Types Of Optical Fibers Research Articles

A light-weight neural network for marine acoustic signal recognition suitable for fiber-optic hydrophones

Fiber-optic hydrophones based on optical fiber sensing and communication technology have developed rapidly in recent years. With the advantages of high sensitivity, small size, and large dynamic range, they are easy to detect underwater acoustic signals, showing great potential in the field of marine ecological protection. Researchers can monitor the marine ecological environment by recognizing underwater optical fiber sensing signals collected by fiber-optic hydrophones in real-time. Deep learning models can achieve high recognition accuracy, but they usually have large amounts of parameters that makes them difficult to be deployed in mobile terminals of marine survey ships. To solve the key problem, this paper discussed the design of the Deep Light-Weight Attention Residual Network (DLA-ResNet). It introduces the depth-wise separable convolution (DSC) and the convolutional block attention module (CBAM) into ResNet18 to make its performance better. ResNet18 is a two-dimensional convolutional network (CNN) model applying residual blocks. Experiments verify that the accuracy of DLA-ResNet improved from ResNet18 is increased by about 2.04% and its size is reduced by 85.67%. The proposed scheme in this paper realizes an average recognition rate of 96.50% for eight types of underwater optical fiber sensing signals in the application of marine ecological environment monitoring. Moreover, its model size is only 6.12 MB and it only takes 27.90 ms, which is available to meet the needs of reliability and effectiveness.

Impact of Illuminated Road Signs on Driver’s Perception

This study determined citizens’ perceptions and impact factors of illuminated road signs installed to ensure their visibility at night when the risk of traffic accidents is high. An ordered logit model was used to measure illuminated road signs’ impact on drivers’ perception based on the data from the citizens’ survey conducted by the Road Sign Center. According to the results, the internal (optical fiber) type variable had the highest impact, followed by the frequent fog variable and the complex road line variable. This study found that most citizens positively recognized road signs, preferred internal (optical fiber) types, and desired illuminated road signs that considered climate, environment, and road structure types. In Seoul, the importance and improvement of illuminated road signs at points where road structures are complex, such as city streets, were high. Additionally, the illuminated road sign recognition and road type variable were significant in Gyeonggi-do, which reflected the high number of citizens that commute to Seoul from Gyeonggi-do. Concerning local cities and counties and intercity roads highly affected by the climate, the impact was high at points with frequent fog. Fog affects the visibility distance, generates condensation on signs, and significantly degrades visibility. Therefore, an illuminated road sign installation method must be presented based on spatial analysis for regions vulnerable to climate, environment, and road location. Additionally, the road intersection point variable was significant in local cities and counties, which reflects the relatively lagged road infrastructure. Local cities and counties are financially poor and have numerous aged drivers; hence, central government support that considers these aspects is crucial.

Design mode filtering interferometer using etched double clad fiber

Abstract Mode filtering technique is one of the most desired techniques in optical fiber communication systems, especially for multiple input multiple output (MIMO) coherent optical communications that have mode-dependent losses in communication channels. In this work, a special type of optical fiber sensing head was used, where it utilizes DCF13 that is made by Thorlabs and has two numerical apertures (NA’s). One is for core and 1st cladding region, while the 2nd relates the 1st cladding to the 2nd cladding. Etching process using 40 % hydro-fluoric (HF) acid was performed on the DCF13 with variable time in minutes. Investigation of the correlation between the degree of etching and the refractive index (RI) profile of double-clad fibers for low order linearly polarized (LP) modes is the focus of this work research. The used software programs to simulate the effect of etching are Comsol Multi-Physics V6 and Optigrating V4.2.2. It is seen that the optimum case that gave highest cladding power to core power ratio is the case of etching for 10 min, which can be used for detection applications. This ratio greatly affects the sensitivity of the system.

