Performance limits on M-QAM transmission in hybrid multichannel AM/QAM fiber optic systems

Performance limits on M-QAM transmission in hybrid multichannel AM/QAM (amplitude modulated/quadrature amplitude modulated) fiber-optic systems are presented. It has been shown that for such hybrid analog/digital transmission over an optical fiber, the induced in-band clipping noise will significantly degrade the reception performance of M-QAM signals. Here the author determines the channel capacity and signal power (or optical modulation index) of M-QAM as limited by the presence of the clipping noise, which is non-Gaussian and impulsive, and discusses design tradeoffs for M-QAM channels in such cases.<>