Supersymmetric Single Lateral Mode GaN-based Edge-emitting Lasers

Ł. Piskorski, T. Czyszanowski (Lodz University of Technology, Poland)

One of the methods used to increase the power of a semiconductor laser is to increase the size of the area through which radiation is emitted. This leads to multi-mode laser operation, which is not acceptable for many applications. High power can also be achieved by creating a laser array. However, in the case of a typical laser array, which consists of many identical single-mode lasers, a multi-mode emission is typically observed. This problem can be solved by using the recently presented concept of supersymmetric laser arrays [1,2]. By coupling two one-dimensional matrices with a complex structure, it offers the possibility of suppressing all undesirable higher-order mods. In our research, we focused on developing the concept of supersymmetric laser arrays. It involves replacing the laser array responsible for emitting radiation with a single laser whose etched ridge has a width comparable to the width of the array it replaces. This approach relaxes technological effort and enables electrically driven supersymmetric lasers. The advantages of our proposed solution were demonstrated by performing a computer simulation for a structure based on a nitride edge-emitting laser. A similar approach can be found in [3], where theoretical analysis was applied for a GaAs-based structure with an InGaAs/GaAs active region. However, in [3] the effects associated with the inhomogeneous temperature distribution inside the structure are ignored. We took them into account in our model by introducing a volumetric heat source of a given heat generation rate into the active region of the modelled structure. In our calculations, we considered laser structures with different geometrical parameters. We present an in-depth numerical analysis of the effect of these parameters on the suppression of higher-order modes and show that by applying the concept of supersymmetric laser arrays developed by us, it is possible to increase the power of emitted radiation while maintaining a single-mode emission spectrum.