Theoretical analysis of a hybrid AM-VSB/QAM SCM lightwave system with adjustable preclipping levels

A model for the analysis of the performance of a hybrid multichannel amplit ude modulation vestigal sideband (AM-VSB)/quadrature amplitude modulation ( QAM) subcarrier-multiplexed (SCM) lightwave transmission system with adjust able preclipping levels is presented. In the proposed model, two-stage adju stable clipping effect due to the preclipper and laser are considered, The analytical result shows that in this hybrid system the bit error rate (BER) is improved while the carrier-to-nonlinear distortion (C/NLD) ratio is deg raded as the value of the preclipping factor r is decreased, and vice versa , The validity of this model is verified by comparing the theoretical optim al value of r which is derived using our approach with the existed experime ntal result.