# Advanced Beam Detection for Free-Space Optics Operating in the Mid-Infrared Spectra

## TL;DR

This paper introduces a new detector for free-space optical communication that works in the mid-infrared range, improving beam tracking and data reception.

## Contribution

A novel integrated detector module for mid-infrared optical communication that combines beam tracking and data reception.

## Key findings

- The detector module successfully monitors beam position and receives data in the mid-infrared range.
- Laboratory experiments validated the signal bandwidth and position transfer function of the quadrant detector.
- The design simplifies mobile FSOC systems requiring accurate transceiver tracking.

## Abstract

The article addresses the challenges of beam position tracking in Free-Space Optical Communication (FSOC) systems. A review of available photodetector technologies is presented, highlighting their operating principles and applications in optical links. The analysis indicates that most current monitoring devices function with the visible and near- or short-infrared ranges. However, due to the propagation characteristics of radiation in terrestrial environments, the mid-wave infrared (MWIR) region offers particularly promising opportunities. To the end, the work introduces a novel detector module based on an MWIR quadrant detector capable of simultaneously performing two essential tasks: monitoring beam position and receiving transmitted data. Such an integrated approach has the potential to significantly simplify the design of mobile FSOC systems, especially those requiring accurate transceivers’ tracking. The concept was validated through laboratory experiments on an MWIR link model, where both the signal bandwidth and position transfer function of the quadrant detector were examined.