Journal of Optical Communications and Networking最新文献

{"title":"Experimental coexistence of quantum key distribution and high-power classical communication over 101.6 km hollow-core fiber","authors":"Weiwen Kong;Tianqi Dou;Lei Zhang;Peng Li;Zhenhua Li;Lipeng Feng;Nan Lu;Xuewei Kan;Yongmei Sun;Jianjun Tang;Shibiao Tang","doi":"10.1364/JOCN.567260","DOIUrl":"https://doi.org/10.1364/JOCN.567260","url":null,"abstract":"The integration of quantum key distribution (QKD) with classical optical networks has emerged as a pivotal strategy for building secure communication infrastructures. However, achieving their coexistence in silica-core fibers faces inherent limitations due to nonlinear interference, particularly under high classical signal power. In this paper, we experimentally demonstrate the coexistence of classical optical transport networks and QKD over 101.6 km of hollow-core fiber (HCF) with classical power exceeding 20 dBm for the first time to the best of our knowledge. Through systematic theoretical analysis, we characterize HCF’s transmission loss and nonlinear noise generation mechanisms, revealing its unique compatibility with high-power classical–quantum coexistence compared to conventional fibers. To address spectral interference from HCF’s absorption peaks and nonlinear effects, we propose a spectrally optimized multi-stage allocation (SOMA) scheme that coordinates low-loss channel selection and noise suppression. Experimental validation shows that, under the SOMA scheme, coexisting classical signals achieve 19 dBm in single-wavelength configuration and 21 dBm in multi-wavelength configuration, while maintaining a secure key rate above 10 kbps. This breakthrough establishes HCF as a viable platform for simultaneous high-capacity classical communication and quantum-secured data transmission, overcoming critical power limitations of existing fiber-based coexistence systems.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 10","pages":"914-924"},"PeriodicalIF":4.3,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technology convergence is reshaping the 6G access network architecture, but are our infrastructures ready to cope? [Invited]","authors":"Alexandros Stavdas;Evangelos Kosmatos;Marco Quagliotti;Mauro Agus;Albert Rafel;Christos Matrakidis;Ian Cooper","doi":"10.1364/JOCN.566480","DOIUrl":"https://doi.org/10.1364/JOCN.566480","url":null,"abstract":"The goal of 6G is to further advance the quality of experience in human–human communications while it transforms the I4.0 landscape by integrating a diverse set of technologies, services, and applications. To achieve this goal, there are rapid convergence steps between wireline and wireless technologies toward a unified transportation platform, something that prompts architectural modifications. Intelligence is now distributed closer to end-users, with far-edge nodes becoming essential. However, these nodes must balance performance and affordability for operators. Moreover, the converged wireline and wireless technologies must consider the scarcity of fiber in the last mile. In this work, we contribute to the debate of parallel, decoupled fiber infrastructures versus a single passive PtMP connectivity scheme under the framework of fiber scarcity and for residential users with multi-Gb/s line rates, while small cells exploit mmWave technology with <tex>${gt}{100};{rm MHz}$</tex> RF bandwidth. Our analysis is based on the information supplied by operators regarding the practical constraints and limitations arising from real-life deployments, and it is based on realistic geospatial data. We conclude that fiber utilization becomes prohibitively high under both alternatives when low-cost, gray interfaces are employed, and the deployments become viable in terms of fiber utilization only when colored interfaces and WDM are introduced. Furthermore, this work contributes to the discussion on the efficacy of next-generation PON technology in accommodating varied capacity requirements without increasing fiber use. The recently announced 25G and 50G TDM PONs are struggling to satisfy connectivity demands within the current fiber deployment frameworks when small cells utilizing high-layer splits (F1) and residential users are served by multi-Gb/s line rates. Beyond this point, when small cells employing low-layer splits are deployed alongside multi-Gb/s line-rate residential users, a shared scheme utilizing PtMP trees and technologies supporting a total capacity of 400G seems to be the next barrier to reach to prevent the depletion of fiber infrastructures. At the end, we report our findings based on the benchmark of alternative 400G solutions against their resource utilization.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 11","pages":"E94-E108"},"PeriodicalIF":4.