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arXiv · 2604.23417

Optimum-Transmission Free-Space Optical Communications

Prajit Dhara·Babak N. Saif·Jeffrey H. Shapiro·Saikat Guha
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Abstract

Slepian developed the Prolate Spheroidal Wavefunction (PSW) spatial-mode basis, which forms the normal modes of the Fresnel-propagation kernel of a free-space optical communications channel bookended by hard-circular apertures. The zero-th order PSW mode has the highest power-transfer eigenvalue, exciting which on the transmitter side therefore maximizes the transmissivity for single-spatial-mode communications. We show that the transmissivity performance of this fundamental PSW mode can be obtained by an aperture-truncated Gaussian beam of an optimized beam waist, despite the two mode shapes deviating from one another in the near-field regime.

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Prajit Dhara, Babak N. Saif, Jeffrey H. Shapiro, Saikat Guha. 2026-04-25. Optimum-Transmission Free-Space Optical Communications. https://arxiv.org/abs/2604.23417

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