SPM-Improved Transmission Performance of Software-Reconfigurable IMDD PONs Based on Digital Orthogonal Filtering

Extensive explorations are undertaken of the feasibility of utilizing self-phase modulation (SPM) to mitigate the channel fading effect associated with digital-orthogonal-filtering-enabled software-reconfigurable intensity-modulation direct-detection passive optical networks (PONs). A comprehensive theoretical model is developed and subsequently verified, based on which numerical simulations are undertaken to investigate the effectiveness of the effects of both SPM and adaptive channel power loading in maximizing the signal transmission capacity of each individual channel in the aforementioned PON systems. It is shown that, for the channel experiencing the worst channel fading effect, the SPM effect can enhance its transmission capacity by a factor as large as 2, and a further 45% transmission capacity improvement is also obtainable when adaptive channel power loading is applied. The signal transmission capacity improvement enabled by the coexistence of these two effects increases almost linearly with transmission distance. The research work not only provides a new means for dynamically manipulating the signal transmission capacity of each individual channel, but also allows the utilization of low-cost optical components without comprising the overall PON system performance.