Simultaneous measurement three parameters of temperature, strain, and curvature by thin-core fiber based-Mach-Zehnder interferometer

A Mach-Zehnder interferometer (MZI) sensor for simultaneous measurement of three parameters is developed. The sensor structure is spliced by single-mode fiber, no-core fiber, thin-core fiber (TCF) and single-mode fiber in turn, where the sensing element is TCF. Due to the different core diameters of three types of optical fibers, the light in the transmission process excites a number of higher-order modes and interacts to form a mode interferometer. The interference spectrum produces many resonance peaks that are sensitive to different parameters. We select three resonant peaks sensitive to temperature, strain and bending for measuring temperature, strain and curvature. The experimental results display that the resonant wavelength of the sensor transmission spectrum drifts linearly as a function of the environmental parameters, with a maximum sensitivity of 248.7 pm/℃ for temperature, −2 pm/με for strain and −24.784 nm/m−1 for curvature. Selecting three resonance peaks to construct a measurement matrix realizes three-parameters simultaneous measurement and eliminates the cross-sensitivity among the three physical quantities. In addition, the proposed sensor possesses appealing characteristics of facile manufacturing process, compact size, high sensitivity, good linear fitting, robustness and low cost, and the sensor has a broad application prospect in the field of multi-parameter simultaneous measurement. In short, only one MZI in the optical fiber can realize the simultaneous monitoring of temperature, strain and bending, which provides a new solution for creating a compact multi-parameter sensor for structural health monitoring.

Wearable Optical Fiber Sensors for Biomechanical Measurement in Medical Rehabilitation: A Review

With the increasing demand for rehabilitation of the elderly population and patients with limb injuries, it is imperative to develop new wearable health monitoring system and assistive rehabilitation equipment. Optical fiber sensing has the advantages of light-weight, anti-electromagnetic interference, higher strain and elastic limit, safety and dependableness. It has been significantly utilized in engineering prospecting, building structure monitoring, and medical and health fields. At present, the application of optical fiber sensing in medical rehabilitation has been developed rapidly, however, the discussion and summary of its key theories and technologies are insufficient. This review details different types of optical fiber sensing mechanisms and devices, as well as the measurement of physical parameters using optical fiber sensors and application examples in the field of medical rehabilitation. This review systematically analyzes the advance of the sensitivity, flexibility, accuracy, and wearability of the optical fiber sensing in the monitoring of human body sign information. This review also discusses the challenges of making a new generation of optical fiber sensors that fit human joints, muscles, and rehabilitation equipment. Finally, this review provides a research direction for the realization of flexible, comfortable, safe, stable monitoring of human biomechanical parameters and real-time precise control of rehabilitation equipment in the future.

Graphene Oxide Doped Alginate Coated Optical Fiber Sensor for the Detection of Perfluorooctanoic Acid in Water

A novel and easy to fabricate graphene doped alginate thin film (Alg /GO) capable of binding with perfluorooctanoic acid (PFOA) and working on the principle of a Fabry-Perot interferometry (FPI) type optical fiber sensor is presented here. Utilizing a simple dip coating technique, the Alg/GO coating was deposited on the freshly cleaved fiber end-face followed by cross-linking in calcium chloride. The experimental results from two independent data analysis techniques, including Fourier-transform infrared (FTIR) spectroscopy and analytical adsorption tests were used to confirm that the developed graphene doped alginates can adsorb PFOA. It was also found that GO doped alginate coating adsorbs twice as much PFOA compared to alginate alone. Similarly, experimental results of the developed FPI sensor demonstrate the sensitivity to PFOA in aqueous solutions with a limit of detection (LOD) of 0.4 ppb and a non-linear correlation between 0 to 2 ppb with increasing concentration of PFOA in water. The response time at this concentration was estimated to be 17 s, considering a thin film coating thickness of approximately 30 μm as determined via imaging with the aid of differential interference contrast (DIC) microscopy. The relatively high sensitivity and ease of formation of the coating offers the potential for future development of portable optical sensors for emerging environmental contaminants.

