Cryogenic Whispering Gallery Sapphire Oscillator for Microwave Frequency Standard Applications

摘要

A cryogenic Whispering Gallery sapphire resonator oscillator has been investigated using a 4 K pulse-tube cryocooler. The turnover temperature of the chosen mode in the sapphire crystal was 9.17 K with an unloaded Q-factor of 7 x10~8. The prototype sapphire-loaded cavity oscillator was designed to oscillate at 9.195 GHz. A fractional frequency stability of 2 x 10~(13) was measured at integration times of 10 s.