Optical Cable Research Articles

Some challenges in using multilayer networks to bridge brain and mind.

The application of techniques from network science to create single-layer networks of the brain and mind has resulted in significant advances in the neuro- (i.e., structural and functional brain networks) and cognitive sciences (i.e., cognitive network science). Recent advances in network science on multilayer networks increase the possibility that a "network of networks" might finally connect the physical brain to the intangible mind, much like physical fibre optic cables and wires connect to other layers of the internet to allow intangible social networks to form in various social media platforms. Several advances in structural brain networks, functional brain networks, cognitive networks, and multilayer networks are briefly reviewed. The possibility that these single-layer networks can be connected in a multilayer network to connect the brain to the mind is discussed, as well as some of the challenges that face such an ambitious endeavour. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Degradation effects in FRNC jackets of optical fiber cables

Degradation effects in FRNC jackets of optical fiber cables

New Measuring and Data Transmission Equipment for Operational Oceanography at the Gelendgik Black Sea Test Site of Institute of Oceanology of the RAS

The design and principles of operation of the bottom multi-modem station MDS-II, located in the coastal zone (depth of location — 25 m) of the northeastern part of the Black Sea at the Gelendzhik Test Site of IO RAS are described. The station is connected to the coastal center by means of a bottom fiber-optic cable, through which power is supplied to the station, and online transmission of measurement data takes place. The station is an underwater server to which one can connect a measuring device and get a real-time access to it, as well as remotely control on its operation. The design of an automatic stationary station for vertical sounding (SSVS) of water column, which is also used at the Gelendzhik Test Site, is also described. This station is installed close to the MDS-II multi-modem station and is connected to one of its modems. The station consists of a bottom electric winch installed on the seabed and a floating module (probe) on a cable line wound around the winch drum. When the command ʺsoundingʺ is given, the cable unwinds and the floating module, equipped with temperature and pressure sensors, floats and measures the water temperature profile from the bottom layer to the sea surface. Then the cable is winding on a drum, and the floating module returns to the bottom layer. A prototype of a new SSVS is being developed, which will allow sounding of the water layer with a thickness of up to 100 m. It will be equipped with a multi-parameter probe that makes joint measurements of hydrophysical and bio-optical parameters.

Optimalisasi Infrastruktur Jaringan dengan Teknologi Fiber Optic di PT. Sinar Nusantara Industries

PT. Sinar Nusantara Industries is a manufacturing company that produces famous building materials. One of the important divisions in the company's operations is the Information Technology (IT) division that is responsible for network infrastructure. Currently, the company uses UTP cables for the network, but the distant inter-building distance leads to connectivity instability. To address this problem, the study proposes replacing the UTP cable with fiber optics from the server room to the finished product warehouse (GPJ) to improve the network infrastructure at PT. Sinar Nusantara Industries. This research uses the PPDIOO method (Prepare, Plan, Design, Implement, Operate, Optimize) to ensure each step is done in a structured manner. Research results show that the use of fiber optic cables increases network speeds from 100 Mbps to 300-500 Mbps and improves the stability and reliability of remote connections. The implementation also utilizes fast connectors to facilitate connectivity without splicing, making it more effective. Thus, this move is expected to improve network performance and security in PT. Sinar Nusantara Industries

Polarization sensing of network health and seismic activity over a live terrestrial fiber-optic cable

Wide-scale sensing of natural and human-made events is critical for protecting against environmental disasters and reducing the monetary losses associated with telecommunication service downtime. However, achieving dense sensing coverage is difficult, given the high deployment overhead of modern sensor networks. Here we offer an in-depth exploration of state-of-polarization sensing over fiber-optic networks using unmodified optical transceivers to establish a strong correlation with ground truth distributed acoustic sensing. To validate our sensing methodology, we collect 85 days of polarization and distributed acoustic sensing measurements along two colocated, 50 km fiber-optic cables in Southern California. We then examine how polarization sensing can improve network reliability by accurately modeling overall network health and preemptively detecting traffic loss. Finally, we explore the feasibility of wide-scale seismic monitoring with polarization sensing, showcasing the polarization perturbations following low-intensity earthquakes and the potential to more than double seismic monitoring coverage in Southern California alone.

Direction-Finding Study of a 1.7 mm Diameter Towed Hydrophone Array Based on UWFBG.

