Computed Coupling Efficiencies of Kolmogorov Phase Screens into Single-Mode Optical Fibers

TL;DR

This paper calculates how efficiently a Kolmogorov phase-distorted electromagnetic field couples into single-mode fibers at infrared wavelengths, considering adaptive optics corrections and specific telescope parameters.

Contribution

It introduces a method to compute coupling efficiencies using phase screens modeled by Karhunen-Loeve functions, including adaptive optics effects, for realistic telescope scenarios.

Findings

Coupling efficiencies depend on telescope size and atmospheric conditions.

Adaptive optics correction improves coupling efficiency.

Efficiency varies across J, H, and K bands.

Abstract

Coupling efficiencies of an electromagnetic field with a Kolmogorov phase statistics into a step-index fiber in its monomode regime of wavelengths are computed from the overlap integral between the phase screens and the far-field of the monomode at infrared wavelengths. The phase screens are composed from Karhunen-Loeve basis functions, optionally cutting off some of the eigenmodes of largest eigenvalue as if Adaptive Optics had corrected for some of the perturbations. The examples are given for telescope diameters of 1 and 1.8 m, and Fried parameters of 10 and 20 cm. The wavelength of the stellar light is in the J, H, or K band of atmospheric transmission, where the fiber core diameter is tailored to move the cutoff wavelength of the monomode regime to the edges of these bands.