Fiber Optic System Research Articles

Adaptive Multichannel Control for Anti-Aliasing in Fiber-Optic Fabry-Perot Vibration Systems

Adaptive Multichannel Control for Anti-Aliasing in Fiber-Optic Fabry-Perot Vibration Systems

Implementasi dan Pengaruh Time Division Multiplexing (TDM) terhadap Kualitas Transmisi Sinyal

Time Division Multiplexing (TDM) is a multiplexing technique that enables the transmission of multiple signals over a single communication channel by allocating separate time slots for each signal stream. This study aims to analyze the working principles of TDM, examples of its implementation, as well as the benefits and drawbacks of TDM in communication networks. The findings show that TDM can enhance data transmission efficiency through flexible bandwidth allocation, minimizing signal interference and thereby improving signal quality. Due to these advantages, TDM is widely used in fiber optic communication systems, such as telephone and internet networks. Additionally, all data processing is conducted within integrated circuits utilizing Plastic Optical Fiber (POF), allowing TDM to be implemented at a low cost.

Research on intelligent cutting control technology of transverse moving machine for large cross-section roadheader

With the continuous development of the coal mine industry in our country, the cross-section of the roadway is getting larger and larger. The widely used EBZ series roadheader cannot complete the roadway cutting operation with a large cross-section at one time, so it usually needs to move the equipment left and right to complete all its cutting tasks. This paper studies the intelligent control technology of large cross-section roadway cutting, which mainly solves the positioning and attitude determination technology of roadheader in the large cross-section, and offers an accurate shape-cutting control technology and a path planning technology using a lateral moving machine. This paper proposes to combine the signals of laser sensor and fiber-optic inertial navigation system to form a combined positioning and attitude determination system, so as to make use of the advantages and avoid the disadvantages of their respective systems, and improve the accuracy of roadheader positioning and attitude determination. A swing kinematics model of the cutting arm is established, based on which the precise motion control of the first roadway section cutting and the second roadway section cutting can be realized. A key parameter calculation model of roadheader lateral moving machine is put forward to calculate the operation parameters for roadheader lateral moving machine path planning. Finally, the experimental research on intelligent cutting control technology of large cross-section roadheader is carried out in 12307 intelligent heading face of Wangjialing Coal Mine. The results show that the positioning error of the combined positioning and attitude determination system proposed in this paper is between 50-90 mm in the X-axis direction and between 25-45 mm in the Y-axis direction. The average attitude measurement error of heading angle is between 0.5 and 1.5°. This makes the technology appropriate for engineering use. The studied cutting control system achieves a cutting error of 25-50 mm for the first section, and a cutting error of 40-90 mm for the complete section. The complete section cutting error meets the ±100 mm cutting error requirement required in engineering. The intelligent cutting control technology of the lateral moving machine of the large-section tunnel boring machine studied in this paper can realize accurate cutting of the large-section tunnel of 5.6 meters. The research results of this paper provide a reference for the intelligent construction of heading faces.

A Review of Rotational Seismology Area of Interest from a Recording and Rotational Sensors Point of View.

This article reviews rotational seismology, considering different areas of interest, as well as measuring devices used for rotational events investigations. After a short theoretical description defining the fundamental parameters, the authors summarized data published in the literature in areas such as the indirect numerical investigation of rotational effects, rotation measured during earthquakes, teleseismic wave investigation, rotation induced by artificial explosions, and mining activity. The fundamental data on the measured rotation parameters and devices used for the recording are summarized and compared for the above areas. In the section on recording the rotational effects associated with artificial explosions and mining activities, the authors included results recorded by a rotational seismograph of their construction-FOSREM (fibre-optic system for rotational events and phenomena monitoring). FOSREM has a broad range of capabilities to measure rotation rates, from several dozen nrad/s to 10 rad/. It can be controlled remotely and operated autonomously for a long time. It is a useful tool for systematic seismological investigations in various places. The report concludes with a short discussion of the importance of rotational seismology and the great need to obtain experimental data in this field.

