Optical Fiber Research Articles

Long-distance transmission conductor condition sensing based on distributed fiber optic sensing technology

Abstract The existing long-distance transmission line perception mainly focuses on the measurement and analysis of electrical parameters. When the line is subject to wind vibration, icing or galloping, the changes of electrical parameters are not obvious and difficult to capture, resulting in poor performance of long-distance transmission line fault state perception. In this regard, the long-distance transmission line condition sensing based on distributed optical fiber sensing technology is studied. This method designs corresponding sensing methods for four working conditions: using the back Brillouin scattering sensor and phase sensitive Rayleigh scattering sensor in the optical fiber sensing technology to form a multi parameter distributed optical fiber sensing device, which is used to sense the surface temperature, vibration, strain and other data of the long-distance transmission line; By analyzing the linear relationship between fiber Brillouin frequency shift and Brillouin power and fiber strain and temperature, the sensing results of icing thickness of long-distance transmission lines are obtained; By calculating the amplitude and phase information of the detection signal, the sensing results of long-distance transmission line vibration are obtained; By calculating the time difference of polarization mutation signal at both ends of long-distance transmission line, combined with the propagation speed of optical signal and the length of long-distance transmission line, the perception result of lightning fault location of long-distance transmission line can be obtained. The experimental results show that this method can more accurately collect the real-time operation data of long-distance transmission lines, and can effectively perceive the galloping, wind vibration and lightning fault location of long-distance transmission lines.

Fundamental study on performances of fiber-superconducting composite CORC cable: Electromagnetic, thermal, mechanical and quench behaviors

Abstract Common terminal voltage measurement can be hardly applied to detect quenches in long high temperature superconducting (HTS) conductor on round core (CORC) cable because not only the HTS normal zone propagation velocity (NZPV) is low but also immobilizing a large number of voltage leads is inconvenient. Distributed optical fiber sensing (DOFS) technology is a promising method for quench detection of long superconductors. To sense the thermal changes of CORC cables during quenches more directly and prevent optical fibers from damages by external stress, a fiber-superconducting composite (FSC) CORC cable was fabricated. For this cable, three optical fibers were placed in three grooves of the copper core respectively, then three HTS tapes were spirally wound on the copper core in sequence. Comparing to a traditional CORC cable, obviously, the FSC CORC cable structure has been changed. To promote FSC CORC cable engineering applications, it is necessary to study the fundamental performance of the cable. In this paper, we investigated the electromagnetic, thermal and mechanical properties of the FSC CORC cable by comparing those with a common one. The results demonstrated that, compared to the common one, the magnetic distribution of the FSC CORC cable hardly changed, but the current distribution of the copper core in the FSC CORC cable slightly changed which led to decreases of transport AC loss, in addition, the thermal characteristics of the FSC CORC cable was slightly changed and the bending tolerance ability of the cables reduced within a bending diameter range of 15 cm. What’s more, the embedded optical fibers combined with a distributed optical fiber sensing (DOFS) system are successfully used to detect the temperature changes of the cable surface. Finally, to study the quench behaviors of the cable, we built a quench detection platform, which equips with a voltage acquisition system, a thermocouple temperature acquisition system and the DOFS system. By using the platform to detect the quenches of the FSC CORC cable, minimum quench energy (MQE) of the cable and NZPV of the tape and cable at different currents was tested.

Optical gain and related proerties of GaSbN/GaSb quantum-well laser: numerical approach

Currently, lasers are still of ongoing interest. They are used in a large range of practical applications in our day life and across various fields. Utilizations include industry such as in cutting, welding, drilling, and engraving of various materials, in medicine such as in surgery for precise cutting and cauterization with minimal tissue damage, in ophthalmology, dentistry for removing tooth decay and reshaping dental tissues, in high-speed data transmission through optical fibers, in science and research (spectroscopy, metrology and holography) and for creating visual displays, etc. The optical gain of a laser diode is a key characteristric that exhibits the performances of lasers. In the present work, we investigated the optical gain of a strained GaSbN/GaSb quantum well laser with nitrogen concentration of 3%. This low nitrogen concentration makes our GaSbN alloy a dilute one. Our analysis focused on the impact of carrier density and quantum well width on optical gain of the laser device being studied. Additionally, we determined the relationship between quantum well width and emitted wavelength. Our numerical results indicate an effective correlation between optical gain and both carrier density and quantum well width. Furthermore, inasing the quantum well width led to a longer emitted wavelength. The laser demonstrated emission within the infrared-red spectrum.

