Fabrication of a bonded LNOI waveguide structure on Si substrate using ultra-precision cutting

The heterogeneous integration of an LNOI waveguide device on a mature Si platform is interesting for the creation of a future high density and multi-functional platform. This paper reports the fabrication of a bent LNOI waveguide on Si substrate using surface activated bonding with a Si nanoadhesive layer and post-bond ultra-precision cutting at room temperature. This bonding method demonstrates the sufficient bond strength between an LN wafer and thermally grown SiO 2 to withstand ductile-mode cutting for waveguide fabrication. In this work, the width, height, and bent radius of the ridged LNOI waveguide on Si substrate were approximately 5, 2.5, and 300 μ m, respectively. These room-temperature bonding and cutting methods are expected to fabricate various heterogenous devices with a large coefficient of thermal expansion mismatch between dissimilar materials, not just LNOI/Si waveguide devices.