Optical signal enhancement in erbium-doped yttria-stabilized zirconia heterogeneously integrated on silicon nitride waveguides

Silicon (Si) photonics is a solid candidate to address the challenges of emerging communication systems with an increasing number of interconnected devices. However, the properties of Si prevent on-chip integration of key functions including light amplification. The increasing demand for efficient photonic materials compatible with silicon platforms, at low economic and environmental costs, opened the possibility to the integration of rare-earth doped oxides for the development of integrated optical amplifiers. In this context, this paper reports on an heterogeneously integrated photonic device based on erbium-doped yttria-stabilized zirconia on silicon nitride (SiNx) waveguides. Average erbium concentration of 1.06×1021 cm−3 was implemented in a 220 nm thick oxide layer. We demonstrated on-chip signal amplification with a measured signal enhancement of 7.45 dB for 3 mm long waveguide, as well as material losses of 10.8 dB·cm⁻¹ and modal gain with a value as high as 32.5 dB·cm⁻¹ for 1.1 mm long waveguide at a wavelength of 1530 nm. Silicon photonics is promising for developing increasingly complex communication systems but faces challenges in integrating key functionalities such as light amplification. Here, the authors demonstrate a heterogeneously integrated photonic device using erbium-doped yttria-stabilized zirconia on silicon nitride waveguides, achieving significant on-chip signal amplification, which advances efficient photonic materials compatible with silicon platforms.