Efficient techniques for multi-gigabits/s transmission over plastic optical fiber

摘要

Due to their dispersive nature, large core step index plastic optical fibers (SI-POF) suffer from a bandwidth limitation. At high data rates or transmission distances, this leads to severe inter symbol interference (ISI). Efficient transmission techniques at the transmitter and robust equalization techniques at the receiver are needed to mitigate the effect of ISI. Discrete multitone transmission (DMT) is one of the most popular schemes to compensate dispersion in direct detection optical systems. Recently, non-linear equalization technique such as decision feedback equalization (DFE) and Tomlinson- Harashima precoding (THP) are being proposed for such dispersive channels. A possible low complex alternative to the such schemes can be a PAM block transmission with frequency domain equalization (PAM-FDE) at the receiver. This paper compares the bit loading enhanced DMT (namely asymmetrically clipped (AC) DMT) with systems employing nonlinear equalization techniques such as DFE and THP, and PAM-FDE for theoretical POF channels with a Gaussian profile. Although it is widely believed that non-linear equalization schemes will outperform the linear schemes such as PAM-FDE, we show that almost similar or better performance can be achieved by using PAM-FDE when system complexity is also taken into account.