en.Wedoany.com Reported - Researchers at the University of Illinois Urbana-Champaign have demonstrated a high-speed cryogenic optical interconnect technology based on vertical-cavity surface-emitting lasers (VCSELs), which supports data rates up to 138 Gbps per channel while reducing thermal leakage and power consumption in infrared focal plane arrays (FPAs). The findings, published in IEEE Photonics Technology Letters, address a key challenge in next-generation cryogenic imaging systems, where traditional copper interconnects introduce unwanted heat to sensitive detectors.
Modern cryogenic FPAs continue to improve in resolution, sensitivity, and imaging speed, pushing total data rates beyond 100 Gbps. Conventional electrical interconnects require numerous copper connections that conduct heat into the cryogenic sensor assembly, increasing detector noise and cooling requirements. The research team evaluated VCSEL optical links operating at temperatures from 77 Kelvin (-196°C) to 120 Kelvin (-153°C), demonstrating modulation bandwidths exceeding 50 GHz at bias currents below 4 mA. These devices successfully transmitted 112 Gbps PAM-4 signals and extended per-channel rates to 138 Gbps, with TDECQ measurements of 3.42 dB at 77 K and 4.15 dB at 120 K, both within applicable IEEE short-reach multimode fiber communication specifications.
The researchers also estimated energy efficiency at approximately 68 femtojoules per bit at 77 K and 60 femtojoules per bit at 120 K, indicating that cryogenic VCSEL links can meet the bandwidth demands of advanced infrared imaging systems while reducing thermal load and power consumption. This study suggests that optical interconnects could become a practical alternative to copper interconnects for future cryogenic sensors used in defense, scientific instrumentation, astronomy, and other high-performance imaging applications.
"These results indicate that cryogenic VCSEL optical links can be a promising and cost-effective solution to meet the high-speed data communication needs of FPAs," said Liu.
