Immunization of WDM systems to nonlinearity-induced crosstalk using optical polarization-shift-keying

We experimentally demonstrate the enhanced suppression of nonlinearity-induced crosstalk using polarization-shift-keying (PolSK) to guarantee constant optical power in a data stream. In a 40-km of LEAF link, PolSK has a 5 times lower nonlinearity-induced crosstalk level in a co-propagating channel with the channel spacing of 100 GHz than return-to-zero (RZ) modulation format. We reduce nonlinearity-induced power penalties by more than 4.6 dB compared with non-return-to-zero (NRZ), and 2.5 dB compared with RZ over the same fiber link at 10 Gbit/s.