A Cesium optical atomic clock with high optical frequency stability

We describe the greatly improved performance of a 1.5 μm optical frequency stabilized Cs atomic clock composed of a mode-hopfree mode-locked fiber laser and an acetylene optical frequency standard. The output pulse width was shortened from 7.1 to 3.4 ps by employing a phase modulator instead of an intensity modulator as a mode-locker. The optical frequency stability for an averaging time of 100 s was also improved from 1.8 × 10 ^-11 to 6.3 × 10 ^-12 by precisely controlling the laser cavity temperature.