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Generalized Method to Describe the Propagation of Pulses in Classical and Specialty Optical Fibers
摘要： The comprehension of pulsed light propagation is of paramount importance in fiber optics. Here, we present a general method to describe the propagation of pulses in any kind of optical fiber, regardless of its fabrication process or constituent materials. As a result, we obtain a rich toolbox for the analysis and synthesis of optical fibers, which allows us to circumvent the resolution of Maxwell’s equations by using heavy-computational numerical methods. To illustrate this, we analyze the pulse propagation problem in non-paraxial anisotropic single-core and multi-core fibers that cover a large variety of optical fibers including classical weakly guiding fibers, optical gain fibers, polarization-maintaining fibers, highly nonlinear fibers, and photonic crystal fibers. Moreover, it is shown that our method can be applied to any kind of guided and unguided medium undergoing spatial and temporal perturbations, provided that the distance and temporal width between different consecutive spatial and temporal medium perturbations are respectively higher than the spatial and temporal width of the optical pulses.
关键词： Optical fiber,nonlinear optics,optical pulses
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE International Symposium on Measurements & Networking (M&N) - Catania, Italy (2019.7.8-2019.7.10)] 2019 IEEE International Symposium on Measurements & Networking (M&N) - Water monitoring in smart cities exploiting plastic optical fibers and molecularly imprinted polymers. The case of PFBS detection
摘要： The detection of perfluorobutanesulfonic acid (PFBS) in water is presented for the first time exploiting a low-cost optical chemical sensing strategy, based on plastic optical fibers and molecularly imprinted polymers (MIPs), able to detect pollutants in water. The sensor's response measured in this work for the detection of PFBS is similar to the one obtained with Perfluorooctanesulfonate and investigated. The detection limit of PFBS is considered of interest when compared to those obtained by using different expensive traditional approaches, e.g. high performance liquid chromatography-mass spectrometry (HPLC-MS). Moreover, the use of this sensing approach is a very attractive perspective for fast, in situ, and remote low-cost detection of pollutants in water for smart cities applications.
关键词： molecularly imprinted polymers,pollutants,PFAs,Surface plasmon resonance,plastic optical fibers,optical fiber sensors,water quality,PFBS,Chemical sensors
更新于2025-09-11 14:15:04
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Rigorous Eigenmode Derivations and Spectral Analysis for Step-Index Confocal Parabolic Optical Fibers
摘要： For quite some time, the geometry-dependence of electric fields confined in two-dimensional systems of propagation has been known. We explore a lesser known way in which one can confine light, parabolically. One can use this method to understand the different forms modes take in such fibers and the appropriate eigenfunction for spectral analysis. In this paper, a fiber with a parabolic core and a circular cladding for the preservation of coaxiality are proposed.
关键词： optical fiber,parabolic geometry,optical spectral analysis,geometry,guided waves
更新于2025-09-11 14:15:04
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[IEEE 2019 Systems of Signals Generating and Processing in the Field of on Board Communications - Moscow, Russia (2019.3.20-2019.3.21)] 2019 Systems of Signals Generating and Processing in the Field of on Board Communications - Simulation-Based Prediction of 100-μm-Core Multimode Optical Fiber Bandwidth for 10GBase-LX Systems
摘要： This work is concerned with application of earlier on developed an alternative method for simulation of piecewise regular multimode fiber optic links operating in a few-mode regime for computation of laser-excited optical pulse dynamics during its propagation over irregular silica graded- index multimode optical fibers (MMFs) with extremely large core diameter. Proposed model is based on the piecewise regular representation, and it takes into account launching conditions, differential mode delay, both lower- and higher- order mode chromatic dispersion, differential mode attenuation, mode mixing and power diffusion occurring due to real fiber irregularity and micro- and macro-bends. We present some results of simulation 10GBase-LX optical signal transmission over 100-μm-core MMFs graded-index refractive index profile corresponding to the typical laser-optimized MMFs 50/125 of ISO/IEC Cat. OM2+/OM3 scaled up to 100 μm core.
