Performance characteristics of positive and negative delayed feedback on   chaotic dynamics of directly modulated InGaAsP semiconductor lasers
  The chaotic dynamics of directly modulated semiconductor lasers with delayed optoelectronic feedback is studied numerically. The effects of positive and negative delayed optoelectronic feedback in producing chaotic outputs from such lasers with nonlinear gain reduction in its optimum value range is investigated using bifurcation diagrams. The results are confirmed by calculating the Lyapunov exponents. A negative delayed optoelectronic feedback configuration is found to be more effective in inducing chaotic dynamics to such systems with nonlinear gain reduction factor in the practical value range. 
Bindu M. Krishna, Manu. P. John, V. M. Nandakumaran