We experimentally study two Ti:sapphire optical frequency comb femtosecond regimes, respectively, with a linear and a nonlinear dependence of the carrier-envelope offset frequency (fCEO) on pump intensity. For both regimes, we study the effect of single- and multimode pump lasers on the fCEO phase noise. We demonstrate that the femtosecond regime is playing a more important role on the fCEO phase noise and stability than the pump laser type.
Here we report on absolute frequency measurements of a commercial high power CW diode-pumped solid-state laser
(Coherent Verdi-V5). This kind of lasers usually presents large frequency jitter (up to 50 MHz) both in the short term
(1 ms time scale) and in the long term (>10 s time scale). A precise measurement of absolute frequency deviations in
both temporal scales should require a set of different devices (optical cavities, optical wave-meters), each suited for
measurements only at a specific integration time. Here we demonstrate how a frequency comb can be used to overcome
this difficulty, allowing in a single step a full characterization of both short (<1 ms) and long term (> 10<sup>3</sup> s) absolute
frequency jitter with a resolution better than 1 MHz. We demonstrate in this way the flexibility of optical frequency
combs for absolute frequency measurements not only of ultra-stable lasers but also of relatively unstable lasers. The
absolute frequency calibration of the Verdi laser that we have obtained have been used in order to improve the accuracy
of the measurements of the local gravitational acceleration value with <sup>88</sup>Sr atoms trapped in 1D vertical lattices.