High-speed InGaAlAs/InAlAs multiple quantum well optical modulators with bandwidths in excess of 20 GHz at 1.55 mu m

The modulator has a large on/off ratio, a low driving voltage (4 V), and operates in the 1.55- mu m wavelength region. Small device capacitance (0.2 pF) has been obtained by using spin-coated polyimides under the bonding pads, and small stray capacitance (0.07 pF) and bonding wide inductance (0.3 nH) have been realized. The modulator requires the lowest power yet reported for a high-frequency-operation external modulator.<>