Ultimately phase-noise tolerant QPSK homodyne using a spectrum-sliced ASE light source

We experimentally demonstrated ultimately phase-noise tolerant 20-Gbps QPSK-homodyne transmission over 160km using a 3-nm spectrum-sliced ASE light source. We applied an optical phase noise cancellation technique based on self-homodyne detection using a polarization-multiplexed pilot-carrier, which included identical phase noise to that of modulated optical signal. BER of less than 1 × 10-6 after the transmission was achieved. We also characterized DGD and dispersion tolerances. To the author's best knowledge, this is the first experimental demonstration of multi-bit-per-symbol modulation/demodulation using an incoherent ASE light source.