Pub Date : 2024-11-07DOI: 10.1016/j.yofte.2024.104026
Régis Donald Hontinfinde , Marc Amour Ayela , Gaston Edah
In this paper, two new solution-type solutions have been presented for the Hirota equation used to describe the propagation of an ultrashort optical pulse in the context of long-distance optical fiber communications. The evolution of these pulses is calculated by means of the Anderson variational method coupled with the Runge–Kutta method of order 4 (RK4) using super-Gaussian and cosh-Gaussian pulses as test functions. The results obtained in this work show that the two solutions presented propagate without distortions and are temporally stable and can be used to overcome the effects of signal distortion in the context of very high data rate transmissions optical communications over homogeneous fiber. The results obtained also show that the central position of the pulse does not affect the dynamics of the different parameters and that only the soliton power and the linear momentum are conserved quantities. Moreover, it should be noted that that the choice between super-Gaussian and chirped cosh-Gaussian profiles has no obvious difference on the propagation dynamics of an ultrashort solitonic pulse in the context of long-haul optical fiber communications. The results of the current paper have not been widely reported before.
{"title":"Dynamics of optical soliton solutions parameters for Hirota equation by variational principle","authors":"Régis Donald Hontinfinde , Marc Amour Ayela , Gaston Edah","doi":"10.1016/j.yofte.2024.104026","DOIUrl":"10.1016/j.yofte.2024.104026","url":null,"abstract":"<div><div>In this paper, two new solution-type solutions have been presented for the Hirota equation used to describe the propagation of an ultrashort optical pulse in the context of long-distance optical fiber communications. The evolution of these pulses is calculated by means of the Anderson variational method coupled with the Runge–Kutta method of order 4 (RK4) using super-Gaussian and cosh-Gaussian pulses as test functions. The results obtained in this work show that the two solutions presented propagate without distortions and are temporally stable and can be used to overcome the effects of signal distortion in the context of very high data rate transmissions optical communications over homogeneous fiber. The results obtained also show that the central position of the pulse does not affect the dynamics of the different parameters and that only the soliton power and the linear momentum are conserved quantities. Moreover, it should be noted that that the choice between super-Gaussian and chirped cosh-Gaussian profiles has no obvious difference on the propagation dynamics of an ultrashort solitonic pulse in the context of long-haul optical fiber communications. The results of the current paper have not been widely reported before.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104026"},"PeriodicalIF":2.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.yofte.2024.104032
Isaack Kamanga , Guo Zhu , Zhi Wang , Fei Liu , Xian Zhou
In the realm of vibration event classification, using the Phi-Optical Time-Domain Reflectometer (Φ-OTDR) and deep learning techniques like Convolutional Neural Networks (CNNs) requires a substantial amount of training data, which can be expensive to collect and annotate. Yet, maximizing the utility of data features from a limited set of samples could enhance training efficacy and classification precision. This study introduces an innovative approach that utilizes a combination of Mel-Frequency Cepstral Coefficients (MFCC) and Differential Phase (DP) features, referred to as MFCC-DP. The MFCCs are extracted from the Rayleigh Backscattered (RBS) signal intensities, while DP features are extracted from the analytic signals of RBS. The MFCC-DP features are used to train a CNN model for event classification. Experimental findings demonstrate a noteworthy enhancement in accuracy, reaching 98.2% with MFCC-DP compared to 92.1% and 94% when using DP and MFCCs, respectively. Furthermore, the results indicate that the use of MFCC-DP reduces the number of events that are difficult to classify due to overlapping features.
