HIGH-PERFORMANCE MACH-ZEHNDER MODULATORS IN MULTIPLE-QUANTUM-WELL GAAS ALGAAS/

We demonstrate Mach-Zehnder interferometric waveguide intensity modula tors which employ electrorefraction due to the quantum-confined Stark effect in multiple quantum well (MQW) GaAs/AlGaAs. These devices exhib it average haff-wave voltage-length products as low as 3.0 V . mm and extinction ratios greater than 23.8 dB, which are superior to any MQW devices of this type. An effective index based model is developed to e xtract linear and quadratic electro-optic coefficients from the modula tion data. Also, the power handling limitations of MQW modulators are discussed in terms of device performance and catastrophic electrical f ailure.