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OpenNOP: an open-source network observability platform enabling multi-vendor multi-layer monitoring and ML analysis","authors":"Nathan Ellsworth;Sebastian Troia;Omran Ayoub;Tianliang Zhang;Andrea Fumagalli","doi":"10.1364/JOCN.560632","DOIUrl":"https://doi.org/10.1364/JOCN.560632","url":null,"abstract":"Network operators rely on the fault, configuration, accounting, performance, and security (FCAPS) model for efficient network management using traditional monitoring solutions that are often costly and proprietary. This paper introduces OpenNOP, an open-source, multi-layer, and multi-vendor network observability platform designed for fault detection, configuration tracking, and performance monitoring. OpenNOP collects and processes network metrics in a time-series database, enabling real-time visualization and AI-driven predictive analytics. Deployed in a multi-vendor optical transport testbed, it facilitates ML-based inference of network disturbances. OpenNOP uses scripted automation to control the generation of network disturbances and the collection of L1/L2/L3 metrics and then train and test ML models to infer the noise profile based on those metrics. By providing a scalable and extensible alternative to proprietary tools, OpenNOP advances network monitoring, predictive maintenance, and AI explainability.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 10","pages":"D167-D179"},"PeriodicalIF":4.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forthcoming optical x-haul infrastructure supporting 6G mobile network requirements","authors":"C. Papapavlou;K. Moschopoulos;C. Christofidis;D. Uzunidis;K. Paximadis;D. M. Marom;R. Munoz;M. Nazarathy;I. Tomkos","doi":"10.1364/JOCN.571798","DOIUrl":"https://doi.org/10.1364/JOCN.571798","url":null,"abstract":"The sixth generation of communication networks necessitates a series of significant technological innovations to accommodate ultra-high rates, ultra-low latency, high energy efficiency, and software-defined programmability for supporting the emerging use cases and the exponential growth in traffic demands. Ultra-wideband (UWB) and spatial division multiplexing technologies have emerged as key enablers in meeting these challenges, offering both scalable network capacity and improved energy efficiency. In this paper, we propose an advanced optical transport architecture designed to fulfill the rigorous performance criteria of next-generation optical networks covering all critical network segments. At the core of this infrastructure—the backhaul segment—we introduce a three-layered UWB/SDM-based multi-granular optical node architecture that utilizes photonic integrated circuit (PIC)-based waveband selective switches, enabling scalable network performance and delivering over 10 Pb/s of flexible optical switching capacity while maintaining a high optical signal-to-noise and interference ratio. At the network edge—the fronthaul segment—we introduce a spatially diverse point-to-multipoint PIC-based optical subcarrier interconnectivity architecture that incorporates a low-loss module—referred to as the interlacer—which interconnects cascaded half-band Nyquist-shaped interleaver filters in order to flexibly perform routing at the subcarrier group level. Across all network segments, we consider innovative, energy-efficient optical digital-to-analog converter-based transceivers capable of achieving transmission rates in the order of terabits per second per channel, while ensuring a small footprint and low power consumption. These transceivers can be flexibly reconfigured to either direct detect or coherent operation, serving the specific needs of the different network segments. Extensive numerical simulations are conducted, with parameters mostly derived from experimental data, to assess the feasibility, scalability, and cascadability of the subsystems that are incorporated to optimize the overall performance of the proposed architecture. Finally, the overall design ensures full compatibility with a service management and orchestration framework, enabling software-defined programmability across all interconnected segments.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 11","pages":"E82-E93"},"PeriodicalIF":4.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the feasibility of analog fiber dispersion-based photonic beamforming for mmWave wireless access over 100  GHz DWDM grids","authors":"Zoran Vujicic;Xavier Gelabert;Maria C. Santos;Rodrigo Mendez;Roberto Gaudino","doi":"10.1364/JOCN.567208","DOIUrl":"https://doi.org/10.1364/JOCN.567208","url":null,"abstract":"We investigate the spectral coexistence feasibility of analog optically driven mmWave antenna beamforming over dispersive fiber links within standardized dense wavelength-division multiplexing (DWDM) grids, targeting next-generation wireless mobile network broadband use cases. Our analysis focuses on integration with legacy passive optical network (PON) infrastructure, using three representative deployment scenarios to evaluate compatibility under practical spectral constraints. We present a use case-driven spectral feasibility assessment of analog radio-over-fiber (ARoF)-based mmWave beam steering over DWDM grids, using a numerical framework that evaluates beamwidth requirements under link distance, carrier frequency, as well as fiber and component spectral constraints. We demonstrate that ARoF carrier frequency optimization, governed by WDM grid and component spectral tolerances, enables optimized beam steering resolution.