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11 pages, 2246 KiB

Open AccessArticle

Surface-Enhanced Raman Scattering in Silver-Coated Suspended-Core Fiber

by Yangyang Xu, Xian Zhang, Xiao-Song Zhu and Yi-Wei Shi

Sensors 2024, 24(1), 160; https://doi.org/10.3390/s24010160 - 27 Dec 2023

Viewed by 2006

In this paper, the silver-coated large-core suspended-core fiber (LSCF) probe was fabricated by the dynamic chemical liquid phase deposition method for surface-enhanced Raman scattering (SERS) sensing. The 4-mercaptophenylboronic acid (4-MPBA) monolayer was assembled in the LSCF as the recognition monolayer. Taking advantage of [...] Read more.

In this paper, the silver-coated large-core suspended-core fiber (LSCF) probe was fabricated by the dynamic chemical liquid phase deposition method for surface-enhanced Raman scattering (SERS) sensing. The 4-mercaptophenylboronic acid (4-MPBA) monolayer was assembled in the LSCF as the recognition monolayer. Taking advantage of the appropriate core size of the LSCF, a custom-made Y-type optical fiber patch cable was utilized to connect the semiconductor laser, Raman spectrometer, and the proposed fiber SERS probe. The SERS signal is propagated in the silver-coated air channels, which can effectively reduce the Raman and fluorescence background of the silica core. Experiments were performed to measure the Raman scattering spectra of the 4-MPBA in the silver-coated LSCF in a non-enhanced and enhanced case. The experiment results showed that the Raman signal strength was enhanced more than 6 times by the surface plasmon resonance compared with the non-enhanced case. The proposed LSCF for SERS sensing technology provides huge research value for the fiber SERS probes in biomedicine and environmental science. The combination of SERS and microstructured optical fibers offers a potential approach for SERS detection Full article

(This article belongs to the Section Optical Sensors)

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15 pages, 24941 KiB

Open AccessArticle

Torsional Optical Fiber Stress Analysis and Vortex-Induced Vibration Study of Three-Core Submarine Cable

by Haotian Tan, Yanpeng Hao, Peng Zhang, Qishun Li, Wanxing Tian, Linhao Chen, Lin Yang and Licheng Li

J. Mar. Sci. Eng. 2023, 11(8), 1589; https://doi.org/10.3390/jmse11081589 - 14 Aug 2023

Cited by 3 | Viewed by 1950

Abstract

Due to current scouring, submarine cables are prone to be exposed, suspended, and even vortex-induced vibration, which is not conducive to the safe operation of the power grid. In this contribution, the finite element simulation model of a 35 kV three-core optical fiber [...] Read more.

Due to current scouring, submarine cables are prone to be exposed, suspended, and even vortex-induced vibration, which is not conducive to the safe operation of the power grid. In this contribution, the finite element simulation model of a 35 kV three-core optical fiber composite submarine cable with a suspended span length of 9.5 m is established. The natural frequency of the model is obtained through modal analysis. Then the vortex-induced vibration is simulated by the fluid–structure coupling method, and the stress distribution and change law of the torsional optical fiber is extracted. The results show that in the submarine cable, there appears to be a beating vibration and locking phenomena respectively, under two flow velocities. The transverse vibration amplitude of the latter increases significantly due to a resonance state. When the flow direction is perpendicular to the submarine cable, the stress distribution of the torsional optical fiber at the initial moment and at the 1/2 T moment of a vibration cycle approximately represents a mirror image relationship. In addition, the frequency of the stress change is the same as the frequency of the vortex-induced vibration, which can judge whether the vortex-induced vibration occurs. Moreover, the vortex-induced vibration range can be determined by the maximum stress change location. Full article

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13 pages, 3878 KiB

Open AccessArticle

Monitoring the Vital Activity of Microalgae Cells Using a Fiber-Optical Refractometer

by Dmitriy P. Sudas, Petr I. Kuznetsov, Evgeny A. Savelyev and Konstantin M. Golant

Photonics 2023, 10(1), 19; https://doi.org/10.3390/photonics10010019 - 24 Dec 2022

Cited by 4 | Viewed by 2448

Abstract

Using the technology of metalorganic chemical vapor deposition (MOCVD), fully fiber refractometers based on the lossy mode resonance (LMR) were obtained and investigated. The sensors are made on the basis of a section of optical fiber etched to the core with films of [...] Read more.

