title: High-Q whispering gallery traveling wave resonators for oscillator frequency stabilization.
abstract: Usually a frequency-stabilized standing wave resonator-oscillator incorporating a resonator as a frequency discriminator requires a circulator to separate the injected and reflected wave, A ferrite circulator is a noisy device and can limit the phase noise or frequency stability. Moreover, we show that the noise in a circulator varies, and detailed low noise measurements are necessary to choose an appropriate quiet circulator. Thus, by realizing a configuration that does not require a circulator, an improvement in performance and reliability can be obtained. A solution to this problem is to design a high-Q whispering gallery traveling wave (WGTW) resonator. This device naturally separates the injected and reflected wave in the same way as a ring cavity at optical frequencies, without degrading the frequency discrimination. Q-factor measurements of a WGTW sapphire resonator are presented, along with a derivation of critical parameters to maximize the frequency discrimination. New measurements of noise in ferrite circulators and isolators have also been made, which is followed with a discussion on oscillator design.
authors.affiliation: Dept. of Phys., Western Australia Univ., Nedlands, WA.
authors.forename: M E
authors.initials: ME
authors.lastname: Tobar
authors.forename: E N
authors.initials: EN
authors.lastname: Ivanov
authors.forename: P
authors.initials: P
authors.lastname: Blondy
authors.forename: D
authors.initials: D
authors.lastname: Cros
authors.forename: P
authors.initials: P
authors.lastname: Guillon