Article
Engineering, Electrical & Electronic
Tetsuya Hayashi, Taiji Sakamoto, Yusuke Yamada, Roland Ryf, Rene-Jean Essiambre, Nicolas Fontaine, Mikael Mazur, Haoshuo Chen, Takemi Hasegawa
Summary: Randomly-coupled multi-core fiber (MCF) technology has gained attention for its applicability in long-haul transmission systems. Compared to weakly-coupled MCFs, randomly-coupled MCFs can achieve higher spatial channel density and lower transmission loss using existing single-mode fiber core designs. This article provides an overview of the advancements in randomly-coupled MCF technology, including its classification, design, optical property characterization methods, and performance improvements in transmissions.
PROCEEDINGS OF THE IEEE
(2022)
Article
Engineering, Electrical & Electronic
Georg Rademacher, Ruben S. Luis, Benjamin J. Puttnam, Roland Ryf, Sjoerd van der Heide, Tobias A. Eriksson, Nicolas K. Fontaine, Haoshuo Chen, Rene-Jean Essiambre, Yoshinari Awaji, Hideaki Furukawa, Naoya Wada
Summary: The study explores high-capacity, long-haul transmission over a coupled-core three-core multi-core fiber through experiments. Key system characteristics, optimum launch power, wavelength dependence, and distance-evolution of mode-dependent loss were reported. High data-rate transmission demonstrations with over 75 nm optical bandwidth were achieved, showcasing the potential of using coupled-core multi-core fibers for wideband optical signals over long distances.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Manabu Arikawa, Mingqi Wu, Keisuke Yasuhara, Daishi Masuda, Kazunori Hayashi, Takanori Inoue, Yoshihisa Inada
Summary: We conducted long-haul transmissions over coupled four-core fibers in a 15-km-long submarine cable, achieving small propagation loss and spatial-mode dispersion. Using adaptive multi-layer filters, we obtained error-free transmission up to 6000 km with 16-channel wavelength-division multiplexed and 4-core space-division multiplexed signals. We also evaluated transmission performance and mode dependent loss, and found that further suppression of MDL is necessary for longer distances and more stable performance.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Yusuke Sasaki, Ryohei Fukumoto, Katsuhiro Takenaga, Shogo Shimizu, Kazuhiko Aikawa
Summary: Combining small-diameter optical-fiber technology with multicore fiber is a promising method to increase the transmission capacity of optical networks. In this study, a four-core fiber with a 200-mu m coating diameter was successfully fabricated and demonstrated excellent performance. It is suitable for applications in high-fiber-count cables.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Georg Rademacher, Ruben S. Luis, Benjamin J. Puttnam, Roland Ryf, Sjoerd van der Heide, Tobias A. Eriksson, Nicolas K. Fontaine, Haoshuo Chen, Rene-Jean Essiambre, Yoshinari Awaji, Hideaki Furukawa
Summary: This paper compares the use of 3-mode few-mode fibers and 3-core coupled-core multi-core fibers in space-division multiplexed transmission systems. The analysis shows that the coupled-core multi-core fiber achieves higher data rates at shorter transmission distances.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Shoma Tateno, Hitoshi Takeshita, Kohei Hosokawa, Emmanuel Le Taillandier de Gabory
Summary: Bidirectional transmission in multicore fiber reduces core-to-core crosstalk, changing the design of multicore fiber and submarine cable systems. By analyzing submarine systems, we demonstrate the capacity increase with bidirectional transmission. For regional Asian systems up to 3,000 km, 6-core MCF systems with bidirectional transmission offer the highest cable capacity.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Cristian Antonelli, Antonio Mecozzi
Summary: The proposed design for coupled-core multi-core fibers aims to achieve extremely low levels of modal dispersion – coined as NEMO fibers. This design sacrifices some fiber mode-mixing effectiveness in exchange for reducing nonlinear signal distortions. A semi-analytical tool developed in this study effectively characterizes the impact of various perturbations on the ideal fiber structure.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Manabu Arikawa, Kohei Nakamura, Kohei Hosokawa, Kazunori Hayashi
