Physical layer aspects of NG-PON2 standards—Part 1: Optical link design [Invited]

NG-PON2 is the industry's first multiple wavelength (per direction), standards-based passive optical network system that is compatible with power-split optical distribution networks. The physical media dependent layer recommendation (ITU-T G.989.2) is the result of over three years of collaborative work by members of the FSAN and ITU-T Study Group 15, Question 2 groups. This two-part paper provides the technical insight and rationales behind the recently approved standard. The first part of the paper focuses on optical link design topics, including the optical distribution network characteristics, wavelength plan, Raman fiber nonlinearity related degradation, and interchannel cross-talk tolerance. It also describes the wavelength-tuning capability of optical network units and its impact on the physical media dependent layer specification.