Investigation of 90° submicrometer radius bends of metal-insulator-silicon-insulator-metal waveguides

We theoretically and experimentally investigate 90° submicrometer radius bends (SRB) of metal-insulator-silicon-insulator-metal (MISIM) waveguides that are plasmonic waveguides fabricated with standard CMOS technology. We focus on the bends of MISIM waveguides with a wide (e.g., 160-220 nm) silicon line. This study shows that the bend efficiently turns the direction of the MISIM waveguide by 90° if its radius is about 0.7 μm. Moreover, we discuss the fact that the bend may be superior to a SRB of a silicon photonic waveguide when it is used to implement a ring resonator with a high quality factor and small volume.