Optical Cable Research Articles

The Impact of Wiring on Network Reliability in the Aviation Industry

Advancements in networking and embedded systems have played a crucial role in transforming the inflight entertainment and avionics industries over the past few decades. Inflight entertainment relies on various networking applications via these embedded devices like live streaming, video and music streaming from a central server, payment for services, and passenger and crew communications. To understand the network complexity in these aircraft, we need to look at some of the commonly used networking protocols in these applications: ICMP, IP, UDP, TCP, IGMP, ARP, DHCP, and HTTP. A typical commercial aircraft contains many wires, around 150,000 to 500,000, depending on the airline type and size of the aircraft. A lot of modern aircraft use fiber optic cables for high-speed communication. However, copper cables still exist in these aircraft for various reasons. This paper examines the various types of cables used in aircraft and their specific applications. It also highlights potential issues that may impact these cables, focusing on how they can affect network performance. Finally, as a case study, we explore strategies for identifying and addressing problems related to cable bend radius, ensuring a smooth and reliable in-flight entertainment (IFE) experience for passengers. Keywords— Embedded systems, Networks, Network reliability, Cables, Bend radius, Copper, Coaxial, STP, UTP, Fiber optic, Signal integrity, ARP, ICMP, Signal degradation, EMI

Перспективы развития волоконно-оптических систем измерений

Статья посвящена исследованиям в области распределенных и точечных волоконно-оптических измерений (РВОИ и ТВОИ). Представлены результаты этих исследований. Показаны направления разрешения проблем, связанных с одновременным использованием различных возможностей волоконно-оптической техники (ВОТ) для поиска наиболее продуктивных методов и технологий комплексирования антагонистических функций передачи диагностической информации на основе волоконно-оптических линий связи. The article is devoted to research and obtained results related to the field of distributed and point-based fiber-optic measurements based on coherent reflectometry. The necessity of overcoming the following main obstacle is shown: the high sensitivity of the fiber-optic cable laid along the railway track and used as the basis for building a distributed fiber-optic sensor for monitoring train movement parameters to vibroacoustic and seismoacoustic influences exerted during the interaction of wheelsets and rails during the passage of the train, which is the basis for improving the accuracy of optical measurements of train movement parameters, it also becomes an obstacle when transmitting ordinary information packets over other optical fibers of the cable in the mode of transmitting information over an optical communication line. Because of this, various requirements for laying an optical cable also appear: in the first case, as close as possible to the source of vibroacoustic and seismoacoustic effects to increase the sensitivity of distributed fiber-optic sensors, in the second – as far as possible to reduce interference when transmitting information in the optical communication line mode. To solve the existing problems, a method is proposed based on connecting optical coils assembled from optical fiber loops to certain optical fibers of the main optical cable at specified locations. At the same time, to ensure that the results of optical measurements on a distributed sensor are linked to a digital train movement map, the placement of coils is chosen combined with elements of the railway infrastructure that have an accurate geodetic reference. A distinctive feature of the innovations proposed in the article is the possibility of their joint use, which ensures a significant increase in the efficiency of optical measurements.

Using Hybrid LSTM Neural Networks to Detect Anomalies in the Fiber Tube Manufacturing Process

The production process of tubes for fiber optic cables is a complex process, where proper execution is crucial to the quality of the final product. This process has a complex state vector whose structure and coordinates dynamically change during the tube extrusion process. Small fluctuations in process parameters, such as temperature, extrusion pressure, production speed, and optical fiber tension, affect the optical attenuation of the final product. Such defects necessitate the withdrawal of the product. Due to the high number of process coordinates and the technological inability to automatically label those segments of the production process that cause anomalies in the final product, the authors used data clustering methods to create a training set that enabled the use of neural tools for anomaly detection. The system proposed in the main part of the paper includes a hybrid Long short-term memory (LSTM) network model, which is fed with data streams recorded on the tube extrusion production line. The input module, which performs preprocessing of input data, conducts multiresolution analysis of recorded process parameters, and recommends the process state’s belonging to a set of classes describing individual production anomalies to appropriate LSTM network modules. The learning process of the three–channel network allowed effective recognition of five classes of the monitored tube production process. The fit level of the proposed network model reached R2 values of ≥0.85.

