Active phase stabilization, synchronization and phase locking of mode-locked Ti:sapphire lasers

This manuscript covers three main ideas: carrier - envelope phase stabilization, synchronization, and phase locking of Ti:sapphire lasers. In Chapter 1, I give a review of exactly what carrier - envelope phase stabilization means in both the time and frequency domains. I discuss various schemes to stabilize the carrier - envelope phase evolution in mode locked Ti:sapphire lasers along with some interesting examples of the technology.; In Chapter 2, I present preliminary experiments with the objective of synchronizing independent mode locked femtosecond lasers. The rms timing jitter between the two lasers is 4.3 fs, observed with a 1 ms averaging time over tens of seconds. With ∼3 microsecond averaging time, the rms timing jitter is 26 fs over tens of seconds. Novel multi-stage phase locked loops allow preservation of precision timing resolution over the maximum dynamic range of delay. Synchronization between two lasers of different repetition rates is also demonstrated.; Chapter 3 describes the work done on the generation of a synthetic optical pulse by coherently combining two independent mode locked lasers. This is done by first synchronizing the lasers, and then phase locking the comb offset frequency of the two combs. By red-shifting one laser, and blue-shifting the other, we are able to generate a larger coherent bandwidth by this technique. Coherence is demonstrated with a number of techniques is both time and frequency domains. Measurements reveal a synthesized pulse with a larger coherent bandwidth than either individual laser.; Chapter 4 represents a large step forward in our active synchronization technology. With improved electronics, better laser construction, and higher bandwidth servos, we find that the timing jitter between our independent mode locked femtosecond lasers to be 580 attoseconds with a 1 ms averaging time over several seconds. With 80 ns averaging time, we find the timing jitter to be only 1.75 fs over several seconds. We also demonstrate excellent repeatability and rapid arbitrary delay setting between the two lasers. The noise floor of the phase detector is the limiting factor achieving the lowest timing jitter.