A real scale application of a novel set of spatial and similarity features for detection and classification of natural seismic sources from Distributed Acoustic Sensing data

Summary Distributed Acoustic Sensing (DAS) turns a fiber optic into a very dense network of equally-distributed seismic sensors. We focused on the high-density sampling of the seismic wavefield, expressed in strain rates, measured by DAS. Classical approaches used to identify seismic signals rely on the recorded features at one station, but it is difficult to include spatial information in case of dense seismic station networks. This work aims at introducing new spatial and similarity features for seismic event classification suitable to analyze DAS observations. We propose a processing chain based on the XGBoost algorithm and the use of specifically designed spatio-temporal and similarity features for the event classification, and Markov Random Field for the spatial clustering. The methodology is designated to be applied on a continuous stream of DAS observations. We tested our processing chain to detect earthquakes and quarry blasts recorded in the region by permanent seismic networks and included in the RENASS catalog. These events are part of a strain-rate seismic survey carried out during a 3 weeks campaign of DAS measurements along à 91 km fiber optic cable deployed in the central Pyrenees mountains (France). Despite the high anthropogenic activities along the fiber optic path, the proposed method succeeded in detecting earthquakes of magnitude >0.4 and quarry blasts of magnitude >1.0 while limiting the number of false alarms. This performance is particularly noteworthy for low-magnitude events, where detection is accomplished despite a lower signal-to-noise ratio compared to traditional seismometers. The methodology opens the door to real time detection and classification of seismic events measured with long-distance fiber optic systems.

High gain distributed Raman amplifier for orbital angular momentum mode-division multiplexing and wavelength-division multiplexing in a 104-km ring-core fiber over the C + L band

Mode-division multiplexing (MDM) and wavelength-division multiplexing (WDM) are regarded as effective solutions for enhancing the communication capacity of fiber-optic transmission systems. To extend the transmission distance, a suitable amplification technique is required to amplify the signal light, with distributed Raman amplifier (DRA) offering a high-flat gain. In this paper, we experimentally demonstrate the transmission of 3 orbital angular momentum (OAM) mode-division multiplexing and 9 wavelength-division multiplexing ranging from 1530 nm to 1610 nm over a 104-km self-designed ring-core fiber (RCF) with the assistance of DRA. The homemade all-fiber mode selective couplers (MSCs) can (de)multiplex OAM modes (OAM01, OAM11, OAM21) efficiently in long-distance MDM + WDM fiber-optic transmission systems. The OAM-DRA provides high gain (with an on-off gain greater than 10 dB) as well as flat gain (with a differential wavelength gain of less than 0.88 dB and a differential mode gain of less than 0.28 dB) over the C + L band.

Optical Fiber Technology for Efficient Daylighting and Thermal Control: A Sustainable Approach for Buildings

Different direct solar harvesting systems for daylighting are being explored to achieve high uniform illumination deep within buildings at minimal cost. A promising solution to make these systems cost-effective is the use of plastic optical fibers (POFs). However, heat-related issues with low-cost POFs need to be addressed for the widespread adoption of efficient daylighting technologies. Previous studies have explored solutions for this overheating problem, but their effectiveness remains uncertain. This study proposes a low-cost fiber optic daylighting system integrated with a newly patented mechanical component designed to secure the fiber optic bundle at the focal point, providing three levels of heat filtration while ensuring uniform illumination. Our methodology involves selecting a small area, installing the setup, and measuring both heat and light readings, followed by validation through software simulations. The operational principle of this technology is explained, and experimental tests using lux meters and infrared thermometers were conducted to investigate the system’s characteristics. The three-level heat filtration device reduces temperature by approximately 35 °C at the surface of the optical fiber, and the average illumination of the room is around 400 lux. These results were further verified using RELUX simulation software. The findings demonstrate the promising potential of this new device in solar heat filtration and achieving uniform illumination. Recommendations for mitigating overheating damage and exploring heat filtering possibilities in new parabolic solar daylighting systems for further research are also provided.

