Fiber Devices Research Articles

Microstructured multimaterial fibers for efficient optical detection

AbstractFlexible optoelectronic fibers are recognized as one type of important building block for the system of wearable electronics and advanced functional textiles. The thermal drawing process offers promise for scalable construction of optoelectronic fibers, while they are generally characterized by the continuous cylindrical structure and poor electrical property. Here, we report the fabrication and characterization of the flexible structured multimaterial fibers thermally drawn from the combination of metal‐semiconductor‐polymer, and control of their inner structure via fluid Plateau‐Rayleigh instability. A trapezoidal electrical connection configuration with the semiconductor spheres clamped by two metal electrodes inside the fiber is successfully achieved based on this fluid instability. The obtained structured multimaterial fiber shows better photoresponse properties than that of the as drawn multimaterial fiber. The findings open new opportunity to develop fiber devices for efficient optical detection.

Polarization control for fiber systems and devices

Nulling the birefringence effect of a light signal traveling through a single-mode fiber when the fiber behaves as an elliptical retarder can be achieved by winding the fiber as a double-helix. We present a resume of the theory and procedures developed at CICESE to demonstrate this polarization control in fiber systems.

Transverse Asymmetry of the Index Modulation Profile in Few-Mode Fiber Bragg Grating

The transverse asymmetry of the index modulation profile in the asymmetric few-mode fiber Bragg grating (FM-FBG) was investigated. The transverse asymmetry of the index modulation profile will lead to mode conversion between modes with the different azimuthal orders, and this asymmetry is characterized by the attenuation coefficient α. We evaluated that the value of attenuation coefficient α was 0.2 μm−1, and grating amplitude χ was 2.8 × 10−4 for FM-FBG inscribed by UV single-side illumination. We found that the optimized value of α was 0.16 μm−1, at which the maximum mode conversion efficiency of LP01–LP11 can be achieved. The results of this paper provide great potential application in few-mode fiber (FMF) devices and mode division multiplexing (MDM) optical communication.

Tunable and dual-wavelength mode-locked Yb-doped fiber laser based on graded-index multimode fiber device

We have implemented wavelength-tunable and dual-wavelength in an ytterbium-doped passively mode-locked fiber laser using a single mode-graded index multimode-single mode fiber (SMF-GIMF-SMF) device as the saturable absorber (SA) without additional components. Such an all-fiber SA device exhibits fantastic properties with a large modulation depth of 22.9%, a small saturation fluence of 8.3 μJ/cm2, and the transmission curve with a capacity of gain-flattening, which are suitable for the tunable mode-locking generation. Benefiting from the intracavity birefringence-induced filtering effect of the laser cavity, tuning and dual-wavelength operations are obtained. For the tuning operation, the central wavelength of the dissipative solitons (DSs) can be tuned from 1028.5 to 1074.4 nm, with the pulse duration of tens of picoseconds. For the dual-wavelength mode-locking operation, the central wavelengths of dual-wavelength can be switched from 1032.3/1054.1 nm to 1049.3/1072.6 nm. Our results indicate that the SMF-GIMF-SMF device provides a novel platform for wavelength-tunable and dual-wavelength mode-locking in Yb-doped fiber lasers.

Recent advances in functional fiber electronics

AbstractRapid development of wearable electronics with various functionalities has stimulated the demand to construct functional fiber devices due to their merits of mechanical flexibility, weavability, miniaturization, and integrability. To this end, fiber components which can realize the functions of energy storage and conversion, actuating plus sensing have gained increasing concerns. Herein, we summarize the recent progress with respect to fiber material preparation, innovative structure design, and device performance in this review, also highlighting the possibility of integrated fiber electronics as an extension of application, the remaining challenges and future perspectives toward next‐generation smart systems and to facilitate their commercialization.

Rapid and label free detection of aflatoxin B1 in alcoholic beverages with a microfluid fiber device.

