Performance optimization for 44 Gb/s return-to-zero partial DPSK transceiver with pre-emphasized electrical signal driving path

Using a Karhunen-Loève series expansion (KLSE) based quasi-analytical method for BER calculation, we investigate performance optimization for 44 Gb/s return-to-zero (RZ) partial DPSK (PDPSK) transceiver with reduced component bandwidth, where the optimization is done by pre-emphasizing the gain shape of electrical signal driving path in the transmitter and varying the free spectral range (FSR) of the delay line interferometer (DLI) in the receiver. Both weak and strong optical filtering are studied, where the strong optical filtering case models long haul systems containing cascaded optical add drop multiplexers (OADMs). We found that with pre-emphasis and FSR as design degrees-of-freedom, the transceiver can tolerate more performance degradations for reduced transceiver bandwidth and strong optical filtering.