Waves, modes, communications, and optics: a tutorial

By David A. B. Miller. Advances in Optics and Photonics, 2019

190 citations recorded by the source corpus.

Modes generally provide an economical description of waves, reducing complicated wave functions to finite numbers of mode amplitudes, as in propagating fiber modes and ideal laser beams. But finding a corresponding mode description for counting the best orthogonal channels for communicating between surfaces or volumes, or for optimally describing the inputs and outputs of a complicated optical system or wave scatterer, requires a different approach. The singular-value decomposition approach we describe here gives the necessary optimal source and receiver “communication modes” pairs and device or scatterer input and output “mode-converter basis function” pairs. These define the best communication or input/output channels, allowing precise counting and straightforward calculations. Here we introduce all the mathematics and physics of this approach, which works for acoustic, radio-frequency, and optical waves, including full vector electromagnetic behavior, and is valid from nanophotonic scales to large systems. We show several general behaviors of communications modes, including various heuristic results. We also establish a new “M-gauge” for electromagnetism that clarifies the number of vector wave channels and allows a simple and general quantization. This approach also gives a new modal “M-coefficient” version of Einstein’s A&B coefficient argument and revised versions of Kirchhoff’s radiation laws. The article is written in a tutorial style to introduce the approach and its consequences.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/859c99aa8bf5f5434ebbf3a7239ba3d94637a5b7

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Citations in the corpus

Communicating With Large Intelligent Surfaces: Fundamental Limits and Models (2019, unknown): “[35], [49].”
Near-Field MIMO Communications for 6G: Fundamentals, Challenges, Potentials, and Future Directions (2023, background): “Precisely, based on the expansion of prolate sphe-roidal wave functions, it is proved in [10] that near-field near-field spatial DoFs are proportional to the product of the BS and UE array apertures and inversely proportional to the BS-UE distance.”
Communicating With Extremely Large-Scale Array/Surface: Unified Modeling and Performance Analysis (2021, unknown): “In fact, the use of continuous surface or even volume for active signal transmission/reception was studied almost two decades ago (see [36], [37] and references therein), and it has gained revived interest recently as a promising B5G transmission technology [17]–[22].”
A Tutorial on Near-Field XL-MIMO Communications Toward 6G (2023, unknown): “It is also worth mentioning that some elegant approximate DoF expressions were obtained in [184], [185].”
Inference in artificial intelligence with deep optics and photonics (2020, methodology): “Optical computing systems promise massive parallelism 4 in conjunction with small device form factors and, in some implementations, little to no power consumption 5 .”