Simultaneous self-injection locking of two laser diodes to a single integrated microresonator

We both theoretically and experimentally investigate the dual-laser self-injection locking of two multifrequency laser diodes to different modes of an integrated Si3N4 microresonator. We observe simultaneous spectrum collapse of both lasers, as well as linewidth narrowing and high-frequency noise suppression, as well as strong nonlinear interaction of the two fields with each other. Simultaneous frequency and phase stabilization and coherent addition of output signal are observed for locking both lasers to the same mode.