Abstract
This paper reviews the recent progress in high-speed optical line coding for future photonic transport network. We proposed the novel return-to-zero (RZ) line coding schemes that use carrier-suppressed return-to-zero (CS-RZ) pulse generation in both intensity-modulation and direct detection (IM-DD) system and differential phase shift keying (DPSK) system for the purpose of the modulation bandwidth reduction and the enhancement of fiber-nonlinearity tolerance in the long-haul dense wavelength division multiplexing (DWDM) transmission. The large tolerance of these formats against several fiber non-linearities and their wide dispersion tolerance characteristics are confirmed at the channel rate of 43 Gbit/s with 100 GHz spacing. The novel idea of duobinary modes splitting in DPSK spectral structure are proposed to understand the advantage of novel CS-RZ DPSK format concerning the strong spectral filtering and chromatic dispersion across the photonic transport network.
