Comparison of high power red-emitting diode laser designs for medical applications

Abstract

A comparison is made between, on the one hand, the red-emitting laser structure currently widely used for medical applications and based on an ultranarrow waveguide layer with a compressively strained QW active layer in it and, on the other hand, the red emitting laser using a broadened asymmetric waveguide structure with a bulk active layer near the p-cladding, proposed by us. It is shown that the proposed design promises substantial improvements over the ultranarrow one including lower series and thermal resistances, and higher catastrophic degradation threshold, while maintaining relatively narrow far field and allowing the typical power required for medical applications to be achieved at lower currents, particularly at elevated temperatures.