{"title":"Enhancing Φ-OTDR vibration event classification by stacking MFCCs and differential phase features using CNNs","authors":"Isaack Kamanga , Guo Zhu , Zhi Wang , Fei Liu , Xian Zhou","doi":"10.1016/j.yofte.2024.104032","DOIUrl":"10.1016/j.yofte.2024.104032","url":null,"abstract":"<div><div>In the realm of vibration event classification, using the Phi-Optical Time-Domain Reflectometer (Φ-OTDR) and deep learning techniques like Convolutional Neural Networks (CNNs) requires a substantial amount of training data, which can be expensive to collect and annotate. Yet, maximizing the utility of data features from a limited set of samples could enhance training efficacy and classification precision. This study introduces an innovative approach that utilizes a combination of Mel-Frequency Cepstral Coefficients (MFCC) and Differential Phase (DP) features, referred to as MFCC-DP. The MFCCs are extracted from the Rayleigh Backscattered (RBS) signal intensities, while DP features are extracted from the analytic signals of RBS. The MFCC-DP features are used to train a CNN model for event classification. Experimental findings demonstrate a noteworthy enhancement in accuracy, reaching 98.2% with MFCC-DP compared to 92.1% and 94% when using DP and MFCCs, respectively. Furthermore, the results indicate that the use of MFCC-DP reduces the number of events that are difficult to classify due to overlapping features.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104032"},"PeriodicalIF":2.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.yofte.2024.104035
Andrei A. Stolov, Jie Li, Adam S. Hokansson
Migration of hydrogen in optical fibers and its chemical reactions with the glass fiber core create added optical loss, that may deteriorate the light transmission through the fiber. Although this subject has been extensively studied and a few theoretical and empirical models linking the attenuation to hydrogen pressure, temperature and time were proposed, none of the models was verified in a broad range of experimental conditions. In this work we investigate a single mode germanium doped fiber that was exposed to 25–––100 psi H2 pressures at temperatures in the range 150 – 250 °C and the exposure times up to 28 days. Different aging protocols were applied to the fiber, and the focus was given to O–H peak development. An empirical approach and a theoretical model, that assumes Gaussian distribution of the activation energies were applied to fit the experimental results. From the theoretical model, it was found that the concentration of precursor available for reaction with hydrogen is orders of magnitude higher than that of non-bridging oxygen hole centers, and that at the applied temperatures the reacted sites belong to the lower-energy wing of the Gaussian distribution. It was also found that parameters of the theoretical model cannot be accurately determined via fitting even a large array of experimental data. In contrast, parameters of the empirical model are easily obtainable from the experiment which makes this approach more practical in hydrogen-related lifetime predictions.
{"title":"Hydrogen-induced O–H peak growth in Ge-doped optical fibers: Verification of empirical and theoretical models","authors":"Andrei A. Stolov, Jie Li, Adam S. Hokansson","doi":"10.1016/j.yofte.2024.104035","DOIUrl":"10.1016/j.yofte.2024.104035","url":null,"abstract":"<div><div>Migration of hydrogen in optical fibers and its chemical reactions with the glass fiber core create added optical loss, that may deteriorate the light transmission through the fiber. Although this subject has been extensively studied and a few theoretical and empirical models linking the attenuation to hydrogen pressure, temperature and time were proposed, none of the models was verified in a broad range of experimental conditions. In this work we investigate a single mode germanium doped fiber that was exposed to 25–––100 psi H<sub>2</sub> pressures at temperatures in the range 150 – 250 °C and the exposure times up to 28 days. Different aging protocols were applied to the fiber, and the focus was given to O–H peak development. An empirical approach and a theoretical model, that assumes Gaussian distribution of the activation energies were applied to fit the experimental results. From the theoretical model, it was found that the concentration of precursor available for reaction with hydrogen is orders of magnitude higher than that of non-bridging oxygen hole centers, and that at the applied temperatures the reacted sites belong to the lower-energy wing of the Gaussian distribution. It was also found that parameters of the theoretical model cannot be accurately determined via fitting even a large array of experimental data. In contrast, parameters of the empirical model are easily obtainable from the experiment which makes this approach more practical in hydrogen-related lifetime predictions.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104035"},"PeriodicalIF":2.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Delta-sigma modulation can achieve single-carrier high-order quadrature amplitude modulation (QAM) or orthogonal frequency division multiplexing (OFDM) transmission with a very high signal-to-noise ratio. We design an encryption structure that combines delta-sigma modulation (DSM) and digital encryption. This not only improves the flexibility of the system, but also masks the spectral characteristics of the DSM signal. Based on this structure, we additionally demonstrate a frequency-time domain masking (FTDM) and digital encryption scheme with improved confidentiality. Frequency domain masking is realized by digital encryption after DSM, and time domain masking is realized by using multi-scroll chaos superposition on the QAM constellation. In addition, the conventional multi-scroll chaos masking scheme runs the risk of being forced to attack by the blind separation algorithm due to the insufficient power of the chaotic signal. The fidelity of DSM to the signal allows the chaotic signal to mask the constellation points with a higher power ratio. Greatly improves the reliability of this method. Finally, a chaotic-based FTDM and digital encryption scheme with a key space of 10207 is implemented in a photonics-aided millimeter radio-over-fiber (ROF) system employing DSM, multi-scroll chaos masking, and deoxyribonucleic acid (DNA) digital encryption. The equivalent 1.67 GBaud encrypted-4096QAM signal is successfully transmitted and decrypted over a 4.6 km wireless link in the DSM-based fiber-wireless integrated system.
