Frequency standard immune to laser wavelength variation and aging

Abstract

Embodiments herein describe peak detection techniques for selecting an absorption line to lock a spectroscopy laser in a frequency reference (e.g., an atomic clock). In one embodiment, an atomic reference is used which has many absorption lines within a relatively small frequency range (e.g., within a gain profile of the spectroscopy laser). The peak detection techniques can evaluate which of these lines a laser can be locked to. For example, the peak detection algorithm can define a preferred absorption line. But if for some reason the spectroscopy laser cannot be locked to the preferred absorption line, the peak detection technique has at least one backup absorption line. By having a set of candidate absorption lines, the peak detection algorithm can identify a suitable absorption line for lasers with different gain regions, or as gain regions change.