Dispersion-induced dynamics of coupled modes in a semiconductor laser with saturable absorption

Abstract

We present an experimental and theoretical study of modal nonlinear dynamics in a specially designed dual-mode semiconductor Fabry-Perot laser with a saturable absorber. At zero bias applied to the absorber section, we have found that with increasing device current, single mode self-pulsations evolve into a complex dynamical state where the total intensity experiences regular bursts of pulsations on a constant background. Spectrally resolved measurements reveal that in this state the individual modes of the device can follow highly symmetric but oppositely directed spiralling orbits. Using a generalization of the rate equation description of a semiconductor laser with saturable absorption to the multimode case, we show that these orbits appear as a consequence of the interplay between the material dispersion in the gain and absorber sections of the laser. Our results provide insights into the factors that determine the stability of multimode states in these systems, and they can inform the development of semiconductor mode-locked lasers with tailored spectra.

Design Optimization of Passively Mode-Locked Semiconductor Lasers With Intracavity Grating Spectral Filters

“…In this case, the mode-locked state can be described as a mutually injection locked steady-state with zero net group velocity dispersion. Although these models are attractive and convenient given the natural modal picture that follows from our design approach [18], current frequency domain models are valid for small gain and loss. In addition, because these models describe the ML state as a steady-state rather than a steady peri-arXiv:1405.7614v1 [physics.optics] 29 May 2014 odic state, these models are small signal models of the mode-locked laser [21].…”

“…In order to optimize the mode-locking range of these devices for applications, efficient dynamical models are crucial for understanding the structure of the modelocking region in the phase-space of drive parameters. In general, frequency domain models extend the rate equation description of a two-section semiconductor laser [17,18] to include phase-sensitive modal interactions [19,20]. In this case, the mode-locked state can be described as a mutually injection locked steady-state with zero net group velocity dispersion.…”