10 Gb/s duobinary receiver with a record sensitivity of 88 photons per bit

We demonstrate a novel receiver concept for duobinary signals that allows for data recovery with a sensitivity of -39.5 dBm (88 Photons/bit, BER=1.10/sup -9/, 2/sup 31/ -1 PRBS). Oversampling together with maximum likelihood sampling phase estimation results in superior back-to-back performance without lowering the large chromatic dispersion tolerance of duobinary signaling.