Target-wavelength-trimmed second harmonic generation with gallium phosphide-on-nitride ring resonators

Abstract

We demonstrate post-fabrication target-wavelength trimming with a gallium phosphide on silicon nitride integrated photonic platform using controlled electron-beam exposure of hydrogen silsesquioxane cladding. A linear relationship between the electron-beam exposure dose and resonant wavelength red-shift enables deterministic, individual trimming of multiple devices on the same chip to within 30 pm of a single target wavelength. Second harmonic generation from telecom to near infrared at a target wavelength is shown in multiple devices with quality factors on the order of 10 4 . Post-fabrication tuning is an essential tool for targeted wavelength applications including quantum frequency conversion.

Nonlinear optics in gallium phosphide cavities: simultaneous second and third harmonic generation

“…The maximum predicted value of η DTHG here is limited by material absorption, and may be enhanced by operating with a pump whose TH wavelength lies within the transparency window of GaP. Additional resonance tuning may be achieved through the use of external temperature control [23,53] or application of external cladding [54]. The ideal predicted value of ζ is lower than what was measured here, which can be attributed to undercoupling to the SH and TH modes.…”