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

TL;DR

This paper presents a method for post-fabrication wavelength tuning of gallium phosphide-on-nitride ring resonators using electron-beam exposure, enabling precise control of second harmonic generation at desired wavelengths.

Contribution

It introduces a controlled electron-beam trimming technique for deterministic wavelength tuning in integrated photonic resonators, achieving high precision and enabling targeted nonlinear optical applications.

Findings

Achieved wavelength tuning within 30 pm of target values.

Demonstrated second harmonic generation at specified wavelengths.

Established a linear relationship between electron-beam dose and wavelength shift.

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