Optical fibre based artificial compound eyes for direct static imaging and ultrafast motion detection

Natural selection has driven arthropods to evolve fantastic natural compound eyes (NCEs) with a unique anatomical structure, providing a promising blueprint for artificial compound eyes (ACEs) to achieve static and dynamic perceptions in complex environments. Specifically, each NCE utilises an array of ommatidia, the imaging units, distributed on a curved surface to enable abundant merits. This has inspired the development of many ACEs using various microlens arrays, but the reported ACEs have limited performances in static imaging and motion detection. Particularly, it is challenging to mimic the apposition modality to effectively transmit light rays collected by many microlenses on a curved surface to a flat imaging sensor chip while preserving their spatial relationships without interference. In this study, we integrate 271 lensed polymer optical fibres into a dome-like structure to faithfully mimic the structure of NCE. Our ACE has several parameters comparable to the NCEs: 271 ommatidia versus 272 for bark beetles, and 180o field of view (FOV) versus 150–180o FOV for most arthropods. In addition, our ACE outperforms the typical NCEs by ~100 times in dynamic response: 31.3 kHz versus 205 Hz for Glossina morsitans. Compared with other reported ACEs, our ACE enables real-time, 180o panoramic direct imaging and depth estimation within its nearly infinite depth of field. Moreover, our ACE can respond to an angular motion up to 5.6×106 deg/s with the ability to identify translation and rotation, making it suitable for applications to capture high-speed objects, such as surveillance, unmanned aerial/ground vehicles, and virtual reality.

A Comprehensive Exploration of Contemporary Photonic Devices in Space Exploration: A Review

Photonics plays a pivotal role in propelling space exploration forward, providing innovative solutions to address the challenges presented by the unforgiving and expansive realm of outer space. Photonic-based devices, encompassing technologies such as lasers, optical fibers, and photodetectors, are instrumental in various aspects of space missions. A notable application is in communication systems, where optical communication facilitates high-speed data transfer, ensuring efficient transmission of information across vast interplanetary distances. This comprehensive review unveils a selection of the most extensively employed photonic devices within the realm of space exploration.

Continuous GPS PPP-AR frequency transfer links

Abstract In this paper, we show that the SPARK software of the Natural Resources Canada (NRCan) with their DCR (Decoupled Clock Rapid) products can be used to generate the PPP-AR continuous batch clock solutions of multiple days, which we use to build frequency transfer links between two remotely located GPS receivers. The reliability and confidence in forming the long-term frequency transfer links have been improved compared to reference~\cite{jian2023gps}. We compare the SPARK PPP-AR links to an optical fiber and TWSTFT links for hundreds of days. The ∽500-day-long comparisons with TWSTFT show no frequency bias for continental and cross-continental links. Frequency transfer links formed using the SPARK solutions have uncertainty of 1×10-15/T, where T is in days, without reaching the noise floor, a critical requirement for comparing optical frequency standards and for the redefinition of the SI second. The short latency of the NRCan DCR products enables the quick availability of the PPP-AR links presented in this paper marking it particularly relevant for time sensitive applications.

New Angular Momentum Conservation Laws for Electromagnetic Waves Interacting with Dirac fields

Abstract Global conservation laws of angular momentum are well-known in the theory of light-matter interaction. However, local conservation laws, i.e. the conservation law of angular momentum at every point in space, remain unexplored especially in the context of relativistic Dirac-Maxwell fields. Here, we use the QED Lagrangian and Noether's theorem to derive a new local conservation law of angular momentum for Dirac-Maxwell fields in the form of the continuity relation for linear momentum. We separate this local conservation law into four coupled motion equations for spin and orbital angular momentum (OAM) densities. We introduce a helicity current tensor, OAM current tensor, and spin-orbit torque in the motion equations to shed light on the local dynamics of spin-OAM interaction and angular momentum exchange between Maxwell and Dirac fields. We elucidate how our results translate to classical electrodynamics using the example of plane wave interference as well as a dual-mode optical fiber. Our results shine light on angular momentum phenomena related to the relativistic interaction of electromagnetic waves and Dirac fields.

