[1] [1] ITU-T. 40Gigabit-capable passive optical networks (NG-PON2): Definitions, abbreviations and acronyms: ITU-T G.989: 2015[S]. Geneva: ITU-T.

[2] [2] IEEE. 50G-EPON Task Force, Physical layer specifications and management parameters for 25 Gb/s and 50 Gb/s passive optical networks: IEEE P802.3ca: 2018[S/OL]. [2019-08-06]. http: //www.ieee802.org/3/ca/.

[3] [3] HARSTEAD E, VEEN D V, HOUTSMA V, et al. Technology Roadmap for Time-Division Multiplexed Passive Optical Networks (TDM PONs)[J]. Journal of Lightwave Technology, 2019, 37(2): 657-664.

[4] [4] VEEN D V, HOUTSMA V. Proposals for cost-effectively upgrading passive optical networks to a 25G line rate[J]. Journal of Lightwave Technology, 2017, 35(6): 1180-1187.

[6] [6] TAO M, ZHOU L, ZENG H, et al. 50Gb/s/λ TDM-PON based on 10G DML and 10G APD supporting PR10 link loss budget after 20km downstream transmission in the O-band[C]//Optical Fiber Communication Conference, March 19-23, 2017, Los Angeles, USA. Los Angeles: Optical Society of America, 2017: Tu3G.2.