Modulation bandwidth enhanced self-injection locking laser with an external high-Q microring reflector.

We propose and demonstrate a hybrid modulation bandwidth enhanced self-injection locking laser by butt coupling a commercial distributed feedback laser with an external high-Q silicon nitride microring reflector (MRR). The MRR keeps the laser in strong self-injection locking state with photon-photon resonance, which can realize direct modulation bandwidth enhanced and stable narrow linewidth single-mode output. With the further optimization of MRR parameters, the 3-dB modulation bandwidth and the linewidth of the hybrid laser are enhanced to 15.28 GHz from 7.70 GHz and narrowed to 4 kHz from 600 kHz, respectively. This work makes full use of the advantages of self-injection and integrated photonic technology, which has potential applications in many fields.