Huitao Zhou;Lizhu Liu;Chen Su;Bojun Zhang;Zhiqun Gu;Jiawei Zhang;Yuefeng Ji
The rise of time-sensitive applications has intensified the need for deterministic transmission across networks. As computing and service functions are shifted toward the edge, metro networks have become the key interconnection layer between access and core domains. However, conventional optoelectronic-switched network architectures, which rely on statistical multiplexing and slow reconfiguration, fail to meet stringent latency and jitter constraints. To overcome these challenges, this paper focuses on a scalable all-optical spine-leaf network architecture by introducing an optical time-slot switching (OTS) framework. OTS offers fine-grained switching and low-latency transmission; however, achieving deterministic transmission over shared optical resources remains challenging due to slot contention and insufficient coordination in existing scheduling schemes. Therefore, we propose a time-aware wavelength and slot allocation (TA-SA) scheme that allocates transmission windows (TWs) according to individual flow parameters, including arrival time, period, and jitter tolerance. We formulate an integer linear programming model and a heuristic algorithm to jointly optimize TW placement and wavelength-slot mapping under strict QoS constraints. To analyze worst-case network performance, deterministic network calculus is adopted to model delay and backlog bounds for different scheduling schemes. Simulation results show that TA-SA not only guarantees end-to-end latency and jitter constraints but also improves average resource utilization by over 34.9% compared to the existing scheduling schemes. Moreover, the proposed scheme significantly reduces buffer occupancy under increasing traffic loads, demonstrating its scalability and effectiveness for deterministic transmission in metro all-optical networks.
{"title":"Deterministic optical time-slot scheduling and performance evaluation via time-aware resource allocation in metro all-optical spine-leaf networks","authors":"Huitao Zhou;Lizhu Liu;Chen Su;Bojun Zhang;Zhiqun Gu;Jiawei Zhang;Yuefeng Ji","doi":"10.1364/JOCN.577375","DOIUrl":"https://doi.org/10.1364/JOCN.577375","url":null,"abstract":"The rise of time-sensitive applications has intensified the need for deterministic transmission across networks. As computing and service functions are shifted toward the edge, metro networks have become the key interconnection layer between access and core domains. However, conventional optoelectronic-switched network architectures, which rely on statistical multiplexing and slow reconfiguration, fail to meet stringent latency and jitter constraints. To overcome these challenges, this paper focuses on a scalable all-optical spine-leaf network architecture by introducing an optical time-slot switching (OTS) framework. OTS offers fine-grained switching and low-latency transmission; however, achieving deterministic transmission over shared optical resources remains challenging due to slot contention and insufficient coordination in existing scheduling schemes. Therefore, we propose a time-aware wavelength and slot allocation (TA-SA) scheme that allocates transmission windows (TWs) according to individual flow parameters, including arrival time, period, and jitter tolerance. We formulate an integer linear programming model and a heuristic algorithm to jointly optimize TW placement and wavelength-slot mapping under strict QoS constraints. To analyze worst-case network performance, deterministic network calculus is adopted to model delay and backlog bounds for different scheduling schemes. Simulation results show that TA-SA not only guarantees end-to-end latency and jitter constraints but also improves average resource utilization by over 34.9% compared to the existing scheduling schemes. Moreover, the proposed scheme significantly reduces buffer occupancy under increasing traffic loads, demonstrating its scalability and effectiveness for deterministic transmission in metro all-optical networks.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 1","pages":"59-73"},"PeriodicalIF":4.3,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026439","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}
This tutorial paper presents a survey on several current ongoing research activities about the expected evolution of passive optical networks, focusing on the physical layer (i.e., on the physical media dependent or PMD layer). After the recent public release of the ITU-T G.9804.3 50G-PON standard, there is today ongoing extensive scientific brainstorming on what can be the best optical transmission solutions for the PON “next step,” which will likely be targeting 100G or 200G per wavelength per direction. Elaborating on our OFC2025 tutorial on these topics, we start with a brief overview of the possible IM-DD solutions and their actual limitations for 200G-PON, while the core of the paper discusses the pros and cons of the introduction of advanced modulation formats and coherent detection also in PON, including some hybrid solutions that are currently under investigation in the ITU-T Very High Speed PON initiative. We show that coherent PON can actually reach the 200G per wavelength target, including some spare link budget margin, which can potentially be used for new access architectures. As an example, we present a summary of our recent results on hybrid solutions and on the all-optical convergence between the metro and access segments.
