Optical characterization of silicon-on-insulator-based single and coupled racetrack resonators

Silicon photonics is the emerging optical interconnect technology where integrated nanophotonic components allow reaching high device density and improved optical functionalities. One key component is the optical microresonator. A particular kind of microresonator is the racetrack resonator where straight waveguide sections are used to achieve a large value of the coupling coefficient with a bus waveguide for any light polarization state. It is our aim to study the performances of racetrack resonators fabricated on silicon on insulator via CMOS processing. We experimentally investigated different multiple resonator designs where box-shaped filter characteristic, Vernier effect, and coupled resonator induced transparency effects are obtained. We demonstrate that racetrack resonators are instrumental to several different functions in nanophotonics and that the actual lithographic process is fully capable of building these structures. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3596700]