Abstract
We have analyzed the temperature stability of a MOS-capacitor microring optical modulator that was designed for critical coupling. We found that free carrier injection through DC bias control can compensate the extinction ratio (ER) drop that was caused by temperature drifting. 0.22 °C temperature drifting would drop the ER to 5dB without DC bias and 8.7V DC bias could extend the 5dB limit to 1.86°C temperature drifting. © 2009 IEEE.