This paper investigates a 1.7 mm diameter ultra-weak fiber Bragg grating (UWFBG) hydrophone towed array cable for acoustic direction finding. The mechanism of the underwater acoustic waves received by this integrated-coating sensitizing optical cable is deduced, and it is shown that the amplitude of its response varies with the direction of the sound wave. An anechoic pool experiment is carried out to test the performance of such a hydrophone array. The test array is a selection of six sensing fibers, each of which is coiled into 9 cm diameter fiber ring suspended in the water to receive acoustic signals. An average sensitivity of -141.2 dB re rad/μPa at frequencies from 2.5 kHz to 6.3 kHz was achieved, validating the detection of the azimuth of underwater acoustic waves. The ultra-thin towing cable system, with free structure, high sensitivity, and underwater target-detection capability has demonstrated great potential for future unmanned underwater vehicle (UUV) applications.

Heated fibre optics to monitor soil moisture under successive saturation–drying cycles: An experimental approach

AbstractIn recent decades, distributed temperature sensing (DTS) has emerged as a robust technology for environmental applications, enabling high‐resolution temperature measurements along fibre optic cables (FOCs). The actively heated fibre optic (AHFO) method is employed to monitor soil moisture (, m3 m−3), wherein the soil temperature subsequent to the application of a heat pulse is measured by a DTS (AHFO‐DTS approach). Despite significant improvements in the application of AHFO‐DTS under controlled and natural conditions, the thermal behaviour of soil during multiple saturation–natural drying cycles has been insufficiently evaluated. This study aimed to address this gap by constructing an experimental horizontal soil profile in the laboratory for the application of the AHFO‐DTS method during two successive saturation–drainage–evaporation (SDE) cycles. Three heating strategies were applied to a metallic alloy in contact with a FOC, and calibration models were used to correlate with the thermal conductivity (), cumulative temperature increase (), and maximum temperature increase (). The results indicated that during the second SDE cycle, the highest errors in estimates were observed with the low power‐short heat pulse, whereas the application of the low power‐long duration and high power‐short duration pulses improved the accuracy of calculations. Additionally, errors in estimates escalated under wetter conditions, attributed to a shift in soil heat transfer capacity from the first to the second SDE cycle for > 0.10 m3 m−3. This behaviour was ascribed to thermal hysteresis, arising from the contact resistance of the FOC and the alloy with the surrounding soil. Furthermore, the method exhibited the least sensitivity to this effect and yielded reliable estimates, thus its adoption is recommended. Moreover, the use of the low power‐long duration heating strategy is suggested as it promotes a trade‐off between energy saving and accurate estimates. We concluded that assessing soil thermal response under multiple SDE cycles enhances the comprehension of the AHFO‐DTS method. Overall, our findings provide insights into enhancing the applicability of this approach under field conditions, particularly following irrigation schedules and natural rainfall events.

Investigation of Mixed-Mode Crack Quantification with Distributed Fiber Optic Sensors

The development of high-resolution distributed fiber optic sensing (DFOS) technologies, particularly optical frequency domain reflectometry (OFDR), has proven effective in measuring crack widths. However, most existing research assumes that the crack opening direction is perpendicular to the cable direction, with limited studies addressing mixed-mode cracks using distributed fiber optic sensors. This research aims to create a novel method for quantifying mixed-mode cracks using DFOS, combining experimental investigations and numerical simulations. A calibration rig was designed and fabricated to simulate mixed-mode crack conditions in a 2D plane, allowing for the reproduction of various crack opening scenarios. Multiple fiber optic cable types with distinct strain transfer mechanisms were used, crossing the artificial crack surface at varying angles. The mechanical behavior of fiber optic cables in mixed-mode crack situations was further examined through numerical simulations. Based on findings from both experimental and numerical studies, an algorithm was developed to determine crack width and crack opening direction using DFOS data. As mixed-mode cracks frequently occur in reinforced concrete structures under complex stress conditions, this research enhances the understanding of fiber optic sensor performance in realistic cracking situations and offers valuable insights for more precise damage assessment using DFOS.

Sensing with submarine optical cables

Sensing with submarine optical cables

Multi-parameter information detection of aircraft taxiing on an airport runway based on an ultra-weak FBG sensing array

Tracking the moving state and analyzing the distribution feature of an aircraft taxiing on the pavement are crucial for runway safety management. One challenge is to provide a reliable methodology that would enable such needs to be addressed in long-distance range runway with high sensitivity and spatial resolution. This paper proposed a novel monitoring approach for acquiring multi-parameter information of aircraft taxiing on airport runway based on distributed vibration detected by ultra-weak fiber Bragg grating (FBG) sensing array. For an actual engineering equipped with the smart runway system, the ultra-weak FBG sensing technology was applied to collect the distributed vibration responses of taxiing aircraft in takeoff and landing stages. The monitoring data of the vibration sensing optical cables beneath the entire pavement were directly utilized to evaluate the identification feasibility and effectiveness of taxiing speed and position, landing distribution, and taxiing acceleration and distance based on samples of five representative aircraft types. The results indicated that the speed, position, aiming point offset, acceleration changes and probability distribution of the taxiing distance can be revealed based on actual measurements concerning the distribution of vibration intensity with respect to space and time. Moreover, the analysis demonstrated that the experimental results based on ultra-weak FBG sensing array was able to account for the characteristic of different aircraft types participating in the study and the current operating conditions of the airport.

