Design and Studies of an Ultra High-Performance Physics Package for Vapor-Cell Rubidium Atomic Clock

This article introduces the development status of an ultra high-performance physics package (PP) for rubidium atomic clock. In order to increase the number of atoms participating in the resonance transition and enhance the atomic transition signal, we have appropriately increased the size of the PP. At the same time, we also have improved and optimized the microwave cavity, spectral lamp, filter components and the overall PP structure. And a new physics package with a Φ40 mm microwave cavity has been designed. We have conducted a comprehensive experimental research and theoretical analysis on the PP. Based on the measured PP parameters, we have evaluated that the contribution of the shot noise of the PP to frequency stability is 5.1 × 10⁻¹⁴τ^−1/2. Preliminary test results suggest that the rubidium atomic clock with this new PP can reach the short-term frequency stability of 1.5 × 10⁻¹³τ^−1/2 (1–100 s). This is the best short-term frequency stability of the lamp pumped vapor-cell rubidium atomic clock reported at home and abroad up to now, and the result is equivalent to the performance of the highest level laser pumped rubidium clock.