CHARACTERISTICS OF QUANTUM DOTS LASER SUBJECTED TO CONVENTIONAL AND FILTERED OPTICAL FEEDBACK

Abstract

The quantum dots laser under the influence of conventional and filtered feedback is analyzed in the framework of the extended Lang-Kobayashi rate equations. The feedbacks comes from two separate branches: conventional and filtered optical feedback. We introduce a filtered feedback to control the unstable behavior of laser induced by conventional optical feedback. The stationary states, so called external filtered modes, of quantum dot laser under the influence of double feedback are obtained analytically. The locations of these modes are plotted in the plane of different parameters. Finally, it is shown that under appropriate conditions the laser system generate different behavior as continuous wave, periodic and chaotic behavior. In the case of equal feedback strengths in both channels it is shown that for a small feedback strength the phase portrait is a stable focus. With increase of the both feedback strengths the phase portrait became a limit cycle, and finally goes to a strange attractor.

Keywords

• conventional and filtered optical feedback
• externally cavity modes
• quantum dots lasers
• rate equations
• stationary states
• stable focus
• limit cycle
• strange attractor