Application of Distributed Acoustic Sensing in Geophysics Exploration: Comparative Review of Single-Mode and Multi-Mode Fiber Optic Cables

The advent of fiber optic technology in geophysics exploration has grown in its use in the exploration, production, and monitoring of subsurface environments, revolutionizing the way data are gathered and interpreted critically to speed up decision-making and reduce expense and time. Distributed Acoustic Sensing (DAS) has been increasingly utilized to build relationships in complex geophysics environments by utilizing continuous measurement along fiber optic cables with high spatial resolution and a frequency response of up to 10 KHz. DAS, as fiber optic technology examining backscattered light from a laser emitted inside the fiber and measuring strain changes, enables the performance of subsurface imaging in terms of real-time monitoring for Vertical Seismic Profiling (VSP), reservoir monitoring, and microseismic event detection. This review examines the most widely used fiber optic cables employed for DAS acquisition, namely Single-Mode Fiber (SMF) and Multi-Mode Fiber (MMF), with the different deployments and scopes of data used in geophysics exploration. Over the years, SMF has emerged as a preferred type of fiber optic cable utilized for DAS acquisition and, in most applications examined in this review, outperformed MMF. On the other side, MMF has proven to be preferable when used to measure distributed temperature. Finally, the fiber optic cable deployment technique and acquisition parameters constitute a pivotal preliminary step in DAS data preprocessing, offering a pathway to improve imaging resolution based on DAS measurement as a future scope of work.

Effects of angle of incidence of stimulus light on photopic electroretinograms of zebrafish larvae

In electroretinographic (ERG) recordings of zebrafish, the light stimulus is usually delivered by a fiber optic cable. The purpose of this study was to determine whether the angle of incidence of the stimulus light from the fiber optic cable will affect the amplitudes and implicit times of the ERGs of zebrafish larvae. The larvae were positioned on their side with the right eye pointed upward. The light stimuli were delivered by a fiber optic cable from three directions of the larvae: frontal 0° (F0°), dorsal 30°(D30°), and ventral 30°(V30°). Photopic ERGs were recorded from 16 larvae at age 5–6 days post-fertilization. Our results showed that the mean amplitude of the b-wave elicited at D30° and V30° stimulation was significantly smaller than that elicited at F0° stimulation (P = 0.014 and P = 0.019, respectively). In addition, the mean amplitude of the d-wave elicited at D30° and V30° stimulation was significantly smaller than that elicited at F0° stimulation (P < 0.0001 and P = 0.015, respectively). However, the difference between the b-wave amplitudes elicited at D30° and V30° stimuli were not significant (P = 0.98), and the d-wave amplitudes were also not significantly different (P = 0.20). The average b-wave amplitudes elicited at D30° stimulation was 84.6 ± 15.7% and V30° stimulation was 84.8 ± 17.4% relative to that of F0° stimulation. The average d-wave amplitudes elicited by D30° stimulation was 85.5 ± 15.2% and by V30° stimulation was 79.0 ± 11.0% relative to that of F0° stimulation. The differences in the implicit times of the b- and d-wave elicited by the different directions of stimulation were not significant (P = 0.52 and P = 0.14, respectively). We conclude that the amplitude of the photopic ERGs is affected by the angle of the incident light. Thus, it would be better to use ganzfeld stimuli to elicit maximum b- and d-wave amplitudes of the photopic ERGs of zebrafish larvae.

A Review of Subsidence Monitoring Techniques in Offshore Environments.

