Data Transmission System for the Wideband Sensitivity Upgrade in Atacama Large Millimeter/submillimeter Array

Atacama Large Millimeter/submillimeter Array (ALMA) plans to upgrade its frontend and backend subsystem for the improvement of sensitivity to keep ALMA at forefront of scientific discovery. The upgrades mainly consist of wider correlated bandwidth by at least a factor of 2 and increased digital sensitivity using high-speed digitizer with 6-bit or more sampling. The Data Transmission System (DTS) plans to transmit such a large amount of data from antennas to 2nd generation correlator with optical network based on 400 Gigabit Ethernet (400GbE) technology. We present the conceptual design of the DTS upgrade and preliminary measurement results using 400 Gbps optical transceivers.