Broad-area laser diodes with different linewidth enhancement factors (α-factors ) of 2 and 4 have been fabricated on 1.55 μm multi-quantum well structures. Far-field measurements show that the filamentation of the laser diodes is closely related to the α-factor. The full width at half maximum (FWHM) of the far-fields and the filamentation were reduced in the laser diodes with smaller α-factors. As the injection current increased, the FWHM of the far-fields also increased regardless of the value of the α-factor. This phenomenon is explained by the reduction of the filament spacing as the injection current increased. A qualitative explanation of filamentation mechanisms is given by introducing the notion of sub-aperture.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry