Bias Circuit-Integrated DC-160 GHz Ultra-Broadband Photodetector for Advanced Optical Fiber Communication

With the rapid increase in data traffic within data center networks, the 100 Giga-bit Ethernet optical transceiver has become a critical component. According to IEEE P802.3df (beyond 400 Gb/s Ethernet), a roadmap has been established for developing a 1.6 Tbps pluggable transceiver [1]. Currently, a 400 GbE transceiver operates with a configuration of 100 Gbps per lane in a 4-lane (4-WDM) setup, while an 800 GbE transceiver can operate at 200 Gbps per lane with 4-WDM or 100 Gbps per lane with 8-WDM. For the 1.6 TbE transceiver, the data rates per lane are expected to reach 200 Gbps (8-WDM) to 400 Gbps (4-WDM). Thus, the data rates (symbols) per lane are expected to increase significantly to 200–400 Gbps in the near future. Recently, we studied an ultra-broadband photodetector (PD) device targeting a frequency response exceeding 200 GHz with an external bias circuit (a bias-tee circuit) [2]. Meanwhile, commercially available 0.8 mm coaxial connector extend the frequency response to 145 GHz, compared to 1.0 mm coaxial connector, which are limited to 110 GHz. In this study, we designed a bias circuit-integrated PD device capable of high-speed operation well above 145 GHz, assuming the implementation with a 0.8 mm coaxial connector in a PD module.