Photonic Radio Frequency Memory Using Frequency Shifting Recirculating Delay Line Structure

A new structure for storing a radio frequency (RF) signal utilising a fibre-optic delay line is presented. It is based on a frequency shifting recirculating delay line loop for the RF pulse storage, which prevents lasing and enables multiple recirculations and long storage time to be realised. The new photonic RF memory (PRFM) can realise a long reconfigurable storage time, wide instantaneous bandwidth and high dynamic range. Experimental demonstration of the frequency shifting loop based PRFM has been carried out for the first time, showing a long and reconfigurable storage time of more than 300 μs with high signal fidelity.