Top-Illuminated Avalanche Photodiodes With Cascaded Multiplication Layers for High-Speed and Wide Dynamic Range Performance

• Published in: Journal of lightwave technology Vol. 40; no. 24; pp. 7893 - 7900
• Main Authors: Naseem, Wang, Po-Shun, Ahmad, Zohauddin, Parvez, Syed Hasan, Yang, Sean, Chen, H.-S., Chang, Hsiang-Szu, Huang, Jack Jia-Sheng, Shi, Jin-Wei
• Format: Journal Article
• Language: English
• Published: New York IEEE 15.12.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Avalanche diodes; Avalanche photodiode; Avalanche photodiodes; Bandwidth; Dark current; High speed; Indium phosphide; Optical receivers; Optical saturation; Optical sensors; p-i-n photodiode; Photodiodes; Saturation; Sensitivity enhancement
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2022.3204743

In this work, a novel top-illuminated avalanche photodiode (APD) with a In 0.52 Al 0.48 As multiplication (M-) layer is demonstrated. The cascaded M-layer design combined with the unique p-side up mesa structure allows relaxation of the fundamental trade-off between the gain-bandwidth product and the dark current. This leads to the simultaneous high-responsivity, high-speed, high-saturation-power, and low-dark current characteristics of our APDs. At around 0.9 V br operation, the demonstrated device with its simple top-illuminated structure and large active window (mesa) diameter of 14 (24) μm exhibits a high responsivity (2.23 A/W), wide optical-to-electrical bandwidth (30 GHz), large gain-bandwidth product (270 GHz), low dark current (∼200 nA), and a saturation current as high as 11 mA. The excellent performance of this APD structure opens up new possibilities to further enhance the sensitivity performance of receivers for coherent communications or 106 Gbit/sec PAM-4 applications.