64 Gb/s silicon QPSK modulator with single-drive push-pull traveling wave electrodes

We demonstrate a silicon QPSK modulator consisting of two nested Mach-Zehnder interferometers with 3.5 mm long traveling-wave electrodes. 64 Gb/s QPSK modulation is achieved with an EVM of 24.4% and power consumption of 7.1 pJ/bit.