Broadband hybrid analog/digital CATV trunk network

In this paper, digital signals are externally intensity modulated in a wideband SONET format together with analog TV signals by using subcarrier multiplexing techniques. We also employ OAs (optical amplifiers) to amplify the signals in this trunk network to increase transmission distance. According to our result, the C-NR of the analog channels is larger than 49.5 dB and the BER of the SONET digital channel is less than 10/sup -9/ at the receivers of all headends. In this system, the 3rd order nonlinear distortions have been taken into account. We present a method to analyze the 3rd order nonlinear distortions.