{"title":"Frequency-time domain masking and digital encryption system for DSM-based fiber-wireless integrated system","authors":"Tianqi Zheng, Kaihui Wang, Xiongwei Yang, Chengzhen Bian, Weiping Li, Jianjun Yu, Fellow, IEEE","doi":"10.1016/j.yofte.2024.104020","DOIUrl":"10.1016/j.yofte.2024.104020","url":null,"abstract":"<div><div>Delta-sigma modulation can achieve single-carrier high-order quadrature amplitude modulation (QAM) or orthogonal frequency division multiplexing (OFDM) transmission with a very high signal-to-noise ratio. We design an encryption structure that combines delta-sigma modulation (DSM) and digital encryption. This not only improves the flexibility of the system, but also masks the spectral characteristics of the DSM signal. Based on this structure, we additionally demonstrate a frequency-time domain masking (FTDM) and digital encryption scheme with improved confidentiality. Frequency domain masking is realized by digital encryption after DSM, and time domain masking is realized by using multi-scroll chaos superposition on the QAM constellation. In addition, the conventional multi-scroll chaos masking scheme runs the risk of being forced to attack by the blind separation algorithm due to the insufficient power of the chaotic signal. The fidelity of DSM to the signal allows the chaotic signal to mask the constellation points with a higher power ratio. Greatly improves the reliability of this method. Finally, a chaotic-based FTDM and digital encryption scheme with a key space of 10<sup>207</sup> is implemented in a photonics-aided millimeter radio-over-fiber (ROF) system employing DSM, multi-scroll chaos masking, and deoxyribonucleic acid (DNA) digital encryption. The equivalent 1.67 GBaud encrypted-4096QAM signal is successfully transmitted and decrypted over a 4.6 km wireless link in the DSM-based fiber-wireless integrated system.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104020"},"PeriodicalIF":2.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.yofte.2024.104017
Jérémy Saucourt , Benjamin Gobé , David Helbert , Agnès Desfarges-Berthelemot , Vincent Kermene
We investigate a method to retrieve full-complex models (Transmission Matrix and Neural Network) of a highly multimode fiber (140 LP modes/polarization) using a straightforward machine learning approach, without the need of a reference beam. The models are first validated by the high fidelity between the predicted and the experimental images in the near field and far field output planes (Pearson correlation coefficient between 97.5% and 99.1% with our trained Transmission Matrix or Neural Network). Their accuracy was further confirmed by successful 3D beam shaping, a task achievable only with a true full complex model. As a prospect, we also demonstrate the ability of our neural network architecture to model nonlinear Kerr propagation in gradient index multimode fiber and predict the output beam shape.
{"title":"Machine learning-driven complex models for wavefront shaping through multimode fibers","authors":"Jérémy Saucourt , Benjamin Gobé , David Helbert , Agnès Desfarges-Berthelemot , Vincent Kermene","doi":"10.1016/j.yofte.2024.104017","DOIUrl":"10.1016/j.yofte.2024.104017","url":null,"abstract":"<div><div>We investigate a method to retrieve full-complex models (Transmission Matrix and Neural Network) of a highly multimode fiber (140 LP modes/polarization) using a straightforward machine learning approach, without the need of a reference beam. The models are first validated by the high fidelity between the predicted and the experimental images in the near field and far field output planes (Pearson correlation coefficient between 97.5% and 99.1% with our trained Transmission Matrix or Neural Network). Their accuracy was further confirmed by successful 3D beam shaping, a task achievable only with a true full complex model. As a prospect, we also demonstrate the ability of our neural network architecture to model nonlinear Kerr propagation in gradient index multimode fiber and predict the output beam shape.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104017"},"PeriodicalIF":2.6,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Addressing the challenges posed by escalating data demands, connected devices, and bandwidth-hungry technologies, Fiber Wireless (FiWi) networks offer a holistic solution. Nevertheless, among the most significant challenges faced by FiWi networks are the component deployment, its connectivity, and performance under varying loads. In the FiWi network the ONUs plays a pivotal role in collecting and forwarding wireless-generated traffic thereby emphasizing the need for efficient resource management to ensure network reliability. Overloading of ONU often results in network congestion, as ONU serves as an intermediatory node between optical backend and wireless frontend. Thus, traffic offloading is a great solution by identifying underloaded ONUs and redirecting a portion of the excess traffic from overloaded ONUs to underloaded ONUs to maintain balanced resource allocation. However, identification of wireless routers within the wireless frontend is a crucial step, enabling strategic decision-making in rerouting traffic and promoting load balancing. Thus, the proposed work suggests a new hybrid two step method termed as MLGO (Machine learning based Mountain Gazelle Optimization Algorithm) which first uses machine learning based k-means clustering algorithm for nodes (Wireless routers and ONU) placement and connectivity and the second step employs the Mountain Gazelle Optimization algorithm (MGO) and GA for identifying optimum wireless routers for traffic offloading which enhances the overall FiWi network performance. The paper contributes to the evolution of FiWi networks, ensuring optimal connectivity, efficient resource utilization, and enhanced packet delivery ratio for end-users. Simulation results validate the effectiveness of this two-step proposed approach.
光纤无线（FiWi）网络为应对不断升级的数据需求、联网设备和高带宽技术所带来的挑战提供了全面的解决方案。然而，FiWi 网络面临的最大挑战是组件部署、其连接性以及在不同负载下的性能。在 FiWi 网络中，ONU 在收集和转发无线产生的流量方面发挥着关键作用，因此强调了高效资源管理以确保网络可靠性的必要性。ONU 作为光后端和无线前端之间的中间节点，其超载往往会导致网络拥塞。因此，流量卸载是一个很好的解决方案，它可以识别负载不足的 ONU，并将过载 ONU 的部分多余流量转发给负载不足的 ONU，以保持资源分配平衡。然而，识别无线前端内的无线路由器是一个关键步骤，有助于在重新路由流量和促进负载平衡方面做出战略决策。因此，本文提出了一种新的两步混合方法，称为 MLGO（基于机器学习的山地瞪羚优化算法），该方法首先使用基于机器学习的 k-means 聚类算法进行节点（无线路由器和 ONU）的放置和连接，第二步使用山地瞪羚优化算法（MGO）和 GA 来识别最佳无线路由器，以实现流量卸载，从而提高 FiWi 网络的整体性能。本文有助于 FiWi 网络的发展，确保为终端用户提供最佳的连接、高效的资源利用和更高的数据包传输率。仿真结果验证了这一两步建议方法的有效性。
{"title":"MLGO: A machine learning-based mountain gazelle optimization algorithm for efficient resource management and load balancing in fiber wireless access networks","authors":"Mausmi Verma , Uma Rathore Bhatt , Raksha Upadhyay , Vijay Bhat","doi":"10.1016/j.yofte.2024.104014","DOIUrl":"10.1016/j.yofte.2024.104014","url":null,"abstract":"<div><div>Addressing the challenges posed by escalating data demands, connected devices, and bandwidth-hungry technologies, Fiber Wireless (FiWi) networks offer a holistic solution. Nevertheless, among the most significant challenges faced by FiWi networks are the component deployment, its connectivity, and performance under varying loads. In the FiWi network the ONUs plays a pivotal role in collecting and forwarding wireless-generated traffic thereby emphasizing the need for efficient resource management to ensure network reliability. Overloading of ONU often results in network congestion, as ONU serves as an intermediatory node between optical backend and wireless frontend. Thus, traffic offloading is a great solution by identifying underloaded ONUs and redirecting a portion of the excess traffic from overloaded ONUs to underloaded ONUs to maintain balanced resource allocation. However, identification of wireless routers within the wireless frontend is a crucial step, enabling