Amplification in a Hybrid Erbium Silicon Photonic Waveguide

The monolithic integration of optical amplifiers and light sources on silicon-on-insulator (SOI) remains a significant challenge despite the widespread application of silicon photonic integrated circuits [1]. Current approaches for integrating active gain media onto silicon chips include the heterogeneous integration of III - V materials [2], parametric gain in materials such as gallium phosphide [3], and planar waveguide amplifiers based on erbium-doped optical thin films such as Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>, LNOI, and Si<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> [4]–[6]. Hybrid platforms that aim for monolithic integration of erbium-based amplifiers are particularly appealing due to their low cost, relatively simple fabrication processes, scalability, and compatibility with various standard foundry processes. These platforms have been successfully shown on Si<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> [7], [8], however, extending these approaches to the SOI platform is more challenging due to higher silicon waveguide losses, lower confinement of light in the gain medium, and two-photon absorption in silicon.