Monitoring of opto-electronic oscillator fiber delay by a probe-signal method

Opto-electronic oscillators (OEOs) are based on a long optical fiber that acts as a high Q cavity. However, a long fiber is sensitive to the temperature fluctuation. The aim of this paper is to study the possibility of stabilizing the OEO cavity by employing the technology of radio frequency transfer over fiber links. We propose a scheme of a dual-loop OEO with a probe signal and experimentally demonstrate that the probe signal is useful for monitoring the fiber delay without observable interference. This paper will simulate the adjusting of the OEO optical cavity by a variable optical delay module and discuss its best long-term stability.