Narrow Fiber Research Articles

Potential of pulp production from whole-tree wood of Betula platyphylla Roth. based on wood characteristics

To ascertain the possibility of using branchwood, trunkwood, and rootwood of Betula platyphylla Roth. in papermaking, this study investigated tissue proportion, fiber features, and major chemical components in whole-tree wood of the tree species. Analysis of variance (ANOVA) indicated that the rootwood had a significantly lower density and vessel proportion, higher ray proportion, wider lumen, and thicker wall of fiber than the trunkwood and branchwood (p <0.05). The branchwood had a significantly shorter fiber and smaller length/width than the trunkwood and rootwood (p <0.05). The trunkwood had significantly longer and narrower fibers with thinner wall and higher cellulose, but lower hemicelluloses than the branchwood and rootwood (p <0.05). The study concluded that the trunkwood of B. platyphylla was suitable for producing good paper, while the branchwood and rootwood met the basic requirements of papermaking and could be used to produce low-grade paper.

3.7 kW monolithic narrow linewidth single mode fiber laser through simultaneously suppressing nonlinear effects and mode instability.

In this paper, we report a 3.7 kW all fiber narrow linewidth single mode fiber laser. The full width at half-maximum is about 0.30 nm, and the beam quality is Mx2=1.358, My2=1.202 at maximum output power. The laser is achieved by simultaneously suppressing nonlinear effects and mode instability (MI). Different seeds are injected into the main amplifier to study stimulated Raman scattering (SRS) effect. The results show that the phase modulated single frequency seed is benefit to suppress the SRS effect. For the phase modulated single frequency seed, inserting a filter in preamplifier will suppress amplified spontaneous emission (ASE) and decrease the backward power. By optimizing the coiling of active fiber, the MI effect is suppressed.

Investigation of narrow band random fiber ring laser based on random phase-shift Bragg grating

Abstract A random fiber laser based on a 25 mm long random phase-shift fiber Bragg grating with a ring cavity is experimentally demonstrated in this paper. The random phase-shift grating is fabricated with the beam-scanning method in a single-mode fiber. The random feedback and light localization are achieved by introducing 20 phase-shift points with random amplitudes along the grating length. A narrow band single-wavelength random fiber laser with the 3 dB bandwidth of 0.44 pm is realized with a 980 nm laser pumping at 130 mW. The optical signal-to-noise ratio up to 55 dB is obtained at the same pump power. The pump threshold is only 21.8 mW. The number of emitted wavelengths is changeable by adjusting the pump power. The lasing wavelength near 1549.96 nm presents a maximum fluctuation range of only 1.1 pm over time. With the random grating exposed to water, the mode competition is suppressed and the laser can be operated at more stable single-wavelength mode.

Random Bragg-gratings-based narrow linewidth random fiber laser with a π-phase-shifted FBG

A new structure of short-cavity random fiber laser (RFL) with narrow linewidth lasing is proposed. A π-phase-shifted fiber Bragg grating (FBG) loop mirror was used in the RFL for spectral filtering and to suppress multi-mode oscillation due to the narrow transmission window. The random feedback of the RFL was implemented by a randomly dispersed weak reflection FBG array. The high gain of the erbium-doped fiber and a half-open cavity design results in a low lasing threshold. The linewidth of the laser was 225 Hz with 58 dB side-mode-suppression ratio. The laser threshold was 4.5 mW, and the optical signal-to-noise ratio was up to 63 dB.

Fibre morphological variations of some Nigerian guinea savannah timber species

Fibre morphology of some Nigerian tropical timber species were evaluated to determine their potentials as suitable source of raw material for pulp and paper making. The fibre dimension of the species showed that Syzygium guineense had the longest fibre length (2.0 mm) followed by Anogeissus leiocarpa (1.75 mm) while Albizia zygia had the shortest fibre length of 1.05 mm. Irvingia gabonensis had the largest fibre diameter while Vernonia colorata had the smallest. Vitellaria paradoxa had the widest lumen of 8.87µm while Irvingia gabonensis had the smallest lumen and thickest (6.87µm) cell wall while Vernonia colorata had the thinnest (4.40µm). Albizia zygia had the most slender fibres while Vitellaria paradoxa had the most rigid fibres. All the species had narrow fibre lumens and the cell walls were thick, which may have given poor results to the pulp made from them. The results of the ANOVA showed that there was high significant variation in all the fibre dimensions and the derived values of the species. DMR test showed that no statistical difference existed in the fibre length of Isoberlina doka, Khaya ivorensis and Albizia zygia. However, Vernonia colorata, Irvingia gabonensis and Vitellaria paradoxa had similar fibre length as well as Afzelia africana and Lannea welwitchii. All the species passed the Runkel Ratio 0.55 for an acceptable value for paper making. All the fibres were elastic except Vitellaria paradoxa and Anogeissus leiocarpa.

