Interfacing of silicon-on-insulator nanophotonic circuits to the real world

Silicon-on-insulator material structure allows for very high light confinement in the silicon core due to its high refractive index. The advantages of this technology include the possibility to miniaturize devices and integrate different functions on a single chip, reduction of optical loss and power consumption and potential perspectives for low cost mass production in CMOS technology line. Together with these advantages some new problems appear in comparison to weakly guided light in silica-on-silicon components, causing additional challenges for researchers to be solved. Besides much higher demands for fabrication accuracy, high refractive index contrast introduces additional optical input/output coupling problems as well as much higher polarization sensitivity of nanophotonic structures. Here we will propose some solutions for these problems and illustrate them with designed and fabricated components.