Bio-inspired compound-eye receiver with a focal-length gradient and CPC arrays for wide-field underwater optical communication

Underwater wireless optical communication (UWOC) is faced with the problems of energy attenuation, light intensity flicker, and beam diffusion caused by turbulence, absorption, and scattering in the actual marine environment, which limits the performance of the receiver. In order to improve the receiving field-of-view angle and sensitivity, a UWOC receiver based on the bionic compound-eye structure is proposed in this paper. The receiver combines a curved sub-eye array with a focal-length gradient and a compound parabolic concentrator array (CPCA), which can efficiently converge the incident light from a large field of view to a small-area detector through the secondary focusing mechanism. Simulation results show that the design can significantly improve the energy transmission efficiency in the ±40 ∘ field of view. Compared with the design without a focal-length gradient, the sub-eye design with a focal-length gradient improves the energy transmission efficiency by 8.9% at an incident angle of 40°. By building a water tank platform to simulate the ocean channel and adjusting the key parameters such as temperature, salinity, turbidity, and beam emission angle, the performance advantages of compound-eye lens in different channel conditions are verified experimentally.