The development of ultrahigh-quality-factor (Q) silicon-on-insulator (SOI) microring resonators based on silicon wire waveguides is presented. An analytical description is derived, illustrating that in addition to low propagation losses the critical coupling condition is essential for optimizing device characteristics. Propagation losses as low as 1.9±0.1 dB/cm in a curved waveguide with a bending radius of 20 μm and a Q factor as high as 139.000±6.000 are demonstrated. These are believed to be the highest values reported for a curved SOI waveguide device and for any directly structured semiconductor microring fabricated without additional melting-induced surface smoothing.
© 2004 Optical Society of America
Jan Niehusmann, Andreas Vörckel, Peter Haring Bolivar, Thorsten Wahlbrink, Wolfgang Henschel, and Heinrich Kurz, "Ultrahigh-quality-factor silicon-on-insulator microring resonator," Opt. Lett. 29, 2861-2863 (2004)