Highly phase stable mode-locked lasers

The authors report on stabilizing the carrier-envelope phase of mode-locked Ti:sapphire lasers. Optimization of the construction of the lasers for ease of phase stabilization is discussed. Results demonstrating long-term phase coherence of the generated pulse train are presented, yielding a phase coherence time of at least 326 s, measurement time limited. The conversion of amplitude noise to phase noise in the microstructured fiber, which is used to obtain an octave spanning spectrum, is measured. The resulting phase noise is found to be sufficiently small so as to not corrupt the phase stabilization. Shift of carrier-envelope phase external to the laser cavity due to propagation through a dispersive material is measured.