OEOs With Carrier Suppression for Reduction of Phase Noise

Optoelectronic oscillators (OEOs) that incorporate carrier-suppression subsystems for reduction of close-to-carrier phase noise are undergoing development. The carrier-suppression phase-noise-reduction technique has previously been applied to microwave oscillators. The close-to-carrier phase noise in a microwave oscillator consists mainly of a component that is generated in an amplifier in the oscillator feedback loop and that has a spectral amplitude proportional to 1/f, where f is the difference between the frequency of interest and the carrier frequency. In the case of an OEO, one can use the carrier-suppression technique to reduce not only the component of phase noise generated in the amplifier but also the component of phase noise associated with laser relative-intensity noise.