Fiber Fusion Research Articles

Fiber-to-Chip Packaging With Robust Fiber Fusion Splicing for Low-Temperature Applications

Fiber-to-Chip Packaging With Robust Fiber Fusion Splicing for Low-Temperature Applications

Both rapid hyperplasia and hypertrophy promoted skeletal muscle growth in mandarin fish Siniperca chuatsi, compared to big-eye mandarin fish Siniperca kneri

As important cultured fishes in China, mandarin fish, Siniperca chuatsi and big-eye mandarin fish, Siniperca kneri share similar external morphology and genomes, but have significant differences in growth rates. In this study, we used 6 mph (month post hatching) mandarin fish and big-eye mandarin fish to compare differences in skeletal muscle growth over a one-month period, and use transcriptomes to explore the reasons for the growth differences. The results showed that the different value in number of muscle fibers (2.72 times), density (2.56 times), area (1.95 times) and diameter (2.73 times) of mandarin fish are significantly higher than that of big-eye mandarin fish (P<0.05). Hypertrophy (Contribution rate: 97.9%) is the dominant factor in big-eye mandarin fish, and both hypertrophy and hyperplasia (Contribution rate: 2.1%) were significantly different from mandarin fish (P<0.05). Transcriptome results showed that differential genes were enriched in proliferation of satellite cells, protein synthesis and degradation. Further analysis of the transcriptome results showed that the number of Pax7-positive cells per unit area of mandarin fish was 2.3 fold higher that of big-eye mandarin fish (P<0.05). Myod, pax3, pax7, and myf5 mRNA expression of mandarin fish were significantly higher than those of big-eye mandarin fish(P<0.05). In muscle fiber fusion, mef2, myog, and myomaker mRNA expression of mandarin fish were significantly higher than that of big-eye mandarin fish (P < 0.05). In protein deposits, the results showed that the muscle fiber area of mandarin fish was 2.85 times larger than that of big-eye mandarin fish by comparing the muscle fiber area with the same number of nuclei. Polr2a, mtorc1, 4e-bp1, s6, e1, murf, foxo3, atg5, beclin, and atg14 mRNA expression of mandarin fish were significantly higher than that of big-eye mandarin fish (P < 0.05), while eef2, eif2α, gcn2, eif2b, capn and cast of mandarin fish was significantly lower than that of big-eye mandarin fish (P < 0.05). This work verified that the skeletal muscle growth rate of mandarin fish is faster than that of big-eye mandarin fish. The greater number and higher activity of satellite cells of mandarin fish increased hyperplasia efficiency, and the faster fusion rate and protein precipitation rate increased hypertrophy efficiency. Both hyperplasia and hypertrophy contribute to faster skeletal muscle growth of mandarin fish than that of big-eye mandarin fish.

Mustn1 in Skeletal Muscle: A Novel Regulator?

Skeletal muscle is a complex organ essential for locomotion, posture, and metabolic health. This review explores our current knowledge of Mustn1, particularly in the development and function of skeletal muscle. Mustn1 expression originates from Pax7-positive satellite cells in skeletal muscle, peaks during around the third postnatal month, and is crucial for muscle fiber differentiation, fusion, growth, and regeneration. Clinically, Mustn1 expression is potentially linked to muscle-wasting conditions such as muscular dystrophies. Studies have illustrated that Mustn1 responds dynamically to injury and exercise. Notably, ablation of Mustn1 in skeletal muscle affects a broad spectrum of physiological aspects, including glucose metabolism, grip strength, gait, peak contractile strength, and myofiber composition. This review summarizes our current knowledge of Mustn1's role in skeletal muscle and proposes future research directions, with a goal of elucidating the molecular function of this regulatory gene.

