Orbital Angular Momentum Based Physical Layer Security for Optical Communications Systems

This article introduces a promising approach referred to as “orbital angular momentum (OAM) based physical layer security,” that aims to enhance the security of free-space optical communications. The central innovation involves incorporating a pseudo-random key into the transmitted OAM beams. This key effectively obfuscates any potential eavesdroppers who might try to intercept the transmitted data. We demonstrate that by employing various OAM modes, it is feasible to create a key that will mislead an eavesdropper regarding the specific OAM mode that carries the information bits. Through the addition of the pseudo-random key, a specific OAM mode is transformed into a combination of numerous modes, causing confusion for an eavesdropper in determining the true transmitted mode. Consequently, the likelihood of correctly identifying the actual transmitted OAM mode is markedly diminished for Eve. This paper highlights the potential of OAM-based systems in establishing robust security measures for free-space optical communication systems. Furthermore, it contributes to the advancement of secure communication protocols, ensuring the integrity of sensitive data within challenging communication environments.