Using the technology of metalorganic chemical vapor deposition (MOCVD), fully fiber refractometers based on the lossy mode resonance (LMR) were obtained and investigated. The sensors are made on the basis of a section of optical fiber etched to the core with films of titanium dioxide (TiO₂) and tin (TiO₂/SnO₂) deposited on the side surface. The sensitivity of the obtained sensors to the refractive index of the surrounding liquid medium is compared depending on the composition and thickness of the film coating. The sensitivity of the fiber sensor with a two-layer coating in the wavelength range of 1.33–1.35 microns was 4850 nm/RIU. Before measurements, cells suspended in liquid were concentrated on the surface of the sensor due to the effect of optical tweezer. Particles were attracted from the suspension when launching into the fiber radiation from a diode laser with a power of 10 mW. With the help of fabricated fiber sensors, the change in the refractive index of a suspension containing living cells of the microalgae Chlorella Vulgaris was monitored. The possibility of assessing the influence of external conditions on the life process of algae with real-time control using fabricated fiber sensors is shown. Full article

(This article belongs to the Section Lasers, Light Sources and Sensors)

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8 pages, 2021 KiB

Open AccessArticle

Nano-Optomechanical Resonators Based on Suspended Graphene for Thermal Stress Sensing

by Shen Liu, Hang Xiao, Yanping Chen, Peijing Chen, Wenqi Yan, Qiao Lin, Bonan Liu, Xizhen Xu, Yiping Wang, Xiaoyu Weng, Liwei Liu and Junle Qu

Sensors 2022, 22(23), 9068; https://doi.org/10.3390/s22239068 - 23 Nov 2022

Cited by 5 | Viewed by 2688

Abstract

Nanomechanical resonators made from suspended graphene combine the properties of ultracompactness and ultrahigh detection sensitivity, making them interesting devices for sensing applications. However, nanomechanical systems can be affected by membrane stress. The present work developed an optomechanical resonator for thermal stress sensing. The [...] Read more.

Nanomechanical resonators made from suspended graphene combine the properties of ultracompactness and ultrahigh detection sensitivity, making them interesting devices for sensing applications. However, nanomechanical systems can be affected by membrane stress. The present work developed an optomechanical resonator for thermal stress sensing. The proposed resonator consists of a section of hollow core fiber (HCF) and a trampoline graphene–Au membrane. An all-optical system that integrated optical excitation and optical detection was applied. Then, the resonance frequency of the resonator was obtained through this all-optical system. In addition, this system and the resonator were used to detect the membrane’s built-in stress, which depended on the ambient temperature, by monitoring the resonance frequency shift. The results verified that the temperature-induced thermal effect had a significant impact on membrane stress. Temperature sensitivities of 2.2646 kHz/°C and 2.3212 kHz/°C were obtained when the temperature rose and fell, respectively. As such, we believe that this device will be beneficial for the quality monitoring of graphene mechanical resonators. Full article

(This article belongs to the Special Issue Novel Optical Fiber Sensors)

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10 pages, 6169 KiB

Open AccessArticle

Optical Fiber Sensor for Curvature and Temperature Measurement Based on Anti-Resonant Effect Cascaded with Multimode Interference

by Yinqiu Gui, Qian Shu, Ping Lu, Jiajun Peng, Jiangshan Zhang and Deming Liu

Sensors 2022, 22(21), 8457; https://doi.org/10.3390/s22218457 - 3 Nov 2022

Cited by 8 | Viewed by 2344

Abstract

In this paper, a novel inline optical fiber sensor for curvature and temperature measurement simultaneously has been proposed and demonstrated, which can measure two parameters with very little crosstalk. Two combinational mechanisms of anti-resonant reflecting optical waveguide and inline Mach–Zehnder interference structure are [...] Read more.

