As the global telecommunications industry continues its transformation, we have been witnessing a steady stream of advances in all communications technologies from optical transport to access networks. However, worldwide attention to access network deployments with the entire global industry's concerted effort on standards compliant product development has been most notable. Although we very recently, in February 2011, devoted a special OFC/NFOEC '11 supplement to passive optical network (PON) advances, we have selected PONs as our theme again in this Optical Communications Series (OCS) issue in recognition of this continuing worldwide focus on PON technologies. Two excellent examples of this global focus on PONs are the gigabit PON (GPON) optical network unit (ONU) certification timetable announced by Broadband Forum at their third quarter 2011 meetings held in Shanghai, China, during the week of September 19, 2011, and the high level of participation at the FTTH Council Conference & Expo held in Orlando, Florida, dur ing the week of September 26, 2011. In this issue, we have selected three contributions that address 10 Gb/s Ethernet PON (10G-EPON) performance, dynamic spectrum management in existing PONs, and technology advances toward next-generation PONs (NG PONs).