We report further progress on whispering gallery (WG) modes in a miniature temperature compensated composite dielectric sapphire and rutile resonator operating in a closed cycle cooler which can exhibit loaded Q/sub L/ values above 10/sup 7/ at /spl sim/10 GHz. The geometrical size of the dielectric pucks has been increased so that a compact loop-oscillator system is realized at a frequency close to the Cs atomic clock hyperfine frequency and an operating temperature of 63.5 K. Excellent long term temperature control (stability is better than 100 /spl mu/K) has been achieved. The high Q of the dielectric resonators can be used to produce low phase noise oscillators limited only by the performance of amplifiers and mixers. Effective mechanical vibration isolation is also demonstrated in a Giffard-McMahon cooler.
['Ling Hao', 'J.C. Gallop', 'N. Klein', 'Michael Winter']
Low phase noise temperature-compensated cryogenic whispering gallery mode resonator operated at 63 K in a closed cycle cooler