Nanolithographic Waveguides, Couplers and Ring Resonators made of Si3N4 and AIN for Photonics and Quantum Technologies

Photonic integrated functionalities based on silicon nitride ($\mathrm{Si}_{3} \mathrm{~N}_{4}$) and aluminum nitride (AlN) fabricated and characterized on wafer level are presented here. The design comprises waveguides, couplers, and rings for C-band and L-band applications. Propagation losses of $0.25 \mathrm{~dB} / \mathrm{cm}$ for LPCVD-Si ${ }_{3} \mathrm{~N}_{4}, 0.6 \mathrm{~dB} / \mathrm{cm}$ for ICPCVD-Si3N4 and $1 \mathrm{~dB} / \mathrm{cm}$ for PECVD-Si N4 were achieved. Wafer level characterization shows grating couplers with a measured maximum coupling coefficient in the range of -13.92 dB to -16.03 dB over the whole wafer. Moreover, ring resonances with quality factors higher than $19000\left(\mathrm{Si}_{3} \mathrm{~N}_{4}\right)$ and $3000(\mathrm{AlN})$ for $25 \mu \mathrm{~m}$ ring radius were achieved.