  An optical link system is being developed for the ATLAS Liquid Argon
Calorimeter Phase-II upgrade. The optical link system is responsible for
transmit the data of over 182 thousand detector channels from 1524 Front-End
Boards (FEBs) through 26 optical fibers per FEB over 150 meters to the counting
room and brings clocks, bunch crossing reset signals and slow
control/monitoring signals back to the FEBs. The optical link system is based
on the Low-Power GigaBit Transceivers (lpGBTs) and the Versatile optical
Transceiver (VTRx+) modules, which both are being developed for the
High-Luminosity LHC upgrade. An evaluation board is designed and the major
functions of the optical link system are being evaluated. The design of the
optical link system and the evaluation of major functions are presented in the
paper.
