Quantum key distribution (QKD) can provide long-term security for numerous users. Currently, quantum networks are still in the early stages of small-scale deployment, most of which can only support a single QKD protocol (QKDP). However, with the advancement of various QKDPs, a single-protocol quantum network is no longer sufficient to meet the demands of multiple users, prompting the emergence of multi-protocol quantum networks. Nevertheless, the transition from a single-protocol to a multi-protocol quantum network still faces many challenging issues, such as key negotiation interruptions due to device initialization and channel calibration during protocol updating. To address the quantum key negotiation interruption problem, we propose a seamless key negotiation oriented multi-protocol updating algorithm in this work, which can fulfill the protocol updating requests of different users in quantum metropolitan networks. Furthermore, to better improve network performance while meeting diverse user demands, we propose four heuristic algorithms for optimal QKDP recommendation, focusing on their applications for multi-protocol updating in different types of typical networks. We perform the simulations with different QKDP recommendation algorithms to analyze the impact of the cache time of the key cache area on the key negotiation interruption probability and the time resource utilization. Simulation results demonstrate that the proposed algorithm can reduce the key negotiation interruption probability by 77.7% while increasing the time resource utilization by 15.3% compared to no key cache area.
{"title":"Multi-protocol updating for seamless key negotiation in quantum metropolitan networks","authors":"Jiali Zhu;Yuan Cao;Mingxuan Guo;Xingyu Zhou;Chunhui Zhang;Jian Li;Xiaosong Yu;Yongli Zhao;Jie Zhang;Qin Wang","doi":"10.1364/JOCN.511999","DOIUrl":"https://doi.org/10.1364/JOCN.511999","url":null,"abstract":"Quantum key distribution (QKD) can provide long-term security for numerous users. Currently, quantum networks are still in the early stages of small-scale deployment, most of which can only support a single QKD protocol (QKDP). However, with the advancement of various QKDPs, a single-protocol quantum network is no longer sufficient to meet the demands of multiple users, prompting the emergence of multi-protocol quantum networks. Nevertheless, the transition from a single-protocol to a multi-protocol quantum network still faces many challenging issues, such as key negotiation interruptions due to device initialization and channel calibration during protocol updating. To address the quantum key negotiation interruption problem, we propose a seamless key negotiation oriented multi-protocol updating algorithm in this work, which can fulfill the protocol updating requests of different users in quantum metropolitan networks. Furthermore, to better improve network performance while meeting diverse user demands, we propose four heuristic algorithms for optimal QKDP recommendation, focusing on their applications for multi-protocol updating in different types of typical networks. We perform the simulations with different QKDP recommendation algorithms to analyze the impact of the cache time of the key cache area on the key negotiation interruption probability and the time resource utilization. Simulation results demonstrate that the proposed algorithm can reduce the key negotiation interruption probability by 77.7% while increasing the time resource utilization by 15.3% compared to no key cache area.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 7","pages":"735-749"},"PeriodicalIF":5.0,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141333960","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}
Today, IP-Optical networks apply IP restoration as the default strategy to recover IP traffic from optical failures. This strategy has been preferred over optical restoration as it circumvents the lengthy delays involved in the reconfiguration of the optical layer. Although fast, IP restoration requires the overprovisioning of costly capacity to cope with optical failures. The advent of software-defined optical networking enables a changeover towards more efficient methods that integrate IP-Optical restoration. These methods should not only restore traffic from failures considered in the planning phase, but they should also efficiently restore traffic from unforeseen failures. This paper studies this problem by investigating optimization algorithms for capacity planning and multilayer restoration based on the theory of adjustable robust optimization (ARO). The approach performs offline optimization of the capacities of IP links as well as the routing and capacities of IP tunnels in both failure-free mode of operation and in a foreseen set of optical failures. Besides, the approach optimizes an affine policy that is applied online to recover IP traffic from unforeseen failures, thereby providing robustness to optical failures not regarded in the planning phase. To overcome the limitations of the affine policy, an alternative robust algorithm is formulated based on deep reinforcement learning (DRL) and graph neural networks (GNNs). By training a DRL-GNN agent, the performance of the restoration process is improved by further minimizing the traffic losses when unforeseen optical failures occur. Results in selected scenarios show that the algorithms outperform IP restoration in terms of capacity requirements, while minimizing the traffic losses in the case of failures. Moreover, the DRL-GNN method significantly improves the ARO-based affine algorithm, which shows the capability of learning the complex relationship between the capacity impairments caused by optical failures and the routing strategy required to restore IP traffic.