Stem anatomy at various developmental stages of secondary growth in Turbina corymbosa (Convolvulaceae)

Background – Population growth of lianas in the tropical forest is credited to their ability of CO2 sequestration and efficiency of the narrow stems to supply water required for the amount of foliage it bears. Turbina corymbosa (L.) Raf. (Convolvulaceae Juss.) is one of the fast-growing invasive species of scrambling woody lianas. It covers trees entirely within a short period to compete with above-ground resources (particularly sunlight). However, no information is available on how it manages to cope up with an increasing demand of water supply and mineral nutrients. What are the structural and developmental patterns adapted by this species to expand the stem diameter for efficient supply of below-ground resources? Therefore, our aim was to investigate the secondary growth patterns and structure of secondary xylem and phloem in T. corymbosa.Methods – Several samples of the stem with various diameters were studied using a histological method. Morphological and anatomical analyses were carried out using light microscopy.Key results – With the initiation of secondary growth, stems lose their circular outline rapidly due to unequal deposition of secondary xylem and formation of successive cambia. New successive cambia initiate from parenchymatous cells as small crescent-shaped fragments on asymmetric/opposite sides and result in a different stem conformation. Though several segments of successive cambia are formed, very few stem samples form complete cambium rings. The secondary xylem formed by successive cambia is diffuse porous with indistinct growth rings and is composed of both wide and narrow (fibriform) vessels, tracheids, fibres, axial and ray parenchyma cells. The secondary phloem consists of sieve tube elements, companion cells, axial and ray parenchyma cells. In fully grown plants, cambial action (internal cambium) occurrs between the intraxylary phloem and protoxylem and produces secondary xylem and phloem near the pith region.Conclusion – Structural alterations and unequal deposition of conducting elements, occurrence of intraxylary phloem and flattening of the stem are suggested to facilitate rapid growth of the plants by providing required minerals and nutrients. Internal cambium formed at the periphery of the pith is bidirectional and produces secondary xylem externally and intraxylary phloem internally. Continued development of intraxylary phloem from the internal cambium provides an additional path for rapid and safe translocation of photosynthates.

Narrow core standard single mode fiber for supercontinuum generation from graphene-based mode-locked pulses

Abstract In this work, a supercontinuum (SC) source is proposed and demonstrated using a highly-doped, 2 m long zirconia-erbium doped fiber (Zr-EDF) with a dopant concentration of 3800 ppm/wt and a narrow core 100 m long single-mode-fiber (SMF). A graphene based saturable absorber (SA) is used as a passive mode-locker, generating pulses with an average output power, pulse energy and peak power of ∼0.9 mW, ∼69.8 pJ and ∼83 W respectively and a repetition rate of 12.9 MHz. This is then amplified using a 140 mW amplifier, giving an output power, pulse energy and peak power of ∼75.0 mW, 5.8 nJ and ∼6.76 kW respectively and injected into a 100 m long SMF, to generate an SC output which spans from 1450 to more than 1700 nm, with a pulse width at its full-width-at-half-maximum (FWHM) of 120 fs, 7 times lower than the 840 fs FWHM width of the pulses from the fiber laser. The narrow core SMF performs comparably to longer lengths of standard SMF-28 fibers.

Main Characteristics of Underexploited Amazonian Palm Fibers for Using as Potential Reinforcing Materials

