Recirculating fiberoptic link for memory loop

Fiber-optic links can be used as delay elements in microwave frequency memory loops. The authors present the analysis and experimental results of a recirculating memory loop operating over 2-4 GHz, leading to a 100 mu sec delay. The reactively matched optical transmitter and actively matched optical receiver are designed to achieve optimum loop performance. New gain equalization techniques are discussed which permit a long time delay in the range of milliseconds. The experimental results demonstrate recirculation of pulses at microwave frequencies in the range of sub-milliseconds. The analytical calculations indicate that, for a fiber-optic based memory loop, the total recirculation time for a flat frequency response reduces from 2300 to only 32 with a gain flatness of +or-1 dB, where a minimum 10 dB signal-to-noise ratio is specified.<>