如今，IP-光网络将 IP 恢复作为从光故障中恢复 IP 流量的默认策略。与光恢复相比，这种策略更受青睐，因为它避免了光层重新配置所带来的长时间延迟。IP 恢复虽然速度快，但需要超额配置昂贵的容量来应对光故障。软件定义光网络的出现，使我们能够转向集成 IP 光恢复功能的更高效方法。这些方法不仅能从规划阶段考虑的故障中恢复流量，还能从不可预见的故障中有效恢复流量。本文以可调整鲁棒优化（ARO）理论为基础，通过研究容量规划和多层恢复的优化算法来研究这一问题。该方法在无故障运行模式和预知光故障情况下，对 IP 链路的容量以及 IP 隧道的路由和容量进行离线优化。此外，该方法还优化了仿射策略，该策略可在线应用，以从不可预见的故障中恢复 IP 流量，从而为规划阶段未考虑到的光故障提供稳健性。为了克服仿射策略的局限性，基于深度强化学习（DRL）和图神经网络（GNN）制定了另一种稳健算法。通过训练 DRL-GNN 代理，可在发生不可预见的光故障时进一步将流量损失降至最低，从而提高恢复过程的性能。选定场景中的结果表明，这些算法在容量要求方面优于 IP 恢复，同时在故障情况下最大限度地减少了流量损失。此外，DRL-GNN 方法显著改进了基于 ARO 的仿射算法，显示了学习光故障造成的容量损害与恢复 IP 流量所需的路由策略之间复杂关系的能力。
{"title":"Multilayer restoration in IP-Optical networks by adjustable robust optimization and deep reinforcement learning","authors":"Malek Bekri;Ronald Romero Reyes;Thomas Bauschert","doi":"10.1364/JOCN.523894","DOIUrl":"10.1364/JOCN.523894","url":null,"abstract":"Today, IP-Optical networks apply IP restoration as the default strategy to recover IP traffic from optical failures. This strategy has been preferred over optical restoration as it circumvents the lengthy delays involved in the reconfiguration of the optical layer. Although fast, IP restoration requires the overprovisioning of costly capacity to cope with optical failures. The advent of software-defined optical networking enables a changeover towards more efficient methods that integrate IP-Optical restoration. These methods should not only restore traffic from failures considered in the planning phase, but they should also efficiently restore traffic from unforeseen failures. This paper studies this problem by investigating optimization algorithms for capacity planning and multilayer restoration based on the theory of adjustable robust optimization (ARO). The approach performs offline optimization of the capacities of IP links as well as the routing and capacities of IP tunnels in both failure-free mode of operation and in a foreseen set of optical failures. Besides, the approach optimizes an affine policy that is applied online to recover IP traffic from unforeseen failures, thereby providing robustness to optical failures not regarded in the planning phase. To overcome the limitations of the affine policy, an alternative robust algorithm is formulated based on deep reinforcement learning (DRL) and graph neural networks (GNNs). By training a DRL-GNN agent, the performance of the restoration process is improved by further minimizing the traffic losses when unforeseen optical failures occur. Results in selected scenarios show that the algorithms outperform IP restoration in terms of capacity requirements, while minimizing the traffic losses in the case of failures. Moreover, the DRL-GNN method significantly improves the ARO-based affine algorithm, which shows the capability of learning the complex relationship between the capacity impairments caused by optical failures and the routing strategy required to restore IP traffic.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 7","pages":"721-734"},"PeriodicalIF":5.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141099619","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}
We propose and demonstrate a novel O-band wavelength division multiplexing (WDM) optical transceiver enabled by the hybrid photonic integration of indium phosphide (InP) components into a polymer-based photonic motherboard called PolyBoard. The optical engine hosts an eight-fold InP electro-absorption modulated laser (EML) array at the transmitter part exhibiting ${gt}{{35}};{rm{GHz}}$ electro-optical bandwidth and an eight-fold InP photodiode (PD) array at the receiver part with 50 GHz bandwidth, butt-end coupled to the PolyBoard motherboard, which accommodates passive arrayed waveguide gratings (AWGs) at the transmitter and receiver sides, responsible for performing the wavelength multiplexing and demultiplexing functionalities, respectively. What we believe to be a novel thin-film-based O-band half-wave plate is placed at the receiver side AWG, ensuring the polarization insensitivity of the prototype. The optical engine’s design is discussed in the manuscript, demonstrating experimental results from its static and dynamic evaluation. Individual characterization of the transmitter and receiver sides of the optical engine is presented before evaluating the optical engine as a whole in a loopback configuration. The obtained results underscore the potential of the proposed hybrid photonic integrated transceiver for supporting 800 Gb/s capacity in intra-datacenter optical interconnects for transmission distances up to 2 km.
