Results revealed that presented design can cover 30 km SMF + 3.4 km FSO range by incorporating MDRZ due to its spectral efficient and dispersion tolerant properties.

Mechanical behavior and apparent stiffness of flax, hemp and nettle fibers under single fiber transverse compression tests

While plant fibers find extensive use across numerous applications, their transverse behavior and mechanical properties lack direct and fiber-scale characterization, posing a significant knowledge gap. This paper investigates, for the first time, the transverse behavior of flax, hemp and nettle fibers through Single Fiber Transverse Compression Tests (SFTCTs). Finite element analysis is used to study the influence of time-dependent and irreversible inelastic behavior on the fiber’s response and identify configurations fit for the identification of apparent elastic properties. SFTCTs are performed experimentally with a repeated progressive loading protocol using a custom micro-mechatronic setup. An apparent fiber transverse elastic modulus of 1 to 3 GPa is identified by inverse method for all tested fibers, demonstrating high fiber anisotropy. Important inelastic features are also observed on fiber behavior. Their origin is discussed with both material behavior and structural mechanisms such as lumen collapse, identified as the main potential causes.

400-Gbps Coherent Transmission of 100-Gbps QKD-Secured Data Stream Over 184-km of Standard Single Mode Fiber Through Three QKD Links and Two Trusted Nodes

400-Gbps Coherent Transmission of 100-Gbps QKD-Secured Data Stream Over 184-km of Standard Single Mode Fiber Through Three QKD Links and Two Trusted Nodes

Noise and fading reduction in a phase-OTDR system using a multi-strand optical fiber sensing cable

This paper introduces an innovative architecture, to the best of our knowledge, for a phase-OTDR sensing system, employing a multi-strand optical fiber cable as the sensing element. Within the cable, the fiber strands are interconnected to form a single serpentine-shaped fiber. The key advantage of this architecture lies in its ability to enhance the detection performance of a phase-OTDR system by reducing missing alarms caused by interference fading. Additionally, noise reduction can be achieved by aggregating the sub-traces corresponding to all fiber strands. To further enhance performance, we associate the use of a multi-pulse averaging method, which involves aggregating traces obtained using multiple probe pulses with varying temporal widths. The results obtained indicate that the performance of this architecture is closely related to the number of fiber strands and the number of probe pulses used. We expect that the proposed phase-OTDR architecture is particularly well-suited for effective distributed intrusion monitoring applications in short- to medium-range sensitive infrastructures where high security is paramount.

Chip-encoded high-security classical optical key distribution

Abstract The information security plays a significant role in both our daily life and national security. As the traditional algorithm-based secure key distribution (SKD) is challenged by the quantum computers, the optical physical-layer SKD has attracted great attentions such as quantum SKD, chaos SKD, and reciprocity-based SKD. However, the cost of quantum SKD is still unaffordable and the latter two classical SKDs are only reliable with some preshared information or under simple eavesdrop. So far, there still lacks a high-security and low-cost optical SKD scheme. In this paper, we propose and demonstrate a high-security chip-encoded classical optical SKD paradigm based on the reciprocity of incoherent matrix. The security of SKD is facilitated by the incoherence of input light, and it is the first time that the classical optical SKD is achieved with silicon photonic chips and commercial optical fiber link. Experimentally, we set up a chip-to-chip communication link and achieve key generation rate of 100 bit/s over a 40 km single mode fiber, with key error rate of only 1.89 %. Moreover, we demonstrate the key capacity expansion of the proposed scheme with four-channel wavelength division multiplexing. Our proposal paves the way for the low-cost, high-security, and miniaturized optical SKD.

Dispersion Behavior of a Droplet Impacting a Single Fiber.

The high-gravity reactor, known for its excellent mass transfer capability, plays a crucial role in the carbon capture process. The wire mesh packing serves as the core structure for enhancing mass transfer performance. Understanding the underlying dispersion mechanism requires a thorough exploration of the dynamics of droplet impact on a single fiber. This work aimed to numerically study the process of a droplet impacting a single fiber by applying the volume of fluid method. The effects of initial velocity (u0), initial diameter (D0), impact eccentric distance (e), and impact angle (θ) on the deformation evolution and dispersion characteristics of a droplet impacting a single fiber were systematically studied. Central or vertical impacts can be categorized into four main stages: splitting, merging, stretching, and breaking. Meanwhile, asynchronous breaking, sliding splitting, and oblique stages were observed during eccentric and nonvertical impacts. Subsequently, dimensionless time (t*) and the rate of increase of the gas-liquid interfacial area (η) were introduced to quantitatively analyze the dispersion characteristics postimpact. Increasing the initial velocity, reducing the droplet diameter, minimizing the impact eccentric distance, and maximizing the impact angle all contribute to enhanced dispersion performance. A correlation for the maximum increase rate of the gas-liquid interfacial area of the droplet was proposed, with errors less than ±15%. Finally, the deformation mechanism of droplet impact on a fiber was summarized by analyzing the influences of differential pressure inside and outside the liquid film, as well as gas vortices.

Dynamic Drop Penetration of Horizontally Oriented Fiber Arrays.

