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.
Bibliographical noteFunding Information:
Manuscript received October 24, 2019; revised December 3, 2019; accepted December 6, 2019. Date of publication December 11, 2019; date of current version January 7, 2020. This work was supported by the Institute for Information and Communications Technology Promotion (IITP) under Grant 2019-0-00685, funded by the Korean government (MSIT) (Free space optical communication based vertical mobile network). Corresponding author: Sang-Kook Han (e-mail: firstname.lastname@example.org).
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering