Key points are not available for this paper at this time.
In this feature section, we have six contributions from pioneering groups working on optical chaos synchronization and encryption. The two more widely used techniques to make a semiconductor laser operate in a chaotic regime are optical and electrooptical feedback. Both techniques are well represented in this feature issue. The first four papers deal with optical feedback. The two other papers concentrate on electro-optical feedback.
Donati et al. (Sun,) studied this question.