Operation and Optimization of Silicon-Diode-Based Optical Modulators

An optical modulator in silicon based on a diode structure has been operated in both forward and reverse bias. This modulator achieves near state-of-the-art performance in both modes, thereby making this device ideal for comparing the two modes of operation. In reverse bias, the device has a V pi L of 4.0 V.cm and a bandwidth of 26 GHz. In forward bias, the device is very sensitive, a V pi L as low as 0.0025 V.cm has been achieved, but the bandwidth is only 100 MHz. A new geometry for a reverse-bias device is proposed, and it is predicted to achieve a V pi L of 0.5 V.cm.