Journal of Optical Communications and Networking最新文献

{"title":"BCFA: a bidirectional crosstalk- and fragmentation-aware resource allocation scheme in SDM-EONs","authors":"Bowen Bao;Yan Ding;Ming Wei;Guo Liu;Jiajia Zhao;Qiuyan Yao;Hui Yang;Bijoy Chand Chatterjee;Eiji Oki","doi":"10.1364/JOCN.591416","DOIUrl":"https://doi.org/10.1364/JOCN.591416","url":null,"abstract":"With the rapid evolution of emerging technologies, such as artificial intelligence, large-scale data centers, and 5G/6G communication systems, network traffic demands have increased significantly in both volume and asymmetry. Space-division multiplexing elastic optical networks (SDM-EONs), enabled by the abundant resources provided through multi-core fiber transmission, have been widely recognized as an effective solution for supporting high-capacity optical networks. By exploiting the inherent resource advantages of multi-core fiber architectures, SDM-EONs offer a scalable approach to capacity expansion. However, in SDM-EON environments, inter-core crosstalk (XT) and spectrum fragmentation introduce non-negligible signal impairments and degrade network performance. To address these issues, this paper proposes a bidirectional XT-aware impact (BXI) to evaluate the XT effects under bidirectional transmission. Based on this metric, a fragmentation measure is further incorporated to develop a bidirectional crosstalk- and fragmentation-aware metric (BCFM). Meanwhile, to ensure the quality of transmission, a bidirectional optical signal-to-noise ratio (OSNR) impairment evaluation model is introduced. Building upon these components, a novel, to our knowledge, bidirectional crosstalk- and fragmentation-aware (BCFA) resource allocation scheme is finally formulated. Based on bidirectional core assignment, the BCFA scheme jointly considers the impacts of XT and spectrum fragmentation to improve overall resource utilization, in which a novel, to our knowledge, bidirectional crosstalk and fragmentation-aware metric is defined. This metric quantitatively evaluates the influence of adjacent links on a given lightpath under bidirectional transmission conditions. The simulation results demonstrate that the BCFA scheme achieves substantial reductions in blocking probability with higher spectrum utilization.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"470-480"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737121","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":"Network-oriented metric for core pitch optimization in bidirectional multi-core fiber networks","authors":"Yuya Seki;Yosuke Tanigawa;Yusuke Hirota;Hideki Tode","doi":"10.1364/JOCN.579445","DOIUrl":"https://doi.org/10.1364/JOCN.579445","url":null,"abstract":"This study presents a framework for optimizing the core pitch of multi-core fibers (MCFs) in bidirectional MCF-based space-division multiplexing elastic optical networks (SDM-EONs). Existing studies have predominantly adopted hexagonal-lattice core layouts for the MCF structure and have overlooked indirect inter-core crosstalk (IC-XT), which can be the dominant impairment in bidirectional MCF-based SDM-EONs. In this study, existing IC-XT calculation models are re-evaluated, demonstrating that square-lattice-structure (SLS) MCFs are preferable for bidirectional MCF-based SDM-EONs, and an “XT-free condition” is derived to determine the optimal core pitch. Numerical simulations on three network topologies (EURO28, Kanto11, and TMN12) under multiple resource-allocation strategies reveal that the blocking probability is minimized whenever the XT-free condition is satisfied, independent of topology size or resource-allocation policy. For standard-cladding 4-core SLS MCFs, optimal core pitches (34.4, 34.0, and 30.7 µm) yield a minimum lightpath blocking probability, acceptable IC-XT, and ITU-T recommendation-compliant splicing loss. The proposed framework provides a general method for MCF design and offers valuable insights into realizing high-core-count MCF-based SDM-EONs. Beyond immediate design implications, the proposed framework may serve as a foundation for redefining benchmarking standards in resource-allocation models and guiding the future standardization of MCF designs.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"454-469"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737122","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":"Joint time-frequency domain feature exploitation for a single burst-mode preamble in a next-generation coherent optical access network","authors":"Jinqi Xiong;Yuheng Liu;Mingzhu Yin;Ji Zhou;Fan Li","doi":"10.1364/JOCN.587273","DOIUrl":"https://doi.org/10.1364/JOCN.587273","url":null,"abstract":"For the next-generation optical access network, where the data rate may achieve 200 Gb/s, conventional intensity modulation and direct detection (IM/DD) schemes will face significant challenges. Coherent optical communication is considered a promising solution for next-generation optical access networks. However, conventional blind coherent digital signal processing (DSP) demonstrates insufficient convergence speed to fulfill burst-mode detection requirements. Designing specialized preamble