350 km Transmission of 15-Channel 256-QAM Signals

Abstract

The multiple 256-quadrature amplitude modulation (256-QAM) channels subcarrier multiplexed (SCM) lightwave transmission systems are considered as a promising technology to deliver video signals for longdistance transmission. In this paper, we built and demonstrated a directly modulated NTSC 256-QAM 15-channel long-distance transmission system using 1 256-QAM signal and 14 continuous-wave (CW) carriers to simulate 14 256-QAM signals. Compared with a conventional optically amplified video transmission system in a digital network, not only total transmission channels were increased, but also good video quality was obtained in our proposed system over a 350-km single-mode fiber (SMF) transmission.