In this paper, a novel inline optical fiber sensor for curvature and temperature measurement simultaneously has been proposed and demonstrated, which can measure two parameters with very little crosstalk. Two combinational mechanisms of anti-resonant reflecting optical waveguide and inline Mach–Zehnder interference structure are integrated into a 3 mm-long single hole twin suspended core fiber (SHTSCF). The 85 μm hole core gives periodic several dominant resonant wavelengths in the optical transmission spectrum, acting as the anti-resonant reflecting optical waveguide (ARROW). The modes in two suspended cores and the cladding form the comb pattern. Reliable sensor sensitivity can be obtained by effective experiments and demodulation. Through intensity demodulation of the selected dip of Gaussian fitting, the curvature sensitivity can be up to −7.23 dB/m⁻¹. Through tracking the MZI dip for wavelength demodulation, the temperature sensitivity can be up to 28.8 pm/°C. The sensor is simple in structure, compact, and has good response, which can have a bright application in a complex environment. Full article

(This article belongs to the Special Issue Advanced Infocomm Technology including Selected Papers from 14th ICAIT 2022)

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17 pages, 36817 KiB

Open AccessArticle

Semi-Supervised Deep Learning Model for Efficient Computation of Optical Properties of Suspended-Core Fibers

by Gao Wang, Sufen Ren, Shuna Li, Shengchao Chen and Benguo Yu

Sensors 2022, 22(18), 6751; https://doi.org/10.3390/s22186751 - 7 Sep 2022

Cited by 7 | Viewed by 1908

Abstract

Suspended-core fibers (SCFs) are considered the best candidates for enhancing fiber nonlinearity in mid-infrared applications. Accurate modeling and optimization of its structure is a key part of the SCF structure design process. Due to the drawbacks of traditional numerical simulation methods, such as [...] Read more.

Suspended-core fibers (SCFs) are considered the best candidates for enhancing fiber nonlinearity in mid-infrared applications. Accurate modeling and optimization of its structure is a key part of the SCF structure design process. Due to the drawbacks of traditional numerical simulation methods, such as low speed and large errors, the deep learning-based inverse design of SCFs has become mainstream. However, the advantage of deep learning models over traditional optimization methods relies heavily on large-scale a priori datasets to train the models, a common bottleneck of data-driven methods. This paper presents a comprehensive deep learning model for the efficient inverse design of SCFs. A semi-supervised learning strategy is introduced to alleviate the burden of data acquisition. Taking SCF’s three key optical properties (effective mode area, nonlinear coefficient, and dispersion) as examples, we demonstrate that satisfactory computational results can be obtained based on small-scale training data. The proposed scheme can provide a new and effective platform for data-limited physical computing tasks. Full article

(This article belongs to the Section Optical Sensors)

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7 pages, 2391 KiB

Open AccessCommunication

Fabry-Perot Interferometer Based on Suspended Core Fiber for Detection of Gaseous Ethanol

by Tiago Paixão, Ana Sofia Nunes, Jörg Bierlich, Jens Kobelke and Marta S. Ferreira

Appl. Sci. 2022, 12(2), 726; https://doi.org/10.3390/app12020726 - 12 Jan 2022

Cited by 13 | Viewed by 2302

Abstract

An optical fiber tip sensor based on a Fabry–Perot interferometer is proposed for the detection of ethanol in the gas phase. The sensor is fabricated by fusion splicing one end of the suspended core fiber to a single mode fiber, whereas the other [...] Read more.

An optical fiber tip sensor based on a Fabry–Perot interferometer is proposed for the detection of ethanol in the gas phase. The sensor is fabricated by fusion splicing one end of the suspended core fiber to a single mode fiber, whereas the other end is kept open to enable the interaction between the light propagating in the suspended core and the ethanol gas molecules. The sensor was tested with different percentages of ethanol, exhibiting a linear response between 0 and 100 wt.%, with a sensitivity of 3.9 pm/wt.%. The proposed sensor, with a length of a few hundred micrometers, can be an alternative solution for the detection of gaseous ethanol in foods or beverages, such as wines and distilled drinks. Full article

(This article belongs to the Special Issue Future Foods: Health and Sustainability)