sequences is an effective solution for simplifying coherent burst-mode DSP. This paper proposes an efficient preamble structure with a duration of 8.25 ns. The proposed preamble fully utilizes the frequency-domain and time-domain properties of the sequence, enabling chromatic dispersion (CD) estimation and clock recovery in the frequency-domain, while achieving frame synchronization, frequency offset estimation (FOE), and state of polarization (SOP) estimation in the time-domain. This allows the proposed scheme to achieve rapid CD estimation without introducing additional preamble overhead. We established a 32 GBaud dual-polarization 16-quadrature amplitude modulation (DP-16QAM) system incorporating the proposed scheme, and experimentally validated the effectiveness of the proposed preamble and the corresponding burst-mode DSP scheme. The proposed scheme provides a feasible solution for next-generation optical access networks.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"433-441"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147696638","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":"Solar-outage-based SRLG and protection in optical satellite networks","authors":"Yansong Fu;Yongli Zhao;Wei Wang;Meng Lian;Zijian Cui;Ruikang Ni;Jie Zhang","doi":"10.1364/JOCN.582989","DOIUrl":"https://doi.org/10.1364/JOCN.582989","url":null,"abstract":"Optical satellite networks (OSNs) are advancing at an impressive pace, but ensuring their reliability remains a significant challenge. Unlike terrestrial optical networks, many of the problems faced in optical satellite networks are unique. For example, in the case of a solar outage, some laser links will not be able to communicate. These events occur frequently and can vary on a minute-by-minute scale. Traditional <tex>$1 + 1$</tex> dedicated protection can effectively protect against single-link failures. However, sun outages simultaneously affect multiple links near the day–night terminator, which may cause protection failure. For regional failures under <tex>$1 + 1$</tex> protection, constructing shared risk link groups (SRLGs) is commonly used to avoid such failures. Unlike terrestrial networks, though, the failure regions in satellite networks are constantly shifting from the network’s perspective, which poses new challenges for survivability design. In this paper, we propose a shared risk link group (SRLG) model based on solar outage to define the joint risk caused by the sun outage region. Accordingly, we further propose an SRLG-constrained dedicated path protection (SRLG-DP) algorithm. SRLG-DP defines a protection window to avoid excessive detours and identifies SRLG-disjoint paths within the network. Simulation results demonstrate that SRLG-DP maintains high transmission success rates even under reduced prediction accuracy, along with relatively low path delay and delay jitter.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"500-511"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796151","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":"Bidirectional and crossed AWGR-based interconnection for large-scale data centers","authors":"Yang Lu;Alami Badreddine;Minghao Yan;Jiaqing Liu;Zihui Lin;Jiawei Lv;Yunxin Lv;Meihua Bi;Miao Hu","doi":"10.1364/JOCN.581779","DOIUrl":"https://doi.org/10.1364/JOCN.581779","url":null,"abstract":"A novel, to our knowledge, bidirectional and crossed interconnection (BCI) based on array waveguide grating routers (AWGRs) is proposed for the data centers of large scale. In BCI, the AWGRs are crossed interconnected, and the transmissions are bidirectional. <tex>$Ntimes(N + 1)$</tex> nodes can be interconnected with <tex>$N + 1$</tex> <tex>$N$</tex>-port AWGRs and <tex>$N$</tex> available wavelengths. The throughput depends on the communication patterns, as some communications need multiple hops. The expected value of average hops is analyzed and reduced by some methods. The proposed BCI is more cost-effective compared to previous proposals. The physical transmission in BCI is demonstrated by simulation, and the tested results show the feasibility of the signal transmissions in BCI.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"424-432"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147696213","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":"ALAS-DCN: application-aware low-latency scalable data center network architecture for intra-rack and inter-rack optical packet switching","authors":"Georgios Drainakis;Peristera Baziana;Adonis Bogris","doi":"10.1364/JOCN.575115","DOIUrl":"https://doi.org/10.1364/JOCN.575115","url":null,"abstract":"Data center networks (DCNs) are at the forefront of a radical transformation, fueled by the rapid rise of artificial intelligence (AI), cloud-native adoption, and enterprise digitalization, which together place unprecedented demands on their design and performance. From healthcare AI and intelligent transportation to business analytics, modern DCNs are expected to support a diverse and evolving mix of bandwidth-demanding applications, each with distinct quality of service (QoS) requirements. Yet, most state-of-the-art DCN solutions rely on oversimplified