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 Comparative Study of Plastic and Glass Optical Fibers for Reliable Home Networking

Home networking using fiber optics is essential for uninterrupted data transmission in modern communication networks. In this study, we evaluated and compared the reliability of plastic optical fibers (POFs) and glass optical fibers (GOFs) for home networking applications. Furthermore, assess the advantages and disadvantages of POF and GOF over short distances and find that POF is more suitable for home network applications due to its higher reliability. In addition, it has the advantage of being cost-effective and flexible for short-distance applications. The results show that POF indicates higher reliability and better performance at 8.25517 × 101of the Q factors, 2.21355 × 10−3 of the eye height, and 2.8307 × 10−3 of the threshold values at 30 meters, while GOF shows 6.30 × 101 of the Q factor, 3.78087 × 10−3 of the eye heights and 4.34736 × 10−3 of the threshold values. Moreover, this research highlights the importance of reliability in designing and applying optical fiber networks and can help network designers and engineers make informed decisions when selecting the appropriate type of optical fiber for specific applications.

Strain Monitoring of Overhead Transmission Line Based on Brillouin Scattering

The change in the optical fiber state and the status of transmission line often leads to the change of strain in its composite optical fiber. This paper attempts to use a commercial BOTDR (Brillouin optical time-domain reflectometry) to monitor the strain of optical fiber composited in transmission line. The Brillouin spectra of typical optical fiber used in the transmission line are measured by a commercial BOTDR at room temperature, the spectra are fitted and the key parameters are calculated, and then the strain along whole optical fiber is obtained by demodulation. The results show that BOTDR can effectively monitor the optical fiber strain, and the mean standard deviation of strain measured for multiple measurements under the same condition is only about 8 με, which can stastify the requirements of practical cases. The work of this paper lays a foundation for the strain measurement of transmission line.

Low‐Temperature Synthesis of Silicon Oxynitride‐Doped Si for Tunable Bragg Gratings Homogeneously Deposited on Si, SiO2, and Borosilicate Substrates and the tip of SM and PM Optical Fibers

AbstractOptical tunability and repeatability are essential in fabricating optoelectronic devices from waveguides to Bragg gratings (BGs) for high‐energy, high‐power, mode‐locking, and sensing applications. For this purpose, a controlled adjustment in the optical properties, including the refractive index of the deposited nanolayers, becomes critical. This study reveals that silicon oxynitride (SiON) doping into silicon (Si) offers a new way for the preparation of novel Si‐based devices with an emphasis on the BGs for filtering a particular portion of an electromagnetic spectrum, including the wavelengths of 800, 976, 1550, and 1840 nm. Control on the incident angle dependence of the BGs is demonstrated at Watt‐level for the wavelength of 976 nm. Amorphous SiON‐doped Si layers on alternating SiO2 can be synthesized on bulk substrates and different optical fibers at relatively low temperatures with wide and narrow bandwidths. The high reflectivity of the novel Si‐based BGs reveals over −22 dB reflection using typical optical fibers, including standardsingle‐mode fibers and high‐birefringent polarization‐maintaining (PM) fibers. The polarized transmission measurement over the BG on the PMfiber shows the BGs do not deteriorate the PM properties, strongly yielding a beat length of 1.68 mm and birefringence of 9.2 × 10−4 at the telecom C band.

Temperature Dependence of Radiation-Induced Attenuation of a Fluorine-Doped Single-Mode Optical Fiber at Infrared Wavelengths

Harsh environments can combine radiations and extreme temperature constraints, which can both degrade the optical performances of silica-based optical fibers. Among the different types of optical fibers, the ones having a core in pure-silica or doped with Fluorine are known to present, generally, the lowest steady state radiation-induced attenuation (RIA) to high cumulated doses (> 10 kGy) at room temperature. In this work, we investigate how the RIA levels and kinetics of a radiation hardened F-doped single-mode optical fiber depend on the irradiation temperature. To achieve this, we performed a systematic study on the combined temperature (from -80°C to 80°C) and steady state X-ray radiation (up to 100 kGy) effects on a F-doped single-mode fiber with a high temperature acrylate coating in the infrared domain. We then discuss the basic mechanisms at the origin of the RIA and its temperature dependence.