This study aimed to present the morphological, chemical, structural, thermal, and tensile properties of three Amazonian palm fibers (Leopoldinia piassaba—PIASSAVA, Desmoncus polyacanthos—JACITARA, and Astrocaryum sp.—TUCUM) and their inner (INN) and outer (OUT) portions, in order to provide support for possible use of these fibers as reinforcement in composites. TUCUM and TUCUM OUT presented the narrower fibers and lower lumen diameters, while JACITARA INN and OUT presented the wider fibers and higher lumen diameters. PIASSAVA and TUCUM INN were the shorter fibers, while JACITARA INN and OUT were the longer. TUCUM fibers presented the higher aspect ratio, wall fraction (WF), and coefficient of rigidity (CR). PIASSAVA fibers contain relatively higher lignin and extractive contents, which led to lower crystallinity index (CI), lower tensile strength (TS), lower modulus of elasticity (E), and higher elongation at break (EB) than others. JACITARA OUT fibers presented higher CI, thermal stability, and mechanical properties than JACITARA INN. TUCUM fibers presented the higher content of cellulose, and the higher values of TS and E, as also corroborated by their higher CI and thermal stability in relation to their counterparts. TUCUM INN exhibited more interesting characteristics (such as higher CI, thermal stability, and mechanical properties) than TUCUM OUT. The experimental results in the present work contribute to the widespread use of the different portions of these underexploited Amazonian palm fibers as a source of raw materials that may be used to engineer composites and new materials for a wide range of applications.

Antimicrobial Membranes of Bio-Based PA 11 and HNTs Filled with Lysozyme Obtained by an Electrospinning Process.

Bio-based membranes were obtained using Polyamide 11 (PA11) from renewable sources and a nano-hybrid composed of halloysite nanotubes (HNTs) filled with lysozyme (50 wt % of lysozyme), as a natural antimicrobial molecule. Composites were prepared using an electrospinning process, varying the nano-hybrid loading (i.e., 1.0, 2.5, 5.0 wt %). The morphology of the membranes was investigated through SEM analysis and there was found to be a narrow average fiber diameter (0.3–0.5 μm). The mechanical properties were analyzed and correlated to the nano-hybrid content. Controlled release of lysozyme was followed using UV spectrophotometry and the release kinetics were found to be dependent on HNTs–lysozyme loading. The experimental results were analyzed by a modified Gallagher–Corrigan model. The application of the produced membranes, as bio-based pads, for extending the shelf life of chicken slices has been tested and evaluated.

Single-longitudinal-mode, narrow bandwidth double-ring fiber laser stabilized by an efficiently taper-coupled high roundness microsphere resonator

Abstract This paper proposes and demonstrates a single-longitudinal-mode, narrow bandwidth fiber laser, using an ultra-high roundness microsphere resonator (MSR) with a stabilized package as the single-longitudinal-mode selector inside a double-ring fiber cavity. By improving the heating technology and surface cleaning process, MSR with high Q factor are obtained. With the optimized coupling condition, light polarization state and fiber taper diameter, we achieve whispering gallery mode (WGM) spectra with a high extinction ratio of 23 dB, coupling efficiency of 99.5%, a 3 dB bandwidth of 1 pm and a side-mode-suppression-ratio of 14.5 dB. The proposed fiber laser produces single-longitudinal-mode laser output with a 20-dB frequency linewidth of about 340 kHz, a signal-to-background ratio of 54 dB and a high long-term stability without mode-hopping, which is potential for optical communication and sensing applications.

Development of a 2 μm Tm-doped fiber laser for hyperspectral absorption spectroscopy applications

The hyperspectral absorption spectroscopy is attracting more and more attention as this technique enables continuous wavelength sweep over a whole absorption band, rather than one or several discrete absorption lines. Owing to the H2O possesses much stronger and more abundant absorption lines in the 2μm region, this work develop a widely tunable, narrow linewidth Tm-doped fiber laser around 1.87μm for the application of combustion diagnostics. The laser wavelength tuning range is designed from 1850 nm to 1890 nm to overlap the strong absorption band of H2O, and the laser linewidth is further narrowed to 0.04 nm by a fiber saturable absorber. With this laser system, demonstration experiments are implemented for the continuous detection of H2O absorption lines. Detailed absorption peaks of H2O from 1866 nm to 1879 nm are detected and well-resolved. The measured absorption spectrum agree well with the theoretical computation derived from HITRAN2012 database quantitatively, verifying this laser system ready for hyperspectral absorption applications.

