44 Gb/s PAM-4 Transmission with a Polarization- Independent Surface-Normal Electroabsorption Modulator

We measure performance of 44-Gb/s (22-GBd) PAM-4 short-reach direct detection links with a polarization-independent surface-normal electro-absorption modulator. Performance below the KP-4 FEC threshold is demonstrated in standard single-mode fiber links with no dispersion compensation for distances up to 18 km.