Ocean Space Surveillance and Real-Time Event Characterization Using Distributed Acoustic Sensing on Submarine Networks

Abstract Distributed acoustic sensing (DAS) can be deployed on existing submarine fiber-optic cables to add long-range sensor capability to the cable infrastructure. In this article, we present the following: (1) observations and analysis of impulsive source events from long-term DAS measurements on a North Sea submarine telecommunications cable. The observations include local earthquakes originating in the crust below the cable, underwater explosions originating in the water column, an onshore explosion from the nearby coast, and examples of sonic booms from supersonic aircraft and a suspected meteor from the atmosphere. The analysis reveals how the signals from earthquakes and underwater/aerial explosions can be distinguished in the data domain based on their frequency and apparent velocity characteristics. (2) A processing workflow enabling real-time marine surveillance including detection and location of explosions in the water column. The processing is verified by corroborating local earthquakes and underwater explosions with independent data sources. We show that different types of waves can be identified including seismic body waves, hydroacoustic waves, and atmospheric infrasound waves coupled through the water column. Tracking the travel-time moveout along the nonstraight cable route allows for positioning of the source, which we demonstrate by migration stacking of the recorded signal. Signal processing suitable for real-time classification and source location is applied to the recorded data and shows how ocean space surveillance at scale can be realized.

Desain Jaringan Fiber to The Home di Desa Butuh Kidul

This study aims to design a Fiber to the Home (FTTH) network in Butuh Kidul Village, Tengaran District, Semarang Regency. In today's digital era, access to fast and stable internet is a fundamental need for communities. However, many rural areas in Indonesia, including Butuh Kidul Village, still lack adequate internet access. FTTH networks provide a solution by utilizing fiber optic cables that can transmit data at high speeds and with large bandwidth capacity. This research employs the Passive Optical Network (PON) method as the network architecture to enhance efficiency and scalability. The expected outcome is that the local community will benefit from improved internet access, supporting digital village programs and enhancing the quality of life and economic potential. This research is anticipated to serve as a reference for similar network developments in other rural areas.

Improving free space optics performance using QC-LDPC codes and simplified bit flipping decoding in low visibility conditions

Currently, free space optics (FSO) is the most promising technology for achieving high data transfer over short to medium or even long distances. Thus, FSO provides wireless line-of-sight (LOS) connectivity in the unlicensed spectrum and can be a high-bandwidth wireless alternative in contrast to fiber optic cabling. Moreover, the FSO offers rapid assembly times and significant cost savings. However, atmospheric weather (e.g., fog, rain, and snow) can degrade the FSO performance, especially in low visibility conditions. Therefore, this research aims to improve the FSO performance using quasi-cyclic low-density parity-check (QC-LDPC) codes in low visibility scenarios or thick turbulence conditions. In addition, a simplified bit-flipping (SBF) algorithm was proposed to decode the information by the receiver side to minimize complexity. Subsequently, the FSO system is simulated using a 1550 nm laser at different data rates of 1 to 20 Gbps data rate and 1-Watt transmitted power. This paper was analyzed using different empirical models of atmosphere attenuation, like the Kim, Kruse, and Naboulsi models. This simulation also uses modulation techniques such as on-off keying, phase shift keying, and quadrature amplitude modulation. Moreover, the looping iteration number of SBF could improve the system’s performance. We also consider using a low-cost PIN photodetector for practical implementation. Our simulation results show that QC-LDPC codes can achieve an average bit error rate of 10-9 in lower visibility than uncoded information. Our research has significant implications for enhancing fiber optic performance in adverse atmospheric phenomena.

Technological Trends in Plastic Optical Fiber Cables for In-Vehicle Communications

Technological Trends in Plastic Optical Fiber Cables for In-Vehicle Communications

Laboratory Tests Using Distributed Fiber Optical Sensors for Strain Monitoring.