In view of the ever-increasing global energy demands and the imperative for sustainability in extraction methods, this article surveys subsidence monitoring systems applied to oil and gas fields located in offshore areas. Subsidence is an issue that can harm infrastructure, whether onshore or especially offshore, so it must be carefully monitored to ensure safety and prevent potential environmental damage. A comprehensive review of major monitoring technologies used offshore is still lacking; here, we address this gap by evaluating several techniques, including InSAR, GNSSs, hydrostatic leveling, and fiber optic cables, among others. Their accuracy, applicability, and limitations within offshore operations have also been assessed. Based on an extensive literature review of more than 60 published papers and technical reports, we have found that no single method works best for all settings; instead, a combination of different monitoring approaches is more likely to provide a reliable subsidence assessment. We also present selected case histories to document the results achieved using integrated monitoring studies. With the emerging offshore energy industry, combining GNSSs, InSAR, and other subsidence monitoring technologies offers a pathway to achieving precision in the assessment of offshore infrastructural stability, thus underpinning the sustainability and safety of offshore oil and gas operations. Reliable and comprehensive subsidence monitoring systems are essential for safety, to protect the environment, and ensure the sustainable exploitation of hydrocarbon resources.

Enhanced frequency and time domain feature extraction for communication infrastructure type classification using optical fiber sensing

We present a feature extraction method for a feedforward-type neural network (FNN) designed to realize a distributed acoustic sensing (DAS) technique that suits conventional optical fiber. This is, to the best of our knowledge, the first trial in which an FNN is used to interpret the field communication infrastructure type surrounding optical cables. Three classes are taken to represent the field environment: the cable tunnel (class 1), circular duct (class 2), and overhead area (class 3). We investigate and compare frequency- and time-domain feature extraction. We also show that the frequency-domain features yielded by spectral envelope shape (SES) processing have better performance than simple fast Fourier transform features. Two types of time-domain features are verified: one is the short-time maximum magnitude (STMM), which shows the largest value in the time frame, and the other is the short-time average magnitude (STAM), which indicates the average value in a time frame. Note that all features are optimized for multi-class classification. In this paper, we present the suitable number of both features and the number of training iterations. An accuracy rate of 79.0% is achieved using FNN analysis with the features studied here. Furthermore, by considering the similarity of neighboring classes, classes are refined into higher probability classes. As a result, accuracy is improved to 87.2%.

Rethinking the Roughness Height: An Improved Description of Temperature Profiles over Short Vegetation

In this study, we present an extension to the Monin–Obukov similarity theory (MOST) for the roughness sublayer (RSL) over short vegetation. We test our theory using temperature measurements from fiber optic cables in an array-shaped set-up. This provides a high vertical measurement resolution that enables us to measure the sharp temperature gradients near the surface. It is well-known that MOST is invalid in the RSL as the flow is distorted by roughness elements. However, to derive the surface temperature, it is common practice to extrapolate the logarithmic profiles down to the surface through the RSL. Instead of logarithmic behaviour defined by MOST near the surface, our observations show near-linear temperature profiles. This log-to-linear transition is described over an aerodynamically smooth surface by the Van Driest equation in classical turbulence literature. Here we propose that the Van Driest equation can also be used to describe this transition over a rough surface, by replacing the viscous length scale with a surface length scale Ls\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$L_s$$\\end{document} that represents the size of the smallest eddies near the grass structures. We show that Ls\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$L_s$$\\end{document} scales with the geometry of the vegetation and that the model shows the potential to be scaled up to tall canopies. The adapted Van Driest model outperforms the roughness length concept in describing the temperature profiles near the surface and predicting the surface temperature.

Assessing the Expansion of Ground-Motion Sensing Capability in Smart Cities via Internet Fiber-Optic Infrastructure

Abstract Monitoring ground motion in smart cities can improve the public safety by providing critical insights on natural and anthropogenic hazards, for example, earthquakes, landslides, explosions, infrastructure failures, and so forth. Although seismic activity is typically measured using dedicated point sensors (e.g., geophones and accelerometers), techniques such as distributed acoustic sensing have demonstrated the utility of using fiber-optic cable to detect seismic activity over comparable distances. In this article, we present the results of a study that quantifies the expansion in an area monitored for low-amplitude ground-motion events by augmenting existing point sensors with the internet fiber-optic cable infrastructure. We begin by describing our methodology, which utilizes geospatial data on point sensors and internet optical fiber deployed in metropolitan statistical areas (MSAs) in the United States. We extend these data to identify the area that can be monitored by (1) considering the observed seismic noise data in target locations, (2) applying the model from Wilson et al. (2021) to understand the potential coverage area gains using optical fiber sensing, and (3) optimizing the selection of fiber segments to maximize coverage and minimize deployment costs. We implement our methodology in ArcGIS to assess the additional area that can be monitored for low-amplitude ground-motion events (i.e., magnitude &amp;gt;0.5) by utilizing internet fiber-optic cables in the 100 most populous MSAs in the United States. We find that the addition of internet fiber-based sensors in MSAs would increase the area monitored on average by over an order of magnitude from 1% to 12%, if the subset of fiber cable segments that maximize coverage and minimize deployment costs is chosen even if only 20% of all fibers are used.

