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 LP
_0,1
and LP
_0,2
modes, 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.