Tailored InP-based quantum dash structures for ultra-wide gain bandwidth applications

Several InP based samples with a single InAs QDash layer embedded in In/sub 0.528/Al/sub 0.238/Ga/sub 0.234/As were grown with various dash sizes to investigate the dependence of the emission intensity and wavelength on the dash layer thickness. Photoluminescence measurements at 8 K show a good control over the emission wavelength between 1.15 /spl mu/m and 1.9 /spl mu/m. In addition, uncapped QDash layers were grown to study the QDash formation by secondary electron microscopy. These results were used to combine four QDash layers with slightly different thicknesses to distribute the gain homogeneously over a larger spectral range. With this technique a flat gain profile of over 300 nm was confirmed by photoluminescence spectroscopy.