Low-phase-noise frequency synthesizer based on optoelectronic oscillator

摘要

We design and investigate a frequency synthesizer for generating a serial of low-phase-noise frequencies from 5.9GHz to 12.9GHz using an optoelectronic oscillator (OEO) as the reference. The 10 GHz free-running OEO has an ultra-low phase noise of -136dBc/Hz at 10 kHz offset. The phase noise of the constructed frequency synthesizer at 10 kHz offset is from -135dBc/Hz to -125dBc/Hz. The spurious suppression ratio is more than 55dBc and the frequency hopping time is shorter than 1.5us for a 20-MHz frequency transition. The results verify that, OEO is a good candidate for the reference of a frequency synthesizer to achieve low phase noise frequencies.