Experimental Demonstration of Constant-Envelope OFDM to Reduce Intermodulation Impairments and Increase Robustness Against Fiber Nonlinearities

Direct detection optical orthogonal frequency division multiplexing (DDO-OFDM) systems have been proposed as a well-suited solution for cost-sensitive applications, but also metro/regional links. In this article, we experimentally demonstrate tolerance enhancements of constant-envelope OFDM (CE-OFDM) signals towards Mach–Zehnder modulator (MZM) intermodulation impairments and fiber nonlinear Kerr effects. The additional is achieved by the reduced peak-to-average power ratio (PAPR) CE-OFDM signals, unlike conventional that inherently possess high PAPR values therefore, are prone to distortions induced above-mentioned impairments. experiments show transmission with $=3$ dB over 1000 km dispersion-uncompensated standard single-mode (SSMF) successfully accomplished. proper choice MZM bias point, well electrical phase modulation index, provides link length enlargements at same bit error rate. An enlargement around 320 SSMF was an launch 10 dBm guard-band notation="LaTeX">$\approx 16\%$ signal bandwidth when compared DDO-OFDM systems.