strategic decision-making in rerouting traffic and promoting load balancing. Thus, the proposed work suggests a new hybrid two step method termed as MLGO (Machine learning based Mountain Gazelle Optimization Algorithm) which first uses machine learning based k-means clustering algorithm for nodes (Wireless routers and ONU) placement and connectivity and the second step employs the Mountain Gazelle Optimization algorithm (MGO) and GA for identifying optimum wireless routers for traffic offloading which enhances the overall FiWi network performance. The paper contributes to the evolution of FiWi networks, ensuring optimal connectivity, efficient resource utilization, and enhanced packet delivery ratio for end-users. Simulation results validate the effectiveness of this two-step proposed approach.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104014"},"PeriodicalIF":2.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1016/j.yofte.2024.104027
Xiaolu Cao , Mingming Luo , Jianfei Liu , Jie Ma
Mode coupling, often overlooked at an imperfect Fresnel surface, is now examined in a fluorine-trench dual-mode fiber to avoid energy losses and signal degradation. For invisible defects on the reflecting surface, the orthogonal forward LP01 (LP11) mode with group velocity vgLP01 (vgLP11) partially converts to the backward LP11 (LP01) mode with vgLP11 (vgLP01) through a transfer matrix, respectively. Consequently, this interaction generates a unique hybrid backward mode, which results in an average round-trip time delay and the mean of the velocities, (vgLP01 + vgLP11)/2. Upon harvesting and analyzing the backward reflections using a high-resolution coherent optical frequency domain reflectometry, a Fresnel reflection peak corresponding to the hybrid mode is observed with a high signal-to-noise ratio precisely between the LP01 and LP11 peaks. Additionally, the frequency difference between the hybrid and LP01 (or LP11) modes is calculated to be 20.625 Hz exactly half of the 41.250 Hz difference between the LP01 and LP11 modes. Further testing on five additional fiber segments ranging from 8.812 m to 10.812 m corroborates this theory, as their vghybrid values align closely with (vgLP01 + vgLP11)/2. Our analytical insights detail the dynamic mode coupling at an imperfect Fresnel surface, promising a flexible method for dynamic mode observation and regulation for mode division multiplexing optical fiber communications, particularly in enhancing the detection and mitigation of defects at fiber lasing end faces.
{"title":"Mode coupling at an imperfect Fresnel surface in a fluorine-trench dual-mode fiber","authors":"Xiaolu Cao , Mingming Luo , Jianfei Liu , Jie Ma","doi":"10.1016/j.yofte.2024.104027","DOIUrl":"10.1016/j.yofte.2024.104027","url":null,"abstract":"<div><div>Mode coupling, often overlooked at an imperfect Fresnel surface, is now examined in a fluorine-trench dual-mode fiber to avoid energy losses and signal degradation. For invisible defects on the reflecting surface, the orthogonal forward LP<sub>01</sub> (LP<sub>11</sub>) mode with group velocity <em>v</em><sub>g</sub><sup>LP<sub>01</sub></sup> (<em>v</em><sub>g</sub><sup>LP<sub>11</sub></sup>) partially converts to the backward LP<sub>11</sub> (LP<sub>01</sub>) mode with <em>v</em><sub>g</sub><sup>LP<sub>11</sub></sup> (<em>v</em><sub>g</sub><sup>LP<sub>01</sub></sup>) through a transfer matrix, respectively. Consequently, this interaction generates a unique hybrid backward mode, which results in an average round-trip time delay and the mean of the velocities, (<em>v</em><sub>g</sub><sup>LP<sub>01</sub></sup> + <em>v</em><sub>g</sub><sup>LP<sub>11</sub></sup>)/2. Upon harvesting and analyzing the backward reflections using a high-resolution coherent optical frequency domain reflectometry, a Fresnel reflection peak corresponding to the hybrid mode is observed with a high signal-to-noise ratio precisely between the LP<sub>01</sub> and LP<sub>11</sub> peaks. Additionally, the frequency difference between the hybrid and LP<sub>01</sub> (or LP<sub>11</sub>) modes is calculated to be 20.625 Hz exactly half of the 41.250 Hz difference between the LP<sub>01</sub> and LP<sub>11</sub> modes. Further testing on five additional fiber segments ranging from 8.812 m to 10.812 m corroborates this theory, as their <em>v</em><sub>g</sub><sup>hybrid</sup> values align closely with (<em>v</em><sub>g</sub><sup>LP<sub>01</sub></sup> + <em>v</em><sub>g</sub><sup>LP<sub>11</sub></sup>)/2. Our analytical insights detail the dynamic mode coupling at an imperfect Fresnel surface, promising a flexible method for dynamic mode observation and regulation for mode division multiplexing optical fiber communications, particularly in enhancing the detection and mitigation of defects at fiber lasing end faces.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104027"},"PeriodicalIF":2.