This paper presents a method for controlling the carrier-envelope phase of femtosecond mode-locked lasers using frequency-domain stabilization techniques. The authors demonstrate that by stabilizing the carrier-envelope phase, they can achieve precise control over the absolute optical frequencies of the laser. This control is used to perform direct optical frequency synthesis and measurement, which are referenced to a stable microwave clock. The method involves using a self-referencing technique to lock the frequency comb of the laser to a known optical frequency, enabling absolute optical frequency measurements. The technique is validated using temporal cross-correlation, which confirms the control of the carrier-envelope phase. The results show that the relative carrier-envelope phase can be locked to a rational fraction of the pulse repetition rate, allowing for precise optical frequency measurements. The method is demonstrated using a mode-locked laser and a self-referencing technique that does not require external optical input. The results have significant implications for extreme nonlinear optics and optical frequency metrology, as they enable high-precision measurements of optical frequencies with a single laser. The technique is also shown to be applicable for measuring the optical frequency of a rubidium two-photon transition with high accuracy. The study highlights the importance of carrier-envelope phase control in achieving precise optical frequency measurements and demonstrates the potential of this method for future optical frequency metrology applications.This paper presents a method for controlling the carrier-envelope phase of femtosecond mode-locked lasers using frequency-domain stabilization techniques. The authors demonstrate that by stabilizing the carrier-envelope phase, they can achieve precise control over the absolute optical frequencies of the laser. This control is used to perform direct optical frequency synthesis and measurement, which are referenced to a stable microwave clock. The method involves using a self-referencing technique to lock the frequency comb of the laser to a known optical frequency, enabling absolute optical frequency measurements. The technique is validated using temporal cross-correlation, which confirms the control of the carrier-envelope phase. The results show that the relative carrier-envelope phase can be locked to a rational fraction of the pulse repetition rate, allowing for precise optical frequency measurements. The method is demonstrated using a mode-locked laser and a self-referencing technique that does not require external optical input. The results have significant implications for extreme nonlinear optics and optical frequency metrology, as they enable high-precision measurements of optical frequencies with a single laser. The technique is also shown to be applicable for measuring the optical frequency of a rubidium two-photon transition with high accuracy. The study highlights the importance of carrier-envelope phase control in achieving precise optical frequency measurements and demonstrates the potential of this method for future optical frequency metrology applications.