Beyond 100 Gbit/s PON: Flexible Rate and Coherent Architecture

In 2021, the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) developed the standards of 50 Gbit/s Passive Optical Network (PON). Currently, the equipment manufacturers and operators have completed prototype verification. ITU-T has established the Beyond 50 Gbit/s PON discussion group to explore future PON-related technical solutions. As a result, beyond 50 Gbit/s PON has become a research hotspot in the field of optical communication. According to the evolutionary pattern of previous PON standards, it is anticipated that the data rate of beyond 50 Gbit/s PON will exceed 100 Gbit/s. This article analyzes the problems and challenges faced by beyond 100 Gbit/s PON, focusing on two potential technological paths: flexible-rate PON and coherent PON architecture, along with their key technical solutions. This study provides references for future research and standardization of beyond100 Gbit/s PON.