Photonic Damascene Process for Integrated High-Q Microresonator Based Nonlinear Photonics

摘要

High confinement, integrated silicon nitride (SiN) waveguides have recentlyemerged as attractive platform for on-chip nonlinear optical devices. Thefabrication of high-Q SiN microresonators with anomalous group velocitydispersion (GVD) has enabled broadband nonlinear optical frequency combgeneration. Such frequency combs have been successfully applied in coherentcommunication and ultrashort pulse generation. However, the reliablefabrication of high confinement waveguides from stoichiometric, high stress SiNremains challenging. Here we present a novel photonic Damascene fabricationprocess enabling the use of substrate topography for stress control and thinfilm crack prevention. With close to unity sample yield we fabricatemicroresonators with $1.35\,\mu\mathrm{m}$ thick waveguides and optical Qfactors of $3.7\times10^{6}$ and demonstrate single temporal dissipative Kerrsoliton (DKS) based coherent optical frequency comb generation. Our newlydeveloped process is interesting also for other material platforms, photonicintegration and mid infrared Kerr comb generation.