Performance comparison of different intensity modulation formats for FSO systems

Abstract Intensity modulation (IM) formats are the legacy formats which are continuing to act as modulation formats of interest in fiber optic communication systems and optical networks. The IM formats have become formats of interest in free space optic communication (FSO) systems due to its simple generation and detection principle, thus making FSO system economical and easier to handle/operate under adverse and random characteristics of atmospheric channel. This paper compares the performance of different IM formats (with memory and without memory or memoryless). The IM formats considered here are non return to zero (NRZ), return to zero (RZ), carrier suppressed RZ (CSRZ), vestigial side band CSRZ (VSB-CSRZ), duobinary RZ (DRZ) and modified duobinary RZ (MDRZ). The comparative analysis investigates the effect of launch power and length of FSO channel at different data rates of 10 Gb/s and 40 Gb/s for single channel FSO system, with the help of simulations. The results discussed, depicts that VSB-CSRZ outperforms other modulation formats at 10 Gb/s and duobinary format has shown lesser degradation in system performance when bit rate increases from 10 Gb/s to 40 Gb/s.

Multisource Threatening Event Recognition Scheme Targeting Drone Intrusion in the Fiber Optic DAS System

Multisource Threatening Event Recognition Scheme Targeting Drone Intrusion in the Fiber Optic DAS System

An intelligent and portable fiber optic real-time fluorescence detection system for pathogenic microorganisms detection

The detection of pathogenic microorganisms poses an increasingly serious challenge to food safety. This paper proposes an intelligent fiber optic fluorescence sensing system for detection of pathogenic microorganisms. The system integrates light-emitting diodes and fiber optic sensing arrays. Compact and multi-channel detection is achieved by this kind of design. Environmental parameters such as temperature, humidity, and location are intelligently analyzed together with sampled fluorescence signal, which successfully achieved a high accuracy detection result without affected or interfered by environmental parameters. A Radial Basis Function Neural Network (RBFNN) algorithm is utilized for intelligent analysis and prediction of pathogenic microorganisms’ concentration with environmental parameters. Under different environmental parameters, the system has successfully detected African swine fever virus or salmonella in real-time with high accuracy and sensitivity. Since location of the sensing system can be determined by GPS module integrated in the system, the change of pathogenic microorganisms with different locations can be determined even during transportation. This innovative solution provides a convenient and accurate method for high accurate on-site real time sensing of pathogenic microorganisms.

Investigation of optical soliton solutions for the cubic-quartic derivative nonlinear Schrödinger equation using advanced integration techniques

This paper aims to investigate optical soliton solutions in the context of the cubic-quartic derivative nonlinear Schrödinger equation with differential group delay, incorporating perturbation terms for the first time. Motivated by the need to better understand soliton dynamics in advanced optical communication systems, we employ three integration techniques: the direct algebraic approach, Kudryashov’s method with an addendum, and the unified Riccati equation expansion method. Our study reveals that, by appropriately selecting parameter values, the resulting solutions include Jacobi elliptic functions that describe straddle solitons, bright, dark, and singular solitons. We also identify the conditions under which these soliton pulses can exist. Furthermore, we provide numerical simulations to illustrate these solutions under specific parameter settings, highlighting their potential applications in optical fiber systems.

Experimental Verification of GFRP Bridge Deck Panels Using an Integrated Distributed Fiber Optic Sensing System

Experimental Verification of GFRP Bridge Deck Panels Using an Integrated Distributed Fiber Optic Sensing System

Development of a fiber-optic system for monitoring geotechnical structures

Development of a fiber-optic system for monitoring geotechnical structures

Efficient Light Coupling and Propagation in Fiber Optic Systems

This study explores the propagation of light in optical fibers, focusing on the fundamental principles and practical implications for fiber optic technologies. By analyzing the wave equation, the research demonstrates that light propagates as cylindrical waves within the fiber, contrasting with spherical waves in free space. The study highlights the significance of Gaussian beams, particularly from helium-neon lasers, finding a beam waist radius of approximately 12.6 μm and its position about 1.25 μm from the focus. These parameters are critical for optimizing laser beam coupling into the fiber. The research also measures the light transit time through a 100-meter fiber, revealing a light speed of approximately 2×108 m/sec, which is influenced by the fiber's refractive index. Additionally, the relationship between diode laser output power and injection current was investigated, demonstrating a linear correlation crucial for practical applications. The findings emphasize the importance of accurate measurements and configuration in improving fiber optic communication and laser performance. This comprehensive analysis provides valuable insights into the design and optimization of optical fiber systems, contributing to advancements in communication and laser technologies.

