The pulsed rubidium clock

In this paper, we describe a laboratory proto-type of pulsed optically pumped clock based on a rubidium vapor cell with buffer gas. The measured frequency stability (overlapping Allan deviation) is /spl sigma//sub y/(/spl tau/) = 3 /spl times/ 10/sup -12/ /spl tau/ /sup -/1/2 and the level of 4 /spl times/ 10/sup -14/ is reached for averaging time of /spl tau/ = 3 /spl times/ 10/sup 4/ s. For the same set of data, the statistical tool Theol predicts a frequency stability of 2 /spl times/ 10/sup -14/ for /spl tau/ = 10/sup 5/ s. This result confirms the theoretical predictions regarding this kind of frequency standard and makes it very attractive for satellite navigation and space applications in which a simple and reliable implementation is required, and the short and medium term stability (till one day) is the main concern.