Magnetic resonance imaging-based classification of the myodural bridge complex and its influencing factors

Cerebrospinal fluid (CSF) circulation is considered the third circulation of the human body. Recently, some scholars have proposed the myodural bridge (MDB) as a novel power source for CSF flow. Moreover, the suboccipital muscles can exert a driving force on the CSF via the MDB. This hypothesis is directly supported by head rotation and nodding movements, which can affect CSF circulation. The MDB has been validated as a normal structure in humans and mammals. In addition, the fusion of MDB fibers of different origins that act in concert with each other forms the MDB complex (MDBC). The MDBC may be associated with several CSF disorder-related neurological disorders in clinical practice. Therefore, the morphology of the MDBC and its influencing factors must be determined. In this study, T2-weighted imaging sagittal images of the cervical region were analyzed retrospectively in 1085 patients, and magnetic resonance imaging (MRI) typing of the MDBC was performed according to the imaging features of the MDBC in the posterior atlanto-occipital interspace (PAOiS) and posterior atlanto-axial interspace (PAAiS). The effects of age and age-related degenerative changes in the cervical spine on MRI staging of the MDBC were also determined. The results revealed four MRI types of the MDBC: type A (no MDBC hyposignal shadow connected to the dura mater in either the PAOiS or PAAiS), type B (MDBC hyposignal shadow connected to the dura mater in the PAOiS only), type C (MDBC hyposignal shadow connected to the dura mater in the PAAiS only), and type D (MDBC hyposignal shadow connected to the dura mater in both the PAOiS and PAAiS). The influencing factors for the MDBC typing were age (group), degree of intervertebral space stenosis, dorsal osteophytosis, and degenerative changes in the cervical spine (P < 0.05). With increasing age (10-year interval), the incidence of type B MDBC markedly decreased, whereas that of type A MDBC increased considerably. With the deepening of the degree of intervertebral space stenosis, the incidence of type C MDBC increased significantly, whereas that of type A MDBC decreased. In the presence of dorsal osteophytosis, the incidence of type C and D MDBCs significantly decreased, whereas that of type A increased. In the presence of protrusion of the intervertebral disc, the incidence of type B, C, and D MDBCs increased markedly, whereas that of type A MDBC decreased considerably, with cervical degenerative changes combined with spinal canal stenosis. Moreover, the incidence of both type C and D MDBCs increased, whereas that of type A MDBC decreased. Based on the MRI signal characteristics of the dural side of the MDBC, four types of the MDBC were identified. MDBC typing varies dynamically according to population distribution, depending on age and cervical degeneration (degree of intervertebral space stenosis, vertebral dorsal osteophytosis formation, simple protrusion of intervertebral disc, and cervical degeneration changes combined with spinal canal stenosis, except for the degree of protrusion of the intervertebral disc and the degree of spinal canal stenosis); however, it is not influenced by sex.

Differentiated Focal Plane Assisted Multi-core Fiber Fusion Splice Loss Evaluation

Differentiated Focal Plane Assisted Multi-core Fiber Fusion Splice Loss Evaluation

High sensitivity temperature and gas pressure sensor based on PDMS sealed tapered hollow-core fiber

We use hollow core fiber (HCF) and single mode fiber (SMF) fusion splicing to form a sensor with a “SMF-HCF-SMF” structure. To improve the sensitivity of the sensor, the HCF is tapered and stretched to a waist diameter of 10 μm. Then, in order to further improve the sensitivity of the sensor to temperature and pressure, as well as the mechanical strength of the sensor, we coated a layer of polydimethylsiloxane (PDMS) thin film on the surface of the tapered HCF. When light propagates in the sensor, an anti-resonant reflection optical waveguide (ARROW) mechanism is formed. Due to the excellent thermal sensitivity and elasticity of PDMS, the transmission spectrum of the sensor will significantly drift due to changes in environmental temperature and gas pressure, achieving temperature and pressure measurement. The experimental results show that the maximum temperature and gas pressure sensitivity of the sensor reach −3.2321 nm/℃ and −22.80 nm/MPa, respectively. In addition, the sensor also has good repeatability and stability, as well as short response time. It has certain application prospects in the field of high sensitivity temperature and gas pressure sensing measurement.

