Adaptive Time-delay Hyperchaos Synchronization in Laser Diodes Subject   to Optical Feedback
  In this paper a proposal is made of an adaptive coupling function for achieving synchronization between two lasers subject to optical feedback.Such a control scheme requires knowledge of the systems' parameters. We demonstate that when these parameters are not available on-line parameter estimation can be applied. 
E.M.Shahverdiev and K.A.Shore