Self-consistent far-field blooming analysis for high-power Fabry-Perot laser diodes

Joachim Piprek, Bernd Witzigmann, Marek Osinski, Fritz Henneberger, Yasuhiko Arakawa
2013 Physics and Simulation of Optoelectronic Devices XXI  
High-power broad-area laser diodes often suffer from a widening of the lateral far-field with rising current injection. This effect is also referred to as thermal blooming, since self-heating is considered the main cause. The non-uniform temperature profile inside the waveguide leads to a lateral refractive index profile that enhances the index guiding of laser modes (thermal lens). This paper presents a self-consistent electro-thermal-optical simulation and analysis of the thermal blooming
more » ... hermal blooming effect, including the non-uniform heat power distribution inside the laser as well as the non-uniform carrier and gain distributions inside the quantum wells. The calculated results are in good agreement with measurements. The simulations demonstrate that thermal blooming is not only caused by the rising order of lateral modes but also by the far field widening of each individual mode with increasing current. Keywords: high-power broad-area laser diode, thermal blooming, slow axis far field, self-heating, thermal lens, lateral laser modes MODELS AND PARAMETERS We employ a customized version of the LASTIP laser simulation software 4 which allows for the self-consistent combination of multi-mode wave guiding, drift-diffusion of electrons and holes, and heat flow in the transverse plane. The material parameters are the same as in Ref. 2. The heat power distribution is calculated using the local densities of carriers and current, including Joule heat, non-radiative recombination heat, heat caused by modal absorption, as well as the Peltier/Thomson effect. Besides the laser chip, the simulation domain also includes the p-side metal and heat spreading layers to accurately calculate the temperature profile T(x,y). The local refractive index N(x,y,T) is obtained from the temperature distribution using published material parameters. 5 Transversal laser modes are calculated selfconsistently from the Helmholtz equation, including anti-index guiding by carrier-induced index changes in the quantum *; phone 1-302-565-4945;
doi:10.1117/12.2004665 fatcat:xf6u2tr5qvblrjyr5wkdyaovby