The intrinsic mode activation and evolution in fiber splicing based on 3D refractive index profile characterization

Fiber fusion splicing tremendously affects the modal stability, insertion loss and transmission quality of the optical fiber communication systems. Especially, in the few-mode fibers, a tiny dissatisfactory fiber splicing operation may lead to a big modal perturbation or unexpected mode coupling. In this paper, we propose a 3D refractive index profile visualization method to demonstrate the mode activation and evolution in fiber fusion splicing. A refractive index profile measuring instrument is established and applied to detect the 3D refractive index profile deformation caused by the fiber splicing. Then, based on the measured values of 3D refractive index profile, the mode activation is analyzed for fiber splicing between a single-mode fiber and a two-mode fiber with different core-offset distance. Results show that the mode begins to tremble with a core-offset of 4 μm and the high-order modes are effectively activated at the core-offset of 7 μm. The basic theoretical model and experiment results provide a profound support in almost all kinds of fiber splicing operation, mode interference construction and mode coupling modulation. Additionally, the method can be expanded to the research on fiber cleaving and bending.

Development of a Handheld Optical Fusion Splicer with a Wing Sleeve Optical Connector

FTTH (Fibre to the Home) uses a fusion splice field-assembled optical connector. The fusion splice field-assembled optical connector is connected and assembled using a generic fibre fusion splicer. However, general purpose fusion splicers make the device difficult to operate in the installation field because the fusion splicer is too large and heavy to handle. As a result, the fibre optic splice often breaks during the optical connector assembly process. This makes it difficult to apply fusion-spliced optical connectors in the FTTH field. To solve this problem, this paper proposes a fusion splicer for FTTH that can perform fusion splicing using a wing-type sleeve optical connector. The proposed fusion splicer, with a connection module with a lifting/lowering function, is implemented to connect and protect the wing-type sleeve field-assembled optical connector. In addition, by eliminating the tube heater used as a connection protection method in the existing fusion splicer, the power module is reduced. The developed fusion splicer was evaluated for assembly reliability through splice loss measurements and a comparison of assembling time with the existing fusion splicer.

Preventing fiber–fiber adhesion of lignin–cellulose precursors and carbon fibers with spin finish application

Abstract Adhesion of fibers within a spun tow, including carbon fibers and precursors, is undesirable as it may interrupt the manufacturing process and entail inferior fiber properties. In this work, softwood kraft lignin was used together with a dissolving pulp to spin carbon fiber precursors. Lignin–cellulose precursors have previously been found to be prone to fiber fusion, both post-spinning and during carbon fiber conversion. In this study, the efficiency of applying different kinds of spin finishes, with respect to rendering separable precursors and carbon fibers, has been investigated. It was found that applying a cationic surfactant, and to a similar extent a nonionic surfactant, resulted in well separated lignin–cellulose precursor tows. Furthermore, the fiber separability after carbon fiber conversion was evaluated, and notably, precursors treated with a silicone-based spin finish generated the most well-separated carbon fibers. The underlying mechanism of fiber fusion post-spinning and converted carbon fibers is discussed.

General and Reliable Azimuthal Alignment Algorithm for Low Loss Multicore Fiber Fusion Splicing

Multicore fiber is a promising spatial division multiplexing technology to increase the transmission bandwidth of optical fiber links in any given available spatial cross section. To connect multicore fibers, similar to single-core fibers, fusion splicing is an indispensable tool. Since multicore fibers cannot be circularly symmetric, precise transverse and azimuthal alignment is crucial to minimize the insertion loss penalty that would originate from even small offsets in the core locations of the two fibers to be spliced together. In this paper, a novel azimuthal alignment algorithm for multicore fiber splicing is presented. Since it is based on side-view images, it can also determine the twist rates of both fibers to be spliced and take these twist rates into account when calculating the optimum azimuthal alignment angle at the very ends of the two fibers. In the case of fibers with markers, i.e., fibers that are not rotationally symmetric, the relative and absolute polarities of the two fiber ends are computed as well. We present the formulation of the azimuthal alignment algorithm and demonstrate its stability and versatility for a wide range of fibers with vastly different geometries, core numbers and twist rates, including an offset single-core fiber. In the case of 4-core fibers with markers, we achieve average splice losses of less than 0.03 dB regardless of the polarity, which is a substantial advantage in terms of real-world applicability in the field. For a twisted 7-core fiber, we demonstrate an accurate twist rate detection with standard deviation < 1.4/m (turns per meter).

Fiber laser with intracavity parallel Mach-Zehnder interferometers towards Vernier refractive index sensing.