A rapid and label free aflatoxin B1 (AFB1) microfluid sensor was proposed and tested. The device was fabricated with hollow-core photonics crystal fiber infiltrated with the AFB1 solution. The autofluorescence emitting from the AFB1 molecules was detected. The sensor length was optimized. The AFB1 concentration was tested with a 4 cm long sensor. The best limit of detection was achieved as low as 1.34 ng/ml, which meets the test requirement of the national standards for AFB1 in food. The effectiveness of this sensor being applied in beer solution was also verified to be a little more sensitive than in aqueous solution. Compared with traditional AFB1 detection methods, the proposed single-ended device perfectly satisfies the demand of process control in alcoholic beverages manufacture.

High-performance coaxial piezoelectric energy generator (C-PEG) yarn of Cu/PVDF-TrFE/PDMS/Nylon/Ag

Coaxial type piezoelectric energy generator (C-PEG) nanofiber was fabricated by a self-designed continuous electrospinning deposition system. Piezoelectric PVDF-TrFE nanofiber as an electroactive material was electrospun at a discharge voltage of 9–12 kV onto a simultaneously rotating and transverse moving Cu metal wire at an angular velocity of ω g = 60–120 RPM. The piezoelectric coefficient d33 of the PVDF-TrFE nanofiber was approximately −20 pm V−1. The generated output voltage (V G) increased according to the relationship exp(-α P) (α = 0.41– 0.57) as the pressure (P) increased from 30 to 500 kpa. The V G values for ten and twenty pieces of C-PEG were V G = 3.9 V and 9.5 V at P = 100 kpa, respectively, relatively high output voltages compared to previously reported values. The high V G for the C-PEG stems from the fact that it can generate a fairly high V G due to the increased number of voltage collection points compared to a conventional two-dimensional (2-dim) capacitor type of piezoelectric film or fiber device. C-PEG yarn was also fabricated via the dip-coating of a PDMS polymer solution, followed by winding with Ag-coated nylon fiber as an outer electrode. The current and power density of ten pieces of C-PEG yarn were correspondingly 22 nA cm−2 and 8.6 μW cm−3 at V G = 1.97 V, higher than previously reported values of 5.54 and 6 μW cm−3. The C-PEG yarn, which can generate high voltage compared to the conventional film/nanofiber mat type, is expected to be very useful as a wearable energy generator system.

Coating of Conducting and Insulating Threads with Porous MOF Particles through Langmuir-Blodgett Technique.

The Langmuir-Blodgett (LB) method is a well-known deposition technique for the fabrication of ordered monolayer and multilayer thin films of nanomaterials onto different substrates that plays a critical role in the development of functional devices for various applications. This paper describes detailed studies about the best coating configuration for nanoparticles of a porous metal-organic framework (MOF) onto both insulating or conductive threads and nylon fiber. We design and fabricate customized polymethylmethacrylate sheets (PMMA) holders to deposit MOF layers onto the threads or fiber using the LB technique. Two different orientations, namely, horizontal and vertical, are used to deposit MIL-96(Al) monolayer films onto five different types of threads and nylon fiber. These studies show that LB film formation strongly depends on deposition orientation and the type of threads or fiber. Among all the samples tested, cotton thread and nylon fiber with vertical deposition show more homogenous monolayer coverage. In the case of conductive threads, the MOF particles tend to aggregate between the conductive thread’s fibers instead of forming a continuous monolayer coating. Our results show a significant contribution in terms of MOF monolayer deposition onto single fiber and threads that will contribute to the fabrication of single fiber or thread-based devices in the future.

Vitrification of mouse two-cell and blastocyst stage embryos in simplified closed system using either a hemi-straw or a hollow fiber device.

