Fiber-wireless transmission system of PDM-MIMO-OFDM at 100 GHz frequency

We experimentally demonstrated a seamlessly integrated fiber-wireless system that delivers 30.67-Gb/s polarization division multiplexing-multiple input multiple output-orthogonal frequency division multiplexing (PDM-MIMO-OFDM) signal through 40-km fiber and 5-m wireless transmission over free-space at 100 GHz adopting heterodyne coherent detection. De-multiplexing is realized by channel estimation based on a pair of time-interleaved training sequences (TSs). The bit-error ratio (BER) for the 30.67-Gb/s PDM-MIMO-OFDM signal is less than the pre-forward-error-correction (pre-FEC) threshold of 3.8 × 10 ^-3 when the optical signal-to-noise ratio (OSNR) is larger than 19.3 dB after both 40-km single-mode fiber-28 (SMF-28) transmission and 5-m wireless delivery at 100 GHz. We also find that the BER performance is sensitive to the multipath effects induced by the transmission distance difference in the wireless link.