BROAD-AREA MICROLASERS AND METHODS FOR DRIVING THEM

摘要

A multi-mode microlaser and a method for driving a multi-mode broad­area microlaser such as a multi-mode VCSEL is described such that the multi­mode microlaser shows an unexpected Gaussian-like far-field intensity distribution. The driving conditions are in general determined such that a strong reduction of the degree of spatial coherence occurs. For square pulsed driving current, these conditions are determined by the pulse duration p<SUB>d</SUB> and the pulse height p<SUB>h</SUB>. A Gaussian-like far-field intensity distribution is obtained for pulsed multi-mode broad area microlasers. The typical spatial coherence area corresponding with these driving conditions is substantially independent of the Fresnel number of the rnicrolaser. Additionally, this partial spatial coherence can be tuned by changing the driving conditions, such as e.g. the pulse shape and length.