The Turn on Transient and Formation of Localised Structures of a Long Cavity Laser

Amy Roche

Long cavity lasers have a wide range of potential applications including optical diagnostics and communication. For application in Optical Coherence Tomography (OCT), the coherence properties of these lasers are of major importance as they affect the image quality. The coherence of long cavity semiconductor OCT lasers is limited by the presence of intensity dropouts, associated with solutions of the Complex Ginzburg-Landau Equation known as Nozaki-Bekki Holes. We study the formation of such localised structures from the turn on of the laser. Theoretically, the laser is described by delayed differential equations, describing the evolution of the electric field and carrier density of the laser. The cores of the localised structures exhibit chaotic dynamics leading to the emission of amplitude waves, which can interact with other structures, leading to chaotic motion in the anomalous dispersion regime.