Analysis and Design of High-Performance Coherent Population Trapping Passive Atomic Clock System Based on Vertical-Cavity Surface-Emitting Laser

Based on the model of the Λ-type three-level atomic system, the principle, the evolutionary equations and the resonance line characteristics of the coherent population trapping (CPT) are analyzed by means of ensemble-averaged density matrix approach. The paper presents a schematic illustration of practical realization and a block scheme of comprehensive analysis of the CPT system. Using vertical-cavity surface-emitting laser (VCSEL) as optical source, we propose an appropriate physics package and design a small and digital servo circuit system, forming a subminiature adjustable and measurable CPT atomic clock system. The whole system is compact, small, low-power and well-adapted, in line with the further requirements of commercial development.