Effects of Oceanic Turbulence on Orbital Angular Momenta of Optical Communications

Shuang Zhai,Yixin Zhang,Yun Zhu,Zhengda Hu

doi:10.3390/jmse8110869

Shuang Zhai, Yixin Zhang + Show 2 more

Open Access

https://doi.org/10.3390/jmse8110869

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Abstract

The propagation properties of Laguerre-Gaussian beams in oceanic turbulence are investigated for both single-photon and biphoton cases. For single-photon communication, the channel capacity and trace distance are employed, both of which effectively reveal the communication performance via different viewpoints. For the biphoton case, we consider distributions of quantum resources including entanglement and quantum coherence. Turbulence conditions with a larger inner-scale and anisotropic factors, higher dissipation rate of kinetic energy, lower dissipation rate of the mean-squared temperature, and lower temperature-salinity contribution ratio combined with longer wavelength and an appropriate range of optimal beam width are beneficial to communication performances. Our results provide theoretical significance to improve the orbital-angular-momentum communication via oceanic turbulence.

Highlights

Optical vortex beams, carrying orbital angular momenta (OAM), may find potential applications in wireless communication systems [1,2]
Baghdady et al [16] explored the effects of turbulence on the propagation of vortex beams with optical vortices and gained considerable interest due to the possibility of implementing quantum optical communication links with OAM modes
We have quantitatively described the effects of the oceanic turbulence on channel capacity, trace distance, concurrence and trace-distance coherence of LG beams

Summary

Introduction

Optical vortex beams, carrying orbital angular momenta (OAM), may find potential applications in wireless communication systems [1,2]. In addition to polarization of photons, OAM provides a new degree of freedom for encoding non-classical information This encoding manner may possess more security [3] and higher capacity [4]. The understanding of propagation properties for quantum resources (such as entanglement and quantum coherence) of OAM photons in turbulent ocean is crucial. We consider the influences of oceanic turbulence on the channel capacity and trace distance in the single-photon communication case and entanglement and quantum coherence in the biphoton communication case. Both the single-photon communication and biphoton quantum communication are considered.

Laguerre-Gaussian Beams Propagating through Turbulent Ocean

Single-Photon Communication Case

Biphoton Communication Case

Channel Capacity and Trace Distance in Single-Photon Communication

Quantum Entanglement and Quantum Coherence in Biphoton Communication

Conclusions