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16 pages, 6919 KiB

Open AccessArticle

Arsenic Sulfide Suspended-core Fiber Simulation with Three Parabolic Air Holes for Supercontinuum Generation

by Tao Peng, Xunsi Wang and Tiefeng Xu

Photonics 2020, 7(3), 46; https://doi.org/10.3390/photonics7030046 - 3 Jul 2020

Cited by 1 | Viewed by 2940

Abstract

Highly nonlinear suspended-core fibers (SCFs) with tunable dispersion have attracted much attention in the fields of Raman amplification, optical frequency combs, broadband and flat supercontinuum generation (SCG). To address the limitation of applications due to its fragile suspension arms, this study proposes the [...] Read more.

Highly nonlinear suspended-core fibers (SCFs) with tunable dispersion have attracted much attention in the fields of Raman amplification, optical frequency combs, broadband and flat supercontinuum generation (SCG). To address the limitation of applications due to its fragile suspension arms, this study proposes the design of a fiber structure with three parabolic air holes. Numerical simulations are performed to optimize an arsenic sulfide SCF in terms of dispersion management and SCG in the wavelength range from 0.6 µm to 11.6 µm. Results show that the proposed SCF has dual zero-dispersion wavelengths (ZDWs) that can be shifted by adjusting the parabolic coefficient of the air-hole and the equivalent diameter of the suspended core. By means of structural optimization, an SCF with 1 μm equivalent diameter and a parabolic coefficient of 0.18 μm⁻¹ is proposed. The first ZDW of the SCF is blue-shifted to 1.541 μm, which makes it possible to use a commercial light source with a cheaper price, more mature technology and smaller volume as the pump source. SCG is studied by solving the generalized nonlinear Schrödinger equation using the split-step Fourier method, and a 0.6–5.0 μm supercontinuum spectrum is obtained at a pump source peak power of 40 kW. Full article

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Graphical abstract

31 pages, 7504 KiB

Open AccessReview

Optical Fiber Sensors Based on Microstructured Optical Fibers to Detect Gases and Volatile Organic Compounds—A Review

by Diego Lopez-Torres, Cesar Elosua and Francisco J. Arregui

Sensors 2020, 20(9), 2555; https://doi.org/10.3390/s20092555 - 30 Apr 2020

Cited by 33 | Viewed by 7236

Abstract

Since the first publications related to microstructured optical fibers (MOFs), the development of optical fiber sensors (OFS) based on them has attracted the interest of many research groups because of the market niches that can take advantage of their specific features. Due to [...] Read more.

Since the first publications related to microstructured optical fibers (MOFs), the development of optical fiber sensors (OFS) based on them has attracted the interest of many research groups because of the market niches that can take advantage of their specific features. Due to their unique structure based on a certain distribution of air holes, MOFs are especially useful for sensing applications: on one hand, the increased coupling of guided modes into the cladding or the holes enhances significantly the interaction with sensing films deposited there; on the other hand, MOF air holes enhance the direct interaction between the light and the analytes that get into in these cavities. Consequently, the sensitivity when detecting liquids, gasses or volatile organic compounds (VOCs) is significantly improved. This paper is focused on the reported sensors that have been developed with MOFs which are applied to detection of gases and VOCs, highlighting the advantages that this type of fiber offers. Full article

(This article belongs to the Special Issue Photonic Crystal Fiber Gas Sensor)

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8 pages, 2037 KiB

Open AccessArticle

Evaluation of Nanoplasmonic Optical Fiber Sensors Based on D-Type and Suspended Core Fibers with Metallic Nanowires

by Diego Santos, Ariel Guerreiro and José Manuel Baptista

Photonics 2019, 6(3), 100; https://doi.org/10.3390/photonics6030100 - 13 Sep 2019

Cited by 6 | Viewed by 3425

Abstract

The introduction of metallic nanostructures in optical fibers has revolutionized the field of plasmonic sensors since they produce sharper and fine-tuned resonances resulting in higher sensitivities and resolutions. This article evaluates the performance of three different plasmonic optical fiber sensors based on D-type [...] Read more.

