Transmission and reception of PDM dual-subcarrier coherent 16QAM-OFDM signals

• Dual-subcarrier 16QAM-OFDM has lower PAPR compared to conventional OFDM signal.
• Dual-subcarrier 16QAM-OFDM can be retrieved like a 49QAM without any overhead.
• The minimum bandwidth requirement is discussed for dual-subcarrier 16QAM-OFDM.
• We achieve 100 Gbit/s dual-subcarrier OFDM signal transmission with 16QAM modulation format.

In this paper, 16-Gbaud polarization-division-multiplexed (PDM) dual-subcarrier coherent optical orthogonal frequency division multiplexing (CO-OFDM) transmission and reception are successfully demonstrated without overhead. The in-phase and quadrature (I/Q) components of dual-subcarrier 16-ary quadrature amplitude modulation (QAM) OFDM signal are both seven-level signals in time domain, and thus can be equalized like a 49 QAM signal in time domain with cascaded multi-modulus algorithm (CMMA) equalization method. The experimental results show that there is no power penalty observed between optical back to back (OBTB) and after 80-km single-mode fiber-28 (SMF-28) with time domain CMMA equalization method. A 0.4 dB optical signal to noise ratio (OSNR) penalty in OBTB is observed when the bandwidth of channel is set at 26 GHz at the BER of 2.0 × 10−2.