{"title":"High-speed PON solutions: recent evolutions and expected trends [Invited Tutorial]","authors":"Giuseppe Rizzelli;Roberto Gaudino","doi":"10.1364/JOCN.575601","DOIUrl":"https://doi.org/10.1364/JOCN.575601","url":null,"abstract":"This tutorial paper presents a survey on several current ongoing research activities about the expected evolution of passive optical networks, focusing on the physical layer (i.e., on the physical media dependent or PMD layer). After the recent public release of the ITU-T G.9804.3 50G-PON standard, there is today ongoing extensive scientific brainstorming on what can be the best optical transmission solutions for the PON “next step,” which will likely be targeting 100G or 200G per wavelength per direction. Elaborating on our OFC2025 tutorial on these topics, we start with a brief overview of the possible IM-DD solutions and their actual limitations for 200G-PON, while the core of the paper discusses the pros and cons of the introduction of advanced modulation formats and coherent detection also in PON, including some hybrid solutions that are currently under investigation in the ITU-T Very High Speed PON initiative. We show that coherent PON can actually reach the 200G per wavelength target, including some spare link budget margin, which can potentially be used for new access architectures. As an example, we present a summary of our recent results on hybrid solutions and on the all-optical convergence between the metro and access segments.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 2","pages":"A134-A149"},"PeriodicalIF":4.3,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026451","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}
The quantum noise stream cipher (QNSC) scheme, grounded in Heisenberg’s uncertainty principle, can facilitate secure communication by employing noise to obfuscate multi-base encrypted signals. The current research primarily focuses on point-to-point performance, while studies on point-to-multipoint schemes remain limited due to compatibility issues with multiple access technologies. This study presents a QNSC scheme for passive optical networks based on code-division multiple access (CDMA). In our scheme, different user datasets are combined into one dataset via CDMA and then encrypted using the QNSC protocol. Each user can recover their corresponding dataset from the encrypted signal by employing the same security keys along with a distinct pseudo-noise code (PN code). Through simulation studies, we found that under the condition of being able to decode correctly, as the number of users increases, the optical signal-to-noise ratio (OSNR) at the receiver decreases, which leads to a gradual rise in the eavesdropper’s detection failure probability (DFP). Furthermore, the network capacity is correlated with the number of modulation bits, as the increase in modulation bits directly translates to an enhancement in the data’s carrying capability. We have conducted verification experiments, and the results confirmed that four users can acquire 64 QAM/QNSC plaintext data with an average transmission rate of 600 Mbit/s over a transmission distance of 20 km. These data were encrypted in the constellation with $64times 64$ symbols, achieving a DFP of up to 99.3%, and each user successfully decoded them via CDMA. We have successfully extended the fundamental point-to-point QNSC scheme to accommodate point-to-multipoint passive optical networks, establishing the foundational framework for the future large-scale deployment of quantum networks.
