Influence of Lamp Spectral Profile on Short-Term Stability and Light Shift of a Rubidium Atomic Clock

Passive gas-cell rubidium atomic clock has been widely used in Global Navigation Satellite System (GNSS). Further improvement on the frequency stability of rubidium atomic clocks has extreme significance for promoting the positioning and timing precision of GNSS. Distortion of the lamp spectral profile, caused by self-absorption, is a common concern for the design of a rubidium clock. However, few literature has systematically investigated the impact of lamp spectral profile on a Rb clock. In this work, the influence of lamp spectral profile on both short-term frequency stability and light shift of a rubidium clock was studied theoretically and experimentally. The results showed that serious distortion of the lamp spectral profile could lead to one times deterioration to short-term frequency stability, and change the zero light shift point by a few degrees centigrade. Thus, we demonstrated that optimization of the lamp profile may be an effective way to improve the performance of a Rb clock, which should be paid more attention when designing a high performance spaceborne Rb clock.