Spectrally Efficient Parallel PHY for 100GbE MAN and WAN [Applications & Practice]

The serial 100 GbE PHY (physical layer) based on advanced modulation techniques such as differential quadrature-phase- shifted-keying (DQPSK.) have been experimentally demonstrated by laboratories worldwide. This interface is envisioned for future ultra-long-haul systems. In this article, we present an alternative approach to 100 GbE transmission in a metropolitan-area network (MAN) and a wide-area network (WAN), which is based on parallel PHY. We discuss the advantages of this approach in comparison with the conventional serial PHY from both technical and economic points of view.