Mitigation of Gain Fluctuations in Radio-over-Fiber Links within Large Radioastronomic Arrays

Radio over Fiber (RoF) constitutes the appropriate technology when the connections to the Remote Processing Facility of Large Radioastronomic Antenna Arrays have to be realized, particularly when the habitat exhibits extreme environmental conditions combined with a lack of infrastructures.Within such context, part of the electronics of the receiving chain must necessarily be located outdoors, and fluctuations of the link gain then are likely to appear, which in turn risk to impair the operations of beamforming referred to the weak sky signals.In the present work, some mitigation techniques aiming to minimize these fluctuations will be illustrated, which have been already adopted, or are under consideration for implementation, within the Low Frequency radiotelescope of the Square Kilometre Array (SKA-Low).