Fabrication of Silicon-on-Diamond Substrate and Low-Loss Optical Waveguides

A simple, complementary metal-oxide-semiconductor (CMOS)-compatible fabrication technique is developed to demonstrate a robust silicon-on-diamond (SOD) substrate. The 2.5 μm × 700 nm waveguides with a spiral structure are fabricated on both SOD and conventional silicon-on-insulator (SOI) substrates, showing 0.74- and 0.54-dB/cm propagation loss, respectively. Finite element method (FEM) thermal simulation shows over 3× improvement in heat dissipation on a hybrid silicon laser structure when Si substrate is not a limiting factor.