Abstract: Silicon-based photonic devices，including stimulated emission from Si diodes，resonant cavity enhanced (RCE) photodiodes with quantum structures，metal oxide semiconductor (MOS) optical modulators with high frequency，SOI optical matrix switches and wavelength tunable filters，are reviewed.Emphasis is placed on our recent results for SOI-based thermo-optic waveguide matrix switches with low insertion loss and fast response.A folding re-arrangeable non.blocking 4 x 4 matrix switch with total internal reflection (TIR) mirrors and a first blocking 16 x 16 matrix were fabricated on S01 wafer.The extinction ratio and the crosstalk are excellent.The insertion loss and the polarization-dependent loss (PDL) at 1.55μm increase slightly with longer device length，more bending，and more intersecting waveguides.The insertion losses are expected to decrease by 2～3dB when antirefleetion films are added to the ends of the devices.The rise and fall times of the devices are 2.1 and 2.3μs，respective1y.

Key words: SOI,  optical switch matrix,  photodiodes,  optical interconnection