DCN data traffic models, failing to address the required application-level differentiation in terms of end-to-end (E2E) latency demands. In response, we propose ALAS-DCN, a novel, to our knowledge, application-aware, low-latency, scalable DCN architecture, based on optical packet switching in the intra-rack and inter-rack domains that is both designed and rigorously evaluated using commercial QoS specifications and realistic traffic patterns of different applications coexisting within the same DCN. ALAS-DCN integrates three hierarchical optical sub-networks: intra-rack, inter-rack, and bridge, each governed by a custom wavelength division multiplexing (WDM) medium access control (MAC) protocol that dynamically prioritizes critical traffic packets, according to the specific application E2E latency demands. Unlike prior approaches, our evaluation leverages realistic workload traces generated by established traffic generators, capturing the application diversity within modern data center (DC) environments. Extensive experimental simulations across five representative DC categories, each hosting a different mix of modern applications, demonstrate that ALAS-DCN consistently achieves up to 95% throughput efficiency and <tex>$text{sub}{{text-}{unicode{x00B5}}text s}$</tex> latency for high priority traffic across a variety of applications, consistently meeting their differentiated latency constraints. Scalable up to 20,000 servers, ALAS-DCN redefines the DCN as not just a transport layer but an intelligent enabler of next-generation application performance.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"409-423"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665540","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":"Field trial of 240  km decentralized training with separation of compute and data based on PFC-assisted hitless 800G OTN","authors":"Shan Cao;Dechao Zhang;Xiaodong Duan;Dong Wang;Bin Fan;Jiang Sun;Mingqing Zuo;Bin Qi;Han Li","doi":"10.1364/JOCN.589613","DOIUrl":"https://doi.org/10.1364/JOCN.589613","url":null,"abstract":"A novel, to our knowledge, PFC-assisted hitless OTN for separation of compute and data is proposed and demonstrated. Based on the new scheme, simulations are conducted and analyzed comprehensively. Simulations indicate that symmetric or asymmetric computing power distribution minimally affects efficiency. With consistent GPUs, larger models experience less impact from remote extension. When training with an appropriate number of GPUs compatible with the model, the degradation rate of training efficiency for models of different sizes remains comparable as the distance increases. Then, the effectiveness of the PFC-assisted hitless OTN is experimentally verified. By hitless protection, pipeline parallelism training efficiency is free from the switchover between primary and backup paths. With the PFC function on, the training efficiency could be improved from 52% to 99.51% over 120 km transmission, compared to the off case. Furthermore, different model sizes, transmission distances, and network convergence ratios are experimentally investigated by the field trial. When extending to 240 km, training efficiency is still up to 99.29%.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"492-499"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796220","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":"Expertise-guided LLM agent for autonomous optical power optimization in field-deployed optical networks","authors":"Qizhi Qiu;Yihao Zhang;Xiaomin Liu;Siyuan Wu;Lilin Yi;Weisheng Hu;Qunbi Zhuge","doi":"10.1364/JOCN.588873","DOIUrl":"https://doi.org/10.1364/JOCN.588873","url":null,"abstract":"Artificial intelligence (AI) agents powered by large language models (LLMs) are regarded as a prospective solution for autonomous optical power optimization in optical networks. In this paper, we develop an AI agent that incorporates human expertise, including physical knowledge, optimization knowledge, and optimization workflow. Leveraging provided toolsets, the AI agent explores the configuration space with a digital twin (DT) and deploys selected configurations on the actual network. Following an expertise-guided workflow comprising DT exploration, online evaluation, and fine-tuning, the AI agent performs efficient and reliable optical power optimization in a field-deployed network. Field-trial results show that the expertise-guided AI agent reaches the target quality of transmission (QoT) with an average of only 5.9 adjustments. Under the same scenario, Bayesian optimization (BO) and a genetic algorithm (GA) require <tex>$5.8times$</tex> and <tex>$27.9times$</tex> as many adjustments, respectively. The AI agent also ensures a reliable optimization process by maintaining a Q-factor margin of greater than 4 dB at each adjustment, whereas BO and GA fall below the forward error correction (FEC) threshold. Additionally, the expertise-guided AI agent delivers superior optimization across different wavelength-loading scenarios, demonstrating its capability to generalize across varying channel loads. Consequently, the expertise-guided AI agent provides a promising approach for autonomous, efficient, and reliable optical power optimization in future autonomous optical networks.