186,904 research outputs found
Nonlinear propagation equations in fibers with multiple modes—Transitions between representation bases
Get PDFThe transverse pattern of the field that propagates in a fiber supporting multiple modes can always be described as a superposition of the patterns of the individual fiber modes. Yet, the use of other bases is often found to be more convenient, with the most famous example being that of linearly polarized modes in weakly guiding fibers. The nonlinear propagation equations contain coefficients that involve overlap integrals between the lateral profiles of multiple propagation modes. A fundamental question that has been raised in this context is whether it is legitimate to compute these coefficients from the overlap integrals between elements of alternative bases for the field representation. In this paper, we show that the answer to this question is positive in the most general sense. This result is significant in the context of space-division multiplexed transmission in multi-mode and multi-core fibers
Handbook of Optical Networks
No full textThis handbook is an authoritative, comprehensive reference on optical networks, the backbone of today’s communication and information society. The book reviews the many underlying technologies that enable the global optical communications infrastructure, but also explains current research trends targeted towards continued capacity scaling and enhanced networking flexibility in support of an unabated traffic growth fueled by ever-emerging new applications.
The book is divided into four parts: Optical Subsystems for Transmission and Switching, Core Networks, Datacenter and Super-Computer Networking, and Optical Access and Wireless Networks.
Each chapter is written by world-renown experts that represent academia, industry, and international government and regulatory agencies. Every chapter provides a complete picture of its field, from entry-level information to a snapshot of the respective state-of-the-art technologies to emerging research trends, providing something useful for the novice who wants to get familiar with the field to the expert who wants to get a concise view of future trends
Random coupling between groups of degenerate fiber modes in mode multiplexed transmission
No full textWe study random coupling induced crosstalk between groups of degenerate modes in spatially multiplexed optical transmission. Our analysis shows that the average crosstalk is primarily determined by the wavenumber mismatch, by the correlation length of the random perturbations, and by the coherence length of the degenerate modes, whereas the effect of a deterministic group velocity difference is negligible. The standard deviation of the crosstalk is shown to be comparable to its average value, implying that crosstalk measurements are inherently noisy
Quantum Limits on the Energy Consumption of Optical Transmission Systems
No full textThe search for schemes that minimize the energy associated with the transmission of information is a longstanding fundamental issue in communication theory. In this paper we extend fundamental limits to the energy consumption per unit of information, as given by Shannon’s theory, to the quantum domain. Unlike previous studies, we address a scenario where the signal may be manipulated in an arbitrary way while propagating from the transmitter to the receiver. This situation characterizes many realistic scenarios, such as multi-span fiber-optic communication systems. We obtain the ultimate quantum limit on the energy consumption in this scenario and propose a simple binary energy modulation scheme that approaches this limit within one order of magnitude for practically relevant values of spectral efficiency. Under the same conditions, the quantum energy consumption limit of the standard optically amplified coherent communication scheme is three orders of magnitude above the ultimate identified limit. Throughout the paper we consider transmission of classical information over a quantum channel
Stokes-space analysis of modal dispersion in fibers with multiple mode transmission
No full textModal dispersion (MD) in a multimode fiber may be considered as a generalized form of polarization mode dispersion (PMD) in single mode fibers. Using this analogy, we extend the formalism developed for PMD to characterize MD in fibers with multiple spatial modes. We introduce a MD vector defined in a D-dimensional extended Stokes space whose square length is the sum of the square group delays of the generalized principal states. For strong mode coupling, the MD vector undertakes a D-dimensional isotropic random walk, so that the distribution of its length is a chi distribution with D degrees of freedom. We also characterize the largest differential group delay, that is the difference between the delays of the fastest and the slowest principal states, and show that it too is very well approximated by a chi distribution, although in general with a smaller number of degrees of freedom. Finally, we study the spectral properties of MD in terms of the frequency autocorrelation functions of the MD vector, of the square modulus of the MD vector, and of the largest differential group delay. The analytical results are supported by extensive numerical simulations
Modeling and performance metrics of MIMO-SDM systems with different amplification schemes in the presence of mode-dependent loss
Get PDFMode-dependent loss (MDL) is a major factor limiting the
achievable information rate in multiple-input multiple-output space-division
multiplexed systems. In this paper we show that its impact on system performance,
which we quantify in terms of the capacity reduction relative
to a reference MDL-free system, may depend strongly on the operation
of the inline optical amplifiers. This dependency is particularly strong
in low mode-count systems. In addition, we discuss ways in which the
signal-to-noise ratio of the MDL-free reference system can be defined
and quantify the differences in the predicted capacity loss. Finally, we
stress the importance of correctly accounting for the effect of MDL on the
accumulation of amplification noise
Approaching fundamental energy consumption limits in optical communications
No full textWe study the fundamental energy consumption of fiber-optic communications links. We show that the quantum limit for the energy efficiency of a multi-span system deploying generalized on-off keying with photon-counting inline regeneration exceeds by orders of magnitude that of state-of-the-art systems employing inline optical amplification
Physical layer security of space-division multiplexed fiber-optic communication systems in the presence of multiple eavesdroppers
No full textCriticality of assumptions in the study of performance degradation caused by mode-dependent loss in SDM systems
No full textMode dependent loss is expected to be a major cause of impairments in SDM systems. We show that the accurate characterization of its impact on system performance depends on the assumptions that are made on how the system is modeled and operated in a very subtle way which has eluded the majority of previous studies
An error probability approach for quantifying physical layer security of MIMO-SDM systems
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