[2] Diao X L. Wang Guang Quan: 5G and Cloud Put Forward Three Requirements for Optical Networks, and the Cost of Optical Modules Needs to be Reduced Urgently[J]. Communication World, 41(2018).

[3] Xiao L H, She L, Xu H C et al. 50 Gbit/s 40 km QSFP28 Transmission Module based on PAM4 Technology[J]. Study on Optical Communications, 51-54, 70(2019).

[4] Tao H W, Sun L P. Research on 100 G QSFP28 CWDM4 Optical Transmitting Component[J]. Electronic Design Engineering, 30, 92-96(2022).

[5] Chen C S, Lin T, Xu H C et al. Design of 50 Gbit/s BIDI Optical Module based on PAM4 Modulation[J]. Electronic Design Engineering, 28, 102-105, 110(2020).

[6] Chen J, Lu D C, Zheng X Q et al. A 50 Gbit/s PAM4 Externally Modulated Laser Driver Circuit[J]. Optical Communication Technology, 45, 10-13(2021).

[7] Zhou Y, Xiong J Q. Design and Optimization of 10 Gbit/s SFP+Optical Module Test Platform[J]. Measurement and Control Technology, 41, 64-69(2022).

[8] Xiao G, Ma H Y, Hu Y et al. A Low-cost PAM4 Signal BERT for 400 Gbit/s Optical Module Testing[J]. Optical Communication Technology, 45, 19-23(2021).