我们提出并演示了一种新型 O 波段波分复用（WDM）光收发器，该收发器通过将磷化铟（InP）元件混合光子集成到名为 PolyBoard 的聚合物基光子主板中来实现。该光学引擎在发射器部分安装了一个八倍 InP 电吸收调制激光器（EML）阵列，具有 ${gt}{35}}；{rm{GHz}}$电光带宽，接收器部分有一个带宽为50 GHz的八倍InP光电二极管（PD）阵列，对接端耦合到PolyBoard主板上，该主板在发射器和接收器一侧安装了无源阵列波导光栅（AWG），分别负责执行波长复用和解复用功能。我们认为，接收器侧的波导光栅采用了一种基于薄膜的新型 O 波段半波板，确保了原型的偏振不敏感性。手稿中讨论了光学引擎的设计，并展示了其静态和动态评估的实验结果。在对环回配置中的整个光学引擎进行评估之前，先介绍了光学引擎发射端和接收端的单独特性。所获得的结果证明了所提出的混合光子集成收发器在数据中心内部光互连中支持 800 Gb/s 容量的潜力，其传输距离可达 2 千米。
{"title":"Integrated 800 Gb/s O-band WDM optical transceiver enabled by hybrid InP-polymer photonic integration","authors":"Efstathios Andrianopoulos;Konstantinos Tokas;David de Felipe;Michael Theurer;Madeleine Weigel;Annachiara Pagano;Kostantina Kanta;Martin Kresse;Giorgos Megas;Christos Tsokos;Christos Kouloumentas;Anna Chiado Piat;Zerihun Tegegne;Maria Massaouti;Paraskevas Bakopoulos;Martin Moehrle;Patrick Runge;Norbert Keil;Panos Groumas;Hercules Avramopoulos","doi":"10.1364/JOCN.522903","DOIUrl":"10.1364/JOCN.522903","url":null,"abstract":"We propose and demonstrate a novel O-band wavelength division multiplexing (WDM) optical transceiver enabled by the hybrid photonic integration of indium phosphide (InP) components into a polymer-based photonic motherboard called PolyBoard. The optical engine hosts an eight-fold InP electro-absorption modulated laser (EML) array at the transmitter part exhibiting \u0000<tex>${gt}{{35}};{rm{GHz}}$</tex>\u0000 electro-optical bandwidth and an eight-fold InP photodiode (PD) array at the receiver part with 50 GHz bandwidth, butt-end coupled to the PolyBoard motherboard, which accommodates passive arrayed waveguide gratings (AWGs) at the transmitter and receiver sides, responsible for performing the wavelength multiplexing and demultiplexing functionalities, respectively. What we believe to be a novel thin-film-based O-band half-wave plate is placed at the receiver side AWG, ensuring the polarization insensitivity of the prototype. The optical engine’s design is discussed in the manuscript, demonstrating experimental results from its static and dynamic evaluation. Individual characterization of the transmitter and receiver sides of the optical engine is presented before evaluating the optical engine as a whole in a loopback configuration. The obtained results underscore the potential of the proposed hybrid photonic integrated transceiver for supporting 800 Gb/s capacity in intra-datacenter optical interconnects for transmission distances up to 2 km.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 8","pages":"D44-D52"},"PeriodicalIF":5.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141103051","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}
Sergio Hernandez;Christophe Peucheret;Francesco Da Ros;Darko Zibar
The use of directly modulated lasers (DMLs) is attractive in low-power, cost-constrained short-reach optical links. However, their limited modulation bandwidth can induce waveform distortion, undermining their data throughput. Traditional distortion mitigation techniques have relied mainly on the separate training of transmitter-side pre-distortion and receiver-side equalization. This approach overlooks the potential gains obtained by simultaneous optimization of the transmitter (constellation and pulse shaping) and receiver (equalization and symbol demapping). Moreover, in the context of DML operation, the choice of laser-driving configuration parameters such as the bias current and peak-to-peak modulation current has a significant impact on system performance. We propose, to our knowledge, a novel end-to-end optimization approach for DML systems, incorporating the learning of bias and peak-to-peak modulation current to the optimization of constellation points, pulse shaping, and equalization. The simulation of the DML dynamics is based on the use of the laser rate equations at symbol rates between 15 and 25 Gbaud. The resulting output sequences from the rate equations are used to build a differentiable data-driven model, simplifying the calculation of gradients needed for end-to-end optimization. The proposed end-to-end approach is compared to three additional benchmark approaches: the uncompensated system without equalization, a receiver-side finite impulse response equalization approach, and an end-to-end approach with learnable pulse shape and nonlinear Volterra equalization but fixed bias and peak-to-peak modulation current. The numerical simulations on the four approaches show that the joint optimization of bias, peak-to-peak current, constellation points, pulse shaping, and equalization outperforms all other approaches throughout the tested symbol rates.
