Research on photonic RF memory technology with large storage capability

Abstract

In order to overcome the bottleneck of digital radio-frequency (RF) memory such as narrow instantaneous bandwidth and low analogue-digital conversion rate, photonic RF memory technology with broad instantaneous bandwidth and fast response capability has been developed. In this paper, RF memory structure based on active recirculating loop with depth and high stable signal-to-noise ratio(SNR) is proposed and experimentally verified, which can meet the requirements of bandwidth and response speed in current RF storage field. This structure combines the active optical switch with the fiber delay-loop-based structure, which greatly increases the storage duration, suppresses out-of-pulse noise and improves the SNR while ensuring the ultralow loss of the photonic loop. The structure realizes RF storage with real-time response in 2- 18GHz frequency spectrum and pulse replication times is more than 360(equal to 18μs delay time), the average level of SNR is 20dB and its fluctuation over time is less than 1.5dB, which can be applied to different applications where broad transient bandwidth storage with long time delay is needed.