Patent ID: 7580630
Filing Date: 2009-08-25
Classification: H04B

Abstract:
1. A transmitter for an optical transmission system arranged to transmit onto an optical transmission path, an optical sub carrier multiplexed signal comprising a number of sub-carriers in a band, the optical transmission path having impairments causing inter-subcarrier nonlinear interactions due to the Kerr effect in the path, and thus causing differing error rates for different ones of the sub-carriers, the error rates contributing to an aggregate error rate for the band, and the transmitter being arranged to selectively differentiate the sub-carriers to compensate differences between the contributions to the aggregate error rate caused by the inter-subcarrier nonlinear interactions due to the Kerr effect, wherein the sub-carrier output profile, which profile comprises the combination of the individual output profiles of said sub-carriers of said band, is non-uniform in amplitude or spacing or modulation scheme employed.