The differential efficiency of quantum well lasers

Using experimental measurements of spontaneous emission spectra, we have identified the components which determine the external differential injection efficiency of laser diodes. We have shown that, even though the emission from the n=l transition pins at threshold, there are contributions to /spl eta//sub o//sup d/ above threshold from both the stripe efficiency /spl eta//sub s//sup d/ and the injection efficiency /spl eta//sub i//sup d/, the latter being due to the absence of pinning outside the well.