In this paper, dual-wavelength laser emission of an erbium-doped fiber laser (EDFL) with a tunable distinct wavelength selection of the simultaneously produced laser lines was achieved by applying a parallel comb filter configuration based on the optical Vernier effect. The intracavity inserted proposed comb filter consists of two parallel branches to generate the Vernier effect. Each branch is an in-line Mach-Zehnder interferometer (MZI) filter, which is composed of a polarization-maintaining fiber fusion spliced between single-mode fibers with sphere shapes at both ends. The tunability of the selected laser wavelength was realized by submerging the proposed filter in different sodium chloride/water mixtures. The proposed comb filter-based Vernier effect was used to independently achieve the selection of the dual-wavelength EDFL lines and for refractive index (RI) sensing applications. The in-line M Z I 1 and M Z I 2 structures show a wavelength shift sensitivity to RI variations of -88 and 79nm/RIU, respectively. Our proposed MZI structure presents a reliable, straightforward, and low-cost spectral comb filter for separate tunable dual-wavelength laser generation in the c-band region. Furthermore, the proposed filter structure-based Vernier effect presents a new perspective and method in the RI sensing application.

Improvement in fusion performance between G652.D fiber and Ultra-low-loss fiber by controlling discharge current of fusion splicer

Due to factors such as external environment, splicing tools and differences in the fiber material itself, there are still many problems with the fusion performance of different kinds of optical fibers hybrid splicing. Up to now, the theoretical studies and experimental results reported on the loss and strength of fusion joint under harsh conditions have been too few and incomplete. Therefore, we have investigated the key issues to be solved in fiber fusion process, and firstly analyzed thermal characteristics in melt region, comprising fiber dopants diffusion effect and fiber core expansion, and then discussed the effects of fusion current and fusion time on fusion temperature, splice loss and fusion strength. Besides, a calibration method to improve discharge current of fusion splicer is proposed and splice loss model and fusion strength model for different types of optical fibers are established. Furthermore, fiber fusion-splicing experiments have been conducted under adverse circumstances, obtaining a large amount of experimental data. The simulation results are basically consistent with the theoretical analysis. Ultimately, the method has been directly applied to the field fiber fusion engineering with good results.

A more than 20-year follow-up of pain and disability after anterior cervical decompression and fusion surgery for degenerative disc disease and comparisons between two surgical techniques

BackgroundFollow-ups more than 20 years after neck surgery are extremely rare. No previous randomized studies have investigated differences in pain and disability more than 20 years after ACDF surgery using different techniques. The purpose of this study was to describe pain and functioning more than 20 years after anterior cervical decompression and fusion surgery, and to compare outcomes between the Cloward Procedure and the carbon fiber fusion cage (CIFC).MethodsThis study is a 20 to 24-year follow-up of a randomized controlled trial. Questionnaires were sent to 64 individuals, at least 20 years after ACDF due to cervical radiculopathy. Fifty individuals (mean age 69, 60% women, 55% CIFC) completed questionnaires. Mean time since surgery was 22.4 years (range 20,5–24). Primary outcomes were neck pain and neck disability index (NDI). Secondary outcomes were frequency and intensity of neck and arm pain, headache, dizziness, self-efficacy, health related quality of life or global outcome. Clinically relevant improvements were defined as 30 mm decrease in pain and a decrease in disability of 20 percentage units. Between-group differences over time were analyzed with mixed design ANOVA and relationships between main outcomes and psychosocial factors were analyzed by Spearman´s rho.ResultsNeck pain and NDI score significantly improved over time (p < .001), with no group differences in primary or secondary outcomes. Eighty-eight per cent of participants experienced improvements or full recovery, 71% (pain) and 41% (NDI) had clinically relevant improvements. Pain and NDI were correlated with lower self-efficacy and quality of life.ConclusionThe results from this study do not support the idea that fusion technique affects long-term outcome of ACDF. Pain and disability improved substantially over time, irrespective of surgical technique. However, the majority of participants reported residual disability not to a negligible extent. Pain and disability were correlated to lower self-efficacy and quality of life.