Rogue-wave structures for a generalized (3+1)-dimensional nonlinear wave equation in liquid with gas bubbles

Abstract This study explores the behavior of higher-order rogue waves within a (3+1)-dimensional generalized nonlinear wave equation in liquid-containing gas bubbles. It creates the investigated equation's Hirota $D$-operator bilinear form. We employ a generalized formula with real parameters to obtain the rogue waves up to the third order using the direct symbolic technique. The analysis reveals that the second and third-order rogue solutions produce two and three-waves, respectively. To gain deeper insights, we use the Cole-Hopf transformation on the transformed variables $\xi$ and $\eta$ to produce a bilinear equation. Using system software \textit{Mathematica}, the dynamic analysis presents the graphics for the obtained solutions in transformed $\xi, \eta$ and original spatial-temporal coordinates $x,y,z,t$. These visualizations reveal rogue waves' intricate structure and evolution, capturing their localized interactions and significant presence within nonlinear systems. We demonstrate that rogue waves, characterized by their substantial height and sudden appearance, are prevalent in various nonlinear events. The equation examined in this study offers valuable insights into the evolution of longer waves with smaller amplitudes, which is particularly relevant in fields such as fluid dynamics, dispersive media, and plasmas. The implications of this research extend across multiple scientific domains, including fiber optics, oceanography, dusty plasma, and nonlinear systems, where understanding the behavior of rogue waves is crucial for both theoretical and practical applications.

Photonic generation and transmission of dual-band double-TBWP chirped microwave waveforms with frequency multiplication and immunity to dispersion-induced power fading

A novel photonic approach for generating and transmitting dual-band double-time bandwidth product (TBWP) chirped microwave waveforms with frequency multiplication and immunity to dispersion-induced power fading is proposed. Utilizing an integrated dual-drive dual-parallel Mach-Zehnder modulator (DD-DPMZM), single-sideband modulation of the RF input and suppression of odd-order optical sidebands are achieved. By adjusting the RF input's centre frequency and the DD-DPMZM's bias voltages, dual-band waveforms with frequency multiplication are realized, enabling transmission through optical fibres without dispersion-induced power fading. Experimental validation demonstrates successful transmission over dispersion compensation modules equivalent to 60 km or 20 km of single-mode fibre. The proposed system features a simplified architecture, reconfigurability, and robust anti-dispersion capabilities, making it highly suitable for distributed multi-band radar networks over optical fibre links.

Reliability of two-dimensional steady magnetized Jeffery fluid over shrinking sheet with chemical effect

Abstract A numerical framework is established for a two-dimensional steady flow of the magnetized Jeffery fluid model over elongated/shrinking sheets, with potential applications such as coating sheets, food products, fiber optics, drilling fluids, and the manufacturing processes of thermoplastic polymers. The model also demonstrates the influence of chemical reaction, magnetic field, and stability analysis which provide a novel contribution to this study. To ensure the ease and effectiveness of this analysis, we transform the set of difference equations governing the system into ordinary equations using the similarity transformation. The reliability of the solution is examined by using stability analysis. The Navier–Stokes equations have been transformed into self-similar equations by adopting appropriate similarity transformations and subsequently solved numerically using the bvp4c (three-stage Labatto-three-A formula) approach. The comparison between the derived asymptotic solutions and previously documented numerical results is quite remarkable. The self-similar equations display a duality of solutions within a limited range of the shrinking parameter, as observed from the data. For each stretching scenario, there is a unique solution. Hence, an examination of temporal stability has been conducted through linear analysis to establish the most fundamentally viable solution. The determination of stability in the analysis is based on the sign of the smallest eigenvalue, which indicates whether a solution is unstable or stable. The analysis of stability reveals that the first solution, which describes the primary flow, remains stable. Through the utilization of graphs, we thoroughly examine and discuss the influence of emerging factors. The numerical results obtained from this analysis demonstrate multiple solutions within a certain range of M 1 ≥ M ci {M}_{1}\ge {M}_{{ci}} , i = 1 , 2 , 3 i=1,2,3 , and no solution in the range M 1 < M ci {M}_{1}\lt {M}_{{ci}} . M ci {M}_{{ci}} denotes the critical values, which increase as the quantities of Sc {\rm{Sc}} increase from 0.3 to 0.9. Similarly, multiple solutions exist for λ ≥ λ ci \lambda \ge {\lambda }_{{ci}} , i = 1 , 2 , 3 i=1,2,3 , and no solution in the range λ < λ ci \lambda \lt {\lambda }_{{ci}} is observed.