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper demonstrates the use of the multi-objective grey wolf algorithm to optimize a discrete Raman amplifier (DRA) in a P2O5-doped optical fiber. Specifically, the multi-objective grey wolf algorithm is combined with the DRA to carry out a process that seeks to maximize the gain and minimize the ripple. The P2O5-doped optical fiber employed in this study has a Raman gain coefficient spectrum with multiple peaks with different frequency shifts. This allows them to be combined in more complex ways than optical fibers with a single peak in the Raman gain spectrum. Consequently, the gain curve produced with this fiber has the potential to be more adjustable even when fewer pumps are used. Thus, this paper explores this fact to perform, to the best of our knowledge, the first specialized optimization process reported in the scientific literature of a wideband discrete Raman amplifier in a P2O5-doped optical fiber. With a different gain profile of this fiber compared to those of traditional standard optical fibers, it was possible to design a wideband DRA, going from 1530 nm to 1675 nm, covering C+L+U bands, maintaining a ripple of up to 8 dB with a net gain of 14 dB using only 3 pumps. Moreover, this work demonstrates for the first time, through a comparative analysis, that the multi-objective grey wolf algorithm performs better than the standard and well-known non-dominated sorting genetic optimization algorithm to optimize a DRA in a P2O5-doped optical fiber. The proposed DRA is a feasible, low-cost, and simple alternative for building fiber amplifiers for future high-bandwidth and wideband wavelength division multiplexing (WDM) communication systems, network infrastructures such as data centers, undersea cables, 5G and beyond, and cutting-edge research applications.
{"title":"Optimization of a wideband discrete Raman amplifier in a P2O5-doped optical fiber using multi-objective grey wolf algorithm","authors":"Luís C.B. Silva, Helder R.O. Rocha, Marcelo E.V. Segatto, Carlos E.S. Castellani","doi":"10.1016/j.yofte.2024.104023","DOIUrl":"10.1016/j.yofte.2024.104023","url":null,"abstract":"<div><div>This paper demonstrates the use of the multi-objective grey wolf algorithm to optimize a discrete Raman amplifier (DRA) in a P<sub>2</sub>O<sub>5</sub>-doped optical fiber. Specifically, the multi-objective grey wolf algorithm is combined with the DRA to carry out a process that seeks to maximize the gain and minimize the ripple. The P<sub>2</sub>O<sub>5</sub>-doped optical fiber employed in this study has a Raman gain coefficient spectrum with multiple peaks with different frequency shifts. This allows them to be combined in more complex ways than optical fibers with a single peak in the Raman gain spectrum. Consequently, the gain curve produced with this fiber has the potential to be more adjustable even when fewer pumps are used. Thus, this paper explores this fact to perform, to the best of our knowledge, the first specialized optimization process reported in the scientific literature of a wideband discrete Raman amplifier in a P<sub>2</sub>O<sub>5</sub>-doped optical fiber. With a different gain profile of this fiber compared to those of traditional standard optical fibers, it was possible to design a wideband DRA, going from 1530 nm to 1675 nm, covering C+L+U bands, maintaining a ripple of up to 8 dB with a net gain of 14 dB using only 3 pumps. Moreover, this work demonstrates for the first time, through a comparative analysis, that the multi-objective grey wolf algorithm performs better than the standard and well-known non-dominated sorting genetic optimization algorithm to optimize a DRA in a P<sub>2</sub>O<sub>5</sub>-doped optical fiber. The proposed DRA is a feasible, low-cost, and simple alternative for building fiber amplifiers for future high-bandwidth and wideband wavelength division multiplexing (WDM) communication systems, network infrastructures such as data centers, undersea cables, 5G and beyond, and cutting-edge research applications.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104023"},"PeriodicalIF":2.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-03DOI: 10.1016/j.yofte.2024.104033
Vaclav Prajzler, Marek Zikmund
We report on the properties of the Power over Fiber (PoF) system using a High-Power Laser Source (HPLS) operating at 1470 nm with an optical power of up to 2.0 W. Graded-index and step-index optical fibers with a core diameter of 50 µm were used for transmission and two types of Photovoltaic Power Converters (PPCs) were used for optical power to electricity conversion. We experimentally demonstrated the powering to a distance of 5855 m, where we achieved the electric power of 44.4 mW and estimated the possibility of powering to distances longer than 9000 m with the input optical power of 15 W, where we expect to achieve the delivery of the electric power around 150 mW.