A Study on Sensitivity Improvement of the Fiber Optic Acoustic Sensing System Based on Sagnac Interference.

A new pickup structure was introduced and modified to improve the resolution of the linear Sagnac optical fiber acoustic sensing system. The maximum strains corresponding to the material, diameter, wall thickness, and height of the pickups were analyzed by simulation. An aluminum cylinder with a diameter of 110 mm, a wall thickness of 3 mm, and a height of 120 mm was chosen as the basic pickup. A four-groove pickup with a vertical width of 80 mm and a horizontal width of 20 mm was introduced to improve the sensitivity of the system. The experiments showed that the average peak-to-peak sensitivity of the four-groove pickup increased by 215.54% to 106.806 mV/Pa. The improved pickup can be applied in areas to monitor the situation of invasion of the Sagnac optical fiber acoustic sensing system.

Experimental Study of Surface Microtexture Formed by Laser-Induced Cavitation Bubble on 7050 Aluminum Alloy

In order to study the feasibility of forming microtexture at the surface of 7050 aluminum alloy by laser-induced cavitation bubble, and how the density of microtexture influences its tribological properties, the evolution of the cavitation bubble was captured by a high-speed camera, and the underwater acoustic signal of evolution was collected by a fiber optic hydrophone system. This combined approach was used to study the effect of the cavitation bubble on 7050 aluminum alloy. The surface morphology of the microtexture was analyzed by a confocal microscope, and the tribological properties of the microtexture were analyzed by a friction testing machine. Then the feasibility of the preparation process was verified and the optimal density was obtained. The study shows that the microtexture on the surface of a sample is formed by the combined results of the plasma shock wave and the collapse shock wave. When the density of microtexture is less than or equal to 19.63%, the diameters of the micropits range from 478 μm to 578 μm, and the depths of the micropits range from 13.56 μm to 18.25 μm. This shows that the laser-induced cavitation bubble is able to form repeatable microtexture. The friction coefficient of the sample with microtexture is lower than that of the untextured sample, with an average friction coefficient of 0.16. This indicates that the microtexture formed by laser-induced cavitation bubble has a good lubrication effect. The sample with a density of 19.63% is uniform and smooth, having the minimum friction coefficient, with an average friction coefficient of 0.14. This paper provides a new approach for microtexture processing of metal materials.

Improving the Performance of Bidirectional Communication System Using Second-Order Raman Amplifiers

In order to achieve low-cost scalability, the same-wavelength bidirectional (SWB) fiber communication system is a better solution. We present a detailed investigation of the performance of the different orders Raman amplifiers in same-wavelength bidirectional fiber communication systems. We discuss how to suppress the main factor affecting system performance which is Rayleigh scattering noise (RSN). By using different Raman amplifiers to construct different quasi-lossless transmission, the performance changes in the same-wavelength bidirectional fiber optic communication system were studied. On this basis, multi-channel and same-wavelength single fiber bidirectional system experiments were conducted to compare the performance of second-order Raman systems and first-order Raman systems. The results indicate that the Rayleigh scattering suppression effect of second-order Raman systems is better, and compared to first-order Raman systems, the average signal-to-noise ratio (SNR) can be increased by 2.88 dB.

