Multidimensional controllable sunflower beams: turbulence-resistant encoding in free-space optical communication

Area of Science:

• Optical physics
• Free-space optical communication

Background:

• Atmospheric turbulence distorts orbital angular momentum (OAM) modes, limiting free-space optical (FSO) communication.
• Existing methods struggle with OAM mode distortion in FSO systems.

Purpose of the Study:

• To develop a turbulence-resilient optical field with multidimensional controllability for FSO communication.
• To establish control rules for the proposed optical field's morphology.
• To demonstrate robust data transmission using a multidimensional encoding scheme.

Main Methods:

• Superformula-phase modulated circular Airy beams were used to create a sunflower-structured optical field.
• Systematic exploration of a six-parameter space (m, n1, n2, n3, a, b) to define petal morphology.
• Pearson correlation coefficient (PCC) was used for quantitative evaluation of topological structure preservation.
• A multidimensional encoding scheme multiplexing petal number, morphology, and symmetry factors was proposed.
• Convolutional Neural Network (CNN)-based intelligent decoder was employed for image transmission.

Main Results:

• Precise control rules for petal morphology were established.
• Topological structures of the beams demonstrated robustness against atmospheric turbulence.
• Successful 8-bit grayscale image transmission was achieved with a Bit Error Rate (BER) of 0.076 under specific turbulence conditions (Cn2=5×10^-17 m^-2/3).

Conclusions:

• A novel multidegree-of-freedom controllable optical field with turbulence resilience was demonstrated.
• The proposed multidimensional encoding scheme offers a new paradigm for coded optical communication in complex atmospheric environments.
• This research advances FSO communication by mitigating turbulence-induced distortions.