Abstract
In recent years, optical duobinary transmission (DBT) system is very attractive because of its narrow spectral width and high chromatic dispersion tolerance. In linear regime, a 10 Gb/s optical duobinary signal can be transmitted over 200 km of standard single-mode fiber (SMF) without any compensation device. However, in the nonlinear regime with self-phase modulation (SPM), the improvement in dispersion tolerance of DBT decrease rapidly duo to SPM limit. In order to improve the SPM effect, the method is inducing the chirp signal to maintain the balance between SPM and dispersion effect but the traditional chirped duobinary transmission (CDBT) scheme has complex transmitter because of using two modulators. In this paper, we experimentally demonstrate a cost-effective phase-modulation duobinary modulation scheme for improving self-phase modulation (SPM) tolerance using a single modulator. Successful transmission over 230 km of standard single mode fiber (SSMF) was achieved without any power penalty.