Quantum Optics for Engineers

11

Secure Interferometric Communications in Free Space

11.1  Introduction

The N-slit laser interferometer (NSLI) was first introduced as an alternative applicable to secure free-space optical communications in 2002 (Duarte, 2002). Albeit its initial propagation distance in the laboratory was only 15 cm, it was envisioned as an interferometric tool ideally suited for propagation in the vacuum, or outer space (Duarte, 2002). Subsequently, NSLI experiments have also been conducted over hundreds of meters, in the field, via open atmosphere (Duarte et al., 2010, 2011).

The idea is that an N-slit interferometric signal, designated as an interferometric character or a series of interferometric characters, can be used to transmit information securely ...