{"title":"CDMA-based quantum noise stream cipher for passive optical networks","authors":"Yuchao Liu;Tao Wang;Lang Li;Yuehan Xu;Xu Liu;Yankai Xu;Beibei Zhang;Peng Huang;Guihua Zeng","doi":"10.1364/JOCN.565150","DOIUrl":"https://doi.org/10.1364/JOCN.565150","url":null,"abstract":"The quantum noise stream cipher (QNSC) scheme, grounded in Heisenberg’s uncertainty principle, can facilitate secure communication by employing noise to obfuscate multi-base encrypted signals. The current research primarily focuses on point-to-point performance, while studies on point-to-multipoint schemes remain limited due to compatibility issues with multiple access technologies. This study presents a QNSC scheme for passive optical networks based on code-division multiple access (CDMA). In our scheme, different user datasets are combined into one dataset via CDMA and then encrypted using the QNSC protocol. Each user can recover their corresponding dataset from the encrypted signal by employing the same security keys along with a distinct pseudo-noise code (PN code). Through simulation studies, we found that under the condition of being able to decode correctly, as the number of users increases, the optical signal-to-noise ratio (OSNR) at the receiver decreases, which leads to a gradual rise in the eavesdropper’s detection failure probability (DFP). Furthermore, the network capacity is correlated with the number of modulation bits, as the increase in modulation bits directly translates to an enhancement in the data’s carrying capability. We have conducted verification experiments, and the results confirmed that four users can acquire 64 QAM/QNSC plaintext data with an average transmission rate of 600 Mbit/s over a transmission distance of 20 km. These data were encrypted in the constellation with <tex>$64times 64$</tex> symbols, achieving a DFP of up to 99.3%, and each user successfully decoded them via CDMA. We have successfully extended the fundamental point-to-point QNSC scheme to accommodate point-to-multipoint passive optical networks, establishing the foundational framework for the future large-scale deployment of quantum networks.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 2","pages":"74-82"},"PeriodicalIF":4.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982273","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}
Coherent passive optical networks (PONs) have emerged as a promising candidate for next-generation access networks due to their superior receiver sensitivity, high data rates, extended reach, and enhanced flexibility. However, their large-scale deployment is hindered by the complexity and cost of coherent receivers, particularly at the optical network unit (ONU). In this work, we propose and experimentally demonstrate a flexible 200 Gb/s coherent time-and-frequency-division multiple access PON for the downstream, leveraging a simplified ONU architecture and a low-cost MHz-linewidth distributed feedback (DFB) laser. A tailored subcarrier allocation scheme is introduced to enable heterodyne detection with polarization diversity, supporting flexible-rate reception of single or multiple subcarriers via local oscillator (LO) wavelength tuning. Efficient carrier recovery is achieved through pilot-tone-aided digital signal processing, eliminating the need for time-domain pilot symbols and significantly reducing frame overhead. We experimentally demonstrate flexible data rate reception from 50 to 200 Gb/s. A power budget exceeding 32.5 dB is achieved after 25 km standard single-mode fiber transmission using a 1 MHz linewidth DFB LO and a 512-symbol preamble, showcasing high sensitivity and robust performance. This work paves the way for the practical deployment of cost-effective coherent PON systems.
{"title":"200G coherent TFDMA PON with flexible subcarrier reception based on a low-cost ONU [Invited]","authors":"Yixiao Zhu;Xingang Huang;Xiansong Fang;Xiatao Huang;Ziheng Zhang;Xiang Cai;Guoqiang Li;Lina Man;Guangying Yang;Yimin Hu;Yiming Zhong;Fan Zhang;Weisheng Hu","doi":"10.1364/JOCN.573289","DOIUrl":"https://doi.org/10.1364/JOCN.573289","url":null,"abstract":"Coherent passive optical networks (PONs) have emerged as a promising candidate for next-generation access networks due to their superior receiver sensitivity, high data rates, extended reach, and enhanced flexibility. However, their large-scale deployment is hindered by the complexity and cost of coherent receivers, particularly at the optical network unit (ONU). In this work, we propose and experimentally demonstrate a flexible 200 Gb/s coherent time-and-frequency-division multiple access PON for the downstream, leveraging a simplified ONU architecture and a low-cost MHz-linewidth distributed feedback (DFB) laser. A tailored subcarrier allocation scheme is introduced to enable heterodyne detection with polarization diversity, supporting flexible-rate reception of single or multiple subcarriers via local oscillator (LO) wavelength tuning. Efficient carrier recovery is achieved through pilot-tone-aided digital signal processing, eliminating the need for time-domain pilot symbols and significantly reducing frame overhead. We experimentally demonstrate flexible data rate reception from 50 to 200 Gb/s. A power budget exceeding 32.5 dB is achieved after 25 km standard single-mode fiber transmission using a 1 MHz linewidth DFB LO and a 512-symbol preamble, showcasing high sensitivity and robust performance. This work paves the way for the practical deployment of cost-effective coherent PON systems.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 2","pages":"A100-A111"},"PeriodicalIF":4.3,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808557","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}
Very high speed PON is the PON generation in the ITU-T that is coming after 50G-PON. It is currently in the exploratory study phase in ITU, with network operators sharing their views on potential requirements and the Q2/SG15 group proposing and evaluating technology candidates to meet these requirements. This paper reviews the progress so far in identifying the key requirements, technical candidates, physical layer transmission performance, and the related technology maturity. The paper discusses the technology candidate evaluation process underway as part of this pre-standardization, research phase of very high speed PON among the relevant standards experts within FSAN and ITU-T SG15/Q2.
