Design of realisable optimum post-detection filters for high data-rate m-PAM systems with clock jitter tolerance

The continual increase in demand for extremely high data-rate systems spans the full range of network systems from local area networks to long-haul systems. While coherent optical systems dominate the long-haul market, there is significant interest in using simpler direct detection systems for application areas, where simplicity and lower-cost is a key driver. Pulse-amplitude modulation (PAM) is appropriate to consider as it enables the reduction of the channel symbol rate for a given data rate, without unduly increasing the complexity of the system. A route to the design of optimum post-detection filter for PAM systems is presented that offers significantly improved robustness to timing jitter, which is an impairment of increasing import as symbol rates are increased.