Reduction of Cavity Pulling in a Passive Hydrogen Maser

摘要

A new method for detection of the hydrogen resonance in a passive maser, has been tested and experimentally verified. This technique, which reduces the effect of cavity pulling on system performance, makes use of several amplitude and phase measurements of the combined transfer function associated with the cavity and hydrogen line. The atomic resonant frequency, determined in this way, has been shown to be essentially free from cavity pulling. For example, we have measured pulling factors 40 times lower than those measured using pure amplitude or phase techniques for the detection of the hydrogen resonance. The smaller cavity pulling factor is important in systems where cavity tuning errors are thought to yield an intrinsic limit on overall clock performance. The technique can be useful as a diagnostic tool, or as the hydrogen resonance detection method in an operational passive maser.