{"title":"End-to-end optimization of optical communication systems based on directly modulated lasers","authors":"Sergio Hernandez;Christophe Peucheret;Francesco Da Ros;Darko Zibar","doi":"10.1364/JOCN.522761","DOIUrl":"10.1364/JOCN.522761","url":null,"abstract":"The use of directly modulated lasers (DMLs) is attractive in low-power, cost-constrained short-reach optical links. However, their limited modulation bandwidth can induce waveform distortion, undermining their data throughput. Traditional distortion mitigation techniques have relied mainly on the separate training of transmitter-side pre-distortion and receiver-side equalization. This approach overlooks the potential gains obtained by simultaneous optimization of the transmitter (constellation and pulse shaping) and receiver (equalization and symbol demapping). Moreover, in the context of DML operation, the choice of laser-driving configuration parameters such as the bias current and peak-to-peak modulation current has a significant impact on system performance. We propose, to our knowledge, a novel end-to-end optimization approach for DML systems, incorporating the learning of bias and peak-to-peak modulation current to the optimization of constellation points, pulse shaping, and equalization. The simulation of the DML dynamics is based on the use of the laser rate equations at symbol rates between 15 and 25 Gbaud. The resulting output sequences from the rate equations are used to build a differentiable data-driven model, simplifying the calculation of gradients needed for end-to-end optimization. The proposed end-to-end approach is compared to three additional benchmark approaches: the uncompensated system without equalization, a receiver-side finite impulse response equalization approach, and an end-to-end approach with learnable pulse shape and nonlinear Volterra equalization but fixed bias and peak-to-peak modulation current. The numerical simulations on the four approaches show that the joint optimization of bias, peak-to-peak current, constellation points, pulse shaping, and equalization outperforms all other approaches throughout the tested symbol rates.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 8","pages":"D29-D43"},"PeriodicalIF":5.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141127619","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 computing first network (CFN) supported by the elastic optical network (EON) is proposed as an innovative information infrastructure, where end users can access computing resources on demand. However, since the link capacity is limited, the network capacity bottleneck may cause task offloading failures even with sufficient computing resources. This paper proposes a cost-efficient computing and spectrum resource scheduling scheme to solve the above problem. The goal is to determine offloading decisions for dependent tasks by minimizing the completion delay and the energy consumption on computing nodes powered by non-green energy (i.e., non-green energy consumption). A priority-weight-based computing and spectrum resource scheduling (PW-CSRS) algorithm is proposed, which can sort the execution order of sub-tasks and optimize computing node selection and spectrum allocation. PW-CSRS is compared with three benchmarks in the 52-node and 33-node systems, and simulation results show that PW-CSRS can effectively improve the acceptance ratio and reduce non-green energy consumption.
