Enhancing secure transmission of ultra-high order QAM via delta-sigma modulation integrated with radial basis...

This paper proposes and experimentally demonstrates an ultra-high order signal security enhancement method based on delta-sigma modulation (DSM). We employ a radial basis function neural network (RBFnn) to enhance Henon chaos, effectively avoiding the degradation of chaotic dynamics, and increasing the key space from 10⁵⁴ to 10³⁸⁵. In the experimental demonstration, we achieved high-security transmission of 16384QAM over 25 km in an intensity-modulated direct detection (IMDD) system based on DSM. The experimental results show that the ultra-high order transmission scheme based on RBFNN-chaos and DSM has superior security, with a key sensitivity of up to 10^-16.