Acoustic emission and multiscale computation-guided tensile damage identification in woven composite laminates at cryogenic temperatures as low as 20 K

For laminated composite structures as key components of storage tanks serving at cryogenic temperature, it is crucial to identify the damage mechanisms for evaluating their mechanical properties and guiding structural design. In this work, the cryogenic tensile damage behavior of a thin-walled woven composite laminate was investigated through the acoustic emission (AE) monitoring and multiscale finite element (FE) computation at typical low temperatures of 153 K, 77 K and 20 K. We first established temperature-dependent constitutive laws for the microscale and mesoscale constituents of such composites based on experimental data, followed by the development of a hierarchical computational framework for modeling multiscale damage characteristics at different low temperatures. A fiber-optic acoustic emission measurement system was constructed to provide online monitoring of tensile damage of the woven composite laminates at cryogenic temperatures as low as 20 K. The comparations were made between the predicted cryogenic damage characteristics and in-situ AE signal analysis, assisted by scanning electron microscope (SEM) observations. The computed cryogenic damage evolution closely matched the AE signal identification results. The results indicate that fiber breakage and matrix cracking are the dominant cryogenic damage modes, and that the different low temperatures exert significant effects on the properties of the epoxy matrix, yarns and composite laminates. The combination of the AE monitoring system and the computational scheme provides a valuable tool for evaluating structural integrity and guiding the microstructural design of composite laminates used in cryogenic environments.

The Zero-Velocity Correction Method for Pipe Jacking Automatic Guidance System Based on Fiber Optic Gyroscope.

The pipe jacking guidance system based on a fiber optic gyroscope (FOG) has gained extensive attention due to its high degree of safety and autonomy. However, all inertial guidance systems have accumulative errors over time. The zero-velocity update (ZUPT) algorithm is an effective error compensation method, but accurately distinguishing between moving and stationary states in slow pipe jacking operations is a major challenge. To address this challenge, a "MV + ARE + SHOE" three-conditional zero-velocity detection (TCZVD) algorithm for the fiber optic gyroscope inertial navigation system (FOG-INS) is designed. Firstly, a Kalman filter model based on ZUPT is established. Secondly, the TCZVD algorithm, which combines the moving variance of acceleration (MV), angular rate energy (ARE), and stance hypothesis optimal estimation (SHOE), is proposed. Finally, experiments are conducted, and the results indicate that the proposed algorithm achieves a zero-velocity detection accuracy of 99.18% and can reduce positioning error to less than 2% of the total distance. Furthermore, the applicability of the proposed algorithm in the practical working environment is confirmed through on-site experiments. The results demonstrate that this method can effectively suppress the accumulated error of the inertial guidance system and improve the positioning accuracy of pipe jacking. It provides a robust and reliable solution for practical engineering challenges. Therefore, this study will contribute to the development of pipe jacking automatic guidance technology.

MODELLING OF A TBPS SYSTEM FOR 5G WIRELESS COMMUNICATION UTILIZING DWDM RFoF

In recent times, several sectors and businesses have been doing extensive research on the usage of Dense Wavelength Division Multiplexing (DWDM) and Radio Frequency Over Fiber (RFOF). These two technologies are considered to be the most significant features. Increasing the data rate was a significant challenge that needed to be addressed, and the goal was to successfully implement a fiber optic system that was dependable and had a high number of associated channels. As a consequence of this, a 64-channel DWDM RFOF system that is capable of supporting a larger number of data rates of 2.56 Tbps has been designed and implemented in this study. A significant number of channels that have been sampled will be chosen for inquiry based on the characteristics of Quality Factor (QF) and Bit Error Rate (BER) that have been researched. This study will be carried out with the assistance of Optisystem software. These findings would be investigated at distances ranging from sixty to one hundred eighty kilometers, with the NRZ modulation format being used and a lunched power of zero decibels per meter. Additionally, the purpose of this study would be to explore the three distinct techniques of compensation, namely pre, post, and symmetrical, to quantify the individual performance of each approach on the suggested system. According to the findings, the use of symmetrical-based compensation yielded the most favorable outcomes, with the average QF produced falling within the range of (20.33-14.09) dBm over distances ranging from (60-180) kilometers. This demonstrates the dependability of the proposed system.