Using fiber optics as a tool for different kinds of geotechnical monitoring can be highly attractive and cost-effective when compared to conventional instruments, such as piezometers and inclinometers, among others. A single fiber optic cable may cover a larger monitoring area compared to conventional instrumentation and allows for monitoring more than one physical quantity with the same fiber optic cable. The literature provides several different examples of distributed fiber optic systems usage. For using any sensor, a calibration curve and parameters are required. In the case of strain sensors, calibration is required to derive strain values from the frequency measurement quantity. However, fiber optic sensor cable manufacturers do not often provide cable calibration parameters, and researchers should consult the specialized literature. This article thus presents a bench adjusted for tests with single-mode fiber optic cables, as well as results of tensile tests for defining the function of strain variations in two different optical fiber cables manufactured by different companies using two different distributed interrogators. This paper also proposes a methodology for calibrating fiber optic cable deformation. A few manufacturers of fiber optic cables aim at civil engineering applications. Therefore, we propose a calibration methodology to show the possibility of obtaining calibration parameters of any fiber optic cable, even those manufactured for telecommunications purposes and not only for cables manufactured for civil engineering use. Thus, researchers will not be restricted to the acquisition of special cables for their applications. The results allowed us to conclude that the application of calibrated fiber optic sensors to experimental pile foundations permits the evaluation of the load-displacement behavior of these elements under different loading conditions.

Structural instability motion and optimization of the demolition and blasting scheme for complex continuous multi-span frame-shear structure

Due to challenges faced during demolition and blasting processes such as conducting prototype monitoring tests on large continuous multi-span structures or carrying out full-area dynamic monitoring of overall structural stress; This paper takes the demolition of the Ruzhou Unicom building as the background, optimizes the design of the demolition and blasting program through theoretical analysis and simulation monitoring, and also studies the form of structural instability movement and the deformation of the key parts of the damage and internal force characteristics, and obtains the following conclusions: the axial force reaches the maximum value when the building is not deflected; when the first-order derivative of the shear force is 0, the maximum shear stress occurs at the position of 2/3 of the height of the building; When the first-order derivative of bending moment is 0, the maximum bending moment occurs at 1/3 of the building height. In Mushroom Pavilion incision formation, the support part of the main structure produces a downward force, exacerbating the disintegration of the main part of the damage; the main structure of the collapse process, the back row of columns are mainly presented as bending shear damage, the upper side beams are mainly presented as tensile damage, the central and lower side beams are mainly presented as compression shear damage. Notably, the bidirectional notch configuration results in a forward displacement of 9.5 meters and a subsequent recoil of 4.6 meters, providing effective shielding for the military fiber-optic cables positioned at the forefront and the adjacent deep excavation pits. Additionally, this configuration facilitates the rapid establishment of a stable collapse pattern between the Mushroom Pavilion structure and its main body, ultimately accelerating the disintegration of the overall building structure during the collapse event.

Listening to Earth’s Subsurface with Distributed Acoustic Sensing

A new book examines how fiber-optic cables installed in boreholes can monitor seismic activity, fluid flow, subsurface temperatures, and more.

Listening to Earth’s Subsurface with Distributed Acoustic Sensing

A new book examines how fiber-optic cables installed in boreholes can monitor seismic activity, fluid flow, subsurface temperatures, and more.

Anchor test and long-term monitoring of grouted anchors instrumented with Fiber Bragg Grating sensing technology

Geotechnical monitoring of anchors provides fundamental data for analysis and evaluation to ensure safe environment. The use of optic fiber sensing technology, especially Fiber Bragg Gratings, brings many advantages of optic fiber sensors, such as high measurement accuracy, real-time continualmonitoring of deformation, on-line access to data and resistance against electromagnetic interferences. This article deals with anchor tests instrumented with FBG deformation gauges of the root and the tendon of the pre-stressed strand anchor in a test field in the Central Bohemian Region. First, the anchor with three optic cables with FBG sensors for measurement of axial deformation was subjected to six loading stages of the anchor test. Most of the sensors measured values of axial deformation less than 200 με and the root mobilisation was observed. Then, the measurement continued by 26-day long-term monitoring and a trend of a small increase of deformations occurred.

