21 Gb/s polarization switched-QPSK real-time coherent FPGA-based receiver

A real-time FPGA-based receiver of 21Gb/s PS-QPSK signal is reported and tested against optical noise, chromatic dispersion (CD), polarization mode dispersion (PMD) and state of polarization (SOP) scrambling. A comparison with PDM-QPSK realized with equivalent parameterized setup and signal processing confirm the greater tolerance of PS-QPSK over PDM-QPSK.