Explicit solutions of the generalized Kudryashov’s equation with truncated M-fractional derivative

The main purpose of this article is to study the generalized Kudryashov’s equation with truncated M-fractional derivative, which is commonly used to describe the propagation of wide pulses in nonlinear optical fibers. By employing the complete discriminant system of fourth-order polynomials, various types of explicit solutions are systematically classified, which include periodic solutions, the trigonometric functions, the double-period solutions, and the elliptic function solutions. Additionally, a series of 2D, 3D, and contour plots are generated to visually depict the spatial distribution and evolution of various solutions. This not only advances the development of nonlinear equations in theory but also provides valuable guidance in practical applications.

Type-II Bragg gratings with a 300 nm period fabricated using tightly focused femtosecond pulses and the phase mask technique

1000°C-resistant Bragg gratings (i.e., Type-II Bragg gratings) with a 300 nm period are fabricated in non-photosensitized silica-based optical fibers using tightly focused ultraviolet/visible (400 nm) femtosecond pulses and a phase mask. Five millimeter-long Bragg gratings with a -10 dB transmission dip and -0.1 dB off-resonance insertion loss are demonstrated. Inscription of such gratings is also possible through protective acrylate coatings on the fiber. The Bragg wavelength drift and changes in the transmission of the fiber Bragg gratings are monitored in the course of isothermal annealing performed at 1000°C for 120 hours.

Фотонные кристаллы: оптимизация характеристик и перспективы оптических приложений

Background: Photonic crystals (PCs) have emerged as a new material for light manipulation, providing unprecedented control over light-matter interaction. This unique capacity is due to their periodic dielectric structure, which may produce photonic band gaps that impact photon transmission. Objective: The article summarizes current advances in photonic crystal design and use, focusing on their significance in creating next-generation optical systems. Methods: The article performed a complete literature analysis, concentrating on the most recent PC production and characterization approaches. Innovative techniques like 3D printing, nanoimprint lithography, self-assembly, and advanced computational modelling were studied in depth to optimize their optical characteristics. Results: Recent studies show that PC manufacturing accuracy has increased significantly, allowing for more effective light manipulation and enhanced optical device functioning. Applications such as ultrasensitive sensors, improved optical fibers, and innovative laser designs demonstrate PCs' rising value. Conclusion: The ongoing advancement of photonic crystal technology is laying a solid basis for the next generation of optical devices. These developments improve existing applications and provide opportunities to investigate new functionality in optical and other electromagnetic systems. Incorporating PCs into numerous technical sectors holds the prospect of significant advances in both commercial and scientific fields.

Application of the Optical Fiber Diameter Analyzer for Assessing Cotton Fiber Ribbon Width

ABSTRACT Existing methods for measuring fineness are time-consuming, tedious, and impractical to evaluate many samples. For this reason, the Textile Industry has sought a rapid, accurate, and reliable instrument to determine fiber fineness. Recently, the Optical Fiber Diameter Analyzer (OFDA) was introduced for rapid and precise evaluation of the diameter of different types of fibers. In this study, the OFDA was evaluated for measuring the ribbon width of cotton fiber snippets. One hundred and four carded cotton samples covering a wide range of fiber properties were selected and tested with nine replications per sample. The repeatability of the OFDA diameter measurement was confirmed. Comparisons with the data (cross-sections, AFIS, and Cottonscope) obtained from previous studies on the 104 samples were used to assess the effectiveness of the proposed method. The relationship between ribbon widths measured by Cottonscope and OFDA was found to be weak. Yet, there is a strong correlation between OFDA ribbon width and AFIS standard fineness. We hypothesize that the poor relationship between the Cottonscope and the OFDA is related to the medium in which the measurements are performed. The results are stable and provide measurements closely related to AFIS standard fineness, a trusted measurement within the Textile Industry.

Laser fiber cleave: Modeling and fundamentals

In the laser-assisted fiber cleaving process, an ultrashort, high-energy laser is used to introduce a flaw on the optical fiber surface, and then the fiber is cleaved under a tension or bending load. The quality of the cleaved end depends on the crack propagation from the artificial flaw. To understand the cleaving process and the effects of flaw parameters on cleaving quality, crack propagation is modeled by considering a pre-existing surface flaw using a graph-based finite element method (GraFEA). GraFEA is based on the nonlocal multiple cracking simulation framework for brittle and quasi-brittle materials. First, a three-point bending test is conducted to calibrate material parameters in GraFEA for commercial fused silica glass. Subsequently, the model is validated by four-point bending and ring-on-ring tests. After validation, the fiber cleaving process is investigated by parametric simulations in which different loading types (bending or tension) are considered. Finally, a beneficial process window is obtained and recommended for improved cleaving quality.

