Chaotic dimension enhancement by optical injection into a semiconductor laser under feedback

Optical injection into a chaotic laser under feedback is investigated for dimension enhancement. Although injecting a solitary laser is known to be low-dimensional, injecting the laser under feedback is found to enhance the correlation dimension D₂ in experiments. Using an exceptionally large data size with a very large reconstruction embedding dimension, efficient computation is enabled by averaging over many short segments to carefully estimate D₂. The dimension enhancement can be achieved together with time-delay signature suppression. The enhancement of D₂ as a fundamental geometric quantifier of attractors is useful in applications of chaos.