ASE-noise limit of direct-detection receivers: duobinary Vs. IMDD

摘要

The duobinary technique, at first proposed in the 60's for radio communications, has recently re-emerged in the field of optical communications as a possible candidate for next generation of Ultra-DWDM systems. The purpose of this work is to derive, for the first time to our knowledge, the back4o-back sensitivity (quantum limit) of duobinary technique in ASE-noise-limited direct-detected optical systems: we found that it is at least 0.91 dB better than the IMDD limit and we show that a practical duobinary system setup could closely approach the quantum limit.