Versatile coherent in-line 4-, 16-, 32-QAM subcarrier add/drop-multiplexing by optical frequency conversion
We experimentally investigate the modulation format scalability & agility of a coherent add/drop node. Extinction of 25 dB yields OSNR penalties up to 1.1-dB for 3.2-GBd intra-format subcarrier add/drop up to 32QAM and 0.8-dB for inter-format 4QAM-by-16QAM add/drop.