Summary: We demonstrated a successful long-haul WDM and SDM transmission of 32-Gbaud polarization-division multiplexed quadrature phase-shift keying signals. Our experiment showed that the mode dependent loss (MDL) of the coupled-4-core EDFAs was a major limiting factor for transmission performance, and the rms MDL per span should be below 0.4 dB for further long-haul transmission distance over 6000 km.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Daiki Soma, Shohei Beppu, Yuta Wakayama, Seiya Sumita, Hidenori Takahashi, Noboru Yoshikane, Itsuro Morita, Takehiro Tsuritani, Masatoshi Suzuki
Summary: The transmission capacity of optical submarine cable systems needs to be continuously increased, with research suggesting that single-band transmission systems with more fiber pairs could be a promising technology. Utilizing space-division multiplexing technologies such as multi-core fibers may offer solutions for further increasing transmission capacity.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Computer Science, Information Systems
Miaofang Zhou, Ping Jiang, Huajun Yang, Weinan Caiyang, Yan Qin, Yifan Zheng
Summary: This paper proposes a new type of optical fiber structure with air trenches, air holes, and a depressed step-index core for efficient mode separation. Simulation results show that the fiber can support up to 12 spatial modes with broadband characteristics.
Article
Engineering, Electrical & Electronic
Yingning Wang, Yuanpeng Liu, Wenqian Zhao, Jian Yang, Wenpu Geng, Yuxi Fang, Changjing Bao, Yongxiong Ren, Zhi Wang, Yan-ge Liu, Zhongqi Pan, Yang Yue
Summary: This paper designs and analyzes a multi-ring-air-core fiber supporting thousands of OAM modes, and investigates the tradeoffs between ring number/density and system performance parameters. Based on the analytical results, the fiber has high transmission rate and spectrum efficiency, and shows great potential for various applications in optical communication systems.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Mark Shtaif, Cristian Antonelli, Antonio Mecozzi, Xi Chen
Summary: This article reviews the challenges faced by optical fiber transmission, discusses the impact of the nonlinear nature of fiber-optic transmission on capacity assessment and fundamental concepts, and introduces some solutions and new transmission schemes. State-of-the-art transmission experiments are also reviewed and compared.
PROCEEDINGS OF THE IEEE
(2022)
Article
Engineering, Electrical & Electronic
Benjamin J. Puttnam, Ruben S. Luis, Georg Rademacher, Yoshinari Awaji, Hideaki Furukawa
Summary: By investigating the recirculating transmission of a wideband S-, C-, and L-band signal in a 4-core fiber, we have discovered the potential to increase data-rates in long-haul optical fiber transmission, including the S-band. Additionally, our experiment confirms that 125 mu m diameter multi-core fibers can multiply transmission capacity and offer the benefits of resource sharing and integration.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Computer Science, Information Systems
Xiaosong Yu, Shufeng Li, Yongli Zhao, Yuan Cao, Avishek Nag, Jie Zhang
Summary: This study introduces four RCWA algorithms for quantum and classical service requests in multi-core optical networks, each with different functions. Simulation results demonstrate that the RCWA-SP algorithm can improve network performance and reduce blocking probability, while the RCWA-XTP algorithm can reduce inter-core crosstalk.
Article
Engineering, Electrical & Electronic
Takashi Matsui, Peter L. Pondillo, Kazuhide Nakajima
Summary: This article discusses the progress and standardization activities of MCF technology in SDM technology and explores the possibilities and availability of MCF technology in practical applications. The article also introduces the progress in establishing international standards for SDM technology and provides a summary of the future development of MCF technology.