A Method for Suppressing Error of Fiber Optic Current Transformer Caused by Temperature Based on λ/4 Wave Plate Fabricated With Polarization-Maintaining Photonic Crystal Fiber

The beat length of λ/4 wave plate of fiber optic current transformer (FOCT) will change with the temperature fluctuation of environment, which will result in additional phase error, reducing the accuracy of current measurement. In the paper, we presented a FOCT based on λ/4 wave plate fabricated with polarization maintaining photonic crystal fiber (PCF). Combined with error model caused by λ/4 wave plate in FOCT, we analyzed the specific mechanism of temperature influence on λ/4 wave plate. Aiming at the problem of fusing PCF to panda polarization maintaining fiber, we optimized the related parameters of fiber fusion splicer to reduce the fusion loss of the fiber. It was experimentally verified that the beat length of PCF is less sensitive to temperature than that to elliptical core polarization maintaining fiber. Finally, we measured current of FOCT utilizing two kinds of λ/4 wave plates in full temperature range from -40 °C to 70 °C. It was verified that it is insensitive to temperature for FOCT when utilizing PCF λ/4 wave plate, with the corresponding system current measurement accuracy 0.5S level.

Experimental demonstration of offset-induced sensitivity enhancement in SMS-based temperature and strain sensing

A simple, inexpensive, and high-sensitivity temperature and strain sensor based on a single-mode–multimode–single-mode (SMS) structure with core offset is developed and experimentally characterized. This sensor does not require specialty fibers and can be fabricated using a standard fiber fusion splicer. The dependencies of the temperature and strain sensitivities on the core-offset amplitudes at the input and output single-mode/multimode fiber boundaries are investigated. The results indicate that the maximum temperature and strain sensitivities are two times and eight times higher than those of the standard SMS structure, respectively. The limit of the sensitivity enhancement by core offset is also revealed.

Intrinsically Healable Fabrics

AbstractWearable electronics with healability have been extensively researched recently. To provide wearing comfort, fabrics are often adopted as the base materials. Intrinsic healability, however, is challenging for fabrics because of the inability to retain the fibrous morphologies. Herein, an unprecedented strategy is presented for producing electrospun fabrics that are intrinsically healable by carefully balancing the crystalline structural support and healing ability. Fluorocarbon polymers with different crystallinities are mixed with ionic liquids to form ionogels, which are spun into fabrics using a unique wet electrospinning apparatus. Importantly, the introduction of the crystalline domains prevents the fusion of the electrospun fibers; even after 1 year, no significant morphological change is observed. The nonwoven fabrics are not only stretchable and waterproof but also intrinsically healable. The ion–dipole interactions between the polar copolymers and ionic liquids provide the reversible physical crosslinking essential to the healing capability. When damaged, the fabrics can be overlapped and healed after applying pressure. Moreover, the fabrics demonstrate healability underwater. Healable sensing devices, pressure, and tensile sensors are also designed by printing ion‐conductive gels as electrodes. Both devices show good stability before and after healing. This work demonstrates the first example of intrinsically healable electrospun fabrics, which are promising for fabric‐based wearable electronics and smart clothing.

Melt Electrowriting of Liquid Crystal Elastomer Scaffolds with Programmed Mechanical Response.

Recently, significant advances have been achieved to precisely program the response of liquid crystal elastomers (LCEs) through extrusion-based additive manufacturing techniques; however, important challenges remain, especially when well-defined scaffolds based on ultrafine fibers are required. Here the melt electrowriting of reactive liquid crystalline inks, leading, after ultraviolet-light-induced crosslinking, to digitally positioned uniform LCE fibers with diameters ranging from hundreds of nanometers to tens of micrometers is presented, whichishardly accessible with conventional extrusion-based printing techniques. The electrowriting process induces the preferential alignment of the mesogens parallel to the fiber's axis. Such an alignment, defined by the printing path, determines the mechanical response of the crosslinked material upon stimulation. This manufacturing platform allows the preparation of open square lattice scaffolds with ultrafine fibers (afew micrometers in diameter), periods as small as 90µm, and well-defined morphology. Additionally, the combination of accurate fiber stacking (up to 50 layers) and fiber fusion between layers leads to unprecedented microstructures composed of high-aspect-ratio LCE thin walls. The possibility of digitally controlling the printing of fibers allows the preparation complex fiber-based scaffolds with programmed and reversible shape-morphing, thus opening new avenues to prepare miniaturized actuators and smart structures for soft robotics and biomedical applications.

