Cryogenic all-sapphire optical-and-microwave flywheel oscillator

Microwave and optical oscillators both based on cryogenic sapphire resonators offer advantageous frequency stabilities over time intervals ranging from 0.1 to 10000 seconds. We present progress on the development of a combined optical-and-microwave oscillator, whose component optical and microwave resonators form the same physical package and, furthermore, whose resonance frequencies are defined by the same piece of mono-crystalline sapphire.