Имитационная программа для оценки влияния нелинейных фазовых искажений на показатели качества сигналов в оптическом тракте

The influence of nonlinear phase interference of self-phase modulation and phase cross-modulation arising in an optical fiber on multichannel, spectrally separated signals is considered. A simulation program has been created in the environment of the object-oriented programming language C#, which makes it possible to calculate the BER in the receiving part depending on the parameters of the optical path. The program has several degrees of freedom in the following parameters: transmission rate, used linear signal code, optical power level in individual channels, length and type of optical fiber. It is shown that in order to achieve the required BER, it is necessary to limit the optical power levels in the channel signals. The results of simulation of signal transmission over a distance of 100 km for the number of channels 40, 80 and 160 with channel rates of 10 Gbit/s and 40 Gbit/s in NRZ and RZ linear codes are presented.

The Optimization of Multimode Fiber Speckle Sensor for Microvibration

A vibration sensing system with optical fiber speckles is demonstrated and optimized with different optical fiber diameters and speckle statistical algorithms. The types of fiber diameter and material lead to a different performance of fiber specklegram sensor (FSS), which has been experimentally explored. The signal intensity, demodulated from the speckles, is different when using multimode fibers with different diameters. At the same time, the sensing effect of different fibers depends on the speckle statistical algorithms. Accordingly, we use different statistical methods in theory and experiment to analyze the influence of fiber diameter and speckle statistical methods on the sensing performance. A vibration sensing system with optimized performance is achieved by the optimized types of optical fiber and the corresponding optimized algorithms, which are promising for sensing weak vibration, such as detecting.

Solution of fiber Raman amplifier model using binary search equation-based adaptive artificial bee colony algorithm

Due to the need for high bandwidth, there is growing interest in distributed fiber Raman amplifiers (FRA). In addition to having wide bandwidth, FRAs have the advantages of a low noise factor and simplicity of use. However, the optimization of the wavelength and power values of the pump lasers to be used in FRAs for a broadband and flat gain region is an important problem to be solved. In this study, a distributed FRA system was set using 100 signals with a 50-km propagation distance and 8 pump signals in the opposite direction, which were gain-flattened. The attenuation coefficient of SMF-28 type optical fiber was used in the system. First, optimum pump wavelengths and power levels were found by the binary search equation based adaptive artificial bee colony algorithm. Then, the FRA boundary value problem (BVP) was solved with the MATLAB BVP solver. Finally, the analytical Jacobian matrix required for the solution of the equation was included in the system, and faster and more effective results were obtained. The results show that the gain ripple of 100 optical signals was 0.5 dB at the maximum.

Exploring specialty optical fiber for astrophotonics applications

Photonics technology has the potential for applications in space environment which is helpful in studying and analyzing various parameters of space. This integration of space and photonics technology is called Astrophotonics. Various types of Specialty Optical Fibers (SOF) have been designed for specific applications. The SOFs have capacity to sense high temperature as well as a wide range of radiation. These fibers are enabled for multi-point and real-time monitoring of temperature as well as radiation parameters. We have proposed the implementation of such specialty optical fibers as sensors for space vehicles. Also, SOFs that can be utilized for other parameters sensing have been discussed in this paper.

Simulation study of Dual-Readout Calorimeter for a forward calorimeter at the Electron-Ion Collider

The Electron-Ion Collider (EIC) is a future particle accelerator to be built at the Brookhaven National Laboratory, and the primary purpose of experiments at the EIC is to resolve the question of partonic structure of nucleons and nuclei. To achieve the physics goals of the EIC, a hadron calorimeter of high energy resolution is required at forward rapidity. A Dual-readout Calorimeter (DRC) which has been developed for future collider experiments is considered as an upgrade option of the forward hadron calorimeter for the ECCE experiment at the EIC. The DRC consisting of two types of optical fiber, Cherenkov and Scintillation fibers, can achieve high energy resolution by measuring a fraction of electromagnetic shower in a hadronic shower. A performance study of DRC for the EIC such as geometry, material, and energy resolution is ongoing based on the existing simulation framework for high energy experiments, and the DRC simulation details will be transported to the EIC simulation framework. In this presentation, we will introduce the simulation study of the DRC for the EIC.

