A performance comparison of single-ended- and differential driving scheme at 64 Gbit/s QPSK modulation for InP-based IQ-Mach-Zehnder modulators in serial-push-pull configuration

We show the positive impact of differential driving on the optical QPSK signal performance. For the first time, an EVM of <6% at 32 GBd QPSK has been achieved for a low power InP-IQM design, enabling small form factor transmitters.