In 2021,the International Telecommunication Union Telecommunication Standardization Sector(ITU-T)has devel-oped the standards of 50 Gbit/s Passive Optical Network(PON).Recently,the equipment manufacturers and operators have completed prototype verification.Nowadays,ITU-T establishes the Beyond 50 Gbit/s PON discussion group to start discus-sing future PON-related technical solutions Beyond 50 Gbit/s PON has become a research hotspot in the field of optical com-munication.According to the evolutional law of the previous PON standards,the data rate of Beyond 50 Gbit/s PON will be higher than 100 Gbit/s.This article will analyze the problems and challenges faced by 100 Gbit/s PON,focusing on two poten-tial technological paths:flexible-rate PON and coherent PON architecture,and their key technical solutions,providing refer-ences for future research and standard of 100 Gbit/s PON.