{"title":"Progress of Very High Speed PON in ITU-T [Invited]","authors":"Dezhi Zhang;Dekun Liu;Derek Nesset","doi":"10.1364/JOCN.573747","DOIUrl":"https://doi.org/10.1364/JOCN.573747","url":null,"abstract":"Very high speed PON is the PON generation in the ITU-T that is coming after 50G-PON. It is currently in the exploratory study phase in ITU, with network operators sharing their views on potential requirements and the Q2/SG15 group proposing and evaluating technology candidates to meet these requirements. This paper reviews the progress so far in identifying the key requirements, technical candidates, physical layer transmission performance, and the related technology maturity. The paper discusses the technology candidate evaluation process underway as part of this pre-standardization, research phase of very high speed PON among the relevant standards experts within FSAN and ITU-T SG15/Q2.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 2","pages":"A112-A122"},"PeriodicalIF":4.3,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11313654","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mingshuo Sun;Ziqi Chen;Haoran Shen;Jian Li;Xingyu Zhou;Chunhui Zhang;Qin Wang
Nowadays, quantum key distribution (QKD) has gradually moved from the laboratory to practical applications. However, the inherent imperfections of practical QKD devices would cause side channels. Among them, there is one critical side channel vulnerability that is often overlooked, i.e., information leakage of the electromagnetic field (LEMF). In this work, we carry out systematic investigations on the LEMF by utilizing a practical phase-coding BB84 QKD system as an example. We demonstrate that LEMF from the widely used modulators could be exploited by a malicious eavesdropper to obtain corresponding encoding information assisted with artificial intelligence algorithms, posing a serious threat for practical QKD systems. To solve this problem, we conduct security analysis on LEMF and build a mathematical model on the final secure key rate. Moreover, we give out corresponding countermeasures to reduce information leakage and thus enhance practical security of QKD systems. Therefore, our current work can provide important theoretical and experimental foundations for the future development of secure large-scale quantum communication networks.
{"title":"Attacks and countermeasures against electromagnetic field information leakage from quantum cryptography networks","authors":"Mingshuo Sun;Ziqi Chen;Haoran Shen;Jian Li;Xingyu Zhou;Chunhui Zhang;Qin Wang","doi":"10.1364/JOCN.579812","DOIUrl":"https://doi.org/10.1364/JOCN.579812","url":null,"abstract":"Nowadays, quantum key distribution (QKD) has gradually moved from the laboratory to practical applications. However, the inherent imperfections of practical QKD devices would cause side channels. Among them, there is one critical side channel vulnerability that is often overlooked, i.e., information leakage of the electromagnetic field (LEMF). In this work, we carry out systematic investigations on the LEMF by utilizing a practical phase-coding BB84 QKD system as an example. We demonstrate that LEMF from the widely used modulators could be exploited by a malicious eavesdropper to obtain corresponding encoding information assisted with artificial intelligence algorithms, posing a serious threat for practical QKD systems. To solve this problem, we conduct security analysis on LEMF and build a mathematical model on the final secure key rate. Moreover, we give out corresponding countermeasures to reduce information leakage and thus enhance practical security of QKD systems. Therefore, our current work can provide important theoretical and experimental foundations for the future development of secure large-scale quantum communication networks.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 1","pages":"27-34"},"PeriodicalIF":4.3,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830975","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}
Christos Christofidis;Alberto Otero-Casado;Pablo Torres-Ferrera;Dan M. Marom;Giuseppe Parisi;Antonio Napoli;Paolo Monti;Ioannis Tomkos
