We describe an ultrastable cesium (Cs) atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser obtained by use of an optically pumped Cs beam tube. By adopting a 1-m-long Cs beam tube with a linewidth of 110 Hz, we have successfully obtained frequency stabilities of 4.8×10^-12 for tau=1 s and 6.3×10^-13 for tau=50 s for a 9.1926-GHz microwave output signal. This Cs atomic clock can generate an optical pulse train with the same stability as that of the obtained microwave, which allows us to deliver a frequency standard optical signal throughout the world by means of optical fiber networks.
© 2005 Optical Society of America
Masatsugu Yakabe, Ko Nito, Masato Yoshida, Masataka Nakazawa, Yasuki Koga, Ken Hagimoto, and Takeshi Ikegami, "Ultrastable cesium atomic clock with a 9.1926-GHz regeneratively mode-locked fiber laser," Opt. Lett. 30, 1512-1514 (2005)