The growing use of carbon and glass fibres has increased awareness about their waste disposal methods. Tonnes of composite waste containing valuable carbon fibres and glass fibres have been ...cumulating every year from various applications. These composite wastes must be cost-effectively recycled without causing negative environmental impact. This review article presents an overview of the existing methods to recycle the cumulating composite wastes containing carbon fibre and glass fibre, with emphasis on fibre recovery and understanding their retained properties. Carbon and glass fibres are assessed via focused topics, each related to a specific treatment method: mechanical recycling; thermal recycling, including fluidised bed and pyrolysis; chemical recycling and solvolysis using critical conditions. Additionally, a brief analysis of their environmental and economic aspects are discussed, prioritising the methods based on sustainable values. Finally, research gaps are identified to highlight the factors of circular economy and its significant role in closing the life-cycle loop of these valuable fibres into re-manufactured composites.
Optical fiber modes carrying orbital angular momentum (OAM) have many applications, for example in mode-division-multiplexing for optical communications. The natural guided modes of N -fold ...rotationally symmetric optical fibers, such as most photonic crystal fibers, are helical Bloch modes (HBMs). HBMs consist of a superposition of azimuthal harmonics (order m ) of order <inline-formula><tex-math notation="LaTeX">\ell _{\rm{A}}^{(m)} = \ell _{\rm{A}}^{(0)} + mN</tex-math></inline-formula>. When such fibers are twisted, these modes become circularly and azimuthally birefringent, that is to say HBMs with equal and opposite values of <inline-formula><tex-math notation="LaTeX">\ell _{\rm{A}}^{(0)}</tex-math></inline-formula> and spin s are non-degenerate. In this article we report the use of Bragg mirrors to reflect and convert HBMs in a twisted three-core photonic crystal fiber, and show that by writing a tilted fiber Bragg grating (FBG), reflection between HBMs of different orders becomes possible, with high wavelength-selectivity. We measure the near-field phase and amplitude distribution of the reflected HBMs interferometrically, and demonstrate good agreement with theory. This new type of FBG has potential applications in fiber lasers, sensing, quantum optics, and in any situation where creation, conversion, and reflection of OAM-carrying modes is required.
The history, fabrication, theory, numerical modeling, optical properties, guidance mechanisms, and applications of photonic-crystal fibers are reviewed
In this letter, a nonlinear semi-analytical model (NSAM) for simulation of few-mode fiber transmission is proposed. The NSAM considers the mode mixing arising from the Kerr effect and waveguide ...imperfections. An analytical explanation of the model is presented, as well as simulation results for the transmission over a two mode fiber (TMF) of 112 Gb/s using coherently detected polarization multiplexed quadrature phase-shift-keying modulation. The simulations show that by transmitting over only one of the two modes on TMFs, long-haul transmission can be realized without increase of receiver complexity. For a 6000-km transmission link, a small modal dispersion penalty is observed in the linear domain, while a significant increase of the nonlinear threshold is observed due to the large core of TMF.
We present a novel switchable multi-wavelength Er-doped mode-locked fiber laser built on graded-index multimode fiber (GIMF)-photonic crystal fiber (PCF)-GIMF-based saturable absorber in this paper. ...The mode-locked pulses achieve a fundamental repetition rate of 18.72 MHz and signal-to-noise ratio of 48 dB. The GIMF-PCF-GIMF also acts as a Mach Zehnder interferometer to obtain single-, dual-, triple- and quadruple-wavelength switching mode-locked lasing output by changing the polarization state. The single-wavelength and dual-wavelength lasers generated by this device have the characteristic of wavelength tunability, and the wavelength tuning ranges are 25.29 nm and 7.26 nm, respectively. The new switchable multi-wavelength mode-locked fiber laser can simultaneously provide light sources for multiple channels in high-speed and large-capacity fiber communication systems, making the design of optical transmitters more compact and economical.
We investigate the microhole collapse property of different photonic crystal fibers (PCFs) and its effect on the splice loss using an electric arc fusion splicer. The physical mechanism of the splice ...loss for different kinds of PCFs is studied, and a guideline for splicing these PCFs and conventional single-mode fibers (SMFs) is proposed. We demonstrate a low-loss fusion splicing of five different PCFs with SMFs, including large-mode PCF, hollow-core PCF, nonlinear PCFs, and polarization-maintaining PCF.