The evolution of passive optical networks (PONs) is rapidly progressing, with the next generation aiming to surpass $100 ;{rm Gb/s}/lambda$ and target $200 ;{rm Gb/s}/lambda$—a typical fourfold increase over the current $50 ;{rm Gb/s}/lambda$ power splitter (PS)-based PON standard. This paper outlines current research and development challenges in PONs and explores potential advancements using programmable photonic Nyquist-shaped Interleaver (NS-INT) filters paired with coherent point-to-multipoint (P2MP) digital subcarrier multiplexing (DSCM) transceivers. Specifically, we evaluated, based on analytical estimations and simulations, two NS-INT implementations for mobile transport: one based on ring resonators-assisted filters and a second utilizing an optical 18-tap cascaded asymmetric Mach–Zehnder Interferometer (aMZI). We compare their effectiveness in optimizing filtering and minimizing crosstalk (XT) across various coupling coefficient scenarios. Furthermore, we assess the feasibility of these designs by examining their performance under XT and signal impairment caused by filter narrowing effects, particularly in the presence of signal-to-filter center frequency misalignment. Bit error rate (BER) evaluations demonstrate a tolerance to frequency misalignments of up to 3 GHz across all architectures. Among them, our cascaded aMZI design exhibits superior performance, attributed to its inherent optical finite impulse response (FIR) filter characteristics as a minimum-phase filter.
{"title":"Performance assessment of interleaver filters for next-generation mobile transport","authors":"Christos Christofidis;Alberto Otero-Casado;Pablo Torres-Ferrera;Dan M. Marom;Giuseppe Parisi;Antonio Napoli;Paolo Monti;Ioannis Tomkos","doi":"10.1364/JOCN.575589","DOIUrl":"https://doi.org/10.1364/JOCN.575589","url":null,"abstract":"The evolution of passive optical networks (PONs) is rapidly progressing, with the next generation aiming to surpass <tex>$100 ;{rm Gb/s}/lambda$</tex> and target <tex>$200 ;{rm Gb/s}/lambda$</tex>—a typical fourfold increase over the current <tex>$50 ;{rm Gb/s}/lambda$</tex> power splitter (PS)-based PON standard. This paper outlines current research and development challenges in PONs and explores potential advancements using programmable photonic Nyquist-shaped Interleaver (NS-INT) filters paired with coherent point-to-multipoint (P2MP) digital subcarrier multiplexing (DSCM) transceivers. Specifically, we evaluated, based on analytical estimations and simulations, two NS-INT implementations for mobile transport: one based on ring resonators-assisted filters and a second utilizing an optical 18-tap cascaded asymmetric Mach–Zehnder Interferometer (aMZI). We compare their effectiveness in optimizing filtering and minimizing crosstalk (XT) across various coupling coefficient scenarios. Furthermore, we assess the feasibility of these designs by examining their performance under XT and signal impairment caused by filter narrowing effects, particularly in the presence of signal-to-filter center frequency misalignment. Bit error rate (BER) evaluations demonstrate a tolerance to frequency misalignments of up to 3 GHz across all architectures. Among them, our cascaded aMZI design exhibits superior performance, attributed to its inherent optical finite impulse response (FIR) filter characteristics as a minimum-phase filter.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 1","pages":"16-26"},"PeriodicalIF":4.3,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830931","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}
The continuous growth in traffic demand across metro and core networks is driving operators to adopt cost-effective and sustainable strategies. A promising solution is the deployment of IP-over-WDM (IPoWDM) networks using coherent ZR+ pluggable transceivers connected to high-capacity elastic optical networks. This approach eliminates the need for traditional external transponders, reducing cost, power consumption, and equipment footprint. To enhance sustainability in IPoWDM infrastructures, energy-aware routing, modulation, and spectrum assignment (EA-RMSA) algorithms are crucial for dynamically provisioning connectivity service requests. Traditionally, EA-RMSA has been implemented using heuristics, such as $K$ shortest-path first-fit, aiming to minimize power consumption by accommodating requests on already active devices via a sleep mode strategy. To further improve energy efficiency (i.e., power consumption per throughput), we propose a novel, to the best of our knowledge, deep reinforcement learning-based EA-RMSA solution, referred to as DRL KSP. The trained DRL agent adapts to varying network conditions and learns optimized energy-efficient policies. Performance evaluation under two scenarios with different transceiver configurations and traffic loads shows that DRL EA-KSP achieves power savings up to 7.4% and energy efficiency improvements up to 6.6% compared to heuristic methods. These gains, however, come at the cost of reducing average network throughput by up to 2%, highlighting a trade-off between sustainability and performance. This enables operators to tailor strategies according to their operational goals.
