DD-OFDM transmission over few-mode fiber based on direct vector mode multiplexing.

The fiber vector eigenmode based mode division multiplexing (VMDM) transmission over few-mode fiber (FMF) with the 1st-order cylinder vector beams (CVBs) has been demonstrated. The performances of generated CVB using q-plate (QP) have been characterized before and after transmission over the FMF respectively based on the high-order Poincaré sphere model and polarization grating (PG). The measured minimum mode isolations between the two CVBs (TM01 and TE01 modes) of the used 4-mode FMF are about 16.8 dB after transmitting over 5 m and 12.5 dB over 100 m respectively. Then the dual-vector-mode-multiplexed transmissions over FMF of 96 Gb/s with length of 5m and 48 Gb/s of 100 m have been realized in combination with the modulation of direct-detection (DD) orthogonal-frequency-division-multiplexing (OFDM) without using multiple-input multiple-output (MIMO) digital signal processing (DSP). The experimental results indicate that the CVB-based technology could find the potential in large-capacity short-reach optical interconnects.