Performance evaluation of optoelectronic oscillators

In the present work, we establish the importance of amplifier phase noise and system environmental fluctuations in determining the low-frequency (f<100 Hz) noise of the oscillator. The system, designed to be a low phase noise microwave oscillator, has a measured single-side-hand (SSB) phase noise of -123 dB/Hz (relative to 1 rad/sup 2//Hz) at 10 kHz from the 10.6 GHz carrier. The fractional frequency stability required for advanced atomic frequency standards is of the order of 10/sup -4///spl radic//spl tau/. This requirement might be met with an ideal version of this optoelectronic oscillator if we could reach the noise limit determined by the optical shot noise.