Signal quality comparison of customer base and branching methods in fiber to the home network design

One communication medium that is well-known for its outstanding and reliable performance is fiber optic. A social example of its application is the Fiber to the Home (FTTH) network. The goal of this study is to evaluate the signal quality of the customer base method and the branching method, two FTTH-building techniques based on the PT.PLN Icon Plus standards, in order to identify the most practical approach for use in the Air Hitam 2 cluster. Two scenarios were used in this study at the Fiber Access Terminal (FAT) with 1:16 and 1:8 splitters. The fiber optic cable path design findings demonstrate that the branching approach is a wise decision, utilizing optical fiber cables for a total of 9 Km, with the greatest cable distance being 2.5 Km from the Optical Line Terminal (OLT) to the end FAT. According to theory, in the 1:16 splitter situation and the 1:8 splitter scenario, the optical power received by the Optical Network Terminal (ONT) is -19.13 dBm and -16.03 dBm, respectively, with an OLT transmit power of 3 dBm. For these cases, the simulation results are -17.98 dBm and -20.27 dBm. Additionally, the budget value for the rising time reaches 0.253 ns. The bit error rate values in the 1:16 and 1:8 splitter scenarios are 3.157 × 10-10, and 1.63507 × 10-28, respectively, while the Q factor values are 6.18233 and 11.014, respectively. Based on theory and simulation, these findings suggest that the branching strategy can deliver good performance.

ASSEMBLY COUPLING TECHNOLOGY OF MICROLENS ARRAY AND OPTICAL FIBER BUNDLE

Continuous improvements in high-resolution infrared remote sensing imaging technology have led to important applications in various fields; however, the low filling rate of optical fiber and degradation of the focal ratio of the image end remain problems that restrict further development. The coupling technology of the microlens array and optical fiber bundle assembly is the key to solving these problems. In this work, we studied the coupling technology of microlens array and optical fiber bundle assembly. Specifically, six degrees-of-freedom coupling assembly and infrared radiation energy measurement subsystems were built, and based on this a high-precision mechanical alignment coupling efficiency measurement system was designed. After kinematic analysis, it was found that the maximum positioning error was within the allowable error range, making the system suitable for the requirements of precision assembly. Finally, the alignment coupling efficiency of the system was tested, and the results showed that the coupling efficiency reached 92.65%, which was only 6.01% lower than the assumed theoretical value and affirmed the feasibility of the system design for improving the performance of optical fiber image transmission systems.

Leveraging Distributed Acoustic Sensing for monitoring vessels using submarine fiber-optic cables

Leveraging Distributed Acoustic Sensing for monitoring vessels using submarine fiber-optic cables

Immediate and High-Precision Hypocentral Determination for Earthquake Early Warning Applications Using Distributed Acoustic Sensing

ABSTRACT Earthquake early warning (EEW) systems in Japan use data from as little as a single observation point, even at the stage in which only the P wave is detected at one point, to estimate the epicentral distance and magnitude to rapidly issue a warning. This approach aims to maximize lead time but has the drawback of significant estimation errors (epicentral distance: half to double, back azimuth: ±30°). Using distributed acoustic sensing (DAS) with a dense network of observation points allows for rapid and precise earthquake hypocenter determination, significantly reducing estimation errors compared to single-station methods in EEW system. However, no prior studies have investigated the immediacy of using DAS data—which is indispensable for early earthquake warnings. Therefore, we examined the use of DAS for rapid and precise hypocenter determination with the goal of integrating it into the EEW system. We used fiber-optic cables along the Kyushu Shinkansen to analyze strain-rate waveforms, detect P waves, and determine earthquake hypocenter locations. We detected P waves using short-term average /long-term average simultaneously across multiple channels. We then determined the epicenter using Hypomh. For rapid determination of the hypocenter location after P-wave detection, we assessed the hypocenter location each time the number of P-wave detection points increased by 20. For earthquakes with an epicentral distance of less than 50 km, we successfully determined the hypocenter within 12 km of the Japan Meteorological Agency-reported location. This was achieved by identifying the point where the sum of the maximum-likelihood estimation errors was minimized within 2 s of the initial P-wave detection in any channel. The findings suggest that an EEW system using DAS holds potential as a powerful tool to provide rapid and accurate hypocenter information, especially for near-field earthquakes that occur directly beneath populated areas, where lead times are short, and the potential damage is substantial.

