Experimental investigations on the dynamical characteristics of pulse packages in a monolithically integrated amplified feedback laser

Under suitable external perturbation such as optical feedback, optical injection or optoelectronic feedback, semiconductor lasers can be driven to realize diverse dynamic outputs including period-one, period-two, multi-period, pulse packagesPPs), chaos, etc., which have potential applications in optical secure communications, microwave photonics, lidar, high speed random signal generation, etc.. For the PPs dynamics, most of previous relevant investigations are usually based on a system composed of discrete elements. In this work, we experimentally investigate the PP dynamical characteristics in a three-section monolithically integrated amplified feedback laserAFL) composed of a distributed feedbackDFB) laser section, a phaseP) section, and an amplified feedbackA) section. For the AFL, the sections P and A act as a compounded feedback cavity in which the feedback phase and strength can be varied by adjusting the current in section PIP) and the current in section AIA), respectively. Via the power spectrum and self-correlation function curve of the time series output from the AFL, the influences of IP and IA on repeated frequencyPP) and regularity of PPs are analyzed in detail. The results indicate that, for the section DFB, whose currentIDFB) is biased at a relatively large level, the AFL can realize two-mode oscillation. After further choosing appropriate IP and IA, the AFL can behave as the dynamical state of PPs. Under IDFB=86.15 mA and IP=96.00 mA, through varying IA in a range of 6.50-10.50 mA, there exist two separated regions for IA to make the AFL operate at PPs. For the region with relatively small value of IA, both PP and the secondary maximum) of self-correlation curve characterizing the regularity of PPs monotonically decrease with the increase of IA. However, for the region with relatively large value of IA, with the increase of IA, PP first decreases and then fluctuates in a tiny range, but first increases, and further reaches an extreme value, and then decreases. Under IDFB=86.15 mA and IA=9.00 mA, the output characteristics of PPs are significantly affected by IP. With IP increasing from 90.5 mA to 96.5 mA, PP first decreases, and then increases after reaching a minimal value, meanwhile shows an approximately opposite variation trend. Finally, for IDFB=86.15 mA, the mapping of PPs in the parameter space of IP and IA is given and the evolution regularities of PPs are also presented.