A Photon Detection System with Power and Signal over Fiber

The Deep Underground Neutrino Experiment (DUNE) is a long baseline neutrino experiment for neutrino science and Beyond the Standard Model physics. The experiment will make use of four far detector (FD) modules, 1300 km away from the beam line, installed 1.5 km deep underground. The FD modules will consist of Liquid Argon Time Projection Chambers (LArTPC) with 17 kt of liquid argon (LAr) each, the largest ever attempted.In December 2020, the DUNE Collaboration proposed the Vertical Drift (VD) LArTPC technology with the aim to instrument the second FD module. In the VD the Photon Detection System (PDS), will be placed in the cathode in order to optimize light collection. However, the fact that the cathode will be biased at −300 kV for DUNE excludes the possibility to supply power and read out the PDS signals with conductive wires. The proposed solution is to use Power-over-Fiber (PoF) and Signal-over-Fiber (SoF). In this work the powering and analog signal readout of SiPM photodetectors using laser light transmitted over optical fibers are described, with emphasis in the development of the cryogenic analog optical transmitter to be used for SoF transmission. Results will be shown from the recent demonstration of this solution made at the CERN neutrino platform.