Low-Noise Modelocked Lasers: Pulse Dynamics, Feedback Control, and Novel Actuators

Modelocked lasers combined with phase-locking techniques have revolutionized optical clocks and precision measurements. The basic but powerful technique that has driven these advances is feedback control, which rids a laser’s output of phase or timing fluctuations. Ideally the ultimate noise level is determined by the coherence of external references. In practice, the effectiveness of this active stabilization relies on the available loop gain and bandwidth, both of which not only depend on the properties of the actuator but also on the complex dynamics of pulse evolution, gain-photon coupling, and cross-talk between actuators. In this Thesis, both the pulse dynamics and the actuator aspects of achieving low-noise level are discussed. In particular, a new type of high-bandwidth cavity loss modulator based on graphene is described. A record low-noise fiber frequency comb laser enabled by this new actuator technology is demonstrated with the graphene modulator. The pulse dynamics is analyzed in low-noise settings, which is low intracavity dispersion and nonlinearity. Specifically, an intrinsic power oscillation, arising from the interaction between a solitary pulse and continuum, is studied theoretically and experimentally, and its impact on the noise transfer properties of the laser is studied