ONU-Dependent Dispersion Pre-Compensation at OLT for High-Speed Wide-Coverage PON

We present the use of electronic dispersion pre-compensation at optical line terminals (OLTs) to increase the data rate as well as geographic coverage of passive optical networks (PONs). In time-division multiplexed PONs, the dispersion pre-compensation is made adaptive such that the signal blocks intended for different optical network units (ONUs) are compensated differently, based on the actual dispersions experienced by these signal blocks. We perform numerical simulations to show reach increase in 10-Gb/s PON based on on-off-keying (OOK), as well as data rate increase in 40-Gb/s PON based on high spectral efficiency formats such as pulse-amplitude modulation (PAM) and discrete multi-tone (DMT). All these formats are received by simple direct-detection (DD) receivers, aiming to keep the ONU cost-effective. Furthermore, we propose a novel optical transmitter design based on in-phase/quadrature (IQ) modulation in combination with a continuous wave branch to efficiently generate dispersion pre-compensated optical signals that are suitable for DD receivers.