The stabilization of the carrier-envelope phase of ultrashort laser pulses went through a rapid development from the first publication of a feasible concept in 1999 to being a mature tool for frequency metrology and attosecond science now. Using this technique, stabilization of the timing between the carrier wave and the envelope of a laser pulse with residual jitters of only 100 attoseconds has become possible. Naturally, the questions arises whether and how this can be further improved. The current work is devoted to determining the physical mechanisms which generate jitter in carrier-envelope phase stabilization. Furthermore, it is investigated whether there is a fundamental limitation to the achievable accuracy. To this end, two methods for removal of technical noise contributions are initially discussed. Different interferometer topologies are investigated and spurious interferometer noise is reduced by more than 40% using a commonpath layout. A novel two-detector based carrier-envelope phase retrieval technique for amplified laser pulses is demonstrated enabling the circumvention of the shot-noise constraint of the conventional extraction method to the maximum extent possible. Next, a novel feed-forward stabilization concept is developed that enables carrier-envelope phase stabilizations with only 20 attosecond residual timing jitter between carrier and envelope of the laser pulse. This feed-forward method is unconditionally stable against drop-out and permits the generation of a train of pulses with identical electric field structure with no additional measures. As the feed-forward concept widely avoids the technical noise sources of the conventional feedback stabilization, the resulting noise spectra exhibit only two unavoidable residual noise mechanisms: a highfrequency white noise floor stemming from shot noise in the carrier-envelope phase detection and a drift-like contribution with 1/f noise characteristics. Finally, the drift-like residual noise mechan

This thesis presents first successful experiments to carrier-envelope-phase stabilize a high-power mode-locked thin-disk oscillator and to compress the pulses emitted from this laser to durations of only a few-optical cycles. Moreover, the monograph introduces several methods to achieve power-scalability of compression and stabilization techniques. All experimental approaches are compared in detail and may serve as a guideline for developing high-power waveform controlled, few-cycle light sources which offer tremendous potential to exploit extreme nonlinear optical effects at unprecedentedly high repetition rates and to establish table-top infrared light sources with a unique combination of brilliance and bandwidth. As an example, the realization of a multi-Watt, multi-octave spanning, mid-infrared femtosecond source is described. The thesis starts with a basic introduction to the field of ultrafast laser oscillators. It subsequently presents additional details of previously published research results and establishes a connection between them. It therefore addresses both newcomers to, and experts in the field of high-power ultrafast laser development.