关键词： higher- order modes,few-mode regime,on-board cable systems,mode coupling,laser-based multi-Gigabit data transmission,large core multimode optical fiber,industrial networks,differential mode delay
更新于2025-09-11 14:15:04
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[IEEE 2019 International Conference on Robots & Intelligent System (ICRIS) - Haikou, China (2019.6.15-2019.6.16)] 2019 International Conference on Robots & Intelligent System (ICRIS) - Research on Security Threats and Protection Strategies of Optical Fiber Communication
摘要： Natural factors, human factors and technical factors have many security threats to optical fiber communication with the improvement of informatization. The security threat of optical fiber communication is analyzed. The integration of military and civilian, the combination of field and fixed, the improvement of the equipment performance, and the establishment of standardized guarantee mechanism and operational procedures need to be strengthened is proposed to improve the protection capability of the optical fiber communication network.
关键词： Security Protection,Optical Fiber Communication,Security Threat
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE 10th International Conference on Mechanical and Aerospace Engineering (ICMAE) - Brussels, Belgium (2019.7.22-2019.7.25)] 2019 IEEE 10th International Conference on Mechanical and Aerospace Engineering (ICMAE) - Optical Fiber Mach-Zehnder Interferometric Strain Sensor Basedon Concatenating Two Micro Cavities Fabricated by A Femtosecond Laser
摘要： An optical fiber Mach-Zehnder interferometer (MZI) is proposed by concatenating two micro cavities that are fabricated by a femtosecond laser. The interferometer is applied for strain sensing with a sensitivity of -664.2 nm/(cid:2)(cid:2) which is comparable to long period fiber grating and taper-based strain sensors. Also, it exhibits a good reversibility in loading and unloading processes. The relationship between intensity variation and applied strain is a quadratic function. The refractive index dependence and temperature dependence of the interferometer are also investigated. Further, this structure is more robust than taper- or trench-based fiber sensors because of no reduction in fiber diameter direction.
关键词： optical fiber Mach-Zehnder interferometric,femtosecond laser,strain sensor
更新于2025-09-11 14:15:04
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Temperature sensitivity investigation of tapered plastic optical fiber-Mach Zehnder interferometer for sensor application
摘要： Mach Zehnder interferometer (MZI) based on plastic optical fiber (POF) is interesting due to its robustness and simple fabrication. In this work, MZI-POF was designed and its sensitivity to temperature change was characterized to investigate its performance for sensor application. The MZI-POF was fabricated by forming two tapers at several distance by simple heat-pull method. The spectra was investigated by launching white light emitting diode (LED) and the output were observed using VIS-NIR spectrometer. It is shown that the wavelength of spectrum peak and spectrum dip were shifted compared to that of un-tapered POF which indicates that the structure serves well as MZI. Sensor sensitivity to temperature was determined by measuring the spectrum for various temperature which was varied from 40oC to 80oC with increment of 5oC. The result showed that the sensor sensitivity is 0.0693nm/oC in terms of peak measurement and 0.0487nm/oC for dip measurement. Therefore, MZI-POF is a potential candidate for temperature sensor.
关键词： Mach Zehnder interferometer,temperature sensitivity,sensor application,plastic optical fiber
更新于2025-09-11 14:15:04
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The Impact of Local Oscillator Frequency Jitter and Laser Linewidth to Ultra High Baud Rate Coherent Systems
摘要： Through theoretical analysis and simulation, we investigate the system impact due to a sinusoidal jitter tone and the resultant local oscillator (LO) laser linewidth requirement in ultra-high baud rate and long distance coherent optical systems. We also carried out experiments in 64Gbaud, dual-polarization (DP)-16QAM systems to verify the theoretical analysis and simulation. We have also obtained a jitter interference tolerance mask to qualify LO lasers. A jitter tone with a frequency lower than ~1MHz has a higher tolerance since it generally causes constant frequency or phase shift, which can be tracked by a receiver DSP. For a jitter tone with a frequency higher than ~1MHz, the tolerance becomes much tighter since the tone will affect laser lineshape and induce equalizer-enhanced phase noise (EEPN). Consequently, a jitter tone in the higher frequency region could severely affect the system performance. Theoretical analysis and numerical result illustrate that EVM2 due to the effect of laser linewidth and a sinusoidal jitter tone is proportional to the weighted sum of [Δν × Bs × L] and [Δfpp×Bs × L]2, where Δν is the laser linewidth, Bs is the baud rate, Δfpp is the laser peak-to-peak frequency deviation due to a sinusoidal jitter tone, and L is the fiber transmission length. This result is applicable for all orders of QAM constellations. The implication to future 100 Gbaud and beyond systems is delineated.