A caricaturistic portrait of Ovid from Brigetio (Komárom/Szőny, Hungary)

AbstractIn 2015 a preventive excavation was carried out preceding the laying of an optical cable in close vicinity to the legionary fortress of Brigetio. An otherwise regular Roman terracotta roof tile was found during the excavation, with the image of a bearded man and the inscribed name of Ovidius Naso. The depiction of the poet leans more towards caricature rather than a realistic portrait, but since we do not know of any ancient representations of Ovid, it is of great importance and fits well into the series of other graffiti on roof tiles from Pannonia.

Effect of Seepage on Sand Levee Failure Due to Lateral Overtopping

Recent increases in rainfall duration and intensity due to climate change have heightened the importance of levee stability. However, previous studies on levee failure, primarily caused by seepage and overtopping, have mostly examined these causes independently owing to their distinct characteristics. In this study, we conducted lateral overtopping failure experiments under seepage conditions that closely resembled those in experiments conducted in previous studies. Seepage was monitored using water pressure sensors and a distributed optical fiber cable that provided continuous heat for temperature monitoring in the levee. Τhe analysis of levee failure due to lateral overtopping, in the presence of seepage, was conducted using image analysis with digitization techniques and machine learning-based color segmentation techniques on the protected lowland side of the levee, targeting the same area. The results revealed that levee failure occurred more than twice as fast in experiments where seepage conditions were considered compared to the experiments where they were not. Thus, levees weakened by seepage are more vulnerable to overtopping and breaching. Consequently, employing a comprehensive approach that integrates various monitoring and analysis methods for assessing levee stability is preferable to relying on a single method alone.

High spectral-efficiency, ultra-low MIMO SDM transmission over a field-deployed multi-core OAM fiber

Space-division multiplexing (SDM) systems based on few-mode multi-core fibers (FM-MCFs) utilize both spatial channels (fiber cores) and modes (optical modes per core) to maximize transmission capacity. Unlike laboratory FM-MCFs or field-deployed single-mode multi-core fibers (SM-MCFs), SDM transmissions over field-deployed FM-MCFs in outdoor settings have not been reported. Therefore, concerns remain that environmental interference and cabling stress could worsen inter-core and intra-core modal crosstalk and impact the performance of SDM systems over FM-MCFs. In this paper, we demonstrate successful bidirectional SDM transmission over a 5-km, field-deployed seven ring-core fiber (7-RCF) with a cladding diameter of 178 μm. Our measurements show no significant differences in attenuation and mode coupling compared to pre-cabling conditions, confirming the fiber’s resilience to environmental disturbances and adaptability to cable deployment. Using the field-deployed 7-RCF, bi-directional SDM transmission is implemented, achieving spectral efficiency (SE) of 2×201.6 bit/(s Hz) which sets a new record in field-deployed fiber cables that is a tenfold increase over previous systems. Furthermore, these results were achieved using a small-scale 4×4 multiple-input multiple-output (MIMO) scheme with a time-domain equalization (TDE) tap number not exceeding 15. These results demonstrate the substantial potential of using SDM techniques to significantly enhance SE and expand capacity in practical fiber-optic transmission applications.

A method based on an attention-guided multi-branch residual network for coupled noise suppression in distributed acoustic sensing data

Distributed acoustic sensing vertical seismic profile (DAS-VSP) is an emerging exploration technology. However, the strong energy-coupled noise generated by the vibration of optical cables inside the well casing interferes with the signals collected, reducing the signal-to-noise ratio of seismic data. To address this issue, we have developed a new method based on a U-Net for coupled noise suppression called attention-guided multi-branch residual network (AGMRN). In this method, to capture and enhance multi-scale features of the data, diverse branch blocks (DBB) and convolutional block attention modules (CBAM) are introduced into the U-Net architecture. Additionally, pre-activation residual units (Pre_ARU) are incorporated into the network to reduce the number of parameters in each convolutional layer and improve the efficiency of network training. Furthermore, to ensure the accuracy of the predicted noise, a hybrid loss function combining the L1 norm and Multi-scale structural similarity index measure (MS-SSIM) is employed. The proposed method is based on a large training dataset that includes pairs of data with and without coupled noise. To diversify the noise in the training data, we use the proposed method of synthesizing coupled noise to generate various types of coupled noise. After training the neural network with the training data, the trained network can identify and suppress the coupled noise in DAS-VSP data.