High- $Q$ Optoelectronic Oscillator Based on Active Recirculating Delay Line and Dual-Loop Topology

A high Q-factor optoelectronic oscillator (OEO) based on an active recirculating delay line and a dual-loop topology is proposed and demonstrated experimentally. The implemented OEO provides a very stable oscillation at 5.4 GHz with a sub-Hz 3-dB bandwidth and a Q-factor in excess of 10
¹⁰
. A single side-band phase noise of -74 dBc/Hz is measured at 10 kHz offset, while side modes are significantly suppressed for offset values in the range of 100 kHz-1 MHz.