Experimental study on joint sensing and early warning method of landslide disaster based on NPR-OFST

In order to explore more effective methods of landslide disaster monitoring and controlling, NPR anchor cable and optical fiber grating strain sensor are physically combined to form a slope reinforcement-monitoring integration system, with PVC pipe an intermediary. Physical model test is carried out according to timely warning of landslide disasters of the Newtonian force monitoring system. At the same time, the optical fiber sensing technology has the condition of continuous perception of time and space. The feasibility of monitoring the whole life cycle of slope instability and positioning the potential sliding surface is discussed. Through the analysis of the test results, it is concluded that the fiber grating strain sensor can effectively monitor the deep displacement of the slope. PVC pipe and the soil have deformation coordination, which is able to effectively reinforce the slope body together with the combined anchor cable sensing device, and can continuously sense the potential sliding surface in the whole life cycle of the slope. By comparing the results of Newton force monitoring curve with the fiber grating strain monitoring, the mechanical law of “Newton force sudden drops, immediately catastrophe happens” is further verified. The feasibility of the combined sensing and early warning method of optical fiber sensing technology and Newton force monitoring is verified. This method realizes the further optimization of Newton force monitoring system.

Near-surface characterization using shear-wave resonances: A case study from offshore Svalbard, Norway

Shear-wave (S-wave) resonances are typically observed when the surficial marine sediments over a rock substrate have relatively low S-wave velocities. We observe these phenomena using ocean-bottom fiber-optic distributed acoustic sensing (DAS) in two subsea fiber-optic telecommunication cables in Svalbard, Norway. Strong seismic energy from sufficiently large earthquakes is required to trigger and enhance the multiple-order modes of S-wave resonances. Here, we use the interpreted S-wave resonance frequencies of the first two modes to determine the thickness and the S-wave velocity of the near-surface low-velocity layer (LVL) beneath the seafloor. In addition, we use existing active P-wave seismic reflection data to determine the LVL thickness and to help build a more accurate S-wave velocity model from the S-wave resonance frequencies. The estimated S-wave velocity varies laterally within the LVL formation. Here, we find that the sediments or deposits with high S-wave velocity presented in the estimated LVL model agree with the distribution of some glacigenic sediments and landforms deposited in the survey area. Therefore, S-wave resonances measured by ocean-bottom DAS can be used to characterize the corresponding near-surface LVLs.

A microporous framework with aromatic pores for one-step purification of C2F6 from CF3CH2F/CF3CHF2/C2F6 mixture

Separating C2F6 from CF3CH2F/CF3CHF2/C2F6 is of great importance since electronic grade C2F6 is an important plasma etching gas that can be used for surface cleaning of electronic devices, as well as microelectronics, fiber optic cables and solar cells. Herein, a four-fold intermingled MOF material Ni(pba)2 was constructed, which has a high selectivity of CF3CH2F/C2F6 (38.8) and CF3CHF2/C2F6 (19.8). Breakthrough experiments show that high-purity C2F6 can not only be obtained from the binary CF3CHF2/C2F6 (5/95, v/v) and CF3CH2F/C2F6 (5/95, v/v) mixtures but also can be directly collected from ternary CF3CH2F/CF3CHF2/C2F6 (5/5/90, v/v/v) mixture with a high productivity of 7.1 mol/kg. Additionally, it is found that Ni(pba)2 can maintain good separation performance under different conditions. Finally, the theoretical calculation results show that the interactions between C2F6 and the aromatic pores are significantly lower than those of CF3CHF2 and CF3CH2F, which leads to good C2F6 separation performance.

Implementation of e-Government via Lapak Aduan Banyumas

The purpose of this writing is to assess the community participation in Kabupaten Banyumas in utilizing E-Government media, analyze the supportive and inhibiting factors in the implementation of E-Government, and evaluate the efforts made by the Kabupaten Banyumas Government in overcoming these challenges. This qualitative research involves a literature review. The research process includes gathering primary and secondary literature sources, data processing, citation extraction, and abstraction to present research findings. Interpreting these findings generates comprehensive information, leading to knowledge acquisition for conclusive insights. The results of the discussed research reveal that Lapak Aduan Banyumas is an effective and efficient communication medium between the community and local government through social media, enhancing community participation in politics. Besides, uneven network infrastructure, particularly inadequate transmission towers and fiber optic cables in the hilly areas of Kabupaten Banyumas, results in unsatisfactory website-based service delivery.