Tom Gavrielides

Air Force Research Laboratory, USA

 

Semiconductor lasers subject to delayed polarization rotated feedback

 

We examine several system configurations in which one or more semiconductor lasers are coupled through polarization rotated delayed feedback. We summarize our experimental and theoretical results for a single diode laser, steady, periodic and chaotic states under the influence of the polarization feedback. The unstable TM steady state without feedback now becomes an injection driven state as theoretical results agree quite well with the experiments. Additionally, we show that the two chaotic lasing polarizations are in a driven synchronization state. Further, we summarize the results for unidirectional coupled with rotated polarization of two diode lasers and show that synchronous time, perfect synchronization and inverse synchronization are obtained.  We also examine the steady states, and periodic states with a particular emphasis in square wave pulsations. Experiments and numerical computations are offered for stripe lasers as well as for VCSELs. Additional configurations of the two coupled face to face system with delayed rotated polarization are examined and new results, experimental and theoretical, are outlined. Finally, we show that square wave pulsations are robust, span a large feedback region and coexist with the steady states of the system.