Widely Tunable Regenerative Talbot Laser

The generation of tunable RF signals at high frequencies (> GHz) with low phase noise is crucial for telecommunication systems, broadband analog-to-digital conversions and RADAR systems. Recently, Frequency-Shifted Feedback (FSF) cavities seeded by a CW laser' so-called Talbot lasers' have been proposed to generate pulse trains with a repetition rate adjustable over orders of magnitude (up to tens of GHz), while being based on a low frequency RF synthesizer [1]. However, as such, due to the detrimental effects of amplified spontaneous emission, the phase noise performances of Talbot lasers are relatively poor. Here, we introduce a Talbot laser with a RF feedback inspired by coupled optoelectronic oscillators [2]. The regenerative RF loop allows operating the Talbot laser beyond threshold, by modulating the losses inside the optical cavity at the Talbot frequency. The purity of the generated signal is greatly improved, while preserving the FSF broad tuning capability at high frequency.