Electronic post-compensation of optical fiber nonlinearity in high-speed long-haul wavelength division multiplexed transmission systems.

Abstract

A vast majority of optical fiber infrastructure deployed today utilizes 10 Gb/s transmission technology which is falling short of demands for current communication networks. To fulfill the ever increasing needs of bandwidth, the research trend since past few years has been in the direction of increasing the per channel data rate to ≥ 40 Gb/s. The transmission of optical pulses over ≥ 40 Gb/s data rates greatly suffers from degradations arising from interaction of dispersion and optical fiber nonlinearity. The work presented in this thesis focuses on the development and evaluation of a novel electronic signal processing technique that can undo the degradations already caused by the interaction between dispersion and intra-channel nonlinearities. The proposed technique tends to compensate degrading nonlinear effects by incorporating the knowledge of the neighboring bits and exploiting the fact that for a given bit pattern, the nonlinear degradation, deterministically, depends upon dispersion map and operating channel power. We have tested our proposed technique in WDM transmission systems using return-to-zero (RZ), carrier suppressed RZ (CSRZ) and differential phase-shift keying modulation formats, and have analyzed the system performance by using computer simulations. Our analysis shows that the proposed scheme can significantly undo the degradation caused by fiber nonlinearity and can significantly increase the overall system margin of a 40 Gb/s WDM system.