Fig. 1. Principle of coherent optical interconnection system employing SDM. (a) Principle of SDM; (b) effect of bandwidth limiting effect on signals of the same effective rate; (c) principle of De-SDM

Fig. 2. EXIT chart for SDM demapping and decoding

Fig. 3. Principle of experiment setup for coherent optical interconnection system employing SDM

Fig. 4. PDF of LLR in iterative De-SDM and LDPC decoding

Fig. 5. BER performance versus De-SDM iteration

Fig. 6. Received signal constellations. (a) 67 GBaud SDM-16 QAM; (b) 67 GBaud 32 QAM; (c) 84 GBaud 16 QAM

Fig. 7. BER performance of 400 Gbit/s coherent optical interconnection employing SDM-16 QAM