Inversion dependent non-linear coupling in laterally coupled semiconductor lasers

Abstract

The study of coupled semiconductor lasers is gaining in popularity, both due to the drive towards integrated optical components, but also due to the large variety of dynamics that coupled lasers can exhibit [1]. Since the integration of optoelectronic devices requires the placement of multiple components on a single chip, these components are generally, intentionally or unintentionally, coupled to some degree and therefore the underlying physics of coupled semiconductor lasers is of great interest also for integration technology. Here, we will present the simulation of two laterally coupled Fabry-Perot type semiconductor lasers, separated by about 4 µm, the so-called twin-stripe lasers. For an in-depth analysis of these devices we refer to [2]. We will investigate the effects on the dynamics of an inversion dependant coupling between the lasers. It has earlier been shown that two main mechanisms for coupling exist for coupling of the field in twin-stripe lasers: coherent coupling of the optical fields and incoherent coupling, where the gain of one laser contributes with stimulated emission photons to the field of the neighboring lasers [3]. Our emphasis will be on the coherent type of coupling. In a rate-equations type of description the coupling strength between the two laser stripes is quantified by the coupling rate. So far, it was assumed that this coupling is constant and independent of the carrier fluctuations in each stripe. However, recent theoretical work, using coupled wave-guide theory has shown that the inversion dynamics will cause the coupling rate to fluctuate and alter the coupling strength. In the next section we present a short overview of the underlying theory and the simulation conditions, followed by presentation of the results. We will end with some concluding remarks