An Optimized Frequency Locking Loop Employing FM Spectroscopy for a CPT Based Atomic Clock

We present an experimental optimization of the frequency modulation spectroscopy parameters used for a locking loop of a CPT based atomic clock. The optimized operating conditions yield a feedback signal with the largest obtainable signal to noise ratio with which we achieve state of the art clock performance in a system employing a miniature glass Rubidium vapor cell.