{"title":"Deep reinforcement learning for energy-efficient RMSA in IPoWDM networks with coherent ZR+ transceivers [Invited]","authors":"Ricardo Martinez;Carlos Hernandez-Chulde;Ramon Casellas;Ricard Vilalta;Raul Munoz","doi":"10.1364/JOCN.574251","DOIUrl":"https://doi.org/10.1364/JOCN.574251","url":null,"abstract":"The continuous growth in traffic demand across metro and core networks is driving operators to adopt cost-effective and sustainable strategies. A promising solution is the deployment of IP-over-WDM (IPoWDM) networks using coherent ZR+ pluggable transceivers connected to high-capacity elastic optical networks. This approach eliminates the need for traditional external transponders, reducing cost, power consumption, and equipment footprint. To enhance sustainability in IPoWDM infrastructures, energy-aware routing, modulation, and spectrum assignment (EA-RMSA) algorithms are crucial for dynamically provisioning connectivity service requests. Traditionally, EA-RMSA has been implemented using heuristics, such as <tex>$K$</tex> shortest-path first-fit, aiming to minimize power consumption by accommodating requests on already active devices via a sleep mode strategy. To further improve energy efficiency (i.e., power consumption per throughput), we propose a novel, to the best of our knowledge, deep reinforcement learning-based EA-RMSA solution, referred to as DRL KSP. The trained DRL agent adapts to varying network conditions and learns optimized energy-efficient policies. Performance evaluation under two scenarios with different transceiver configurations and traffic loads shows that DRL EA-KSP achieves power savings up to 7.4% and energy efficiency improvements up to 6.6% compared to heuristic methods. These gains, however, come at the cost of reducing average network throughput by up to 2%, highlighting a trade-off between sustainability and performance. This enables operators to tailor strategies according to their operational goals.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 2","pages":"A123-A133"},"PeriodicalIF":4.3,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808637","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}
YeongJun Seok;Ihsan Ullah;Youn-Hee Han;Chankyun Lee;Wonhyuk Lee
Quantum networks represent promising foundations for secure communication, distributed quantum computing, and advanced quantum-enabled services. However, their deployment faces practical challenges including limited quantum resources, short coherence times, and environmental disturbances. Effective end-to-end entanglement request scheduling is critical to addressing these challenges, as it directly affects resource utilization and network reliability. Although end-to-end entanglement service rate is one of the representative performance measures in the quantum networks, the explicit optimization of the rate under the realistic constraints is relatively unexplored in the previous studies. This paper proposes an offline reinforcement learning (RL)-based scheduling framework, employing a decision transformer integrated with graph attention networks, to specifically optimize service rates within practical operational constraints, such as the single-time-slot usage limitation of quantum links. Our approach adaptively leverages network topology and operational dynamics to enhance scheduling decisions. Simulation studies conducted on the NetSquid platform across four quantum network topologies demonstrate that our model consistently outperforms both a conventional rule-based method and a baseline offline RL method in terms of service rate, while preserving fidelity and maintaining delays within acceptable levels. These results confirm the effectiveness of the proposed method for practical quantum network management.
