25 Gb/s NRZ and 50 Gb/s PAM-4 Transimpedance Amplifier with Active Feedback and Equalization in 90 nm CMOS Technology Topics: High Speed Optical Lans and Gigabit Ethernet In Proceedings of the 16th International Joint Conference on e-Business and Telecommunications - Volume 1: OPTICS, 251-257, 2019 , Prague, Czech Republic