The introduction of metallic nanostructures in optical fibers has revolutionized the field of plasmonic sensors since they produce sharper and fine-tuned resonances resulting in higher sensitivities and resolutions. This article evaluates the performance of three different plasmonic optical fiber sensors based on D-type and suspended core fibers with metallic nanowires. It addresses how their different materials, geometry of the components, and their relative position can influence the coupling between the localized plasmonic modes and the guided optical mode. It also evaluates how that affects the spatial distributions of optical power of the different modes and consequently their overlap and coupling, which ultimately impacts the sensor performance. In this work, we use numerical simulations based on finite element methods to validate the importance of tailoring the features of the guided optical mode to promote an enhanced coupling with the localized modes. The results in terms of sensitivity and resolution demonstrate the advantages of using suspended core fibers with metallic nanowires. Full article

(This article belongs to the Special Issue Advances on Applications of Optics and Photonics – Selected Papers from the 4th International Conference on Applications of Optics and Photonics, AOP2019)

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20 pages, 14089 KiB

Open AccessReview

Suspended-Core Microstructured Polymer Optical Fibers and Potential Applications in Sensing

by Wanvisa Talataisong, Rand Ismaeel, Martynas Beresna and Gilberto Brambilla

Sensors 2019, 19(16), 3449; https://doi.org/10.3390/s19163449 - 7 Aug 2019

Cited by 23 | Viewed by 7196

Abstract

The study of the fabrication, material selection, and properties of microstructured polymer optical fibers (MPOFs) has long attracted great interest. This ever-increasing interest is due to their wide range of applications, mainly in sensing, including temperature, pressure, chemical, and biological species. This manuscript [...] Read more.

The study of the fabrication, material selection, and properties of microstructured polymer optical fibers (MPOFs) has long attracted great interest. This ever-increasing interest is due to their wide range of applications, mainly in sensing, including temperature, pressure, chemical, and biological species. This manuscript reviews the manufacturing of MPOFs, including the most recent single-step process involving extrusion from a modified 3D printer. MPOFs sensing applications are then discussed, with a stress on the benefit of using polymers. Full article

(This article belongs to the Special Issue Optical Sensors Using Microstructured and Photonics Crystal Fibers)

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15 pages, 4304 KiB

Open AccessArticle

Comparison between Different Structures of Suspended-Core Microstructured Optical Fibers for Volatiles Sensing

by Diego Lopez-Torres, Aitor Lopez-Aldaba, Cesar Elosua, Jean L. Auguste, Rapahel Jamier, Philippe Roy, Manuel Lopez-Amo and Francisco J. Arregui

Sensors 2018, 18(8), 2523; https://doi.org/10.3390/s18082523 - 2 Aug 2018

Cited by 13 | Viewed by 3594

Abstract

In this paper, different core structures of microstructured optical fibers (MOFs) for low-finesse Fabry–Pérot (FP) sensors are experimentally compared to get the highest sensitivity. These devices are designed for volatile organic compounds (VOCs) measurements. Indium tin oxide (ITO) thin films were deposited by [...] Read more.

In this paper, different core structures of microstructured optical fibers (MOFs) for low-finesse Fabry–Pérot (FP) sensors are experimentally compared to get the highest sensitivity. These devices are designed for volatile organic compounds (VOCs) measurements. Indium tin oxide (ITO) thin films were deposited by sputtering on the MOFs and different optical fast Fourier transform (FFT) phase responses from the FP were measured for saturated atmospheres of ethanol. It has been demonstrated that the sensitivities of the developed sensors depend strongly on the geometry and the dimensions of the MOF-cores. The sensors show recovery times shorter than 100 s and the baselines are fully recovered after every exposure to ethanol vapors. Full article

(This article belongs to the Special Issue Novel Sensors Based on Metal Oxide Films and Structures)

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14 pages, 401 KiB

Open AccessReview

Refractive Index Measurement of Liquids Based on Microstructured Optical Fibers

by Susana Silva, Paulo Roriz and Orlando Frazão

Photonics 2014, 1(4), 516-529; https://doi.org/10.3390/photonics1040516 - 8 Dec 2014

Cited by 31 | Viewed by 7556

Abstract

This review is focused on microstructured optical fiber sensors developed in recent years for liquid RI sensing. The review is divided into three parts: the first section introduces a general view of the most relevant refractometric sensors that have been reported over the [...] Read more.