Wavelength Modulated Anti-Resonant Fiber-Optic Microfluidic Device Based on SMF-HCTF-SMF Structure

A wavelength modulated microfluidic device based on hollow core tube fiber (HCTF) is proposed, the modal dispersion and field distributions of the liquid-filled HCTF are analyzed and simulated based on the anti-resonant mechanism, and refractive index and temperature sensing performances are demonstrated. The device is formed by the single mode fiber-HCTF-single mode fiber structure, and there are two micro-slots at the fiber fusion joints for liquid flow through the HCTF. Comparative experiments show that the device can be immersed in liquid environments, which is difficult for the structure without micro-slots. Various devices with different HCTF inner diameters and lengths are fabricated, according to the anti-resonant mechanism, the non-transmission wavelength position, free spectrum range, and spatial frequency of the spectrum are discussed. Besides, the sensing performances of the microfluidic device with different structural parameters are also tested and compared, the experimental results are consistent with the theoretical analysis. This comparative study of the HCTF-based microfluidic element is instructive for the investigation of other kinds of anti-resonant structures. Moreover, the proposed microfluidic device is a promising biochemical sensor with a compact structure, high reliability, and ultra-sensitivity.

Fusion splicing of hollow-core to standard single-mode fibers using a gradient-index bridge fiber

High-performance interconnection between hollow-core fiber and conventional solid-core fiber is of great significance for a lot of promising applications of hollow-core fibers. The current problems for high-performance hollow-core fiber/solid-core fiber interconnection mainly involve mode field mismatch of the two fibers and the complex splicing process. Subject of study. We study fusion splicing of anti-resonant hollow-core fiber with low loss (0.52 dB) and conventional single-mode fiber using a convenient graded-index bridge fiber. Purpose of the work. We aim to eliminate the mode field diameter mismatch between anti-resonant hollow-core fiber and single-mode fiber and simplify the mode field diameter adaptation method and process. Method. We employ a convenient graded-index bridge fiber approach, where a gradient index fiber is first spliced with the single-mode fiber, and the mode interference within the graded-index bridge fiber causes periodic enlargement and shrinkage of the mode field diameter. By precise cutting of the graded-index bridge fiber, the mode field diameter can be well controlled and made approximately equal to the mode field diameter of the anti-resonant hollow-core fiber. After mode field diameter adaptation, an optimized arc discharge fusion splicing procedure is applied for the anti-resonant hollow-core fiber/single-mode fiber fusion splicing. Main results. A fusion splicing loss of about 0.52 dB is achieved, which involves nearly 0.42 dB mode-field-diameter-mismatch-induced loss and about 0.1 dB fusion splicing loss that is caused by the deformation of the anti-resonant hollow-core fiber. Practical significance. The developed approach is convenient and cost-effective, which can benefit a lot of applications of anti-resonant hollow-core fibers in future telecommunications, fiber gas lasers as well as fiber-optic sensing.

Electrospinning of Softwood Organosolv Lignin without Polymer Addition

Due to its nature and structure, lignin is a very difficult polymer to electrospin without any additives as only a few studies reported on the successful electrospinning of lignins in general and even more limited for softwood lignins to date. This paper highlights the possibility to use softwood organosolv lignin as a precursor for fiber electrospinning without any polymer addition. We have successfully electrospun pure organosolv softwood lignin into uniform, bead-free fibers. A concentration of 57 wt % of lignin in dimethyl formamide was determined as optimal, while other processing parameters (voltage, needle–collector distance, flow rate, and humidity) were studied to improve the fiber uniformity. We also studied the effects of minimum FeCl3 addition and demonstrated its efficiency in improving the processability. Thus, the addition of 2 wt % FeCl3 allowed decreasing the minimum fiber diameter from 400 to 200 nm. The addition of FeCl3 also resolved the problem of fiber fusion on the collector, and it also allowed increasing the glass transition temperature of lignin fibers. These results open a way to new applications of lignin, such as 100% biosourced carbon fiber since no petroleum-sourced molecules were used in this study.