Fig. 1. GaNOI nonlinear photonics platform

Fig. 2. (a) NIR optical frequency comb generation in sputtered AlN microring resonators^[18]; (b) Near visible and green frequency comb generation via SHG, SFG and THG^[19]

Fig. 3. (a) Device schematic, (b) dispersion profile, and SEM images of (c) microring waveguide and (d) bus waveguide facet of a crystalline AlN microring resonator^[14] ; (e),(f) Broadband NIR and near visible band optical frequency comb generation^[21]

Fig. 4. (a) Schematic of Pockels soliton microcomb generation via OPO; (b)-(c) Comb initiation and expansion, and (d) the experimental setup^[28]

Fig. 5. (a) FWM spectrum from a 3-mm-long GaN waveguide with 250 mW pump power; (b) FWM conversion efficiency vs. pump power^[31]

Fig. 6. (a)-(d) Fabrication procedures of GaN microring resonators; (e)-(f) SEM images of the ring waveguide and the bus waveguide in a GaN microring resonator^[17]

Fig. 7. (a) Chaotic frequency comb under TM₀₀ pump; (b) Soliton microcomb under TM₀₀ pump; (c) Raman assisted chaotic Kerr comb with TE₀₀ pump^[17]