Nonlinearity Mitigation of Multi-Level Optical Transmission Using Spectrum-Split Digital Pre-Distortion

Abstract

To overcome the frequency-dependent nonlinear characteristics of a directly modulated laser (DML) in a multi-level optical transmission, the spectrum-split digital pre-distortion (SS-DPD) is proposed and experimentally demonstrated to mitigate the frequency-dependent nonlinear impairments. The SS-DPD is employed in a 5 Gb/s PAM-4 optical transmission using a DML over a 5 km standard single-mode fiber at 1550 nm. We experimentally compared the SS-DPD with the DPDs based on the Volterra series and the memory polynomial (MP). The results demonstrate that the SS-DPD improved approximately 1 dB in terms of the receiver sensitivity compared with the MP-DPD. Moreover, the SS-DPD achieves 0.4 dB receiver sensitivity gain compared with the Volterra DPD.

Keywords

• Linearization techniques
• nonlinear distortion
• optical fiber communication
• predistortion.