Nonlinear dynamics of hybrid integrated laser based on self-seeding of a DFB-LD by using a Si3N4 microring resonator as filter feedback

In this work, we experimentally investigate the nonlinear dynamics of a hybrid integrated laser (HIL) composed of a distributed feedback laser diode (DFB-LD) and a tunable silicon-nitride photonic chip-based microring resonator (MRR), where the drop-port of MRR is connected to a Sagnac loop via a variable optical coupler (OC). Through varying the voltages loaded on the MRR (VMRR) and the variable OC (VOC), the central frequency and feedback coefficient of filter feedback can be adjusted, respectively. Via observing the optical power (time series), RF spectra, optical spectra of the HIL output, and calculating the Lyapunov exponent of the time series, diverse dynamical states including period one (P1), period two (P2), period four (P4), quasi-period (QP), chaos (CO) and self-injection locking (LO) can be distinguished. For different combinations of VMRR and VOC, the evolution routes for the nonlinear dynamical states of the HIL with the bias current of the DFB-LD (IDFB) are inspected and analyzed. By mapping the dynamical states in the parameter space of IDFB and VOC, the parameter regions for the HIL behaving different dynamical states are determined.