Information-Theory-Based Complexity Quantifier for Chaotic Semiconductor Laser With Double Time Delays

The complexity properties of the chaotic signals generated by a chaotic semiconductor laser (SL) with double time delays are quantified numerically. A modified complexity quantifier, mean permutation entropy (MPE), based on information theory, is applied to fully characterize the chaotic complexity. The autocorrelation time (ACT) is also employed as a supplement quantifier. The numerical analyses of the MPE and the ACT have been performed extensively, and the effects of feedback rate, bias current, feedback delays, and linewidth enhancement factor are examined. The parameter regions leading to high chaotic complexity are identified successfully by the MPE. Besides, we also successfully quantify the chaotic complexity of the SL with three time delays. Hence, such information-theory-based MPE is an effective and universal complexity quantifier for a chaotic SL with multiple time delays, which is interesting and valuable for chaos communication systems.