Cryogenic sapphire microwave oscillators for space, metrology and scientific applications

Abstract

International audienceWe recently demonstrated a Cryogenic Sapphire Oscillator (CSO) presenting a short term frequency stability better than 3 × 10-15 for 1 s≤ τ <; 1000 s and achieving 4.5 × 10-15 for one day integration. This CSO incorporates a pulse-tube cooler instead of a bath cryostat-thus eliminating the need for regular supplies and manual transferring of liquid helium. The advent of reliable and cryocooled CSO open the possibility to implement such an ultra-stable reference not only in metrological laboratories with liquid helium facilities but also in remote sites like base stations for space navigation, VBLI antenna sites, ..

ULISS project: First comparison of two cryocooled sapphire oscillators at the 10^&#x2212;15 level

“…It incorporates a pulse-tube cryocooler instead of a bath cryostat, thus eliminating the need for regular supplies and manual refilling of liquid helium. The advent of reliable and cryocooled CSO open the possibility to implement such an ultra-stable reference not only in metrological laboratories with liquid helium facilities but also in remote sites like base stations for space navigation, VBLI antenna sites, ... [3], [4] In our project ULISS (Ultra Low Instability Signal Source), funded by Regional and European Institutions, we built a new cryocooled oscillator named ULISS specially designed to be transportable. The ULISS oscillator was already used to qualify with success a high stability frequency source located at Neuchâtel, Switzerland, and the PHARAO frequency synthesis Toulouse, France.…”