An alternative for the implementation of 40-km reach Ethernet at 400 Gb/s using an 8×50 Gb/s PHY at 1310 nm with SOA pre-amplification

The proposal and technical feasibility of a wavelength-division multiplexed system consisting of eight optical channels, each transporting data at 50 Gb/s in NRZ modulation format, are presented. It is numerically demonstrated that, aided by a semiconductor optical pre-amplifier with 23 dB of gain and setting the laser output power of an electro-absorption-based transmitter to +7.9 dBm, a propagation distance of 40 km over conventional single-mode optical fiber can be achieved with a BER < 1×10−13. Despite its high sensitivity, dispersion power penalty is minimized by setting a 400 GHz channel plan in O-band whose center is slightly red-shifted from the zero-dispersion wavelength of the fiber. Moreover, non-zero dispersion is found to be useful in reducing the deleterious amplifier nonlinear gain modulation at mid-range distances, whereas four-wave mixing is found to play a practically inconsequential role. In agreement with previous results derived for 25 Gb/s multi-channel links, optical signal-to-noise ratio degradation becomes the prominent corrupting factor at long fiber span lengths. The proposed architecture thus represents an alternative for the implementation of the physical layer of next-generation Ethernet or similar metropolitan data networks.