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"481-491"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737194","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":"Adaptive QKD link establishment for single- and dual-layer LEO quantum satellite networks","authors":"Xu Zhang;Yuan Cao;Xiangyu Chen;Bingran Geng;Zhuangzhuang Ma;Jingjing Liu;Kunpeng Zheng;Yazi Wang;Mingxuan Guo;Xiaosong Yu;Yongli Zhao","doi":"10.1364/JOCN.589327","DOIUrl":"https://doi.org/10.1364/JOCN.589327","url":null,"abstract":"Satellite-based quantum key distribution (QKD), especially relying on low Earth orbit (LEO) satellites, overcomes the geographical limitations of fiber-based QKD and enables global secure communications. However, existing QKD link establishment schemes for LEO quantum satellite networks fail to fully consider practical scenarios (e.g., multi-layer constellations as well as heterogeneous satellite–ground and inter-satellite QKD links) along with realistic constraints (e.g., different illumination conditions and the need to avoid frequent link switching). To address this gap, this work focuses on the adaptive establishment of satellite–ground and inter-satellite QKD links in single- and dual-layer LEO quantum satellite networks. We describe the network structures of single- and dual-layer constellations, as well as formulate the corresponding network model, secret key rate model, and secret key volume model. To realize adaptive QKD link establishment, we develop two integer linear programming (ILP) models and design three heuristic algorithms. The two ILP models are denoted as ILP-G and ILP-R, respectively, where ILP-G aims to maximize the generated key volume, and ILP-R is dedicated to optimizing global key resource balance by prioritizing QKD links with lower remaining key volume. The three heuristic algorithms are designed based on maximum key rate (MaxKR), maximum generated key volume (MaxGKV), and minimum remaining key volume (MinRKV). Simulation results verify the applicability of the proposed approaches across single- and dual-layer LEO quantum satellite networks. Comparative evaluations against two benchmarks, i.e., random fit (RF) and first fit (FF), show that ILP-G and MaxGKV achieve the largest cumulative key volume, while ILP-R and MinRKV outperform the other approaches in key volume distribution, quantum satellite availability, and total number of established QKD links. Specifically, the cumulative key volume of ILP-G is 44.0% and 33.8% higher than that of RF in single- and dual-layer LEO quantum satellite networks, respectively. Furthermore, the dual-layer constellation generates more key resources, with the cumulative key volume reaching approximately five times that of the single-layer constellation. It also exhibits a more balanced global key resource distribution, where key resources are distributed across a broader set of node pairs rather than concentrated on a limited subset of nodes.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"536-552"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796149","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":"Intra-PON communication based on DSCM coherent-PON for ultra-low latency 5G/6G X-haul services","authors":"Safana Al zoubi;Alessandro Galardini;Roberto Gaudino","doi":"10.1364/JOCN.578877","DOIUrl":"https://doi.org/10.1364/JOCN.578877","url":null,"abstract":"Future passive optical networks (PONs) are expected to support the ultra-high bitrates and extremely low-latency requirements of X-haul networks. In parallel, many research groups and standardization bodies are investigating PON transmission solutions for 100+ Gbps per wavelength (very high speed PON or VHSP), considering also the introduction of coherent transmission technologies in PON. Building on these two trends, we propose and analytically investigate simple physical modifications to the standard PON infrastructures to enable direct all-optical ONU-to-ONU communications, showing their rationale for X-haul. We introduce both intra- and inter-PON ONU-to-ONU all-optical configurations and assess their impact on optical distribution network (ODN) loss, considering current and future-compliant transceivers. We focus in particular on coherent PON based on digital subcarrier multiplexing (DSCM), which is one of the solutions currently investigated by the ITU-T for VHSP. Our analysis shows that, under reasonable assumptions for future PON-complaint DSCM-based transceivers, the proposed architectures can support 40 km ONU-to-ONU links with an additional allowed loss margin of about 1.3 dB beyond the 29 dB N1 PON class limit, and one ONU to four ONU connections with only 2 dB of extra margin. Furthermore, the proposed architectures achieve significant latency reductions, making them suitable for future low-latency split- and service-based transport requirements.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 5","pages":"442-453"},"PeriodicalIF":4.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147696156","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}