Low Noise L-band RF-over-fiber Signal Transport for ALPACA on the GBT

After the catastrophic failure of the Arecibo Tele-scope on Dec. 1, 2020, the intended host telescope for the 69-element wide-field phased array feed ALPACA instrument was lost. Design of the RF -over-fiber (RFoF) signal transport link to the FPGA/GPU digital beamformer back end was revisited to accommodate the physical and operating requirements of a new host telescope. The equivalent noise temperature of the link must be below 850 K in order for signal transport to contribute no more than 1 K to the target system noise temperature performance of 27 K for the instrument. We present progress of the new design and report on its performance.