Low frequency vibration monitoring of wind turbine tower based on optical fiber sensor and its potential for internet of things

Among all renewable energy sources, wind energy is a cost-effective alternative energy source. The majority of wind turbines are built in harsh environments due to their power generation characteristics, which is one of the prime reasons resulting in frequent failures of wind turbine. Among various failures, the vibration of wind turbine tower cannot be ignored because it is a precursor of the failure of the wind turbine. The electrical vibration sensors have the problems of power supply and electromagnetic interference for the condition assessment of wind turbine tower. A vibration sensor based on optical Fabry-Perot (F-P) interference principle with high sensitivity is designed, fabricated and characterized to further meet the requirements of vibration detection of wind turbine tower. The mechanical simulation model of the diaphragm and optical vibration platform is constructed to verify the sensing characteristic of the F-P optical fiber vibration sensor (OFVS). The experiment results indicate a resonant frequency of the F-P OFVS of 223 Hz, an output sensitivity of 122.22 mV/m·s−2 at 10 Hz, and a horizontal output of less than 6 %. In addition, the designed F-P OFVS possesses the superiorities of compact structure, passive and excellent anti-electromagnetic interference, and has a wide application prospect in the vibration detection of the wind turbine tower.

A disposable fiber-optic plasmonic sensor for chemical sensing

The integration of fiber optics and plasmonic sensors is promising to improve the practical usability over conventional bulky sensors and systems. To achieve high sensitivity, it typically requires fabrication of well-defined plasmonic nanostructures on optical fibers, which greatly increases the cost and complexity of the sensors. Here, we present a fiber-optic sensor system by using chemical absorption of gold nanoparticles and a replaceable configuration. By functioning gold nanoparticles with aptamers or antibodies, we demonstrate the applications in chemical sensing using two different modes. Measuring shift in resonance wavelength enables the Pb2+ detection with a high linearity and a limit of detection of 0.097nM, and measuring absorption peak amplitude enables the detection of E. coli in urinary tract infection with a dynamic range between 103 to 108 CFU/mL. The high sensitivity, simple fabrication and disposability of this sensing approach could pave the way for point-of-care testing with fiber-optic plasmonic sensors.

Amplifying Fibre Optic Sensor Signals with Graphene Oxide-Silver Nanostars

This work presents a straightforward yet impactful method to enhance optical fibre sensor signals by integrating silver nanostars (AgNS) with graphene oxide (GO-AgNS) as a sensing material. AgNS were synthesized successfully via a one-step chemical reduction method using hydroxylamine as a reducing agent. The concentration of hydroxylamine was varied (7.2, 3.6, 1.8, and 0.9) x 10−4 %v/v to optimize AgNS formation, with the longest spike of the nanostar observed at lower hydroxylamine concentrations, as confirmed by transmission electron microscopy (TEM). UV-visible measurements revealed the highest peak absorption for AgNS synthesized using 0.9 x 10−4 %v/v hydroxylamine, 0.05 M sodium hydroxide, 0.8 mM silver nitrate, and 0.045 M sodium citrate, with an average length of 352.62 ± 59.72 nm measured from TEM images. GO was synthesized via a modified Hummer’s method and mixed with AgNS at varying ratios (1:5, 1:10, 1:15, and 1:20) to form GO-AgNS coatings for the fibre optic probe. The GO-AgNS coating at a ratio of 1:5 exhibited the highest light absorption intensity, enhancing optical signal by 218% compared to GO-coated and 174% compared to AgNS-coated fibre optic sensors. These findings demonstrate that embedding AgNS onto the GO matrix structure as a sensing material significantly improves sensor performance, suggesting promising applications for super-sensitive, cost-effective, and rapid detection in fibre optic-based sensors.

Research and correction for over-response phenomenon when using inorganic scintillator optical fiber X-ray sensor to measure off-axis ratio (OAR)

Research and correction for over-response phenomenon when using inorganic scintillator optical fiber X-ray sensor to measure off-axis ratio (OAR)

Long-Term Persistence of Rayleigh Signature of Optical Fibers in Harsh Environment

Long-Term Persistence of Rayleigh Signature of Optical Fibers in Harsh Environment