High-speed silicon electro-optical modulator that can be operated in carrier depletion or carrier injection mode

A high-speed silicon optical modulator has been demonstrated which can operate either in forward bias using carrier injection, or in reverse bias using carrier depletion. In forward bias, the device requires less than 10 mW of drive power, but has a low bandwidth of 100 MHz. In reverse bias, the device has a nearly flat response to 18 GHz, but requires 700 mW for large modulation depths.