This research demonstrates how low loss commercially available multi-mode (MM), perfluorinated polymer optical fibers (POFs) can be used for robust and reliable fiber Bragg grating (FBG) based ...sensing. A single peak FBG reflection spectrum is achieved by tapering the fiber to a diameter just small enough to make the fiber effectively single-moded and then inscribing the FBG in the waist section of the taper. Here we use plane-by-plane, direct writing inscription with a femtosecond laser. In particular we used the GigaPOF-50SR MM fiber and tapered it by a factor of 0.24, which was found to be the critical ratio that provided a single grating reflection peak. The GigaPOF-50SR fiber was chosen because it allows operation at 1550 nm and has a suitable small 50 μm core diameter, which minimizes the required taper ratio and thus the insertion loss of the taper. The FBG sensor was found to have a strain and relative humidity sensitivity of 20 nm/%strain and ∼ 6.7 pm/%RH, respectively. The grating proved to be largely insensitive to temperature. This approach to single-mode POF sensor fabrication will enable multi-point strain sensing at 1550 nm over 50 m long fiber. It combines the main advantages of single mode POFs (robust FBG sensing) and MM POFs (low transmission loss) and demonstrates that tapered MM POFs constitute an efficient solution for the development of robust and reliable long distance POF FBG sensor networks.
•Impact behaviour of Hybrid Fibrous Geopolymer Composite (HFGC) is tested and investigated.•Influences of impact strength and fibre content on HFGC are addressed.•Scattered experimental impact test ...results of HFGC is analysed using Weibull distribution.•Impact energy of HFGC is analysed and modelled.
The latest research data indicates that geopolymer concrete reinforced with mono fibre has a remarkable enhancement in its impact strength and fracture toughness, which is well documented. Nevertheless, many aspects of impact behaviour of Hybrid Fibrous Geopolymer Composites (HFGC) are still unexplored, which are of primary importance for defense projects in the world. For the first time, the impact behaviour under falling weight collision of HFGC were evaluated and further analysed. The HFGC mixtures were fabricated using three different fibres viz., 5D hooked end steel, polypropylene and glass. The main parameters studied were the fibre dosage and amalgamations of different fibres. Totally seven mixes were prepared and further investigations were conducted in two phases. In the first phase, five cylindrical specimens were fabricated for each mix and tested as per the ACI committee 544 falling weight collision test recommendations. Subsequently, a comprehensive two-parameter Weibull distribution was executed to scrutinise the scattered experimental test results of cylindrical specimens and presented in terms of reliability function. In the second phase, prism specimens were fabricated and tested under the same falling weight collision. Then, an analytical model was formulated for evaluating the impact energy at failure of HFGC prism specimens and comparisons were made with experimental data. The hybridisation of the above three fibres at a certain dosage and incorporation in geopolymer composites led to an enhanced impact performance and ductility properties. Further, the obtained impact energy at failure from modelling well agrees with the experimental results. Henceforth, it is a successful research data that is presented herein which will be eminently valuable for understanding the performance of new fibrous geopolymer composites (FGC) made with hybrid fibres that which are available all over the world.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The integration of conventional silica optical fibers with optoelectronic materials and electrical structures opens the door to miniaturized and multifunctional all-fiber optoelectronic systems with ...actively controllable capabilities. The flat endface of an optical fiber tip offers a naturally light-coupling microscopic platform for optoelectronic integration using optimized micro- and nano-fabrication techniques. In recent decades, the increasing demand for active fiber devices has created opportunities to develop various optoelectronic structures on fiber tips, from integrating high-performance single modules for specific applications to integrating multi-function multiple modules for more complex applications. In this paper, we review the rapid development of fiber-compatible fabrication technologies for building optoelectrical circuits on fiber endfaces. Then, we discuss the fast-progressing field of active fiber tips along with its wide applications, including photodetection, modulation, lasing, sensing, and light-emitting. Finally, we discuss challenges and opportunities for future development in this field. We believe that this scheme of active fiber tips will pave the way for next-generation ultracompact optical fiber systems with diverse optical and optoelectronic applications.
In this paper, a novel dual-wavelength wide-spectrum erbium-doped fiber ring laser (EDFRL) for optical fiber sensing system is proposed and experimentally demonstrated. The output of EDFRL is ...theoretically simulated and classified depending on the theoretical analysis of laser threshold condition into "excited state" and "nonexcited state". The influence of pump wavelength, fiber laser configuration, EDF length and output coupling ratio of EDFRL is discussed. The EDFRL pumped at 1480 nm wavelength and backward-pumped mode could achieve the stable maximum wide-spectrum output power. The output power fluctuation is lower than 0.06 dB and the center wavelengths shift is less than 0.01 nm. The practicability of EDFRL in a hybrid M-Z and Sagnac interferometer optical fiber sensing system is demonstrated through the comparison of SLD and EDFRL. Consequently, the EDFRL proposed in this study is expected to replace the traditional SLD in the optical fiber interferometric sensing system at a lower cost.
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