{"title":"Power over fiber system using high-power laser source operating at 1470 nm with maximum power 2.0 W for powering to distance up to 5855 m","authors":"Vaclav Prajzler, Marek Zikmund","doi":"10.1016/j.yofte.2024.104033","DOIUrl":"10.1016/j.yofte.2024.104033","url":null,"abstract":"<div><div>We report on the properties of the Power over Fiber (PoF) system using a High-Power Laser Source (HPLS) operating at 1470 nm with an optical power of up to 2.0 W. Graded-index and step-index optical fibers with a core diameter of 50 µm were used for transmission and two types of Photovoltaic Power Converters (PPCs) were used for optical power to electricity conversion. We experimentally demonstrated the powering to a distance of 5855 m, where we achieved the electric power of 44.4 mW and estimated the possibility of powering to distances longer than 9000 m with the input optical power of 15 W, where we expect to achieve the delivery of the electric power around 150 mW.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104033"},"PeriodicalIF":2.6,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.yofte.2024.104028
Alexander Sudin , Igor Volkov , Sergey Ushakov , Konstantin Nishchev , Dmitry Korobko , Andrei Fotiadi
We present an experimental study of a long Er/Yb-doped fiber ring laser with a low fundamental frequency of 0.678 MHz. By solely adjusting the quarter-wave plate in the polarization controller, we uncovered a series of reproducible laser generation regimes. Among these, multiple soliton bunches were harmonically mode-locked to low-order cavity harmonics (from the 3rd to the 8th). Notably, we also identified a regime featuring a stable soliton train harmonically mode-locked to the 472nd cavity harmonic at 320 MHz. This regime demonstrated exceptional harmonic mode-locking stability, with a supermode suppression level of 49 dB corresponding to the timing jitter on the order of a few picoseconds. We attribute this remarkable stability to an exact optoacoustic resonance between the laser repetition rate and the fiber eigen acoustic mode frequencies, specifically identified as R06 and TR2,15. These findings represent a significant advancement in high-performance fiber laser operation, particularly in enhancing the stability of lasers with sub-MHz fundamental frequencies capable to generate regular pulses with much higher repetition rates.
{"title":"Enhancing high-order harmonic mode-locking in Er/Yb-Doped fiber lasers with sub-MHz fundamental frequency via optoacoustic resonance","authors":"Alexander Sudin , Igor Volkov , Sergey Ushakov , Konstantin Nishchev , Dmitry Korobko , Andrei Fotiadi","doi":"10.1016/j.yofte.2024.104028","DOIUrl":"10.1016/j.yofte.2024.104028","url":null,"abstract":"<div><div>We present an experimental study of a long Er/Yb-doped fiber ring laser with a low fundamental frequency of 0.678 MHz. By solely adjusting the quarter-wave plate in the polarization controller, we uncovered a series of reproducible laser generation regimes. Among these, multiple soliton bunches were harmonically mode-locked to low-order cavity harmonics (from the 3rd to the 8th). Notably, we also identified a regime featuring a stable soliton train harmonically mode-locked to the 472nd cavity harmonic at 320 MHz. This regime demonstrated exceptional harmonic mode-locking stability, with a supermode suppression level of 49 dB corresponding to the timing jitter on the order of a few picoseconds. We attribute this remarkable stability to an exact optoacoustic resonance between the laser repetition rate and the fiber eigen acoustic mode frequencies, specifically identified as R<sub>06</sub> and TR<sub>2</sub>,<sub>15</sub>. These findings represent a significant advancement in high-performance fiber laser operation, particularly in enhancing the stability of lasers with sub-MHz fundamental frequencies capable to generate regular pulses with much higher repetition rates.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"88 ","pages":"Article 104028"},"PeriodicalIF":2.6,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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