Precoding-Enabled FBMC/OQAM for Short-Reach IMDD Transmission

Filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) can provide higher spectral efficiency and lower out-of-band spectral/power leakages than conventional orthogonal frequency-division multiplexing with QAM (OFDM/QAM). Due to the imperfect frequency response of electrical/optical devices and various interferences, significant subcarrier SNR fluctuation may result in poor bit error rate (BER) performance. In this work, channel-independent precoding techniques are employed for the short-reach FBMC/OQAM-based intensity-modulated and direct-detection (IMDD) system. Four commonly used precoding techniques are experimentally investigated in a directly-modulated laser-based IMDD FBMC/OQAM and OFDM/QAM systems over a 20-km fiber link. The relevant results exhibit that the receiver sensitivity of these two systems can be improved by about 2 dB with precoding techniques at the BER of 3.8e-3. A slight BER enhancement can also be achieved by the precoded FBMC/OQAM compared to the precoded OFDM/QAM.