Silicon-wires and compact multi-mode interference splitters with an uneven splitting-ratio

We report the fabrication and accurate measurement of propagation and bending losses in silicon wires with submicron dimensions fabricated on silicon-on-insulator wafer. Propagation loss of 0.71±0.03dB/mm for the TE polarization was measured at the 1.55µm. Loss of per 90° bend is measured to be 0.01dB for a bending radius of 5µm. Three types of compact MMI splitters with different splitting-ratios were fabricated and measured. The splitting-ratios are respectively 50∶50, 15∶85 and 28∶72. They exhibited low excess losses of about 1.5∼3.9dB. The splitting-ratios were consistent with the design values.