Investigation On The Nonlinear Dynamics Of A Monolithically Integrated Semiconductor Laser Under Optical Injection

Photonic integrated circuits(PICs) have been quickly developing in recent years to meet the general trend of optical component microminiaturization. Compared with those setups composed of discrete components, PICs possess some unique virtues such as smaller size, lower cost, better stability, and better reproducibility via mass production. As one kind of PICs, monolithically integrated semiconductor lasers(MISLs) attract intensive attention due to their distinctive features. Accordingly, the nonlinear dynamics of MISLs and their applications in optical microwave generation, high-speed physical random bit acquisition, chaos synchronization and communication and clock recovery have been reported consecutively. Meanwhile, the most relevant investigations only focused on solitary MISL devices and pay little attention to the case where an external perturbation is introduced into the MISL.This article investigates the nonlinear dynamics of a three-section MISL experimentally and emphasizes the analysis on how the introduction of an external optical injection further regulates and controls the dynamical characteristics of the MISL. The experimental results demonstrate that, the MISL can be treated as a normal DFB laser when the phase section and gain section are unbiased, the output power increases rapidly and the peak wavelength shifts towards longer wavelengths with the increase of IDFB, nevertheless, the influences of IP and IG are too weak. Furthermore, diversely dynamical states including the stable state as well as the so-called period-one, period-two, multi-period, and chaotic states can be observed through adjusting the currents of the three sections. However, the chaotic operation region of the solitary MISL is very small in the parameter space of IG and IP, where careful adjustment is needed, which may partly restrict the chaos-based applications of MISL. After introducing an external optical injection, the MISL originally operating at other dynamical states can always be driven into chaotic state under suitable injection ratio and frequency detuning, for the solitary MISL originally operating at chaotic state, an external optical injection may also drive the MISL into other dynamical states, and however, there still exists a wide chaotic region mainly located at relatively weak injection ratio, additionally the bandwidth of chaotic signal can be enhanced by suitable optical injection. Finally, the mappings of dynamical states in the parameter space of injection ratio and frequency detuning are presented and analyzed for different values of IG when IDFB and IP are fixed.