Gain spectra of coupled InGaAsP/InP quantum wells measured with a segmented contact traveling wave device

We use an adaptation of the variable stripe length method to measure the spectral gain of InGaAsP/InP laser structures with 12 coupled quantum films as active volume. The samples are prepared with a two-segment contact stripe for current injection, so the length of the electrically pumped region can be varied between two values. From the corresponding ratio of emission intensities, the gain spectra are extracted. Their analysis with respect to the dependency on the injected carrier density shows the possibility of a simple description of the gain of coupled quantum wells. (C) 2002 American Institute of Physics.