ВЫЯВЛЕНИЕ РАЗНОВИДНОСТЕЙ ОДНОМОДОВЫХ ОПТИЧЕСКИХ ВОЛОКОН И ОПРЕДЕЛЕНИЕ ХАРАКТЕРИСТИК ИХ ПРОДОЛЬНОГО НАТЯЖЕНИЯ

This paper presents the results of studies on the automation of the processing of measurements of Brillouin reflectograms containing various types of single-mode optical fibers. By analyzing the Mandelstam-Brillouin scattering parameters, it is possible to distinguish the varieties of optical fibers in the studied optical cables, as well as to estimate the change in Brillouin frequency shift and determine the degree of longitudinal tension. The initial values of the Brillouin frequency shift and the Mandelstam-Brillouin scattering spectrum for each type of optical fiber differ. Developed programs for processing Blilluen reflectograms are presented. Conclusions were made about the accuracy of estimates obtained according to various algorithms, based on the accumulated experience in working with the presented programs.

Fiber-Agnostic Machine Learning-Based Raman Amplifier Models

In this paper, we show that by combining experimental data from different optical fibers, we can build a fiber-agnostic neural-network to model the Raman amplifier. The fiber-agnostic NN model can predict the gain profile of a new fiber type (unseen by the model during training) with a maximum absolute error as low as 0.22 dB. We show that this generalization is only possible when the unseen fiber parameters are similar to the fibers used to build the model. Therefore, a training dataset with a wide range of optical fibers parameters is needed to enhance the chance of accurately predicting the gain of a new fiber. This implies that time-consuming experimental measurements of various fiber types can be avoided. For that, here we extend and improve our general model by numerically generating the dataset. By doing so, it is possible to generate uniformly distributed data that covers a wide range of optical fiber types. The results show that the averaged maximum prediction error is reduced when compared to the limited experimental data-based general models. As the second and final contribution of this work, we propose the use of transfer learning (TL) to re-train the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">numerical data-based</i> general model using just a few experimental measurements. Compared with the fiber-specific models, this TL-upgraded general model reaches very similar accuracy, with just 3.6% of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">experimental data</i> . These results demonstrate that the already fast and accurate NN-based RA models can be upgraded to have strong fiber generalization capabilities.

Polymer tapered pillar on a fiber end fabricated by UV irradiation using a high-NA fiber

