Reconfigurable Few-Mode Laser Source Based on a WRC-FPLD Coupled With a Microring Resonator

We propose and experimentally demonstrate a reconfigurable few-mode laser source through coupling a weak resonant-cavity Fabry-Perot laser diode (WRC-FPLD) to a microring resonator (MRR), in which the MRR is utilized as an external cavity to implement self-injection. For such a scheme, when the feedback strength from the MRR to the WRC-FPLD is strong enough, the laser can enter a stable single-mode self-injection locking (SIO) state. Continuously increasing the feedback strength, two-mode and three-mode lasing states can be realized. Furthermore, the wavelength of few-mode lasing can be adjusted within dozens of GHz by varying the temperature of the MRR. Additionally, under relatively weak feedback strength, the laser exhibits an unlocked single-mode lasing state, which undergoes quasi-periodic bifurcation to a chaotic state, and finally reaches SIO with the increase of feedback strength. Under an optimized feedback strength, the effective bandwidth of the chaotic state arrives at 12.81 GHz. Such a reconfigurable few mode laser source possesses some advantages, such as miniaturization, stability, and tunability, and it has application prospects in many fields, including mode-division multiplexing, optical sensing, and on-chip signal processing.