112-Gb/s C-band transmission using 4-level/7-level coding PAM with chromatic-dispersion pre-compensation under 25-GHz bandwidth-limitation

We experimentally demonstrate 112-Gb/s 4-level/7-level coding PAM C-band transmission using pre-compensation under 25-GHz bandwidth limitation in a conventional direct-detection system. We confirm the scheme has higher residual-CD tolerance and requires fewer receiver-side FFE taps.