Harmonic laser mode locking based on nonlinear microresonators

We summarize here our recent results on high-repetition-rate laser mode-locking via microring resonators. The recent realization of multiple wavelength oscillators based on high Q-factor resonators has profoundly impacted optical frequency combs for metrology and precision measurements and other areas. The ability to mode-lock these devices is important for achieving high-precision optical clocks in a monolithic format, offering enormous benefits in performance, cost, size, and power consumption for optical waveform synthesis, high-capacity telecommunications, optical analog-to-digital conversion, and many other applications. Here, we demonstrated a mode-locked laser based on a monolithic high Q resonator. This device produces stable, self-starting transform-limited optical pulses at 200.3 GHz, with a sub-100 kHz linewidth and extremely narrow amplitude noise bandwidth of <1 Hz. Stable operation of two slightly shifted spectral optical comb replicas, generating a highly monochromatic radiofrequency modulation with a linewidth of <10 kHz is also observed.