关键词： laser noise,Optical fiber communication,coherent communication
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Random Mode Coupling Assists Kerr Beam Self-Cleaning in a Graded-Index Multimode Optical Fiber
摘要： Spatiotemporal light beam dynamics in multimode ?bers (MMF) recently has attracted renewed interest in both fundamental physics and various ?elds of practical application [1,2]. Recent experiments [2,3] have shown that, owing to the Kerr effect, a process of beam self-cleaning can be observed in graded-index (GRIN) MMFs. As a result, one observes a robust nonlinear beam, which has a size that is close to the fundamental mode at the ?ber output, in contrast to a speckled output beam, which is obtained in the case of the linear regime. In this paper, we numerically investigate the process of beam self-cleaning in GRIN MMFs. Unlike previous approaches [3], where the nonlinear propagation of a spatial beam along the multimode ?ber was described by the generalized 3D nonlinear Schrdinger equation, we use the coupled-mode model, which has the following form: 2i dAp,m dζ = D(n + 1)2Ap,m + p ∑ m+m1=m2+m3 ∑ p+p1=p2+p3 f m,m1,m2,m3 p,p1,p2,p3 Ap1,m1Ap2,m2Ap3,m3 + ∑ m1,p1 Cm,m1 p,p1 Ap1,m1 . These equations separately describe the evolution of the amplitude of each mode Ap,m. The coupled mode approach signi?cantly reduces the computation time, due to the use of a large integration step. To account for the various imperfections of the multimode ?ber, caused by fabrication, bending or tilting, we added a random linear coupling term to the equation. Fig. 1 Dynamics of energy distribution by modes and the output ?eld for the model without random linear coupling (a) and with random linear coupling between degenerate modes (b). In this contribution, we describe various models of random linear coupling between spatial modes, including coupling between all modes, or only between degenerate ones, and investigate the effects of random mode coupling on the beam self-cleaning process. Fig. 1a shows the spatial dynamics of energy distribution among the modes, corresponding to a model without any random linear coupling. In this case, in spite of being in a strong nonlinear regime, the power of the fundamental mode oscillates along the ?ber, and we still obtain a speckled beam at the ?ber output. On the other hand, if we consider a model with random linear coupling between spatial modes with equal mode numbers, one readily observes the appearance of a self-cleaning effect, and the fundamental mode power swiftly stabilizes upon the propagation (see Fig. 1b). The output beam in this case has a size that is close to that of the fundamental mode. The results of numerical investigations are in complete agreement with our experimental data.
关键词： Kerr effect,graded-index multimode optical fiber,beam self-cleaning,random mode coupling
更新于2025-09-11 14:15:04
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Long-Sensing-Length Strain Sensor Based on Optical Fiber Fabry-Perot Interferometer with HCF-SMF Structure
摘要： We proposed and demonstrated an optical fiber Fabry-Perot (F-P) sensor with long sensing length for strain measurement. The structure of the sensor was fabricated with a simple process by splicing a long single mode fiber (SMF) with a short section of hollow-core fiber (HCF). The end of the SMF was cleaved with smooth reflective surface which hence allows the sensing length of the proposed sensor can achieve several centimeters with good visibility. Sensors with different sensing lengths were fabricated and experimentally analyzed in this paper. The relationship between the optical path difference (OPD) of the sensor and strain is found to be linear. With the sensing length of ~10mm and ~49 mm, the sensor can achieve the OPD strain sensitivity of 20.42 nm/ and 115.57 nm/ respectively. Besides, with the sensing length of ~10mm, the OPD temperature sensitivity of the sensor was 187.64 nm/°C. With the advantages of easy making, low cost and long sensing length, it is anticipated that the proposed sensor has great potential in measuring the strain with a large distribution.
关键词： strain measurement,optical fiber sensor,Fabry-Perot interferometer
更新于2025-09-11 14:15:04