This review is focused on microstructured optical fiber sensors developed in recent years for liquid RI sensing. The review is divided into three parts: the first section introduces a general view of the most relevant refractometric sensors that have been reported over the last thirty years. Section 2 discusses several microstructured optical fiber designs, namely, suspended-core fiber, photonic crystal fiber, large-core air-clad photonic crystal fiber, and others. This part is also divided into two main groups: the interferometric-based and resonance-based configurations. The sensing methods rely either on full/selective filling of the microstructured fiber air holes with a liquid analyte or by simply immersing the sensing fiber into the liquid analyte. The sensitivities and resolutions are tabled at the end of this section followed by a brief discussion of the obtained results. The last section concludes with some remarks about the microstructured fiber-based configurations developed for RI sensing and their potential for future applications. Full article

(This article belongs to the Special Issue Photonic Crystal Sensors)

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12 pages, 1373 KiB

Open AccessArticle

Genotyping Single Nucleotide Polymorphisms Using Different Molecular Beacon Multiplexed within a Suspended Core Optical Fiber

by Linh Viet Nguyen, Sara Giannetti, Stephen Warren-Smith, Alan Cooper, Stefano Selleri, Annamaria Cucinotta and Tanya Monro

Sensors 2014, 14(8), 14488-14499; https://doi.org/10.3390/s140814488 - 8 Aug 2014

Cited by 9 | Viewed by 6195

Abstract

We report a novel approach to genotyping single nucleotide polymorphisms (SNPs) using molecular beacons in conjunction with a suspended core optical fiber (SCF). Target DNA sequences corresponding to the wild- or mutant-type have been accurately recognized by immobilizing two different molecular beacons on [...] Read more.

We report a novel approach to genotyping single nucleotide polymorphisms (SNPs) using molecular beacons in conjunction with a suspended core optical fiber (SCF). Target DNA sequences corresponding to the wild- or mutant-type have been accurately recognized by immobilizing two different molecular beacons on the core of a SCF. The two molecular beacons differ by one base in the loop-probe and utilize different fluorescent indicators. Single-color fluorescence enhancement was obtained when the immobilized SCFs were filled with a solution containing either wild-type or mutant-type sequence (homozygous sample), while filling the immobilized SCF with solution containing both wild- and mutant-type sequences resulted in dual-color fluorescence enhancement, indicating a heterozygous sample. The genotyping was realized amplification-free and with ultra low-volume for the required DNA solution (nano-liter). This is, to our knowledge, the first genotyping device based on the combination of optical fiber and molecular beacons. Full article

(This article belongs to the Special Issue FRET Biosensors)

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12 pages, 2236 KiB

Open AccessArticle

Nanomechanical Optical Fiber with Embedded Electrodes Actuated by Joule Heating

by Zhenggang Lian, Martha Segura, Nina Podoliak, Xian Feng, Nicholas White and Peter Horak

Materials 2014, 7(8), 5591-5602; https://doi.org/10.3390/ma7085591 - 31 Jul 2014

Cited by 8 | Viewed by 6227

Abstract

Nanomechanical optical fibers with metal electrodes embedded in the jacket were fabricated by a multi-material co-draw technique. At the center of the fibers, two glass cores suspended by thin membranes and surrounded by air form a directional coupler that is highly temperature-dependent. We [...] Read more.

Nanomechanical optical fibers with metal electrodes embedded in the jacket were fabricated by a multi-material co-draw technique. At the center of the fibers, two glass cores suspended by thin membranes and surrounded by air form a directional coupler that is highly temperature-dependent. We demonstrate optical switching between the two fiber cores by Joule heating of the electrodes with as little as 0.4 W electrical power, thereby demonstrating an electrically actuated all-fiber microelectromechanical system (MEMS). Simulations show that the main mechanism for optical switching is the transverse thermal expansion of the fiber structure. Full article

(This article belongs to the Special Issue New Materials and Processing Methods for Microstructured Optical Fibres)

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