We have recently published a new paper in which we study the post-processing trimming of microring resonators - enabled through the absence of top cladding of the cavity - to finely tune its geometrical dispersion. This lets us tailor the microcomb bandwidth, which is strongly controlled by the geometrical dispersion, in a fine way.
This work, led by Greg and published in Applied Physics Letters as an editor's pick, shows that the optical loss of the ring, which is also critical for microcomb generation, is not impacted by the dry etch triming and that only the spectral envelope of the dissipative Kerr soliton frequency comb is modified, as expected from theory.
Moille, G., D. Westly, N. George Orji, and K. Srinivasan, "Tailoring broadband Kerr soliton microcombs via post-fabrication tuning of the geometric dispersion", Applied Physics Letters, vol. 119, pp. 121103, 2021