A hybrid photonic-integrated electroabsorption modulator device for 50-Gb/s DQPSK generation

We report a compact hybrid photonic-integrated optical device consisting of AlGaInAs/InP electroabsorption modulators and a four-arm silica-on-silicon planar lightwave circuit optical interferometer. We use the device to generate 50-Gb/s NRZ-DQPSK signal with excellent performances comparable to those of the commercial lithium niobate DQPSK modulators, while requiring only 2.5V pp drive signals.