{"title":"Priority-weight-based computing and spectrum resource scheduling for dependent tasks in EON-supported computing first networks","authors":"Jingjie Xin;Xin Li;Lu Zhang;Yongjun Zhang;Shanguo Huang","doi":"10.1364/JOCN.522386","DOIUrl":"10.1364/JOCN.522386","url":null,"abstract":"The computing first network (CFN) supported by the elastic optical network (EON) is proposed as an innovative information infrastructure, where end users can access computing resources on demand. However, since the link capacity is limited, the network capacity bottleneck may cause task offloading failures even with sufficient computing resources. This paper proposes a cost-efficient computing and spectrum resource scheduling scheme to solve the above problem. The goal is to determine offloading decisions for dependent tasks by minimizing the completion delay and the energy consumption on computing nodes powered by non-green energy (i.e., non-green energy consumption). A priority-weight-based computing and spectrum resource scheduling (PW-CSRS) algorithm is proposed, which can sort the execution order of sub-tasks and optimize computing node selection and spectrum allocation. PW-CSRS is compared with three benchmarks in the 52-node and 33-node systems, and simulation results show that PW-CSRS can effectively improve the acceptance ratio and reduce non-green energy consumption.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 7","pages":"706-720"},"PeriodicalIF":5.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141117000","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}
Data center networks are experiencing unprecedented exponential growth, mostly driven by the continuous computing demands in machine learning and artificial intelligence algorithms. Within this realm, optical networking offers numerous advantages, including low latency, energy efficiency, and bandwidth transparency, positioning it as a compelling alternative to its electronic counterparts. In this work, we showcase a range of software-defined optical networking applications deployed on a general-purpose programmable integrated photonic processor. Leveraging graph-based theory, we experimentally demonstrate dynamic optical interconnects, circuit switching, and multicasting on the same photonic platform, yielding remarkable results in terms of crosstalk and reconfiguration speed. Our approach harnesses the benefits of reconfigurability and reliability, paving the way for a new generation of high-performance optical devices tailored for data center and computing clusters.
{"title":"Software-defined optical networking applications enabled by programmable integrated photonics","authors":"Zhenyun Xie;David Sanchez-Jacome;Luis Torrijos-Moran;Daniel Perez-Lopez","doi":"10.1364/JOCN.521505","DOIUrl":"https://doi.org/10.1364/JOCN.521505","url":null,"abstract":"Data center networks are experiencing unprecedented exponential growth, mostly driven by the continuous computing demands in machine learning and artificial intelligence algorithms. Within this realm, optical networking offers numerous advantages, including low latency, energy efficiency, and bandwidth transparency, positioning it as a compelling alternative to its electronic counterparts. In this work, we showcase a range of software-defined optical networking applications deployed on a general-purpose programmable integrated photonic processor. Leveraging graph-based theory, we experimentally demonstrate dynamic optical interconnects, circuit switching, and multicasting on the same photonic platform, yielding remarkable results in terms of crosstalk and reconfiguration speed. Our approach harnesses the benefits of reconfigurability and reliability, paving the way for a new generation of high-performance optical devices tailored for data center and computing clusters.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 8","pages":"D10-D17"},"PeriodicalIF":5.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141308684","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}
Addressing the capacity, low cost, and low power challenges of 6G distribution networks, this paper proposes and demonstrates a multi-band optical metro-access network architecture employing semiconductor optical amplifier (SOA)-based wavelength division multiplexing (WDM) switches as low-cost and low-power multi-band optical add-drop multiplexers (MB-OADMs) to extend the capacity beyond C-band limits. We implemented and evaluated the performance of an SOA-based MB-OADM prototype in the C- and O-bands including the network reconfigurability, the node scalability, and the capability to support high-capacity transmission. Experimental results show that the MB-OADM-based network maintains high optical signal-to-noise ratio (OSNR) values up to 35.38 dB in the C-band and 33.56 dB in the O-band over 100 km across five nodes with a 20 km linkspan in between (a total of 100 km) without additional optical amplifiers at 25 Gbps. This work also assesses the MB-OADM-based network scalability in terms of nodes and data rate. Results indicated that the architecture supports cascading through nine C-band nodes over 45 km with a 3.6 dB power penalty at 25 Gbps for a bit error rate (BER) of ${{10}^{- 6}}$ and through four O-band nodes with a 3 dB penalty at 25 Gbps for a BER of ${{10}^{- 6}}$ , maintaining nearly uniform power levels across channels at a BER under the FEC threshold. It successfully demonstrates PAM-4 at 50 Gbps and 100 Gbps data rate transmission operation crossing four nodes over a 4 km distance, with 2 dB and 2.4 dB power penalty at a BER of ${{10}^{- 3}}$ in the C-band and 1.85 dB and 2.2 dB power penalty at a BER of ${{10}^{- 3}}$ in the O-band, respectively.
