Octave-spanning soliton optical frequency comb based on AlN microring resonator (Invited)

Self-reference Dissipative Kerr Solitons (DKSs) based on optical microring resonators have a wide range of applications, such as frequency synthesizers, coherent communication, astronomical spectrometer calibration, precision measurements, optical clocks, dual-comb spectroscopy, etc. The directly accessing octave-spanning DKS has been obtained in silicon nitride and lithium niobate microresonators. Here, a simple method that can directly access the octave-spanning DKS in an aluminum nitride (AlN) microring resonator via a single pump was proposed. The TE₀₀ and TE₁₀ modes act as the pump resonance and auxiliary resonance modes, respectively, which had the resonant frequencies close to each other, and the auxiliary mode on red detuning side could effectively balance the thermal drag effect during the formation of soliton. The pump wavelength was tuned slowly to access a stable soliton comb with a bandwidth of 1100-2300 nm and the maximum soliton existence range of 10.4 GHz (83 pm), which was the first time an octave-spanning Kerr soliton had been obtained on the AlN platform. The stable octave-spanning DKS with large soliton accessing window could be obtained in this scheme using a single pump, which was different from other schemes with additional complex controls means and equipments.