Free Space Optical Communication Using Orbital Momentum Multiplexing and Spatial Diversity Techniques

Conclusion: The study was set out to investigate and model the propagation of Laguerre-Gaussian optical beams possessing a degree of freedom, the orbital angual momentum, through atmospheric turbulence. The study aims for modeling an orbiatl angular momentum multiplexing setup and a new diversity technique was employed to mitigate the turbulence-induced system flaws for the first time. The phase and amplitude distorted optical beams are simulated and analyzed, channel crosstalk and efficiency values are ensemble in the matrix. Utilizing the numerical simulation results allowed further system performance analysis such as channel efficiency and channel interference fluctuations, the probability of outage and bit-error-rate curves.

The spatial diversity method has been widely used for wireless communications and free space optical communications, but the usage of OAM carrying beams as diversity channels, enables the transmission of information with higher reliability and security. On the other hand, multiplexing is a well-known method to increase the transmission capacity in communication systems. To accomplish a high capacity, secure and reliable transmission, more case studies and local realizations are required for the combination of mulitplexing and diversity techniques with regards to Laguerre-Gaussian beams. Exploring optimal orthogonal states and feasible detection strategies as future research ideas can facilitate achievement of this target.