Optimized Pulse Shaping for Mitigating Optical Nonlinearity

Application of a digital non-linear compensation algorithm for evaluating the performance of root-raised-cosine pulses in 112 Gbit s−1DP-QPSK transmission

“…The waveform of the transmitted pulses is usually changed before sending it into the channel. This process is done to limit the effective bandwidth of the transmission and have a better control over the inter-symbol interference caused by the channel [22][23][24]. In order to have the non-ISI pulse system, two conditions must be fulfilled as: (a) pulse shape must exhibit a zero crossing at the sampling point of all pulse intervals and (b) the shape of the pulses must be such that the amplitude decays rapidly outside of the pulse interval.…”

“…The RC frequency transfer function is usually split between the transmitter and the receiver and the pulse shaping is realized by the root-raised-cosine (RRC) filter. The first RRC acts as the transmitting filter (band-limiting the signal launched into the channel) and the second RRC filter at the receiver completes the symbol shaping and also minimizes the effect of noise [22,23]. The combination response of two RRC filters is that of an RC filter.…”

“…The results depict 18%-25% improvement in the transmission distance when RZ pulse shapes are used. In recent articles [22][23][24] Inter-Symbol Interference (ISI) free pulse shaping, i.e. raised cosine (RC), has been investigated in 40 and 100 Gbit s −1 transmission systems with coherent receivers and post-compensated fiber links.…”