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 11","pages":"E70-E81"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proactive congestion control for fast switchover and optical path at mobile midhaul utilizing optimized parallel traffic prediction with multi-thread and multi-processing procedures","authors":"Yuka Okamoto;Hirotaka Ujikawa;Kenji Miyamoto;Tatsuya Shimada;Tomoaki Yoshida","doi":"10.1364/JOCN.563719","DOIUrl":"https://doi.org/10.1364/JOCN.563719","url":null,"abstract":"According to the 3rd Generation Partnership Project, it is necessary to keep end-to-end latency to less than 5 ms in 5G mobile networks to achieve remote applications that replace on-site work and operations. The challenge here is that the bursty traffic (e.g., video) abruptly changes on a short timescale. Bursty traffic has an instantaneous high bitrate, which can exceed the link rate of the mobile midhaul (MMH) and thereby cause congestion, leading to an increase in latency. We propose a proactive congestion control method that performs parallel prediction of distributed unit (DU) traffic and fast switchover of the central unit (CU) and optical path in the MMH. Since the processing load of traffic analysis increases in accordance with the number of DUs, the CPU used for prediction becomes overloaded when many DUs are aggregated. This leads to concerns that the prediction cannot be completed in advance, that the timing of control is shifted, and that congestion occurs when switching is performed, thereby increasing the latency. The key idea of the proposed method is to optimize the number of CPU cores and threads for parallel prediction of the DU. To evaluate its feasibility and effectiveness, we experimentally optimized the number of CPU cores, thread allocations, and prediction periods and then estimated the maximum number of simultaneous predictions. The experimental results for a simple condition where video traffic and background traffic are mixed show that our prototype controller successfully achieved a latency at the MMH as low as 1 ms with appropriate congestion control. Our findings demonstrate the latency reduction effect of the proposed congestion control method for MMH in an aggregated DU configuration for applications with severe latency requirements such as remote control.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 11","pages":"E60-E69"},"PeriodicalIF":4.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient verification algorithm for topology and quality of optical fibers in optical-circuit-switched data center networks","authors":"Kazuya Anazawa;Takeru Inoue;Toru Mano;Ryotaro Taniguchi;Yoshiaki Sone;Eiji Oki","doi":"10.1364/JOCN.563868","DOIUrl":"https://doi.org/10.1364/JOCN.563868","url":null,"abstract":"The introduction of optical circuit switches (OCSs) has enabled the implementation of capacity- and energy-efficient networks in production data centers. To correctly operate optical-circuit-switched data center networks (OCS DCNs), fibers between pairs of terminals (e.g., servers or top-of-rack switches) and OCSs should be verified before starting operations; otherwise, unexpected failures during operations could occur. However, this task is difficult because OCSs cannot use topology discovery or link-monitoring functions, which are only available on electrical packet switches. We thus studied a fiber-topology and quality verification (FTQV) problem for OCS DCNs. Though a previous study inspected fibers between pairs of OCSs in hierarchical OCS DCNs using only one dedicated tester for fiber probing, making the process time-consuming, we consider verifying fibers between pairs of terminals and OCSs by using the digital diagnostic monitoring (DDM) function at multiple terminals. We thus developed new theories, to the best of our knowledge, for correctly carrying out FTQV even when parallel probes are sent and then designed an algorithm that efficiently solves the FTQV problem with near-optimal inspection steps. We also theoretically analyzed the conditions of detectable and undetectable malfunctioning fibers given the maximum measurement error of the DDM function. Experimental results indicate the correctness of our theoretical analysis and superior performance of our algorithm; it completes FTQV at most 93.0 times faster than a baseline algorithm. The feasibility of our algorithm was also demonstrated through evaluations on an actual network.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 10","pages":"900-913"},"PeriodicalIF":4.