Thermal degradation of Polylactide/Poly(ethylene glycol) fibers and composite fibers involving organoclay

Abstract In this study, electrospun fibers of melt blended poly(lactic acid) and poly(ethylene glycol), (PLA)-PEG blends involving 10, 15 and 20 wt% PEG and their corresponding composites with organically modified montmorillonite, Cloisite 30B were prepared and characterized by x-ray diffraction, differential scanning calorimetry, thermogravimetry and direct pyrolysis mass spectrometry techniques. The narrower fiber diameters observed for the PLA-PEG fibers involving organoclay compared to the corresponding neat fibers were associated with the presence of quaternary ammonium salt as organic modifier increasing electrical conductivity. Strong evidence for phase separation during the electrospinning process was detected for PLA-PEG fibers. On the other hand, for PLA-PEG composite fibers, as a consequence of the diffusion of both PLA and PEG chains from the bulk polymer into the galleries between the silicate layers of the organoclay, the interactions between PLA and PEG chains were enhanced and both components showed similar thermal characteristics, indicating lack of phase separation. These interactions further inhibited the interactions between the PLA chains and organic modifier of the organoclay

Narrow Spectrum Kilowatt-Level MOPA Seeded By Yb-Doped Random Fiber Laser

We proposed and experimentally demonstrated an approach to achieving a narrow spectrum kilowatt-level fiber master oscillator power amplifier (MOPA). The MOPA is seeded by a narrow spectrum random laser with Yb-doped fiber gain and has the spectral broadening-free feature. The narrow spectrum property is sustained during power scaling due to the suppression of nonlinear process. The frequency and time domain of the random laser are well characterized. The proposed one-stage scheme eventually produces 1.105- and 1.073-kW output at 1064 and 1067 nm, and the 3-dB bandwidth are 0.40 and 0.47 nm, corresponding to 0.38- and 0.37-nm random laser seed, respectively. The beam quality of $\text {M}^{2}\approx 1.4$ is achieved at 1.105-kW power level, and the proposed MOPA has the potential of wavelength tunability by simply tuning the fiber Bragg grating of random laser seed.

Switchable dual-wavelength SLM narrow linewidth fiber laser based on nonlinear amplifying loop mirror

Abstract We demonstrate a stable switchable dual-wavelength single longitudinal mode (SLM) narrow linewidth ytterbium-doped fiber (YDF) laser using a nonlinear amplifying fiber loop mirror (NALM) at 1064 nm. The NALM of intensity-dependent transmission acts as a saturable absorber filter and an amplitude equalizer to suppress mode competition and the fiber Bragg grating (FBG) pair is used as one wavelength selection component. By properly adjusting the polarization controllers (PCs), the switchable dual-wavelength SLM fiber laser can be operated steadily at room temperature. The optical signal-to-noise ratio (OSNR) is better than 50 dB for both lasing wavelengths. Meanwhile, the linewidth of the fiber laser for each wavelength is approximate 17.07 kHz and 18.64 kHz with a 20 dB linewidth, which means the laser linewidth is approximate 853 Hz and 932 Hz FWHM. Correspondingly, the measured relative intensity noise (RIN) is less than −120 dB/Hz at frequencies over 5.0 MHz.

Tunable narrow linewidth all-fiber thulium-doped fiber laser in a 2 µm-band using two Hi-Bi fiber optical loop mirrors

We propose an all-fiber Tm-doped fiber laser with a tunable and narrow laser line generated in a wavelength region of 2 µm. A single laser line with a linewidth below 0.05 nm, tunable in a wavelength range of 44.25 nm, is obtained. The laser linewidth and the discrete wavelength tuning range depend on the characteristics of the two fiber optical loop mirrors with high birefringence in the loop that forms the cavity. Dual-wavelength laser operation is also observed at tuning range limits with a wavelength separation of 47 nm. Alternate wavelength switching is also observed.

Linearly polarized narrow linewidth ytterbium-doped fiber laser at 1120 nm

Based on a spectrally symmetric cavity with respect to fiber Bragg grating bandwidth, using cladding pump technology, a 1120 nm continuous-wave narrow linewidth ytterbium-doped fiber laser is demonstrated. A maximum output power of 14.67 W is obtained corresponding to an optical efficiency of 63.5% to launched pump power. The measured center wavelength of the output laser is 1118.7 nm with a linewidth as narrow as 0.08 nm. The gain of the laser is more than 60 dB above the amplified spontaneous emission, and the polarization extinction ratio is 19.8 dB. As far as we are aware, this is the highest optical efficiency, largest amplified spontaneous emission suppression, and narrowest linewedth reported from cladding pumped linearly polarized 1120 nm fiber lasers.

