Techniques, devices and systems that stabilize an RF oscillator by using an optical resonator that is stabilized relative to a master RF oscillator with acceptable frequency stability performance. In the examples described, the optical resonator is stabilized relative to the master RF oscillator by using a frequency stability indicator based on two different optical modes of the optical resonator. The RF oscillator to be stabilized is then locked to the stabilized optical resonator to achieve the acceptable RF stability in the RF oscillator.