{"title":"End-to-end entanglement request scheduling in quantum networks via topology-aware decision transformer","authors":"YeongJun Seok;Ihsan Ullah;Youn-Hee Han;Chankyun Lee;Wonhyuk Lee","doi":"10.1364/JOCN.569435","DOIUrl":"https://doi.org/10.1364/JOCN.569435","url":null,"abstract":"Quantum networks represent promising foundations for secure communication, distributed quantum computing, and advanced quantum-enabled services. However, their deployment faces practical challenges including limited quantum resources, short coherence times, and environmental disturbances. Effective end-to-end entanglement request scheduling is critical to addressing these challenges, as it directly affects resource utilization and network reliability. Although end-to-end entanglement service rate is one of the representative performance measures in the quantum networks, the explicit optimization of the rate under the realistic constraints is relatively unexplored in the previous studies. This paper proposes an offline reinforcement learning (RL)-based scheduling framework, employing a decision transformer integrated with graph attention networks, to specifically optimize service rates within practical operational constraints, such as the single-time-slot usage limitation of quantum links. Our approach adaptively leverages network topology and operational dynamics to enhance scheduling decisions. Simulation studies conducted on the NetSquid platform across four quantum network topologies demonstrate that our model consistently outperforms both a conventional rule-based method and a baseline offline RL method in terms of service rate, while preserving fidelity and maintaining delays within acceptable levels. These results confirm the effectiveness of the proposed method for practical quantum network management.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 1","pages":"1-15"},"PeriodicalIF":4.3,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830971","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}
Scalable and efficient methods for predicting optical transmission performance using machine learning (ML) and cascaded learning (CL) are investigated in metro multi-span optical networks. We extend the CL framework beyond multi-span power spectrum prediction to enable accurate estimation of optical signal-to-noise (OSNR) and generalized signal-to-noise (GSNR) under dynamic channel loading, integrating cascaded component models for end-to-end (E2E) optical link performance prediction. To mitigate error accumulation inherent in cascaded predictions, additional E2E optical link measurements and models are incorporated. To ensure scalability, component-level models for erbium-doped fiber amplifier (EDFA) gain and noise figure are pre-trained prior to deployment. We demonstrate that the data collection effort for pre-training the EDFA model can be reduced to only 5.5% of the original training set through transfer learning. Furthermore, Gaussian noise (GN)-based analytical models are leveraged to assist in the training of ML-based models for fiber loss and nonlinear impairments. The proposed approach is evaluated under four distinct optical link configurations. On a five-span system comprising six EDFAs, the method achieves a mean absolute error of 0.22 and 0.13 dB for OSNR prediction of background channels and GSNR prediction for 400 GbE channels, respectively.
{"title":"Scalable ML models and cascaded learning for efficient multi-span OSNR and GSNR prediction","authors":"Zehao Wang;Andrea D'Amico;Giacomo Borraccini;Agastya Raj;Yue-Kai Huang;Shaobo Han;Ting Wang;Marco Ruffini;Dan Kilper;Tingjun Chen","doi":"10.1364/JOCN.572370","DOIUrl":"https://doi.org/10.1364/JOCN.572370","url":null,"abstract":"Scalable and efficient methods for predicting optical transmission performance using machine learning (ML) and cascaded learning (CL) are investigated in metro multi-span optical networks. We extend the CL framework beyond multi-span power spectrum prediction to enable accurate estimation of optical signal-to-noise (OSNR) and generalized signal-to-noise (GSNR) under dynamic channel loading, integrating cascaded component models for end-to-end (E2E) optical link performance prediction. To mitigate error accumulation inherent in cascaded predictions, additional E2E optical link measurements and models are incorporated. To ensure scalability, component-level models for erbium-doped fiber amplifier (EDFA) gain and noise figure are pre-trained prior to deployment. We demonstrate that the data collection effort for pre-training the EDFA model can be reduced to only 5.5% of the original training set through transfer learning. Furthermore, Gaussian noise (GN)-based analytical models are leveraged to assist in the training of ML-based models for fiber loss and nonlinear impairments. The proposed approach is evaluated under four distinct optical link configurations. On a five-span system comprising six EDFAs, the method achieves a mean absolute error of 0.22 and 0.13 dB for OSNR prediction of background channels and GSNR prediction for 400 GbE channels, respectively.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"18 1","pages":"A88-A99"},"PeriodicalIF":4.3,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830965","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}
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