Long-Term Stable Optoelectronic Oscillator Based on Phase-Locked Loop

We demonstrate an optoelectronic oscillator (OEO) based on a phase-locked loop and an optical delay line to enhance its long-term stability. By detecting the phase of a single-frequency probe signal and compensating for the delay variation of the resonant cavity, a 10 GHz OEO is obtained with improved phase noise at the low offset frequency. The Allan deviation of OEO reaches 1.36E-15 at the average time of 400 s. The long-term stability of the OEO meets the strict requirements of applications in radar, signal processing, and precise measurements.