Bulk Undoped GaAs–AlGaAs Substrate-Removed Electrooptic Modulators With 3.7-V-cm Drive Voltage at 1.55 $\mu$ m

Substrate removed bulk GaAs-AlGaAs electrooptic modulators with 3.7-V-cm drive voltage at 1.55 mum were realized. The 1.94-mum-thick undoped GaAs-AlGaAs epilayer removed from its substrate behaves as an electrooptic dielectric layer and has electrodes placed directly on both sides. This allows a very strong modulating electric field overlapping very well with the optical mode. The propagation loss in the presence of electrodes is less than 2.9dB/cm. There is very good agreement between the measured and simulated values