Impact of fiber delay fluctuation on reference injection-locked optoelectronic oscillators.

We demonstrate that the phase shift of a reference injection-locked optoelectronic oscillator (OEO) varies as the change of its fiber delay over a long period of time. The dynamic variation of the fiber delay is monitored using an injected probe signal and is compared with the phase shift. With actively stabilized fiber delays according to the monitored data, the long-term frequency stability of the reference injection-locked OEO is evaluated.