The effect of analog video modulation on laser clipping noise in optical video-distribution networks

Laser clipping distortion has been shown to cause potentially severe bit-error-rate (BER) floors in hybrid fiber/coax (HFC) networks carrying a combination of analog and digital video signals. Previous experimental investigations have generally used unmodulated analog carriers to quantify the effects of laser clipping. This paper provides experimental measurements of clipping noise and BER performance when the analog carriers are modulated, as they would be in actual systems. Comparisons with the case of unmodulated carriers are also given. Dramatic reductions in clipping-related degradation are observed once the carriers are modulated, suggesting that laser clipping will not pose a significant impediment to digital transmission in future HFC networks.