Mode Division Multiplexing of Modes With the Same Azimuthal Index

The design of an SLM-based mode demultiplexer is discussed and mode division multiplexing is performed using the LP0,1and LP0,2modes, representing the first demonstration to propagate channels on modes with the same azimuthal index. Mode multiplexed transmission over 2 km of 50-μm OM2 fiber demonstrates a modal selectivity of 16 dB and an OSNR penalty of 1.5 dB for the transmission of 2 × 56 Gb/s QPSK signals.