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time burst-mode digital signal processing for passive optical networks","authors":"Ji Zhou;Kainan Wu;Haide Wang;Jinyang Yang;Weiping Liu;Junwen Zhang;Changyuan Yu;Xiangjun Xin;Liangchuan Li","doi":"10.1364/JOCN.560191","DOIUrl":"https://doi.org/10.1364/JOCN.560191","url":null,"abstract":"Driven by ever-increasing capacity demands, the 50G passive optical network (PON) is maturing gradually. One of the main challenges for the 50G PON is implementing burst-mode digital signal processing (BM-DSP) for the burst upstream signal. This paper demonstrates a real-time BM-DSP for burst reception of a 25 Gbit/s on-off keying signal to meet the asymmetric-mode 50G PON demand. The real-time BM-DSP includes BM frequency-domain timing recovery and a BM frequency-domain equalizer, which can be fast converged based on the <tex>${sim}42;text{ns}$</tex> designed preamble. Meanwhile, the simplified implementations for fast Fourier transform, minimum mean square error, and decision-directed least-mean-square-error algorithms decrease the DSP resources by 28.57% compared to the conventional implementation without optimization, enabling the loading of real-time BM-DSP in a field programmable gate array with limited DSP resources. The real-time implementation of BM-DSP can guide the design of application-specific integrated circuits for 50G PON.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 10","pages":"891-899"},"PeriodicalIF":4.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disaggregated and transparent multi-band optical continuum across access, horseshoe aggregation, and metro IPoWDM networks","authors":"Roberto Morro;Emilio Riccardi;Anna Chiado' Piat;Annachiara Pagano;Evangelos Kosmatos;Alexandros Stavdas;Chris Matrakidis;Shiyi Xia;Henrique Freire Santana;Nicola Calabretta;Pol Gonzalez;Luis Velasco;Andrea Sgambelluri;Jordi Ortiz;Enrique Fernandez;Pablo Pavon-Marino;Ramon Casellas;Oscar Gonzales De Dios;Filippo Cugini;Alessio Giorgetti","doi":"10.1364/JOCN.569327","DOIUrl":"https://doi.org/10.1364/JOCN.569327","url":null,"abstract":"The limitations of segmented and power-inefficient legacy optical networks underscore the need for a disaggregated, transparent multi-band optical continuum spanning access, aggregation, and metro domains. In this work, we demonstrate the first field trial, to our knowledge, of a disaggregated and transparent multi-band optical network interconnecting access, aggregation, and metro segments over both the C- and O-bands. The proposed architecture extends the optical continuum from antenna sites through O-band access links to aggregation hubs, and further into a C-band metro-core network, eliminating intermediate opto-electronic conversions. The data plane integrates SOA-based O-band switching for dynamic signal routing and loss compensation, while the control plane is realized through an innovative hierarchical SDN-based solution. This control plane orchestrates end-to-end transparent paths across multiple domains, spectral bands, and layers, leveraging standardized protocols and models for interoperability. Experimental validation shows the seamless multi-band interconnection, demonstrating effective multi-domain orchestration, optical transparency, and control scalability.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 10","pages":"C170-C181"},"PeriodicalIF":4.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simplified coherent TDM-PON in upstream burst-mode detection with enhanced DC leakage tolerance","authors":"An Yan;Renle Zheng;Penghao Luo;Yongzhu Hu;Junhao Zhao;Shuhong He;Aolong Sun;Xuyu Deng;Ouhan Huang;Jianyang Shi;Yingjun Zhou;Zhixue He;Nan Chi;Junwen Zhang","doi":"10.1364/JOCN.564562","DOIUrl":"https://doi.org/10.1364/JOCN.564562","url":null,"abstract":"This paper investigates the generation and impact of optical DC leakage in upstream burst-mode coherent TDM-PON systems. In upstream burst transmission, the laser remains on to avoid wavelength drift even when the optical network unit (ONU) is inactive, leading to the generation of residual DC leakage caused by a limited modulator extinction ratio and bias drift from the null point. As the number of ONUs increases, the accumulated optical DC leakage becomes large. In a more extreme case, where the optical signal comes from a distant ONU and all the other inactive ONUs are located close to the optical line terminal, the accumulated DC power can even exceed the signal power, resulting in SNR degradation and increased quantization noise. To address these challenges, we propose a flipped-frequency heterodyne detection scheme combined with SCM signaling. This approach upconverts the DC tones from low-frequency regions to high-frequency regions, allowing DC leakage to be effectively filtered out by the bandwidth-limited receiver before analog-to-digital conversion. As a proof of concept, we analyze the impact of DC leakage in both the time and frequency domains, compare the DC tolerance of PAM and SCM under different detection schemes, and support our findings with both simulation and experimental results. Finally, a 200G upstream simplified coherent TDM-PON system is experimentally demonstrated, showing up to 18 dB improvement in DC leakage tolerance compared to a baseband PAM4 signal at the 29 dB N1 class loss budget.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 1","pages":"A9-A18"},"PeriodicalIF":4.3,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145036847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}