High-Q optoelectronic oscillator using an active UR recirculating delay line

A dual-loop OEO using a SOA-based RDL is presented. The active loop creates a high Q-factor whilst the dual-loop suppresses side-modes. The OEO operates in the incoherent regime and in a proof-of-principle experiment produces a very stable 5.38 GHz oscillation with a Q-factor of 10
¹⁰
.