PROCEEDINGS OF THE IEEE
(2022)
Article
Engineering, Electrical & Electronic
Georg Rademacher, Benjamin J. Puttnam, Ruben S. Luis, Jun Sakaguchi, Werner Klaus, Tobias A. Eriksson, Yoshinari Awaji, Tetsuya Hayashi, Takuji Nagashima, Tetsuya Nakanishi, Toshiki Taru, Taketoshi Takahata, Tetsuya Kobayashi, Hideaki Furukawa, Naoya Wada
Summary: This study demonstrated high capacity transmission in a multi-core fiber, achieving data rates over 10.66 Pb/s with single optical comb source. It highlighted the impact of mode-dependent loss on achievable data rates within cores, while also exploring the potential for multi-span transmission over the same fiber with performance penalties due to sub-optimal transmission components.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Optics
Tetsu Morishima, Ken Manabe, Shuhei Toyokawa, Tetsuya Nakanishi, Tomomi Sano, Tetsuya Hayashi
Summary: The novel single-MCF connector achieves rotational fiber alignment and ferrule floating by using standard MU ferrule and modified LC housing. Connectors with an average loss of 0.07 dB passed tests, with numerical simulations confirming suppression of ferrule rotation from external forces.
Article
Optics
Davide Bacco, Nicola Biagi, Ilaria Vagniluca, Tetsuya Hayashi, Antonio Mecozzi, Cristian Antonelli, Leif K. Oxenlowe, Alessandro Zavatta
Summary: Multicore fibers are expected to revolutionize optical communications with their larger transmission bandwidth and smaller footprint. Although recent research has explored their use in quantum communication, the feasibility of using long-distance multicore fibers for quantum applications still needs to be proven.
PHOTONICS RESEARCH
(2021)
Article
Optics
Tetsuya Hayashi
Summary: The use of bidirectional multi-core fiber (MCF) transmissions suppresses inter-core crosstalk and improves signal quality and/or core density compared to unidirectional transmissions. This paper derives approximate expressions for Rayleigh backscattered inter-core crosstalk and discusses their accuracy.
Article
Computer Science, Hardware & Architecture
Ruben S. Luis, Benjamin J. Puttnam, Georg Rademacher, Satoshi Shinada, Tetsuya Hayashi, Tetsuya Nakanishi, Yuki Saito, Tetsu Morishima, Hideaki Furukawa
Summary: This study demonstrates the use of spatial division multiplexing (SDM) to implement spine-leaf datacenter network topologies. Two possible scenarios are considered. The first scenario utilizes high-capacity multicore fiber interconnects, achieving a combined throughput of 12.8 Tb/s. The second scenario utilizes multicore fiber interconnects to establish multiple connections between pairs of spin-leaf switches, reducing the number of cables required.
JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING
(2023)
Article
Optics
Yuto Kobayashi, Tetsuya Hayashi
Summary: We quantitatively discuss the impact of core-dependent loss (CDL) on multicore fiber (MCF) crosstalk (XT). Within practical ranges of XT and CDL, CDL does not significantly affect power coupling coefficients and XT between cores. Therefore, considering the CDL-induced signal attenuation difference among cores is sufficient when evaluating the signal-to-XT ratio in MCFs with CDL. We also analyze the effects of CDL on XT measurements and find that the CDLs induced in an MCF as a measurement target and a measurement setup can be canceled by switching the source and destination cores of the XT, using the geometric mean of linear values or arithmetic mean of decibel values.
Article
Engineering, Electrical & Electronic
Tetsuya Hayashi, Taiji Sakamoto, Yusuke Yamada, Roland Ryf, Rene-Jean Essiambre, Nicolas Fontaine, Mikael Mazur, Haoshuo Chen, Takemi Hasegawa
Summary: Randomly-coupled multi-core fiber (MCF) technology has gained attention for its applicability in long-haul transmission systems. Compared to weakly-coupled MCFs, randomly-coupled MCFs can achieve higher spatial channel density and lower transmission loss using existing single-mode fiber core designs. This article provides an overview of the advancements in randomly-coupled MCF technology, including its classification, design, optical property characterization methods, and performance improvements in transmissions.
PROCEEDINGS OF THE IEEE
(2022)
Proceedings Paper
Optics
Masato Yoshida, Toshihiko Hirooka, Nakazawa Masataka, Tetsuya Hayashi, Takemi Hasegawa, Kohei Nakamura, Takanori Inoue
Summary: This paper presents a method for precise distributed measurement of mode-coupling using a multi-channel OTDR on a 60 km long 4-core fiber (4CF) for submarine transmission. By evaluating the crosstalk values separately in the fan-in/out devices and 4CF with a dynamic range of up to 85 dB, the effectiveness of the method is demonstrated.