Abstract 1883: Fibrillar 1D tumor microenvironment is the key driver associating high-speed tumor cell motility with nuclear shape in breast cancer

Abstract Unlike normal breast stroma, which contains curly collagen fibrils, aligned collagen fibers oriented perpendicular to blood vessels are seen in both human breast tumors and mouse models of breast cancer. These linear collagen fibers provide “highways” for tumor cells to migrate toward blood vessels in a directional migration mode known as tumor cell streaming. Streaming is characterized by tumor cell migration at high speed and directional persistence on 1D collagen fibers. Previous studies utilizing linear ECM substrates have shown that tumor cells adopt elongated morphology and display increased speeds on linear 1D substrates compared to their 2D motility. However, the relationship between 1D geometry of ECM fibers in breast tumor microenvironment and the underlying mechanotransduction mechanism regulating high-speed migration of tumor cells is not well understood. Here, we analyzed in vivo ECM architecture by SHG intravital imaging and found a narrow peak of fiber diameters falling in the range 2-3 µm. These fibers were composed of collagen I and fibronectin. Based on these findings, we developed a high fidelity in vitro nanofiber system to study the molecular mechanisms underlying tumor cell streaming migration. Breast carcinoma cells plated on 2 µm ECM-coated fibers showed enhanced motility matching in vivo velocities averaging 1.2 µm/min. We varied 1D fiber diameter (0.7-20 µm) and found that tumor cells move the fastest with highest persistence on smaller fibers within a narrow range of diameters from 0.7-3 µm. High tumor cell speeds correlated with enhanced alignments of F-actin and focal adhesions along the fiber axial dimension. Unexpectedly, we also observed nuclear deformation during carcinoma cell migration on narrow fibers in vitro, similar to nuclear deformation observed in vivo. This was a surprising finding because nuclear deformation in vivo was assumed to be caused by squeezing through ECM pores. Thus, we hypothesized that actomyosin forces not only regulate cell motility parameters, but also nuclear deformation independently of ECM pore size. To test this hypothesis, we disrupted the transmission of cytoskeletal forces to the nucleus by knocking down LINC complex proteins - SUN1 and SUN2, and found increased nuclear elongation and cell motility parameters, through the upregulation of actin polymerization. These results indicate that in carcinoma cells, F-actin associated forces are shared between the leading edge (to maintain cell speed) and the nucleus (to dynamically regulate nuclear shape). LINC complex disruption releases F-actin forces acting on the nucleus to the cell front, leading to higher tumor cell motility speeds. In summary, our results provide new insights into the interplay between actomyosin contractility and the LINC complex in the regulation of nuclear shape and high-speed tumor cell motility during carcinoma cell metastasis. Citation Format: Ved P. Sharma, James Williams, Edison Leung, Joseph Sanders, Robert Eddy, James Castracane, John Condeelis. Fibrillar 1D tumor microenvironment is the key driver associating high-speed tumor cell motility with nuclear shape in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1883. doi:10.1158/1538-7445.AM2017-1883

Compact Narrow Linewidth Actively Q-Switched Er–Yb Double-Clad Fiber Laser

Actively Q-switched laser operation of a narrow linewidth compact fiber laser based on an Er–Yb double-clad fiber is presented. The laser linewidth as a function of the repetition rate and the Q-switched pulses characteristics for different pump powers are experimentally analyzed. Stable Q-switched laser operation with spectral laser linewidth of 73 pm in a repetition rate range from 90 to 270 kHz is obtained. The minimum pulse duration of 178 ns, maximum peak power of 30.5 W, and maximum pulse energy of 5.4 µJ are observed. The maximum average power reached is 1.1 W.

Environmentally Stable Pulse Energy-Tunable Picosecond Fiber Laser

We have reported a mode-locked pulse energy tunable ytterbium-doped fiber laser constructed by the polarization-maintaining (PM) fibers with a position-tunable focuser and a semiconductor-saturable absorber mirror (SESAM). The narrow bandwidth fiber Bragg grating in the cavity produces self-starting picosecond (ps) mode-locked operation. The linear laser cavity achieved tunable single pulse energy varied from 0.591 to 0.988 nJ, with a 24.7-MHz repetition rate and a 6.03-ps pulse duration at 1064.18 nm. High environmental stability is also confirmed by a high polarization extinction ratio over 17.8 dB.

基于π相移光纤布拉格光栅的窄线宽掺铒光纤激光器

基于π相移光纤布拉格光栅的窄线宽掺铒光纤激光器