Integrated folding 4×4 optical matrix switch with total internal reflection mirrors on SOI by anisotropic chemical etching

A folding rearrangeable nonblocking 4×4 optical matrix switch was designed and fabricated on silicon-on-insulator wafer. To compress chip size, switch elements (SEs) were interconnected by total internal reflection (TIR) mirrors instead of conventional S-bends. For obtaining smooth interfaces, potassium hydroxide anisotropic chemical etching of silicon was utilized to make the matrix switch for the first time. The device has a compact size of 20×1.6 mm² and a fast response of 7.5 μs. The power consumption of each 2×2 SE and the average excess loss per mirror were 145 mW and -1.1 dB, respectively. Low path dependence of /spl plusmn/0.7 dB in total excess loss was obtained because of the symmetry of propagation paths in this novel matrix switch.