2022 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)
(2022)
Proceedings Paper
Computer Science, Hardware & Architecture
Luis Felipe Florenzan Reyes, Francesco Smarral, Roland Ryf, Tetsuya Hayashi, Andrea Marotta, Cristian Antonelli, Alessandro D'Innocenzo
Summary: This paper discusses the use of data-driven methodologies to improve the performance of crosstalk cancelation in optical systems supporting multiple spatial modes. It proposes a reduction algorithm based on PCA and cross-correlation analysis to enhance the traditional equalizers' performance. Experimental validation is conducted over the world-first SDM field trial.
2022 31ST INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS (ICCCN 2022)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Tetsuya Hayashi, Takuji Nagashima, Ayumi Inoue, Hirotaka Sakuma, Takahiro Suganuma, Takemi Hasegawa
Summary: This article reviews and discusses the design factors and considerations of MCFs for bidirectional transmissions, including connection polarity and crosstalk requirements, and introduces MCFs suitable for bidirectional long-haul and short-reach transmissions.
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Mikael Mazur, Lauren Dallachiesa, Nicolas K. Fontaine, Roland Ryf, Erik Borjeson, Haoshuo Chen, Hirotaka Sakuma, Takafumi Ohtsuka, Tetsuya Hayashi, Takemi Hasegawa, Hidehisa Tazawa, David T. Neilson, Per Larsson-Edefors
Summary: We have conducted the first transmission experiment using a 7-core coupled-core fiber and in-line coupled-core multi-core amplifiers, and implemented real-time DSP with a single FPGA for MIMO processing across all 7 cores.
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Mikael Mazur, Nicolas K. Fontaine, Steve Corteselli, Haoshuo Chen, Lauren Dallachiesa, Tetsuya Hayashi, Hirotaka Sakuma, Takemi Hasegawa, Roland Ryf, David T. Neilson
Summary: In this study, dual-comb spectroscopy was used to compare the stability and wavelength dependence of mode coupling in a 110 km coupled multi-core fiber and a regular single-mode fiber, revealing differences in coupling dynamics.
2022 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC)
(2022)
Proceedings Paper
Computer Science, Information Systems
Ekaterina Deriushkina, Israel Rebolledo Salgado, Mikael Mazur, Victor Torres-Company, Peter Andrekson, Simon Gross, Michael J. Withford, Tetsuya Hayashi, Takuji Nagashima, Jochen Schroder, Magnus Karlsson
Summary: In this study, a novel method combining swept-wavelength interferometry and dual-comb spectroscopy was employed to measure the transfer matrix of a coupled three-core fiber. The technique achieved a high frequency resolution of 50 kHz while measuring a bandwidth of 1 THz, with just a 25 GHz laser sweep.
2021 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)
(2021)
Proceedings Paper
Computer Science, Information Systems
Mikael Mazur, Nicolas K. Fontaine, Roland Ryf, Haoshuo Chen, Lauren Dallachiesa, Takafumi Ohtsuka, Hirotaka Sakuma, Tetsuya Hayashi, Takemi Hasegawa, Hidehisa Tazawa, David T. Neilson
Summary: This study presents the full transfer matrix characterization of a packaged 7-core coupled-core amplifier, achieving a small mode-dependent loss through pump current optimization. The observed loss is about 3 dB over a gain range of 17 to 25 dB.
2021 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Ruben S. Luis, Benjamin J. Puttnam, Georg Rademacher, Andrea Marotta, Cristian Antonelli, Fabio Graziosi, Antonio Mecozzi, Tetsuya Hayashi, Tetsuya Nakanishi, Satoshi Shinada, Yoshinari Awaji, Hideaki Furukawa, Naoya Wada
Summary: This study reviews recent works analyzing inter-core skew in multi-core fibers, comparing the behaviors of spooled fibers in laboratory conditions with field deployed fibers.
2021 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC)
(2021)