{"title":"Photonic WDM switches architecture for multi-band optical networks","authors":"Shiyi Xia;Zhouyi Hu;Marijn Rombouts;Henrique Freire Santana;Yu Wang;Aref Rasoulzadeh Zali;Oded Raz;Nicola Calabretta","doi":"10.1364/JOCN.522806","DOIUrl":"10.1364/JOCN.522806","url":null,"abstract":"Addressing the capacity, low cost, and low power challenges of 6G distribution networks, this paper proposes and demonstrates a multi-band optical metro-access network architecture employing semiconductor optical amplifier (SOA)-based wavelength division multiplexing (WDM) switches as low-cost and low-power multi-band optical add-drop multiplexers (MB-OADMs) to extend the capacity beyond C-band limits. We implemented and evaluated the performance of an SOA-based MB-OADM prototype in the C- and O-bands including the network reconfigurability, the node scalability, and the capability to support high-capacity transmission. Experimental results show that the MB-OADM-based network maintains high optical signal-to-noise ratio (OSNR) values up to 35.38 dB in the C-band and 33.56 dB in the O-band over 100 km across five nodes with a 20 km linkspan in between (a total of 100 km) without additional optical amplifiers at 25 Gbps. This work also assesses the MB-OADM-based network scalability in terms of nodes and data rate. Results indicated that the architecture supports cascading through nine C-band nodes over 45 km with a 3.6 dB power penalty at 25 Gbps for a bit error rate (BER) of \u0000<tex>${{10}^{- 6}}$</tex>\u0000 and through four O-band nodes with a 3 dB penalty at 25 Gbps for a BER of \u0000<tex>${{10}^{- 6}}$</tex>\u0000, maintaining nearly uniform power levels across channels at a BER under the FEC threshold. It successfully demonstrates PAM-4 at 50 Gbps and 100 Gbps data rate transmission operation crossing four nodes over a 4 km distance, with 2 dB and 2.4 dB power penalty at a BER of \u0000<tex>${{10}^{- 3}}$</tex>\u0000 in the C-band and 1.85 dB and 2.2 dB power penalty at a BER of \u0000<tex>${{10}^{- 3}}$</tex>\u0000 in the O-band, respectively.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 8","pages":"D18-D28"},"PeriodicalIF":5.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116733","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}
Doutje van Veen;Amitkumar Mahadevan;Michael Straub;Robert Borkowski;Rene Bonk;Vincent Houtsma
Due to continuously emerging high bandwidth applications, research and standardization of time division multiplexed passive optical networks (TDM-PONs) have focused on increasing the peak bitrate. However, increasing the bitrate while supporting the stringent optical power budget of a PON becomes increasingly challenging because of the larger chromatic dispersion penalties as well as reduced receiver sensitivity when the bitrate of the intensity modulation with direct-detection (IM-DD) based PON is increased. Also, increasing bitrate generally causes higher power consumption, which leads to more challenging thermal designs and misalignment with environmental targets. In this paper we give an overview of flexible concepts that can help achieve the required optical power budget and support reduced power consumption of a future IM-DD based TDM-PON. We demonstrate that a flexible PON can provide an increased overall throughput or an extended reach and power budget with the use of flexible modulation formats, probabilistic and geometric shaping, and flexible rate forward error correction (FEC). Another dimension of flexibility in the form of a configurable optical distribution network (ODN) is described and its merits and challenges are discussed. Flexible concepts based on interleaving of FEC codewords can align signal processing like FEC decoding and the protocol processing closer to the user-rate of an optical network unit (ONU), which leads to reduced power consumption. Flexibility based on multiple channels based on wavelength multiplexing or spatial multiplexing enables optimization of the power consumption to the amount of traffic on the PON. Several flexible concepts have already been adopted in the PON standards. We highlight flexible gain FEC for upstream 50G PON, the transmitter dispersion eye closure (TDEC) metric, and the flexible split-ratio ODN for power saving. Flexible modulation has not been adopted yet in PON standards, but it is expected that flexibility is more and more needed to support the performance, cost effectiveness, and power conservation of future optical access systems.
