A Compact Laser System for the Pulsed Optically Pumped Rubidium Cell Atomic Clock.

We describe the design and implementation of a compact laser system for the pulsed optically pumped (POP) rubidium (Rb) cell atomic clock. The laser system includes packaged optics for sub-Doppler absorption, acousto-optic modulation and light beam expansion, and dedicated electronics for laser diode reliable single-mode operation and laser frequency stabilization. With beat measurements between two identical laser systems, the laser frequency stability was found to be ${3.0}\times {10}^{-{12}}$ for averaging times from 1 to 60 s and it reached ${3.5}\times {10}^{-{12}}$ at 10 000 s averaging time. Based on the compact laser system, the short-term stability of the Rb cell atomic clock in pulsed regime was approximately ${2.7}\times {10}^{-{13}}\,\, {\tau }^{-\text {1/2}}$ , which is in reasonable agreement with the estimated ${2.37}\times {10}^{-{13}}\,\, {\tau } ^{-\text {1/2}}$. The compact laser system is significant in terms of the development of transportable and high-performance Rb atomic clock prototypes. [ABSTRACT FROM AUTHOR]