High-speed waveguide optical modulator made from GaSb/AlGaSb multiple quantum wells (MQWs)

We observe a large electroabsorption effect in a GaSb/AlGaSb MQW, and use it to make a waveguide modulator with a 10.5 dB on/off ratio and a 12dB insertion loss at a wavelength of 1.55?m. Our high-speed device has a 3dB rolloff frequency of 3.7 GHz.