{"title":"Benefits of flexibility in current and future IM-DD based TDM-PON [Invited]","authors":"Doutje van Veen;Amitkumar Mahadevan;Michael Straub;Robert Borkowski;Rene Bonk;Vincent Houtsma","doi":"10.1364/JOCN.517487","DOIUrl":"10.1364/JOCN.517487","url":null,"abstract":"Due to continuously emerging high bandwidth applications, research and standardization of time division multiplexed passive optical networks (TDM-PONs) have focused on increasing the peak bitrate. However, increasing the bitrate while supporting the stringent optical power budget of a PON becomes increasingly challenging because of the larger chromatic dispersion penalties as well as reduced receiver sensitivity when the bitrate of the intensity modulation with direct-detection (IM-DD) based PON is increased. Also, increasing bitrate generally causes higher power consumption, which leads to more challenging thermal designs and misalignment with environmental targets. In this paper we give an overview of flexible concepts that can help achieve the required optical power budget and support reduced power consumption of a future IM-DD based TDM-PON. We demonstrate that a flexible PON can provide an increased overall throughput or an extended reach and power budget with the use of flexible modulation formats, probabilistic and geometric shaping, and flexible rate forward error correction (FEC). Another dimension of flexibility in the form of a configurable optical distribution network (ODN) is described and its merits and challenges are discussed. Flexible concepts based on interleaving of FEC codewords can align signal processing like FEC decoding and the protocol processing closer to the user-rate of an optical network unit (ONU), which leads to reduced power consumption. Flexibility based on multiple channels based on wavelength multiplexing or spatial multiplexing enables optimization of the power consumption to the amount of traffic on the PON. Several flexible concepts have already been adopted in the PON standards. We highlight flexible gain FEC for upstream 50G PON, the transmitter dispersion eye closure (TDEC) metric, and the flexible split-ratio ODN for power saving. Flexible modulation has not been adopted yet in PON standards, but it is expected that flexibility is more and more needed to support the performance, cost effectiveness, and power conservation of future optical access systems.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 7","pages":"C113-C120"},"PeriodicalIF":5.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118122","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}
J. Bohata;M. Botella-Campos;J. Mora;B. Ortega;S. Zvanovec
We experimentally demonstrate a photonic full-duplex seamless millimeter wave fronthaul link, based on phase modulation, to address the challenges arising from the increased demands on the mobile fronthaul capacity and network densification toward 5G and beyond. The proposed system relies on phase modulation techniques, implemented at both the central office (CO) and remote radio head (RRH), to achieve optical frequency up-conversion of the downlink (DL) signal and optical modulation of the down-converted uplink (UL) signal. Furthermore, our approach includes the frequency down-conversion of the 40 GHz UL signal through an optically generated local oscillator (LO) signal in the RRH, while the laser employed for UL data transmission is situated at the CO, simplifying the remote site’s equipment. An optical waveshaper serves here as a programmable optical filter to provide signals for DL frequency up-conversion, LO generation, and also the optical carrier for UL transmission. In our experimental validation, we have tested our proposed system using 64-quadrature amplitude modulation (64-QAM) for the DL at a frequency of 41 GHz and quadrature phase shift keying (QPSK) for the UL at a frequency of 40 GHz. Notably, our results demonstrate the successful transmission of up to 200 MHz bandwidth for both digital modulation schemes, all while maintaining the error vector magnitude (EVM) well below the specified threshold. Additionally, when employing 5G new radio (NR) orthogonal frequency-division multiplexing (OFDM) signals with the same modulation formats for both links in full-duplex communication, we achieved EVM values as low as 5.2% for the DL and 6.9% for the UL, further highlighting the efficacy and robustness of our proposed solution.
