Waveguide electro-optic modulator using population depletion in a Schottky diode

A waveguide middle-infrared electro-optic modulator working at room temperature is demonstrated. It contains only six quantum wells. A reverse biased Schottky diode is used to deplete the electronic population in quantum wells and to modulate the intersubband absorption coefficient. The 14% modulation could easily be enhanced by optimizing the quantum well overlap with the optical guided mode of the waveguide.