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Polynomial-Time Complexity Large-Signal Model for DML-Based OOFDM Transmission Systems

The aim of this letter is to address the barrier imposed by the exponential-time complexity of current large-signal theory for calculating the chirp-induced distortions in short-range optical transmission systems using directly modulated lasers. This is a critical issue for modern optical orthogonal frequency division multiplexing signals with hundreds of subcarriers, especially for digital signal processing techniques intended to mitigate transmission impairments. A polynomial-time complexity model is proposed and its accuracy can be increased by including higher-order intermodulation products (IMPs). Signal-to-interference ratio differences between our analytical model and simulation results ~ 1 dB are achieved for taking into account IMPs up to fifth order.