MIMO-less Space Division Multiplexing with Elliptical Core Optical Fibers

Milione, Giovanni; Ip, Ezra; Ji, Philip N.; Huang, Yue-Kai; Wang, Ting; Li, Ming-Jung; Stone, Jeffery S.; Peng, Gaozhu

doi:10.1364/ofc.2017.tu2j.1

Cited by 18 publications

(10 citation statements)

References 9 publications

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“…Even if the eigenmodes are selectively excited at the input end, coupling may occur as in single-mode MCFs when the propagation distance is long. In the case of short-distance propagation, however, the crosstalk may be sufficiently reduced, and a MIMO-free MDM transmission may be possible without using largely deformed elliptical core fibers [52,53,54,55].…”

Section: Discussionmentioning

confidence: 99%

“…However, we could not conclude the cause of the LP 11 mode becoming the eigenmode in this FMF. Anyway, although intentional LP mode transmission has been realized using extremely elliptical deformed core fibers [52,53,54,55,56], we discovered a new phenomenon that the LP modes propagate as the eigenmodes in a few-mode MCF with a small ellipticity [49]. This is an unpredictable phenomenon that contradicts the conventional theory [25,26].…”

Section: Four-lp-mode 12-core Fibermentioning

confidence: 92%

See 1 more Smart Citation

Predictable and unpredictable phenomena in optical fibers for space-division/mode-division multiplexing transmission: statistical analysis of coupling and mysterious behavior of modes

Kimura

Koshiba

2020

IEICE Electron. Express

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The transmission capacity of single-mode single-core fibers is approaching the limit of about 100 Tbps owing to nonlinearity and the fiber fuse, which limit the input signal power. To avoid the so-called capacity crunch and dramatically increase the transmission capacity, a new approach utilizing space-division multiplexing (SDM) and mode-division multiplexing (MDM) has been proposed and demonstrated. In these new multiplexing technologies, a problem that is unprecedented in conventional single-mode fibers, namely, the crosstalk between transmission channels, arises. Although the input signal channels are mixed through at the output end, the signal channel can be identified using multiple-input multipleoutput (MIMO) signal processing technology at the output end. However, even using the MIMO digital signal processing technology, the problem that the computation time increases with the number of channels remains, resulting in increased latency, and so the number of channels is limited. To design a transmission system using the SDM and MDM technologies, the crosstalk should be analyzed precisely. However, the origin and behavior of crosstalk are different in SDM using multicore fibers (MCFs) and in MDM using few-mode fibers (FMFs). The behavior of crosstalk in single-mode MCFs is predictable to some extent by statistical analysis, and the system can be designed by considering the results of the analysis. On the other hand, the behavior of crosstalk of FMFs is less predictable. Since the mode launched at the input end is not the eigenmode, mode discrimination or accurate mode demultiplexing is difficult using a conventional mode demultiplexer. In addition, the eigenmode itself of FMFs is not always the hybrid mode predicted by the conventional theory but sometimes a linearly polarized (LP) mode, contradicting the conventional theory. In other words, the demultiplexed signal always involves crosstalk regardless of the transmission distance, and the quantity of crosstalk cannot be analyzed statistically. Therefore, the crosstalk and its behavior are unpredictable. In spite of these unpredictable phenomena, the signal channel can be identified using the MIMO signal processing as in single-mode MCFs. This means that the MDM technology using FMFs is established in the engineering or inductive logic sense, but still involves unexplained phenomena in the scientific or deductive logic sense. In this review, we discuss the predictable behavior of crosstalk in single-mode MCFs and also the unpredictable behavior of crosstalk in FMFs.

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Section: Discussionmentioning

confidence: 99%

Section: Four-lp-mode 12-core Fibermentioning

confidence: 92%

Predictable and unpredictable phenomena in optical fibers for space-division/mode-division multiplexing transmission: statistical analysis of coupling and mysterious behavior of modes

Kimura

Koshiba

2020

IEICE Electron. Express

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“…the metro, access, intra-or inter-data-center links, etc. ), weak coupling may be maintained between modes or mode groups (MGs) with differential effective refractive index (Δneff) of ~10 -4 -10 -3 [9], potentially enabling partial-MIMO or MIMO-free schemes that improve system capacity with MIMO complexity [10][11][12][13][14][15][16][17][18][19]. In [10][11][12], weakly-coupled FMF transmission incorporating partial-MIMO processing is proposed, in which low inter-mode or inter-MG coupling is ensured by increasing Δneff, so that only smaller MIMO blocks are required to handle the polarization diversity and mode degeneracy.…”

Section: Introductionmentioning

confidence: 99%

“…However, the low MIMO complexity of such schemes may not be sustainable when higher order modes/MGs are explored, as the number of intra-MG modes increases with the mode/MG order. A MIMO-less approach has also been proposed using an elliptical-core FMF to further eliminate the mode degeneracy [13][14][15]. However, higher ellipticity may cut off the highest-order modes, resulting in a trade-off between the number of guided modes (capacity) and the achievable birefringence (DSP complexity) [16].…”

Section: Introductionmentioning

confidence: 99%

Mode Division Multiplexing Based on Ring Core Optical Fibers

Liu

Zhu

Zhang

et al. 2018

IEEE J. Quantum Electron.

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The unique modal characteristics of ring core fibres potentially enable the implementation of mode-division multiplexing (MDM) schemes that can increase optical data transmission capacity with either low complexity modular multiinput multi-output (MIMO) equalization or no MIMO. This paper attempts to present an comprehensive review of recent research on key aspects of RCF-based MDM transmission. Starting from fundamental fibre modal structures, a theoretical comparison between RCF and conventional step-index and graded-index multi-mode fibres in terms of their MDM capacity and the associated MIMO complexity is given first as the underlining rationale behind RCF-MDM. This is followed by a discussion of RCF design considerations for achieving high mode channel count and low crosstalk performances in either MIMO-free or modular MIMO transmission schemes. The principles and implementations of RCF mode (de-)multiplexing devices are discussed in detail, followed by RCF-based optical amplifiers, culminating in MIMOfree or modular MIMO RCF-MDM data transmission schemes. A discussion on further research directions is also given.

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“…OAM modes and other modes are used for optical communication [5][6][7][8][9][10][11][12][13] . Like other facets of light, OAM modes can be used for remote sensing.…”

mentioning

confidence: 99%