传统的光接入网速率已经无法满足快速增长的互联网流量需求。文章针对当前无源光接入网的发展状况，重点介绍了单波长25 Gbit/s光接入、单波长50 Gbit/s光接入和相干光接入这三种光接入网速率升级的主流技术，分析了其各自的优缺点，并介绍了我们研发团队在这些方面取得的部分进展。

Traditional optical access network cannot satisfy the fast capacity increasing requirements in current Internet. In this paper, considering the development of Passive Optical Network (PON) technologies in Optical Access Networks (OANs), we introduce three mainstream technologies to upgrade the capacity in OANs to achieve single-wavelength 25 Gbit/s transmission, single-wavelength 50 Gbit/s transmission and coherent optical detection. Both the advantages and disadvantages of the three technologies are analyzed. We also briefly introduce our work in these three areas.