PRACTICAL TV CHANNEL CAPACITY OF LIGHTWAVE MULTICHANNEL AM-SCM SYSTEMS LIMITED BY THE THRESHOLD NONLINEARITY OF LASER-DIODES

Experimental measurements of clipping-induced nonlinear distortion due to over modulation of laser diodes in multichannel AM SCM systems are shown to be in good agreement with recent theory and simulation results. These results are then used to show that the number of channels, consistent with CATV distortion and noise requirements in presence of threshold nonlinearity, relative intensity noise, and receiver thermal noise, are higher than previous estimates. The sensitivity of these results with respect to the carrier-to-noise ratio requirement and the received optical power at the photodetector is also discussed.