In this experimental study, we combine drop impact into porous media and onto a single fiber to study drop impact into fiber arrays inspired by mammalian fur coats. In our 3D-printed arrays, we vary the packing density, fiber alignment, strand cross-section, and wettability. Drops impact fibers fixed at both ends, penetrating over short periods of time by momentum and laterally spreading throughout the array. Using image analysis, we measure penetration depth and wetted width into the array. Impact Weber number and intrinsic porosity define penetration, retraction, and rebound regimes. On average, at an impact Weber number of ≈80, staggered fibers reduce penetration by 24% in hydrophilic fibers and 34% in hydrophobic fibers, and the penetration reduction percentage is expected to increase with increasing Weber number. Our results indicate that as density grows toward the density of mammalian pelts, penetration will reach a maximum value independent of drop impact velocity, thereby providing an effective rain barrier. Hydrophilicity at the densities we test, 50-150 strands/cm2, aids fiber array resistance to dynamic penetration by impacting drops through the promotion of lateral drop spreading and inhibition of drop fragmentation. Conversely, hydrophobic fibers best resist low-speed wicking. The fraction of a drop that infiltrates hydrophilic and hydrophobic fibers is nearly identical for a fixed Weber number because lateral spreading restricts the penetration depth into hydrophilic fibers but does not restrict mass infiltration. Above a critical Weber number, the entire drop mass penetrates fiber arrays regardless of strand wettability.

Design of an explicit crack bridging constitutive model for engineered cementitious composites using polyvinyl alcohol (PVA) or polyethylene (PE) fiber

This paper aims to establish an explicit crack bridging model that can link engineered cementitious composites (ECC) behavior from single fiber to single crack scale, which is great of designing ECC featuring pseudo tensile strain hardening and multiple cracks expanding by tailoring microstructure and materials selection. In this study, fiber bridging stress was divided into three parts including fiber bridging stress with no rupture, fiber debonding fracture stress, and fiber pullout fracture stress. Subsequently, the fundamental crack bridging model was emerged when fiber bridging stress with no rupture subtracted from the fiber rupture stress in debonding and pullout stage. Moreover, two-way pullout and Cook-Gordon effect were also considered to establish the complete model. It was found that the two-way pullout situation of polyvinyl alcohol (PVA) fiber has a significant influence on the crack opening width due to its slip hardening property, while the Cook-Gordon effect presents a faint crack width increment for PVA-ECC. However, the Cook-Gordon effect makes a significant contribution to the crack opening width of the composite produced by polyethylene (PE). This building intelligible model presents a better prediction for ECC through the comparison of experimental data or real average crack width in previous models, thus confirming the validity of this model.

Transmission of 10 Gbps C-band-signal-based Radio Over Fiber for Next Generation Communication Systems

Rapid development of 5G networks encourages researchers to improve the radio-over-fiber (RoF) technique in order to reach 10 Gbps data transmission rates, to increase bandwidth and range, while reducing latency and implementation cost. This paper evaluates an analog radio-over-fiber (ARoF) technique that is compatible with long-distance communication systems. We demonstrate a long distance transmission of a 28 GHz 64 QAM signal via a single mode fiber (SMF) after modulating it with the use of two parallel Mach-Zehnder modulators, without any optical amplifiers. The results show that our prototype solution is capable of transferring data over distances of up to 140 km, via SMF, with a 10 Gbps data rate. The error vector magnitude (EVM) was found to be 7.709%. The proposed system offers exceptional capabilities in terms of supporting high bitrates, while ensuring that EVM remains within the 3GPP limits. Compared to other works, the proposed solution proves to be superior in terms of performance, making it an ideal choice for next generation long-haul communication systems.

Biomechanics of annulus fibrosus: Elastic fiber simplification and degenerative impact on damage initiation and propagation

This study addresses three primary objectives related to lumbar intervertebral disc (IVD) biomechanics under ramping quasi-static loading conditions. First, we explore the conditions justifying the simplification of axisymmetric elastic fiber families into single fiber bundles through discretized strain energy functions. Simulations reveal that a concentration factor exceeding 10 allows for a consistent deviation below 10% between simplified and non-simplified responses. Second, we investigate the impact of elastic fibers on the physiological stiffness in IVDs, revealing minimal influence on biological motions but significant effects on degeneration. Lastly, we examine the initiation and progression of annulus fibrosus (AF) damage. Our findings confirm the validity of simplifying elastic fiber families and underscore the necessity of considering elastic fiber damage in biomechanical studies of AF tissues. Elastic fibers contribute to increased biaxial stretch stiffness, and their damage significantly affects the loading capacity of the inner AF. Additionally, degeneration significantly alters the susceptibility to damage in the AF, with specific regions exhibiting higher vulnerability. Damage tends to extend circumferentially and radially, emphasizing the regional variations in collagen and elastic fiber properties. This study offers useful insights for refining biomechanical models, paving the way for a more comprehensive understanding of IVD responses and potential clinical implications.

Green, simple, and rapid construction of coating on aramid fiber surfaces and their effects on the mechanical properties of aramid fiber/rubber composite interfaces

First, the surface of aramid fibers (AF) was etched using plasma to enhance the roughness of the AF. The coating was then formed on the surface of the AF by solution dip-coating using a polymerizable deep eutectic solvent (PDES) and in-situ UV cured for 10 s. The study examined the impact of varying etching times on the interfacial properties between AF and natural rubber (NR). The atomic force microscopy images showed that the surface roughness gradually increased with the increase of etching time, and the interphase width gradually increased. A modulus interfacial layer with a platform role was established between high-modulus aramid fibers and low-modulus rubber. And when the etching time was 4 s/cm, the H pull-out force increased by 193.51% compared to the original AF and reached 18.08 N of the maximum strength. Comprehensively comparing the single fiber tensile strength, composite tensile strength and composite fatigue resistance, the AF-reinforced NR composites can be optimized when the treatment time is 3 s/cm. In sum up, this method of constructing a coating on the AF surface by etching first will lead to a great improvement in the interfacial properties between AF and NR, this method enables simple, green and continuous construction of coating on AF surfaces, making them have great application prospects in the field of aviation tires.