Enhanced Silicon Ring Resonators Using Low-Loss Bends

The performances of enhanced micro-ring resonators on a silicon on insulator platform are reported. The ring resonators are composed using four low-loss advanced bends with 1μm-straight waveguides between the bends. The losses of advanced bends are nearly ten and fifteen times lower than those of normal bends when radii of bends are 2 and 3μm, respectively. The effective radii (R
_eff
) of the racetrack-rings are 2.5 and 3.5μm using advanced bends with 2 and 3μm-radii, respectively. The quality factor( Q) of 7800, finesse (F) of 175, free spectral range (FSR) of 35nm, and extinction ratio (ER) of >11dB have been measured from the racetrack ring resonator with R
_eff
of 2.5μm. From the racetrack ring resonator with Reff of 3.5μm, we obtained the Q of 19000, the of 287, the FSR of 23nm, and the ER of >10dB at C-bands.