The increasing need for single-mode fibers (SMFs) and advances in silicon photonics (SiPh) devices have led to the need for an efficient method of optical coupling between them. To achieve a higher coupling between them, a polymer tapered pillar was fabricated on the end face of the SMF by applying the optical diffraction effect and a self-written waveguide technology using a high numerical aperture (HiNA) fiber. The initial 10.4 µm spot size was reduced to 4.17 µm at 1.55 µm wavelength, and the greatest coupling efficiency of –1.01 dB was reached between an SMF with a tapered pillar and uncured resin cladding and a HiNA fiber. Full Text: PDF ReferencesR. Marchetti, C. Lacava, L. Carroll, K. Gradkowski, P. Minzioni, "Coupling strategies for silicon photonics integrated chips [Invited]", Photonics Res. 7, 201 (2019). CrossRef R. Bachelot, C. Ecoffet, D. Deloeil, P. Royer, D.-J. Lougnot, "Integration of micrometer-sized polymer elements at the end of optical fibers by free-radical photopolymerization", Appl. Opt. 40, 5860 (2001). CrossRef P. Pura, M. Szymanski, M. Dudek, L.R. Jaroszewicz, P. Marc, M. Kujawinska, "Polymer Microtips at Different Types of Optical Fibers as Functional Elements for Sensing Applications", J. Lightwave Techn. 33, 2398 (2015). CrossRef O. Mikami, R. Sato, S. Suzuki, C. Fujikawa, "Polymer Microlens on Pillar Grown From Single-Mode Fiber Core for Silicon Photonics", IEEE Photonics. Technol. Lett. 32, 399 (2020). CrossRef Y. Kamiura, T. Kurisawa, C. Fujikawa, O. Mikami, "High optical coupling efficiency of polymer microlens and pillar on single mode fiber for silicon photonics", Jpn. J. Appl. Phys. 61, SK1009 (2022). CrossRef F. Tan, H. Terasawa, O. Sugihara, A. Kawasaki, T. Yamashita, D. Inoue, M. Kagami, C. Andraud, "Two-Photon Absorption Light-Induced Self-Written Waveguide for Single-Mode Optical Interconnection", J. Lightwave Tech. 36, 2478 (2018). CrossRef H. Terasawa, O. Sugihara, "Near-Infrared Self-Written Optical Waveguides for Fiber-to-Chip Self-Coupling", J. Lightwave Technol. 39, 7472 (2021). CrossRef K. Vanmol, K. Saurav, V. Panapakkam, H. Thienpont, N. Vermeulen, J. Watté, J. Van Erps, "Mode-field Matching Down-Tapers on Single-Mode Optical Fibers for Edge Coupling Towards Generic Photonic Integrated Circuit Platforms", J. Lightwave Tech. 38, 4834 (2020). CrossRef Y. Saito, K. Shikama, T. Tsuchizawa, H. Nishi, A. Aratake, N. Sato, "Tapered Self-Written Waveguide between Silicon Photonics Chip and Standard Single-Mode Fiber", Opt. Fiber Communication Conference (OFC2020), paper W1A.2, (2020). CrossRef Y. Saito, K. Shikama, T. Tsuchizawa, N. Sato, "Tapered self-written waveguide for a silicon photonic chip I/O", Opt. Lett. 47(12), 2971 (2022). CrossRef N.A. Baharudin, C. Fujikawa, O. Mitomi, A. Suzuki, S. Taguchi, O. Mikami, S. Ambran, "Tapered Spot Size Converter by Mask-Transfer Self-Written Technology for Optical Interconnection", Photon. Technol. Lett. 29, 949 (2017). CrossRef H. Nawata, K. Ohmori, Proc. International Conference on Electronics Packaging (ICEP), paper 23 (2014) DirectLink S. J. Frisken, "Light-induced optical waveguide uptapers", Opt. Lett. 18, 1035 (1993). CrossRef Y. Obata, Y. Oyama, H. Ozawa, T. Ito, O. Mikami, T. Uchida, "Multi-array Self-written Waveguides using Photo-mask for Optical Surface Mount Technology", International Conference on Electronics Packaging (ICEP), paper 225 (2005). DirectLink P. Yin, J.R. Serafini, Z. Su, R. Shiue, E. Timurdogan, M.L. Fanto, S. Preble, "Low connector-to-connector loss through silicon photonic chips using ultra-low loss splicing of SMF-28 to high numerical aperture fibers", Opt. Expr. 27, 24188 (2019). CrossRef https://coherentinc.force.com/Coherent/UHNA3?cclcl=en_US, (18/09/2022). DirectLink

Comparison of existing and new optical fiber-based scintillation detectors for spent-fuel verification equipment

The Wolsung Nuclear Power Plant in Korea is under IAEA safeguards. During IAEA physical inventory verifications, the Optical Fiber radiation Probe System has been used since 2007 as the official instrument for verification of spent fuel. Its low sensitivity requires excessive time and labor to perform the IAEA safeguard activities and increases the operator load for preparing a dangerous and time-consuming secondary inspection. The objective of this paper is to develop a superior new optical fiber-based scintillation detector to deal with such issues. To increase the sensitivity of the instrument, a new optical fiber-based scintillation detector was developed by combining a p-terphenyl scintillator with a new type of optical fiber. A field test was carried out in the CANDU Wolsung Unit 1 to characterize the performance of the new detector. The field test showed that the OFPS using the new optical fiber-based scintillation detector has at least 100-times higher sensitivity and can also measure even very weak signals not measurable by the existing detector. From the experimental results, we can conclude that the newly developed OFPS detector would increase the effectiveness and efficiency of nuclear safeguards for verification of spent fuel in wet storage pools of CANDU reactors.