Reduced voltage substrate-removed gallium arsenide/aluminum gallium arsenide electro-optic modulators

Substrate removal techniques are successfully applied for the first time to Gallium Arsenide/Aluminum Gallium Arsenide electro-optic modulators in an effort to significantly reduce the drive voltage. Among other achievements, a capacitively loaded coplanar "T"-rail electrode is designed and tested for dispersion-free performance with a Mach-Zehnder GaAs/AlGaAs modulator resulting in a 3dB electrical bandwidth in excess of 40GHz at mu = 1.55mum. Key to the drive voltage reduction is the development of a substrate-removed version of the T-electrode as well as a fabrication first in low optical loss, substrate removed (SURE) semiconductor rib waveguides embedded in an organic polymer (BCB). The hybrid polymer/substrate-removed semiconductor waveguide modulator integrated with the substrate-removed version of the T-electrode leads to a drive voltage-length product of 8.7V---more than a factor of two reduction in drive voltage over previous designs and on par with current Lithium Niobate alternatives.