Two-cell stage and blastocyst stage mouse embryos were equilibrated in a medium containing 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 8-15 min. Vitrification was performed in a medium containing 0.5M sucrose and either 15% EG + 15% DMSO, 17.5% EG + 17.5% DMSO, or 20% EG + 20% DMSO for 30 s. They were then placed either on a hemi-straw (HS) or a hollow fiber vitrification (HFV) device and vitrified by cooled air inside a 0.5-ml straw. In two-cell embryos, a 100% survival rate was obtained from all groups except the 20% HS group (P > .05). All vitrified two-cell groups showed similar rates of blastocyst development to that of fresh control group (P > .05), except 17.5% and 20% HFV groups, which were significantly lower than the other groups (P < .05). In the blastocyst embryos, the HFV groups were divided into two subgroups (non-collapsed; HFV-NC and collapsed; HFV-C blastocyst). Re-expansion rate in 15% HFV-NC, 17.5% HFV-NC, and 15% HFV-C groups was reduced (P < .05), whereas the rest were similar to control. In conclusion, we established a simplified, reliable, and closed system for HFV vitrification applying hemi-straw, which does not require skilled practitioners.

Review of microfluidic approaches for fabricating intelligent fiber devices: importance of shape characteristics.

Shape characteristics, which include the physical dimensions (scale), apparent morphology, surface features, and structure, are essential factors of fibrous materials and determine many of their properties. Microfluidic technologies have recently been proposed as an approach for producing one-dimensional (1D) fibers with controllable shape characteristics and particle alignment, which impart specific functionality to the fiber. Moreover, superfine 1D fibers with a high surface area and ordered structure have many potential applications as they can be directly braided or woven into textiles, clothes, and tissues with two- or three-dimensional (2D or 3D) structures. Previous reviews of microfluidic spinning have not focus on the importance of the shape characteristic on fiber performance and their use in intelligent fiber design. Here, the latest achievements in microfluidic approaches for fiber-device fabrication are reviewed considering the underlying preparation principles, shape characteristics, and functionalization of the fibers. Additionally, intelligent fiber devices with shapes tailored by microfluidic approaches are discussed, including 1D sensors and actuators, luminous fibers, and devices for encoding, energy harvesting, water collection, and tissue engineering applications. Finally, recent progress, challenges, and future perspectives of the microfluidic approaches for fiber device fabrication are discussed.

Electrically tunable optical fiber device based on hollow-core fiber infiltrated with liquid crystal

An electrically tunable optical fiber device based on Mach-Zehnder interferometer and electro-optic effect of the liquid crystal is proposed. The Mach-Zehnder interferometer is constructed by splicing a section of hollow-core fiber infiltrated with the E7 liquid crystal between an input single-mode fiber and an output single-mode fiber. The resonance wavelength of the spectrum transmitted from the proposed sensing probe is modulated by the applied alternating current electric field. Experimental results show that the maximum sensitivity of this device is 1.2248 nm/V in the range of 130 V–152 V, and the limit of detection is 0.01633 V. Besides, the proposed device shows the advantages of excellent repeatability, low cost, easy fabrication, compact size, and high sensitivity, which has potential applications in wavelength-tunable electro-optical devices, photoelectric switches, and electric field sensors.

Development of Gun-type Tube-Guide Device of Laser Fiber

With the development of laryngeal microsurgery, the requirements for the flexibility and convenience of surgical instruments are increasing. The research on related instruments has important value for the clinical application of laryngeal microsurgery. We have redesigned a gun-type tube-guide device of laser fiber by comparing the shortcomings of existing laser fiber introducers. The innovation of this design lies in its rotating nut device with adjustable laser angle and pre-bent tip. The corresponding in vitro laryngeal model experiment can realize multi-angle rotation of the instrument in the laryngeal cavity, which greatly increases the scope of laser surgery. During the operation, the rotating nut can be directly adjusted to avoid repeatedly removing the instrument to adjust the angle, which greatly improves the practicability and simplicity of the operation, which is worthy of further clinical research and promotion.

