A Review on Optical Beam Phase Correction Techniques for Ground to Space Free-Space Optical Communication

Abstract

The Free Space Optical Communication (FSOC) links face significant challenges and issues resulting in an unattainable level of reliability and high performance due to phase distortions, scintillation, beam wandering, and atmospheric turbulence. In order to address these concerns, a comprehensive analysis of independent techniques to correct the optical beam steering and advanced compensation strategies is presented. For both terrestrial and ground to space FSOC applications, this assessment evaluates theoretical analyses, modelling studies, hardware implementations, and experimental demonstrations pertaining to the various optical beam phase correction methods. Adaptive optics, feedback-based beam steering, optical phase conjugation, non-mechanical phase correction methods and error correction techniques classify the various methods used for improving the optical beam performance. The comparative analyses in the reviewed studies indicate that traditional Adaptive Optics (AO) systems are very effective at weak and moderate turbulence levels but that neural network-based controllers perform better under rapidly changing or strong turbulence conditions. Furthermore, the use of hybrid schemes that employ various compensation mechanisms consistently resulted in increased link reliability and performance; however, the added level of complexity associated with hybrid schemes detracts from the overall efficiency of the system. This review provides a detailed analysis of the various state-of-the-art phase correction systems currently available, comparative performance data, and recent developments in the FSOC field.