Over 220 GHz evanescently coupled MUTC-PDs with enhanced responsivity

作者：Mingwei Sun, Bing Xiong, Changzheng Sun, Zhibiao Hao, Jian Wang, Lai Wang, Yanjun Han, Hongtao Li, Lin Gan, Yi Luo · 发表于：Optics Express · 年份：2025 · DOI：10.1364/oe.559249 · 被引用次数：5 · 研究领域：Photonic and Optical Devices、Radio Frequency Integrated Circuit Design、Advanced Photonic Communication Systems

We present evanescently coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) with ultra-wide bandwidth and high responsivity. What we believe to be a novel epitaxial structure incorporating a multilayer input waveguide is designed to enhance the light absorption efficiency. An optimized passivation scheme, on-chip matching resistors, and high-impedance CPW electrodes are introduced to improve the RC response. The fabricated 4 × 5 µm 2 PDs achieve a record responsivity of 0.56 A/W and a 3-dB bandwidth over 220 GHz, effectively overcoming the typical trade-off in high-speed PDs. Clear eye opening has been demonstrated for 280 Gb/s 4-level pulse amplitude modulation (PAM4), 330 Gb/s PAM6, and 384 Gb/s PAM8 signals.