{"title":"Centralized full-duplex seamless photonic mmW fronthaul link based on phase modulation","authors":"J. Bohata;M. Botella-Campos;J. Mora;B. Ortega;S. Zvanovec","doi":"10.1364/JOCN.514977","DOIUrl":"10.1364/JOCN.514977","url":null,"abstract":"We experimentally demonstrate a photonic full-duplex seamless millimeter wave fronthaul link, based on phase modulation, to address the challenges arising from the increased demands on the mobile fronthaul capacity and network densification toward 5G and beyond. The proposed system relies on phase modulation techniques, implemented at both the central office (CO) and remote radio head (RRH), to achieve optical frequency up-conversion of the downlink (DL) signal and optical modulation of the down-converted uplink (UL) signal. Furthermore, our approach includes the frequency down-conversion of the 40 GHz UL signal through an optically generated local oscillator (LO) signal in the RRH, while the laser employed for UL data transmission is situated at the CO, simplifying the remote site’s equipment. An optical waveshaper serves here as a programmable optical filter to provide signals for DL frequency up-conversion, LO generation, and also the optical carrier for UL transmission. In our experimental validation, we have tested our proposed system using 64-quadrature amplitude modulation (64-QAM) for the DL at a frequency of 41 GHz and quadrature phase shift keying (QPSK) for the UL at a frequency of 40 GHz. Notably, our results demonstrate the successful transmission of up to 200 MHz bandwidth for both digital modulation schemes, all while maintaining the error vector magnitude (EVM) well below the specified threshold. Additionally, when employing 5G new radio (NR) orthogonal frequency-division multiplexing (OFDM) signals with the same modulation formats for both links in full-duplex communication, we achieved EVM values as low as 5.2% for the DL and 6.9% for the UL, further highlighting the efficacy and robustness of our proposed solution.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 6","pages":"670-680"},"PeriodicalIF":5.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140984623","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 efficiency of optical networks employing flexible wavelength division multiplexing (WDM) can be increased by maximizing the throughput of each individual channel, provided that the position of its neighboring channel is known with sufficient accuracy in order to avoid inter-channel interference. In this paper, we propose a digital signal processing (DSP) algorithm, leveraging the use of an artificial neural network (ANN), to estimate the neighboring channels’ distance by processing raw digital samples from a standard coherent receiver. We present an efficient dataset design approach, based on Latin hypercube sampling (LHS), in order to effectively optimize and validate the algorithm under different assumptions on the optical WDM channels. We investigate the accuracy of the ANN-based DSP scheme through simulation analysis, highlighting its potential in relation to the characteristics of the optical network. Finally, we validate our approach in an experimental setup using standard commercial coherent transceivers. The experimental results show that the distance from the neighboring WDM channels can be estimated with a root mean square error of less than 1.5 GHz for a channel under test with a symbol rate of 52 GBaud.
采用灵活波分复用（WDM）技术的光网络可以通过最大限度地提高单个信道的吞吐量来提高效率，但前提是必须足够准确地知道相邻信道的位置，以避免信道间干扰。在本文中，我们提出了一种数字信号处理（DSP）算法，利用人工神经网络（ANN），通过处理来自标准相干接收器的原始数字样本来估计相邻信道的距离。我们提出了一种基于拉丁超立方采样（LHS）的高效数据集设计方法，以便在光波分复用信道的不同假设条件下有效优化和验证算法。我们通过仿真分析研究了基于 ANN 的 DSP 方案的准确性，强调了其与光网络特性相关的潜力。最后，我们在使用标准商用相干收发器的实验装置中验证了我们的方法。实验结果表明，对于符号率为 52 GBaud 的被测信道，相邻波分复用信道的距离估计均方根误差小于 1.5 GHz。
{"title":"DSP-based inter-channel interference monitoring in flexible wavelength-routed networks","authors":"Leonardo Minelli;Gabriella Bosco;Stefano Straullu;Antonino Nespola;Stefano Piciaccia;Dario Pilori","doi":"10.1364/JOCN.523440","DOIUrl":"10.1364/JOCN.523440","url":null,"abstract":"The efficiency of optical networks employing flexible wavelength division multiplexing (WDM) can be increased by maximizing the throughput of each individual channel, provided that the position of its neighboring channel is known with sufficient accuracy in order to avoid inter-channel interference. In this paper, we propose a digital signal processing (DSP) algorithm, leveraging the use of an artificial neural network (ANN), to estimate the neighboring channels’ distance by processing raw digital samples from a standard coherent receiver. We present an efficient dataset design approach, based on Latin hypercube sampling (LHS), in order to effectively optimize and validate the algorithm under different assumptions on the optical WDM channels. We investigate the accuracy of the ANN-based DSP scheme through simulation analysis, highlighting its potential in relation to the characteristics of the optical network. Finally, we validate our approach in an experimental setup using standard commercial coherent transceivers. The experimental results show that the distance from the neighboring WDM channels can be estimated with a root mean square error of less than 1.5 GHz for a channel under test with a symbol rate of 52 GBaud.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"16 6","pages":"695-705"},"PeriodicalIF":5.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140978768","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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