Near-field spectroscopic analysis of the mode structure in high-power diode lasers based on a double barrier separate confinement heterostructure

摘要

An analysis of the mode structure of high-power double-barrier separate confinement DB SCH diode lasers is presented. The devices are characterized by very low vertical beam divergence (13 - 22°, depending on the design version). Modelling of the fundamental mode distribution for three different design versions of DB SCH diode lasers is discussed and the results are compared to a macroscopic characterization of the devices (far-field directional characteristics and photocurrent spectra). Microscopic measurements of the near field distribution of these diode lasers with subwavelength spatial resolution are performed by employing a Near-field Photocurrent (NPC) technique. The mode structure of diode lasers is directly visualized giving indications about the interplay between the heterostructure design and the emission characteristics.