Micro/nanofiber-based noninvasive devices for health monitoring diagnosis and rehabilitation

Recently, in healthcare sectors, specifically for personalized health monitoring, motion sensing, and human–machine interactions, the rising demand for stretchable and soft electronic devices is significant. In particular, stretchable, skin mountable, breathable, wearable, light weight, and highly sensitive sensors are needed for detecting subtle deformation arising from human physiological signals and have potential applications in health diagnosis. In this review, we discuss flexible, noninvasive, and wearable sensors based on micro/nanofibers with unique sensing capabilities for detecting human vital signs such as body motion, temperature, heartbeat, respiration rate, and blood glucose level, which have applications in both fitness-monitoring and medical diagnosis. Here, the latest successful examples of micro/nanofiber based flexible and wearable human vital signs monitoring sensors in the form of film, mat, yarn, fabric, textiles, etc., are outlined and discussed in detail. Discussion includes the fiber fabrication technique, sensing mechanism, device structure, sensor performance, and data processing. Some of the latest fabricated self-powered devices with integrated sensing platforms are also reviewed. Finally, this article reveals the existing challenges that are still to be overcome associated with wearable technologies for applications in health monitoring, diagnosis, and rehabilitation.

Controllable polarization electro-optic absorption graphene modulator

Graphene, as two-dimensional material with many properties of the gate-voltage tunable Fermi-level and zero band gap, can be utilized for optical modulators by the integration with other material. In this work, an electro-optic modulator based on the fiber-surface waveguide and graphene capacitance has been proposed with the device length of 50 μm, featuring excellent controllable polarization modulation (polarization extinction ratio over 0.12 dB/μm), large modulation bandwidth of ∼40 GHz @ hBN and ∼25 GHz @ Al2O3, and energy consumption low to 11.5 pJ/bit for hBN and 4 pJ/bit for Al2O3. The polarization can be controlled by tuning the core radius from 130 nm for the TE polarized modulation with modulation efficiency over ∼2.56 dB V−1 (Al2O3) and ∼1.15 dB V−1 (hBN) to 170 nm for the TM polarized modulation efficiency up to ∼3.03 dB V−1 (Al2O3) and ∼1.3 dB/V (hBN). This work not only promotes the development of future polarization modulation technology, but also paves the way toward multifunctional fiber devices and systems.

Photobiomodulation by a new optical fiber device: analysis of the in vitro impact on proliferation/migration of keratinocytes and squamous cell carcinomas cells stressed by X-rays.

Photobiomodulation-based (PBM-based) therapies show promising results in mucositis and dermatitis treatment by stimulating wound healing mechanisms such as cell proliferation and migration. The aim of the present study is to investigate the in vitro effects of CareMin650 on the proliferation and migration of two different types of cells, namely cancer and non-cancer cells, with or without X-ray radiation. Study design used PBM through a combination of 0-3-6 J/cm2 doses-with or without X-ray radiation-on the proliferation and migration capabilities of a keratinocyte cell line (HaCaT) and a squamous cell carcinoma line (SCC61). PBM is delivered by a new woven optical fiber device, namely CareMin650 prototype (light emission by LEDs (light-emitting diodes), peak at 660 nm, irradiance of 21.6 mW/cm2). The effectiveness of PBM to increase HaCaT proliferation and migration (with or without X-ray radiation) supports the capability of PBM to favor wound healing. It also highlights that PBM does not provide any anti-radiation effect to previously X-rays radiated SCC (p < 0.001). Such data supports the beneficial effect of PBM delivered by an optical fiber device to heal wounds, without promoting cancer development.

Broadband silicon core photonics crystal fiber polarization filter based on surface plasmon resonance effect

In this article, a panda-like silicon core based photonics crystal fiber was proposed and applied onto a polarization filter. Au film coating surrounding the air holes acted as a plasmonic active metal. Using the Finite element method, the quality of the proposed fiber was investigated, including confinement loss and extinction ratio. By adjusting the length of the proposed fiber, the applicable operating wavelength region could reach up to 1μm easily. Thus when the length increased to 6 mm, the wavelength band covered fiber communication band was also obtained. As a result, the proposed silicon core photonics crystal fiber achieved a good filtering effect in the near-infrared, even extending to mid-infrared. Moreover, the proposed fiber device can easily integrate with the existing optical fiber communication and sensing system.

Design and experimental study of a new type of 45° overflow falling film distributor

A petrochemical acrylic fiber factory introduced a set of acrylic fiber device in the 1980s. Among them, the evaporation device used for solvent recovery of acrylic fiber appeared to be difficult to heat exchange in the tube. In order to solve the problem, we designed a new 45° overflow falling film distributor device and an experimental system for single tube. The effects of flow rate, liquid level and orifice flow coefficient were investigated experimentally. The results show that the correlation between the orifice flow coefficient and the structure size of the fabric determines the film formation effect. When the flow rate of the single tube is constant, the absolute error of the orifice flow coefficient does not exceed 9%. Therefore, the orifice flow coefficient proposed in this experiment is a good guide to the optimal design of the fabric size.

Notice of Removal: Practical Simulation Method on Multimode-No-Core-Multimode Fiber Structure Based on the Mode Expansion

In this paper, a simplified simulation method for multimode-no-core-multimode (MNM) fiber structures is developed and demonstrated. The method is based on the mode expansion in the vectorial form, taking account of a complete set of guided modes. The simulated results are in good agreement with the experimental results. Also, it is shown that mode distribution of an input multimode fiber (MMF) is an influence on multimode interference(MMI) in the MNM fiber structure and can be controlled by using a single mode fiber(SMF) segment coupled to it. The proposed method provides an effective way for the designs of multimode-interference(MMI)-based fiber devices, which particularly contain a lot of modes.

Optical Fiber Integrated Functional Micro-/Nanostructure Induced by Two-Photon Polymerization

Owing to the limitation of optical fiber materials and conventional fabrication methods, the development of optical fiber devices has encountered a bottleneck. Recently, two-photon polymerization technology are attracting increasing research interest due to its superiorities of high precision, flexibility and diversity of polymer materials. The optical fiber integrated micro-/nanostructures realized by two-photon polymerization have become a research hotspot due to the great application expansion of optical fiber device. In this paper, we review the research progress in the field of optical fiber integrated micro-/nanostructure induced by two-photon polymerization in the last ten years, which are classified by micro-optics, optical waveguide device and optical micro-cavity. Furthermore, we briefly discussed the future prospects of this exciting research field.

A Hierarchical Structured Ultrafine Fiber Device for Preventing Postoperative Recurrence and Metastasis of Breast Cancer

AbstractThe high incidence of postoperative recurrence and metastasis has a serious effect on survival in breast cancer patients. Moreover, it is still a great challenge to prevent the postoperative recurrence and metastasis through traditional implantable devices due to their inability to control multiple drug release. Herein, an implantable hierarchical structured ultrafine fiber device with a time‐programmed drug release function for the local postoperative adjuvant chemotherapy of breast cancer is developed. The structure is obtained through a co‐axial electrospinning technology by the formation of the periodically arranged chambers inside a fiber matrix. The Doxorubicin hydrochloride in these chambers is released rapidly, killing the residual tumor cells to prevent tumor recurrence; while the matrix metalloproteinases‐2 (MMP‐2) inhibitor disulfiram in the fiber matrix is released in a sustained manner, inhibiting tumor invasion to prevent its metastasis. The fiber device implanted in tumor‐bearing mice after a surgical tumor reduction displays excellent therapeutic efficacy by preventing both recurrence and metastasis. The mechanism investigation of tumor invasion through the type‐II collagen immunofluorescence analysis reveals that the decrease of the activity of MMP‐2 plays a key role in this process.