- S. Hachey, C. Jones, and J.N. Kutz, “Stability, dynamics, and the onset of multi-pulsing in a mode-locked laser cavity using phase-sensitive amplification,” (submitted) Phys. Rev. A.
- J.N. Kutz, “Passive mode-locking using phase-sensitive amplification,” Phys. Rev. A 78, 013845 (2008).
Phase Sensitive Amplifiers
A phase-sensitive amplifier (PSA) is a device in which we take advantage of the intensity-dependent phase rotation in the laser cavity to achieve mode-locking through the use of a PSA device that amplifies (attenuates) the pulse components that are in phase (out of phase) with the pump field of the amplifier. Thus, the phase of the pump field effectively serves as the intensity-descriminator. We are interested in exploring the dynamics that arise in such systems, both in 1- and 2-dimensions.
Averaged Equations of Motions
Averaging the electromagnetic evolution equation yields a cubic-quintic Swift-Hohenberg model equation that governs the dynamics. Swift-Hohenberg equations are famously rich in their ability to generate patterns along with exhibit spatio-temporal chaos. In this case, the non-local gain couples to the linear bifurcation parameter, resulting in self-tuning feedback which has never before been studied in this system.
Mode-Locking and Pattern Formation in 2-D
Examples of pulses, all starting from a small Gaussian initial condition. The top 3 panels show the effect of increasing gain for a specific set of parameters. These top pulses also form from cavity noise. The lower three panels illustrate the rich variety of behaviors exhibited by the system. The lower left panel shows a stable arrangement of three equal pulses with a persisting pedestal. The bottom middle panel shows a stable arrangement of eight identical pulses with no pedestal, and the bottom right panel is a meta-stable pattern that varies on a slow time scale (persisting for hundreds of cavity round trips).