# Characterization of an underwater channel for quantum communications in the Ottawa River

## TL;DR

This study investigates the underwater optical channel in the Ottawa River, analyzing turbulence effects on beam propagation and assessing the potential for quantum communication using polarization and spatial modes.

## Contribution

It provides real-time turbulence characterization and evaluates the feasibility of quantum communication through underwater channels.

## Key findings

- Turbulence effects quantified via Zernike coefficients.
- Feasibility demonstrated for transmitting polarization and spatial modes.
- Real-time wavefront analysis achieved.

## Abstract

We examine the propagation of optical beams possessing different polarization states and spatial modes through the Ottawa River in Canada. A Shack-Hartmann wavefront sensor is used to record the distorted beam's wavefront. The turbulence in the underwater channel is analysed, and associated Zernike coefficients are obtained in real-time. Finally, we explore the feasibility of transmitting polarization states as well as spatial modes through the underwater channel for applications in quantum cryptography.