Holographic measurement of gain and linewidth enhancement factor in semiconductor waveguides

We present a new methodology for measuring the gain and the linewidth enhancement factor of a semiconductor ridge-waveguide laser structure. The holographic methodology is based on a modified Mach-Zehnder interferometer. Compared with existing methods, the holographic setup allows to measure intensity and phase related properties such as optical gain and linewidth enhancement factor spectrally and spatially resolved. The obtained values agree well with data acquired from standard gain measurements.