Robustness of NRZ, RZ, CSRZ and CRZ modulation on fiber nonlinearities and amplifier noise at 40 Gbps for (OC-786) long haul link

In this paper, the robustness of NRZ, RZ, carrier-suppressed RZ (CSRZ) and chirped RZ (CRZ) modulation formats at 40 Gbps for (OC-786) long haul link on the amplifier noise figure and fiber nonlinearities has been investigated. The investigations reveals that highest Q2(dB) of the order of [20, 25]; [19, 20]; [18, 19] and [16, 18] has been obtained in case of RZ, CSRZ, CRZ and NRZ modulation formats, respectively, in the presence of fiber nonlinearities and with and without amplifier noise figure of 6 dB. It has been observed that Q2(dB) in case of CRZ fluctuate between 18 and 14 at power variation of −10 to 4 dBm and NF of 6 dB, while it is between 19–9, 20–0 and 16–0 in case of CSRZ, RZ and NRZ. It has been identified that CRZ and CSRZ have shown the robustness on fiber nonlinearity and noise at 40 Gbps up to the transmission distance of 450 km. The wide eye opening in case of CRZ modulation also proved the robustness on fiber nonlinearity and noise.