Optimizing deep-space optical communication under power constraints

TL;DR

This paper analyzes the limits of deep-space optical communication under power constraints, showing how quantum noise impacts capacity and proposing structured receivers to improve efficiency.

Contribution

It introduces a theoretical framework for optimizing deep-space optical communication considering quantum noise and proposes structured receivers to enhance performance.

Findings

Scaling gap between modulation schemes identified

Quantum capacity limits characterized under noise

Structured receivers can improve signal concentration

Abstract

We investigate theoretically the efficiency of deep-space optical communication in the presence of background noise. With decreasing average signal power spectral density, a scaling gap opens up between optimized simple-decoded pulse position modulation and generalized on-off keying with direct detection. The scaling of the latter follows the quantum mechanical capacity of an optical channel with additive Gaussian noise. Efficient communication is found to require a highly imbalanced distribution of instantaneous signal power. This condition can be alleviated through the use of structured receivers which exploit optical interference over multiple time bins to concentrate the signal power before the detection stage.