Optical phase conjugation for intra-channel nonlinearity compensation in 40 Gbit/s CSRZ pseudo-linear systems

The compensation of intra-channel nonlinear effects in a CSRZ 40 Gbit/s 32*100 km system using an LiNbO/sub 3/ optical phase conjugator in a re-entrant, recirculating loop architecture, is experimentally demonstrated. Two decades of improvement in the bit error rate at 3200 km with phase conjugation has been achieved. Also, the performance of CSRZ and RZ-DPSK modulation formats at 3200 km with and without optical phase conjugation is compared.