224-Gb/s Carrier-recovery-free Doubly Differential 2ASK-8PSK for Short-reach Optical Networks

T. Zhang, C. Sanchez, M. Al-khateeb, A. Ali, M. Tan, P. Skvortcov, I. Phillips, S. Sygletos, A. Ellis

Research output: Contribution to journalArticlepeer-review


We propose and experimentally demonstrate a carrier-recovery-free 224-Gb/s dual-polarization doubly differential (DD) two-amplitude/eight-phase shift keyed (2ASK- 8PSK) signal for 100-km fiber transmission with coherent detection. An 11-tap multi-symbol DD (MSDD) decoding scheme helps reduce the penalty caused by two differential operations in conventional DD decoding, allowing an optical signal-to-noiseratio (OSNR) improvement of 3.7 dB for DD QPSK and 4.3 dB for DD 16QAM. By employing such decoding, a frequency offset (FO) tolerance of 16 GHz has been achieved in a DD 2ASK-8PSK system for a BER of ~1×10-3. Compared with a 224-Gb/s 16QAM system employing conventional carrier recovery algorithms, the proposed system is more robust to FOs, and the FO tolerance range is only limited by the effective receiver bandwidth.
Original languageEnglish
Pages (from-to)1463 - 1466
JournalIEEE Photonics Technology Letters
Issue number16
Early online date16 Jul 2018
Publication statusPublished - 15 Aug 2018

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