Various nonlinear transitions of a self-assembled quantum dot (SA-QD) semiconductor laser subject to negative optoelectronic feedback

The delayed negative optoelectronic feedback DNOEF system of the self-assembled quantum dot (SA-QD) semiconductor laser with DNOEF is numerically investigated. Bifurcation diagrams, time traces, and frequency spectra of the laser output, and the 2-D phase space portraits, are used to analyze the nonlinear transitions of the DNOEF system. In this study, delay times of the feedback were applied that were neither much smaller nor much greater than the relaxation time of the laser, thus most results for nonlinear transitions in this feedback system indicated a strong interaction between the loop frequency and the relaxation frequency of the laser. These nonlinear transitions were included 2-P, RP, and 3-P states. On the other hand, the CP states of the laser output was found within a narrow range of feedback delay time. Through the results, it was found that the laser enters chaotic pulse states when the natural time delay increases from 1.433 to 1.6 and the feedback strength − 0.32.