Title :
Power stabilized cryogenic sapphire oscillator
Author :
Luiten, A.N. ; Mann, A.G. ; Costa, M.E. ; Blair, D.G.
Author_Institution :
Dept. of Phys., Western Australia Univ., Nedlands, WA, Australia
fDate :
4/1/1995 12:00:00 AM
Abstract :
Microwave oscillators of exceptional short-term stability have been realized from cryogenic sapphire resonators with loaded Q factors in excess of 109 at 11.9 GHz and 6 K. This has been achieved by a power stabilized loop oscillator with active Pound frequency stabilization. These oscillators have exhibited a fractional frequency stability of 3-4×10-15 for integration times from 0.3 to 100 s. The relative drift of these two oscillators over one day is a few times 10-13. To reduce the long-term drift, which is principally due to excessive room temperature sensitivity, we have added cryogenic sensors for the power and frequency stabilization servos to one of these oscillators. We have also implemented a servo to reduce the room temperature sensitivity of our phase modulators. Testing of this oscillator against a Shanghai Observatory H-maser has shown an Allan deviation of 4×10-15 from 600 to 2000 s
Keywords :
cryogenic electronics; frequency stability; measurement standards; microwave oscillators; random noise; sapphire; servomechanisms; superconducting cavity resonators; 0.3 to 100 s; 11.9 GHz; 6 K; Al2O3; Allan deviation; H-maser; Shanghai Observatory; active Pound frequency stabilization; cryogenic sapphire oscillator; cryogenic sensors; fractional frequency stability; frequency stabilization servos; integration times; loaded Q factors; long-term drift; microwave oscillators; phase modulators; power stabilization servos; power stabilized oscillator; relative drift; room temperature sensitivity; Cryogenics; Frequency; Microwave oscillators; Observatories; Phase modulation; Q factor; Servomechanisms; Stability; Temperature sensors; Testing;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
