Ge p-i-n Photodiode as 60-Gbit/s Optical NRZ-OOK Data Receiver

作者：Jyun-Yang Su, Kuo-Fang Chung, Shih-Chun Kao, Chih‐Hsien Cheng, C.S. Tsai, Te‐Hua Liu, Hao-Tien Cheng, Chao‐Hsin Wu, Tien‐Tsorng Shih, Ding‐Wei Huang, Gong‐Ru Lin · 发表于：Journal of Lightwave Technology · 年份：2022 · DOI：10.1109/jlt.2022.3161011 · 被引用次数：14 · 研究领域：Photonic and Optical Devices、Advanced Photonic Communication Systems、Advanced Fiber Laser Technologies

By the pulsed, heterodyned, and modulated laser illuminations, the impulse and noise responses of O-band germanium (Ge) p-i-n waveguide photodetector (WPD) with different transmission-line designs are characterized for receiving the NRZ-OOK data beyond 60 Gbit/s. The Ge lateral p-i-n WPD reveals an optical responsivity of 0.63-0.74 A/W at 1327.5 nm under −1.8 V bias.The noise equivalent power (NEP) is increased from 0.11 to 0.2 pW/√Hz by shrinking the transmission-line contact electrode length from 280 to 80 μm. After optimizing the transmission-line designs with shorter length and less right corner number (C⊥#) between PD and bonding pad, the Ge lateral p-i-n WPD improves its RLC response to suppress its switching time with broadened receiving bandwidth. Shrinking the connecting transmission-line length from 280 μm to 80 μm extends the flattened S11spectral response from 51 to 57 GHz by up-shifting the inductor inductor-induced frequency notch from 58 to 61 GHz, as confirmed by the shrank spiral curve in the Smith chart with the decreased inductance by shortening the transmission-line electrode. The dual-wavelength optical heterodyne analysis demonstrates that the Ge p-i-n WPD significantly improves its analog receiving bandwidth from 29.5 to 44.3 GHz measured at 6-dB decay. The sub-ps laser pulse illumination observes that the Ge p-i-n WPD response shortens its impulse response from 23.14 to 19.92 ps by reducing the contact inductor length (by 200 μm) and right corner numbe...